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Sample records for affect species interactions

  1. Population variation affects interactions between two California salt marsh plant species more than precipitation.

    PubMed

    Noto, Akana E; Shurin, Jonathan B

    2016-02-01

    Species that occur along broad environmental gradients often vary in phenotypic traits that make them better adapted to local conditions. Variation in species interactions across gradients could therefore be due to either phenotypic differences among populations or environmental conditions that shift the balance between competition and facilitation. To understand how the environment (precipitation) and variation among populations affect species interactions, we conducted a common garden experiment using two common salt marsh plant species, Salicornia pacifica and Jaumea carnosa, from six salt marshes along the California coast encompassing a large precipitation gradient. Plants were grown alone or with an individual of the opposite species from the same site and exposed to one of three precipitation regimes. J. carnosa was negatively affected in the presence of S. pacifica, while S. pacifica was facilitated by J. carnosa. The strength of these interactions varied by site of origin but not by precipitation treatment. These results suggest that phenotypic variation among populations can affect interaction strength more than environment, despite a threefold difference in precipitation. Geographic intraspecific variation may therefore play an important role in determining the strength of interactions in communities.

  2. Predator diversity and density affect levels of predation upon strongly interactive species in temperate rocky reefs.

    PubMed

    Guidetti, Paolo

    2007-12-01

    Indirect effects of predators in the classic trophic cascade theory involve the effects of basal species (e.g. primary producers) mediated by predation upon strongly interactive consumers (e.g. grazers). The diversity and density of predators, and the way in which they interact, determine whether and how the effects of different predators on prey combine. Intraguild predation, for instance, was observed to dampen the effects of predators on prey in many ecosystems. In marine systems, species at high trophic levels are particularly susceptible to extinction (at least functionally). The loss of such species, which is mainly attributed to human activities (mostly fishing), is presently decreasing the diversity of marine predators in many areas of the world. Experimental studies that manipulate predator diversity and investigate the effects of this on strongly interactive consumers (i.e. those potentially capable of causing community-wide effects) in marine systems are scant, especially in the rocky sublittoral. I established an experiment that utilised cage enclosures to test whether the diversity and density of fish predators (two sea breams and two wrasses) would affect predation upon juvenile and adult sea urchins, the most important grazers in Mediterranean sublittoral rocky reefs. Changes in species identity (with sea breams producing major effects) and density of predators affected predation upon sea urchins more than changes in species richness per se. Predation upon adult sea urchins decreased in the presence of multiple predators, probably due to interference competition between sea breams and wrasses. This study suggests that factors that influence both fish predator diversity and density in Mediterranean rocky reefs (e.g. fishing and climate change) may have the potential to affect the predators' ability to control sea urchin population density, with possible repercussions for the whole benthic community structure.

  3. Multifunctionality is affected by interactions between green roof plant species, substrate depth, and substrate type.

    PubMed

    Dusza, Yann; Barot, Sébastien; Kraepiel, Yvan; Lata, Jean-Christophe; Abbadie, Luc; Raynaud, Xavier

    2017-04-01

    Green roofs provide ecosystem services through evapotranspiration and nutrient cycling that depend, among others, on plant species, substrate type, and substrate depth. However, no study has assessed thoroughly how interactions between these factors alter ecosystem functions and multifunctionality of green roofs. We simulated some green roof conditions in a pot experiment. We planted 20 plant species from 10 genera and five families (Asteraceae, Caryophyllaceae, Crassulaceae, Fabaceae, and Poaceae) on two substrate types (natural vs. artificial) and two substrate depths (10 cm vs. 30 cm). As indicators of major ecosystem functions, we measured aboveground and belowground biomasses, foliar nitrogen and carbon content, foliar transpiration, substrate water retention, and dissolved organic carbon and nitrates in leachates. Interactions between substrate type and depth strongly affected ecosystem functions. Biomass production was increased in the artificial substrate and deeper substrates, as was water retention in most cases. In contrast, dissolved organic carbon leaching was higher in the artificial substrates. Except for the Fabaceae species, nitrate leaching was reduced in deep, natural soils. The highest transpiration rates were associated with natural soils. All functions were modulated by plant families or species. Plant effects differed according to the observed function and the type and depth of the substrate. Fabaceae species grown on natural soils had the most noticeable patterns, allowing high biomass production and high water retention but also high nitrate leaching from deep pots. No single combination of factors enhanced simultaneously all studied ecosystem functions, highlighting that soil-plant interactions induce trade-offs between ecosystem functions. Substrate type and depth interactions are major drivers for green roof multifunctionality.

  4. The smell of change: warming affects species interactions mediated by chemical information.

    PubMed

    Sentis, Arnaud; Ramon-Portugal, Felipe; Brodeur, Jacques; Hemptinne, Jean-Louis

    2015-10-01

    Knowledge of how temperature influences an organism's physiology and behaviour is of paramount importance for understanding and predicting the impacts of climate change on species' interactions. While the behaviour of many organisms is driven by chemical information on which they rely on to detect resources, conspecifics, natural enemies and competitors, the effects of temperature on infochemical-mediated interactions remain largely unexplored. Here, we experimentally show that temperature strongly influences the emission of infochemicals by ladybeetle larvae, which, in turn, modifies the oviposition behaviour of conspecific females. Temperature also directly affects female perception of infochemicals and their oviposition behaviour. Our results suggest that temperature-mediated effects on chemical communication can influence flows across system boundaries (e.g. immigration and emigration) and thus alter the dynamics and stability of ecological networks. We therefore argue that investigating the effects of temperature on chemical communication is a crucial step towards a better understanding of the functioning of ecological communities facing rapid environmental changes.

  5. Seed trait-mediated selection by rodents affects mutualistic interactions and seedling recruitment of co-occurring tree species.

    PubMed

    Zhang, Hongmao; Yan, Chuan; Chang, Gang; Zhang, Zhibin

    2016-02-01

    As mutualists, seed dispersers may significantly affect mutualistic interactions and seedling recruitment of sympatric plants that share similar seed dispersers, but studies are rare. Here, we compared seed dispersal fitness in two co-occurring plant species (Armeniaca sibirica and Amygdalus davidiana) that inhabit warm temperate deciduous forest in northern China. We tested the hypothesis that seed trait-mediated selection by rodents may influence mutualistic interactions with rodents and then seedling establishment of co-occurring plant species. A. davidiana seeds are larger and harder (thick endocarps) than A. sibirica seeds, but they have similar levels of nutrients (crude fat, crude protein), caloric value and tannin. More A. sibirica seedlings are found in the field. Semi-natural enclosure tests indicated that the two seed species were both harvested by the same six rodent species, but that A. sibirica had mutualistic interactions (scatter hoarding) with four rodent species (Apodemus peninsulae, A. agrarius, Sciurotamias davidianus, Tamias sibiricus), and A. davidiana with only one (S. davidianus). Tagged seed dispersal experiments in the field indicated that more A. sibirica seeds were scatter-hoarded by rodents, and more A. sibirica seeds survived to the next spring and became seedlings. A. sibirica seeds derive more benefit from seed dispersal by rodents than A. davidiana seeds, particularly in years with limited seed dispersers, which well explained the higher seedling recruitment of A. sibirica compared with that of A. davidiana under natural conditions. Our results suggest that seed dispersers may play a significant role in seedling recruitment and indirect competition between co-occurring plant species.

  6. Species co-occurrence affects the trophic interactions of two juvenile reef shark species in tropical lagoon nurseries in Moorea (French Polynesia).

    PubMed

    Matich, Philip; Kiszka, Jeremy J; Mourier, Johann; Planes, Serge; Heithaus, Michael R

    2017-03-28

    Food web structure is shaped by interactions within and across trophic levels. As such, understanding how the presence and absence of predators, prey, and competitors affect species foraging patterns is important for predicting the consequences of changes in species abundances, distributions, and behaviors. Here, we used plasma δ(13)C and δ(15)N values from juvenile blacktip reef sharks (Carcharhinus melanopterus) and juvenile sicklefin lemon sharks (Negaprion acutidens) to investigate how species co-occurrence affects their trophic interactions in littoral waters of Moorea, French Polynesia. Co-occurrence led to isotopic niche partitioning among sharks within nurseries, with significant increases in δ(15)N values among sicklefin lemon sharks, and significant decreases in δ(15)N among blacktip reef sharks. Niche segregation likely promotes coexistence of these two predators during early years of growth and development, but data do not suggest coexistence affects life history traits, such as body size, body condition, and ontogenetic niche shifts. Plasticity in trophic niches among juvenile blacktip reef sharks and sicklefin lemon sharks also suggests these predators are able to account for changes in community structure, resource availability, and intra-guild competition, and may fill similar functional roles in the absence of the other species, which is important as environmental change and human impacts persist in coral reef ecosystems.

  7. Emotions and BIS/BAS components affect brain activity (ERPs and fNIRS) in observing intra-species and inter-species interactions.

    PubMed

    Balconi, Michela; Vanutelli, Maria Elide

    2016-09-01

    Affective response to observation of intra-species and inter-species interactions was considered in the present research. The brain activity (optical imaging: functional Near-Infrared Spectroscopy, fNIRS; and event-related potentials, ERPs, N200) was monitored when subjects observed interactive situations (human-human, HH; human-animal, HA) with a positive (cooperative), negative (uncooperative) or neutral (no emotional) content. In addition, cortical lateralization (more left or right prefrontal activity) and personality component (Behavioral Activation System, BAS; Behavioral Inhibition System, BIS) effects were explored. Both ERP and fNIRS showed significant brain activity increasing in response to positive and negative compared with neutral interactions for HH and HA. However, some differences were found between HH (more "negative valence" effect) and HA (more "positive valence" effect). Finally BAS and BIS were related respectively to more left (positive conditions) or right (negative conditions) hemispheric activity. These results supported the significance of affective behavior differentiating the species-specific and species-aspecific relationships.

  8. Interactions between Bifidobacterium and Bacteroides Species in Cofermentations Are Affected by Carbon Sources, Including Exopolysaccharides Produced by Bifidobacteria

    PubMed Central

    Rios-Covian, David; Arboleya, Silvia; Hernandez-Barranco, Ana M.; Alvarez-Buylla, Jorge R.; Ruas-Madiedo, Patricia; Gueimonde, Miguel

    2013-01-01

    Cocultures of strains from two Bifidobacterium and two Bacteroides species were performed with exopolysaccharides (EPS) previously purified from bifidobacteria, with inulin, or with glucose as the carbon source. Bifidobacterium longum NB667 and Bifidobacterium breve IPLA20004 grew in glucose but showed poor or no growth in complex carbohydrates (inulin, EPS E44, and EPS R1), whereas Bacteroides grew well in the four carbon sources tested. In the presence of glucose, the growth of Bacteroides thetaiotaomicron DSM-2079 was inhibited by B. breve, whereas it remained unaffected in the presence of B. longum. Ba. fragilis DSM-2151 contributed to a greater survival of B. longum, promoting changes in the synthesis of short-chain fatty acids (SCFA) and organic acids in coculture with respect to monocultures. In complex carbohydrates, cocultures of bifidobacterium strains with Ba. thetaiotaomicron did not modify the behavior of Bacteroides nor improve the poor growth of bifidobacteria. The metabolic activity of Ba. fragilis in coculture with bifidobacteria was not affected by EPS, but greater survival of bifidobacteria at late stages of incubation occurred in cocultures than in monocultures, leading to a higher production of acetic acid than in monocultures. Therefore, cocultures of Bifidobacterium and Bacteroides can behave differently against fermentable carbohydrates as a function of the specific characteristics of the strains from each species. These results stress the importance of considering specific species and strain interactions and not simply higher taxonomic divisions in the relationship among intestinal microbial populations and their different responses to probiotics and prebiotics. PMID:24077708

  9. Elevated atmospheric carbon dioxide concentration affects interactions between Spodoptera exigua (Lepidoptera: Noctuidae) larvae and two host plant species outdoors

    SciTech Connect

    Caulfield, F.; Bunce, J.A. )

    1994-08-01

    Beet armyworm, Spodoptera exigua (Huebner), larvae were placed on sugarbeet (Beta vulgaris L.) and pigweed (Amaranthus hybridus L.) plants in outdoor chambers in which the plants were growing at either the ambient ([approximately] 350 [mu]l liter[sup [minus]1]) or ambient plus 350 [mu]l liter[sup [minus]1] ([approximately] 700 [mu]l liter[sup [minus]1]) carbon dioxide concentration. A series of experiments was performed to determine if larvae reduced plant growth differently at the two carbon dioxide concentrations in either species and if the insect growth or survival differed with carbon dioxide concentration. Leaf nitrogen, water, starch, and soluble carbohydrate contents were measured to assess carbon dioxide concentration effects on leaf quality. Insect feeding significantly reduced plant growth in sugarbeet plants at 350 [mu]l liter[sup [minus]1] but not at 700 [mu]l liter[sup [minus]1] nor in pigweed at either carbon dioxide concentration. Larval survival was greater on sugarbeet plants at the elevated carbon dioxide concentration. Increased survival occurred only if the insects were at the elevated carbon dioxide concentration and consumed leaf material grown at the elevated concentration. Leaf quality was only marginally affected by growth at elevated carbon dioxide concentration in these experiments. The results indicate that in designing experiments to predict effects of elevated atmospheric carbon dioxide concentrations on plant-insect interactions, both plants and insects should be exposed to the experimental carbon dioxide concentrations, as well as to as realistic environmental conditions as possible.

  10. Seasonal Changes Affect Root Prunasin Concentration in Prunus serotina and Override Species Interactions between P. serotina and Quercus petraea.

    PubMed

    Robakowski, Piotr; Bielinis, Ernest; Stachowiak, Jerzy; Mejza, Iwona; Bułaj, Bartosz

    2016-03-01

    The allocation of resources to chemical defense can decrease plant growth and photosynthesis. Prunasin is a cyanogenic glycoside known for its role in defense against herbivores and other plants. In the present study, fluctuations of prunasin concentrations in roots of Prunus serotina seedlings were hypothesized to be: (1) dependent on light, air temperature, and humidity; (2) affected by competition between Prunus serotina and Quercus petraea seedlings, with mulching with Prunus serotina leaves; (3) connected with optimal allocation of resources. For the first time, we determined prunasin concentration in roots on several occasions during the vegetative season. The results indicate that seasonal changes have more pronounced effects on prunasin concentration than light regime and interspecific competition. Prunus serotina invested more nitrogen in the synthesis of prunasin under highly restricted light conditions than in higher light environments. In full sun, prunasin in roots of Prunus serotina growing in a monoculture was correlated with growth and photosynthesis, whereas these relationships were not found when interspecific competition with mulching was a factor. The study demonstrates that prunasin concentration in Prunus serotina roots is the result of species-specific adaptation, light and temperature conditions, ontogenetic shift, and, to a lesser extent, interspecific plant-plant interactions.

  11. How interacting fungal species and mineral nitrogen inputs affect transfer of nitrogen from litter via arbuscular mycorrhizal mycelium.

    PubMed

    He, Yuejun; Cornelissen, J Hans C; Zhong, Zhangcheng; Dong, Ming; Jiang, Changhong

    2017-04-01

    In the karst landscape, widespread in the world including southern China, soil nutrient supply is strongly constrained. In such environments, arbuscular mycorrhizal (AM) fungi may facilitate plant nutrient uptake. However, the possible role of different AM fungal species, and their interactions, especially in transferring nitrogen (N) from litter to plant, is poorly understood. We conducted two microcosm experiments to investigate the role that two karst soil AM fungi, Glomus etunicatum and Glomus mosseae, play in the transfer of N from decomposing litter to the host plant and to determine how N availability influences these processes. In experiment 1, Cinnamomum camphora tree seedlings were grown in compartments inoculated with G. etunicatum. Lolium perenne leaf litter labeled with δ(15)N was added to the soil in unplanted compartments. Compartments containing the δ(15)N labeled litter were either accessible to hyphae but not to seedling roots or were not accessible to hyphae or roots. The addition of mineral N to one of the host compartments at the start of the experiment significantly increased the biomass of the C. camphora seedlings, N content and N:P ratio, AM mycelium length, and soil microbial biomass carbon and N. However, significantly, more δ(15)N was acquired, from the leaf litter by the AM hyphae and transferred to the host when mineral N was not added to the soil. In experiment 2, in which C. camphora seedlings were inoculated with both G. etunicatum and G. mosseae rather than with G. mosseae alone, there was a significant increase in mycelial growth (50.21%), in soil microbial biomass carbon (417.73%) in the rhizosphere, and in the amount of δ(15)N that was transferred to the host. These findings suggest that maintaining AM fungal diversity in karst soils could be important for mediating N transfer from organic material to host plants in N-poor soils.

  12. Anthropogenic noise affects vocal interactions.

    PubMed

    McMullen, Heather; Schmidt, Rouven; Kunc, Hansjoerg P

    2014-03-01

    Animal communication plays a crucial role in many species, and it involves a sender producing a signal and a receiver responding to that signal. The shape of a signal is determined by selection pressures acting upon it. One factor that exerts selection on acoustic signals is the acoustic environment through which the signal is transmitted. Recent experimental studies clearly show that senders adjust their signals in response to increased levels of anthropogenic noise. However, to understand how noise affects the whole process of communication, it is vital to know how noise affects the receiver's response during vocal interactions. Therefore, we experimentally manipulated ambient noise levels to expose male European robins (Erithacus rubecula) to two playback treatments consisting of the same song: one with noise and another one without noise. We found that males responding to a conspecific in a noise polluted environment increased minimum frequency and decreased song complexity and song duration. Thus, we show that the whole process of communication is affected by noise, not just the behaviour of the sender.

  13. How variation between individuals affects species coexistence.

    PubMed

    Hart, Simon P; Schreiber, Sebastian J; Levine, Jonathan M

    2016-08-01

    Although the effects of variation between individuals within species are traditionally ignored in studies of species coexistence, the magnitude of intraspecific variation in nature is forcing ecologists to reconsider. Compelling intuitive arguments suggest that individual variation may provide a previously unrecognised route to diversity maintenance by blurring species-level competitive differences or substituting for species-level niche differences. These arguments, which are motivating a large body of empirical work, have rarely been evaluated with quantitative theory. Here we incorporate intraspecific variation into a common model of competition and identify three pathways by which this variation affects coexistence: (1) changes in competitive dynamics because of nonlinear averaging, (2) changes in species' mean interaction strengths because of variation in underlying traits (also via nonlinear averaging) and (3) effects on stochastic demography. As a consequence of the first two mechanisms, we find that intraspecific variation in competitive ability increases the dominance of superior competitors, and intraspecific niche variation reduces species-level niche differentiation, both of which make coexistence more difficult. In addition, individual variation can exacerbate the effects of demographic stochasticity, and this further destabilises coexistence. Our work provides a theoretical foundation for emerging empirical interests in the effects of intraspecific variation on species diversity.

  14. Host plant species affects virulence in monarch butterfly parasites.

    PubMed

    de Roode, Jacobus C; Pedersen, Amy B; Hunter, Mark D; Altizer, Sonia

    2008-01-01

    1. Studies have considered how intrinsic host and parasite properties determine parasite virulence, but have largely ignored the role of extrinsic ecological factors in its expression. 2. We studied how parasite genotype and host plant species interact to determine virulence of the protozoan parasite Ophryocystis elektroscirrha (McLaughlin & Myers 1970) in the monarch butterfly Danaus plexippus L. We infected monarch larvae with one of four parasite genotypes and reared them on two milkweed species that differed in their levels of cardenolides: toxic chemicals involved in predator defence. 3. Parasite infection, replication and virulence were affected strongly by host plant species. While uninfected monarchs lived equally long on both plant species, infected monarchs suffered a greater reduction in their life spans (55% vs. 30%) on the low-cardenolide vs. the high-cardenolide host plant. These life span differences resulted from different levels of parasite replication in monarchs reared on the two plant species. 4. The virulence rank order of parasite genotypes was unaffected by host plant species, suggesting that host plant species affected parasite genotypes similarly, rather than through complex plant species-parasite genotype interactions. 5. Our results demonstrate that host ecology importantly affects parasite virulence, with implications for host-parasite dynamics in natural populations.

  15. Mood Swings: An Affective Interactive Art System

    NASA Astrophysics Data System (ADS)

    Bialoskorski, Leticia S. S.; Westerink, Joyce H. D. M.; van den Broek, Egon L.

    The progress in the field of affective computing enables the realization of affective consumer products, affective games, and affective art. This paper describes the affective interactive art system Mood Swings, which interprets and visualizes affect expressed by a person. Mood Swings is founded on the integration of a framework for affective movements and a color model. This enables Mood Swings to recognize affective movement characteristics as expressed by a person and display a color that matches the expressed emotion. With that, a unique interactive system is introduced, which can be considered as art, a game, or a combination of both.

  16. Species coexistence in a lattice-structured habitat: effects of species dispersal and interactions.

    PubMed

    Ying, Zhixia; Liao, Jinbao; Wang, Shichang; Lu, Hui; Liu, Yongjie; Ma, Liang; Li, Zhenqing

    2014-10-21

    Opinions differ on how the spatial distribution of species over space affects species coexistence. Here, we constructed both mean-field and pair approximation (PA) models to explore the effects of interspecific and intraspecific interactions and dispersal modes on species coexistence. We found that spatial structure resulting from species dispersal traits and neighboring interactions in PA model did not promote coexistence if two species had the same traits, though it might intensify the contact frequency of intraspecific competition. If two species adopt different dispersal modes, the spatial structure in PA would make the coexistence or founder control less likely since it alters the species effective birth rate. This suggests that the spatial distribution caused by neighboring interactions and local dispersal does not affect species coexistence unless it adequately alters the effective birth rate for two species. Besides, we modeled how the initial densities and patterns affected population dynamics and revealed how the final spatial pattern was generated.

  17. Affect Control in International Interactions

    ERIC Educational Resources Information Center

    Heise, David R.; Lerner, Steven J.

    2006-01-01

    This research tests the proposition that national leaders generate international interactions in the process of maintaining sentiments about nations and international actions. The analysis deals with 1,934 international incidents in which one of 25 Middle Eastern nations responded twice within four weeks to an instigation by another of the 25…

  18. Estimating Effects of Species Interactions on Populations of Endangered Species.

    PubMed

    Roth, Tobias; Bühler, Christoph; Amrhein, Valentin

    2016-04-01

    Global change causes community composition to change considerably through time, with ever-new combinations of interacting species. To study the consequences of newly established species interactions, one available source of data could be observational surveys from biodiversity monitoring. However, approaches using observational data would need to account for niche differences between species and for imperfect detection of individuals. To estimate population sizes of interacting species, we extended N-mixture models that were developed to estimate true population sizes in single species. Simulations revealed that our model is able to disentangle direct effects of dominant on subordinate species from indirect effects of dominant species on detection probability of subordinate species. For illustration, we applied our model to data from a Swiss amphibian monitoring program and showed that sizes of expanding water frog populations were negatively related to population sizes of endangered yellow-bellied toads and common midwife toads and partly of natterjack toads. Unlike other studies that analyzed presence and absence of species, our model suggests that the spread of water frogs in Central Europe is one of the reasons for the decline of endangered toad species. Thus, studying population impacts of dominant species on population sizes of endangered species using data from biodiversity monitoring programs should help to inform conservation policy and to decide whether competing species should be subject to population management.

  19. The Affective Regulation of Social Interaction*

    PubMed Central

    Clore, Gerald L.; Pappas, Jesse

    2008-01-01

    The recent publication of David Heise’s Expressive Order (2007) provides an occasion for discussing some of the key ideas in Affect Control Theory. The theory proposes that a few dimensions of affective meaning provide a common basis for interrelating personal identities and social actions. It holds that during interpersonal interactions, social behavior is continually regulated to maintain an affective tone compatible with whatever social roles or identities define the situation. We outline the intellectual history of the proposed dimensions and of the idea that each social action invites an action from the other that has a particular location along these dimensions. We also relate these ideas to the Affect-as-Information hypothesis, an approach that often guides research in psychology on the role of affect in regulating judgment and thought. PMID:18461152

  20. Affective loop experiences: designing for interactional embodiment

    PubMed Central

    Höök, Kristina

    2009-01-01

    Involving our corporeal bodies in interaction can create strong affective experiences. Systems that both can be influenced by and influence users corporeally exhibit a use quality we name an affective loop experience. In an affective loop experience, (i) emotions are seen as processes, constructed in the interaction, starting from everyday bodily, cognitive or social experiences; (ii) the system responds in ways that pull the user into the interaction, touching upon end users' physical experiences; and (iii) throughout the interaction the user is an active, meaning-making individual choosing how to express themselves—the interpretation responsibility does not lie with the system. We have built several systems that attempt to create affective loop experiences with more or less successful results. For example, eMoto lets users send text messages between mobile phones, but in addition to text, the messages also have colourful and animated shapes in the background chosen through emotion-gestures with a sensor-enabled stylus pen. Affective Diary is a digital diary with which users can scribble their notes, but it also allows for bodily memorabilia to be recorded from body sensors mapping to users' movement and arousal and placed along a timeline. Users can see patterns in their bodily reactions and relate them to various events going on in their lives. The experiences of building and deploying these systems gave us insights into design requirements for addressing affective loop experiences, such as how to design for turn-taking between user and system, how to create for ‘open’ surfaces in the design that can carry users' own meaning-making processes, how to combine modalities to create for a ‘unity’ of expression, and the importance of mirroring user experience in familiar ways that touch upon their everyday social and corporeal experiences. But a more important lesson gained from deploying the systems is how emotion processes are co-constructed and

  1. Affective loop experiences: designing for interactional embodiment.

    PubMed

    Höök, Kristina

    2009-12-12

    Involving our corporeal bodies in interaction can create strong affective experiences. Systems that both can be influenced by and influence users corporeally exhibit a use quality we name an affective loop experience. In an affective loop experience, (i) emotions are seen as processes, constructed in the interaction, starting from everyday bodily, cognitive or social experiences; (ii) the system responds in ways that pull the user into the interaction, touching upon end users' physical experiences; and (iii) throughout the interaction the user is an active, meaning-making individual choosing how to express themselves-the interpretation responsibility does not lie with the system. We have built several systems that attempt to create affective loop experiences with more or less successful results. For example, eMoto lets users send text messages between mobile phones, but in addition to text, the messages also have colourful and animated shapes in the background chosen through emotion-gestures with a sensor-enabled stylus pen. Affective Diary is a digital diary with which users can scribble their notes, but it also allows for bodily memorabilia to be recorded from body sensors mapping to users' movement and arousal and placed along a timeline. Users can see patterns in their bodily reactions and relate them to various events going on in their lives. The experiences of building and deploying these systems gave us insights into design requirements for addressing affective loop experiences, such as how to design for turn-taking between user and system, how to create for 'open' surfaces in the design that can carry users' own meaning-making processes, how to combine modalities to create for a 'unity' of expression, and the importance of mirroring user experience in familiar ways that touch upon their everyday social and corporeal experiences. But a more important lesson gained from deploying the systems is how emotion processes are co-constructed and experienced

  2. The dissimilarity of species interaction networks.

    PubMed

    Poisot, Timothée; Canard, Elsa; Mouillot, David; Mouquet, Nicolas; Gravel, Dominique

    2012-12-01

    In a context of global changes, and amidst the perpetual modification of community structure undergone by most natural ecosystems, it is more important than ever to understand how species interactions vary through space and time. The integration of biogeography and network theory will yield important results and further our understanding of species interactions. It has, however, been hampered so far by the difficulty to quantify variation among interaction networks. Here, we propose a general framework to study the dissimilarity of species interaction networks over time, space or environments, allowing both the use of quantitative and qualitative data. We decompose network dissimilarity into interactions and species turnover components, so that it is immediately comparable to common measures of β-diversity. We emphasise that scaling up β-diversity of community composition to the β-diversity of interactions requires only a small methodological step, which we foresee will help empiricists adopt this method. We illustrate the framework with a large dataset of hosts and parasites interactions and highlight other possible usages. We discuss a research agenda towards a biogeographical theory of species interactions.

  3. How to Predict Molecular Interactions between Species?

    PubMed Central

    Schulze, Sylvie; Schleicher, Jana; Guthke, Reinhard; Linde, Jörg

    2016-01-01

    Organisms constantly interact with other species through physical contact which leads to changes on the molecular level, for example the transcriptome. These changes can be monitored for all genes, with the help of high-throughput experiments such as RNA-seq or microarrays. The adaptation of the gene expression to environmental changes within cells is mediated through complex gene regulatory networks. Often, our knowledge of these networks is incomplete. Network inference predicts gene regulatory interactions based on transcriptome data. An emerging application of high-throughput transcriptome studies are dual transcriptomics experiments. Here, the transcriptome of two or more interacting species is measured simultaneously. Based on a dual RNA-seq data set of murine dendritic cells infected with the fungal pathogen Candida albicans, the software tool NetGenerator was applied to predict an inter-species gene regulatory network. To promote further investigations of molecular inter-species interactions, we recently discussed dual RNA-seq experiments for host-pathogen interactions and extended the applied tool NetGenerator (Schulze et al., 2015). The updated version of NetGenerator makes use of measurement variances in the algorithmic procedure and accepts gene expression time series data with missing values. Additionally, we tested multiple modeling scenarios regarding the stimuli functions of the gene regulatory network. Here, we summarize the work by Schulze et al. (2015) and put it into a broader context. We review various studies making use of the dual transcriptomics approach to investigate the molecular basis of interacting species. Besides the application to host-pathogen interactions, dual transcriptomics data are also utilized to study mutualistic and commensalistic interactions. Furthermore, we give a short introduction into additional approaches for the prediction of gene regulatory networks and discuss their application to dual transcriptomics data. We

  4. How context dependent are species interactions?

    PubMed

    Chamberlain, Scott A; Bronstein, Judith L; Rudgers, Jennifer A

    2014-07-01

    The net effects of interspecific species interactions on individuals and populations vary in both sign (-, 0, +) and magnitude (strong to weak). Interaction outcomes are context-dependent when the sign and/or magnitude change as a function of the biotic or abiotic context. While context dependency appears to be common, its distribution in nature is poorly described. Here, we used meta-analysis to quantify variation in species interaction outcomes (competition, mutualism, or predation) for 247 published articles. Contrary to our expectations, variation in the magnitude of effect sizes did not differ among species interactions, and while mutualism was most likely to change sign across contexts (and predation least likely), mutualism did not strongly differ from competition. Both the magnitude and sign of species interactions varied the most along spatial and abiotic gradients, and least as a function of the presence/absence of a third species. However, the degree of context dependency across these context types was not consistent among mutualism, competition and predation studies. Surprisingly, study location and ecosystem type varied in the degree of context dependency, with laboratory studies showing the highest variation in outcomes. We urge that studying context dependency per se, rather than focusing only on mean outcomes, can provide a general method for describing patterns of variation in nature.

  5. Factors affecting antimicrobial susceptibility of Fusobacterium species.

    PubMed Central

    Rowland, M D; Del Bene, V E; Lewis, J W

    1987-01-01

    Fifteen clinical isolates of Fusobacterium species were studied to determine their quality of growth on five agar media, their susceptibility to penicillin, cephalothin, cefoxitin, and cefotaxime, the inoculum effect, and the presence of L forms and beta-lactamase. Wilkins-Chalgren agar supported confluent growth best, but Fusobacterium nucleatum exhibited poor growth on all agar media. Most isolates exhibited poor reproducibility of MIC results with repeated agar dilution testing. However, most isolates were susceptible to all antibiotics at the breakpoint concentrations. No inoculum effect was observed, but preparation of an inoculum at a 0.5 McFarland nephelometric standard produced a lower than expected number of CFU (10(6) CFU) in some isolates. L forms were frequently seen. No beta-lactamase was found. The variability in MICs seen with beta-lactam antibiotics was not found when clindamycin was tested. MIC studies with Fusobacterium spp. may be complicated by poor growth on agar media, poor reproducibility, and small inoculum size. PMID:3494743

  6. The influence of interspecific interactions on species range expansion rates

    USGS Publications Warehouse

    Svenning, Jens-Christian; Gravel, Dominique; Holt, Robert D.; Schurr, Frank M.; Thuiller, Wilfried; Münkemüller, Tamara; Schiffers, Katja H.; Dullinger, Stefan; Edwards, Thomas C.; Hickler, Thomas; Higgins, Steven I.; Nabel, Julia E.M.S.; Pagel, Jörn; Normand, Signe

    2014-01-01

    Ongoing and predicted global change makes understanding and predicting species’ range shifts an urgent scientific priority. Here, we provide a synthetic perspective on the so far poorly understood effects of interspecific interactions on range expansion rates. We present theoretical foundations for how interspecific interactions may modulate range expansion rates, consider examples from empirical studies of biological invasions and natural range expansions as well as process-based simulations, and discuss how interspecific interactions can be more broadly represented in process-based, spatiotemporally explicit range forecasts. Theory tells us that interspecific interactions affect expansion rates via alteration of local population growth rates and spatial displacement rates, but also via effects on other demographic parameters. The best empirical evidence for interspecific effects on expansion rates comes from studies of biological invasions. Notably, invasion studies indicate that competitive dominance and release from specialized enemies can enhance expansion rates. Studies of natural range expansions especially point to the potential for competition from resident species to reduce expansion rates. Overall, it is clear that interspecific interactions may have important consequences for range dynamics, but also that their effects have received too little attention to robustly generalize on their importance. We then discuss how interspecific interactions effects can be more widely incorporated in dynamic modeling of range expansions. Importantly, models must describe spatiotemporal variation in both local population dynamics and dispersal. Finally, we derive the following guidelines for when it is particularly important to explicitly represent interspecific interactions in dynamic range expansion forecasts: if most interacting species show correlated spatial or temporal trends in their effects on the target species, if the number of interacting species is low

  7. The influence of interspecific interactions on species range expansion rates

    PubMed Central

    Svenning, Jens-Christian; Gravel, Dominique; Holt, Robert D.; Schurr, Frank M.; Thuiller, Wilfried; Münkemüller, Tamara; Schiffers, Katja H.; Dullinger, Stefan; Edwards, Thomas C.; Hickler, Thomas; Higgins, Steven I.; Nabel, Julia E. M. S.; Pagel, Jörn; Normand, Signe

    2014-01-01

    Ongoing and predicted global change makes understanding and predicting species’ range shifts an urgent scientific priority. Here, we provide a synthetic perspective on the so far poorly understood effects of interspecific interactions on range expansion rates. We present theoretical foundations for how interspecific interactions may modulate range expansion rates, consider examples from empirical studies of biological invasions and natural range expansions as well as process-based simulations, and discuss how interspecific interactions can be more broadly represented in process-based, spatiotemporally explicit range forecasts. Theory tells us that interspecific interactions affect expansion rates via alteration of local population growth rates and spatial displacement rates, but also via effects on other demographic parameters. The best empirical evidence for interspecific effects on expansion rates comes from studies of biological invasions. Notably, invasion studies indicate that competitive dominance and release from specialized enemies can enhance expansion rates. Studies of natural range expansions especially point to the potential for competition from resident species to reduce expansion rates. Overall, it is clear that interspecific interactions may have important consequences for range dynamics, but also that their effects have received too little attention to robustly generalize on their importance. We then discuss how interspecific interactions effects can be more widely incorporated in dynamic modeling of range expansions. Importantly, models must describe spatiotemporal variation in both local population dynamics and dispersal. Finally, we derive the following guidelines for when it is particularly important to explicitly represent interspecific interactions in dynamic range expansion forecasts: if most interacting species show correlated spatial or temporal trends in their effects on the target species, if the number of interacting species is low

  8. What Can Interaction Webs Tell Us About Species Roles?

    PubMed Central

    Sander, Elizabeth L.; Wootton, J. Timothy; Allesina, Stefano

    2015-01-01

    The group model is a useful tool to understand broad-scale patterns of interaction in a network, but it has previously been limited in use to food webs, which contain only predator-prey interactions. Natural populations interact with each other in a variety of ways and, although most published ecological networks only include information about a single interaction type (e.g., feeding, pollination), ecologists are beginning to consider networks which combine multiple interaction types. Here we extend the group model to signed directed networks such as ecological interaction webs. As a specific application of this method, we examine the effects of including or excluding specific interaction types on our understanding of species roles in ecological networks. We consider all three currently available interaction webs, two of which are extended plant-mutualist networks with herbivores and parasitoids added, and one of which is an extended intertidal food web with interactions of all possible sign structures (+/+, -/0, etc.). Species in the extended food web grouped similarly with all interactions, only trophic links, and only nontrophic links. However, removing mutualism or herbivory had a much larger effect in the extended plant-pollinator webs. Species removal even affected groups that were not directly connected to those that were removed, as we found by excluding a small number of parasitoids. These results suggest that including additional species in the network provides far more information than additional interactions for this aspect of network structure. Our methods provide a useful framework for simplifying networks to their essential structure, allowing us to identify generalities in network structure and better understand the roles species play in their communities. PMID:26197151

  9. Species interactions differ in their genetic robustness

    DOE PAGES

    Chubiz, Lon M.; Granger, Brian R.; Segre, Daniel; ...

    2015-04-14

    Conflict and cooperation between bacterial species drive the composition and function of microbial communities. Stability of these emergent properties will be influenced by the degree to which species' interactions are robust to genetic perturbations. We use genome-scale metabolic modeling to computationally analyze the impact of genetic changes when Escherichia coli and Salmonella enterica compete, or cooperate. We systematically knocked out in silico each reaction in the metabolic network of E. coli to construct all 2583 mutant stoichiometric models. Then, using a recently developed multi-scale computational framework, we simulated the growth of each mutant E. coli in the presence of S.more » enterica. The type of interaction between species was set by modulating the initial metabolites present in the environment. We found that the community was most robust to genetic perturbations when the organisms were cooperating. Species ratios were more stable in the cooperative community, and community biomass had equal variance in the two contexts. Additionally, the number of mutations that have a substantial effect is lower when the species cooperate than when they are competing. In contrast, when mutations were added to the S. enterica network the system was more robust when the bacteria were competing. These results highlight the utility of connecting metabolic mechanisms and studies of ecological stability. Cooperation and conflict alter the connection between genetic changes and properties that emerge at higher levels of biological organization.« less

  10. Pharmaceutical formulation affects titanocene transferrin interactions.

    PubMed

    Buettner, Katherine M; Snoeberger, Robert C; Batista, Victor S; Valentine, Ann M

    2011-10-07

    Since the discovery of the anticancer activity of titanocene dichloride (TDC), many derivatives have been developed and evaluated. MKT4, a soluble, water-stable formulation of TDC, was used for both Phase I and Phase II human clinical trials. This formulation is investigated here by using (1)H and (13)C NMR, FT-ICR mass spectrometry, and UV/vis-detected pH-dependent speciation. DFT calculations are also utilized to assess the likelihood of proposed species. Human serum transferrin has been identified as a potential vehicle for the Ti anticancer drugs; these studies examine whether and how formulation of TDC as MKT4 may influence its interactions, both thermodynamic and kinetic, with human serum transferrin by using UV/vis absorption and fluorescence quenching. MKT4 binds differently than TDC to transferrin, showing different kinetics of binding as well as a different molar absorptivity of binding (7500 M(-1) cm(-1) per site). Malate, used in the buffer for MKT4 administration, acts as a synergistic anion for Ti binding, shifting the tyrosine to Ti charge transfer energy and decreasing the molar absorptivity to 5000 M(-1) cm(-1) per site. These differences may have had consequences after the change from TDC to MKT4 in human clinical trials.

  11. Changes in interacting species with disturbance

    NASA Astrophysics Data System (ADS)

    Cole, Glen F.

    1987-03-01

    Human-influenced changes in the diversity and abundance of native wildlife in a southern boreal forest area, which became a national park in 1975, are used to develop working hypotheses for predicting and subsequently measuring the effects of disturbance or restoration programs on groups of interacting species. Changes from presettlement conditions began with early 1900 hunting, which eliminated woodland caribou ( Rangifer tarandus) and elk ( Cervus elaphus), and reduced moose ( Alces alces) to the low numbers which still persist. Increases in white-tailed deer ( Odocoileus virginianus), as these other cervid species became less abundant or absent, provided enough alternative food to sustain the system's carnivores until plant succession on previously burned or logged areas also caused deer to decline. With increased competition for reduced food, carnivore species also became less abundant or absent and overexploited some prey populations. The abilities of interacting species to maintain dynamically stable populations or persist varied with their different capacities to compensate for increased exploitation or competition. These relationships suggested a possible solution to the problem of predicting the stability of populations in disturbed systems. For the 1976 1985 period, a hypothesis that the increased protection of wildlife from exploitation in a national park would restore a more diverse, abundant, and productive fauna had to be rejected.

  12. Species interactions differ in their genetic robustness

    SciTech Connect

    Chubiz, Lon M.; Granger, Brian R.; Segre, Daniel; Harcombe, William R.

    2015-04-14

    Conflict and cooperation between bacterial species drive the composition and function of microbial communities. Stability of these emergent properties will be influenced by the degree to which species' interactions are robust to genetic perturbations. We use genome-scale metabolic modeling to computationally analyze the impact of genetic changes when Escherichia coli and Salmonella enterica compete, or cooperate. We systematically knocked out in silico each reaction in the metabolic network of E. coli to construct all 2583 mutant stoichiometric models. Then, using a recently developed multi-scale computational framework, we simulated the growth of each mutant E. coli in the presence of S. enterica. The type of interaction between species was set by modulating the initial metabolites present in the environment. We found that the community was most robust to genetic perturbations when the organisms were cooperating. Species ratios were more stable in the cooperative community, and community biomass had equal variance in the two contexts. Additionally, the number of mutations that have a substantial effect is lower when the species cooperate than when they are competing. In contrast, when mutations were added to the S. enterica network the system was more robust when the bacteria were competing. These results highlight the utility of connecting metabolic mechanisms and studies of ecological stability. Cooperation and conflict alter the connection between genetic changes and properties that emerge at higher levels of biological organization.

  13. Climate change and species interactions: ways forward.

    PubMed

    Angert, Amy L; LaDeau, Shannon L; Ostfeld, Richard S

    2013-09-01

    With ongoing and rapid climate change, ecologists are being challenged to predict how individual species will change in abundance and distribution, how biotic communities will change in structure and function, and the consequences of these climate-induced changes for ecosystem functioning. It is now well documented that indirect effects of climate change on species abundances and distributions, via climatic effects on interspecific interactions, can outweigh and even reverse the direct effects of climate. However, a clear framework for incorporating species interactions into projections of biological change remains elusive. To move forward, we suggest three priorities for the research community: (1) utilize tractable study systems as case studies to illustrate possible outcomes, test processes highlighted by theory, and feed back into modeling efforts; (2) develop a robust analytical framework that allows for better cross-scale linkages; and (3) determine over what time scales and for which systems prediction of biological responses to climate change is a useful and feasible goal. We end with a list of research questions that can guide future research to help understand, and hopefully mitigate, the negative effects of climate change on biota and the ecosystem services they provide.

  14. Fish introductions reveal the temperature dependence of species interactions.

    PubMed

    Hein, Catherine L; Öhlund, Gunnar; Englund, Göran

    2014-01-22

    A major area of current research is to understand how climate change will impact species interactions and ultimately biodiversity. A variety of environmental conditions are rapidly changing owing to climate warming, and these conditions often affect both the strength and outcome of species interactions. We used fish distributions and replicated fish introductions to investigate environmental conditions influencing the coexistence of two fishes in Swedish lakes: brown trout (Salmo trutta) and pike (Esox lucius). A logistic regression model of brown trout and pike coexistence showed that these species coexist in large lakes (more than 4.5 km(2)), but not in small, warm lakes (annual air temperature more than 0.9-1.5°C). We then explored how climate change will alter coexistence by substituting climate scenarios for 2091-2100 into our model. The model predicts that brown trout will be extirpated from approximately half of the lakes where they presently coexist with pike and from nearly all 9100 lakes where pike are predicted to invade. Context dependency was critical for understanding pike-brown trout interactions, and, given the widespread occurrence of context-dependent species interactions, this aspect will probably be critical for accurately predicting climate impacts on biodiversity.

  15. Hydraulic lift and tolerance to salinity of semiarid species: consequences for species interactions.

    PubMed

    Armas, Cristina; Padilla, Francisco M; Pugnaire, Francisco I; Jackson, Robert B

    2010-01-01

    The different abilities of plant species to use ephemeral or permanent water sources strongly affect physiological performance and species coexistence in water-limited ecosystems. In addition to withstanding drought, plants in coastal habitats often have to withstand highly saline soils, an additional ecological stress. Here we tested whether observed competitive abilities and C-water relations of two interacting shrub species from an arid coastal system were more related to differences in root architecture or salinity tolerance. We explored water sources of interacting Juniperus phoenicea Guss. and Pistacia lentiscus L. plants by conducting physiology measurements, including water relations, CO2 exchange, photochemical efficiency, sap osmolality, and water and C isotopes. We also conducted parallel soil analyses that included electrical conductivity, humidity, and water isotopes. During drought, Pistacia shrubs relied primarily on permanent salty groundwater, while isolated Juniperus plants took up the scarce and relatively fresh water stored in upper soil layers. As drought progressed further, the physiological activity of Juniperus plants nearly stopped while Pistacia plants were only slightly affected. Juniperus plants growing with Pistacia had stem-water isotopes that matched Pistacia, unlike values for isolated Juniperus plants. This result suggests that Pistacia shrubs supplied water to nearby Juniperus plants through hydraulic lift. This lifted water, however, did not appear to benefit Juniperus plants, as their physiological performance with co-occurring Pistacia plants was poor, including lower water potentials and rates of photosynthesis than isolated plants. Juniperus was more salt sensitive than Pistacia, which withstood salinity levels similar to that of groundwater. Overall, the different abilities of the two species to use salty water appear to drive the outcome of their interaction, resulting in asymmetric competition where Juniperus is negatively

  16. Ecological interactions in Aedes species on Reunion Island.

    PubMed

    Bagny Beilhe, L; Delatte, H; Juliano, S A; Fontenille, D; Quilici, S

    2013-12-01

    Two invasive, container-breeding mosquito species, Aedes aegypti (Stegomyia aegypti) and Aedes albopictus (Stegomyia albopicta) (Diptera: Culicidae), have different distribution patterns on Reunion Island. Aedes albopictus occurs in all areas and Ae. aegypti colonizes only some restricted areas already occupied by Ae. albopictus. This study investigates the abiotic and biotic ecological mechanisms that determine the distribution of Aedes species on Reunion Island. Life history traits (duration of immature stages, survivorship, fecundity, estimated finite rate of increase) in Ae. aegypti and Ae. albopictus were compared at different temperatures. These fitness measures were characterized in both species in response to competitive interactions among larvae. Aedes aegypti was drastically affected by temperature, performing well only at around 25 °C, at which it achieved its highest survivorship and greatest estimated rate of increase. The narrow distribution of this species in the field on Reunion Island may thus relate to its poor ability to cope with unfavourable temperatures. Aedes aegypti was also more negatively affected by high population densities and to some extent by interactions with Ae. albopictus, particularly in the context of limited food supplies. Aedes albopictus exhibited better population performance across a range of environmental conditions. Its ecological plasticity and its superior competitive ability relative to its congener may further enhance its invasion success on Reunion Island.

  17. Affect in Human-Robot Interaction

    DTIC Science & Technology

    2014-01-01

    even without deliberately modeling them: for example, if a robot backs away from a staircase it might be interpreted as a fear of falling by a person...chosen to deliberately embed explicit models of affect into robots, with the express purpose of enhancing the relationship between the human and robot...many psychological models of human affect have been explored. Two examples that have had commercial success are described

  18. Affective responses in tamarins elicited by species-specific music.

    PubMed

    Snowdon, Charles T; Teie, David

    2010-02-23

    Theories of music evolution agree that human music has an affective influence on listeners. Tests of non-humans provided little evidence of preferences for human music. However, prosodic features of speech ('motherese') influence affective behaviour of non-verbal infants as well as domestic animals, suggesting that features of music can influence the behaviour of non-human species. We incorporated acoustical characteristics of tamarin affiliation vocalizations and tamarin threat vocalizations into corresponding pieces of music. We compared music composed for tamarins with that composed for humans. Tamarins were generally indifferent to playbacks of human music, but responded with increased arousal to tamarin threat vocalization based music, and with decreased activity and increased calm behaviour to tamarin affective vocalization based music. Affective components in human music may have evolutionary origins in the structure of calls of non-human animals. In addition, animal signals may have evolved to manage the behaviour of listeners by influencing their affective state.

  19. Linear filtering reveals false negatives in species interaction data

    PubMed Central

    Stock, Michiel; Poisot, Timothée; Waegeman, Willem; De Baets, Bernard

    2017-01-01

    Species interaction datasets, often represented as sparse matrices, are usually collected through observation studies targeted at identifying species interactions. Due to the extensive required sampling effort, species interaction datasets usually contain many false negatives, often leading to bias in derived descriptors. We show that a simple linear filter can be used to detect false negatives by scoring interactions based on the structure of the interaction matrices. On 180 different datasets of various sizes, sparsities and ecological interaction types, we found that on average in about 75% of the cases, a false negative interaction got a higher score than a true negative interaction. Furthermore, we show that this filter is very robust, even when the interaction matrix contains a very large number of false negatives. Our results demonstrate that unobserved interactions can be detected in species interaction datasets, even without resorting to information about the species involved. PMID:28383526

  20. Bacterial Community Diversity Harboured by Interacting Species

    PubMed Central

    Bili, Mikaël; Cortesero, Anne Marie; Mougel, Christophe; Gauthier, Jean Pierre; Ermel, Gwennola; Simon, Jean Christophe; Outreman, Yannick; Terrat, Sébastien; Mahéo, Frédérique; Poinsot, Denis

    2016-01-01

    All animals are infected by microbial partners that can be passengers or residents and influence many biological traits of their hosts. Even if important factors that structure the composition and abundance of microbial communities within and among host individuals have been recently described, such as diet, developmental stage or phylogeny, few studies have conducted cross-taxonomic comparisons, especially on host species related by trophic relationships. Here, we describe and compare the microbial communities associated with the cabbage root fly Delia radicum and its three major parasitoids: the two staphylinid beetles Aleochara bilineata and A. bipustulata and the hymenopteran parasitoid Trybliographa rapae. For each species, two populations from Western France were sampled and microbial communities were described through culture independent methods (454 pyrosequencing). Each sample harbored at least 59 to 261 different bacterial phylotypes but was strongly dominated by one or two. Microbial communities differed markedly in terms of composition and abundance, being mainly influenced by phylogenetic proximity but also geography to a minor extent. Surprisingly, despite their strong trophic interaction, parasitoids shared a very low proportion of microbial partners with their insect host. Three vertically transmitted symbionts from the genus Wolbachia, Rickettsia, and Spiroplasma were found in this study. Among them, Wolbachia and Spiroplasma were found in both the cabbage fly and at least one of its parasitoids, which could result from horizontal transfers through trophic interactions. Phylogenetic analysis showed that this hypothesis may explain some but not all cases. More work is needed to understand the dynamics of symbiotic associations within trophic network and the effect of these bacterial communities on the fitness of their hosts. PMID:27258532

  1. Facial Affect Reciprocity in Dyadic Interactions

    DTIC Science & Technology

    2012-09-01

    predicted. Surprisingly, however, it was not the exchange of emotional expressions per se that was the best predictor of the various outcomes ; instead...suggest a role for the concept of emotion regulation in predicting better behavioral outcomes in dyadic interaction. Emotion regulation refers to the...degree to which individuals can manage and modify their emotional reactions in order to achieve constructive, goal-directed outcomes . One component

  2. Habitat interaction between two species of chipmunk in the Basin and Range Province of Nevada

    USGS Publications Warehouse

    Lowrey, Christopher; Longshore, Kathleen

    2013-01-01

    Interspecies interactions can affect how species are distributed, put constraints on habitat expansion, and reduce the fundamental niche of the affected species. Using logistic regression, we analyzed and compared 174 Tamias palmeri and 94 Tamias panamintinus within an isolated mountain range of the Basin and Range Province of southern Nevada. Tamias panamintinus was more likely to use pinyon/ponderosa/fir mixed forests than pinyon alone, compared to random sites. In the presence of T palmeri, however, interaction analyses indicated T. panamintinus was less likely to occupy the mixed forests and more likely near large rocks on southern aspects. This specie s-by-habitat interaction data suggest that T. palmeri excludes T panamintinus from areas of potentially suitable habitat. Climate change may adversely affect species of restricted distribution. Habitat isolation and species interactions in this region may thus increase survival risks as climate temperatures rise.

  3. Factors affecting Culicoides species composition and abundance in avian nests.

    PubMed

    Martínez-de la Puente, J; Merino, S; Tomás, G; Moreno, J; Morales, J; Lobato, E; Talavera, S; Sarto I Monteys, V

    2009-08-01

    Mechanisms affecting patterns of vector distribution among host individuals may influence the population and evolutionary dynamics of vectors, hosts and the parasites transmitted. We studied the role of different factors affecting the species composition and abundance of Culicoides found in nests of the blue tit (Cyanistes caeruleus). We identified 1531 females and 2 males of 7 different Culicoides species in nests, with C. simulator being the most abundant species, followed by C. kibunensis, C. festivipennis, C. segnis, C. truncorum, C. pictipennis and C. circumscriptus. We conducted a medicationxfumigation experiment randomly assigning bird's nests to different treatments, thereby generating groups of medicated and control pairs breeding in fumigated and control nests. Medicated pairs were injected with the anti-malarial drug Primaquine diluted in saline solution while control pairs were injected with saline solution. The fumigation treatment was carried out using insecticide solution or water for fumigated and control nests respectively. Brood size was the main factor associated with the abundance of biting midges probably because more nestlings may produce higher quantities of vector attractants. In addition, birds medicated against haemoparasites breeding in non-fumigated nests supported a higher abundance of C. festivipennis than the rest of the groups. Also, we found that the fumigation treatment reduced the abundance of engorged Culicoides in both medicated and control nests, thus indicating a reduction of feeding success produced by the insecticide. These results represent the first evidence for the role of different factors in affecting the Culicoides infracommunity in wild avian nests.

  4. Root-Zone Glyphosate Exposure Adversely Affects Two Ditch Species

    PubMed Central

    Saunders, Lyndsay E.; Koontz, Melissa B.; Pezeshki, Reza

    2013-01-01

    Glyphosate, one of the most applied herbicides globally, has been extensively studied for its effects on non-target organisms. In the field, following precipitation, glyphosate runs off into agricultural ditches where it infiltrates into the soil and thus may encounter the roots of vegetation. These edge-of-field ditches share many characteristics with wetlands, including the ability to reduce loads of anthropogenic chemicals through uptake, transformation, and retention. Different species within the ditches may have a differential sensitivity to exposure of the root zone to glyphosate, contributing to patterns of abundance of ruderal species. The present laboratory experiment investigated whether two species commonly found in agricultural ditches in southcentral United States were affected by root zone glyphosate in a dose-dependent manner, with the objective of identifying a sublethal concentration threshold. The root zone of individuals of Polygonum hydropiperoides and Panicum hemitomon were exposed to four concentrations of glyphosate. Leaf chlorophyll content was measured, and the ratio of aboveground biomass to belowground biomass and survival were quantified. The findings from this study showed that root zone glyphosate exposure negatively affected both species including dose-dependent reductions in chlorophyll content. P. hydropiperdoides showed the greatest negative response, with decreased belowground biomass allocation and total mortality at the highest concentrations tested. PMID:24833234

  5. Immigration rates and species niche characteristics affect the relationship between species richness and habitat heterogeneity in modeled meta-communities.

    PubMed

    Bar-Massada, Avi

    2015-01-01

    The positive relationship between habitat heterogeneity and species richness is a cornerstone of ecology. Recently, it was suggested that this relationship should be unimodal rather than linear due to a tradeoff between environmental heterogeneity and population sizes. Increased environmental heterogeneity will decrease effective habitat sizes, which in turn will increase the rate of local species extinctions. The occurrence of the unimodal richness-heterogeneity relationship at the habitat scale was confirmed in both empirical and theoretical studies. However, it is unclear whether it can occur at broader spatial scales, for meta-communities in diverse and patchy landscapes. Here, I used a spatially explicit meta-community model to quantify the roles of two species-level characteristics, niche width and immigration rates, on the type of the richness-heterogeneity relationship at the landscape scale. I found that both positive and unimodal richness-heterogeneity relationships can occur in meta-communities in patchy landscapes. The type of the relationship was affected by the interactions between inter-patch immigration rates and species' niche widths. Unimodal relationships were prominent in meta-communities comprising species with wide niches but low inter-patch immigration rates. In contrast, meta-communities consisting of species with narrow niches and high immigration rates exhibited positive relationships. Meta-communities comprising generalist species are therefore likely to exhibit unimodal richness-heterogeneity relationships as long as low immigration rates prevent rescue effects and patches are small. The richness-heterogeneity relationship at the landscape scale is dictated by species' niche widths and inter-patch immigration rates. These immigration rates, in turn, depend on the interaction between species dispersal capabilities and habitat connectivity, highlighting the roles of both species traits and landscape structure in generating the richness

  6. Reproductive interference determines persistence and exclusion in species interactions.

    PubMed

    Kishi, Shigeki; Nishida, Takayoshi; Tsubaki, Yoshitaka

    2009-09-01

    1. Reproductive interference is a negative interspecific sexual interaction that adversely affects the fitness of males and females during reproductive process. Theoretical studies suggest that because reproductive interference is characterized by positive frequency dependence it is far more likely to cause species exclusion than the density dependence of resource competition. However, the respective contributions of resource competition and reproductive interference to species exclusion, which have been frequently observed in many competition studies, remain unclear. 2. We show that reproductive interference is a far more critical cause of species exclusion than resource competition in the competition between Callosobruchus bean weevil species. In competition experiments over several generations, we manipulated the initial relative abundance of the adzuki bean beetle, Callosobruchus chinensis, and the southern cowpea beetle, Callosobruchus maculatus. When the initial adult ratio of C. chinensis : C. maculatus were 6 : 2 and 4 : 4, C. chinensis excluded C. maculatus. However, when C. maculatus was four times more abundant than C. chinensis at the start, we observed the opposite outcome. 3. A behavioural experiment using adults of the two species revealed asymmetric reproductive interference. The fecundity and longevity of C. maculatus females, but not those of C. chinensis females, decreased when the females were kept with heterospecific males. Fecundities of females of both species decreased as the number of heterospecific males increased. In contrast, resource competition at the larval stage resulted in higher survival of C. maculatus than of C. chinensis. 4. These results suggest that the positive frequency-dependent effect of reproductive interference resulted in species exclusion, depending on the initial population ratio of the two species, and the asymmetry of the interference resulted in C. chinensis being dominant in this study, as in previous studies

  7. Spatial heterogeneity of plant-soil feedback affects root interactions and interspecific competition.

    PubMed

    Hendriks, Marloes; Ravenek, Janneke M; Smit-Tiekstra, Annemiek E; van der Paauw, Jan Willem; de Caluwe, Hannie; van der Putten, Wim H; de Kroon, Hans; Mommer, Liesje

    2015-08-01

    Plant-soil feedback is receiving increasing interest as a factor influencing plant competition and species coexistence in grasslands. However, we do not know how spatial distribution of plant-soil feedback affects plant below-ground interactions. We investigated the way in which spatial heterogeneity of soil biota affects competitive interactions in grassland plant species. We performed a pairwise competition experiment combined with heterogeneous distribution of soil biota using four grassland plant species and their soil biota. Patches were applied as quadrants of 'own' and 'foreign' soils from all plant species in all pairwise combinations. To evaluate interspecific root responses, species-specific root biomass was quantified using real-time PCR. All plant species suffered negative soil feedback, but strength was species-specific, reflected by a decrease in root growth in own compared with foreign soil. Reduction in root growth in own patches by the superior plant competitor provided opportunities for inferior competitors to increase root biomass in these patches. These patterns did not cascade into above-ground effects during our experiment. We show that root distributions can be determined by spatial heterogeneity of soil biota, affecting plant below-ground competitive interactions. Thus, spatial heterogeneity of soil biota may contribute to plant species coexistence in species-rich grasslands.

  8. Species interactions of the alewife in the Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1970-01-01

    The alewife (Alosa pseudoharengus) has caused serious problems in the Great Lakes for almost 100 years. It entered Lake Ontario in abundance via the Erie Canal during the 1860's when major piscivores were declining, and became the dominant species in the lake during the 1870's. The alewife subsequently spread throughout the Great Lakes and became the dominant species in Lakes Huron and Michigan as major piscivores declined. In lakes where it became extremely abundant, the shallow-water planktivores declined in the first decade after alewife establishment, the minor piscivores increased then declined in the second decade, and the deep-water planktivores declined in the third decade. The consequence has been a general reduction in fishery productivity. Rehabilitation will require extreme reduction of the alewife, and restoration of an interacting complex of deep- and shallow-water forage species, and minor and major piscivores, either by reestablishing species affected by the alewife, or by the introduction of new species that can thrive under the new ecological conditions of the lakes.

  9. High-order species interactions shape ecosystem diversity

    PubMed Central

    Bairey, Eyal; Kelsic, Eric D.; Kishony, Roy

    2016-01-01

    Classical theory shows that large communities are destabilized by random interactions among species pairs, creating an upper bound on ecosystem diversity. However, species interactions often occur in high-order combinations, whereby the interaction between two species is modulated by one or more other species. Here, by simulating the dynamics of communities with random interactions, we find that the classical relationship between diversity and stability is inverted for high-order interactions. More specifically, while a community becomes more sensitive to pairwise interactions as its number of species increases, its sensitivity to three-way interactions remains unchanged, and its sensitivity to four-way interactions actually decreases. Therefore, while pairwise interactions lead to sensitivity to the addition of species, four-way interactions lead to sensitivity to species removal, and their combination creates both a lower and an upper bound on the number of species. These findings highlight the importance of high-order species interactions in determining the diversity of natural ecosystems. PMID:27481625

  10. Making a Bad Situation Worse: An Invasive Species Altering the Balance of Interactions between Local Species

    PubMed Central

    2016-01-01

    Biological invasions pose a significant threat to biodiversity, especially on oceanic islands. One of the primary explanations for the success of plant invaders is direct suppression of competitors. However, indirect interactions can also be important, although they are often overlooked in studies on biological invasion. The shrub Leucaena leucocephala is a widespread island invader with putative allelopathic effects on the germination and growth of other species. We quantified the impact of Leucaena on plant communities richness on an oceanic Brazilian island and, through nursery experiments, investigated the potential for allelopathic effects on the germination of Erythrina velutina, a native species that is often absent from stands of Leucaena. Additionally, in a manipulative field experiment, we examined the direct and indirect effects (mediated by the native species Capparis flexuosa) of the invader on the development of Erythrina. The species richness in invaded sites was lower than in uninvaded sites, and Capparis was the only native species that was frequently present in invaded sites. In the nursery experiments, we found no evidence that Leucaena affects the germination of Erythrina. In the field experiments, the odds of Erythrina germination were lower in the presence of Leucaena litter, but higher in the presence of Leucaena trees. However, the survival and growth of Erythrina were considerably inhibited by the presence of Leucaena trees. The isolated effect of native Capparis on the germination and growth of Erythrina varied from positive to neutral. However, when Capparis and Leucaena were both present, their combined negative effects on Erythrina were worse than the effect of Leucaena alone, which may be attributed to indirect effects. This study provides the first empirical evidence that the balance of the interactions between native species can shift from neutral/positive to negative in the presence of an exotic species. PMID:27010846

  11. Making a Bad Situation Worse: An Invasive Species Altering the Balance of Interactions between Local Species.

    PubMed

    Mello, Thayná Jeremias; Oliveira, Alexandre Adalardo de

    2016-01-01

    Biological invasions pose a significant threat to biodiversity, especially on oceanic islands. One of the primary explanations for the success of plant invaders is direct suppression of competitors. However, indirect interactions can also be important, although they are often overlooked in studies on biological invasion. The shrub Leucaena leucocephala is a widespread island invader with putative allelopathic effects on the germination and growth of other species. We quantified the impact of Leucaena on plant communities richness on an oceanic Brazilian island and, through nursery experiments, investigated the potential for allelopathic effects on the germination of Erythrina velutina, a native species that is often absent from stands of Leucaena. Additionally, in a manipulative field experiment, we examined the direct and indirect effects (mediated by the native species Capparis flexuosa) of the invader on the development of Erythrina. The species richness in invaded sites was lower than in uninvaded sites, and Capparis was the only native species that was frequently present in invaded sites. In the nursery experiments, we found no evidence that Leucaena affects the germination of Erythrina. In the field experiments, the odds of Erythrina germination were lower in the presence of Leucaena litter, but higher in the presence of Leucaena trees. However, the survival and growth of Erythrina were considerably inhibited by the presence of Leucaena trees. The isolated effect of native Capparis on the germination and growth of Erythrina varied from positive to neutral. However, when Capparis and Leucaena were both present, their combined negative effects on Erythrina were worse than the effect of Leucaena alone, which may be attributed to indirect effects. This study provides the first empirical evidence that the balance of the interactions between native species can shift from neutral/positive to negative in the presence of an exotic species.

  12. Multiple peaks of species abundance distributions induced by sparse interactions

    NASA Astrophysics Data System (ADS)

    Obuchi, Tomoyuki; Kabashima, Yoshiyuki; Tokita, Kei

    2016-08-01

    We investigate the replicator dynamics with "sparse" symmetric interactions which represent specialist-specialist interactions in ecological communities. By considering a large self-interaction u , we conduct a perturbative expansion which manifests that the nature of the interactions has a direct impact on the species abundance distribution. The central results are all species coexistence in a realistic range of the model parameters and that a certain discrete nature of the interactions induces multiple peaks in the species abundance distribution, providing the possibility of theoretically explaining multiple peaks observed in various field studies. To get more quantitative information, we also construct a non-perturbative theory which becomes exact on tree-like networks if all the species coexist, providing exact critical values of u below which extinct species emerge. Numerical simulations in various different situations are conducted and they clarify the robustness of the presented mechanism of all species coexistence and multiple peaks in the species abundance distributions.

  13. Mitochondrial-nuclear epistasis affects fitness within species but does not contribute to fixed incompatibilities between species of Drosophila

    PubMed Central

    Montooth, Kristi L.; Meiklejohn, Colin D.; Abt, Dawn N.; Rand, David M.

    2010-01-01

    Efficient mitochondrial function requires physical interactions between the proteins encoded by the mitochondrial and nuclear genomes. Co-evolution between these genomes may result in the accumulation of incompatibilities between divergent lineages. We test whether mitochondrial-nuclear incompatibilities have accumulated within the Drosophila melanogaster species subgroup by combining divergent mitochondrial and nuclear lineages and quantifying the effects on relative fitness. Precise placement of nine mtDNAs from D. melanogaster, D. simulans and D. mauritiana into two D. melanogaster nuclear genetic backgrounds reveals significant mitochondrial-nuclear epistasis affecting fitness in females. Combining the mitochondrial genomes with three different D. melanogaster X chromosomes reveals significant epistasis for male fitness between X-linked and mitochondrial variation. However, we find no evidence that the more than 500 fixed differences between the mitochondrial genomes of D. melanogaster and the D. simulans species complex are incompatible with the D. melanogaster nuclear genome. Rather, the interactions of largest effect occur between mitochondrial and nuclear polymorphisms that segregate within species of the D. melanogaster species subgroup. We propose that a low mitochondrial substitution rate, resulting from a low mutation rate and/or efficient purifying selection, precludes the accumulation of mitochondrial-nuclear incompatibilities among these Drosophila species. PMID:20624176

  14. Life history affects how species experience succession in pen shell metacommunities.

    PubMed

    Munguia, Pablo

    2014-04-01

    In nature, very few species are common and broadly distributed. Most species are rare and occupy few sites; this pattern is ubiquitous across habitats and taxa. In spatially structured communities (metacommunities), regional distribution and local abundance may change as the relative effects of within-habitat processes (e.g., species interactions) and among-habitat processes (e.g., dispersal) may vary through succession. A field experiment with the marine benthic inhabitants of pen shells (Atrina rigida) tested how common and rare species respond to succession and metacommunity size. I followed community development through time and partitioned species into sessile and motile based on their natural history. Rare species drive diversity patterns and are influenced by metacommunity size: there are strong abundance-distribution differences between common and rare species in large metacommunities, but motile species show lower rates of change than sessile species. In small metacommunities both common and rare species have similar changes through time; the dichotomous distinction of common and rare species is not present. Edge effects in metacommunities affect species' changes in distribution and abundance. In large metacommunities diversity is higher in edge habitats relative to small metacommunities during early succession. However, edge effects benefit motile species over time in small metacommunities showing a rapid increase in diversity. Individual mobility is sensitive to regional community size and allows individuals to sort among different communities. In contrast, sessile species do not show this edge effect. Metacommunity theory is a useful framework for understanding spatially structured communities, but the natural history of coexisting species cannot be ignored.

  15. Factors affecting the efficient transformation of Colletotrichum species

    USGS Publications Warehouse

    Redman, Regina S.; Rodriguez, Rusty J.

    1994-01-01

    Factors affecting the efficient transformation of Colletotrichum species. Experimental Mycology, 18, 230-246. Twelve isolates representing four species of Colletotrichum were transformed either by enhanced protoplast, restriction enzyme-mediated integration (REMI), or electroporation-mediated protocols. The enhanced protoplast transformation protocol resulted in 100- and 50-fold increases in the transformation efficiencies of Colletotrichum lindemuthianum and C. magna , respectively. REMI transformation involved the use of Hin dIII and vector DNA linearized with HindIII to increase the number of integration events and potential gene disruptions in the fungal genome. Combining the enhanced protoplast and the REMI protocols resulted in a 22-fold increase in the number of hygromycin/nystatin-resistant mutants in C. lindemuthianum . Electroporation-mediated transformation was performed on mycelial fragments and spores of four Colletotrichum species, resulting in efficiencies of up to 1000 transformants/μg DNA. The pHA1.3 vector which confers hygromycin resistance contains telomeric sequences from Fusarium oxysporum , transforms by autonomous replication and genomic integration, and was essential for elevated transformation efficiencies of 100 to 10,000 transformants/μg DNA. Modifications of pHA1.3 occurred during bacterial amplification and post fungal transformation resulting in plasmids capable of significantly elevated transformation efficiencies in C. lindemuthianum.

  16. Species interaction mechanisms maintain grassland plant species diversity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Theory has outpaced empirical research in pursuit of identifying mechanisms maintaining species diversity. Here we demonstrate how data from diversity-ecosystem functioning experiments can be used to test maintenance of diversity theory. We predict that grassland plant diversity can be maintained by...

  17. Affective Behavior and Nonverbal Interaction in Collaborative Virtual Environments

    ERIC Educational Resources Information Center

    Peña, Adriana; Rangel, Nora; Muñoz, Mirna; Mejia, Jezreel; Lara, Graciela

    2016-01-01

    While a person's internal state might not be easily inferred through an automatic computer system, within a group, people express themselves through their interaction with others. The group members' interaction can be then helpful to understand, to certain extent, its members' affective behavior in any case toward the task at hand. In this…

  18. Factors affecting Archaeal Lipid Compositions of the Sulfolobus Species

    NASA Astrophysics Data System (ADS)

    He, L.; Han, J.; Wei, Y.; Lin, L.; Wei, Y.; Zhang, C.

    2010-12-01

    Temperature is the best known variable affecting the distribution of the archaeal glycerol dibiphytanyl glycerol tetraethers (GDGTs) in marine and freshwater systems. Other variables such as pH, ionic strength, or bicarbonate concentration may also affect archaeal GDGTs in terrestrial systems. Studies of pure cultures can help us pinpoint the specific effects these variables may have on archaeal lipid distribution in natural environments. In this study, three Sulfolobus species (HG4, HB5-2, HB9-6) isolated from Tengchong hot springs (pH 2-3, temperature 73-90°C) in China were used to investigate the effects of temperature, pH, substrate, and type of strain on the composition of GDGTs. Results showed that increase in temperature had negative effects on the relative contents of GDGT-0 (no cyclopentyl rings), GDGT-1 (one cyclopentyl ring), GDGT-2 and GDGT-3 but positive effects on GDGT-4, GDGT-4', GDGT-5 and GDGT-5'. Increase in pH, on the other hand, had negative effects on GDGT-0, GDGT-1, GDGT-4', GDGT-5 and GDGT-5', and positive effects on GDGT-3 and GDGT-4. GDGT-2 remained relatively constant with changing pH. When the HG4 was grown on different substrates, GDGT-5 was five time more abundant in sucrose-grown cultures than in yeast extract- or sulfur- grown cultures, suggesting that carbohydrates may stimulate the production of GDGT-5. For all three species, the ring index (average number of rings) of GDGTs correlated positively with incubation temperature. In HG4, ring index was much lower at optimal pH (3.5) than at other pH values. Ring index of HB5-2 or HB9-6 is higher than that of HG4, suggesting that speciation may affect the degree of cyclization of GDGT of the Sulfolobus. These results indicate that individual archaeal lipids respond differently to changes in environmental variables, which may be also species specific.

  19. Conservation Tillage Affects Species Composition But Not Species Diversity: A Comparative Study in Northern Italy

    NASA Astrophysics Data System (ADS)

    Boscutti, Francesco; Sigura, Maurizia; Gambon, Nadia; Lagazio, Corrado; Krüsi, Bertil O.; Bonfanti, Pierluigi

    2015-02-01

    Conservation tillage (CT) is widely considered to be a practice aimed at preserving several ecosystem functions. In the literature, however, there seems to be no clear pattern with regard to its benefits on species diversity and species composition. In Northern Italy, we compared species composition and diversity of both vascular plants and Carabids under two contrasting tillage systems, i.e., CT and conventional tillage, respectively. We hypothesized a significant positive impact of CT on both species diversity and composition. We also considered the potential influence of crop type. The tillage systems were studied under open field conditions with three types of annual crops (i.e., maize, soybean, and winter cereals), using a split-plot design on pairs of adjacent fields. Linear mixed models were applied to test tillage system, crop, and interaction effects on diversity indices. Plant and Carabids communities were analyzed by multivariate methods (CCA). On the whole, 136 plant and 51 carabid taxa were recorded. The two tillage systems studied did not differ in floristic or carabid diversity. Species composition, by contrast, proved to be characteristic for each combination of tillage system and crop type. In particular, CT fields were characterized by nutrient demanding weeds and the associated Carabids. The differences were especially pronounced in fields with winter cereals. The same was true for the flora and Carabids along the field boundaries. For studying the effects of CT practices on the sustainability of agro-ecosystems, therefore, the focus should be on species composition rather than on diversity measures.

  20. Macroecological signals of species interactions in the Danish avifauna.

    PubMed

    Gotelli, Nicholas J; Graves, Gary R; Rahbek, Carsten

    2010-03-16

    The role of intraspecific and interspecific interactions in structuring biotic communities at fine spatial scales is well documented, but the signature of species interactions at coarser spatial scales is unclear. We present evidence that species interactions may be a significant factor in mediating the regional assembly of the Danish avifauna. Because >95% of breeding species (n = 197) are migratory, we hypothesized that dispersal limitation would not be important and that breeding distributions would largely reflect resource availability and autecological habitat preferences. Instead, we detected a striking pattern of spatial segregation between ecologically similar species at two spatial scales with a suite of null models that factored in the spatial distribution of habitats in Denmark as well as population size and biomass of each species. Habitat utilization analyses indicated that community-wide patterns of spatial segregation could not be attributed to the patchy distribution of habitat or to gross differences in habitat utilization among ecologically similar species. We hypothesize that, when habitat patch size is limited, conspecific attraction in concert with interspecific territoriality may result in spatially segregated distributions of ecologically similar species at larger spatial scales. In the Danish avifauna, the effects of species interactions on community assembly appear pervasive and can be discerned at grain sizes up to four orders of magnitude larger than those of individual territories. These results suggest that species interactions should be incorporated into species distribution modeling algorithms designed to predict species occupancy patterns based on environmental variables.

  1. Macroecological signals of species interactions in the Danish avifauna

    PubMed Central

    Gotelli, Nicholas J.; Graves, Gary R.; Rahbek, Carsten

    2010-01-01

    The role of intraspecific and interspecific interactions in structuring biotic communities at fine spatial scales is well documented, but the signature of species interactions at coarser spatial scales is unclear. We present evidence that species interactions may be a significant factor in mediating the regional assembly of the Danish avifauna. Because >95% of breeding species (n = 197) are migratory, we hypothesized that dispersal limitation would not be important and that breeding distributions would largely reflect resource availability and autecological habitat preferences. Instead, we detected a striking pattern of spatial segregation between ecologically similar species at two spatial scales with a suite of null models that factored in the spatial distribution of habitats in Denmark as well as population size and biomass of each species. Habitat utilization analyses indicated that community-wide patterns of spatial segregation could not be attributed to the patchy distribution of habitat or to gross differences in habitat utilization among ecologically similar species. We hypothesize that, when habitat patch size is limited, conspecific attraction in concert with interspecific territoriality may result in spatially segregated distributions of ecologically similar species at larger spatial scales. In the Danish avifauna, the effects of species interactions on community assembly appear pervasive and can be discerned at grain sizes up to four orders of magnitude larger than those of individual territories. These results suggest that species interactions should be incorporated into species distribution modeling algorithms designed to predict species occupancy patterns based on environmental variables. PMID:20194760

  2. Species interactions alter evolutionary responses to a novel environment.

    PubMed

    Lawrence, Diane; Fiegna, Francesca; Behrends, Volker; Bundy, Jacob G; Phillimore, Albert B; Bell, Thomas; Barraclough, Timothy G

    2012-01-01

    Studies of evolutionary responses to novel environments typically consider single species or perhaps pairs of interacting species. However, all organisms co-occur with many other species, resulting in evolutionary dynamics that might not match those predicted using single species approaches. Recent theories predict that species interactions in diverse systems can influence how component species evolve in response to environmental change. In turn, evolution might have consequences for ecosystem functioning. We used experimental communities of five bacterial species to show that species interactions have a major impact on adaptation to a novel environment in the laboratory. Species in communities diverged in their use of resources compared with the same species in monocultures and evolved to use waste products generated by other species. This generally led to a trade-off between adaptation to the abiotic and biotic components of the environment, such that species evolving in communities had lower growth rates when assayed in the absence of other species. Based on growth assays and on nuclear magnetic resonance (NMR) spectroscopy of resource use, all species evolved more in communities than they did in monocultures. The evolutionary changes had significant repercussions for the functioning of these experimental ecosystems: communities reassembled from isolates that had evolved in polyculture were more productive than those reassembled from isolates that had evolved in monoculture. Our results show that the way in which species adapt to new environments depends critically on the biotic environment of co-occurring species. Moreover, predicting how functioning of complex ecosystems will respond to an environmental change requires knowing how species interactions will evolve.

  3. Affective Patterns in Triadic Family Interactions: Associations with Adolescent Depression

    PubMed Central

    Hollenstein, Tom; Allen, Nicholas; Sheeber, Lisa

    2016-01-01

    Affective family processes are associated with the development of depression during adolescence. However, empirical description of these processes is generally based on examining affect at the individual or dyadic level. The purpose of this study was to examine triadic patterns of affect during parent-adolescent interactions in families with or without a depressed adolescent. We used state space grid analysis to characterize the state of all three actors simultaneously. Compared to healthy controls, triads with depressed adolescents displayed a wider range of affect, demonstrated less predictability of triadic affective sequences, spent more time and returned more quickly to discrepant affective states, and spent less time and returned more slowly to matched affective states, particularly while engaged in a problem-solving interaction. Furthermore, we identified seven unique triadic states in which triads with depressed adolescents spent significantly more time than triads with healthy controls. The present study enhances understanding of family affective processes related to depression by taking a more systemic approach and revealing triadic patterns that go beyond individual and dyadic analyses. PMID:25797844

  4. fMRI Scanner Noise Interaction with Affective Neural Processes

    PubMed Central

    Skouras, Stavros; Gray, Marcus; Critchley, Hugo; Koelsch, Stefan

    2013-01-01

    The purpose of the present study was the investigation of interaction effects between functional MRI scanner noise and affective neural processes. Stimuli comprised of psychoacoustically balanced musical pieces, expressing three different emotions (fear, neutral, joy). Participants (N=34, 19 female) were split into two groups, one subjected to continuous scanning and another subjected to sparse temporal scanning that features decreased scanner noise. Tests for interaction effects between scanning group (sparse/quieter vs continuous/noisier) and emotion (fear, neutral, joy) were performed. Results revealed interactions between the affective expression of stimuli and scanning group localized in bilateral auditory cortex, insula and visual cortex (calcarine sulcus). Post-hoc comparisons revealed that during sparse scanning, but not during continuous scanning, BOLD signals were significantly stronger for joy than for fear, as well as stronger for fear than for neutral in bilateral auditory cortex. During continuous scanning, but not during sparse scanning, BOLD signals were significantly stronger for joy than for neutral in the left auditory cortex and for joy than for fear in the calcarine sulcus. To the authors' knowledge, this is the first study to show a statistical interaction effect between scanner noise and affective processes and extends evidence suggesting scanner noise to be an important factor in functional MRI research that can affect and distort affective brain processes. PMID:24260420

  5. Group Composition Affecting Student Interaction and Achievement: Instructors' Perspectives

    ERIC Educational Resources Information Center

    Lei, Simon A.; Kuestermeyer, Bailey N.; Westmeyer, Kara A.

    2010-01-01

    Multiple research studies have been conducted that focus on various uses of collaborative learning in and out of the classroom in higher education institutions. The purpose of this article is to review previously published literature regarding group composition and how it affects student interaction and achievement. Group composition research has…

  6. Locomotion in Stroke Subjects: Interactions between Unaffected and Affected Sides

    ERIC Educational Resources Information Center

    Kloter, Evelyne; Wirz, Markus; Dietz, Volker

    2011-01-01

    The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm…

  7. Seasonal species interactions minimize the impact of species turnover on the likelihood of community persistence.

    PubMed

    Saavedra, Serguei; Rohr, Rudolf P; Fortuna, Miguel A; Selva, Nuria; Bascompte, Jordi

    2016-04-01

    Many of the observed species interactions embedded in ecological communities are not permanent, but are characterized by temporal changes that are observed along with abiotic and biotic variations. While work has been done describing and quantifying these changes, little is known about their consequences for species coexistence. Here, we investigate the extent to which changes of species composition impact the likelihood of persistence of the predator-prey community in the highly seasonal Białowieza Primeval Forest (northeast Poland), and the extent to which seasonal changes of species interactions (predator diet) modulate the expected impact. This likelihood is estimated extending recent developments on the study of structural stability in ecological communities. We find that the observed species turnover strongly varies the likelihood of community persistence between summer and winter. Importantly, we demonstrate that the observed seasonal interaction changes minimize the variation in the likelihood of persistence associated with species turnover across the year. We find that these community dynamics can be explained as the coupling of individual species to their environment by minimizing both the variation in persistence conditions and the interaction changes between seasons. Our results provide a homeostatic explanation for seasonal species interactions and suggest that monitoring the association of interactions changes with the level of variation in community dynamics can provide a good indicator of the response of species to environmental pressures.

  8. Species-Specific Effects on Ecosystem Functioning Can Be Altered by Interspecific Interactions.

    PubMed

    Clare, David S; Spencer, Matthew; Robinson, Leonie A; Frid, Christopher L J

    2016-01-01

    Biological assemblages are constantly undergoing change, with species being introduced, extirpated and experiencing shifts in their densities. Theory and experimentation suggest that the impacts of such change on ecosystem functioning should be predictable based on the biological traits of the species involved. However, interspecific interactions could alter how species affect functioning, with the strength and sign of interactions potentially depending on environmental context (e.g. homogenous vs. heterogeneous conditions) and the function considered. Here, we assessed how concurrent changes to the densities of two common marine benthic invertebrates, Corophium volutator and Hediste diversicolor, affected the ecological functions of organic matter consumption and benthic-pelagic nutrient flux. Complementary experiments were conducted within homogenous laboratory microcosms and naturally heterogeneous field plots. When the densities of the species were increased within microcosms, interspecific interactions enhanced effects on organic matter consumption and reduced effects on nutrient flux. Trait-based predictions of how each species would affect functioning were only consistently supported when the density of the other species was low. In field plots, increasing the density of either species had a positive effect on organic matter consumption (with no significant interspecific interactions) but no effect on nutrient flux. Our results indicate that species-specific effects on ecosystem functioning can be altered by interspecific interactions, which can be either facilitative (positive) or antagonistic (negative) depending on the function considered. The impacts of biodiversity change may therefore not be predictable based solely on the biological traits of the species involved. Possible explanations for why interactions were detected in microcosms but not in the field are discussed.

  9. Species-Specific Effects on Ecosystem Functioning Can Be Altered by Interspecific Interactions

    PubMed Central

    Spencer, Matthew; Robinson, Leonie A.; Frid, Christopher L. J.

    2016-01-01

    Biological assemblages are constantly undergoing change, with species being introduced, extirpated and experiencing shifts in their densities. Theory and experimentation suggest that the impacts of such change on ecosystem functioning should be predictable based on the biological traits of the species involved. However, interspecific interactions could alter how species affect functioning, with the strength and sign of interactions potentially depending on environmental context (e.g. homogenous vs. heterogeneous conditions) and the function considered. Here, we assessed how concurrent changes to the densities of two common marine benthic invertebrates, Corophium volutator and Hediste diversicolor, affected the ecological functions of organic matter consumption and benthic-pelagic nutrient flux. Complementary experiments were conducted within homogenous laboratory microcosms and naturally heterogeneous field plots. When the densities of the species were increased within microcosms, interspecific interactions enhanced effects on organic matter consumption and reduced effects on nutrient flux. Trait-based predictions of how each species would affect functioning were only consistently supported when the density of the other species was low. In field plots, increasing the density of either species had a positive effect on organic matter consumption (with no significant interspecific interactions) but no effect on nutrient flux. Our results indicate that species-specific effects on ecosystem functioning can be altered by interspecific interactions, which can be either facilitative (positive) or antagonistic (negative) depending on the function considered. The impacts of biodiversity change may therefore not be predictable based solely on the biological traits of the species involved. Possible explanations for why interactions were detected in microcosms but not in the field are discussed. PMID:27812164

  10. Duration of Exposure to Elevated Temperature Affects Competitive Interactions in Juvenile Reef Fishes

    PubMed Central

    Warren, Donald T.; Donelson, Jennifer M.; McCormick, Mark I.; Ferrari, Maud C. O.; Munday, Philip L.

    2016-01-01

    Climate change will affect key ecological processes that structure natural communities, but the outcome of interactions between individuals and species will depend on their thermal plasticity. We tested how short- and long-term exposure to projected future temperatures affects intraspecific and interspecific competitive interactions in two species of coral reef damselfishes. In conspecific contests, juvenile Ambon damselfish, Pomacentrus amboinensis, exhibited no change in aggressive interactions after 4d exposure to higher temperatures. However, after 90d of exposure, fish showed a nonadaptive reduction in aggression at elevated temperatures. Conversely, 4d exposure to higher temperature increased aggression towards conspecifics in the lemon damselfish, Pomacentrus moluccensis. 90d exposure began to reduce this pattern, but overall there was little effect of temperature. Aggression in interspecific contests increased with short-term exposure, but was significantly lower after long-term exposure indicative of acclimation. Our results show how the length of exposure to elevated temperature can affect the outcome of competitive interactions. Furthermore, we illustrate that results from intraspecific contests may not accurately predict interspecific interactions, which will challenge our ability to generalise the effects of warming on competitive interactions. PMID:27736924

  11. Seasonal polyphenism in wing coloration affects species recognition in rubyspot damselflies (Hetaerina spp.).

    PubMed

    Drury, J P; Anderson, C N; Grether, G F

    2015-08-01

    Understanding how phenotypic plasticity evolves and in turn affects the course of evolution is a major challenge in modern biology. By definition, biological species are reproductively isolated, but many animals fail to distinguish between conspecifics and closely related heterospecifics. In some cases, phenotypic plasticity may interfere with species recognition. Here, we document a seasonal polyphenism in the degree of dark wing pigmentation in smoky rubyspot damselflies (Hetaerina titia) - a shift so pronounced that it led early researchers to classify different forms of H. titia as separate species. We further show how the seasonal colour shift impacts species recognition with the sympatric congener Hetaerina occisa. Interspecific aggression (territorial fights) and reproductive interference (mating attempts) are much more frequent early in the year, when H. titia more closely resembles H. occisa, compared to later in the year when the dark phase of H. titia predominates. Using wing colour manipulations of tethered damselflies, we show that the seasonal changes in interspecific interactions are caused not only by the seasonal colour shift but also by shifts in discriminatory behaviour in both species. We also experimentally tested and rejected the hypothesis that learning underlies the behavioural shifts in H. occisa. An alternative hypothesis, which remains to be tested, is that the seasonal polyphenism in H. titia wing coloration has resulted in the evolution of a corresponding seasonal polyphenism in species recognition in H. occisa. This study illustrates one of the many possible ways that plasticity in species recognition cues may influence the evolution of interspecific interactions.

  12. Environmental responses, not species interactions, determine synchrony of dominant species in semiarid grasslands.

    PubMed

    Tredennick, Andrew T; de Mazancourt, Claire; Loreau, Michel; Adler, Peter B

    2017-02-01

    Temporal asynchrony among species helps diversity to stabilize ecosystem functioning, but identifying the mechanisms that determine synchrony remains a challenge. Here, we refine and test theory showing that synchrony depends on three factors: species responses to environmental variation, interspecific interactions, and demographic stochasticity. We then conduct simulation experiments with empirical population models to quantify the relative influence of these factors on the synchrony of dominant species in five semiarid grasslands. We found that the average synchrony of per capita growth rates, which can range from 0 (perfect asynchrony) to 1 (perfect synchrony), was higher when environmental variation was present (0.62) rather than absent (0.43). Removing interspecific interactions and demographic stochasticity had small effects on synchrony. For the dominant species in these plant communities, where species interactions and demographic stochasticity have little influence, synchrony reflects the covariance in species responses to the environment. This article is protected by copyright. All rights reserved.

  13. A preliminary investigation of affective interaction in chronic pain couples.

    PubMed

    Johansen, Ayna Beate; Cano, Annmarie

    2007-11-01

    The objective of this preliminary study was to examine the extent to which affective marital interaction related to depressive symptoms in persons with chronic pain and their spouses and to pain severity in persons with pain. Couples from the community completed self-report surveys and engaged in a videotaped conversation on a topic of mutual disagreement that was coded for three affect types (i.e., anger/contempt, sadness, humor). Humor was positively related to marital satisfaction in both partners. Spouse anger/contempt and sadness were positively related to depressive symptoms in spouses. Several significant interaction effects between couple pain status (i.e., whether one or both partners reported pain) and affect also emerged. Specifically, sadness in the participant designated as the person with pain was associated with greater depressive symptoms and pain severity when only he or she reported pain whereas sadness was related to fewer depressive symptoms and less pain severity when both partners reported pain. The relationships between spouse anger and spouse depressive symptoms and between spouse humor and pain severity in the person with pain were also moderated by couple pain status. These exploratory findings can be interpreted in light of emotion regulation and pain empathy theories. For example, partners who have not experienced pain themselves may fail to empathize with persons in pain, thus preventing effective emotion regulation. When both spouses report chronic pain, expressions of negative affect may instead promote emotion regulation because the affect is experienced with a spouse who may be more empathetic.

  14. Locomotion in stroke subjects: interactions between unaffected and affected sides.

    PubMed

    Kloter, Evelyne; Wirz, Markus; Dietz, Volker

    2011-03-01

    The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm muscles of both sides, with larger amplitudes prior to swing over an obstacle compared with normal swing. In post-stroke subjects, the electromyography responses were stronger on both sides when the tibial nerve of the unaffected leg was stimulated compared with stimulation of the affected leg. This difference was more pronounced when stimuli were applied prior to swing over an obstacle than prior to normal swing. This indicates an impaired processing of afferent input from the affected leg resulting in attenuated and little task-modulated reflex responses in the arm muscles on both sides. In contrast, an afferent volley from the unaffected leg resulted in larger electromyography responses, even in the muscles of the affected arm. Arm muscle activations were stronger during swing over an obstacle than during normal swing, with no difference in electromyography amplitudes between the unaffected and affected sides. It is concluded that the deficits of the affected arm are compensated for by influences from the unaffected side. These observations indicate strong mutual influences between unaffected and affected sides during locomotion of post-stroke subjects, which might be used to optimize rehabilitation approaches.

  15. Competition, not cooperation, dominates interactions among culturable microbial species.

    PubMed

    Foster, Kevin R; Bell, Thomas

    2012-10-09

    Microbial cells secrete numerous enzymes, scavenging molecules, and signals that can promote the growth and survival of other cells around them [1-4]. This observation is consistent with the evolution of cooperation within species [5], and there is now an increasing emphasis on the importance of cooperation between different microbial species [4, 6]. We lack, however, a systematic test of the importance of mutually positive interactions between different species, which is vital for assessing the commonness and importance of cooperative evolution in natural communities. Here, we study the extent of mutually positive interaction among bacterial strains isolated from a common aquatic environment. Using data collected from two independent experiments evaluating community productivity across diversity gradients, we show that (1) in pairwise species combinations, the great majority of interactions are net negative and (2) there is no evidence that strong higher-order positive effects arise when more than two species are mixed together. Our data do not exclude the possibility of positive effects in one direction where one species gains at the expense of another, i.e., predator-prey-like interactions. However, these do not constitute cooperation and our analysis suggests that the typical result of adaptation to other microbial species will be competitive, rather than cooperative, phenotypes.

  16. Relative species abundance of replicator dynamics with sparse interactions

    NASA Astrophysics Data System (ADS)

    Obuchi, Tomoyuki; Kabashima, Yoshiyuki; Tokita, Kei

    2016-11-01

    A theory of relative species abundance on sparsely-connected networks is presented by investigating the replicator dynamics with symmetric interactions. Sparseness of a network involves difficulty in analyzing the fixed points of the equation, and we avoid this problem by treating large self interaction u, which allows us to construct a perturbative expansion. Based on this perturbation, we find that the nature of the interactions is directly connected to the abundance distribution, and some characteristic behaviors, such as multiple peaks in the abundance distribution and all species coexistence at moderate values of u, are discovered in a wide class of the distribution of the interactions. The all species coexistence collapses at a critical value of u, u c , and this collapsing is regarded as a phase transition. To get more quantitative information, we also construct a non-perturbative theory on random graphs based on techniques of statistical mechanics. The result shows those characteristic behaviors are sustained well even for not large u. For even smaller values of u, extinct species start to appear and the abundance distribution becomes rounded and closer to a standard functional form. Another interesting finding is the non-monotonic behavior of diversity, which quantifies the number of coexisting species, when changing the ratio of mutualistic relations Δ . These results are examined by numerical simulations, which show that our theory is exact for the case without extinct species, but becomes less and less precise as the proportion of extinct species grows.

  17. Insufficient sampling to identify species affected by turbine collisions

    USGS Publications Warehouse

    Beston, Julie A.; Diffendorfer, James E.; Loss, Scott

    2015-01-01

    We compared the number of avian species detected and the sampling effort during fatality monitoring at 50 North American wind facilities. Facilities with short intervals between sampling events and high effort detected more species, but many facilities appeared undersampled. Species accumulation curves for 2 wind facilities studied for more than 1 year had yet to reach an asymptote. The monitoring effort that is typically invested is likely inadequate to identify all of the species killed by wind turbines. This may understate impacts for rare species of conservation concern that collide infrequently with turbines but suffer disproportionate consequences from those fatalities. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  18. Insufficient Sampling to Identify Species Affected by Turbine Collisions

    PubMed Central

    Beston, Julie A; Diffendorfer, Jay E; Loss, Scott

    2015-01-01

    We compared the number of avian species detected and the sampling effort during fatality monitoring at 50 North American wind facilities. Facilities with short intervals between sampling events and high effort detected more species, but many facilities appeared undersampled. Species accumulation curves for 2 wind facilities studied for more than 1 year had yet to reach an asymptote. The monitoring effort that is typically invested is likely inadequate to identify all of the species killed by wind turbines. This may understate impacts for rare species of conservation concern that collide infrequently with turbines but suffer disproportionate consequences from those fatalities. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. PMID:25914425

  19. Interactions with heterospecific males do not affect how female Mesocricetus hamsters respond to conspecific males

    PubMed Central

    delBarco-Trillo, Javier; Johnston, Robert E.

    2012-01-01

    Reproductive interference includes any interspecific interaction that reduces the fitness of one or both species involved. There are several types of reproductive interference, but they normally involve the direct cost of interacting or mating with heterospecifics. An indirect cost of interacting with heterospecific individuals is a consequent reduction in successful interactions with conspecifics. We tested the hypothesis that being aggressive towards a heterospecific individual will diminish sexual responses towards conspecifics in later encounters. We used two species of Mesocricetus hamsters (Syrian and Turkish hamsters), whose interspecific interactions have previously been determined. We exposed or both exposed and paired Syrian hamster females with a conspecific or a heterospecific male. Five minutes later, we paired all females with a conspecific male and measured the latency to lordosis, the duration of lordosis and any incidence of aggression. We found that (1) interactions with heterospecific males did not affect how females responded to conspecific males in later encounters and (2) previous pairing of female subjects with either conspecific or heterospecific males promoted a faster sexual response by females in subsequent interactions with conspecific males. Thus, aggressive interactions of Syrian hamster females with heterospecific males, contrary to our initial hypothesis, had a positive effect on subsequent interactions with conspecific males. PMID:23439800

  20. Double species Bose-Einstein condensate with tunable interspecies interactions.

    PubMed

    Thalhammer, G; Barontini, G; De Sarlo, L; Catani, J; Minardi, F; Inguscio, M

    2008-05-30

    We produce Bose-Einstein condensates of two different species, 87Rb and 41K, in an optical dipole trap in proximity of interspecies Feshbach resonances. We discover and characterize two Feshbach resonances, located around 35 and 79 G, by observing the three-body losses and the elastic cross section. The narrower resonance is exploited to create a double species condensate with tunable interactions. Our system opens the way to the exploration of double species Mott insulators and, more in general, of the quantum phase diagram of the two-species Bose-Hubbard model.

  1. Environmental responses, not species interactions, determine synchrony of dominant species in semiarid grasslands

    PubMed Central

    Tredennick, Andrew T.; de Mazancourt, Claire; Loreau, Michel; Adler, Peter B.

    2017-01-01

    Temporal asynchrony among species helps diversity to stabilize ecosystem functioning, but identifying the mechanisms that determine synchrony remains a challenge. Here, we refine and test theory showing that synchrony depends on three factors: species responses to environmental variation, interspecific interactions, and demographic stochasticity. We then conduct simulation experiments with empirical population models to quantify the relative influence of these factors on the synchrony of dominant species in five semiarid grasslands. We found that the average synchrony of per capita growth rates, which can range from 0 (perfect asynchrony) to 1 (perfect synchrony), was higher when environmental variation was present (0.62) rather than absent (0.43). Removing interspecific interactions and demographic stochasticity had small effects on synchrony. For the dominant species in these plant communities, where species interactions and demographic stochasticity have little influence, synchrony reflects the covariance in species’ responses to the environment. PMID:28144939

  2. Pesticide interactions with soils affected by olive oil mill wastewater

    NASA Astrophysics Data System (ADS)

    Keren, Yonatan; Bukhanovsky, Nadezhda; Borisover, Mikhail

    2013-04-01

    Soil pesticide sorption is well known to affect the fate of pesticides, their bioavailability and the potential to contaminate air and water. Soil - pesticide interactions may be strongly influenced by soil organic matter (SOM) and organic matter (OM)-rich soil amendments. One special OM source in soils is related to olive oil production residues that may include both solid and liquid wastes. In the Mediterranean area, the olive oil production is considered as an important field in the agricultural sector. Due to the significant rise in olive oil production, the amount of wastes is growing respectively. Olive oil mill waste water (OMWW) is the liquid byproduct in the so-called "three phase" technological process. Features of OMWW include the high content of fatty aliphatic components and polyphenols and their often-considered toxicity. One way of OMWW disposal is the land spreading, e.g., in olive orchards. The land application of OMWW (either controlled or not) is supposed to affect the multiple soil properties, including hydrophobicity and the potential of soils to interact with pesticides. Therefore, there is both basic and applied interest in elucidating the interactions between organic compounds and soils affected by OMWW. However, little is known about the impact of OMWW - soil interactions on sorption of organic compounds, and specifically, on sorption of agrochemicals. This paper reports an experimental study of sorption interactions of a series of organic compounds including widely used herbicides such as diuron and simazine, in a range of soils that were affected by OMWW (i) historically or (ii) in the controlled land disposal experiments. It is demonstrated that there is a distinct increase in apparent sorption of organic chemicals in soils affected by OMWW. In selected systems, this increase may be explained by increase in SOM content. However, the SOM quality places a role: the rise in organic compound - soil interactions may both exceed the SOM

  3. Relative abundance of an invasive alien plant affects insect-flower interaction networks in Ireland

    NASA Astrophysics Data System (ADS)

    Stout, Jane C.; Casey, Leanne M.

    2014-02-01

    Invasive alien flowering plants may affect native plant pollinator interactions and have knock on impacts on populations of native plants and animals. The magnitude of these impacts, however, may be modified by the relative abundance of the invasive plant and the number of flowers it presents.We tested this by examining the structure of insect-flower interaction networks in six sites with increasing levels of invasion by Rhododendron ponticum in Ireland.Neither flower-visiting insect abundance, species richness nor diversity were related to R. ponticum flower abundance, but the composition of insect communities was. The total number of flowers in a site increased with the relative abundance of R. ponticum flowers but the number of co-flowering native plant species in these sites was low (<6), making interaction networks relatively small.As a result, changes in interaction network properties (connectance, interaction evenness and network level specialisation), which correlated with R. ponticum flower abundance, were a result of the small network size rather than due to changes in the resilience of networks.Overall, we conclude that the impacts of invasive alien plants on native plant-pollinator interactions are not only species specific, but site specific, according to the abundance of flowers produced by both the invasive and the native plants.

  4. Unified spatial scaling of species and their trophic interactions.

    PubMed

    Brose, Ulrich; Ostling, Annette; Harrison, Kateri; Martinez, Neo D

    2004-03-11

    Two largely independent bodies of scaling theory address the quantitative relationships between habitat area, species diversity and trophic interactions. Spatial theory within macroecology addresses how species richness scales with area in landscapes, while typically ignoring interspecific interactions. Complexity theory within community ecology addresses how trophic links scale with species richness in food webs, while typically ignoring spatial considerations. Recent studies suggest unifying these theories by demonstrating how spatial patterns influence food-web structure and vice versa. Here, we follow this suggestion by developing and empirically testing a more unified scaling theory. On the basis of power-law species-area relationships, we develop link-area and non-power-law link-species models that accurately predict how trophic links scale with area and species richness of microcosms, lakes and streams from community to metacommunity levels. In contrast to previous models that assume that species richness alone determines the number of trophic links, these models include the species' spatial distribution, and hence extend the domain of complexity theory to metacommunity scales. This generality and predictive success shows how complexity theory and spatial theory can be unified into a much more general theory addressing new domains of ecology.

  5. Trophic interactions and the relationship between species diversity and ecosystem stability.

    PubMed

    Thébault, Elisa; Loreau, Michel

    2005-10-01

    Several theoretical studies propose that biodiversity buffers ecosystem functioning against environmental fluctuations, but virtually all of these studies concern a single trophic level, the primary producers. Changes in biodiversity also affect ecosystem processes through trophic interactions. Therefore, it is important to understand how trophic interactions affect the relationship between biodiversity and the stability of ecosystem processes. Here we present two models to investigate this issue in ecosystems with two trophic levels. The first is an analytically tractable symmetrical plant-herbivore model under random environmental fluctuations, while the second is a mechanistic ecosystem model under periodic environmental fluctuations. Our analysis shows that when diversity affects net species interaction strength, species interactions--both competition among plants and plant-herbivore interactions--have a strong impact on the relationships between diversity and the temporal variability of total biomass of the various trophic levels. More intense plant competition leads to a stronger decrease or a lower increase in variability of total plant biomass, but plant-herbivore interactions always have a destabilizing effect on total plant biomass. Despite the complexity generated by trophic interactions, biodiversity should still act as biological insurance for ecosystem processes, except when mean trophic interaction strength increases strongly with diversity.

  6. Setting realistic recovery targets for two interacting endangered species, sea otter and northern abalone.

    PubMed

    Chadès, Iadine; Curtis, Janelle M R; Martin, Tara G

    2012-12-01

    Failure to account for interactions between endangered species may lead to unexpected population dynamics, inefficient management strategies, waste of scarce resources, and, at worst, increased extinction risk. The importance of species interactions is undisputed, yet recovery targets generally do not account for such interactions. This shortcoming is a consequence of species-centered legislation, but also of uncertainty surrounding the dynamics of species interactions and the complexity of modeling such interactions. The northern sea otter (Enhydra lutris kenyoni) and one of its preferred prey, northern abalone (Haliotis kamtschatkana), are endangered species for which recovery strategies have been developed without consideration of their strong predator-prey interactions. Using simulation-based optimization procedures from artificial intelligence, namely reinforcement learning and stochastic dynamic programming, we combined sea otter and northern abalone population models with functional-response models and examined how different management actions affect population dynamics and the likelihood of achieving recovery targets for each species through time. Recovery targets for these interacting species were difficult to achieve simultaneously in the absence of management. Although sea otters were predicted to recover, achieving abalone recovery targets failed even when threats to abalone such as predation and poaching were reduced. A management strategy entailing a 50% reduction in the poaching of northern abalone was a minimum requirement to reach short-term recovery goals for northern abalone when sea otters were present. Removing sea otters had a marginally positive effect on the abalone population but only when we assumed a functional response with strong predation pressure. Our optimization method could be applied more generally to any interacting threatened or invasive species for which there are multiple conservation objectives.

  7. Climate change can cause spatial mismatch of trophically interacting species.

    PubMed

    Schweiger, Oliver; Settele, Josef; Kudrna, Otakar; Klotz, Stefan; Kühn, Ingolf

    2008-12-01

    Climate change is one of the most influential drivers of biodiversity. Species-specific differences in the reaction to climate change can become particularly important when interacting species are considered. Current studies have evidenced temporal mismatching of interacting species at single points in space, and recently two investigations showed that species interactions are relevant for their future ranges. However, so far we are not aware that the ranges of interacting species may become substantially spatially mismatched. We developed separate ecological-niche models for a monophagous butterfly (Boloria titania) and its larval host plant (Polygonum bistorta) based on monthly interpolated climate data, land-cover classes, and soil data at a 10'-grid resolution. We show that all of three chosen global-change scenarios, which cover a broad range of potential developments in demography, socio-economics, and technology during the 21st century from moderate to intermediate to maximum change, will result in a pronounced spatial mismatch between future niche spaces of these species. The butterfly may expand considerably its future range (by 124-258%) if the host plant has unlimited dispersal, but it could lose 52-75% of its current range if the host plant is not able to fill its projected ecological niche space, and 79-88% if the butterfly also is assumed to be highly dispersal limited. These findings strongly suggest that climate change has the potential to disrupt trophic interactions because co-occurring species do not necessarily react in a similar manner to global change, having important consequences at ecological and evolutionary time scales.

  8. Conditions Promoting Mycorrhizal Parasitism Are of Minor Importance for Competitive Interactions in Two Differentially Mycotrophic Species

    PubMed Central

    Friede, Martina; Unger, Stephan; Hellmann, Christine; Beyschlag, Wolfram

    2016-01-01

    Interactions of plants with arbuscular mycorrhizal fungi (AMF) may range along a broad continuum from strong mutualism to parasitism, with mycorrhizal benefits received by the plant being determined by climatic and edaphic conditions affecting the balance between carbon costs vs. nutritional benefits. Thus, environmental conditions promoting either parasitism or mutualism can influence the mycorrhizal growth dependency (MGD) of a plant and in consequence may play an important role in plant-plant interactions. In a multifactorial field experiment we aimed at disentangling the effects of environmental and edaphic conditions, namely the availability of light, phosphorus and nitrogen, and the implications for competitive interactions between Hieracium pilosella and Corynephorus canescens for the outcome of the AMF symbiosis. Both species were planted in single, intraspecific and interspecific combinations using a target-neighbor approach with six treatments distributed along a gradient simulating conditions for the interaction between plants and AMF ranking from mutualistic to parasitic. Across all treatments we found mycorrhizal association of H. pilosella being consistently mutualistic, while pronounced parasitism was observed in C. canescens, indicating that environmental and edaphic conditions did not markedly affect the cost:benefit ratio of the mycorrhizal symbiosis in both species. Competitive interactions between both species were strongly affected by AMF, with the impact of AMF on competition being modulated by colonization. Biomass in both species was lowest when grown in interspecific competition, with colonization being increased in the less mycotrophic C. canescens, while decreased in the obligate mycotrophic H. pilosella. Although parasitism-promoting conditions negatively affected MGD in C. canescens, these effects were small as compared to growth decreases related to increased colonization levels in this species. Thus, the lack of plant control over

  9. Conditions Promoting Mycorrhizal Parasitism Are of Minor Importance for Competitive Interactions in Two Differentially Mycotrophic Species.

    PubMed

    Friede, Martina; Unger, Stephan; Hellmann, Christine; Beyschlag, Wolfram

    2016-01-01

    Interactions of plants with arbuscular mycorrhizal fungi (AMF) may range along a broad continuum from strong mutualism to parasitism, with mycorrhizal benefits received by the plant being determined by climatic and edaphic conditions affecting the balance between carbon costs vs. nutritional benefits. Thus, environmental conditions promoting either parasitism or mutualism can influence the mycorrhizal growth dependency (MGD) of a plant and in consequence may play an important role in plant-plant interactions. In a multifactorial field experiment we aimed at disentangling the effects of environmental and edaphic conditions, namely the availability of light, phosphorus and nitrogen, and the implications for competitive interactions between Hieracium pilosella and Corynephorus canescens for the outcome of the AMF symbiosis. Both species were planted in single, intraspecific and interspecific combinations using a target-neighbor approach with six treatments distributed along a gradient simulating conditions for the interaction between plants and AMF ranking from mutualistic to parasitic. Across all treatments we found mycorrhizal association of H. pilosella being consistently mutualistic, while pronounced parasitism was observed in C. canescens, indicating that environmental and edaphic conditions did not markedly affect the cost:benefit ratio of the mycorrhizal symbiosis in both species. Competitive interactions between both species were strongly affected by AMF, with the impact of AMF on competition being modulated by colonization. Biomass in both species was lowest when grown in interspecific competition, with colonization being increased in the less mycotrophic C. canescens, while decreased in the obligate mycotrophic H. pilosella. Although parasitism-promoting conditions negatively affected MGD in C. canescens, these effects were small as compared to growth decreases related to increased colonization levels in this species. Thus, the lack of plant control over

  10. Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species

    PubMed Central

    Kastman, Erik K.; Kamelamela, Noelani; Norville, Josh W.; Cosetta, Casey M.; Dutton, Rachel J.

    2016-01-01

    ABSTRACT Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ. Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes. PMID:27795388

  11. Abundance and phenology patterns of two pond-breeding salamanders determine species interactions in natural populations.

    PubMed

    Anderson, Thomas L; Hocking, Daniel J; Conner, Christopher A; Earl, Julia E; Harper, Elizabeth B; Osbourn, Michael S; Peterman, William E; Rittenhouse, Tracy A G; Semlitsch, Raymond D

    2015-03-01

    Phenology often determines the outcome of interspecific interactions, where early-arriving species often dominate interactions over those arriving later. The effects of phenology on species interactions are especially pronounced in aquatic systems, but the evidence is largely derived from experimental studies. We examined whether differences in breeding phenology between two pond-breeding salamanders (Ambystoma annulatum and A. maculatum) affected metamorph recruitment and demographic traits within natural populations, with the expectation that the fall-breeding A. annulatum would negatively affect the spring-breeding A. maculatum. We monitored populations of each species at five ponds over 4 years using drift fences. Metamorph abundance and survival of A. annulatum were affected by intra- and interspecific processes, whereas metamorph size and date of emigration were primarily influenced by intraspecific effects. Metamorph abundance, snout-vent length, date of emigration and survival for A. maculatum were all predicted by combinations of intra- and interspecific effects, but often showed negative relationships with A. annulatum metamorph traits and abundance. Size and date of metamorphosis were strongly correlated within each species, but in opposite patterns (negative for A. annulatum and positive for A. maculatum), suggesting that the two species use alternative strategies to enhance terrestrial survival and that these factors may influence their interactions. Our results match predictions from experimental studies that suggest recruitment is influenced by intra- and interspecific processes which are determined by phenological differences between species. Incorporating spatiotemporal variability when modeling population dynamics is necessary to understand the importance of phenology in species interactions, especially as shifts in phenology occur under climate change.

  12. Elevated CO2 affects predator-prey interactions through altered performance.

    PubMed

    Allan, Bridie J M; Domenici, Paolo; McCormick, Mark I; Watson, Sue-Ann; Munday, Philip L

    2013-01-01

    Recent research has shown that exposure to elevated carbon dioxide (CO2) affects how fishes perceive their environment, affecting behavioral and cognitive processes leading to increased prey mortality. However, it is unclear if increased mortality results from changes in the dynamics of predator-prey interactions or due to prey increasing activity levels. Here we demonstrate that ocean pCO2 projected to occur by 2100 significantly effects the interactions of a predator-prey pair of common reef fish: the planktivorous damselfish Pomacentrus amboinensis and the piscivorous dottyback Pseudochromis fuscus. Prey exposed to elevated CO2 (880 µatm) or a present-day control (440 µatm) interacted with similarly exposed predators in a cross-factored design. Predators had the lowest capture success when exposed to elevated CO2 and interacting with prey exposed to present-day CO2. Prey exposed to elevated CO2 had reduced escape distances and longer reaction distances compared to prey exposed to present-day CO2 conditions, but this was dependent on whether the prey was paired with a CO2 exposed predator or not. This suggests that the dynamics of predator-prey interactions under future CO2 environments will depend on the extent to which the interacting species are affected and can adapt to the adverse effects of elevated CO2.

  13. Elevated CO2 Affects Predator-Prey Interactions through Altered Performance

    PubMed Central

    Allan, Bridie J. M.; Domenici, Paolo; McCormick, Mark I.; Watson, Sue-Ann; Munday, Philip L.

    2013-01-01

    Recent research has shown that exposure to elevated carbon dioxide (CO2) affects how fishes perceive their environment, affecting behavioral and cognitive processes leading to increased prey mortality. However, it is unclear if increased mortality results from changes in the dynamics of predator-prey interactions or due to prey increasing activity levels. Here we demonstrate that ocean pCO2 projected to occur by 2100 significantly effects the interactions of a predator-prey pair of common reef fish: the planktivorous damselfish Pomacentrus amboinensis and the piscivorous dottyback Pseudochromis fuscus. Prey exposed to elevated CO2 (880 µatm) or a present-day control (440 µatm) interacted with similarly exposed predators in a cross-factored design. Predators had the lowest capture success when exposed to elevated CO2 and interacting with prey exposed to present-day CO2. Prey exposed to elevated CO2 had reduced escape distances and longer reaction distances compared to prey exposed to present-day CO2 conditions, but this was dependent on whether the prey was paired with a CO2 exposed predator or not. This suggests that the dynamics of predator-prey interactions under future CO2 environments will depend on the extent to which the interacting species are affected and can adapt to the adverse effects of elevated CO2. PMID:23484032

  14. Sensory Information and Encounter Rates of Interacting Species

    PubMed Central

    Hein, Andrew M.; McKinley, Scott A.

    2013-01-01

    Most motile organisms use sensory cues when searching for resources, mates, or prey. The searcher measures sensory data and adjusts its search behavior based on those data. Yet, classical models of species encounter rates assume that searchers move independently of their targets. This assumption leads to the familiar mass action-like encounter rate kinetics typically used in modeling species interactions. Here we show that this common approach can mischaracterize encounter rate kinetics if searchers use sensory information to search actively for targets. We use the example of predator-prey interactions to illustrate that predators capable of long-distance directional sensing can encounter prey at a rate proportional to prey density to the power (where is the dimension of the environment) when prey density is low. Similar anomalous encounter rate functions emerge even when predators pursue prey using only noisy, directionless signals. Thus, in both the high-information extreme of long-distance directional sensing, and the low-information extreme of noisy non-directional sensing, encounter rate kinetics differ qualitatively from those derived by classic theory of species interactions. Using a standard model of predator-prey population dynamics, we show that the new encounter rate kinetics derived here can change the outcome of species interactions. Our results demonstrate how the use of sensory information can alter the rates and outcomes of physical interactions in biological systems. PMID:23966847

  15. The vibration of nanosprings affected by van der Waals interactions.

    PubMed

    Zhao, Junhua; Ben, Sudong; Yu, Peishi

    2016-10-01

    The vibration of tightly helical nanosprings affected by van der Waals (vdW) interactions is investigated based on continuum modelling. Explicit solutions are derived to clarify the influence of initial pitch, stiffness and the number of nanosprings on the period, frequency and amplitude of the vibration. Unlike classic linear/nonlinear springs, the waveform of the vibration is always asymmetric for tightly helical nanosprings due to the asymmetry of vdW attraction and repulsion. The at most three equilibrium positions for the nanosprings strongly depend on the deformation due to competition between the vdW interactions and the elastic energy of the nanosprings. This study provides physical insights into the origin of the novel dynamic properties of such nanosprings.

  16. Can the hydrophilicity of functional monomers affect chemical interaction?

    PubMed

    Feitosa, V P; Ogliari, F A; Van Meerbeek, B; Watson, T F; Yoshihara, K; Ogliari, A O; Sinhoreti, M A; Correr, A B; Cama, G; Sauro, S

    2014-02-01

    The number of carbon atoms and/or ester/polyether groups in spacer chains may influence the interaction of functional monomers with calcium and dentin. The present study assessed the chemical interaction and bond strength of 5 standard-synthesized phosphoric-acid ester functional monomers with different spacer chain characteristics, by atomic absorption spectroscopy (AAS), ATR-FTIR, thin-film x-ray diffraction (TF-XRD), scanning electron microscopy (SEM), and microtensile bond strength (μTBS). The tested functional monomers were 2-MEP (two-carbon spacer chain), 10-MDP (10-carbon), 12-MDDP (12-carbon), MTEP (more hydrophilic polyether spacer chain), and CAP-P (intermediate hydrophilicity ester spacer). The intensity of monomer-calcium salt formation measured by AAS differed in the order of 12-MDDP=10-MDP>CAP-P>MTEP>2-MEP. FTIR and SEM analyses of monomer-treated dentin surfaces showed resistance to rinsing for all monomer-dentin bonds, except with 2-MEP. TF-XRD confirmed the weaker interaction of 2-MEP. Highest µTBS was observed for 12-MDDP and 10-MDP. A shorter spacer chain (2-MEP) of phosphate functional monomers induced formation of unstable monomer-calcium salts, and lower chemical interaction and dentin bond strength. The presence of ester or ether groups within longer spacer carbon chains (CAP-P and MTEP) may affect the hydrophilicity, μTBS, and also the formation of monomer-calcium salts.

  17. Corridors affect plants, animals, and their interactions in fragmented landscapes.

    SciTech Connect

    Tewksbury, Joshua, J.; Levey, Douglas, J.; Haddad, Nick, M.; Sargent, Sarah; Orrock, John, L.; Weldon, Aimee; Danielson, Brent, J.; Brinkerhoff, Jory; Damschen, Ellen, I.; Townsend, Patricia

    2002-10-01

    Tewksbury, J.J., D.J. Levey, N.M. Haddad, S. Sargent, J.L. Orrock, A. Weldon, B.J. Danielson, J. Brinkerhoff, E.I. Damschen, and P. Townsend. 2002. Corridors affect plants, animals, and their interactions in fragmented landscapes. PNAS 99(20):12923-12926. Among the most popular strategies for maintaining populations of both plants and animals in fragmented landscapes is to connect isolated patches with thin strips of habitat, called corridors. Corridors are thought to increase the exchange of individuals between habitat patches, promoting genetic exchange and reducing population fluctuations. Empirical studies addressing the effects of corridors have either been small in scale or have ignored confounding effects of increased habitat area created by the presence of a corridor. These methodological difficulties, coupled with a paucity of studies examining the effects of corridors on plants and plant-animal interactions, have sparked debate over the purported value of corridors in conservation planning. We report results of a large-scale experiment that directly address this debate. We demonstrate that corridors not only increase the exchange of animals between patches, but also facilitate two key plant-animal interactions: pollination and seed dispersal. Our results show that the beneficial effects of corridors extend beyond the area they add, and suggest that increased plant and animal movement through corridors will have positive impacts on plant populations and community interactions in fragmented landscapes.

  18. Trait divergence and indirect interactions allow facilitation of congeneric species

    PubMed Central

    Beltrán, Elisa; Valiente-Banuet, Alfonso; Verdú, Miguel

    2012-01-01

    Background Plant facilitation occurs when the presence of a plant (i.e. a nurse plant) modifies the environment, making it more favourable for the establishment and survival of other species (i.e. facilitated plants), which can germinate and grow nearby. Facilitative associations can be maintained or turned into competition as the facilitated seedling grows. According to the competition-relatedness hypothesis that suggests that closely related species tend to compete more, facilitation turns into competition between phylogenetically close species. However, some examples of facilitation between congeneric species, which are supposed to be closely related species, have been found in nature. Scope In this work, some examples of congeneric facilitation and subsequent coexistence are reviewed and an attempt is made to explain those exceptions to the competition-relatedness hypothesis. Conclusions Two mechanisms are proposed that can switch the facilitation–competition balance: trait divergence and indirect interactions. When traits have diverged within the genus, the niche overlap is reduced and competition relaxed, thus allowing the coexistence of congeneric species. The presence of third interplayers (mycorrhizal fungi, seed dispersers, pollinators or pathogens) participating in the interaction between plants can alleviate the competition or enhance the reproduction and allow the coexistence of species that could not coexist in their absence. PMID:22543178

  19. Environmental factors and interactions affecting the temporal abundance of juvenile flatfish in the Thames Estuary

    NASA Astrophysics Data System (ADS)

    Power, M.; Attrill, M. J.; Thomas, R. M.

    2000-05-01

    Samples taken regularly from the intake screens of West Thurrock power station between January 1977 and November 1992 were used to investigate the factors controlling flatfish abundance (flounder: Platichthys flesus; dab: Limanda limanda; plaice: Pleuronectes platessa; sole: Solea solea) in the middle Thames estuary. Most sampled fish were age-0. All species followed regular patterns of seasonal occurrence, had distinctive seasonal abundance peaks and demonstrated only minimal temporal overlap. Multiple-regression models were used to study the relationship between physico-chemical variables, physico-chemical variable interactions, trends and seasonal factors on fluctuations in flatfish sample abundance. Flounder abundance was significantly influenced by temperature, suspended solids, oxygen-flow and oxygen-temperature interactions, trend and seasonal variables. Dab abundance was significantly related to suspended solids, oxygen-flow, oxygen-temperature and flow-chlorinity interactions, Crangon crangon abundance and seasonal variables. Sole abundance was controlled only by seasonal variables, whilst plaice abundance could not be adequately explained by the available physico-chemical data. The combination of variables affecting flatfish abundance indicates species using the estuary were affected by a complex set of events within the estuary. The interactions between routinely measured environmental variables further suggest that estuarine monitoring studies must attempt to understand the nature of possible interactions between variables if an improved understanding of the changes in estuarine fish communities resulting from human activity is to be gained.

  20. Food-web composition affects cross-ecosystem interactions and subsidies.

    PubMed

    Romero, Gustavo Q; Srivastava, Diane S

    2010-09-01

    1. Ecosystems may affect each other through trophic interactions that cross ecosystem boundaries as well as via the transfer of subsidies, but these effects can vary depending on the identity of species involved in the interaction. 2. In this study, we manipulated two terrestrial bromeliad-living spider species (Aglaoctenus castaneus, Corinna gr. rubripes) that have variable hunting modes, to test their individual and combined effects on aquatic invertebrate community structure and ecosystem processes (i.e. decomposition rate and nitrogen cycling). We predicted that these terrestrial predators can affect aquatic invertebrates and nutrient dynamics within water-filled bromeliads. 3. Aglaoctenus spiders reduced the richness, abundance and biomass of aquatic insect larvae via consumptive or non-consumptive effects on ovipositing terrestrial adults, but effects of the two spider species in combination were usually the linear average of their monoculture effects. In contrast, invertebrates with entirely aquatic life cycles were unaffected or facilitated by spiders. Spiders did not affect either net detritivore biomass or the flux of detrital nitrogen to the bromeliad. Instead, Corinna spiders contributed allochthonous nitrogen to bromeliads. 4. Our results provide the novel observations that predators in one ecosystem not only directly reduce taxa whose life cycles cross-ecosystem boundaries, but also indirectly facilitate taxa whose life cycles are entirely within the second ecosystem. This compensatory response between cross-ecosystem and within-ecosystem taxa may have led to an attenuation of top-down effects across ecosystem boundaries. In addition, our results add to a growing consensus that species identity is an important determinant of community structure and ecosystem functioning. Thus, the composition of both terrestrial and aquatic food webs may affect the strength of cross-ecosystem interactions.

  1. Temperature can interact with landscape factors to affect songbird productivity.

    PubMed

    Cox, W Andrew; Thompson, Frank R; Reidy, Jennifer L; Faaborg, John

    2013-04-01

    Increased temperatures and more extreme weather patterns associated with global climate change can interact with other factors that regulate animal populations, but many climate change studies do not incorporate other threats to wildlife in their analyses. We used 20 years of nest-monitoring data from study sites across a gradient of habitat fragmentation in Missouri, USA, to investigate the relative influence of weather variables (temperature and precipitation) and landscape factors (forest cover and edge density) on the number of young produced per nest attempt (i.e., productivity) for three species of songbirds. We detected a strong forest cover × temperature interaction for the Acadian Flycatcher (Empidonax virescens) on productivity. Greater forest cover resulted in greater productivity because of reduced brood parasitism and increased nest survival, whereas greater temperatures reduced productivity in highly forested landscapes because of increased nest predation but had no effect in less forested landscapes. The Indigo Bunting (Passerina cyanea) exhibited a similar pattern, albeit with a marginal forest cover × temperature interaction. By contrast, productivity of the Northern Cardinal (Cardinalis cardinalis) was not influenced by landscape effects or temperature. Our results highlight a potential difficulty of managing wildlife in response to global change such as habitat fragmentation and climate warming, as the habitat associated with the greatest productivity for flycatchers was also that most negatively influenced by high temperatures. The influence of high temperatures on nest predation (and therefore, nest predators) underscores the need to acknowledge the potential complexity of species' responses to climate change by incorporating a more thorough consideration of community ecology in the development of models of climate impacts on wildlife.

  2. Nitric oxide and reactive oxygen species in plant biotic interactions.

    PubMed

    Scheler, Claudia; Durner, Jörg; Astier, Jeremy

    2013-08-01

    Nitric oxide (NO) and reactive oxygen species (ROS) are important signaling molecules in plants. Recent progress has been made in defining their role during plant biotic interactions. Over the last decade, their function in disease resistance has been highlighted and focused a lot of investigations. Moreover, NO and ROS have recently emerged as important players of defense responses after herbivore attacks. Besides their role in plant adaptive response development, NO and ROS have been demonstrated to be involved in symbiotic interactions between plants and microorganisms. Here we review recent data concerning these three sides of NO and ROS functions in plant biotic interactions.

  3. Thiacloprid affects trophic interaction between gammarids and mayflies.

    PubMed

    Englert, D; Bundschuh, M; Schulz, R

    2012-08-01

    Neonicotinoid insecticides like thiacloprid enter agricultural surface waters, where they may affect predator-prey-interactions, which are of central importance for ecosystems as well as the functions these systems provide. The effects of field relevant thiacloprid concentrations on the leaf consumption of Gammarus fossarum (Amphipoda) were assessed over 96 h (n = 13-17) in conjunction with its predation on Baetis rhodani (Ephemeroptera) nymphs. The predation by Gammarus increased significantly at 0.50-1.00 μg/L. Simultaneously, its leaf consumption decreased with increasing thiacloprid concentration. As a consequence of the increased predation at 1.00 μg/L, gammarids' dry weight rose significantly by 15% compared to the control. At 4.00 μg/L, the reduced leaf consumption was not compensated by an increase in predation causing a significantly reduced dry weight of Gammarus (∼20%). These results may finally suggest that thiacloprid adversely affects trophic interactions, potentially translating into alterations in ecosystem functions, like leaf litter breakdown and aquatic-terrestrial subsidies.

  4. Herbivore and predator diversity interactively affect ecosystem properties in an experimental marine community.

    PubMed

    Douglass, James G; Duffy, J Emmett; Bruno, John F

    2008-06-01

    Interacting changes in predator and prey diversity likely influence ecosystem properties but have rarely been experimentally tested. We manipulated the species richness of herbivores and predators in an experimental benthic marine community and measured their effects on predator, herbivore and primary producer performance. Predator composition and richness strongly affected several community and population responses, mostly via sampling effects. However, some predators survived better in polycultures than in monocultures, suggesting complementarity due to stronger intra- than interspecific interactions. Predator effects also differed between additive and substitutive designs, emphasizing that the relationship between diversity and abundance in an assemblage can strongly influence whether and how diversity effects are realized. Changing herbivore richness and predator richness interacted to influence both total herbivore abundance and predatory crab growth, but these interactive diversity effects were weak. Overall, the presence and richness of predators dominated biotic effects on community and ecosystem properties.

  5. The Voice of Emotion across Species: How Do Human Listeners Recognize Animals' Affective States?

    PubMed Central

    Scheumann, Marina; Hasting, Anna S.; Kotz, Sonja A.; Zimmermann, Elke

    2014-01-01

    Voice-induced cross-taxa emotional recognition is the ability to understand the emotional state of another species based on its voice. In the past, induced affective states, experience-dependent higher cognitive processes or cross-taxa universal acoustic coding and processing mechanisms have been discussed to underlie this ability in humans. The present study sets out to distinguish the influence of familiarity and phylogeny on voice-induced cross-taxa emotional perception in humans. For the first time, two perspectives are taken into account: the self- (i.e. emotional valence induced in the listener) versus the others-perspective (i.e. correct recognition of the emotional valence of the recording context). Twenty-eight male participants listened to 192 vocalizations of four different species (human infant, dog, chimpanzee and tree shrew). Stimuli were recorded either in an agonistic (negative emotional valence) or affiliative (positive emotional valence) context. Participants rated the emotional valence of the stimuli adopting self- and others-perspective by using a 5-point version of the Self-Assessment Manikin (SAM). Familiarity was assessed based on subjective rating, objective labelling of the respective stimuli and interaction time with the respective species. Participants reliably recognized the emotional valence of human voices, whereas the results for animal voices were mixed. The correct classification of animal voices depended on the listener's familiarity with the species and the call type/recording context, whereas there was less influence of induced emotional states and phylogeny. Our results provide first evidence that explicit voice-induced cross-taxa emotional recognition in humans is shaped more by experience-dependent cognitive mechanisms than by induced affective states or cross-taxa universal acoustic coding and processing mechanisms. PMID:24621604

  6. Yakima River Species Interactions Studies, Annual Report 1993.

    SciTech Connect

    Pearsons, Todd N.

    1994-12-01

    Species interactions research was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. Data have been collected prior to supplementation to characterize the rainbow trout population, predict the potential interactions that may occur as a result of supplementation, and develop methods to monitor interactions. Major topics of this report are associated with the life history of rainbow trout, interactions experimentation, and methods for sampling. This report is organized into nine chapters with a general introduction preceding the first chapter and a general discussion following the last chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1 and December 31, 1993 in the upper Yakima basin above Roza Dam, however these data were compared to data from previous years to identify preliminary trends and patterns. Major preliminary findings from each of the chapters included in this report are described.

  7. Stochastic changes affect Solanum wild species following autopolyploidization

    PubMed Central

    Carputo, Domenico

    2013-01-01

    Polyploidy is very common within angiosperms, and several studies are in progress to ascertain the effects of early polyploidization at the molecular, physiological, and phenotypic level. Extensive studies are available only in synthetic allopolyploids. By contrast, less is known about the consequences of autopolyploidization. The current study aimed to assess the occurrence and extent of genetic, epigenetic, and anatomical changes occurring after oryzaline-induced polyploidization of Solanum commersonii Dunal and Solanum bulbocastanum Dunal, two diploid (2n=2×=24) potato species widely used in breeding programmes. Microsatellite analysis showed no polymorphisms between synthetic tetraploids and diploid progenitors. By contrast, analysis of DNA methylation levels indicated that subtle alterations at CG and CHG sites were present in tetraploids of both species. However, no change occurred concurrently in all tetraploids analysed with respect to their diploid parent, revealing a stochastic trend in the changes observed. The morpho-anatomical consequences of polyploidization were studied in leaf main veins and stomata. With only a few exceptions, analyses showed no clear superiority of tetraploids in terms of leaf thickness and area, vessel number, lumen size and vessel wall thickness, stomata pore length and width, guard cell width, and stomatal density compared with their diploid progenitors. These results are consistent with the hypothesis that there are no traits systematically associated with autopolyploidy. PMID:23307917

  8. Species interactions and the structure of complex communication networks

    PubMed Central

    Tobias, Joseph A.; Planqué, Robert; Cram, Dominic L.; Seddon, Nathalie

    2014-01-01

    A universal challenge faced by animal species is the need to communicate effectively against a backdrop of heterospecific signals. It is often assumed that this need results in signal divergence to minimize interference among community members, yet previous support for this idea is mixed, and few studies have tested the opposing hypothesis that interactions among competing species promote widespread convergence in signaling regimes. Using a null model approach to analyze acoustic signaling in 307 species of Amazonian birds, we show that closely related lineages signal together in time and space and that acoustic signals given in temporal or spatial proximity are more similar in design than expected by chance. These results challenge the view that multispecies choruses are structured by temporal, spatial, or acoustic partitioning and instead suggest that social communication between competing species can fundamentally organize signaling assemblages, leading to the opposite pattern of clustering in signals and signaling behavior. PMID:24395769

  9. Yakima River Species Interactions Studies, Annual Report 2000.

    SciTech Connect

    Pearsons, Todd N.

    2001-12-01

    Species interactions research and monitoring was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the ninth of a series of progress reports that address species interactions research and supplementation monitoring of fishes in the Yakima River basin. Data have been collected prior to supplementation to characterize the ecology and demographics of non-target taxa (NTT) and target taxon, and develop methods to monitor interactions and supplementation success. Major topics of this report are associated with the chronology of ecological interactions that occur throughout a supplementation program, implementing NTT monitoring prescriptions for detecting potential impacts of hatchery supplementation, hatchery fish interactions, and monitoring fish predation indices. This report is organized into four chapters, with a general introduction preceding the first chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1, 2000 and December 31, 2000 in the Yakima basin, however these data were compared to data from previous years to identify preliminary trends and patterns. Summaries of each of the chapters included in this report are described.

  10. Yakima River Species Interactions Studies, Annual Report 1994.

    SciTech Connect

    Pearsons, Todd N.

    1996-09-01

    Species interactions research was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the fifth of a series of annual reports that address species interactions research and pre-facility monitoring of fishes in the upper Yakima River basin. Data have been collected prior to supplementation to characterize the rainbow trout and other fish populations such as steelhead and spring chinook salmon, predict the potential interactions that may occur as a result of supplementation, and develop methods to monitor interactions. Major topics of this report are associated with the life history of rainbow trout, interactions experimentation, and methods for sampling. This report is organized into two chapters followed by seven ''updates'' with a general introduction preceding the first chapter and a general discussion following the last update. An appendix follows the general discussion. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1 and December 31, 1994 in the upper Yakima basin above Roza Dam, however these data were compared to data from previous years to identify preliminary trends and patterns. Major preliminary findings from each of the chapters included in this report are described.

  11. Species specificity in avian sperm:perivitelline interaction.

    PubMed

    Stewart, Sarah G; Bausek, Nina; Wohlrab, Franz; Schneider, Wolfgang J; Janet Horrocks, A; Wishart, Graham J

    2004-04-01

    The interaction of chicken spermatozoa with the inner perivitelline layer from different avian species in vitro during a 5 min co-incubation was measured as the number of points of hydrolysis produced per unit area of inner perivitelline layer. The average degree of interaction, as a proportion of that between chicken spermatozoa and their homologous inner perivitelline layer, was: equal to or greater than 100% within Galliformes (chicken, turkey, quail, pheasant, peafowl and guineafowl); 44% within Anseriformes (goose, duck); and less than 30% in Passeriformes (Zebra Finch) and Columbiformes (collared-dove). The homologue of the putative chicken sperm-binding proteins, chicken ZP1 and ZP3, were identified by Western blotting with anti-chicken ZP1/ZP3 antibody in the perivitelline layers of all species. The functional cross-reactivity between chicken spermatozoa and heterologous inner perivitelline layer appeared to be linked to known phylogenetic distance between the species, although it was not related to the relative affinity of the different ZP3 homologues for anti-chicken ZP3. This work demonstrates that sperm interaction with the egg investment does not represent such a stringent species-specific barrier in birds as it does in mammals and marine invertebrates. This may be a factor in the frequency of hybrid production in birds.

  12. Fuel breaks affect nonnative species abundance in Californian plant communities

    USGS Publications Warehouse

    Merriam, K.E.; Keeley, J.E.; Beyers, J.L.

    2006-01-01

    We evaluated the abundance of nonnative plants on fuel breaks and in adjacent untreated areas to determine if fuel treatments promote the invasion of nonnative plant species. Understanding the relationship between fuel treatments and nonnative plants is becoming increasingly important as federal and state agencies are currently implementing large fuel treatment programs throughout the United States to reduce the threat of wildland fire. Our study included 24 fuel breaks located across the State of California. We found that nonnative plant abundance was over 200% higher on fuel breaks than in adjacent wildland areas. Relative nonnative cover was greater on fuel breaks constructed by bulldozers (28%) than on fuel breaks constructed by other methods (7%). Canopy cover, litter cover, and duff depth also were significantly lower on fuel breaks constructed by bulldozers, and these fuel breaks had significantly more exposed bare ground than other types of fuel breaks. There was a significant decline in relative nonnative cover with increasing distance from the fuel break, particularly in areas that had experienced more numerous fires during the past 50 years, and in areas that had been grazed. These data suggest that fuel breaks could provide establishment sites for nonnative plants, and that nonnatives may invade surrounding areas, especially after disturbances such as fire or grazing. Fuel break construction and maintenance methods that leave some overstory canopy and minimize exposure of bare ground may be less likely to promote nonnative plants. ?? 2006 by the Ecological Society of America.

  13. Noise pollution changes avian communities and species interactions.

    PubMed

    Francis, Clinton D; Ortega, Catherine P; Cruz, Alexander

    2009-08-25

    Humans have drastically changed much of the world's acoustic background with anthropogenic sounds that are markedly different in pitch and amplitude than sounds in most natural habitats. This novel acoustic background may be detrimental for many species, particularly birds. We evaluated conservation concerns that noise limits bird distributions and reduces nesting success via a natural experiment to isolate the effects of noise from confounding stimuli and to control for the effect of noise on observer detection biases. We show that noise alone reduces nesting species richness and leads to different avian communities. Contrary to expectations, noise indirectly facilitates reproductive success of individuals nesting in noisy areas as a result of the disruption of predator-prey interactions. The higher reproductive success for birds within noisy habitats may be a previously unrecognized factor contributing to the success of urban-adapted species and the loss of birds less tolerant of noise. Additionally, our findings suggest that noise can have cascading consequences for communities through altered species interactions. Given that noise pollution is becoming ubiquitous throughout much of the world, knowledge of species-specific responses to noise and the cumulative effects of these novel acoustics may be crucial to understanding and managing human-altered landscapes.

  14. Yakima River Species Interactions Studies Annual Report, FY 1990.

    SciTech Connect

    Hindman, James N.

    1991-02-01

    Studies of species interactions were implemented to address concerns about the possible effects of supplementation (with anadromous species) on resident fish populations in the upper Yakima River basin. The current study objectives include collection of baseline information on the fish populations in the upper Yakima River and associated tributaries. As part of this baseline phase, spawning surveys of the upper Yakima River and thirteen selected tributaries between Roza and Keechelus dams were initiated during the spring of 1990. This report summarizes the results of field activities conducted from December, 1989 to June, 1990.

  15. Dynamics of species interaction strength in space, time and with developmental stage.

    PubMed

    Kordas, Rebecca L; Dudgeon, Steve

    2011-06-22

    Quantifying species interaction strengths enhances prediction of community dynamics, but variability in the strength of species interactions in space and time complicates accurate prediction. Interaction strengths can vary in response to density, indirect effects, priority effects or a changing environment, but the mechanism(s) causing direction and magnitudes of change are often unclear. We designed an experiment to characterize how environmental factors influence the direction and the strength of priority effects between sessile species. We estimated per capita non-trophic effects of barnacles (Semibalanus balanoides) on newly settled germlings of the fucoid, Ascophyllum nodosum, in the presence and absence of consumers in experiments on rocky shores throughout the Gulf of Maine, USA. Per capita effects on germlings varied among environments and barnacle life stages, and these interaction strengths were largely unaltered by changing consumer abundance. Whereas previous evidence shows adult barnacles facilitate fucoids, here, we show that recent settlers and established juveniles initially compete with germlings. As barnacles mature, they switch to become facilitators of fucoids. Consumers caused variable mortality of germlings through time comparable to that from competition. Temporally variable effects of interactors (e.g. S. balanoides), or spatial variation in their population structure, in different regions differentially affect target populations (e.g. A. nodosum). This may affect abundance of critical stages and the resilience of target species to environmental change in different geographical regions.

  16. Dynamics of species interaction strength in space, time and with developmental stage

    PubMed Central

    Kordas, Rebecca L.; Dudgeon, Steve

    2011-01-01

    Quantifying species interaction strengths enhances prediction of community dynamics, but variability in the strength of species interactions in space and time complicates accurate prediction. Interaction strengths can vary in response to density, indirect effects, priority effects or a changing environment, but the mechanism(s) causing direction and magnitudes of change are often unclear. We designed an experiment to characterize how environmental factors influence the direction and the strength of priority effects between sessile species. We estimated per capita non-trophic effects of barnacles (Semibalanus balanoides) on newly settled germlings of the fucoid, Ascophyllum nodosum, in the presence and absence of consumers in experiments on rocky shores throughout the Gulf of Maine, USA. Per capita effects on germlings varied among environments and barnacle life stages, and these interaction strengths were largely unaltered by changing consumer abundance. Whereas previous evidence shows adult barnacles facilitate fucoids, here, we show that recent settlers and established juveniles initially compete with germlings. As barnacles mature, they switch to become facilitators of fucoids. Consumers caused variable mortality of germlings through time comparable to that from competition. Temporally variable effects of interactors (e.g. S. balanoides), or spatial variation in their population structure, in different regions differentially affect target populations (e.g. A. nodosum). This may affect abundance of critical stages and the resilience of target species to environmental change in different geographical regions. PMID:21106597

  17. Polyphenoloxidase Silencing Affects Latex Coagulation in Taraxacum Species1[W

    PubMed Central

    Wahler, Daniela; Gronover, Christian Schulze; Richter, Carolin; Foucu, Florence; Twyman, Richard M.; Moerschbacher, Bruno M.; Fischer, Rainer; Muth, Jost; Prüfer, Dirk

    2009-01-01

    Latex is the milky sap that is found in many different plants. It is produced by specialized cells known as laticifers and can comprise a mixture of proteins, carbohydrates, oils, secondary metabolites, and rubber that may help to prevent herbivory and protect wound sites against infection. The wound-induced browning of latex suggests that it contains one or more phenol-oxidizing enzymes. Here, we present a comprehensive analysis of the major latex proteins from two dandelion species, Taraxacum officinale and Taraxacum kok-saghyz, and enzymatic studies showing that polyphenoloxidase (PPO) is responsible for latex browning. Electrophoretic analysis and amino-terminal sequencing of the most abundant proteins in the aqueous latex fraction revealed the presence of three PPO-related proteins generated by the proteolytic cleavage of a single precursor (pre-PPO). The laticifer-specific pre-PPO protein contains a transit peptide that can target reporter proteins into chloroplasts when constitutively expressed in dandelion protoplasts, perhaps indicating the presence of structures similar to plastids in laticifers, which lack genuine chloroplasts. Silencing the PPO gene by constitutive RNA interference in transgenic plants reduced PPO activity compared with wild-type controls, allowing T. kok-saghyz RNA interference lines to expel four to five times more latex than controls. Latex fluidity analysis in silenced plants showed a strong correlation between residual PPO activity and the coagulation rate, indicating that laticifer-specific PPO plays a major role in latex coagulation and wound sealing in dandelions. In contrast, very little PPO activity is found in the latex of the rubber tree Hevea brasiliensis, suggesting functional divergence of latex proteins during plant evolution. PMID:19605551

  18. Polyphenoloxidase silencing affects latex coagulation in Taraxacum species.

    PubMed

    Wahler, Daniela; Gronover, Christian Schulze; Richter, Carolin; Foucu, Florence; Twyman, Richard M; Moerschbacher, Bruno M; Fischer, Rainer; Muth, Jost; Prüfer, Dirk

    2009-09-01

    Latex is the milky sap that is found in many different plants. It is produced by specialized cells known as laticifers and can comprise a mixture of proteins, carbohydrates, oils, secondary metabolites, and rubber that may help to prevent herbivory and protect wound sites against infection. The wound-induced browning of latex suggests that it contains one or more phenol-oxidizing enzymes. Here, we present a comprehensive analysis of the major latex proteins from two dandelion species, Taraxacum officinale and Taraxacum kok-saghyz, and enzymatic studies showing that polyphenoloxidase (PPO) is responsible for latex browning. Electrophoretic analysis and amino-terminal sequencing of the most abundant proteins in the aqueous latex fraction revealed the presence of three PPO-related proteins generated by the proteolytic cleavage of a single precursor (pre-PPO). The laticifer-specific pre-PPO protein contains a transit peptide that can target reporter proteins into chloroplasts when constitutively expressed in dandelion protoplasts, perhaps indicating the presence of structures similar to plastids in laticifers, which lack genuine chloroplasts. Silencing the PPO gene by constitutive RNA interference in transgenic plants reduced PPO activity compared with wild-type controls, allowing T. kok-saghyz RNA interference lines to expel four to five times more latex than controls. Latex fluidity analysis in silenced plants showed a strong correlation between residual PPO activity and the coagulation rate, indicating that laticifer-specific PPO plays a major role in latex coagulation and wound sealing in dandelions. In contrast, very little PPO activity is found in the latex of the rubber tree Hevea brasiliensis, suggesting functional divergence of latex proteins during plant evolution.

  19. Interactions between dietary boron and thiamine affect lipid metabolism

    SciTech Connect

    Herbel, J.L.; Hunt, C.D. )

    1991-03-15

    An experiment was designed to test the hypothesis that dietary boron impacts upon the function of various coenzymes involved in energy metabolism. In a 2 {times} 7 factorially-arranged experiment, weanling, vitamin D{sub 3}-deprived rats were fed a ground corn-casein-corn oil based diet supplemented with 0 or 2 mg boron/kg and 50% of the requirement for thiamine (TM), riboflavin (RF), pantothenic acid (PA) or pyridoxine (PX); 0% for folic acid (FA) or nicotinic acid (NA). All vitamins were supplemented in adequate amounts in the control diet. At 8 weeks of age, the TM dietary treatment was the one most affected by supplemental dietary boron (SDB). In rats that were fed 50% TM, SDB increased plasma concentrations of triglyceride (TG) and activity of alanine transaminase (ALT), and the liver to body weight (L/B) ratio. However, in the SDB animals, adequate amounts of TM decreased the means of those variables to near that observed in non-SDB rats fed 50% TM. The findings suggest that an interaction between dietary boron and TM affects lipid metabolism.

  20. Interactions between Artificial Gravity, the Affected Physiological Systems, and Nutrition

    NASA Technical Reports Server (NTRS)

    Heer, Martina; Baecker, Nathalie; Zwart, Sara; Smith, Scott

    2006-01-01

    Malnutrition, either by insufficient supply of some nutrients or by overfeeding, has a profound effect on the health of an organism. Therefore, optimal nutrition is a necessity in normal gravity on Earth, in microgravity, and when applying artificial gravity to the human system. Reduced physical activity, such as observed in microgravity or bed rest, has an effect on many physiological systems, such as the cardiovascular, musculoskeletal, immune, and body fluids regulation systems. There is currently no countermeasure that is effective to counteract both the cardiovascular and musculoskeletal deconditioning when applied for a short duration (see Chapter 1). Artificial gravity therefore seems the simplest physiological approach to keep these systems intact. The application of intermittent daily dose of artificial gravity by means of centrifugation has often been proposed as a potential countermeasure against the physiological deconditioning induced by spaceflight. However, neither the optimal gravity level, nor its optimal duration of exposure have been enough studied to recommend a validated, effective, and efficient artificial gravity application. As discussed in previous chapters, artificial gravity has a very high potential to counteract any changes caused by reduced physical activity. The nutrient supply, which ideally should match the actual needs, will interact with these changes and therefore has also to be taken into account. This chapter reviews the potential interactions between these nutrients (energy intake, vitamins, minerals) and the other physiological systems affected by artificial gravity generated by an on-board short-radius centrifuge.

  1. Yakima River Species Interactions Studies, Annual Report 1999.

    SciTech Connect

    Pearsons, Todd N.

    2001-06-01

    Species interactions research and monitoring was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the eighth of a series of progress reports that address species interactions research and pre-supplementation monitoring of fishes in the Yakima River basin. Data have been collected prior to supplementation to characterize the ecology and demographics of non-target taxa (NTT) and target taxon, and develop methods to monitor interactions and supplementation success. Major topics of this report are associated with implementing NTT monitoring prescriptions for detecting potential impacts of hatchery supplementation, hatchery fish interactions, and monitoring fish predation indices. This report is organized into four chapters, with a general introduction preceding the first chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1, 1998 and December 31, 1999 in the Yakima basin, however these data were compared to data from previous years to identify preliminary trends and patterns.

  2. What Makes Sports Fans Interactive? Identifying Factors Affecting Chat Interactions in Online Sports Viewing

    PubMed Central

    Yeo, Jaeryong; Lee, Juyeong

    2016-01-01

    Sports fans are able to watch games from many locations using TV services while interacting with other fans online. In this paper, we identify the factors that affect sports viewers’ online interactions. Using a large-scale dataset of more than 25 million chat messages from a popular social TV site for baseball, we extract various game-related factors, and investigate the relationships between these factors and fans’ interactions using a series of multiple regression analyses. As a result, we identify several factors that are significantly related to viewer interactions. In addition, we determine that the influence of these factors varies according to the user group; i.e., active vs. less active users, and loyal vs. non-loyal users. PMID:26849568

  3. What Makes Sports Fans Interactive? Identifying Factors Affecting Chat Interactions in Online Sports Viewing.

    PubMed

    Ko, Minsam; Yeo, Jaeryong; Lee, Juyeong; Lee, Uichin; Jang, Young Jae

    2016-01-01

    Sports fans are able to watch games from many locations using TV services while interacting with other fans online. In this paper, we identify the factors that affect sports viewers' online interactions. Using a large-scale dataset of more than 25 million chat messages from a popular social TV site for baseball, we extract various game-related factors, and investigate the relationships between these factors and fans' interactions using a series of multiple regression analyses. As a result, we identify several factors that are significantly related to viewer interactions. In addition, we determine that the influence of these factors varies according to the user group; i.e., active vs. less active users, and loyal vs. non-loyal users.

  4. Consumer species richness and nutrients interact in determining producer diversity

    PubMed Central

    Groendahl, Sophie; Fink, Patrick

    2017-01-01

    While it is crucial to understand the factors that determine the biodiversity of primary producer communities, the relative importance of bottom-up and top-down control factors is still poorly understood. Using freshwater benthic algal communities in the laboratory as a model system, we find an unimodal relationship between nutrient availability and producer diversity, and that increasing number of consumer species increases producer diversity, but overall grazing decreases algal biodiversity. Interestingly, these two factors interact strongly in determining producer diversity, as an increase in nutrient supply diminishes the positive effect of consumer species richness on producer biodiversity. This novel and thus-far overlooked interaction of bottom-up and top-down control mechanisms of biodiversity may have a pronounced impact on ecosystem functioning and thus have repercussions for the fields of biodiversity conservation and restoration. PMID:28303953

  5. Construction of analytically solvable models for interacting species. [biological species competition

    NASA Technical Reports Server (NTRS)

    Rosen, G.

    1976-01-01

    The basic form of a model representation for systems of n interacting biological species is a set of essentially nonlinear autonomous ordinary differential equations. A generic canonical expression for the rate functions in the equations is reported which permits the analytical general solution to be obtained by elementary computation. It is shown that a general analytical solution is directly obtainable for models where the rate functions are prescribed by the generic canonical expression from the outset. Some illustrative examples are given which demonstrate that the generic canonical expression can be used to construct analytically solvable models for two interacting species with limit-cycle dynamics as well as for a three-species interdependence.

  6. Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change

    USGS Publications Warehouse

    McCluney, Kevin E.; Belnap, Jayne; Collins, Scott L.; González, Angélica L.; Hagen, Elizabeth M.; Holland, J. Nathaniel; Kotler, Burt P.; Maestre, Fernando T.; Smith, Stanley D.; Wolf, Blair O.

    2012-01-01

    Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts

  7. Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change.

    PubMed

    McCluney, Kevin E; Belnap, Jayne; Collins, Scott L; González, Angélica L; Hagen, Elizabeth M; Nathaniel Holland, J; Kotler, Burt P; Maestre, Fernando T; Smith, Stanley D; Wolf, Blair O

    2012-08-01

    Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts

  8. Yakima River Species Interactions Studies, Annual Report 2002.

    SciTech Connect

    Pearsons, Todd N.

    2003-05-01

    This report is intended to satisfy two concurrent needs: (1) provide a contract deliverable from the Washington Department of Fish and Wildlife (WDFW) to the Bonneville Power Administration (BPA), with emphasis on identification of salient results of value to ongoing Yakima/Klickitat Fisheries Project (YKFP) planning, and (2) summarize results of research that have broader scientific relevance. This is the eleventh of a series of progress reports that address species interactions research and supplementation monitoring of fishes in response to supplementation of salmon and steelhead in the upper Yakima River basin. This progress report summarizes data collected between January 1, 2002 and December 31, 2002. These data were compared to findings from previous years to identify general trends and make preliminary comparisons. Interactions between fish produced as part of the YKFP, termed target species or stocks, and other species or stocks (non-target taxa) may alter the population status of non-target species or stocks. This may occur through a variety of mechanisms, such as competition, predation, and interbreeding. Furthermore, the success of a supplementation program may be limited by strong ecological interactions such as predation or competition. Our work has adapted to new information needs as the YKFP has evolved. Initially, our work focused on interactions between anadromous steelhead and resident rainbow trout (for explanation see Pearsons et al. 1993), then interactions between spring chinook salmon and rainbow trout, and recently interactions between spring chinook salmon and highly valued nontarget taxa (NTT; e.g., bull trout); and interactions between strong interactor taxa (e.g., those that may strongly influence the abundance of spring chinook salmon; e.g., smallmouth bass) and spring chinook salmon. The change in emphasis to spring chinook salmon has largely been influenced by the shift in the target species planned for supplementation (Bonneville

  9. Shifts in bacterial communities of two caribbean reef-building coral species affected by white plague disease

    PubMed Central

    Cárdenas, Anny; Rodriguez-R, Luis M; Pizarro, Valeria; Cadavid, Luis F; Arévalo-Ferro, Catalina

    2012-01-01

    Coral reefs are deteriorating at an alarming rate mainly as a consequence of the emergence of coral diseases. The white plague disease (WPD) is the most prevalent coral disease in the southwestern Caribbean, affecting dozens of coral species. However, the identification of a single causal agent has proved problematic. This suggests more complex etiological scenarios involving alterations in the dynamic interaction between environmental factors, the coral immune system and the symbiotic microbial communities. Here we compare the microbiome of healthy and WPD-affected corals from the two reef-building species Diploria strigosa and Siderastrea siderea collected at the Tayrona National Park in the Caribbean of Colombia. Microbiomes were analyzed by combining culture-dependent methods and pyrosequencing of 16S ribosomal DNA (rDNA) V5-V6 hypervariable regions. A total of 20 410 classifiable 16S rDNA sequences reads were obtained including all samples. No significant differences in operational taxonomic unit diversity were found between healthy and affected tissues; however, a significant increase of Alphaproteobacteria and a concomitant decrease in the Beta- and Gammaproteobacteria was observed in WPD-affected corals of both species. Significant shifts were also observed in the orders Rhizobiales, Caulobacteriales, Burkholderiales, Rhodobacterales, Aleteromonadales and Xanthomonadales, although they were not consistent between the two coral species. These shifts in the microbiome structure of WPD-affected corals suggest a loss of community-mediated growth control mechanisms on bacterial populations specific for each holobiont system. PMID:21955993

  10. Host-Parasite Interactions in Some Fish Species

    PubMed Central

    Khan, R. A.

    2012-01-01

    Host-parasite interactions are complex, compounded by factors that are capable of shifting the balance in either direction. The host's age, behaviour, immunological status, and environmental change can affect the association that is beneficial to the host whereas evasion of the host's immune response favours the parasite. In fish, some infections that induce mortality are age and temperature dependent. Environmental change, especially habitat degradation by anthropogenic pollutants and oceanographic alterations induced by climatic, can influence parasitic-host interaction. The outcome of these associations will hinge on susceptibility and resistance. PMID:22900144

  11. Competing species in a changing climate: effects of recruitment disturbances on two interacting barnacle species.

    PubMed

    Svensson, Carl Johan; Johansson, Emmeli; Aberg, Per

    2006-05-01

    1. The climate is changing and data-based simulation models can be a valuable tool for predicting population response to such changes and investigate the mechanisms of population change. In this study, a data-based two-species matrix model was constructed to explore the possible effects of elevated sea surface temperature (i.e. climate change) on the interaction between open populations of the south Atlantic barnacle species Chthamalus montagui and the boreal species Semibalanus balanoides in the north-east Atlantic. 2. First, the model was used to perform an elasticity analysis to determine the relative importance of recruitment and survival in the interaction. Further, three scenarios of changes in recruitment, related to climate change, were investigated with model simulations: (i) increased frequencies of low recruitment for S. balanoides; (ii) increased frequencies of high recruitment for C. montagui; (iii) a combination of (i) and (ii). 3. Model simulations showed that in present environmental conditions, S. balanoides occupied most of the space and dominated the interaction through high recruitment and survival. These results matched independent field observations, which validated the model for further analyses. 4. The elasticity analyses showed that although free space was available there was competition for space during recruitment intervals. It was also shown that both populations were sensitive to changes in recruitment. 5. Introducing the three scenarios of recruitment disturbances led to large changes in species abundance and free space. The most significant changes were found when scenario (i) and (ii) were combined, producing a shift in species dynamics towards C. montagui dominance. This demonstrates that recruitment can be an important mechanism in the interaction between populations and that the population response to changes in recruitment depends on the added response of interacting species. 6. In a more general context, this model shows that

  12. From facilitation to competition: temperature-driven shift in dominant plant interactions affects population dynamics in seminatural grasslands.

    PubMed

    Olsen, Siri L; Töpper, Joachim P; Skarpaas, Olav; Vandvik, Vigdis; Klanderud, Kari

    2016-05-01

    Biotic interactions are often ignored in assessments of climate change impacts. However, climate-related changes in species interactions, often mediated through increased dominance of certain species or functional groups, may have important implications for how species respond to climate warming and altered precipitation patterns. We examined how a dominant plant functional group affected the population dynamics of four co-occurring forb species by experimentally removing graminoids in seminatural grasslands. Specifically, we explored how the interaction between dominants and subordinates varied with climate by replicating the removal experiment across a climate grid consisting of 12 field sites spanning broad-scale temperature and precipitation gradients in southern Norway. Biotic interactions affected population growth rates of all study species, and the net outcome of interactions between dominants and subordinates switched from facilitation to competition with increasing temperature along the temperature gradient. The impacts of competitive interactions on subordinates in the warmer sites could primarily be attributed to reduced plant survival. Whereas the response to dominant removal varied with temperature, there was no overall effect of precipitation on the balance between competition and facilitation. Our findings suggest that global warming may increase the relative importance of competitive interactions in seminatural grasslands across a wide range of precipitation levels, thereby favouring highly competitive dominant species over subordinate species. As a result, seminatural grasslands may become increasingly dependent on disturbance (i.e. traditional management such as grazing and mowing) to maintain viable populations of subordinate species and thereby biodiversity under future climates. Our study highlights the importance of population-level studies replicated under different climatic conditions for understanding the underlying mechanisms of climate

  13. Yakima River Species Interactions Studies, Annual Report 2001.

    SciTech Connect

    Pearsons, Todd N.

    2002-05-01

    Species interactions research and monitoring was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the tenth of a series of progress reports that address species interactions research and supplementation monitoring of fishes in the Yakima River basin. Data have been collected before and during supplementation to characterize the ecology and demographics of non-target taxa (NTT) and target taxon, and to monitor interactions and supplementation success. Major topics of this report are associated with implementing NTT monitoring prescriptions for detecting potential impacts of hatchery supplementation, and monitoring fish predation indices. This report is organized into two chapters, with a general introduction preceding the first chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1, 2001 and December 31, 2001 in the Yakima basin, however these data were compared to data from previous years to identify preliminary trends and patterns.

  14. Yakima River Species Interactions Studies, Annual Report 1998.

    SciTech Connect

    Pearsons, Todd N.

    1999-12-01

    Species interactions research and monitoring was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the seventh of a series of progress reports that address species interactions research and pre-supplementation monitoring of fishes in the Yakima River basin. Data have been collected prior to supplementation to characterize the ecology and demographics of non-target taxa (NTT) and target taxon, and develop methods to monitor interactions and supplementation success. Major topics of this report are associated with monitoring potential impacts to support adaptive management of NTT and baseline monitoring of fish predation indices on spring chinook salmon smolts. This report is organized into three chapters, with a general introduction preceding the first chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1, 1998 and December 31, 1998 in the Yakima basin, however these data were compared to data from previous years to identify preliminary trends and patterns.

  15. Cytonuclear interactions affect adaptive traits of the annual plant Arabidopsis thaliana in the field

    PubMed Central

    Roux, Fabrice; Mary-Huard, Tristan; Barillot, Elise; Wenes, Estelle; Botran, Lucy; Durand, Stéphanie; Villoutreix, Romain; Martin-Magniette, Marie-Laure; Camilleri, Christine; Budar, Françoise

    2016-01-01

    Although the contribution of cytonuclear interactions to plant fitness variation is relatively well documented at the interspecific level, the prevalence of cytonuclear interactions at the intraspecific level remains poorly investigated. In this study, we set up a field experiment to explore the range of effects that cytonuclear interactions have on fitness-related traits in Arabidopsis thaliana. To do so, we created a unique series of 56 cytolines resulting from cytoplasmic substitutions among eight natural accessions reflecting within-species genetic diversity. An assessment of these cytolines and their parental lines scored for 28 adaptive whole-organism phenotypes showed that a large proportion of phenotypic traits (23 of 28) were affected by cytonuclear interactions. The effects of these interactions varied from slight but frequent across cytolines to strong in some specific parental pairs. Two parental pairs accounted for half of the significant pairwise interactions. In one parental pair, Ct-1/Sha, we observed symmetrical phenotypic responses between the two nuclear backgrounds when combined with specific cytoplasms, suggesting nuclear differentiation at loci involved in cytonuclear epistasis. In contrast, asymmetrical phenotypic responses were observed in another parental pair, Cvi-0/Sha. In the Cvi-0 nuclear background, fecundity and phenology-related traits were strongly affected by the Sha cytoplasm, leading to a modified reproductive strategy without penalizing total seed production. These results indicate that natural variation in cytoplasmic and nuclear genomes interact to shape integrative traits that contribute to adaptation, thereby suggesting that cytonuclear interactions can play a major role in the evolutionary dynamics of A. thaliana. PMID:26979961

  16. Disrupted trophic interactions affect recruitment of boreal deciduous and coniferous trees in northern Europe.

    PubMed

    Angelstam, Per; Manton, Michael; Pedersen, Simen; Elbakidze, Marine

    2017-01-23

    Loss of large carnivore populations may lead to increased population densities of large herbivores, and subsequent cascading effects on the composition, structure, and function of ecosystems. Using a macroecological approach based on studies in multiple boreal forest landscapes in the Baltic Sea region and Russia, we tested the hypothesis that disrupted trophic interactions among large carnivores and large herbivores affect the recruitment of both ecologically and economically valuable tree species. We measured damage levels on young trees and large herbivore density in 10 local landscapes representing a gradient from extinct to extant populations of both large carnivores and large herbivores. We also tested the alternative hypothesis that forest management intensity is correlated to reduced recruitment of these tree species. At the macroecological scale there was an inverse relationship between the number of large carnivores and large herbivores. This coincided with a steep gradient in browsing damage on the ecologically important aspen, rowan and sallow as hosts for specialized species, as well as the economically important Scots pine. In one landscape hunting had replaced the presence of carnivores. Mean damage levels of these four tree species were correlated with large herbivore abundance, but not with forest management intensity. We discuss the pros and cons of this macroecological approach, as well as the challenge of governing and managing trophic interactions at multiple scales.

  17. Effects of geographical heterogeneity in species interactions on the evolution of venom genes

    PubMed Central

    Chang, Dan; Olenzek, Amy M.; Duda, Thomas F.

    2015-01-01

    Geographical heterogeneity in the composition of biotic interactions can create a mosaic of selection regimes that may drive the differentiation of phenotypes that operate at the interface of these interactions. Nonetheless, little is known about effects of these geographical mosaics on the evolution of genes encoding traits associated with species interactions. Predatory marine snails of the family Conidae use venom, a cocktail of conotoxins, to capture prey. We characterized patterns of geographical variation at five conotoxin genes of a vermivorous species, Conus ebraeus, at Hawaii, Guam and American Samoa, and evaluated how these patterns of variation are associated with geographical heterogeneity in prey utilization. All populations show distinct patterns of prey utilization. Three ‘highly polymorphic’ conotoxin genes showed significant geographical differences in allelic frequency, and appear to be affected by different modes of selection among populations. Two genes exhibited low levels of diversity and a general lack of differentiation among populations. Levels of diversity of ‘highly polymorphic’ genes exhibit a positive relationship with dietary breadth. The different patterns of evolution exhibited by conotoxin genes suggest that these genes play different roles in prey capture, and that some genes are more greatly affected by differences in predator–prey interactions than others. Moreover, differences in dietary breadth appear to have a greater influence on the differentiation of venoms than differences in the species of prey. PMID:25788600

  18. Metabolomics Reveals Cryptic Interactive Effects of Species Interactions and Environmental Stress on Nitrogen and Sulfur Metabolism in Seagrass.

    PubMed

    Hasler-Sheetal, Harald; Castorani, Max C N; Glud, Ronnie N; Canfield, Donald E; Holmer, Marianne

    2016-11-01

    Eutrophication of estuaries and coastal seas is accelerating, increasing light stress on subtidal marine plants and changing their interactions with other species. To date, we have limited understanding of how such variations in environmental and biological stress modify the impact of interactions among foundational species and eventually affect ecosystem health. Here, we used metabolomics to assess the impact of light reductions on interactions between the seagrass Zostera marina, an important habitat-forming marine plant, and the abundant and commercially important blue mussel Mytilus edulis. Plant performance varied with light availability but was unaffected by the presence of mussels. Metabolomic analysis, on the other hand, revealed an interaction between light availability and presence of M. edulis on seagrass metabolism. Under high light, mussels stimulated seagrass nitrogen and energy metabolism. Conversely, in low light mussels impeded nitrogen and energy metabolism, and enhanced responses against sulfide toxicity, causing inhibited oxidative energy metabolism and tissue degradation. Metabolomic analysis thereby revealed cryptic changes to seagrass condition that could not be detected by traditional approaches. Our findings suggest that coastal eutrophication and associated reductions in light may shift seagrass-bivalve interactions from mutualistic to antagonistic, which is important for conservation management of seagrass meadows.

  19. Cross-Species Affective Neuroscience Decoding of the Primal Affective Experiences of Humans and Related Animals

    PubMed Central

    Panksepp, Jaak

    2011-01-01

    Background The issue of whether other animals have internally felt experiences has vexed animal behavioral science since its inception. Although most investigators remain agnostic on such contentious issues, there is now abundant experimental evidence indicating that all mammals have negatively and positively-valenced emotional networks concentrated in homologous brain regions that mediate affective experiences when animals are emotionally aroused. That is what the neuroscientific evidence indicates. Principal Findings The relevant lines of evidence are as follows: 1) It is easy to elicit powerful unconditioned emotional responses using localized electrical stimulation of the brain (ESB); these effects are concentrated in ancient subcortical brain regions. Seven types of emotional arousals have been described; using a special capitalized nomenclature for such primary process emotional systems, they are SEEKING, RAGE, FEAR, LUST, CARE, PANIC/GRIEF and PLAY. 2) These brain circuits are situated in homologous subcortical brain regions in all vertebrates tested. Thus, if one activates FEAR arousal circuits in rats, cats or primates, all exhibit similar fear responses. 3) All primary-process emotional-instinctual urges, even ones as complex as social PLAY, remain intact after radical neo-decortication early in life; thus, the neocortex is not essential for the generation of primary-process emotionality. 4) Using diverse measures, one can demonstrate that animals like and dislike ESB of brain regions that evoke unconditioned instinctual emotional behaviors: Such ESBs can serve as ‘rewards’ and ‘punishments’ in diverse approach and escape/avoidance learning tasks. 5) Comparable ESB of human brains yield comparable affective experiences. Thus, robust evidence indicates that raw primary-process (i.e., instinctual, unconditioned) emotional behaviors and feelings emanate from homologous brain functions in all mammals (see Appendix S1), which are regulated by higher

  20. Origin matters: diversity affects the performance of alien invasive species but not of native species.

    PubMed

    Sun, Yan; Müller-Schärer, Heinz; Maron, John L; Schaffner, Urs

    2015-06-01

    At local scales, it has often been found that invasibility decreases with increasing resident plant diversity. However, whether resident community diversity similarly resists invasion by alien versus native species is seldom studied. We examined this issue by invading constructed native plant assemblages that varied in species and functional richness with invasive alien or native Asteraceae species. Assemblages were also invaded with spotted knapweed, Centaurea stoebe, a native European aster that has been previously used in diversity-invasibility experiments in North America. We also conducted a field survey to explore the generality of the patterns generated from our experimental study. Both experimental and observational work revealed that increasing diversity reduced the performance of alien but not native invaders. Centaurea stoebe invading its native community performed poorly regardless of resident diversity, whereas in a parallel, previously published study conducted in North America, C. stoebe easily invaded low-diversity but not high-diversity assemblages. Our results suggest that diversity is an attribute of resident communities that makes them more or less susceptible to invasion by novel invasive alien but not native plant species.

  1. Macrofauna assemblage composition and soil moisture interact to affect soil ecosystem functions

    NASA Astrophysics Data System (ADS)

    Collison, E. J.; Riutta, T.; Slade, E. M.

    2013-02-01

    Changing climatic conditions and habitat fragmentation are predicted to alter the soil moisture conditions of temperate forests. It is not well understood how the soil macrofauna community will respond to changes in soil moisture, and how changes to species diversity and community composition may affect ecosystem functions, such as litter decomposition and soil fluxes. Moreover, few studies have considered the interactions between the abiotic and biotic factors that regulate soil processes. Here we attempt to disentangle the interactive effects of two of the main factors that regulate soil processes at small scales - moisture and macrofauna assemblage composition. The response of assemblages of three common temperate soil invertebrates (Glomeris marginata Villers, Porcellio scaber Latreille and Philoscia muscorum Scopoli) to two contrasting soil moisture levels was examined in a series of laboratory mesocosm experiments. The contribution of the invertebrates to the leaf litter mass loss of two common temperate tree species of contrasting litter quality (easily decomposing Fraxinus excelsior L. and recalcitrant Quercus robur L.) and to soil CO2 fluxes were measured. Both moisture conditions and litter type influenced the functioning of the invertebrate assemblages, which was greater in high moisture conditions compared with low moisture conditions and on good quality vs. recalcitrant litter. In high moisture conditions, all macrofauna assemblages functioned at equal rates, whereas in low moisture conditions there were pronounced differences in litter mass loss among the assemblages. This indicates that species identity and assemblage composition are more important when moisture is limited. We suggest that complementarity between macrofauna species may mitigate the reduced functioning of some species, highlighting the importance of maintaining macrofauna species richness.

  2. Interactions of neurons with topographic nano cues affect branching morphology mimicking neuron-neuron interactions.

    PubMed

    Baranes, Koby; Kollmar, Davida; Chejanovsky, Nathan; Sharoni, Amos; Shefi, Orit

    2012-08-01

    We study the effect of topographic nano-cues on neuronal growth-morphology using invertebrate neurons in culture. We use photolithography to fabricate substrates with repeatable line-pattern ridges of nano-scale heights of 10-150 nm. We plate leech neurons atop the patterned-substrates and compare their growth pattern to neurons plated atop non-patterned substrates. The model system allows us the analysis of single neurite-single ridge interactions. The use of high resolution electron microscopy reveals small filopodia processes that attach to the line-pattern ridges. These fine processes, that cannot be detected in light microscopy, add anchoring sites onto the side of the ridges, thus additional physical support. These interactions of the neuronal process dominantly affect the neuronal growth direction. We analyze the response of the entire neuronal branching tree to the patterned substrates and find significant effect on the growth patterns compared to non-patterned substrates. Moreover, interactions with the nano-cues trigger a growth strategy similarly to interactions with other neuronal cells, as reflected in their morphometric parameters. The number of branches and the number of neurites originating from the soma decrease following the interaction demonstrating a tendency to a more simplified neuronal branching tree. The effect of the nano-cues on the neuronal function deserves further investigation and will strengthen our understanding of the interplay between function and form.

  3. [Coccus species affecting Coffea arabica in Brazil (Coccoideae: Coccidae) and the redescription of two species].

    PubMed

    de Willink, Maria C Granara; Pirovani, Victor D; Ferreira, Paulo S F

    2010-01-01

    Five Coccus on Coffea arabica from the states of Bahia, Espírito Santo and Minas Gerais were studied. Females were prepared and mounted in Canada balsam. Coccus brasiliensis Fonseca and Coccus lizeri (Fonseca) were redescribed and Coccus alpinus De Lotto, Coccus celatus De Lotto and Coccus viridis (Green) were characterized. A key to species and illustration of all of them are included. Coccus alpinus and C. celatus are new records for Brazil and the Neotropical Region.

  4. Reactive oxygen species, essential molecules, during plant-pathogen interactions.

    PubMed

    Camejo, Daymi; Guzmán-Cedeño, Ángel; Moreno, Alexander

    2016-06-01

    Reactive oxygen species (ROS) are continually generated as a consequence of the normal metabolism in aerobic organisms. Accumulation and release of ROS into cell take place in response to a wide variety of adverse environmental conditions including salt, temperature, cold stresses and pathogen attack, among others. In plants, peroxidases class III, NADPH oxidase (NOX) locates in cell wall and plasma membrane, respectively, may be mainly enzymatic systems involving ROS generation. It is well documented that ROS play a dual role into cells, acting as important signal transduction molecules and as toxic molecules with strong oxidant power, however some aspects related to its function during plant-pathogen interactions remain unclear. This review focuses on the principal enzymatic systems involving ROS generation addressing the role of ROS as signal molecules during plant-pathogen interactions. We described how the chloroplasts, mitochondria and peroxisomes perceive the external stimuli as pathogen invasion, and trigger resistance response using ROS as signal molecule.

  5. Mosquito species succession and physicochemical factors affecting their abundance in rice fields in Mwea, Kenya.

    PubMed

    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Muriu, Simon; Jacob, Benjamin; Kabiru, Ephantus; Gu, Weidong; Mbogo, Charles; Githure, John; Novak, Robert

    2007-03-01

    The succession of mosquito species and abiotic factors affecting their distribution and abundance in rice (Oryza spp.) fields was investigated over a 16-wk rice growing cycle covering the period between January and May 2006. Fifteen experimental rice plots were sampled for mosquito larvae and characterized based on rice height, number of tillers, floating vegetation cover, water depth, water temperature, turbidity, salinity, pH, dissolved oxygen, total dissolved solids, and conductivity. Microscopic identification of 3,025 larvae yielded nine mosquito species predominated by Anopheles arabiensis Patton (45.0%), Culex quinquefasciatus Say (35.8%), Anopheles pharoensis Theobald (9.0%) and Ficalbia splendens Theobald (7.1%). Other species, including Anopheles rufipes Gough, Anopheles coustani Laveran, Anonopheles maculipalpis Giles, Culex annulioris Theobald, and Culex poicilipes Theobald made up 3.1% of the total collection. Anopheles gambiae s.l., Cx. quinquefasciatus, and An. pharoensis occurred throughout the cycle, but they were more abundant up to 4 wk posttransplanting with peaks after fertilizer application. As rice plants became established, three groups of mosquitoes were recognized: the first groups included An. rufipes, Fl. splendens, and Cx. annulioris, which occurred throughout much of the second half of the rice cycle, whereas the second group included Cx. poicilipes, which was found in the middle of the rice cycle. An. coustani and An. maculipalpis formed the third group occurring toward the end of the cycle. Dissolved oxygen, number of tillers, and rice height were negatively associated with the abundance ofAn. arabiensis and Cx. quinquefasciatus larvae. In addition, Cx. quinquefasciatus also was associated with water depth (-ve) and turbidity (+ve). Abundance of An. pharoensis larvae was significantly associated with water temperature (+ve), the number of tillers (-ve), and rice height (-ve), whereas Fl. splendens was significantly associated with

  6. Determining the factors affecting the distribution of Muscari latifolium, an endemic plant of Turkey, and a mapping species distribution model.

    PubMed

    Yilmaz, Hatice; Yilmaz, Osman Yalçın; Akyüz, Yaşar Feyza

    2017-02-01

    Species distribution modeling was used to determine factors among the large predictor candidate data set that affect the distribution of Muscari latifolium, an endemic bulbous plant species of Turkey, to quantify the relative importance of each factor and make a potential spatial distribution map of M. latifolium. Models were built using the Boosted Regression Trees method based on 35 presence and 70 absence records obtained through field sampling in the Gönen Dam watershed area of the Kazdağı Mountains in West Anatolia. Large candidate variables of monthly and seasonal climate, fine-scale land surface, and geologic and biotic variables were simplified using a BRT simplifying procedure. Analyses performed on these resources, direct and indirect variables showed that there were 14 main factors that influence the species' distribution. Five of the 14 most important variables influencing the distribution of the species are bedrock type, Quercus cerris density, precipitation during the wettest month, Pinus nigra density, and northness. These variables account for approximately 60% of the relative importance for determining the distribution of the species. Prediction performance was assessed by 10 random subsample data sets and gave a maximum the area under a receiver operating characteristic curve (AUC) value of 0.93 and an average AUC value of 0.8. This study provides a significant contribution to the knowledge of the habitat requirements and ecological characteristics of this species. The distribution of this species is explained by a combination of biotic and abiotic factors. Hence, using biotic interaction and fine-scale land surface variables in species distribution models improved the accuracy and precision of the model. The knowledge of the relationships between distribution patterns and environmental factors and biotic interaction of M. latifolium can help develop a management and conservation strategy for this species.

  7. Tree species and functional traits but not species richness affect interrill erosion processes in young subtropical forests

    NASA Astrophysics Data System (ADS)

    Seitz, S.; Goebes, P.; Song, Z.; Bruelheide, H.; Härdtle, W.; Kühn, P.; Li, Y.; Scholten, T.

    2016-01-01

    Soil erosion is seriously threatening ecosystem functioning in many parts of the world. In this context, it is assumed that tree species richness and functional diversity of tree communities can play a critical role in improving ecosystem services such as erosion control. An experiment with 170 micro-scale run-off plots was conducted to investigate the influence of tree species and tree species richness as well as functional traits on interrill erosion in a young forest ecosystem. An interrill erosion rate of 47.5 Mg ha-1 a-1 was calculated. This study provided evidence that different tree species affect interrill erosion differently, while tree species richness did not affect interrill erosion in young forest stands. Thus, different tree morphologies have to be considered, when assessing soil erosion under forest. High crown cover and leaf area index reduced interrill erosion in initial forest ecosystems, whereas rising tree height increased it. Even if a leaf litter cover was not present, the remaining soil surface cover by stones and biological soil crusts was the most important driver for soil erosion control. Furthermore, soil organic matter had a decreasing influence on interrill erosion. Long-term monitoring of soil erosion under closing tree canopies is necessary, and a wide range of functional tree traits should be considered in future research.

  8. Calcite and Picocyanobacteria in Lakes: Factors Affecting Their Interaction

    NASA Astrophysics Data System (ADS)

    Dittrich, M.; Obst, M.; Mavrocordatos, D.

    2003-12-01

    Calcites build large deposits which have been observed in the rock record throughout geological time at various localities around the globe. Carbonate deposits have affected atmospheric carbon dioxide concentration. As it has been generally accepted, inorganic precipitation represents a source of carbon dioxide on short geological time scales and a sink of inorganic carbon at long time scales from millions to thousands of millions years. However, recent research indicates that calcite deposits may result from microbial calcification instead of inorganic precipitation. In this case the process may reduce atmospheric carbon dioxide on geologically short time scales. Thus the effect of carbonate sediment deposition on global carbon cycling depends on the origin of carbonate. Thus it is essential to understand the cause and the key parameters affecting calcite precipitation. The role of algae and bacteria in calcite formation in lakes has not been evaluated in detail. Some evidence, however, exists supporting precipitation of calcium carbonate by microbes as the origin of whiting. Several field studies on lakes have also produced puzzling results: The peaks of algal blooms were often not found at the same time as precipitation events of calcite. We suspect that parts of the discrepancies in the interpretation of field observations are due to the activity of autotrophic picoplankton. The unicellular autotrophic picoplankton (APP) is a ubiquitous component of pelagic ecosystems. But it has often been overlooked due to its small cell size of 0.2 - 2 μ m in diameter. Coccoid picocyanobacteria of the Synechococcus-type dominate the picoplankton community in most oligotrophic systems. Recently, laboratory experiments and field observations suggested that APP may play an important role in calcite precipitation. The aim of this study was to examine the influence of environmental factors such as saturation state, concentration of different dissolved ions and characteristics of

  9. Two-species-coagulation approach to consensus by group level interactions

    NASA Astrophysics Data System (ADS)

    Escudero, Carlos; Macià, Fabricio; Velázquez, Juan J. L.

    2010-07-01

    We explore the self-organization dynamics of a set of entities by considering the interactions that affect the different subgroups conforming the whole. To this end, we employ the widespread example of coagulation kinetics, and characterize which interaction types lead to consensus formation and which do not, as well as the corresponding different macroscopic patterns. The crucial technical point is extending the usual one species coagulation dynamics to the two species one. This is achieved by means of introducing explicitly solvable kernels which have a clear physical meaning. The corresponding solutions are calculated in the long time limit, in which consensus may or may not be reached. The lack of consensus is characterized by means of scaling limits of the solutions. The possible applications of our results to some topics in which consensus reaching is fundamental, such as collective animal motion and opinion spreading dynamics, are also outlined.

  10. The role of biotic interactions in shaping distributions and realised assemblages of species: implications for species distribution modelling

    PubMed Central

    Wisz, Mary Susanne; Pottier, Julien; Kissling, W Daniel; Pellissier, Loïc; Lenoir, Jonathan; Damgaard, Christian F; Dormann, Carsten F; Forchhammer, Mads C; Grytnes, John-Arvid; Guisan, Antoine; Heikkinen, Risto K; Høye, Toke T; Kühn, Ingolf; Luoto, Miska; Maiorano, Luigi; Nilsson, Marie-Charlotte; Normand, Signe; Öckinger, Erik; Schmidt, Niels M; Termansen, Mette; Timmermann, Allan; Wardle, David A; Aastrup, Peter; Svenning, Jens-Christian

    2013-01-01

    Predicting which species will occur together in the future, and where, remains one of the greatest challenges in ecology, and requires a sound understanding of how the abiotic and biotic environments interact with dispersal processes and history across scales. Biotic interactions and their dynamics influence species' relationships to climate, and this also has important implications for predicting future distributions of species. It is already well accepted that biotic interactions shape species' spatial distributions at local spatial extents, but the role of these interactions beyond local extents (e.g. 10 km2 to global extents) are usually dismissed as unimportant. In this review we consolidate evidence for how biotic interactions shape species distributions beyond local extents and review methods for integrating biotic interactions into species distribution modelling tools. Drawing upon evidence from contemporary and palaeoecological studies of individual species ranges, functional groups, and species richness patterns, we show that biotic interactions have clearly left their mark on species distributions and realised assemblages of species across all spatial extents. We demonstrate this with examples from within and across trophic groups. A range of species distribution modelling tools is available to quantify species environmental relationships and predict species occurrence, such as: (i) integrating pairwise dependencies, (ii) using integrative predictors, and (iii) hybridising species distribution models (SDMs) with dynamic models. These methods have typically only been applied to interacting pairs of species at a single time, require a priori ecological knowledge about which species interact, and due to data paucity must assume that biotic interactions are constant in space and time. To better inform the future development of these models across spatial scales, we call for accelerated collection of spatially and temporally explicit species data. Ideally

  11. The Promise of Interactive Video: An Affective Search.

    ERIC Educational Resources Information Center

    Hon, David

    1983-01-01

    Argues that factors that create a feeling of interactivity in the human situation--response time, spontaneity, lack of distractors--should be included as prime elements in the design of human/machine systems, e.g., computer assisted instruction and interactive video. A computer/videodisc learning system for cardio-pulmonary resuscitation and its…

  12. Mechanism of interaction of Salmonella and Schistosoma species.

    PubMed Central

    Melhem, R F; LoVerde, P T

    1984-01-01

    In endemic areas where Salmonella and Schistosoma species co-occur, several lines of evidence suggest a synergistic bacteria-parasite interaction that results in a protracted course for the salmonella infection that has proven difficult to diagnose and therapeutically remedy. In an in vitro system using a pilus-negative and a pilus-producing transductant strain of Salmonella typhimurium we show that pili are the ligands for bacterial adherence to the schistosome surface tegument. Antipili antibodies produced in rabbits against purified pili, purified and digested to monovalent (Fab) fragments, blocked the association of Salmonella sp. to the surface tegument of Schistosoma sp., further demonstrating that pili are the appendages necessary for bacteria-parasite surface interaction. The use of carbohydrates, lectins, and enzymes demonstrated that the bacteria-parasite surface interaction was specific, mediated by pili that specifically recognize and bind to mannose-like receptors, probably glycolipids, on the surface of the worms. We suggest that prolonged salmonellosis in schistosome-infected patients is due to an association of Salmonella sp. with the schistosome worms themselves and further that the schistosome worms provide a multiplication focus for these bacteria in the portal mesenteric system, with a persisting bacteremia following. PMID:6143728

  13. Species interactions and the effects of climate variability on a wetland amphibian metacommunity.

    PubMed

    Davis, Courtney L; Miller, David A W; Walls, Susan C; Barichivich, William J; Riley, Jeffrey W; Brown, Mary E

    2017-01-01

    Disentangling the role that multiple interacting factors have on species responses to shifting climate poses a significant challenge. However, our ability to do so is of utmost importance to predict the effects of climate change on species distributions. We examined how populations of three species of wetland-breeding amphibians, which varied in life history requirements, responded to a six-year period of extremely variable precipitation. This interval was punctuated by both extensive drought and heavy precipitation and flooding, providing a natural experiment to measure community responses to environmental perturbations. We estimated occurrence dynamics using a discrete hidden Markov modeling approach that incorporated information regarding habitat state and predator-prey interactions. This approach allowed us to measure how metapopulation dynamics of each amphibian species was affected by interactions among weather, wetland hydroperiod, and co-occurrence with fish predators. The pig frog, a generalist, proved most resistant to perturbations, with both colonization and persistence being unaffected by seasonal variation in precipitation or co-occurrence with fishes. The ornate chorus frog, an ephemeral wetland specialist, responded positively to periods of drought owing to increased persistence and colonization rates during periods of low-rainfall. Low probabilities of occurrence of the ornate chorus frog in long-duration wetlands were driven by interactions with predators due to low colonization rates when fishes were present. The mole salamander was most sensitive to shifts in water availability. In our study area, this species never occurred in short-duration wetlands and persistence probabilities decreased during periods of drought. At the same time, negative effects occurred with extreme precipitation because flooding facilitated colonization of fishes to isolated wetlands and mole salamanders did not colonize wetlands once fishes were present. We demonstrate

  14. Species interactions and the effects of climate variability on a wetland amphibian metacommunity

    USGS Publications Warehouse

    Davis, Courtney L.; Miller, David A.W.; Walls, Susan C.; Barichivich, William J.; Riley, Jeffrey W.; Brown, Mary E.

    2017-01-01

    Disentangling the role that multiple interacting factors have on species responses to shifting climate poses a significant challenge. However, our ability to do so is of utmost importance to predict the effects of climate change on species distributions. We examined how populations of three species of wetland-breeding amphibians, which varied in life history requirements, responded to a six-year period of extremely variable precipitation. This interval was punctuated by both extensive drought and heavy precipitation and flooding, providing a natural experiment to measure community responses to environmental perturbations. We estimated occurrence dynamics using a discrete hidden Markov modeling approach that incorporated information regarding habitat state and predator–prey interactions. This approach allowed us to measure how metapopulation dynamics of each amphibian species was affected by interactions among weather, wetland hydroperiod, and co-occurrence with fish predators. The pig frog, a generalist, proved most resistant to perturbations, with both colonization and persistence being unaffected by seasonal variation in precipitation or co-occurrence with fishes. The ornate chorus frog, an ephemeral wetland specialist, responded positively to periods of drought owing to increased persistence and colonization rates during periods of low-rainfall. Low probabilities of occurrence of the ornate chorus frog in long-duration wetlands were driven by interactions with predators due to low colonization rates when fishes were present. The mole salamander was most sensitive to shifts in water availability. In our study area, this species never occurred in short-duration wetlands and persistence probabilities decreased during periods of drought. At the same time, negative effects occurred with extreme precipitation because flooding facilitated colonization of fishes to isolated wetlands and mole salamanders did not colonize wetlands once fishes were present. We

  15. Microsatellite size homoplasies and null alleles do not affect species diagnosis and population genetic analysis in a fungal species complex.

    PubMed

    Queloz, V; Duò, A; Sieber, T N; Grünig, C R

    2010-03-01

    The suitability of 13 microsatellite loci for species diagnosis and population genetics in 11 species of the Phialocephala fortinii s.l.-Acephala applanata species complex (PAC) was assessed. Two data sets were compared to test possible biases in species typing and clone detection resulting from null alleles and size homoplasies. The first data set was based on fragment lengths derived from a multiplex polymerase chain reaction (PCR) assay and the second data set was received from singleplex PCR at lower stringency and sequencing. Most null alleles observed in the multiplex PCR assay could be amplified during singleplex PCR under less stringent conditions. Size homoplasies resulting from mutations in flanking regions and differences in microsatellite structures were observed. For example, Phialocephala uotolensis possessed a (CT)(13) in addition to the (GT)(x) motif at locus mPF_0644. Despite the occurrence of null alleles and size homoplasies, species diagnosis and population genetic analysis studies were not affected. These markers will facilitate studies on population biology, ecology and biogeography of PAC species.

  16. Temperature dependence of trophic interactions are driven by asymmetry of species responses and foraging strategy.

    PubMed

    Dell, Anthony I; Pawar, Samraat; Savage, Van M

    2014-01-01

    Environmental temperature has systematic effects on rates of species interactions, primarily through its influence on organismal physiology. We present a mechanistic model for the thermal response of consumer-resource interactions. We focus on how temperature affects species interactions via key traits - body velocity, detection distance, search rate and handling time - that underlie per capita consumption rate. The model is general because it applies to all foraging strategies: active-capture (both consumer and resource body velocity are important), sit-and-wait (resource velocity dominates) and grazing (consumer velocity dominates). The model predicts that temperature influences consumer-resource interactions primarily through its effects on body velocity (either of the consumer, resource or both), which determines how often consumers and resources encounter each other, and that asymmetries in the thermal responses of interacting species can introduce qualitative, not just quantitative, changes in consumer-resource dynamics. We illustrate this by showing how asymmetries in thermal responses determine equilibrium population densities in interacting consumer-resource pairs. We test for the existence of asymmetries in consumer-resource thermal responses by analysing an extensive database on thermal response curves of ecological traits for 309 species spanning 15 orders of magnitude in body size from terrestrial, marine and freshwater habitats. We find that asymmetries in consumer-resource thermal responses are likely to be a common occurrence. Overall, our study reveals the importance of asymmetric thermal responses in consumer-resource dynamics. In particular, we identify three general types of asymmetries: (i) different levels of performance of the response, (ii) different rates of response (e.g. activation energies) and (iii) different peak or optimal temperatures. Such asymmetries should occur more frequently as the climate changes and species' geographical

  17. Yakima River Species Interactions Studies Annual Report FY 1992.

    SciTech Connect

    Pearsons, Todd N.

    1993-08-01

    The Yakima Species Interactions Study (YSIS) was begun in September of 1989 to investigate species interactions among fish in response to proposed supplementation of salmon and steelhead in the Yakima Basin. Supplementation is defined as ''the use of artificial propagation in the attempt to maintain or increase natural production while maintaining the long term fitness of the target population, and keeping the ecological and genetic impacts on non-target populations within specified biological limits'' (BPA summary report series, 1992). Target populations are the populations of fish that will be supplemented and non-target populations are all other populations of fish. One of the goals of the proposed Yakima Fisheries Project (YFP) is to test the strategy of supplementation in the Yakima Basin. In a review of published literature and unpublished projects about supplementation, Miller et al. (1990) concluded ''Adverse impacts to wild stocks have been shown or postulated for about every type of hatchery fish introduction where the intent was to rebuild runs''. In Steward and Bjornn's (1990) review of the published literature, they stated that ''Genetic and ecological effects, and changes in productivity of the native stocks that can result from supplementation remain largely unmeasured''. Uncertainties about the effects supplementation in the upper Yakima basin may have on wild fish was the impetus for the initiation of the present studies. The YSIS has three main goals which are to: evaluate risks of ecological interactions to target and non-target populations (resolve critical uncertainties), contribute to the development of an interactions monitoring plan, and provide information that may be used to increase the probability that natural production of anadromous salmonids may be successfully increased. Information obtained will be used as the YFP planning process proceeds (adaptive management). A monitoring plan is being developed which will incorporate data

  18. A broadleaf species enhances an autotoxic conifers growth through belowground chemical interactions.

    PubMed

    Xia, Zhi-Chao; Kong, Chui-Hua; Chen, Long-Chi; Wang, Peng; Wang, Si-Long

    2016-09-01

    Plants may affect the performance of neighboring plants either positively or negatively through interspecific and intraspecific interactions. Productivity of mixed-species systems is ultimately the net result of positive and negative interactions among the component species. Despite increasing knowledge of positive interactions occurring in mixed-species tree systems, relatively little is known about the mechanisms underlying such interactions. Based on data from 25-year-old experimental stands in situ and a series of controlled experiments, we test the hypothesis that a broadleaf, non-N fixing species, Michelia macclurei, facilitates the performance of an autotoxic conifer Chinese fir (Cunninghamia lanceolata) through belowground chemical interactions. Chinese fir roots released the allelochemical cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-[1,4]-diazocane- 2,5-diketone) into the soil environment, resulting in self-growth inhibition, and deterioration of soil microorganisms that improve P availability. However, when grown with M. macclurei the growth of Chinese fir was consistently enhanced. In particular, Chinese fir enhanced root growth and distribution in deep soil layers. When compared with monocultures of Chinese fir, the presence of M. macclurei reduced release and increased degradation of cyclic dipeptide in the soil, resulting in a shift from self-inhibition to chemical facilitation. This association also improved the soil microbial community by increasing arbuscular mycorrhizal fungi, and induced the production of Chinese fir roots. We conclude that interspecific interactions are less negative than intraspecific ones between non-N fixing broadleaf and autotoxic conifer species. The impacts are generated by reducing allelochemical levels, enhancing belowground mutualisms, improving soil properties, and changing root distributions as well as the net effects of all the processes within the soil. In particular, allelochemical context alters the

  19. Exposure to Cerium Dioxide Nanoparticles Differently Affect Swimming Performance and Survival in Two Daphnid Species

    PubMed Central

    Artells, Ester; Issartel, Julien; Auffan, Mélanie; Borschneck, Daniel; Thill, Antoine; Tella, Marie; Brousset, Lenka; Rose, Jérôme; Bottero, Jean-Yves; Thiéry, Alain

    2013-01-01

    The CeO2 NPs are increasingly used in industry but the environmental release of these NPs and their subsequent behavior and biological effects are currently unclear. This study evaluates for the first time the effects of CeO2 NPs on the survival and the swimming performance of two cladoceran species, Daphnia similis and Daphnia pulex after 1, 10 and 100 mg.L−1 CeO2 exposures for 48 h. Acute toxicity bioassays were performed to determine EC50 of exposed daphnids. Video-recorded swimming behavior of both daphnids was used to measure swimming speeds after various exposures to aggregated CeO2 NPs. The acute ecotoxicity showed that D. similis is 350 times more sensitive to CeO2 NPs than D. pulex, showing 48-h EC50 of 0.26 mg.L−1 and 91.79 mg.L−1, respectively. Both species interacted with CeO2 NPs (adsorption), but much more strongly in the case of D. similis. Swimming velocities (SV) were differently and significantly affected by CeO2 NPs for both species. A 48-h exposure to 1 mg.L−1 induced a decrease of 30% and 40% of the SV in D. pulex and D. similis, respectively. However at higher concentrations, the SV of D. similis was more impacted (60% off for 10 mg.L−1 and 100 mg.L−1) than the one of D. pulex. These interspecific toxic effects of CeO2 NPs are explained by morphological variations such as the presence of reliefs on the cuticle and a longer distal spine in D. similis acting as traps for the CeO2 aggregates. In addition, D. similis has a mean SV double that of D. pulex and thus initially collides with twice more NPs aggregates. The ecotoxicological consequences on the behavior and physiology of a CeO2 NPs exposure in daphnids are discussed. PMID:23977004

  20. Loss of Rare Fish Species from Tropical Floodplain Food Webs Affects Community Structure and Ecosystem Multifunctionality in a Mesocosm Experiment

    PubMed Central

    Pendleton, Richard M.; Hoeinghaus, David J.; Gomes, Luiz C.; Agostinho, Angelo A.

    2014-01-01

    Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across multiple trophic

  1. Loss of rare fish species from tropical floodplain food webs affects community structure and ecosystem multifunctionality in a mesocosm experiment.

    PubMed

    Pendleton, Richard M; Hoeinghaus, David J; Gomes, Luiz C; Agostinho, Angelo A

    2014-01-01

    Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across multiple trophic

  2. Prey dispersal rate affects prey species composition and trait diversity in response to multiple predators in metacommunities.

    PubMed

    Howeth, Jennifer G; Leibold, Mathew A

    2010-09-01

    1. Recent studies indicate that large-scale spatial processes can alter local community structuring mechanisms to determine local and regional assemblages of predators and their prey. In metacommunities, this may occur when the functional diversity represented in the regional predator species pool interacts with the rate of prey dispersal among local communities to affect prey species diversity and trait composition at multiple scales. 2. Here, we test for effects of prey dispersal rate and spatially and temporally heterogeneous predation from functionally dissimilar predators on prey structure in pond mesocosm metacommunities. An experimental metacommunity consisted of three pond mesocosm communities supporting two differentially size-selective invertebrate predators and their zooplankton prey. In each metacommunity, two communities maintained constant predation and supported either Gyrinus sp. (Coleoptera) or Notonecta ungulata (Hemiptera) predators generating a spatial prey refuge while the third community supported alternating predation from Gyrinus sp. and N. ungulata generating a temporal prey refuge. Mesocosm metacommunities were connected at either low (0.7% day(-1)) or high (10% day(-1)) planktonic prey dispersal. The diversity, composition and body size of zooplankton prey were measured at local and regional (metacommunity) scales. 3. Metacommunities experiencing the low prey dispersal rate supported the greatest regional prey species diversity (H') and evenness (J'). Neither dispersal rate nor predation regime affected local prey diversity or evenness. The spatial prey refuge at low dispersal maintained the largest difference in species composition and body size diversity between communities under Gyrinus and Notonecta predation, suggesting that species sorting was operating at the low dispersal rate. There was no effect of dispersal rate on species diversity or body size distribution in the temporal prey refuge. 4. The frequency distribution, but not

  3. Do non-native plant species affect the shape of productivity-diversity relationships?

    USGS Publications Warehouse

    Drake, J.M.; Cleland, E.E.; Horner-Devine, M. C.; Fleishman, E.; Bowles, C.; Smith, M.D.; Carney, K.; Emery, S.; Gramling, J.; Vandermast, D.B.; Grace, J.B.

    2008-01-01

    The relationship between ecosystem processes and species richness is an active area of research and speculation. Both theoretical and experimental studies have been conducted in numerous ecosystems. One finding of these studies is that the shape of the relationship between productivity and species richness varies considerably among ecosystems and at different spatial scales, though little is known about the relative importance of physical and biological mechanisms causing this variation. Moreover, despite widespread concern about changes in species' global distributions, it remains unclear if and how such large-scale changes may affect this relationship. We present a new conceptual model of how invasive species might modulate relationships between primary production and species richness. We tested this model using long-term data on relationships between aboveground net primary production and species richness in six North American terrestrial ecosystems. We show that primary production and abundance of non-native species are both significant predictors of species richness, though we fail to detect effects of invasion extent on the shapes of the relationship between species richness and primary production.

  4. Richness and species composition of arboreal arthropods affected by nutrients and predators: a press experiment.

    PubMed

    Gruner, Daniel S; Taylor, Andrew D

    2006-04-01

    A longstanding goal for ecologists is to understand the processes that maintain biological diversity in communities, yet few studies have investigated the combined effects of predators and resources on biodiversity in natural ecosystems. We fertilized nutrient limited plots and excluded insectivorous birds in a randomized block design, and examined the impacts on arthropods associated with the dominant tree in the Hawaiian Islands, Metrosideros polymorpha (Myrtaceae). After 33 months, the species load (per foliage mass) of herbivores and carnivores increased with fertilization, but rarified richness (standardized to abundance) did not change. Fertilization depressed species richness of arboreal detritivores, and carnivore richness dropped in caged, unfertilized plots, both because of the increased dominance of common, introduced species with treatments. Herbivore species abundance distributions were more equitable than other trophic levels following treatments, and fertilization added specialized native species without changing relativized species richness. Overall, bird removal and nutrient addition treatments on arthropod richness acted largely independently, but with countervailing influences that obscured distinct top-down and bottom-up effects on different trophic levels. This study demonstrates that species composition, biological invasions, and the individuality of species traits may complicate efforts to predict the interactive effects of resources and predation on species diversity in food webs.

  5. Vagal Reactivity and Affective Adjustment in Infants during Interaction Challenges.

    ERIC Educational Resources Information Center

    Bazhenova, Olga V.; Plonskaia, Oxana; Porges, Stephen W.

    2001-01-01

    Evaluated respiratory sinus arrhythmia (RSA) and heart period in 5-month-olds during interaction challenges. Found that during object-mediated challenge, RSA increases were uniquely related to positive engagement. During person-mediated challenge, subjects showed more complex integration of autonomic and behavioral responses such that only infants…

  6. Spatial gradient in nitrogen deposition affects plant species frequency in acidic grasslands.

    PubMed

    Pannek, A; Duprè, C; Gowing, D J G; Stevens, C J; Diekmann, M

    2015-01-01

    Anthropogenic eutrophication impacts ecosystems worldwide. Here, we use a vegetation dataset from semi-natural grasslands on acidic soils sampled along a gradient in north-western Europe to examine the response of species frequency to nitrogen (N) deposition, controlling for the effects of other environmental variables. A second dataset of acidic grasslands from Germany and the Netherlands containing plots from different time periods was analysed to examine whether the results of the spatial gradient approach coincided with temporal changes in the abundance of species. Out of 44 studied species, 16 were affected by N deposition, 12 of them negatively. Soil pH and phosphorus (P) influenced 24 and 14 species, respectively, predominantly positively. Fewer species were related to the soil contents of NO3(-) or NH4(+), with no significant differences between the number of positive and negative effects. Whereas the temporal change of species was unrelated to their responses to pH, species responding negatively to N deposition, soil P and NO3(-) showed a significant decline over time in both countries. Species that were negatively affected by high N deposition and/or high soil P also showed a negative temporal trend and could be characterised by short stature and slow growth. The results confirm the negative role of N deposition for many plant species in semi-natural acidic grasslands. The negative temporal trends of species sensitive to high N deposition and soil P values clearly show a need for maintaining low soil nutrient status and for restoring the formerly infertile conditions in nutrient-enriched grasslands.

  7. Experimentally reducing species abundance indirectly affects food web structure and robustness.

    PubMed

    Barbosa, Milton; Fernandes, G Wilson; Lewis, Owen T; Morris, Rebecca J

    2017-03-01

    Studies on the robustness of ecological communities suggest that the loss or reduction in abundance of individual species can lead to secondary and cascading extinctions. However, most such studies have been simulation-based analyses of the effect of primary extinction on food web structure. In a field experiment we tested the direct and indirect effects of reducing the abundance of a common species, focusing on the diverse and self-contained assemblage of arthropods associated with an abundant Brazilian shrub, Baccharis dracunculifolia D.C. (Asteraceae). Over a 5-month period we experimentally reduced the abundance of Baccharopelma dracunculifoliae (Sternorrhyncha: Psyllidae), the commonest galling species associated with B. dracunculifolia, in 15 replicate plots paired with 15 control plots. We investigated direct effects of the manipulation on parasitoids attacking B. dracunculifoliae, as well as indirect effects (mediated via a third species or through the environment) on 10 other galler species and 50 associated parasitoid species. The experimental manipulation significantly increased parasitism on B. dracunculifoliae in the treatment plots, but did not significantly alter either the species richness or abundance of other galler species. Compared to control plots, food webs in manipulated plots had significantly lower values of weighted connectance, interaction evenness and robustness (measured as simulated tolerance to secondary extinction), even when B. dracunculifoliae was excluded from calculations. Parasitoid species were almost entirely specialized to individual galler species, so the observed effects of the manipulation on food web structure could not have propagated via the documented trophic links. Instead, they must have spread either through trophic links not included in the webs (e.g. shared predators) or non-trophically (e.g. through changes in habitat availability). Our results highlight that the inclusion of both trophic and non

  8. Node-by-node disassembly of a mutualistic interaction web driven by species introductions

    PubMed Central

    Rodriguez-Cabal, Mariano A.; Barrios-Garcia, M. Noelia; Amico, Guillermo C.; Aizen, Marcelo A.; Sanders, Nathan J.

    2013-01-01

    Interaction webs summarize the diverse interactions among species in communities. The addition or loss of particular species and the alteration of key interactions can lead to the disassembly of the entire interaction web, although the nontrophic effects of species loss on interaction webs are poorly understood. We took advantage of ongoing invasions by a suite of exotic species to examine their impact in terms of the disassembly of an interaction web in Patagonia, Argentina. We found that the reduction of one species (a host of a keystone mistletoe species) resulted in diverse indirect effects that led to the disassembly of an interaction web through the loss of the mistletoe, two key seed-dispersers (a marsupial and a bird), and a pollinator (hummingbird). Our results demonstrate that the gains and losses of species are both consequences and drivers of global change that can lead to underappreciated cascading coextinctions through the disruption of mutualisms. PMID:24067653

  9. Habitat fragmentation and species loss across three interacting trophic levels: effects of life-history and food-web traits.

    PubMed

    Cagnolo, Luciano; Valladares, Graciela; Salvo, Adriana; Cabido, Marcelo; Zak, Marcelo

    2009-10-01

    Not all species are likely to be equally affected by habitat fragmentation; thus, we evaluated the effects of size of forest remnants on trophically linked communities of plants, leaf-mining insects, and their parasitoids. We explored the possibility of differential vulnerability to habitat area reduction in relation to species-specific and food-web traits by comparing species-area regression slopes. Moreover, we searched for a synergistic effect of these traits and of trophic level. We collected mined leaves and recorded plant, leaf miner, and parasitoid species interactions in five 100-m2 transects in 19 Chaco Serrano woodland remnants in central Argentina. Species were classified into extreme categories according to body size, natural abundance, trophic breadth, and trophic level. Species-area slopes differed between groups with extreme values of natural abundance or trophic specialization. Nevertheless, synergistic effects of life-history and food-web traits were only found for trophic level and trophic breadth: area-related species loss was highest for specialist parasitoids. It has been suggested that species position within interaction webs could determine their vulnerability to extinction. Our results provide evidence that food-web parameters, such as trophic level and trophic breadth, affect species sensitivity to habitat fragmentation.

  10. Climate warming affects biological invasions by shifting interactions of plants and herbivores.

    PubMed

    Lu, Xinmin; Siemann, Evan; Shao, Xu; Wei, Hui; Ding, Jianqing

    2013-08-01

    Plants and herbivorous insects can each be dramatically affected by temperature. Climate warming may impact plant invasion success directly but also indirectly through changes in their natural enemies. To date, however, there are no tests of how climate warming shifts the interactions among invasive plants and their natural enemies to affect invasion success. Field surveys covering the full latitudinal range of invasive Alternanthera philoxeroides in China showed that a beetle introduced for biocontrol was rare or absent at higher latitudes. In contrast, plant cover and mass increased with latitude. In a 2-year field experiment near the northern limit of beetle distribution, we found the beetle sustained populations across years under elevated temperature, dramatically decreasing A. philoxeroides growth, but it failed to overwinter in ambient temperature. Together, these results suggest that warming will allow the natural enemy to expand its range, potentially benefiting biocontrol in regions that are currently too cold for the natural enemy. However, the invader may also expand its range further north in response to warming. In such cases where plants tolerate cold better than their natural enemies, the geographical gap between plant and herbivorous insect ranges may not disappear but will shift to higher latitudes, leading to a new zone of enemy release. Therefore, warming will not only affect plant invasions directly but also drive either enemy release or increase that will result in contrasting effects on invasive plants. The findings are also critical for future management of invasive species under climate change.

  11. Social interactions affecting caste development through physiological actions in termites

    PubMed Central

    Watanabe, Dai; Gotoh, Hiroki; Miura, Toru; Maekawa, Kiyoto

    2014-01-01

    A colony of social insects is not only an aggregation of individuals but also a functional unit. To achieve adaptive social behavior in fluctuating environmental conditions, in addition to coordination of physiological status in each individual, the whole colony is coordinated by interactions among colony members. The study on the regulation of social-insect colonies is termed “social physiology.” Termites, a major group of social insects, exhibit many interesting phenomena related to social physiology, such as mechanisms of caste regulation in a colony. In their colonies, there are different types of individuals, i.e., castes, which show distinctive phenotypes specialized in specific colony tasks. Termite castes comprise reproductives, soldiers and workers, and the caste composition can be altered depending on circumstances. For the regulation of caste compositions, interactions among individuals, i.e., social interactions, are thought to be important. In this article, we review previous studies on the adaptive meanings and those on the proximate mechanisms of the caste regulation in termites, and try to understand those comprehensively in terms of social physiology. Firstly, we summarize classical studies on the social interactions. Secondly, previous studies on the pheromone substances that mediate the caste regulatory mechanisms are overviewed. Then, we discuss the roles of a physiological factor, juvenile hormone (JH) in the regulation of caste differentiation. Finally, we introduce the achievements of molecular studies on the animal sociality (i.e., sociogenomics) in terms of social physiology. By comparing the proximate mechanisms of social physiology in termites with those in hymenopterans, we try to get insights into the general principles of social physiology in social animals. PMID:24782780

  12. Tree species identity and functional traits but not species richness affect interrill erosion processes in young subtropical forests

    NASA Astrophysics Data System (ADS)

    Seitz, S.; Goebes, P.; Song, Z.; Bruelheide, H.; Härdtle, W.; Kühn, P.; Li, Y.; Scholten, T.

    2015-06-01

    Soil erosion is seriously threatening ecosystem functioning in many parts of the world. In this context, it is assumed that tree species richness and functional diversity of tree communities can play a critical role in improving ecosystem services such as erosion control. An experiment with 170 micro-scale runoff plots was conducted to investigate the influence of tree species richness and identity as well as tree functional traits on interrill erosion in a young forest ecosystem. An interrill erosion rate of 47.5 t ha-1 a-1 was calculated. This study provided evidence that different tree species affect interrill erosion, but higher tree species richness did not mitigate soil losses in young forest stands. Thus, different tree morphologies have to be considered, when assessing erosion under forest. High crown cover and leaf area index reduced soil losses in initial forest ecosystems, whereas rising tree height increased them. Even if a leaf litter cover was not present, remaining soil surface cover by stones and biological soil crusts was the most important driver for soil erosion control. Furthermore, soil organic matter had a decreasing influence on soil loss. Long-term monitoring of soil erosion under closing tree canopies is necessary and a wide range of functional tree traits should be taken into consideration in future research.

  13. Multiple Trans-Sensing Interactions Affect Meiotically Heritable Epigenetic States at the Maize pl1 Locus

    PubMed Central

    Gross, Stephen M.; Hollick, Jay B.

    2007-01-01

    Interactions between specific maize purple plant1 (pl1) alleles result in heritable changes of gene regulation that are manifested as differences in anthocyanin pigmentation. Transcriptionally repressed states of Pl1-Rhoades alleles (termed Pl′) are remarkably stable and invariably facilitate heritable changes of highly expressed states (termed Pl-Rh) in Pl′/Pl-Rh plants. However, Pl′ can revert to Pl-Rh when hemizygous, when heterozygous with pl1 alleles other than Pl1-Rhoades, or in the absence of trans-acting factors required to maintain repressed states. Cis-linked features of Pl1-Rhoades responsible for these trans-sensing behaviors remain unknown. Here, genetic tests of a pl1 allelic series identify two potentially separate cis-linked features: one facilitating repression of Pl-Rh and another stabilizing Pl′ in trans. Neither function is affected in ethyl-methanesulfonate-induced Pl1-Rhoades derivatives that produce truncated PL1 peptides, indicating that PL1 is unlikely to mediate trans interactions. Both functions, however, are impaired in a spontaneous Pl1-Rhoades derivative that fails to produce detectable pl1 RNA. Pl′-like states can also repress expression of a pl1-W22 allele, but this repression is not meiotically heritable. As the Pl′ state is not associated with unique small RNA species representing the pl1-coding region, the available data suggest that interactions between elements required for transcription underlie Pl1-Rhoades epigenetic behaviors. PMID:17435245

  14. Mother-offspring interactions affect natal dispersal in a lizard.

    PubMed Central

    Le Galliard, Jean-François; Ferrière, Régis; Clobert, Jean

    2003-01-01

    Interactions between relatives operate strong selective pressures on dispersal. Recently, a correlative study in the common lizard (Lacerta vivipara) suggested that natal dispersal might respond plastically to mother-offspring interactions. Here, we describe a factorial experiment supporting this observation. Two crossed treatments were applied to experimental patches of the common lizard: (i) presence versus absence of the mother, inducing a difference of kinship in offspring neighbourhoods; and (ii) high versus low patch density, resulting in two levels of conspecific abundance and modulating the effect of mother presence on the average kinship within a patch. Dispersal of the same cohort of offspring was observed at the juvenile and yearling stages. We found a sex-dependent response of offspring dispersal to the removal of the mother at the two stages. During the juvenile stage, higher dispersal was found in females in the presence of the mother, with males unaffected. During the yearling stage, the responses of both sexes to the presence of the mother opposed each other. In addition, we found a negative relationship between dispersal and patch density at the juvenile stage. No interaction between density and the presence of the mother was detected, which suggests that behavioural responses to kinship and density are disconnected and that kinship is assessed at a small social scale. We discuss the role of competition and inbreeding avoidance to explain the observed pattern. PMID:12816655

  15. Characterization of protein-protein interaction interfaces from a single species.

    PubMed

    Talavera, David; Robertson, David L; Lovell, Simon C

    2011-01-01

    Most proteins attain their biological functions through specific interactions with other proteins. Thus, the study of protein-protein interactions and the interfaces that mediate these interactions is of prime importance for the understanding of biological function. In particular the precise determinants of binding specificity and their contributions to binding energy within protein interfaces are not well understood. In order to better understand these determinants an appropriate description of the interaction surface is needed. Available data from the yeast Saccharomyces cerevisiae allow us to focus on a single species and to use all the available structures, correcting for redundancy, instead of using structural representatives. This allows us to control for potentially confounding factors that may affect sequence propensities. We find a significant contribution of main-chain atoms to protein-protein interactions. These include interactions both with other main-chain and side-chain atoms on the interacting chain. We find that the type of interaction depends on both amino acid and secondary structure type involved in the contact. For example, residues in α-helices and large amino acids are the most likely to be involved in interactions through their side-chain atoms. We find an intriguing homogeneity when calculating the average solvation energy of different areas of the protein surface. Unexpectedly, homo- and hetero-complexes have quite similar results for all analyses. Our findings demonstrate that the manner in which protein-protein interactions are formed is determined by the residue type and the secondary structure found in the interface. However the homogeneity of the desolvation energy despite heterogeneity of interface properties suggests a complex relationship between interface composition and binding energy.

  16. Canopy cover negatively affects arboreal ant species richness in a tropical open habitat.

    PubMed

    Queiroz, A C M; Ribas, C R

    2016-01-01

    We tested the hypothesis of a negative relationship between vegetation characteristics and ant species richness in a Brazilian open vegetation habitat, called candeial. We set up arboreal pitfalls to sample arboreal ants and measured the following environmental variables, which were used as surrogate of environmental heterogeneity: tree richness, tree density, tree height, circumference at the base of the plants, and canopy cover. Only canopy cover had a negative effect on the arboreal ant species richness. Vegetation characteristics and plant species composition are probably homogeneous in candeial, which explains the lack of relationship between other environmental variables and ant richness. Open vegetation habitats harbor a large number of opportunistic and generalist species, besides specialist ants from habitats with high temperatures. An increase in canopy cover decreases sunlight incidence and may cause local microclimatic differences, which negatively affect the species richness of specialist ants from open areas. Canopy cover regulates the richness of arboreal ants in open areas, since only few ant species are able to colonize sites with dense vegetation; most species are present in sites with high temperature and luminosity. Within open vegetation habitats the relationship between vegetation characteristics and species richness seems to be the opposite from closed vegetation areas, like forests.

  17. Multiple vs. single phytoplankton species alter stoichiometry of trophic interaction with zooplankton.

    PubMed

    Plum, Christoph; Hüsener, Matthias; Hillebrand, Helmut

    2015-11-01

    Despite the progress made in explaining trophic interactions through the stoichiometric interplay between consumers and resources, it remains unclear how the number of species in a trophic group influences the effects of elemental imbalances in food webs. Therefore, we conducted a laboratory experiment to test the hypothesis that multispecies producer assemblages alter the nutrient dynamics in a pelagic community. Four algal species were reared in mono- and polycultures under a 2 x 2 factorial combination of light and nutrient supply, thereby contrasting the stoichiometry of trophic interactions involving single vs. multiple producer species. After 9 d, these cultures were fed to the calanoid copepod Acartia tonsa, and we monitored biomass, resource use, and C:N:P stoichiometry in both phyto- and zooplankton. According to our expectations, light and N supply resulted in gradients of phytoplankton biomass and nutrient composition (C:N:P). Significant net diversity effects for algal biomass and C:N:P ratios reflected the greater responsiveness of the phytoplankton polyculture to altered resource supply compared to monocultures. These alterations of elemental ratios were common, and were partly triggered by changes in species frequency in the mixtures and partly by diversity-related changes in resource use. Copepod individual biomass increased under high light (HL) and N-reduced (-N) conditions, when food was high in C:N but low in C:P and N:P, whereas copepod growth was obviously P limited, and copepod stoichiometry was not affected by phytoplankton elemental composition. Correspondingly, copepod individual biomass reflected significant net diversity effects: compared to expectations- derived from monocultures, copepod individuals feeding on algal polycultures remained smaller than predicted under HL and N-sufficient (+N) conditions but grew larger than predicted under HL, -N and low light +N conditions. In conclusion, multiple producer species altered the

  18. Ecological traits affect the response of tropical forest bird species to land-use intensity.

    PubMed

    Newbold, Tim; Scharlemann, Jörn P W; Butchart, Stuart H M; Sekercioğlu, Cağan H; Alkemade, Rob; Booth, Hollie; Purves, Drew W

    2013-01-07

    Land-use change is one of the main drivers of current and likely future biodiversity loss. Therefore, understanding how species are affected by it is crucial to guide conservation decisions. Species respond differently to land-use change, possibly related to their traits. Using pan-tropical data on bird occurrence and abundance across a human land-use intensity gradient, we tested the effects of seven traits on observed responses. A likelihood-based approach allowed us to quantify uncertainty in modelled responses, essential for applying the model to project future change. Compared with undisturbed habitats, the average probability of occurrence of bird species was 7.8 per cent and 31.4 per cent lower, and abundance declined by 3.7 per cent and 19.2 per cent in habitats with low and high human land-use intensity, respectively. Five of the seven traits tested affected the observed responses significantly: long-lived, large, non-migratory, primarily frugivorous or insectivorous forest specialists were both less likely to occur and less abundant in more intensively used habitats than short-lived, small, migratory, non-frugivorous/insectivorous habitat generalists. The finding that species responses to land use depend on their traits is important for understanding ecosystem functioning, because species' traits determine their contribution to ecosystem processes. Furthermore, the loss of species with particular traits might have implications for the delivery of ecosystem services.

  19. Plants are less negatively affected by flooding when growing in species-rich plant communities.

    PubMed

    Wright, Alexandra J; de Kroon, Hans; Visser, Eric J W; Buchmann, Tina; Ebeling, Anne; Eisenhauer, Nico; Fischer, Christine; Hildebrandt, Anke; Ravenek, Janneke; Roscher, Christiane; Weigelt, Alexandra; Weisser, Wolfgang; Voesenek, Laurentius A C J; Mommer, Liesje

    2017-01-01

    Flooding is expected to increase in frequency and severity in the future. The ecological consequences of flooding are the combined result of species-specific plant traits and ecological context. However, the majority of past flooding research has focused on individual model species under highly controlled conditions. An early summer flooding event in a grassland biodiversity experiment in Jena, Germany, provided the opportunity to assess flooding responses of 60 grassland species in monocultures and 16-species mixtures. We examined plant biomass, species-specific traits (plant height, specific leaf area (SLA), root aerenchyma, starch content) and soil porosity. We found that, on average, plant species were less negatively affected by the flood when grown in higher-diversity plots in July 2013. By September 2013, grasses were unaffected by the flood regardless of plant diversity, and legumes were severely negatively affected regardless of plant diversity. Plants with greater SLA and more root aerenchyma performed better in September. Soil porosity was higher in higher-diversity plots and had a positive effect on plant performance. As floods become more frequent and severe in the future, growing flood-sensitive plants in higher-diversity communities and in soil with greater soil aeration may attenuate the most negative effects of flooding.

  20. Bystanders affect the outcome of mother–infant interactions in rhesus macaques

    PubMed Central

    Semple, Stuart; Gerald, Melissa S.; Suggs, Dianne N.

    2009-01-01

    Animal communication involves the transfer of information between a sender and one or more receivers. However, such interactions do not happen in a social vacuum; third parties are typically present, who can potentially eavesdrop upon or intervene in the interaction. The importance of such bystanders in shaping the outcome of communicative interactions has been widely studied in humans, but has only recently received attention in other animal species. Here, we studied bouts of infant crying among rhesus macaques (Macaca mulatta) in order to investigate how the presence of bystanders may affect the outcome of this signalling interaction between infants and mothers. It was hypothesized that, as crying is acoustically aversive, bystanders may be aggressive to the mother or the infant in order to bring the crying bout to a close. Consequently, it was predicted that mothers should acquiesce more often to crying if in the presence of potentially aggressive animals. In line with this prediction, it was found that mothers gave infants access to the nipple significantly more often when crying occurred in the presence of animals that posed a high risk of aggression towards them. Both mothers and infants tended to receive more aggression from bystanders during crying bouts than outside of this time, although such aggression was extremely rare and was received by less than half of the mothers and infants in the study. Mothers were also found to be significantly more aggressive to their infants while the latter were crying than outside of crying bouts. These results provide new insight into the complex dynamics of mother–offspring conflict, and indicate that bystanders may play an important role in shaping the outcome of signalling interactions between infants and their mothers. PMID:19324744

  1. Herbivory affects salt marsh succession dynamics by suppressing the recovery of dominant species.

    PubMed

    Daleo, Pedro; Alberti, Juan; Pascual, Jesús; Canepuccia, Alejandro; Iribarne, Oscar

    2014-05-01

    Disturbance can generate heterogeneous environments and profoundly influence plant diversity by creating patches at different successional stages. Herbivores, in turn, can govern plant succession dynamics by determining the rate of species replacement, ultimately affecting plant community structure. In a south-western Atlantic salt marsh, we experimentally evaluated the role of herbivory in the recovery following disturbance of the plant community and assessed whether herbivory affects the relative importance of sexual and clonal reproduction on these dynamics. Our results show that herbivory strongly affects salt marsh secondary succession by suppressing seedlings and limiting clonal colonization of the dominant marsh grass, allowing subordinate species to dominate disturbed patches. These results demonstrate that herbivores can have an important role in salt marsh community structure and function, and can be a key force during succession dynamics.

  2. Environmental variability uncovers disruptive effects of species' interactions on population dynamics.

    PubMed

    Gudmundson, Sara; Eklöf, Anna; Wennergren, Uno

    2015-08-07

    How species respond to changes in environmental variability has been shown for single species, but the question remains whether these results are transferable to species when incorporated in ecological communities. Here, we address this issue by analysing the same species exposed to a range of environmental variabilities when (i) isolated or (ii) embedded in a food web. We find that all species in food webs exposed to temporally uncorrelated environments (white noise) show the same type of dynamics as isolated species, whereas species in food webs exposed to positively autocorrelated environments (red noise) can respond completely differently compared with isolated species. This is owing to species following their equilibrium densities in a positively autocorrelated environment that in turn enables species-species interactions to come into play. Our results give new insights into species' response to environmental variation. They especially highlight the importance of considering both species' interactions and environmental autocorrelation when studying population dynamics in a fluctuating environment.

  3. Interactions of Metacognition with Motivation and Affect in Self-Regulated Learning: The MASRL Model

    ERIC Educational Resources Information Center

    Efklides, Anastasia

    2011-01-01

    Metacognition, motivation, and affect are components of self-regulated learning (SRL) that interact. The "metacognitive and affective model of self-regulated learning" (the MASRL model) distinguishes two levels of functioning in SRL, namely, the Person level and the Task x Person level. At the Person level interactions between trait-like…

  4. Biogeochemical interactions affecting hepatic trace element levels in aquatic birds

    SciTech Connect

    Moeller, G.

    1996-07-01

    Knowledge of elemental interactions is important to the toxicological assessment of wildlife in the geochemical environment. This study determines the concentrations of Al, As, B, Ba, Be, Cd, Cr, Cu, Fe, Pb, Li, Mg, Mn, Hg, Mo, Ni, Se, Ag, V, and Zn in aquatic bird liver, fish liver, whole bivalves, insects, and waters in several aquatic ecosystems in northern California. There is evidence of strong in vivo and environmental interactions, including the observation of manganese as a possible cofactor or indicator in selenium bioaccumulation. The nearest neighbor selenium correlation in aquatic bird liver tissue that results from this work is Cd-Mn-Se-Hg-As. The correlation of liver selenium to manganese in vivo and the result that the majority of the variance in liver selenium concentration is contained in the manganese term of the regression model relating Se to Cd, Mn, and Hg is new knowledge in the study of aquatic birds. A linear relationship between liver selenium and environmental manganese (water and sediment) is found in the data, suggesting a water chemistry compartmentalization or activation of toxicants. Alternatively, the hepatic concentrations of selenium, manganese, and iron suggest induction of enzymes in response to oxidative stress.

  5. Classification accuracy of algorithms for blood chemistry data for three aquaculture-affected marine fish species.

    PubMed

    Coz-Rakovac, R; Topic Popovic, N; Smuc, T; Strunjak-Perovic, I; Jadan, M

    2009-11-01

    The objective of this study was determination and discrimination of biochemical data among three aquaculture-affected marine fish species (sea bass, Dicentrarchus labrax; sea bream, Sparus aurata L., and mullet, Mugil spp.) based on machine-learning methods. The approach relying on machine-learning methods gives more usable classification solutions and provides better insight into the collected data. So far, these new methods have been applied to the problem of discrimination of blood chemistry data with respect to season and feed of a single species. This is the first time these classification algorithms have been used as a framework for rapid differentiation among three fish species. Among the machine-learning methods used, decision trees provided the clearest model, which correctly classified 210 samples or 85.71%, and incorrectly classified 35 samples or 14.29% and clearly identified three investigated species from their biochemical traits.

  6. Native macrophyte density and richness affect the invasiveness of a tropical poaceae species.

    PubMed

    Michelan, Thaisa S; Thomaz, Sidinei M; Bini, Luis M

    2013-01-01

    The role of the native species richness and density in ecosystem invasibility is a matter of concern for both ecologists and managers. We tested the hypothesis that the invasiveness of Urochloa arrecta (non-native in the Neotropics) is negatively affected by the species richness and abundance of native aquatic macrophytes in freshwater ecosystems. We first created four levels of macrophyte richness in a greenhouse (richness experiment), and we then manipulated the densities of the same native species in a second experiment (density experiment). When the native macrophytes were adults, fragments of U. arrecta were added, and their growth was assessed. Our results from the richness experiment corroborated the hypothesis of a negative relationship between the native species richness and the growth of U. arrecta, as measured by sprout length and root biomass. However, the resistance to invasion was not attributed to the presence of a particular native species with a greater competitive ability. In the density experiment, U. arrecta growth decreased significantly with an increased density of all five of the native species. Density strongly affected the performance of the Poaceae in a negative manner, suggesting that patches that are densely colonized by native macrophytes and less subject to disturbances will be more resistant to invasion than those that are poorly colonized and more commonly subjected to disturbances. Our density experiment also showed that some species exhibit a higher competitive ability than others (sampling effect). Although native richness and abundance clearly limit the colonization and establishment of U. arrecta, these factors cannot completely prevent the invasion of aquatic ecosystems by this Poaceae species.

  7. Provenance, life span, and phylogeny do not affect grass species' responses to nitrogen and phosphorus.

    PubMed

    Seabloom, Eric W; Benfield, Cara D; Borer, Elizabeth T; Stanley, Amanda G; Kaye, Thomas N; Dunwiddie, Peter W

    2011-09-01

    Successful conservation management requires an understanding of how species respond to intervention. Native and exotic species may respond differently to management interventions due to differences arising directly from their origin (i.e., provenance) or indirectly due to biased representations of different life history types (e.g., annual vs. perennial life span) or phylogenetic lineages among provenance (i.e., native or exotic origin) groups. Thus, selection of a successful management regime requires knowledge of the life history and provenance-bias in the local flora and an understanding of the interplay between species characteristics across existing environmental gradients in the landscape. Here we tested whether provenance, phylogeny, and life span interact to determine species distributions along natural gradients of soil chemistry (e.g., soil nitrogen and phosphorus) in 10 upland prairie sites along a 600-km latitudinal transect running from southern Vancouver Island in British Columbia, Canada, to the Willamette Valley in Oregon, USA. We found that soil nitrate, phosphorus, and pH exerted strong control over community composition. However, species distributions along environmental gradients were unrelated to provenance, life span, or phylogenetic groupings. We then used a greenhouse experiment to more precisely measure the response of common grass species to nitrogen and phosphorus supply. As with the field data, species responses to nutrient additions did not vary as a function of provenance, life span, or phylogeny. Native and exotic species differed strongly in the relationship between greenhouse-measured tolerance of low nutrients and field abundance. Native species with the greatest ability to maintain biomass production at low nutrient supply rates were most abundant in field surveys, as predicted by resource competition theory. In contrast, there was no relationship between exotic-species biomass at low nutrient levels and field abundance. The

  8. Cryptococcal Cell Morphology Affects Host Cell Interactions and Pathogenicity

    PubMed Central

    Nielsen, Judith N.; Charlier, Caroline; Baltes, Nicholas J.; Chrétien, Fabrice; Heitman, Joseph; Dromer, Françoise; Nielsen, Kirsten

    2010-01-01

    Cryptococcus neoformans is a common life-threatening human fungal pathogen. The size of cryptococcal cells is typically 5 to 10 µm. Cell enlargement was observed in vivo, producing cells up to 100 µm. These morphological changes in cell size affected pathogenicity via reducing phagocytosis by host mononuclear cells, increasing resistance to oxidative and nitrosative stress, and correlated with reduced penetration of the central nervous system. Cell enlargement was stimulated by coinfection with strains of opposite mating type, and ste3aΔ pheromone receptor mutant strains had reduced cell enlargement. Finally, analysis of DNA content in this novel cell type revealed that these enlarged cells were polyploid, uninucleate, and produced daughter cells in vivo. These results describe a novel mechanism by which C. neoformans evades host phagocytosis to allow survival of a subset of the population at early stages of infection. Thus, morphological changes play unique and specialized roles during infection. PMID:20585559

  9. Genetic interactions affecting touch sensitivity in Caenorhabditis elegans.

    PubMed

    Gu, G; Caldwell, G A; Chalfie, M

    1996-06-25

    At least 13 genes (mec-1, mec-2, mec-4-10, mec-12, mec-14, mec-15, and mec-18) are needed for the response to gentle touch by 6 touch receptor neurons in the nematode Caenorhabditis elegans. Several, otherwise recessive alleles of some of these genes act as dominant enhancer mutations of temperature-sensitive alleles of mec-4, mec-5, mec-6, mec-12, and mec-15. Screens for additional dominant enhancers of mec-4 and mec-5 yielded mutations in previously known genes. In addition, some mec-7 alleles showed allele-specific, dominant suppression of the mec-15 touch-insensitive (Mec) phenotype. The dominant enhancement and suppression exhibited by these mutations suggest that the products of several touch genes interact. These results are consistent with a model, supported by the known sequences of these genes, that almost all of the touch function genes contribute to the mechanosensory apparatus.

  10. The use of affective interaction design in car user interfaces.

    PubMed

    Gkouskos, Dimitrios; Chen, Fang

    2012-01-01

    Recent developments in the car industry have put Human Machine Interfaces under the spotlight. Developing gratifying human-car interactions has become one of the more prominent areas that car manufacturers want to invest in. However, concepts like emotional design remain foreign to the industry. In this study 12 experts on the field of automobile HMI design were interviewed in order to investigate their needs and opinions of emotional design. Results show that emotional design has yet to be introduced for this context of use. Designers need a tool customized for the intricacies of the car HMI field that can provide them with support and guidance so that they can create emotionally attractive experiences for drivers and passengers alike.

  11. Assessment of Natural Regeneration of Mangrove Species at Tsunami Affected Areas in Indonesia and Malaysia

    NASA Astrophysics Data System (ADS)

    Onrizal; Ahmad, A. G.; Mansor, M.

    2017-03-01

    Indian Ocean tsunami caused extensive damage on human life and coastal environments, including fragmented mangroves prior to 2004 tsunami. The natural regeneration of mangrove woody species was assessed in four tidal coasts of Aceh and Peninsular Malaysia during August 2015 to August 2016. A total of 23 mangrove woody species was recorded and they having good ability in term of natural regeneration at tsunami affected areas. The North coast of Aceh was recorded as richest mangrove with 22 species, followed by East coast of Aceh (17 species) and Peninsular Malaysia coast (13 species). In addition, the poorest mangrove was found in West coast of Aceh (7 species). Some species, such as Rhizophora apiculata, R. mucronata, Nypa fruticans, Scaevola taccada and Sonneratia caseolaris are found growing well in all sites. In contrast, Bruguiera cylindrica is only found in West coast of Peninsular Malaysia as same as Ceriops tagal, Phoenix paludosa and Sonneratia ovata are only found in North coast of Aceh. To date, some areas of natural regenerated mangrove were ruined by negative activities, such as illegal cutting and encroachment. Therefore, public consultations and community participations were needed to develop and conserve the important natural assets.

  12. Individual species affect plant traits structure in their surroundings: evidence of functional mechanisms of assembly.

    PubMed

    Chacón-Labella, Julia; de la Cruz, Marcelino; Pescador, David S; Escudero, Adrián

    2016-04-01

    Evaluating community assembly through the use of functional traits is a promising tool for testing predictions arising from Niche and Coexistence theories. Although interactions among neighboring species and their inter-specific differences are known drivers of coexistence with a strong spatial signal, assessing the role of individual species on the functional structure of the community at different spatial scales remains a challenge. Here, we ask whether individual species exert a measurable effect on the spatial organization of different functional traits in local assemblages. We first propose and compute two functions that describe different aspects of functional trait organization around individual species at multiple scales: individual weighted mean area relationship and individual functional diversity area relationship. Secondly, we develop a conceptual model on the relationship and simultaneous variation of these two metrics, providing five alternative scenarios in response to the ability of some target species to modify its neighbor environment and the possible assembly mechanisms involved. Our results show that some species influence the spatial structure of specific functional traits, but their effects were always restricted to the finest spatial scales. In the basis of our conceptual model, the observed patterns point to two main mechanisms driving the functional structure of the community at the fine scale, "biotic" filtering meditated by individual species and resource partitioning driven by indirect facilitation rather than by competitive mechanisms.

  13. Environmental variability uncovers disruptive effects of species' interactions on population dynamics

    PubMed Central

    Gudmundson, Sara; Eklöf, Anna; Wennergren, Uno

    2015-01-01

    How species respond to changes in environmental variability has been shown for single species, but the question remains whether these results are transferable to species when incorporated in ecological communities. Here, we address this issue by analysing the same species exposed to a range of environmental variabilities when (i) isolated or (ii) embedded in a food web. We find that all species in food webs exposed to temporally uncorrelated environments (white noise) show the same type of dynamics as isolated species, whereas species in food webs exposed to positively autocorrelated environments (red noise) can respond completely differently compared with isolated species. This is owing to species following their equilibrium densities in a positively autocorrelated environment that in turn enables species–species interactions to come into play. Our results give new insights into species' response to environmental variation. They especially highlight the importance of considering both species' interactions and environmental autocorrelation when studying population dynamics in a fluctuating environment. PMID:26224705

  14. Tree species composition affects the abundance of rowan (Sorbus aucuparia L.) in urban forests in Finland.

    PubMed

    Hamberg, Leena; Lehvävirta, Susanna; Kotze, D Johan; Heikkinen, Juha

    2015-03-15

    Recent studies have shown a considerable increase in the abundance of rowan (Sorbus aucuparia) saplings in urban forests in Finland, yet the reasons for this increase are not well understood. Here we investigated whether canopy cover or tree species composition, i.e., the basal areas of different tree species in Norway spruce dominated urban forests, affects the abundances of rowan seedlings, saplings and trees. Altogether 24 urban forest patches were investigated. We sampled the number of rowan and other saplings, and calculated the basal areas of trees. We showed that rowan abundance was affected by tree species composition. The basal area of rowan trees (≥ 5 cm in diameter at breast height, dbh) decreased with increasing basal area of Norway spruce, while the cover of rowan seedlings increased with an increase in Norway spruce basal area. However, a decrease in the abundance of birch (Betula pendula) and an increase in the broad-leaved tree group (Acer platanoides, Alnus glutinosa, Alnus incana, Amelanchier spicata, Prunus padus, Quercus robur, Rhamnus frangula and Salix caprea) coincided with a decreasing number of rowans. Furthermore, rowan saplings were scarce in the vicinity of mature rowan trees. Although it seems that tree species composition has an effect on rowan, the relationship between rowan saplings and mature trees is complex, and therefore we conclude that regulating tree species composition is not an easy way to keep rowan thickets under control in urban forests in Finland.

  15. Fhit interaction with ferredoxin reductase triggers generation of reactive oxygen species and apoptosis of cancer cells.

    PubMed

    Trapasso, Francesco; Pichiorri, Flavia; Gaspari, Marco; Palumbo, Tiziana; Aqeilan, Rami I; Gaudio, Eugenio; Okumura, Hiroshi; Iuliano, Rodolfo; Di Leva, Giampiero; Fabbri, Muller; Birk, David E; Raso, Cinzia; Green-Church, Kari; Spagnoli, Luigi G; Venuta, Salvatore; Huebner, Kay; Croce, Carlo M

    2008-05-16

    Fhit protein is lost in most cancers, its restoration suppresses tumorigenicity, and virus-mediated FHIT gene therapy induces apoptosis and suppresses tumors in preclinical models. We have used protein cross-linking and proteomics methods to characterize a Fhit protein complex involved in triggering Fhit-mediated apoptosis. The complex includes Hsp60 and Hsp10 that mediate Fhit stability and may affect import into mitochondria, where it interacts with ferredoxin reductase, responsible for transferring electrons from NADPH to cytochrome P450 via ferredoxin. Viral-mediated Fhit restoration increases production of intracellular reactive oxygen species, followed by increased apoptosis of lung cancer cells under oxidative stress conditions; conversely, Fhit-negative cells escape apoptosis, carrying serious oxidative DNA damage that may contribute to an increased mutation rate. Characterization of Fhit interacting proteins has identified direct effectors of the Fhit-mediated apoptotic pathway that is lost in most cancers through loss of Fhit.

  16. Fermentation condition outweighed truffle species in affecting volatile organic compounds analyzed by chromatographic fingerprint system.

    PubMed

    Tang, Ya-Jie; Wang, Guan; Li, Yuan-Yuan; Zhong, Jian-Jiang

    2009-08-04

    The influences of fermentation conditions and truffle species (i.e., Tuber melanosporum, Tuber sinense, Tuber indicum, and Tuber aestivum) on the volatile organic compounds (VOCs) originated from truffle fermentation mycelia were studied by using chromatographic fingerprint system for the first time. Gas chromatography combined with statistical methods including similarity analysis and hierarchical cluster analysis was applied to develop chromatographic fingerprint system for truffle VOCs evaluation. Fermentation conditions affected the VOCs from truffle fermentation mycelia much more significantly than truffle species. This indicated that it is possible to adjust the aroma of truffle fermentation mycelia similar with the natural fruiting-body through the control of fermentation process.

  17. Southwestern Cooperative Educational Laboratory Interaction Observation Schedule (SCIOS): A System for Analyzing Teacher-Pupil Interaction in the Affective Domain.

    ERIC Educational Resources Information Center

    Bemis, Katherine A.; Liberty, Paul G.

    The Southwestern Cooperative Interaction Observation Schedule (SCIOS) is a classroom observation instrument designed to record pupil-teacher interaction. The classification of pupil behavior is based on Krathwohl's (1964) theory of the three lowest levels of the affective domain. The levels are (1) receiving: the learner should be sensitized to…

  18. Deviation from niche optima affects the nature of plant-plant interactions along a soil acidity gradient.

    PubMed

    He, Lei; Cheng, Lulu; Hu, Liangliang; Tang, Jianjun; Chen, Xin

    2016-01-01

    There is increasing recognition of the importance of niche optima in the shift of plant-plant interactions along environmental stress gradients. Here, we investigate whether deviation from niche optima would affect the outcome of plant-plant interactions along a soil acidity gradient (pH = 3.1, 4.1, 5.5 and 6.1) in a pot experiment. We used the acid-tolerant species Lespedeza formosa Koehne as the neighbouring plant and the acid-tolerant species Indigofera pseudotinctoria Mats. or acid-sensitive species Medicago sativa L. as the target plants. Biomass was used to determine the optimal pH and to calculate the relative interaction index (RII). We found that the relationships between RII and the deviation of soil pH from the target's optimal pH were linear for both target species. Both targets were increasingly promoted by the neighbour as pH values deviated from their optima; neighbours benefitted target plants by promoting soil symbiotic arbuscular mycorrhizal fungi, increasing soil organic matter or reducing soil exchangeable aluminium. Our results suggest that the shape of the curve describing the relationship between soil pH and facilitation/competition depends on the soil pH optima of the particular species.

  19. Food stoichiometry affects the outcome of Daphnia–parasite interaction

    PubMed Central

    Aalto, Sanni L; Pulkkinen, Katja

    2013-01-01

    Phosphorus (P) is an essential nutrient for growth in consumers. P-limitation and parasite infection comprise one of the most common stressor pairs consumers confront in nature. We conducted a life-table study using a Daphnia–microsporidian parasite model, feeding uninfected or infected Daphnia with either P-sufficient or P-limited algae, and assessed the impact of the two stressors on life-history traits of the host. Both infection and P-limitation negatively affected some life-history traits tested. However, under P-limitation, infected animals had higher juvenile growth rate as compared with uninfected animals. All P-limited individuals died before maturation, regardless of infection. The numbers of spore clusters of the microsporidian parasite did not differ in P-limited or P-sufficient hosts. P-limitation, but not infection, decreased body phosphorus content and ingestion rates of Daphnia tested in separate experiments. As parasite spore production did not suffer even under extreme P-limitation, our results suggest that parasite was less limited by P than the host. We discuss possible interpretations concerning the stoichiometrical demands of parasite and suggest that our results are explained by parasite-driven changes in carbon (C) allocation of the hosts. We conclude that the impact of nutrient starvation and parasite infection on consumers depends not only on the stoichiometric demands of host but also those of the parasite. PMID:23762513

  20. Vibration Feedback Latency Affects Material Perception during Rod Tapping Interactions.

    PubMed

    Hachisu, Taku; Kajimoto, Hiroyuki

    2016-11-15

    We investigated the effect of vibration feedback latency on material perception during a tapping interaction using a rod device. When a user taps a surface, the perception of the material can be modulated by providing a decaying sinusoidal vibration at the moment of contact. To achieve this haptic material augmentation on a touchscreen, a system that can measure the approach velocity and provide vibration with low latency is required. To this end, we developed a touchscreen system that is capable of measuring the approach velocity and providing vibration feedback via a rod device with latency of 0.1 ms. Using this system, we experimentally measured the human detection threshold of the vibration feedback latency adopting a psychophysical approach. We further investigated the effect of latency on the perception of the material using a subjective questionnaire. Results show that the threshold was around 5.5 ms and the latency made the user feel that the surface is soft. In addition, users reported bouncing and denting sensations induced by the latency.

  1. Physicochemical properties of quinoa flour as affected by starch interactions.

    PubMed

    Li, Guantian; Zhu, Fan

    2017-04-15

    There has been growing interest in whole grain quinoa flour for new product development due to the unique nutritional benefits. The quality of quinoa flour is much determined by the properties of its major component starch as well as non-starch components. In this study, composition and physicochemical properties of whole grain flour from 7 quinoa samples have been analyzed. Flour properties have been correlated to the flour composition and the properties of isolated quinoa starches through chemometrics. Great variations in chemical composition, swelling power, water soluble index, enzyme susceptibility, pasting, gel texture, and thermal properties of the flour have been observed. Correlation analysis showed that thermal properties and enzyme susceptibility of quinoa flour are highly influenced by the starch. Interactions of starch with non-starch components, including lipids, protein, dietary fibre, phenolics, and minerals, greatly impacted the flour properties. For example, peak gelatinization temperature of the flour is positively correlated to that of the starch (r=0.948, p<0.01) and negatively correlated to the lipid content (r=-0.951, p<0.01). Understanding the roles of starch and other components in physicochemical properties of quinoa flour provides a basis for better utilization of this specialty crop.

  2. Tree species diversity interacts with elevated CO2 to induce a greater root system response.

    PubMed

    Smith, Andrew R; Lukac, Martin; Bambrick, Michael; Miglietta, Franco; Godbold, Douglas L

    2013-01-01

    As a consequence of land-use change and the burning of fossil fuels, atmospheric concentrations of CO2 are increasing and altering the dynamics of the carbon cycle in forest ecosystems. In a number of studies using single tree species, fine root biomass has been shown to be strongly increased by elevated CO2 . However, natural forests are often intimate mixtures of a number of co-occurring species. To investigate the interaction between tree mixture and elevated CO2 , Alnus glutinosa, Betula pendula and Fagus sylvatica were planted in areas of single species and a three species polyculture in a free-air CO2 enrichment study (BangorFACE). The trees were exposed to ambient or elevated CO2 (580 μmol mol(-1) ) for 4 years. Fine and coarse root biomass, together with fine root turnover and fine root morphological characteristics were measured. Fine root biomass and morphology responded differentially to the elevated CO2 at different soil depths in the three species when grown in monocultures. In polyculture, a greater response to elevated CO2 was observed in coarse roots to a depth of 20 cm, and fine root area index to a depth of 30 cm. Total fine root biomass was positively affected by elevated CO2 at the end of the experiment, but not by species diversity. Our data suggest that existing biogeochemical cycling models parameterized with data from species grown in monoculture may be underestimating the belowground response to global change.

  3. Evolutionary factors affecting the cross-species utility of newly developed microsatellite markers in seabirds.

    PubMed

    Moodley, Yoshan; Masello, Juan F; Cole, Theresa L; Calderon, Luciano; Munimanda, Gopi K; Thali, Marco R; Alderman, Rachael; Cuthbert, Richard J; Marin, Manuel; Massaro, Melanie; Navarro, Joan; Phillips, Richard A; Ryan, Peter G; Suazo, Cristián G; Cherel, Yves; Weimerskirch, Henri; Quillfeldt, Petra

    2015-09-01

    Microsatellite loci are ideal for testing hypotheses relating to genetic segregation at fine spatio-temporal scales. They are also conserved among closely related species, making them potentially useful for clarifying interspecific relationships between recently diverged taxa. However, mutations at primer binding sites may lead to increased nonamplification, or disruptions that may result in decreased polymorphism in nontarget species. Furthermore, high mutation rates and constraints on allele size may also with evolutionary time, promote an increase in convergently evolved allele size classes, biasing measures of interspecific genetic differentiation. Here, we used next-generation sequencing to develop microsatellite markers from a shotgun genome sequence of the sub-Antarctic seabird, the thin-billed prion (Pachyptila belcheri), that we tested for cross-species amplification in other Pachyptila and related sub-Antarctic species. We found that heterozygosity decreased and the proportion of nonamplifying loci increased with phylogenetic distance from the target species. Surprisingly, we found that species trees estimated from interspecific FST provided better approximations of mtDNA relationships among the studied species than those estimated using DC , even though FST was more affected by null alleles. We observed a significantly nonlinear second order polynomial relationship between microsatellite and mtDNA distances. We propose that the loss of linearity with increasing mtDNA distance stems from an increasing proportion of homoplastic allele size classes that are identical in state, but not identical by descent. Therefore, despite high cross-species amplification success and high polymorphism among the closely related Pachyptila species, we caution against the use of microsatellites in phylogenetic inference among distantly related taxa.

  4. Remnant Trees Affect Species Composition but Not Structure of Tropical Second-Growth Forest

    PubMed Central

    Sandor, Manette E.; Chazdon, Robin L.

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2–3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests (“control plots”). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields. PMID:24454700

  5. Remnant trees affect species composition but not structure of tropical second-growth forest.

    PubMed

    Sandor, Manette E; Chazdon, Robin L

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2-3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests ("control plots"). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields.

  6. Tree Species Composition and Harvest Intensity Affect Herbivore Density and Leaf Damage on Beech, Fagus sylvatica, in Different Landscape Contexts.

    PubMed

    Mangels, Jule; Blüthgen, Nico; Frank, Kevin; Grassein, Fabrice; Hilpert, Andrea; Mody, Karsten

    2015-01-01

    Most forests are exposed to anthropogenic management activities that affect tree species composition and natural ecosystem processes. Changes in ecosystem processes such as herbivory depend on management intensity, and on regional environmental conditions and species pools. Whereas influences of specific forest management measures have already been addressed for different herbivore taxa on a local scale, studies considering effects of different aspects of forest management across different regions are rare. We assessed the influence of tree species composition and intensity of harvesting activities on arthropod herbivores and herbivore-related damage to beech trees, Fagus sylvatica, in 48 forest plots in three regions of Germany. We found that herbivore abundance and damage to beech trees differed between regions and that - despite the regional differences - density of tree-associated arthropod taxa and herbivore damage were consistently affected by tree species composition and harvest intensity. Specifically, overall herbivore damage to beech trees increased with increasing dominance of beech trees - suggesting the action of associational resistance processes - and decreased with harvest intensity. The density of leaf chewers and mines was positively related to leaf damage, and several arthropod groups responded to beech dominance and harvest intensity. The distribution of damage patterns was consistent with a vertical shift of herbivores to higher crown layers during the season and with higher beech dominance. By linking quantitative data on arthropod herbivore abundance and herbivory with tree species composition and harvesting activity in a wide variety of beech forests, our study helps to better understand the influence of forest management on interactions between a naturally dominant deciduous forest tree and arthropod herbivores.

  7. Tree Species Composition and Harvest Intensity Affect Herbivore Density and Leaf Damage on Beech, Fagus sylvatica, in Different Landscape Contexts

    PubMed Central

    Mangels, Jule; Blüthgen, Nico; Frank, Kevin; Grassein, Fabrice; Hilpert, Andrea; Mody, Karsten

    2015-01-01

    Most forests are exposed to anthropogenic management activities that affect tree species composition and natural ecosystem processes. Changes in ecosystem processes such as herbivory depend on management intensity, and on regional environmental conditions and species pools. Whereas influences of specific forest management measures have already been addressed for different herbivore taxa on a local scale, studies considering effects of different aspects of forest management across different regions are rare. We assessed the influence of tree species composition and intensity of harvesting activities on arthropod herbivores and herbivore-related damage to beech trees, Fagus sylvatica, in 48 forest plots in three regions of Germany. We found that herbivore abundance and damage to beech trees differed between regions and that – despite the regional differences - density of tree-associated arthropod taxa and herbivore damage were consistently affected by tree species composition and harvest intensity. Specifically, overall herbivore damage to beech trees increased with increasing dominance of beech trees – suggesting the action of associational resistance processes – and decreased with harvest intensity. The density of leaf chewers and mines was positively related to leaf damage, and several arthropod groups responded to beech dominance and harvest intensity. The distribution of damage patterns was consistent with a vertical shift of herbivores to higher crown layers during the season and with higher beech dominance. By linking quantitative data on arthropod herbivore abundance and herbivory with tree species composition and harvesting activity in a wide variety of beech forests, our study helps to better understand the influence of forest management on interactions between a naturally dominant deciduous forest tree and arthropod herbivores. PMID:25938417

  8. Climate change threatens endangered plant species by stronger and interacting water-related stresses

    NASA Astrophysics Data System (ADS)

    Bartholomeus, Ruud P.; Witte, Jan-Philip M.; van Bodegom, Peter M.; van Dam, Jos C.; Aerts, Rien

    2011-12-01

    Atmospheric CO2-concentration, temperature and rainfall variability are all expected to increase in the near future. The resulting increased dynamics of soil moisture contents, together with increased plant physiological demands for both oxygen and water, will lead to an increased occurrence of wet and dry extremes of plant stresses, i.e., of oxygen and drought stress, respectively, alone and in interaction. The use of indirect environmental variables in previous studies and a focus on individual stresses rather than their combined effects has hampered understanding of the causal impact of climate change on plant species composition through changes in abiotic site conditions. Here, we use process-based simulations of oxygen and drought stresses in conjunction with a downscaled national version of IPCC scenarios in order to show that these stresses will increase (on average by ˜20% at sites where both stresses occur) in a warmer and more variable future (2050) climate. These two types of stresses will increasingly coincide, i.e. both stresses will occur more often (but not at the same time) within a single vegetation plot. We further show that this increased coincidence of water-related stresses will negatively affect the future occurrence of currently endangered plant species (causing a reduction of ˜16%), while apparently no such decrease will occur among common species. Individual stresses did not appear to affect the occurrence of endangered plant species. Consequently, our study demonstrates that species that are already threatened under the current climate will suffer most from the effects of climate change.

  9. Interactions among invaders: community and ecosystem effects of multiple invasive species in an experimental aquatic system.

    PubMed

    Johnson, Pieter T J; Olden, Julian D; Solomon, Christopher T; Vander Zanden, M Jake

    2009-02-01

    With ecosystems increasingly supporting multiple invasive species, interactions among invaders could magnify or ameliorate the undesired consequences for native communities and ecosystems. We evaluated the individual and combined effects of rusty crayfish (Orconectes rusticus) and Chinese mystery snails [Bellamya (=Cipangopaludina) chinensis] on native snail communities (Physa, Helisoma and Lymnaea sp.) and ecosystem attributes (algal chlorophyll a and nutrient concentrations). Both invaders are widespread in the USA and commonly co-occur within northern temperate lakes, underscoring the importance of understanding their singular and joint effects. An outdoor mesocosm experiment revealed that while the two invaders had only weakly negative effects upon one another, both negatively affected the abundance and biomass of native snails, and their combined presence drove one native species to extinction and reduced a second by >95%. Owing to its larger size and thicker shell, adult Bellamya were protected from crayfish attack relative to native species (especially Physa and Lymnaea), suggesting the co-occurrence of these invaders in nature could have elevated consequences for native communities. The per capita impacts of Orconectes (a snail predator) on native snails were substantially greater than those of Bellamya (a snail competitor). Crayfish predation also had a cascading effect by reducing native snail biomass, leading to increased periphyton growth. Bellamya, in contrast, reduced periphyton biomass, likely causing a reduction in growth by native lymnaeid snails. Bellamya also increased water column N:P ratio, possibly because of a low P excretion rate relative to native snail species. Together, these findings highlight the importance of understanding interactions among invasive species, which can have significant community- and ecosystem-level effects.

  10. Tree species diversity affects decomposition through modified micro-environmental conditions across European forests.

    PubMed

    Joly, François-Xavier; Milcu, Alexandru; Scherer-Lorenzen, Michael; Jean, Loreline-Katia; Bussotti, Filippo; Dawud, Seid Muhie; Müller, Sandra; Pollastrini, Martina; Raulund-Rasmussen, Karsten; Vesterdal, Lars; Hättenschwiler, Stephan

    2017-02-09

    Different tree species influence litter decomposition directly through species-specific litter traits, and indirectly through distinct modifications of the local decomposition environment. Whether these indirect effects on decomposition are influenced by tree species diversity is presently not clear. We addressed this question by studying the decomposition of two common substrates, cellulose paper and wood sticks, in a total of 209 forest stands of varying tree species diversity across six major forest types at the scale of Europe. Tree species richness showed a weak but positive correlation with the decomposition of cellulose but not with that of wood. Surprisingly, macroclimate had only a minor effect on cellulose decomposition and no effect on wood decomposition despite the wide range in climatic conditions among sites from Mediterranean to boreal forests. Instead, forest canopy density and stand-specific litter traits affected the decomposition of both substrates, with a particularly clear negative effect of the proportion of evergreen tree litter. Our study suggests that species richness and composition of tree canopies modify decomposition indirectly through changes in microenvironmental conditions. These canopy-induced differences in the local decomposition environment control decomposition to a greater extent than continental-scale differences in macroclimatic conditions.

  11. Macroinvertebrate abundance, water chemistry, and wetland characteristics affect use of wetlands by avian species in Maine

    USGS Publications Warehouse

    Longcore, J.R.; McAuley, D.G.; Pendleton, G.W.; Bennatti, C.R.; Mingo, T.M.; Stromborg, K.L.; Hanson, Alan; Kerekes, Joseph; Paquet, Julie

    2006-01-01

    Our objective was to determine use by avian species (e.g., piscivores, marsh birds, waterfowl, selected passerines) of 29 wetlands in areas with low ( 5.51. All years combined use of wetlands by broods was greater on wetlands with pH 5.51 that supported 21.8% of the broods. High mean brood density was associated with mean number of Insecta per wetland. For lentic wetlands created by beaver, those habitats contained vegetative structure and nutrients necessary to provide cover to support invertebrate populations that are prey of omnivore and insectivore species. The fishless status of a few wetlands may have affected use by some waterfowl species and obligate piscivores.

  12. Quantification of Heavy Metals in Mining Affected Soil and Their Bioaccumulation in Native Plant Species.

    PubMed

    Nawab, Javed; Khan, Sardar; Shah, Mohammad Tahir; Khan, Kifayatullah; Huang, Qing; Ali, Roshan

    2015-01-01

    Several anthropogenic and natural sources are considered as the primary sources of toxic metals in the environment. The current study investigates the level of heavy metals contamination in the flora associated with serpentine soil along the Mafic and Ultramafic rocks northern-Pakistan. Soil and wild native plant species were collected from chromites mining affected areas and analyzed for heavy metals (Cr, Ni, Fe, Mn, Co, Cu and Zn) using atomic absorption spectrometer (AAS-PEA-700). The heavy metal concentrations were significantly (p < 0.01) higher in mine affected soil as compared to reference soil, however Cr and Ni exceeded maximum allowable limit (250 and 60 mg kg(-1), respectively) set by SEPA for soil. Inter-metal correlations between soil, roots and shoots showed that the sources of contamination of heavy metals were mainly associated with chromites mining. All the plant species accumulated significantly higher concentrations of heavy metals as compared to reference plant. The open dumping of mine wastes can create serious problems (food crops and drinking water contamination with heavy metals) for local community of the study area. The native wild plant species (Nepeta cataria, Impatiens bicolor royle, Tegetis minuta) growing on mining affected sites may be used for soil reclamation contaminated with heavy metals.

  13. Species-abundance--seed-size patterns within a plant community affected by grazing disturbance.

    PubMed

    Wu, Gao-lin; Shang, Zhan-huan; Zhu, Yuan-jun; Ding, Lu-ming; Wang, Dong

    2015-04-01

    Seed size has been advanced as a key factor that influences the dynamics of plant communities, but there are few empirical or theoretical predictions of how community dynamics progress based on seed size patterns. Information on the abundance of adults, seedlings, soil seed banks, seed rains, and the seed mass of 96 species was collected in alpine meadows of the Qinghai-Tibetan Plateau (China), which had different levels of grazing disturbance. The relationships between seed-mass-abundance patterns for adults, seedlings, the soil seed bank, and seed rain in the plant community were evaluated using regression models. Results showed that grazing levels affected the relationship between seed size and abundance properties of adult species, seedlings, and the soil seed bank, suggesting that there is a shift in seed-size--species-abundance relationships as a response to the grazing gradient. Grazing had no effect on the pattern of seed-size-seed-rain-abundance at four grazing levels. Grazing also had little effect on the pattern of seed-size--species-abundance and pattern of seed-size--soil-seed-bank-abundance in meadows with no grazing, light grazing, and moderate grazing), but there was a significant negative effect in meadows with heavy grazing. Grazing had little effect on the pattern of seed-size--seedling-abundance with no grazing, but had significant negative effects with light, moderate, and heavy grazing, and the |r| values increased with grazing levels. This indicated that increasing grazing pressure enhanced the advantage of smaller-seeded species in terms of the abundances of adult species, seedlings, and soil seed banks, whereas only the light grazing level promoted the seed rain abundance of larger-seeded species in the plant communities. This study suggests that grazing disturbances are favorable for increasing the species abundance for smaller-seeded species but not for the larger-seeded species in an alpine meadow community. Hence, there is a clear

  14. Interactions between Artificial Gravity, Affected Physiological Systems, and Nutrition

    NASA Technical Reports Server (NTRS)

    Heer, Martina; Baecker, Natalie; Zwart, Sara; Smith, Scott M.

    2007-01-01

    Malnutrition, either by insufficient supply of some nutrients or by overfeeding has a profound effect on the health of an organism. Therefore, optimal nutrition is mandatory on Earth (1 g), in microgravity and also when applying artificial gravity to the human system. Immobilization like in microgravity or bed rest also has a profound effect on different physiological systems, like body fluid regulation, the cardiovascular, the musculoskeletal, the immunological system and others. Up to now there is no countermeasure available which is effective to counteract cardiovascular deconditioning (rf. Chapter 5) together with maintenance of the musculoskeletal system in a rather short period of time. Gravity seems therefore to be one of the main stimuli to keep these systems and application of certain duration of artificial gravity per day by centrifugation has often been proposed as a very potential countermeasure against the weakening of the physiological systems. Up to now, neither optimal intensity nor optimal length of application of artificial gravity has been studied sufficiently to recommend a certain, effective and efficient protocol. However, as shown in chapter 5 on cardiovascular system, in chapter 6 on the neuromuscular system and chapter 7 (bone and connective system) artificial gravity has a very high potential to counteract any degradation caused by immobilization. But, nutrient supply -which ideally should match the actual needs- will interact with these changes and therefore has also to be taken into account. It is well known that astronauts beside the Skylab missions- were and are still not optimally nourished during their stay in space (Bourland et al. 2000;Heer et al. 1995;Heer et al. 2000b;Smith et al. 1997;Smith & Lane 1999;Smith et al. 2001;Smith et al. 2005). It has also been described anecdotally that astronauts have lower appetites. One possible explanation could be altered taste and smell sensations during space flight, although in some early

  15. Spatiotemporal interactions between wild boar and cattle: implications for cross-species disease transmission.

    PubMed

    Barasona, Jose A; Latham, M Cecilia; Acevedo, Pelayo; Armenteros, Jose A; Latham, A David M; Gortazar, Christian; Carro, Francisco; Soriguer, Ramon C; Vicente, Joaquin

    2014-12-12

    Controlling infectious diseases at the wildlife/livestock interface is often difficult because the ecological processes driving transmission between wildlife reservoirs and sympatric livestock populations are poorly understood. Thus, assessing how animals use their environment and how this affects interspecific interactions is an important factor in determining the local risk for disease transmission and maintenance. We used data from concurrently monitored GPS-collared domestic cattle and wild boar (Sus scrofa) to assess spatiotemporal interactions and associated implications for bovine tuberculosis (TB) transmission in a complex ecological and epidemiological system, Doñana National Park (DNP, South Spain). We found that fine-scale spatial overlap of cattle and wild boar was seasonally high in some habitats. In general, spatial interactions between the two species were highest in the marsh-shrub ecotone and at permanent water sources, whereas shrub-woodlands and seasonal grass-marshlands were areas with lower predicted relative interactions. Wild boar and cattle generally used different resources during winter and spring in DNP. Conversely, limited differences in resource selection during summer and autumn, when food and water availability were limiting, resulted in negligible spatial segregation and thus probably high encounter rates. The spatial gradient in potential overlap between the two species across DNP corresponded well with the spatial variation in the observed incidence of TB in cattle and prevalence of TB in wild boar. We suggest that the marsh-shrub ecotone and permanent water sources act as important points of TB transmission in our system, particularly during summer and autumn. Targeted management actions are suggested to reduce potential interactions between cattle and wild boar in order to prevent disease transmission and design effective control strategies.

  16. Shrub encroachment affects mammalian carnivore abundance and species richness in semiarid rangelands

    NASA Astrophysics Data System (ADS)

    Blaum, Niels; Rossmanith, Eva; Popp, Alexander; Jeltsch, Florian

    2007-01-01

    Shrub encroachment due to overgrazing has led to dramatic changes of savanna landscapes and is considered to be one of the most threatening forms of rangeland degradation e.g. via habitat fragmentation. Mammalian carnivores are particularly vulnerable to local extinction in fragmented landscapes. However, our understanding of how shrub encroachment affects mammalian carnivores is poor. Here we investigated the relative sensitivities of ten native carnivores to different levels of shrub cover ranging from low (<5%) to high shrub cover (>25%) in 20 southern Kalahari rangeland sites. Relative abundance of carnivores was monitored along 40 sand transects (5 m × 250 m) for each site. Our results show that increasing shrub cover affects carnivore species differently. African wild cats, striped polecats, cape foxes and suricates were negatively affected, whereas we found hump-shaped responses for yellow mongooses, bat-eared foxes and small-spotted genets with maximum abundance at shrub covers between 10 and 18%. In contrast, black-backed jackals, slender mongooses and small spotted cats were not significantly affected by increasing shrub cover. However, a negative impact of high shrub cover above 18% was congruent for all species. We conclude that intermediate shrub cover (10-18%) in savanna landscapes sustain viable populations of small carnivores.

  17. Leader charisma and affective team climate: the moderating role of the leader's influence and interaction.

    PubMed

    Hernández Baeza, Ana; Araya Lao, Cristina; García Meneses, Juliana; González Romá, Vicente

    2009-11-01

    In this study, we evaluate the role of leader charisma in fostering positive affective team climate and preventing negative affective climate. The analysis of a longitudinal database of 137 bank branches by means of hierarchical moderated regression shows that leader charisma has a stronger effect on team optimism than on team tension. In addition, the leader's influence and the frequency of leader-team interaction moderate the relationship between charisma and affective climate. However, whereas the leader's influence enhances the relationship between leader charisma and positive affective climate, the frequency of interaction has counterproductive effects.

  18. Are trade-offs among species' ecological interactions scale dependent? A test using pitcher-plant inquiline species.

    PubMed

    Kneitel, Jamie M

    2012-01-01

    Trade-offs among species' ecological interactions is a pervasive explanation for species coexistence. The traits associated with trade-offs are typically measured to mechanistically explain species coexistence at a single spatial scale. However, species potentially interact at multiple scales and this may be reflected in the traits among coexisting species. I quantified species' ecological traits associated with the trade-offs expected at both local (competitive ability and predator tolerance) and regional (competitive ability and colonization rate) community scales. The most common species (four protozoa and a rotifer) from the middle trophic level of a pitcher plant (Sarracenia purpurea) inquiline community were used to link species traits to previously observed patterns of species diversity and abundance. Traits associated with trade-offs (competitive ability, predator tolerance, and colonization rate) and other ecological traits (size, growth rate, and carrying capacity) were measured for each of the focal species. Traits were correlated with one another with a negative relationship indicative of a trade-off. Protozoan and rotifer species exhibited a negative relationship between competitive ability and predator tolerance, indicative of coexistence at the local community scale. There was no relationship between competitive ability and colonization rate. Size, growth rate, and carrying capacity were correlated with each other and the trade-off traits: Size was related to both competitive ability and predator tolerance, but growth rate and carrying capacity were correlated with predator tolerance. When partial correlations were conducted controlling for size, growth rate and carrying capacity, the trade-offs largely disappeared. These results imply that body size is the trait that provides the basis for ecological interactions and trade-offs. Altogether, this study showed that the examination of species' traits in the context of coexistence at different scales

  19. Season and light affect constitutive defenses of understory shrub species against folivorous insects

    NASA Astrophysics Data System (ADS)

    Karolewski, Piotr; Giertych, Marian J.; Żmuda, Michał; Jagodziński, Andrzej M.; Oleksyn, Jacek

    2013-11-01

    Understory shrubs contribute to overall species diversity, providing habitat and forage for animals, influence soil chemistry and forest microclimate. However, very little is known about the chemical defense of various shrub species against folivorous insects. Using six shrub species, we tested how seasonal changes and light conditions affect their constitutive defense to insect damage. We monitored leaf perforation, concentrations of total phenols, condensed tannins, nitrogen (N), and total nonstructural carbohydrates (TNC). Leaf damage caused by insects was low in Sambucus nigra, Cornus sanguinea, and Frangula alnus, intermediate in Corylus avellana and Prunus serotina, and high in Prunus padus. Leaves of all the species, when growing in high light conditions, had high concentrations of defense metabolites. Except for C. avellana, leaves of the other shrub species growing in full sun were less injured than those in shade. This may be due to higher concentrations of defense metabolites and lower concentrations of nitrogen. Similar patterns of the effects of light on metabolites studied and N were observed for leaves with varying location within the crown of individual shrubs (from the top of the south direction to the bottom of the north), as for leaves from shrubs growing in full sun and shrubs in the shade of canopy trees. A probable cause of the greater damage of more sunlit leaves of C. avellana was the fact that they were herbivorized mostly by Altica brevicollis, a specialist insect that prefers plant tissues with a high TNC level and is not very sensitive to a high level of phenolic compounds.

  20. Factors affecting reproductive success in three entomophilous orchid species in Hungary.

    PubMed

    Vojtkó, Anna E; Sonkoly, Judit; Lukács, Balázs András; Molnár V, Attila

    2015-06-01

    The reproductive success of orchids is traditionally estimated by determining the fruit-set of individuals. Here, we investigated both the fruit and the seed production of three orchid species and the factors that may affect individual fruit-set, like pollination strategy, individual traits or the annual amount of precipitation. The species [Dactylorhiza sambucina (L.) Soó, Dactylorhiza majalis (Rchb.) P. F. Hunt & Summerhayes and Platanthera bifolia (L.) L. C. M. Richard] were studied in three consecutive years (2010-2012) in the Bükk Mountains, Hungary. All three species were proved to be non-autogamous by a bagging experiment. Data analyses showed significant differences between seed numbers but not between fruit-sets of species. There was no statistical difference in individual reproductive success between wet and dry years, however, the effect of the annual amount of precipitation is significant on the population level. Comparison of published fruit-set data revealed accordance with our results in P. bifolia, but not in D. sambucina and D. majalis. We assume that the surprisingly high fruit-set values of the two Dactylorhiza species may be due to the fact that the pollination crisis reported from Western European countries is not an actual problem in the Bükk Mountains, Hungary.

  1. Infant affective reactions to the resumption of maternal interaction after the still-face.

    PubMed

    Weinberg, M K; Tronick, E Z

    1996-06-01

    To investigate infants' reactions to the Face-to-Face Still-Face Paradigm and in particular the reunion episode, 50 6-month-olds' affective, behavioral, and physiologic reactions were recorded and analyzed. Infants reacted to the still-face with negative affect, a drop in vagal tone, and an increase in heart rate. By contrast, they reacted to the reunion episode with a mixed pattern of positive and negative affect. There was a carryover of negative affect from the still-face, an increase in fussiness and crying, and a rebound of positive affect. During this episode, the infants' heart rate and vagal tone returned to initial levels. The data indicate that infant affective displays are specifically related to different interactive events, but that their physiologic reactions do not show the same level of specificity. The findings also highlight the complexity of the affective and reparatory processes that take place in mother-infant interactions.

  2. Does deciduous tree species identity affect carbon storage in temperate soils?

    NASA Astrophysics Data System (ADS)

    Jungkunst, Hermann; Schleuß, Per; Heitkamp, Felix

    2015-04-01

    Forest soils contribute roughly 70 % to the global terrestrial soil organic carbon (SOC) pool and thus play a vital role in the global carbon cycle. It is less clear, however, whether temperate tree species identity affects SOC storage beyond the coarse differentiation between coniferous and deciduous trees. The most important driver for soil SOC storage definitely is the fine mineral fraction (clay and fine silt) because of its high sorption ability. It is difficult to disentangle any additional biotic effects since clay and silt vary considerably in nature. For experimental approaches, the process of soil carbon accumulation is too slow and, therefore, sound results cannot be expected for decades. Here we will present our success to distinguish between the effects of fine particle content (abiotic) and tree species composition (biotic) on the SOC pool in an old-growth broad-leaved forest plots along a tree diversity gradient , i.e., 1- (beech), 3- (plus ash and lime tree)- and 5-(plus maple and hornbeam) species. The particle size fractions were separated first and then the carbon concentrations of each fraction was measured. Hence, the carbon content per unit clay was not calculated, as usually done, but directly measured. As expected, the variation in SOC content was mainly explained by the variations in clay content but not entirely. We found that the carbon concentration per unit clay and fine silt in the subsoil was by 30-35% higher in mixed than in monospecific stands indicating a significant species identity or species diversity effect on C stabilization. In contrast to the subsoil, no tree species effects was identified for the topsoil. Indications are given that the mineral phase was already carbon saturated and thus left no more room for a possible biotic effect. Underlying processes must remain speculative, but we will additionally present our latest microcosm results, including isotopic signatures, to underpin the proposed deciduous tree species

  3. Predicting species interactions from edge responses: mongoose predation on hawksbill sea turtle nests in fragmented beach habitat.

    PubMed

    Leighton, Patrick A; Horrocks, Julia A; Krueger, Barry H; Beggs, Jennifer A; Kramer, Donald L

    2008-11-07

    Because species respond differently to habitat boundaries and spatial overlap affects encounter rates, edge responses should be strong determinants of spatial patterns of species interactions. In the Caribbean, mongooses (Herpestes javanicus) prey on hawksbill sea turtle (Eretmochelys imbricata) eggs. Turtles nest in both open sand and vegetation patches, with a peak in nest abundance near the boundary between the two microhabitats; mongooses rarely leave vegetation. Using both artificial nests and hawksbill nesting data, we examined how the edge responses of these species predict the spatial patterns of nest mortality. Predation risk was strongly related to mongoose abundance but was not affected by nest density or habitat type. The product of predator and prey edge response functions accurately described the observed pattern of total prey mortality. Hawksbill preference for vegetation edge becomes an ecological trap in the presence of mongooses. This is the first study to predict patterns of predation directly from continuous edge response functions of interacting species, establishing a link between models of edge response and species interactions.

  4. Bottom-up and top-down human impacts interact to affect a protected coastal Chilean marsh.

    PubMed

    Fariña, José M; He, Qiang; Silliman, Brian R; Bertness, Mark D

    2016-03-01

    Many ecosystems, even in protected areas, experience multiple anthropogenic impacts. While anthropogenic modification of bottom-up (e.g., eutrophication) and top-down (e.g., livestock grazing) forcing often co-occurs, whether these factors counteract or have additive or synergistic effects on ecosystems is poorly understood. In a Chilean bio-reserve, we examined the interactive impacts of eutrophication and illegal livestock grazing on plant growth with a 4-yr fertilization by cattle exclusion experiment. Cattle grazing generally decreased plant biomass, but had synergistic, additive, and antagonistic interactions with fertilization in the low, middle, and high marsh zones, respectively. In the low marsh, fertilization increased plant biomass by 112%, cattle grazing decreased it by 96%, and together they decreased plant biomass by 77%. In the middle marsh, fertilization increased plant biomass by 47%, cattle grazing decreased it by 37%, and together they did not affect plant biomass. In the high marsh, fertilization and cattle grazing decreased plant biomass by 81% and 92%, respectively, but together they increased plant biomass by 42%. These interactions were also found to be species specific. Different responses of plants to fertilization and cattle grazing were likely responsible for these variable interactions. Thus, common bottom-up and top-down human impacts can interact in different ways to affect communities even within a single ecosystem. Incorporating this knowledge into conservation actions will improve ecosystem management in a time when ecosystems are increasingly challenged by multiple interacting human impacts.

  5. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants.

    PubMed

    Ossola, Alessandro; Nash, Michael A; Christie, Fiona J; Hahs, Amy K; Livesley, Stephen J

    2015-01-01

    Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size.

  6. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

    PubMed Central

    Nash, Michael A.; Christie, Fiona J.; Hahs, Amy K.; Livesley, Stephen J.

    2015-01-01

    Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size. PMID:26528416

  7. Morphology predicts species' functional roles and their degree of specialization in plant–frugivore interactions

    PubMed Central

    Dehling, D. Matthias; Schaefer, H. Martin; Böhning-Gaese, Katrin; Schleuning, Matthias

    2016-01-01

    Species' functional roles in key ecosystem processes such as predation, pollination or seed dispersal are determined by the resource use of consumer species. An interaction between resource and consumer species usually requires trait matching (e.g. a congruence in the morphologies of interaction partners). Species' morphology should therefore determine species' functional roles in ecological processes mediated by mutualistic or antagonistic interactions. We tested this assumption for Neotropical plant–bird mutualisms. We used a new analytical framework that assesses a species's functional role based on the analysis of the traits of its interaction partners in a multidimensional trait space. We employed this framework to test (i) whether there is correspondence between the morphology of bird species and their functional roles and (ii) whether morphologically specialized birds fulfil specialized functional roles. We found that morphological differences between bird species reflected their functional differences: (i) bird species with different morphologies foraged on distinct sets of plant species and (ii) morphologically distinct bird species fulfilled specialized functional roles. These findings encourage further assessments of species' functional roles through the analysis of their interaction partners, and the proposed analytical framework facilitates a wide range of novel analyses for network and community ecology. PMID:26817779

  8. The Dynamic Reactance Interaction - How Vested Interests Affect People's Experience, Behavior, and Cognition in Social Interactions.

    PubMed

    Steindl, Christina; Jonas, Eva

    2015-01-01

    In social interactions, individuals may sometimes pursue their own interests at the expense of their interaction partner. Such self-interested behaviors impose a threat to the interaction partner's freedom to act. The current article investigates this threat in the context of interdependence and reactance theory. We explore how vested interests influence reactance process stages of an advisor-client interaction. We aim to explore the interactional process that evolves. In two studies, participants took the perspective of a doctor (advisor) or a patient (client). In both studies we incorporated a vested interest. In Study 1 (N = 82) we found that in response to a vested interest of their interaction partner, patients indicated a stronger experience of reactance, more aggressive behavioral intentions, and more biased cognitions than doctors. A serial multiple mediation revealed that a vested interest engendered mistrust toward the interaction partner and this mistrust led to an emerging reactance process. Study 2 (N = 207) further demonstrated that doctors expressed their reactance in a subtle way: they revealed a classic confirmation bias when searching for additional information on their preliminary decision preference, indicating stronger defense motivation. We discuss how these findings can help us to understand how social interactions develop dynamically.

  9. The Anthelmintic Ingredient Moxidectin Negatively Affects Seed Germination of Three Temperate Grassland Species

    PubMed Central

    Eichberg, Carsten; Wohde, Manuel; Müller, Kerstin; Rausch, Anja; Scherrmann, Christina; Scheuren, Theresa; Düring, Rolf-Alexander; Donath, Tobias W.

    2016-01-01

    In animal farming, anthelmintics are regularly applied to control gastrointestinal nematodes. There is plenty of evidence that also non-target organisms, such as dung beetles, are negatively affected by residues of anthelmintics in faeces of domestic ungulates. By contrast, knowledge about possible effects on wild plants is scarce. To bridge this gap of knowledge, we tested for effects of the common anthelmintic formulation Cydectin and its active ingredient moxidectin on seed germination. We conducted a feeding experiment with sheep and germination experiments in a climate chamber. Three wide-spread plant species of temperate grasslands (Centaurea jacea, Galium verum, Plantago lanceolata) were studied. We found significant influences of both, Cydectin and moxidectin, on germination of the tested species. Across species, both formulation and active ingredient solely led to a decrease in germination percentage and synchrony of germination and an increase in mean germination time with the formulation showing a more pronounced response pattern. Our study shows for the first time that anthelmintics have the potential to negatively affect plant regeneration. This has practical implications for nature conservation since our results suggest that treatments of livestock with anthelmintics should be carefully timed to not impede endozoochorous seed exchange between plant populations. PMID:27846249

  10. SPECIES INTERACTIONS BETWEEN ESTUARINE DETRITIVORES: INHIBITION OR FACILITATION?

    EPA Science Inventory

    Native Hawaiian estuarine detritivores; the prawn Macrobrachium grandimanus, and the neritid gastropod Neritina vespertina, were maintained in flow-through microcosms with conditioned leaves from two riparian tree species, Hau (Hibiscus tiliaceus) and guava (Psidium guajava). Th...

  11. Plant water use affects competition for nitrogen: why drought favors invasive species in California.

    PubMed

    Everard, Katherine; Seabloom, Eric W; Harpole, W Stanley; de Mazancourt, Claire

    2010-01-01

    Abstract: Classic resource competition theory typically treats resource supply rates as independent; however, nutrient supplies can be affected by plants indirectly, with important consequences for model predictions. We demonstrate this general phenomenon by using a model in which competition for nitrogen is mediated by soil moisture, with competitive outcomes including coexistence and multiple stable states as well as competitive exclusion. In the model, soil moisture regulates nitrogen availability through soil moisture dependence of microbial processes, leaching, and plant uptake. By affecting water availability, plants also indirectly affect nitrogen availability and may therefore alter the competitive outcome. Exotic annual species from the Mediterranean have displaced much of the native perennial grasses in California. Nitrogen and water have been shown to be potentially limiting in this system. We parameterize the model for a Californian grassland and show that soil moisture-mediated competition for nitrogen can explain the annual species' dominance in drier areas, with coexistence expected in wetter regions. These results are concordant with larger biogeographic patterns of grassland invasion in the Pacific states of the United States, in which annual grasses have invaded most of the hot, dry grasslands in California but perennial grasses dominate the moister prairies of northern California, Oregon, and Washington.

  12. Factors affecting toxicity test endpoints in sensitive life stages of native Gulf of Mexico species.

    PubMed

    Echols, B S; Smith, A J; Rand, G M; Seda, B C

    2015-05-01

    Indigenous species are less commonly used in laboratory aquatic toxicity tests compared with standard test species due to (1) limited availability lack of requisite information necessary for their acclimation and maintenance under laboratory conditions and (2) lack of information on their sensitivity and the reproducibility of toxicity test results. As part of the Natural Resource Damage Assessment aquatic toxicity program in response to the Deepwater Horizon Oil incident (2010), sensitive life stages of native Gulf of Mexico species were evaluated in laboratory toxicity tests to determine the potential effects of the spill. Fish (n = 5) and invertebrates (n = 2) selected for this program include the following: the Florida pompano (Trachinotus carolinus), red drum (Sciaenops ocellatus), spotted sea trout (Cynoscion nebulosus), cobia (Rachycentron canadum), red porgy (Pagrus pagrus), blue crab (Callinectes sapidus), and the common moon jellyfish (Aurelia aurita). Initially in the program, to establish part of the background information, acute tests with reference toxicants (CdCl2, KCl, CuSO4) were performed with each species to establish data on intraspecies variability and test precision as well as identify other factors that may affect toxicity results. Median lethal concentration (LC50) values were calculated for each acute toxicity test with average LC50 values ranging from 248 to 862 mg/L for fish exposures to potassium chloride. Variability between test results was determined for each species by calculating the coefficient of variation (%CV) based on LC50 values. CVs ranged from 11.2 % for pompano (96-h LC50 value) to 74.8 % for red porgy 24-h tests. Cadmium chloride acute toxicity tests with the jellyfish A. aurita had the lowest overall CV of 3.6 %. By understanding acute toxicity to these native organisms from a compound with known toxicity ranges and the variability in test results, acute tests with nonstandard species can be better interpreted and used

  13. Alexithymic characteristics and patient-therapist interaction: a video analysis of facial affect display.

    PubMed

    Rasting, Marcus; Brosig, Burkhard; Beutel, Manfred E

    2005-01-01

    Alexithymia as a disorder of affect regulation entails a patient's reduced ability to process emotional information. The purpose of this study was to evaluate the impact of alexithymia [as measured by the Toronto Alexithymia Scale (TAS)-26, German version] on affective correlates in a dyadic therapeutic interaction (as recorded by the Emotional Facial Action Coding System). Interviews with 12 in-patients with various psychosomatic disorders (anxiety, depression, somatisation) were videotaped and evaluated for facial affect display. The corresponding emotional reactions of the therapists (split screen) were recorded separately. Patients with high alexithymia scores (TAS-26 total score) tended to display less aggressive affects than those with low scores. The therapists' predominant emotional reaction to alexithymic patients was contempt. Our findings underscore the deep-rooted nature of alexithymia as a disorder of affect regulation. Since facial affects play a major role in the regulation of emotional interaction, this disorder may evoke negative reactions of potential caregivers.

  14. Human-Computer Interaction: A Review of the Research on Its Affective and Social Aspects.

    ERIC Educational Resources Information Center

    Deaudelin, Colette; Dussault, Marc; Brodeur, Monique

    2003-01-01

    Discusses a review of 34 qualitative and non-qualitative studies related to affective and social aspects of student-computer interactions. Highlights include the nature of the human-computer interaction (HCI); the interface, comparing graphic and text types; and the relation between variables linked to HCI, mainly trust, locus of control,…

  15. Are they talking to me? Cognitive and affective effects of interactivity in politicians' twitter communication.

    PubMed

    Lee, Eun-Ju; Shin, Soo Yun

    2012-10-01

    The present study investigated when and how the level of interactivity in politicians' Twitter communication affects the public's cognitive and affective reactions. In a Web-based experiment (n=264), participants viewed a high profile male politician's Twitter page, wherein he was either actively responding to his followers' questions (high interactivity) or mostly posting messages on his own (low interactivity). Exposure to the high-interactivity Twitter page induced a stronger sense of direct conversation with the candidate (social presence), but only among less affiliative individuals who usually avoid social interaction. Heightened social presence, in turn, led to more positive overall evaluations of the candidate and a stronger intention to vote for him. Although those in the high-interactivity condition generated more positive thoughts, they had fewer issue-related thoughts and exhibited poorer recognition of the issues mentioned by the candidate.

  16. 50 CFR 402.45 - Alternative consultation on FIFRA actions that are not likely to adversely affect listed species...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Counterpart Regulations Governing Actions by the U.S... that are not likely to adversely affect listed species or critical habitat. 402.45 Section...

  17. 50 CFR 402.45 - Alternative consultation on FIFRA actions that are not likely to adversely affect listed species...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Counterpart Regulations Governing Actions by the U.S... that are not likely to adversely affect listed species or critical habitat. 402.45 Section...

  18. 50 CFR 402.45 - Alternative consultation on FIFRA actions that are not likely to adversely affect listed species...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Counterpart Regulations Governing Actions by the U.S... that are not likely to adversely affect listed species or critical habitat. 402.45 Section...

  19. 50 CFR 402.45 - Alternative consultation on FIFRA actions that are not likely to adversely affect listed species...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Counterpart Regulations Governing Actions by the U.S... that are not likely to adversely affect listed species or critical habitat. 402.45 Section...

  20. 50 CFR 402.45 - Alternative consultation on FIFRA actions that are not likely to adversely affect listed species...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Counterpart Regulations Governing Actions by the U.S... that are not likely to adversely affect listed species or critical habitat. 402.45 Section...

  1. Fine-scale urbanization affects Odonata species diversity in ponds of a megacity (Paris, France)

    NASA Astrophysics Data System (ADS)

    Jeanmougin, Martin; Leprieur, Fabien; Loïs, Grégoire; Clergeau, Philippe

    2014-08-01

    Current developments in urban ecology include very few studies focused on pond ecosystems, though ponds are recognized as biodiversity hotspots. Using Odonata as an indicator model, we explored changes in species composition in ponds localized along an urban gradient of a megacity (Paris, France). We then assessed the relative importance of local- and landscape-scale variables in shaping Odonata α-diversity patterns using a model-averaging approach. Analyses were performed for adult (A) and adult plus exuviae (AE) census data. At 26 ponds, we recorded 657 adults and 815 exuviae belonging to 17 Odonata species. The results showed that the Odonata species assemblage composition was not determined by pond localization along the urban gradient. Similarly, pond characteristics were found to be similar among urban, suburban and periurban ponds. The analyses of AE census data revealed that fine-scale urbanization (i.e., increased density of buildings surrounding ponds) negatively affects Odonata α-diversity. In contrast, pond localization along the urban gradient weakly explained the α-diversity patterns. Several local-scale variables, such as the coverage of submerged macrophytes, were found to be significant drivers of Odonata α-diversity. Together, these results show that the degree of urbanization around ponds must be considered instead of pond localization along the urban gradient when assessing the potential impacts of urbanization on Odonata species diversity. This work also indicates the importance of exuviae sampling in understanding the response of Odonata to urbanization.

  2. Microbial Environment Affects Innate Immunity in Two Closely Related Earthworm Species Eisenia andrei and Eisenia fetida

    PubMed Central

    Dvořák, Jiří; Mančíková, Veronika; Pižl, Václav; Elhottová, Dana; Šilerová, Marcela; Roubalová, Radka; Škanta, František; Procházková, Petra; Bilej, Martin

    2013-01-01

    Survival of earthworms in the environment depends on their ability to recognize and eliminate potential pathogens. This work is aimed to compare the innate defense mechanisms of two closely related earthworm species, Eisenia andrei and Eisenia fetida, that inhabit substantially different ecological niches. While E. andrei lives in a compost and manure, E. fetida can be found in the litter layer in forests. Therefore, the influence of environment-specific microbiota on the immune response of both species was followed. Firstly, a reliable method to discern between E. andrei and E. fetida based on species-specific primers for cytochrome c oxidase I (COI) and stringent PCR conditions was developed. Secondly, to analyze the immunological profile in both earthworm species, the activity and expression of lysozyme, pattern recognition protein CCF, and antimicrobial proteins with hemolytic function, fetidin and lysenins, have been assessed. Whereas, CCF and lysozyme showed only slight differences in the expression and activity, fetidin/lysenins expression as well as the hemolytic activity was considerably higher in E. andrei as compared to E. fetida. The expression of fetidin/lysenins in E. fetida was not affected upon the challenge with compost microbiota, suggesting more substantial changes in the regulation of the gene expression. Genomic DNA analyses revealed significantly higher level of fetidin/lysenins (determined using universal primer pairs) in E. andrei compared to E. fetida. It can be hypothesized that E. andrei colonizing compost as a new habitat acquired an evolutionary selection advantage resulting in a higher expression of antimicrobial proteins. PMID:24223917

  3. Microbial environment affects innate immunity in two closely related earthworm species Eisenia andrei and Eisenia fetida.

    PubMed

    Dvořák, Jiří; Mančíková, Veronika; Pižl, Václav; Elhottová, Dana; Silerová, Marcela; Roubalová, Radka; Skanta, František; Procházková, Petra; Bilej, Martin

    2013-01-01

    Survival of earthworms in the environment depends on their ability to recognize and eliminate potential pathogens. This work is aimed to compare the innate defense mechanisms of two closely related earthworm species, Eisenia andrei and Eisenia fetida, that inhabit substantially different ecological niches. While E. andrei lives in a compost and manure, E. fetida can be found in the litter layer in forests. Therefore, the influence of environment-specific microbiota on the immune response of both species was followed. Firstly, a reliable method to discern between E. andrei and E. fetida based on species-specific primers for cytochrome c oxidase I (COI) and stringent PCR conditions was developed. Secondly, to analyze the immunological profile in both earthworm species, the activity and expression of lysozyme, pattern recognition protein CCF, and antimicrobial proteins with hemolytic function, fetidin and lysenins, have been assessed. Whereas, CCF and lysozyme showed only slight differences in the expression and activity, fetidin/lysenins expression as well as the hemolytic activity was considerably higher in E. andrei as compared to E. fetida. The expression of fetidin/lysenins in E. fetida was not affected upon the challenge with compost microbiota, suggesting more substantial changes in the regulation of the gene expression. Genomic DNA analyses revealed significantly higher level of fetidin/lysenins (determined using universal primer pairs) in E. andrei compared to E. fetida. It can be hypothesized that E. andrei colonizing compost as a new habitat acquired an evolutionary selection advantage resulting in a higher expression of antimicrobial proteins.

  4. The outcomes of most aggressive interactions among closely related bird species are asymmetric.

    PubMed

    Martin, Paul R; Freshwater, Cameron; Ghalambor, Cameron K

    2017-01-01

    Aggressive interactions among closely related species are common, and can play an important role as a selective pressure shaping species traits and assemblages. The nature of this selective pressure depends on whether the outcomes of aggressive contests are asymmetric between species (i.e., one species is consistently dominant), yet few studies have estimated the prevalence of asymmetric versus symmetric outcomes to aggressive contests. Here we use previously published data involving 26,212 interactions between 270 species pairs of birds from 26 taxonomic families to address the question: How often are aggressive interactions among closely related bird species asymmetric? We define asymmetry using (i) the proportion of contests won by one species, and (ii) statistical tests for asymmetric outcomes of aggressive contests. We calculate these asymmetries using data summed across different sites for each species pair, and compare results to asymmetries calculated using data separated by location. We find that 80% of species pairs had aggressive outcomes where one species won 80% or more of aggressive contests. We also find that the majority of aggressive interactions among closely related species show statistically significant asymmetries, and above a sample size of 52 interactions, all outcomes are asymmetric following binomial tests. Species pairs with dominance data from multiple sites showed the same dominance relationship across locations in 93% of the species pairs. Overall, our results suggest that the outcome of aggressive interactions among closely related species are usually consistent and asymmetric, and should thus favor ecological and evolutionary strategies specific to the position of a species within a dominance hierarchy.

  5. The outcomes of most aggressive interactions among closely related bird species are asymmetric

    PubMed Central

    Freshwater, Cameron; Ghalambor, Cameron K.

    2017-01-01

    Aggressive interactions among closely related species are common, and can play an important role as a selective pressure shaping species traits and assemblages. The nature of this selective pressure depends on whether the outcomes of aggressive contests are asymmetric between species (i.e., one species is consistently dominant), yet few studies have estimated the prevalence of asymmetric versus symmetric outcomes to aggressive contests. Here we use previously published data involving 26,212 interactions between 270 species pairs of birds from 26 taxonomic families to address the question: How often are aggressive interactions among closely related bird species asymmetric? We define asymmetry using (i) the proportion of contests won by one species, and (ii) statistical tests for asymmetric outcomes of aggressive contests. We calculate these asymmetries using data summed across different sites for each species pair, and compare results to asymmetries calculated using data separated by location. We find that 80% of species pairs had aggressive outcomes where one species won 80% or more of aggressive contests. We also find that the majority of aggressive interactions among closely related species show statistically significant asymmetries, and above a sample size of 52 interactions, all outcomes are asymmetric following binomial tests. Species pairs with dominance data from multiple sites showed the same dominance relationship across locations in 93% of the species pairs. Overall, our results suggest that the outcome of aggressive interactions among closely related species are usually consistent and asymmetric, and should thus favor ecological and evolutionary strategies specific to the position of a species within a dominance hierarchy. PMID:28070465

  6. How environmental conditions affect canopy leaf-level photosynthesis in four deciduous tree species

    SciTech Connect

    Bassow, S.L.; Bazzaz, F.A.

    1998-12-01

    Species composition of temperate forests vary with successional age and seems likely to change in response to significant global climate change. Because photosynthesis rates in co-occurring tree species can differ in their sensitivity to environmental conditions, these changes in species composition are likely to alter the carbon dynamics of temperate forests. To help improve their understanding of such atmosphere-biosphere interactions, the authors explored changes in leaf-level photosynthesis in a 60--70 yr old temperate mixed-deciduous forest in Petersham, Massachusetts (USA). Diurnally and seasonally varying environmental conditions differentially influenced in situ leaf-level photosynthesis rates in the canopies of four mature temperate deciduous tree species: red oak (Quercus rubra), red maple (Acer rubrum), white birch (Betula papyrifera), and yellow birch (Betula alleghaniensis). The authors measured in situ photosynthesis at two heights within the canopies through a diurnal time course on 7 d over two growing seasons. They simultaneously measured a suite of environmental conditions surrounding the leaf at the time of each measurement. The authors used path analysis to examine the influence of environmental factors on in situ photosynthesis in the tree canopies.

  7. Mechanisms driving change: altered species interactions and ecosystem function through global warming.

    PubMed

    Traill, Lochran W; Lim, Matthew L M; Sodhi, Navjot S; Bradshaw, Corey J A

    2010-09-01

    1. We review the mechanisms behind ecosystem functions, the processes that facilitate energy transfer along food webs, and the major processes that allow the cycling of carbon, oxygen and nitrogen, and use case studies to show how these have already been, and will continue to be, altered by global warming. 2. Increased temperatures will affect the interactions between heterotrophs and autotrophs (e.g. pollination and seed dispersal), and between heterotrophs (e.g. predators-prey, parasites/pathogens-hosts), with generally negative ramifications for important ecosystem services (functions that provide direct benefit to human society such as pollination) and potential for heightened species co-extinction rates. 3. Mitigation of likely impacts of warming will require, in particular, the maintenance of species diversity as insurance for the provision of basic ecosystem services. Key to this will be long-term monitoring and focused research that seek to maintain ecosystem resilience in the face of global warming. 4. We provide guidelines for pursuing research that quantifies the nexus between ecosystem function and global warming. These include documentation of key functional species groups within systems, and understanding the principal outcomes arising from direct and indirect effects of a rapidly warming environment. Localized and targeted research and monitoring, complemented with laboratory work, will determine outcomes for resilience and guide adaptive conservation responses and long-term planning.

  8. Evaluating how species niche modelling is affected by partial distributions with an empirical case

    NASA Astrophysics Data System (ADS)

    Carretero, Miguel A.; Sillero, Neftalí

    2016-11-01

    Ecological niche models (ENMs) will successfully identify a species' ecological niche, provided that important assumptions are fulfilled, namely environment equilibrium and niche equality across the distribution. Violations may seriously affect ENM reliability, leading to erroneous biogeographic conclusions and inappropriate conservation prioritisation. We evaluate the robustness of ENMs against incomplete knowledge of distribution with a real example, the threatened Iberian lizard Podarcis carbonelli, whose distribution was gradually discovered over a long time period. We used several ENM methods for presence-only data (Maxent, ENFA, Bioclim, and Domain) to infer the realised ecological niche at two spatial resolutions (1 km and 200 m). The distribution data were split into four partial datasets corresponding to separate subranges: Central System (CS); Viseu-Aveiro (VA); Atlantic coast (AC); and Doñana (DO). We then accumulated the datasets following the species discovery sequence: CS + VA, CS + VA + AC, and CS + VA + AC + DO. Niche equivalence and similarity between partial models were compared using Ecospat. ENMs were strongly affected by the violation of niche equilibrium; only the VA subrange forecasts the complete species range. ENMs were also sensitive to the violation of niche equality: only VA models were similar to the Iberian model, altitude being the most important variable followed by annual precipitation, maximum temperature in July, and annual radiation. When the ENMs were applied only to the first subrange discovered (CS), only the VA area was predicted, while the other subranges might have remained unknown, thus compromising conservation strategies. As assumptions of niche equilibrium and equality were violated, likely owing to the species' ecological multimodality, the models generated were biased and of limited predictive value. ENMs are useful tools in biogeography and conservation, but only if their basal assumptions are achieved. Partial

  9. Modularity Reveals the Tendency of Arbuscular Mycorrhizal Fungi To Interact Differently with Generalist and Specialist Plant Species in Gypsum Soils

    PubMed Central

    Torrecillas, Emma; del Mar Alguacil, Maria; Roldán, Antonio; Díaz, Gisela; Montesinos-Navarro, Alicia

    2014-01-01

    Patterns in plant–soil biota interactions could be influenced by the spatial distribution of species due to soil conditions or by the functional traits of species. Gypsum environments usually constitute a mosaic of heterogeneous soils where gypsum and nongypsum soils are imbricated at a local scale. A case study of the interactions of plants with arbuscular mycorrhizal fungi (AMF) in gypsum environments can be illustrative of patterns in biotic interactions. We hypothesized that (i) soil characteristics might affect the AMF community and (ii) there are differences between the AMF communities (modules) associated with plants exclusive to gypsum soils (gypsophytes) and those associated with plants that show facultative behavior on gypsum and/or marly-limestone soils (gypsovags). We used indicator species and network analyses to test for differences between the AMF communities harbored in gypsophyte and gypsovag plants. We recorded 46 operational taxonomic units (OTUs) belonging to nine genera of Glomeromycota. The indicator species analysis showed two OTUs preferentially associating with gypsum soils and three OTUs preferentially associating with marly-limestone soils. Modularity analysis revealed that soil type can be a major factor shaping AMF communities, and some AMF groups showed a tendency to interact differently with plants that had distinct ecological strategies (gypsophytes and gypsovags). Characterization of ecological networks can be a valuable tool for ascertaining the potential influence of above- and below-ground biotic interactions (plant-AMF) on plant community composition. PMID:24973074

  10. The Cattle-Wolf Dilemma: Interactions among Three Protected Species

    NASA Astrophysics Data System (ADS)

    Becker, Nir; Farja, Yanay

    2017-02-01

    This paper utilizes economic valuation to offer a new perspective on livestock rancher—predator conflicts. While most studies have considered losses to the species directly involved, i.e., cattle and wolves ( Canis lupus), we take into account other species that are threatened by efforts to protect livestock. In this case, vultures ( Gyps fulvus) and gazelles ( Gazella gazella), both endangered species, are either poisoned (vultures) or suffer from habitat fragmentation (gazelles) in the Upper Galilee region in Israel. Since the ecological value of these species is unobserved in the marketplace, we use the contingent valuation method to quantify the loss incurred from damage to protected species: wolves, vultures and gazelles. This method uses surveys of a representative sample from the population to generate estimates for use and non-use values of animals and other components of the natural environment. These value estimates are then used to compare between different measures that address the problem: either protect cattle herds by building anti-wolf fences and taking other protective measures, or compensating ranchers for their losses from wolf depredations. Our analysis suggests that while it is optimal from the ranchers' point of view to invest in protective measures such as fences, dogs and guards against wolves, it is not in society's best interest. A cost-benefit analysis taking into account all the ecological values finds a higher net benefit to society from a relatively small amount of protection, coupled with compensation to the farmers for depredations.

  11. The Cattle-Wolf Dilemma: Interactions among Three Protected Species.

    PubMed

    Becker, Nir; Farja, Yanay

    2017-02-01

    This paper utilizes economic valuation to offer a new perspective on livestock rancher-predator conflicts. While most studies have considered losses to the species directly involved, i.e., cattle and wolves (Canis lupus), we take into account other species that are threatened by efforts to protect livestock. In this case, vultures (Gyps fulvus) and gazelles (Gazella gazella), both endangered species, are either poisoned (vultures) or suffer from habitat fragmentation (gazelles) in the Upper Galilee region in Israel. Since the ecological value of these species is unobserved in the marketplace, we use the contingent valuation method to quantify the loss incurred from damage to protected species: wolves, vultures and gazelles. This method uses surveys of a representative sample from the population to generate estimates for use and non-use values of animals and other components of the natural environment. These value estimates are then used to compare between different measures that address the problem: either protect cattle herds by building anti-wolf fences and taking other protective measures, or compensating ranchers for their losses from wolf depredations. Our analysis suggests that while it is optimal from the ranchers' point of view to invest in protective measures such as fences, dogs and guards against wolves, it is not in society's best interest. A cost-benefit analysis taking into account all the ecological values finds a higher net benefit to society from a relatively small amount of protection, coupled with compensation to the farmers for depredations.

  12. Species interactions among larval mosquitoes: context dependence across habitat gradients.

    PubMed

    Juliano, Steven A

    2009-01-01

    Biotic interactions involving mosquito larvae are context dependent, with effects of interactions on populations altered by ecological conditions. Relative impacts of competition and predation change across a gradient of habitat size and permanence. Asymmetrical competition is common and ecological context changes competitive advantage, potentially facilitating landscape-level coexistence of competitors. Predator effects on mosquito populations sometimes depend on habitat structure and on emergent effects of multiple predators, particularly interference among predators. Nonlethal effects of predators on mosquito oviposition, foraging, and life history are common, and their consequences for populations and for mosquito-borne disease are poorly understood. Context-dependent beneficial effects of detritus shredders on mosquitoes occur in container habitats, but these interactions appear to involve more than simple resource modification by shredders. Investigations of context-dependent interactions among mosquito larvae will yield greater understanding of mosquito population dynamics and provide useful model systems for testing theories of context dependence in communities.

  13. Species Interactions Among Larval Mosquitoes: Context Dependence Across Habitat Gradients

    PubMed Central

    Juliano, Steven A.

    2009-01-01

    Biotic interactions involving mosquito larvae are context dependent, with effects of interactions on populations altered by ecological conditions. Relative impacts of competition and predation change across a gradient of habitat size and permanence. Asymmetrical competition is common and ecological context changes competitive advantage, potentially facilitating landscape-level coexistence of competitors. Predator effects on mosquito populations sometimes depend on habitat structure and on emergent effects of multiple predators, particularly interference among predators. Nonlethal effects of predators on mosquito oviposition, foraging, and life history are common, and their consequences for populations and for mosquito-borne disease are poorly understood. Context-dependent beneficial effects of detritus shredders on mosquitoes occur in container habitats, but these interactions appear to involve more than simple resource modification by shredders. Investigations of context-dependent interactions among mosquito larvae will yield greater understanding of mosquito population dynamics and provide useful model systems for testing theories of context dependence in communities. PMID:19067629

  14. Breast epithelial tissue morphology is affected in 3D cultures by species-specific collagen-based extracellular matrix.

    PubMed

    Dhimolea, Eugen; Soto, Ana M; Sonnenschein, Carlos

    2012-11-01

    Collagen-based gels have been widely used to determine the factors that regulate branching morphogenesis in the mammary gland. The patterns of biomechanical gradients and collagen reorganization influence the shape and orientation of epithelial structures in three-dimensional (3D) conditions. We explored in greater detail whether collagen type I fibers with distinct biomechanical and fiber-assembling properties, isolated from either bovine or rat tail tendon, differentially affected the epithelial phenotype in a tissue culture model of the human breast. Rat tail collagen fibers were densely packed into significantly longer and thicker bundles compared to those of the bovine type (average fascicle length 7.35 and 2.29 μm, respectively; p = 0.0001), indicating increased fiber alignment and biomechanical enablement in the former. MCF10A epithelial cells formed elaborated branched tubular structures in bovine but only nonbranched ducts and acini in rat tail collagen matrices. Ductal branching in bovine collagen was associated with interactions between neighboring structures mediated through packed collagen fibers; these fiber-mediated interactions were absent in rat tail collagen gels. Normal breast fibroblasts increased the final size and number of ducts only in rat tail collagen gels while not affecting branching. Our results suggest that the species of origin of collagen used in organotypic cultures may influence epithelial differentiation into alveolar or ductal structures and the patterns of epithelial branching. These observations underscore the importance of considering the species of origin and fiber alignment properties of collagen when engineering branching organs in 3D matrices and interpreting their role in the tissue phenotype.

  15. Resource-dependent attenuation of species interactions during bacterial succession.

    PubMed

    Rivett, Damian W; Scheuerl, Thomas; Culbert, Christopher T; Mombrikotb, Shorok B; Johnstone, Emma; Barraclough, Timothy G; Bell, Thomas

    2016-09-01

    Bacterial communities are vital for many economically and ecologically important processes. The role of bacterial community composition in determining ecosystem functioning depends critically on interactions among bacterial taxa. Several studies have shown that, despite a predominance of negative interactions in communities, bacteria are able to display positive interactions given the appropriate evolutionary or ecological conditions. We were interested in how interspecific interactions develop over time in a naturalistic setting of low resource supply rates. We assembled aquatic bacterial communities in microcosms and assayed the productivity (respiration and growth) and substrate degradation while tracking community composition. The results demonstrated that while bacterial communities displayed strongly negative interactions during the early phase of colonisation and acclimatisation to novel biotic and abiotic factors, this antagonism declined over time towards a more neutral state. This was associated with a shift from use of labile substrates in early succession to use of recalcitrant substrates later in succession, confirming a crucial role of resource dynamics in linking interspecific interactions with ecosystem functioning.

  16. Ordinary Social Interaction and the Main Effect Between Perceived Support and Affect.

    PubMed

    Lakey, Brian; Vander Molen, Randy J; Fles, Elizabeth; Andrews, Justin

    2016-10-01

    Relational regulation theory hypothesizes that (a) the main effect between perceived support and mental health primarily reflects ordinary social interaction rather than conversations about stress and how to cope with it, and (b) the extent to which a provider regulates a recipient's mental health primarily reflects the recipient's personal taste (i.e., is relational), rather than the provider's objective supportiveness. In three round-robin studies, participants rated each other on supportiveness and the quality of ordinary social interaction, as well as their own affect when interacting with each other. Samples included marines about to deploy to Afghanistan (N = 100; 150 dyads), students sharing apartments (N = 64; 96 dyads), and strangers (N = 48; 72 dyads). Perceived support and ordinary social interaction were primarily relational, and most of perceived support's main effect on positive affect was redundant with ordinary social interaction. The main effect between perceived support and affect emerged among strangers after brief text conversations, and these links were partially verified by independent observers. Findings for negative affect were less consistent with theory. Ordinary social interaction appears to be able to explain much of the main effect between perceived support and positive affect.

  17. Assessing empathy and managing emotions through interactions with an affective avatar.

    PubMed

    Johnson, Esperanza; Hervás, Ramón; Gutiérrez López de la Franca, Carlos; Mondéjar, Tania; Ochoa, Sergio F; Favela, Jesús

    2016-09-30

    Assistive technologies can improve the quality of life of people diagnosed with different forms of social communication disorders. We report on the design and evaluation of an affective avatar aimed at engaging the user in a social interaction with the purpose of assisting in communication therapies. A human-avatar taxonomy is proposed to assist the design of affective avatars aimed at addressing social communication disorder. The avatar was evaluated with 30 subjects to assess how effectively it conveys the desired emotion and elicits empathy from the user. Results provide evidence that users become used to the avatar after a number of interactions, and they perceive the defined behavior as being logical. The users' interactions with the avatar entail affective reactions, including the mimic emotions that users felt, and establish a preliminary ground truth about prototypic empathic interactions with avatars that is being used to train learning algorithms to support social communication disorder evaluation.

  18. Earthworm-mycorrhiza interactions can affect the diversity, structure and functioning of establishing model grassland communities.

    PubMed

    Zaller, Johann G; Heigl, Florian; Grabmaier, Andrea; Lichtenegger, Claudia; Piller, Katja; Allabashi, Roza; Frank, Thomas; Drapela, Thomas

    2011-01-01

    Both earthworms and arbuscular mycorrhizal fungi (AMF) are important ecosystem engineers co-occurring in temperate grasslands. However, their combined impacts during grassland establishment are poorly understood and have never been studied. We used large mesocosms to study the effects of different functional groups of earthworms (i.e., vertically burrowing anecics vs. horizontally burrowing endogeics) and a mix of four AMF taxa on the establishment, diversity and productivity of plant communities after a simulated seed rain of 18 grassland species comprising grasses, non-leguminous forbs and legumes. Moreover, effects of earthworms and/or AMF on water infiltration and leaching of ammonium, nitrate and phosphate were determined after a simulated extreme rainfall event (40 l m(-2)). AMF colonisation of all three plant functional groups was altered by earthworms. Seedling emergence and diversity was reduced by anecic earthworms, however only when AMF were present. Plant density was decreased in AMF-free mesocosms when both anecic and endogeic earthworms were active; with AMF also anecics reduced plant density. Plant shoot and root biomass was only affected by earthworms in AMF-free mesocosms: shoot biomass increased due to the activity of either anecics or endogeics; root biomass increased only when anecics were active. Water infiltration increased when earthworms were present in the mesocosms but remained unaffected by AMF. Ammonium leaching was increased only when anecics or a mixed earthworm community was active but was unaffected by AMF; nitrate and phosphate leaching was neither affected by earthworms nor AMF. Ammonium leaching decreased with increasing plant density, nitrate leaching decreased with increasing plant diversity and density. In order to understand the underlying processes of these interactions further investigations possibly under field conditions using more diverse belowground communities are required. Nevertheless, this study demonstrates that

  19. Browsing affects intra-ring carbon allocation in species with contrasting wood anatomy.

    PubMed

    Palacio, S; Paterson, E; Sim, A; Hester, A J; Millard, P

    2011-02-01

    Current knowledge on tree carbon (C) allocation to wood is particularly scarce in plants subjected to disturbance factors, such as browsing, which affects forest regeneration worldwide and has an impact on the C balance of trees. Furthermore, quantifying the degree to which tree rings are formed from freshly assimilated vs. stored carbohydrates is highly relevant for our understanding of tree C allocation. We used (13)C labelling to quantify seasonal allocation of stored C to wood formation in two species with contrasting wood anatomy: Betula pubescens Ehrh. (diffuse-porous) and Quercus petraea [Matt.] Liebl. (ring-porous). Clipping treatments (66% shoot removal, and unclipped) were applied to analyse the effect of browsing on C allocation into tree rings, plus the effects on tree growth, architecture, ring width and non-structural carbohydrates (NSCs). The relative contribution of stored C to wood formation was greater in the ring-porous (55-70%) than in the diffuse-porous species (35-60%), although each species followed different seasonal trends. Clipping did not cause a significant depletion of C stores in either species. Nonetheless, a significant increase in the proportion of stored C allocated to earlywood growth was observed in clipped birches, and this could be explained through changes in tree architecture after clipping. The size of C pools across tree species seems to be important in determining the variability of seasonal C allocation patterns to wood and their sensibility to disturbances such as browsing. Our results indicate that the observed changes in C allocation to earlywood in birch were not related to variations in the amount or concentration of NSC stores, but to changes in the seasonal availability of recently assimilated C caused by modifications in tree architecture after browsing.

  20. Plant species affect colonization patterns and metabolic activity of associated endophytes during phytoremediation of crude oil-contaminated soil.

    PubMed

    Fatima, K; Imran, A; Amin, I; Khan, Q M; Afzal, M

    2016-04-01

    Plants coupled with endophytic bacteria hold great potential for the remediation of polluted environment. The colonization patterns and activity of inoculated endophytes in rhizosphere and endosphere of host plant are among the primary factors that may influence the phytoremediation process. However, these colonization patterns and metabolic activity of the inoculated endophytes are in turn controlled by none other than the host plant itself. The present study aims to determine such an interaction specifically for plant-endophyte systems remediating crude oil-contaminated soil. A consortium (AP) of two oil-degrading endophytic bacteria (Acinetobacter sp. strain BRSI56 and Pseudomonas aeruginosa strain BRRI54) was inoculated to two grasses, Brachiaria mutica and Leptochloa fusca, vegetated in crude oil-contaminated soil. Colonization patterns and metabolic activity of the endophytes were monitored in the rhizosphere and endosphere of the plants. Bacterial augmentation enhanced plant growth and crude oil degradation. Maximum crude oil degradation (78%) was achieved with B. mutica plants inoculated with AP consortium. This degradation was significantly higher than those treatments, where plants and bacteria were used individually or L. fusca and endophytes were used in combination. Moreover, colonization and metabolic activity of the endophytes were higher in the rhizosphere and endosphere of B. mutica than L. fusca. The plant species affected not only colonization pattern and biofilm formation of the inoculated bacteria in the rhizosphere and endosphere of the host plant but also affected the expression of alkane hydroxylase gene, alkB. Hence, the investigation revealed that plant species can affect colonization patterns and metabolic activity of inoculated endophytic bacteria and ultimately the phytoremediation process.

  1. Indirect interactions among tropical tree species through shared rodent seed predators: a novel mechanism of tree species coexistence.

    PubMed

    Garzon-Lopez, Carol X; Ballesteros-Mejia, Liliana; Ordoñez, Alejandro; Bohlman, Stephanie A; Olff, Han; Jansen, Patrick A

    2015-08-01

    The coexistence of numerous tree species in tropical forests is commonly explained by negative dependence of recruitment on the conspecific seed and tree density due to specialist natural enemies that attack seeds and seedlings ('Janzen-Connell' effects). Less known is whether guilds of shared seed predators can induce a negative dependence of recruitment on the density of different species of the same plant functional group. We studied 54 plots in tropical forest on Barro Colorado Island, Panama, with contrasting mature tree densities of three coexisting large seeded tree species with shared seed predators. Levels of seed predation were far better explained by incorporating seed densities of all three focal species than by conspecific seed density alone. Both positive and negative density dependencies were observed for different species combinations. Thus, indirect interactions via shared seed predators can either promote or reduce the coexistence of different plant functional groups in tropical forest.

  2. An interactive key to the Chrysochromulina species (Haptophyta) described in the literature

    PubMed Central

    Chrétiennot-Dinet, Marie-Josèphe; Desreumaux, Nicolas; Vignes-Lebbe, Régine

    2014-01-01

    Abstract We present a general overview of features and technical specifications of an original interactive key web application for the identification of Chrysochromulina species. The list of species, originally described as belonging in the genus Chrysochromulina, is given and recent taxonomic changes in species and genera of the order Prymnesiales are provided. We briefly discuss the interest of such a key for the identification of phytoplanktonic species. PMID:24596492

  3. Different tree species affect soil respiration spatial distribution in a subtropical forest of southern Taiwan

    NASA Astrophysics Data System (ADS)

    Chiang, Po-Neng; Yu, Jui-Chu; Wang, Ya-nan; Lai, Yen-Jen

    2014-05-01

    Global forests contain 69% of total carbon stored in forest soil and litter. But the carbon storage ability and release rate of warming gases of forest soil also affect global climate change. Soil carbon cycling processes are paid much attention by ecological scientists and policy makers because of the possibility of carbon being stored in soil via land use management. Soil respiration contributed large part of terrestrial carbon flux, but the relationship of soil respiration and climate change was still obscurity. Most of soil respiration researches focus on template and tropical area, little was known that in subtropical area. Afforestation is one of solutions to mitigate CO2 increase and to sequestrate CO2 in tree and soil. Therefore, the objective of this study is to clarify the relationship of tree species and soil respiration distribution in subtropical broad-leaves plantation in southern Taiwan. The research site located on southern Taiwan was sugarcane farm before 2002. The sugarcane was removed and fourteen broadleaved tree species were planted in 2002-2005. Sixteen plots (250m*250m) were set on 1 km2 area, each plot contained 4 subplots (170m2). The forest biomass (i.e. tree height, DBH) understory biomass, litter, and soil C were measured and analyzed at 2011 to 2012. Soil respiration measurement was sampled in each subplot in each month. The soil belongs to Entisol with over 60% of sandstone. The soil pH is 5.5 with low base cations because of high sand percentage. Soil carbon storage showed significantly negative relationship with soil bulk density (p<0.001) in research site. The differences of distribution of live tree C pool among 16 plots were affected by growth characteristic of tree species. Data showed that the accumulation amount of litterfall was highest in December to February and lowest in June. Different tree species planted in 16 plots, resulting in high spatial variation of litterfall amount. It also affected total amount of litterfall

  4. Historical habitat connectivity affects current genetic structure in a grassland species.

    PubMed

    Münzbergová, Z; Cousins, S A O; Herben, T; Plačková, I; Mildén, M; Ehrlén, J

    2013-01-01

    Many recent studies have explored the effects of present and past landscape structure on species distribution and diversity. However, we know little about the effects of past landscape structure on distribution of genetic diversity within and between populations of a single species. Here we describe the relationship between present and past landscape structure (landscape connectivity and habitat size estimated from historical maps) and current genetic structure in a perennial herb, Succisa pratensis. We used allozymes as co-dominant markers to estimate genetic diversity and deviation from Hardy-Weinberg equilibrium in 31 populations distributed within a 5 km(2) agricultural landscape. The results showed that current genetic diversity of populations was related to habitat suitability, habitat age, habitat size and habitat connectivity in the past. The effects of habitat age and past connectivity on genetic diversity were in most cases also significant after taking the current landscape structure into account. Moreover, current genetic similarity between populations was affected by past connectivity after accounting for current landscape structure. In both cases, the oldest time layer (1850) was the most informative. Most populations showed heterozygote excess, indicating disequilibrium due to recent gene flow or selection against homozygotes. These results suggest that habitat age and past connectivity are important determinants of distribution of genetic diversity between populations at a scale of a few kilometres. Landscape history may significantly contribute to our understanding of distribution of current genetic structure within species and the genetic structure may be used to better understand landscape history, even at a small scale.

  5. Traffic noise affects forest bird species in a protected tropical forest.

    PubMed

    Arévalo, J Edgardo; Newhard, Kimberly

    2011-06-01

    have conservation as well as management implications. A decrease in bird species richness and bird abundance due to intrusive road noise could negatively affect the use of trails by visitors. Alternatives for noise attenuation in the affected forest area include the enforcement of speed limits and the planting of live barriers.

  6. Plant compartment and biogeography affect microbiome composition in cultivated and native Agave species.

    PubMed

    Coleman-Derr, Devin; Desgarennes, Damaris; Fonseca-Garcia, Citlali; Gross, Stephen; Clingenpeel, Scott; Woyke, Tanja; North, Gretchen; Visel, Axel; Partida-Martinez, Laila P; Tringe, Susannah G

    2016-01-01

    Desert plants are hypothesized to survive the environmental stress inherent to these regions in part thanks to symbioses with microorganisms, and yet these microbial species, the communities they form, and the forces that influence them are poorly understood. Here we report the first comprehensive investigation of the microbial communities associated with species of Agave, which are native to semiarid and arid regions of Central and North America and are emerging as biofuel feedstocks. We examined prokaryotic and fungal communities in the rhizosphere, phyllosphere, leaf and root endosphere, as well as proximal and distal soil samples from cultivated and native agaves, through Illumina amplicon sequencing. Phylogenetic profiling revealed that the composition of prokaryotic communities was primarily determined by the plant compartment, whereas the composition of fungal communities was mainly influenced by the biogeography of the host species. Cultivated A. tequilana exhibited lower levels of prokaryotic diversity compared with native agaves, although no differences in microbial diversity were found in the endosphere. Agaves shared core prokaryotic and fungal taxa known to promote plant growth and confer tolerance to abiotic stress, which suggests common principles underpinning Agave-microbe interactions.

  7. Macroinvertebrate abundance, water chemistry, and wetland characteristics affect use of wetlands by avian species in Maine

    USGS Publications Warehouse

    Longcore, J.R.; McAuley, D.G.; Pendelton, G.W.; Bennatti, C.R.; Mingo, T.M.; Stromborg, K.L.

    2006-01-01

    Our objective was to determine use by avian species (e.g., piscivores, marsh birds, waterfowl, selected passerines) of 29 wetlands in areas with low (<200 μeq l−1) acid-neutralizing capacity (ANC) in southeastern Maine. We documented bird, pair, and brood use during 1982–1984 and in 1982 we sampled 10 wetlands with a sweep net to collect invertebrates. We related mean numbers of invertebrates per wetland to water chemistry, basin characteristics, and avian use of different wetland types. Shallow, beaver (Castor canadensis)-created wetlands with the highest phosphorus levels and abundant and varied macrophyte assemblages supported greater densities of macroinvertebrates and numbers of duck broods (88.3% of all broods) in contrast to deep, glacial type wetlands with sparse vegetation and lower invertebrate densities that supported fewer broods (11.7%). Low pH may have affected some acid-intolerant invertebrate taxa (i.e., Ephemeroptera), but high mean numbers of Insecta per wetland were recorded from wetlands with a pH of 5.51. Other Classes and Orders of invertebrates were more abundant on wetlands with pH > 5.51. All years combined use of wetlands by broods was greater on wetlands with pH ≤ 5.51 (77.4%) in contract to wetlands with pH > 5.51 that supported 21.8% of the broods. High mean brood density was associated with mean number of Insecta per wetland. For lentic wetlands created by beaver, those habitats contained vegetative structure and nutrients necessary to provide cover to support invertebrate populations that are prey of omnivore and insectivore species. The fishless status of a few wetlands may have affected use by some waterfowl species and obligate piscivores.

  8. Mesoscopic interactions and species coexistence in evolutionary game dynamics of cyclic competitions.

    PubMed

    Cheng, Hongyan; Yao, Nan; Huang, Zi-Gang; Park, Junpyo; Do, Younghae; Lai, Ying-Cheng

    2014-12-15

    Evolutionary dynamical models for cyclic competitions of three species (e.g., rock, paper, and scissors, or RPS) provide a paradigm, at the microscopic level of individual interactions, to address many issues in coexistence and biodiversity. Real ecosystems often involve competitions among more than three species. By extending the RPS game model to five (rock-paper-scissors-lizard-Spock, or RPSLS) mobile species, we uncover a fundamental type of mesoscopic interactions among subgroups of species. In particular, competitions at the microscopic level lead to the emergence of various local groups in different regions of the space, each involving three species. It is the interactions among the groups that fundamentally determine how many species can coexist. In fact, as the mobility is increased from zero, two transitions can occur: one from a five- to a three-species coexistence state and another from the latter to a uniform, single-species state. We develop a mean-field theory to show that, in order to understand the first transition, group interactions at the mesoscopic scale must be taken into account. Our findings suggest, more broadly, the importance of mesoscopic interactions in coexistence of great many species.

  9. Mesoscopic Interactions and Species Coexistence in Evolutionary Game Dynamics of Cyclic Competitions

    PubMed Central

    Cheng, Hongyan; Yao, Nan; Huang, Zi-Gang; Park, Junpyo; Do, Younghae; Lai, Ying-Cheng

    2014-01-01

    Evolutionary dynamical models for cyclic competitions of three species (e.g., rock, paper, and scissors, or RPS) provide a paradigm, at the microscopic level of individual interactions, to address many issues in coexistence and biodiversity. Real ecosystems often involve competitions among more than three species. By extending the RPS game model to five (rock-paper-scissors-lizard-Spock, or RPSLS) mobile species, we uncover a fundamental type of mesoscopic interactions among subgroups of species. In particular, competitions at the microscopic level lead to the emergence of various local groups in different regions of the space, each involving three species. It is the interactions among the groups that fundamentally determine how many species can coexist. In fact, as the mobility is increased from zero, two transitions can occur: one from a five- to a three-species coexistence state and another from the latter to a uniform, single-species state. We develop a mean-field theory to show that, in order to understand the first transition, group interactions at the mesoscopic scale must be taken into account. Our findings suggest, more broadly, the importance of mesoscopic interactions in coexistence of great many species. PMID:25501627

  10. Mesoscopic Interactions and Species Coexistence in Evolutionary Game Dynamics of Cyclic Competitions

    NASA Astrophysics Data System (ADS)

    Cheng, Hongyan; Yao, Nan; Huang, Zi-Gang; Park, Junpyo; Do, Younghae; Lai, Ying-Cheng

    2014-12-01

    Evolutionary dynamical models for cyclic competitions of three species (e.g., rock, paper, and scissors, or RPS) provide a paradigm, at the microscopic level of individual interactions, to address many issues in coexistence and biodiversity. Real ecosystems often involve competitions among more than three species. By extending the RPS game model to five (rock-paper-scissors-lizard-Spock, or RPSLS) mobile species, we uncover a fundamental type of mesoscopic interactions among subgroups of species. In particular, competitions at the microscopic level lead to the emergence of various local groups in different regions of the space, each involving three species. It is the interactions among the groups that fundamentally determine how many species can coexist. In fact, as the mobility is increased from zero, two transitions can occur: one from a five- to a three-species coexistence state and another from the latter to a uniform, single-species state. We develop a mean-field theory to show that, in order to understand the first transition, group interactions at the mesoscopic scale must be taken into account. Our findings suggest, more broadly, the importance of mesoscopic interactions in coexistence of great many species.

  11. Neospora caninum serostatus is affected by age and species variables in cohabiting water buffaloes and beef cattle.

    PubMed

    Moore, D P; Konrad, J L; San Martino, S; Reichel, M P; Cano, D B; Méndez, S; Späth, E J L; Odeón, A C; Crudeli, G; Campero, C M

    2014-07-14

    The aim of this study was to investigate how Neospora caninum serostatus may be affected by variables such as host species (water buffaloes or cattle) and age in animals cohabiting in the same ranch. A convenience cross-sectional study was performed on four ranches in the Northeast of Argentina, where water buffalo are cohabitating with beef cattle. Blood samples were collected from 1350 female water buffaloes (Bubalus bubalis) and 880 female beef cattle (Bos taurus and Bos indicus crossbreeds) from four ranches. Calving and weaning percentages at herd level for each ranch were also recorded. N. caninum antibody levels were measured by an indirect fluorescent antibody test (IFAT) (reciprocal antibody titers ≥ 100). Serological results were classified into 2 categories (0: negative; 1: positive). A logistic regression model was used to describe the relationship between N. caninum serostatus and specie (water buffalo or cattle), age or ranch and their interactions. Likelihood ratio tests were used to assess the significance of the model and their terms. Odds ratios were estimated and 95% profile likelihood (LR) and Wald confidence intervals (CI) obtained. Overall, specific antibody titers were found in 43.3% (584/1350) of water buffaloes and 28.6% (252/880) of cattle. Seropositive water buffaloes and cattle were observed on all ranches. Age was statistically significant (p=0.01) with an overall estimate of logit (log odds) of age of 0.03 for both species. This indicates that for every one year increase in age, the expected change in log odds of being seropositive increased by 0.03. On three of four ranches a water buffalo was 4.48, 1.54 and 2.25 times more likely to be seropositive than cattle for animals of the same age. The N. caninum serostatus was affected by age in the first place, but also by species on at least three of the four ranches. Calving and weaning percentages were higher in water buffaloes than in beef cattle (p<0.05). Even though the low

  12. Predicting the accuracy of facial affect recognition: the interaction of child maltreatment and intellectual functioning.

    PubMed

    Shenk, Chad E; Putnam, Frank W; Noll, Jennie G

    2013-02-01

    Previous research demonstrates that both child maltreatment and intellectual performance contribute uniquely to the accurate identification of facial affect by children and adolescents. The purpose of this study was to extend this research by examining whether child maltreatment affects the accuracy of facial recognition differently at varying levels of intellectual functioning. A sample of maltreated (n=50) and nonmaltreated (n=56) adolescent females, 14 to 19 years of age, was recruited to participate in this study. Participants completed demographic and study-related questionnaires and interviews to control for potential psychological and psychiatric confounds such as symptoms of posttraumatic stress disorder, negative affect, and difficulties in emotion regulation. Participants also completed an experimental paradigm that recorded responses to facial affect displays starting in a neutral expression and changing into a full expression of one of six emotions: happiness, sadness, anger, disgust, fear, or surprise. Hierarchical multiple regression assessed the incremental advantage of evaluating the interaction between child maltreatment and intellectual functioning. Results indicated that the interaction term accounted for a significant amount of additional variance in the accurate identification of facial affect after controlling for relevant covariates and main effects. Specifically, maltreated females with lower levels of intellectual functioning were least accurate in identifying facial affect displays, whereas those with higher levels of intellectual functioning performed as well as nonmaltreated females. These results suggest that maltreatment and intellectual functioning interact to predict the recognition of facial affect, with potential long-term consequences for the interpersonal functioning of maltreated females.

  13. Factors affecting stem borer parasitoid species diversity and parasitism in cultivated and natural habitats.

    PubMed

    Mailafiya, Duna Madu; Le Ru, Bruno Pierre; Kairu, Eunice Waitherero; Calatayud, Paul-André; Dupas, Stéphane

    2010-02-01

    The effects of biotic and abiotic factors on stem borer parasitoid diversity, abundance, and parasitism were studied in cultivated and natural habitats in four agroecological zones in Kenya. Comparing habitat types, we found partial support for the "natural enemy" hypothesis, whereby, across all localities, parasitoid diversity was higher in more diverse host plant communities in natural habitats, whereas parasitoid abundance was higher in cultivated habitats. For both habitats, parasitoid richness was mainly influenced by stem borer density and/or its interaction with stem borer richness, whereas parasitoid abundance was mainly affected by stem borer abundance. Parasitoid richness was higher in localities (with bimodal rainfall distribution) with increased spatial and temporal availability of host plants that harbored the borers. Across seasons, parasitoid richness was lower in both cultivated and natural habitats in the driest locality, Mtito Andei. Overall, parasitoid diversity was low in Suam and Mtito Andei, where maize cultivation was practiced on a commercial scale and intense grazing activities persist across seasons, respectively. Across localities, habitats, and seasons, stem borer parasitism was positively correlated with parasitoid richness and abundance. Furthermore, the interaction of rainfall and altitude influenced the presence and absence of parasitoids, and consequently, stem borer parasitism. Parasitism was positively and negatively correlated with temperature in cultivated and natural habitats, respectively. Overall, natural habitats seem to serve as important refugia for sustaining parasitoid diversity, which in turn can affect stem borer parasitism in the cereal cropping system.

  14. Species richness and interacting factors control invasibility of a marine community

    PubMed Central

    Marraffini, M. L.; Geller, J. B.

    2015-01-01

    Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants, 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies about the role of diversity in regulating invasions reflect uncontrolled variables in those experiments that modified the effect of species richness. Our results suggest that patches of low diversity and abundance may facilitate invasions, and that such patches, once colonized by non-indigenous species, can resist both native and non-indigenous species recruitment. PMID:26203005

  15. Species richness and interacting factors control invasibility of a marine community.

    PubMed

    Marraffini, M L; Geller, J B

    2015-08-07

    Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants, 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies about the role of diversity in regulating invasions reflect uncontrolled variables in those experiments that modified the effect of species richness. Our results suggest that patches of low diversity and abundance may facilitate invasions, and that such patches, once colonized by non-indigenous species, can resist both native and non-indigenous species recruitment.

  16. Knowing your audience affects male-male interactions in Siamese fighting fish (Betta splendens).

    PubMed

    Bertucci, Frédéric; Matos, Ricardo J; Dabelsteen, Torben

    2014-03-01

    Aggressive interactions between animals often occur in the presence of third parties. By observing aggressive signalling interactions, bystanders may eavesdrop and gain relevant information about conspecifics without the costs of interacting. On the other hand, interactants may also adjust their behaviour when an audience is present. This study aimed to test how knowledge about fighting ability of an audience affects aggressive interactions in male Siamese fighting fish. Subjects were positioned between two dyads of non-interacting males and allowed to observe both dyads shortly before the view to one of the dyads was blocked, and the dyads were allowed to interact. Subjects were subsequently exposed to an unknown opponent in the presence of either the winner or the loser of the seen or unseen interaction. The results suggest a complex role of the characteristic of an audience in the agonistic behaviours of a subject engaged in an interaction. The presence of a seen audience elicited more aggressive displays towards the opponent if the audience was a loser. This response was different in the presence of an unseen audience. Subjects then directed a higher aggressiveness against their opponent if the audience was a winner. These results also suggest a potentially more complex and interesting process allowing individuals to gain information about the quality and threat level of an unknown audience while it is interacting with a third party. The importance of information acquisition for an individual to adapt its behaviour and the role of communication networks in shaping social interactions are discussed.

  17. [Novel Hyphenated Techniques of Atomic Spectrometry for Metal Species Interaction with Biomolecules].

    PubMed

    Li, Yan; Yan, Xiu-ping

    2015-09-01

    Trace metals may be adopted by biological systems to assist in the syntheses and metabolic functions of genes (DNA and RNA) and proteins in the environment. These metals may be beneficial or may pose a risk to humans and other life forms. Novel hybrid techniques are required for studies on the interaction between different metal species and biomolecules, which is significant for biology, biochemistry, nutrition, agriculture, medicine, pharmacy, and environmental science. In recent years, our group dwells on new hyphenated techniques based on capillary electrophoresis (CE), electrothermal atomic absorption spectrometry (ETAAS), and inductively coupled plasma mass spectroscopy (ICP-MS), and their application for different metal species interaction with biomolecules such as DNA, HSA, and GSH. The CE-ETAAS assay and CE-ICP-MS assay allow sensitively probing the level of biomolecules such as DNA damage by different metal species and extracting the kinetic and thermodynamic information on the interactions of different metal species with biomolecules, provides direct evidences for the formation of different metal species--biomolecule adducts. In addition, the consequent structural information were extracted from circular dichroism (CD) and X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. The present works represent the most complete and extensive study to date on the interactions between different metal species with biomolecules, and also provide new evidences for and insights into the interactions of different metal species with biomolecules for further understanding of the toxicological effects of metal species.

  18. Moving forward: dispersal and species interactions determine biotic responses to climate change.

    PubMed

    Urban, Mark C; Zarnetske, Phoebe L; Skelly, David K

    2013-09-01

    We need accurate predictions about how climate change will alter species distributions and abundances around the world. Most predictions assume simplistic dispersal scenarios and ignore biotic interactions. We argue for incorporating the complexities of dispersal and species interactions. Range expansions depend not just on mean dispersal, but also on the shape of the dispersal kernel and the population's growth rate. We show how models using species-specific dispersal can produce more accurate predictions than models applying all-or-nothing dispersal scenarios. Models that additionally include species interactions can generate distinct outcomes. For example, species interactions can slow climate tracking and produce more extinctions than models assuming no interactions. We conclude that (1) just knowing mean dispersal is insufficient to predict biotic responses to climate change, and (2) considering interspecific dispersal variation and species interactions jointly will be necessary to anticipate future changes to biological diversity. We advocate for collecting key information on interspecific dispersal differences and strong biotic interactions so that we can build the more robust predictive models that will be necessary to inform conservation efforts as climates continue to change.

  19. Affective Interaction with a Virtual Character Through an fNIRS Brain-Computer Interface.

    PubMed

    Aranyi, Gabor; Pecune, Florian; Charles, Fred; Pelachaud, Catherine; Cavazza, Marc

    2016-01-01

    Affective brain-computer interfaces (BCI) harness Neuroscience knowledge to develop affective interaction from first principles. In this article, we explore affective engagement with a virtual agent through Neurofeedback (NF). We report an experiment where subjects engage with a virtual agent by expressing positive attitudes towards her under a NF paradigm. We use for affective input the asymmetric activity in the dorsolateral prefrontal cortex (DL-PFC), which has been previously found to be related to the high-level affective-motivational dimension of approach/avoidance. The magnitude of left-asymmetric DL-PFC activity, measured using functional near infrared spectroscopy (fNIRS) and treated as a proxy for approach, is mapped onto a control mechanism for the virtual agent's facial expressions, in which action units (AUs) are activated through a neural network. We carried out an experiment with 18 subjects, which demonstrated that subjects are able to successfully engage with the virtual agent by controlling their mental disposition through NF, and that they perceived the agent's responses as realistic and consistent with their projected mental disposition. This interaction paradigm is particularly relevant in the case of affective BCI as it facilitates the volitional activation of specific areas normally not under conscious control. Overall, our contribution reconciles a model of affect derived from brain metabolic data with an ecologically valid, yet computationally controllable, virtual affective communication environment.

  20. Affective Interaction with a Virtual Character Through an fNIRS Brain-Computer Interface

    PubMed Central

    Aranyi, Gabor; Pecune, Florian; Charles, Fred; Pelachaud, Catherine; Cavazza, Marc

    2016-01-01

    Affective brain-computer interfaces (BCI) harness Neuroscience knowledge to develop affective interaction from first principles. In this article, we explore affective engagement with a virtual agent through Neurofeedback (NF). We report an experiment where subjects engage with a virtual agent by expressing positive attitudes towards her under a NF paradigm. We use for affective input the asymmetric activity in the dorsolateral prefrontal cortex (DL-PFC), which has been previously found to be related to the high-level affective-motivational dimension of approach/avoidance. The magnitude of left-asymmetric DL-PFC activity, measured using functional near infrared spectroscopy (fNIRS) and treated as a proxy for approach, is mapped onto a control mechanism for the virtual agent’s facial expressions, in which action units (AUs) are activated through a neural network. We carried out an experiment with 18 subjects, which demonstrated that subjects are able to successfully engage with the virtual agent by controlling their mental disposition through NF, and that they perceived the agent’s responses as realistic and consistent with their projected mental disposition. This interaction paradigm is particularly relevant in the case of affective BCI as it facilitates the volitional activation of specific areas normally not under conscious control. Overall, our contribution reconciles a model of affect derived from brain metabolic data with an ecologically valid, yet computationally controllable, virtual affective communication environment. PMID:27462216

  1. Artificial light pollution: are shifting spectral signatures changing the balance of species interactions?

    PubMed Central

    Davies, Thomas W; Bennie, Jonathan; Inger, Richard; Ibarra, Natalie Hempel; Gaston, Kevin J

    2013-01-01

    Technological developments in municipal lighting are altering the spectral characteristics of artificially lit habitats. Little is yet known of the biological consequences of such changes, although a variety of animal behaviours are dependent on detecting the spectral signature of light reflected from objects. Using previously published wavelengths of peak visual pigment absorbance, we compared how four alternative street lamp technologies affect the visual abilities of 213 species of arachnid, insect, bird, reptile and mammal by producing different wavelength ranges of light to which they are visually sensitive. The proportion of the visually detectable region of the light spectrum emitted by each lamp was compared to provide an indication of how different technologies are likely to facilitate visually guided behaviours such as detecting objects in the environment. Compared to narrow spectrum lamps, broad spectrum technologies enable animals to detect objects that reflect light over more of the spectrum to which they are sensitive and, importantly, create greater disparities in this ability between major taxonomic groups. The introduction of broad spectrum street lamps could therefore alter the balance of species interactions in the artificially lit environment. PMID:23505141

  2. Artificial light pollution: are shifting spectral signatures changing the balance of species interactions?

    PubMed

    Davies, Thomas W; Bennie, Jonathan; Inger, Richard; de Ibarra, Natalie Hempel; Gaston, Kevin J

    2013-05-01

    Technological developments in municipal lighting are altering the spectral characteristics of artificially lit habitats. Little is yet known of the biological consequences of such changes, although a variety of animal behaviours are dependent on detecting the spectral signature of light reflected from objects. Using previously published wavelengths of peak visual pigment absorbance, we compared how four alternative street lamp technologies affect the visual abilities of 213 species of arachnid, insect, bird, reptile and mammal by producing different wavelength ranges of light to which they are visually sensitive. The proportion of the visually detectable region of the light spectrum emitted by each lamp was compared to provide an indication of how different technologies are likely to facilitate visually guided behaviours such as detecting objects in the environment. Compared to narrow spectrum lamps, broad spectrum technologies enable animals to detect objects that reflect light over more of the spectrum to which they are sensitive and, importantly, create greater disparities in this ability between major taxonomic groups. The introduction of broad spectrum street lamps could therefore alter the balance of species interactions in the artificially lit environment.

  3. Comparing photophysiology of seagrasses in the Pacific Northwest: potential implications for species interactions - July 28, 2014

    EPA Science Inventory

    Physiological tolerances are a primary control on species interactions mediated through production and growth. We examined how the physiology of native eelgrass (Zostera marina L.) and introduced Japanese eelgrass (Z. japonica Aschers. & Graeb) responded to temperature in ord...

  4. Comparing photophysiology of seagrasses in the Pacific Northwest: potential implications for species interactions

    EPA Science Inventory

    Physiological tolerances are a primary control on species interactions mediated through production and growth. We examined how the physiology of native eelgrass (Zostera marina L.) and introduced Japanese eelgrass (Z. japonica Aschers. & Graeb) responded to temperature in or...

  5. Species interactions in occurrence data for a community of tick-transmitted pathogens

    PubMed Central

    Estrada-Peña, Agustín; de la Fuente, José

    2016-01-01

    Interactions between tick species, their realized range of hosts, the pathogens they carry and transmit, and the geographic distribution of species in the Western Palearctic were determined based on evidence published between 1970–2014. These relationships were linked to remotely sensed features of temperature and vegetation and used to extract the network of interactions among the organisms. The resulting datasets focused on niche overlap among ticks and hosts, species interactions, and the fraction of the environmental niche in which tick-borne pathogens may circulate as a result of interactions and overlapping environmental traits. The resulting datasets provide a valuable resource for researchers interested in tick-borne pathogens, as they conciliate the abiotic and biotic sides of their niche, allowing exploration of the importance of each host species acting as a vertebrate reservoir in the circulation of tick-transmitted pathogens in the environmental niche. PMID:27479213

  6. Do cave features affect underground habitat exploitation by non-troglobite species?

    NASA Astrophysics Data System (ADS)

    Lunghi, Enrico; Manenti, Raoul; Ficetola, Gentile Francesco

    2014-02-01

    Many biospeleological studies focus on organisms that are exclusive inhabitants of the subterranean realm, but organisms that are not obligate cave-dwellers are frequent in caves, and may account for a substantial portion of biomass. Moreover, several taxa that are usually epigeous are regularly found inside caves, but for most of them it is unknown whether they accidentally enter them, or whether they actively select caves for specific environmental features. In this study we analysed the community of non-strict cave-dwelling organisms (amphibians, gastropods, spiders and orthopterans) in 33 caves from Central Italy, to assess how environmental factors determine community structure. Cave features strongly affected the distribution of the taxa considered. The combined effect of cave morphology and microclimate explained nearly 50% of the variation of community structure. Most of community variation occurred along a gradient from deep, dark and humid caves, to dry caves with wider entrances and extended photic areas. Most of species were associated with humid, deep and dark caves. Most of the non-troglobiont amphibians and invertebrates did not occur randomly in caves, but were associated to caves with specific environmental features. Analysing relationships between cave-dwelling species and environmental variables can allow a more ecological and objective classification of cave-dwelling organisms.

  7. Piper and Vismia species from Colombian Amazonia differentially affect cell proliferation of hepatocarcinoma cells.

    PubMed

    Lizcano, Leandro J; Siles, Maite; Trepiana, Jenifer; Hernández, M Luisa; Navarro, Rosaura; Ruiz-Larrea, M Begoña; Ruiz-Sanz, José Ignacio

    2014-12-30

    There is an increasing interest to identify plant-derived natural products with antitumor activities. In this work, we have studied the effects of aqueous leaf extracts from Amazonian Vismia and Piper species on human hepatocarcinoma cell toxicity. Results showed that, depending on the cell type, the plants displayed differential effects; thus, Vismia baccifera induced the selective killing of HepG2, while increasing cell growth of PLC-PRF and SK-HEP-1. In contrast, these two last cell lines were sensitive to the toxicity by Piper krukoffii and Piper putumayoense, while the Piperaceae did not affect HepG2 growth. All the extracts induced cytotoxicity to rat hepatoma McA-RH7777, but were innocuous (V. baccifera at concentrations < 75 µg/mL) or even protected cells from basal death (P. putumayoense) in primary cultures of rat hepatocytes. In every case, cytotoxicity was accompanied by an intracellular accumulation of reactive oxygen species (ROS). These results provide evidence for the anticancer activities of the studied plants on specific cell lines and suggest that cell killing could be mediated by ROS, thus involving mechanisms independent of the plants free radical scavenging activities. Results also support the use of these extracts of the Vismia and Piper genera with opposite effects as a model system to study the mechanisms of the antitumoral activity against different types of hepatocarcinoma.

  8. Which Factors Affect the Success or Failure of Eradication Campaigns against Alien Species?

    PubMed Central

    Pluess, Therese; Jarošík, Vojtěch; Pyšek, Petr; Cannon, Ray; Pergl, Jan; Breukers, Annemarie; Bacher, Sven

    2012-01-01

    Although issues related to the management of invasive alien species are receiving increasing attention, little is known about which factors affect the likelihood of success of management measures. We applied two data mining techniques, classification trees and boosted trees, to identify factors that relate to the success of management campaigns aimed at eradicating invasive alien invertebrates, plants and plant pathogens. We assembled a dataset of 173 different eradication campaigns against 94 species worldwide, about a half of which (50.9%) were successful. Eradications in man-made habitats, greenhouses in particular, were more likely to succeed than those in (semi-)natural habitats. In man-made habitats the probability of success was generally high in Australasia, while in Europe and the Americas it was higher for local infestations that are easier to deal with, and for international campaigns that are likely to profit from cross-border cooperation. In (semi-) natural habitats, eradication campaigns were more likely to succeed for plants introduced as an ornamental and escaped from cultivation prior to invasion. Averaging out all other factors in boosted trees, pathogens, bacteria and viruses were most, and fungi the least likely to be eradicated; for plants and invertebrates the probability was intermediate. Our analysis indicates that initiating the campaign before the extent of infestation reaches the critical threshold, starting to eradicate within the first four years since the problem has been noticed, paying special attention to species introduced by the cultivation pathway, and applying sanitary measures can substantially increase the probability of eradication success. Our investigations also revealed that information on socioeconomic factors, which are often considered to be crucial for eradication success, is rarely available, and thus their relative importance cannot be evaluated. Future campaigns should carefully document socioeconomic factors to

  9. Which factors affect the success or failure of eradication campaigns against alien species?

    PubMed

    Pluess, Therese; Jarošík, Vojtěch; Pyšek, Petr; Cannon, Ray; Pergl, Jan; Breukers, Annemarie; Bacher, Sven

    2012-01-01

    Although issues related to the management of invasive alien species are receiving increasing attention, little is known about which factors affect the likelihood of success of management measures. We applied two data mining techniques, classification trees and boosted trees, to identify factors that relate to the success of management campaigns aimed at eradicating invasive alien invertebrates, plants and plant pathogens. We assembled a dataset of 173 different eradication campaigns against 94 species worldwide, about a half of which (50.9%) were successful. Eradications in man-made habitats, greenhouses in particular, were more likely to succeed than those in (semi-)natural habitats. In man-made habitats the probability of success was generally high in Australasia, while in Europe and the Americas it was higher for local infestations that are easier to deal with, and for international campaigns that are likely to profit from cross-border cooperation. In (semi-) natural habitats, eradication campaigns were more likely to succeed for plants introduced as an ornamental and escaped from cultivation prior to invasion. Averaging out all other factors in boosted trees, pathogens, bacteria and viruses were most, and fungi the least likely to be eradicated; for plants and invertebrates the probability was intermediate. Our analysis indicates that initiating the campaign before the extent of infestation reaches the critical threshold, starting to eradicate within the first four years since the problem has been noticed, paying special attention to species introduced by the cultivation pathway, and applying sanitary measures can substantially increase the probability of eradication success. Our investigations also revealed that information on socioeconomic factors, which are often considered to be crucial for eradication success, is rarely available, and thus their relative importance cannot be evaluated. Future campaigns should carefully document socioeconomic factors to

  10. Interactions between rates of temperature change and acclimation affect latitudinal patterns of warming tolerance.

    PubMed

    Allen, Jessica L; Chown, Steven L; Janion-Scheepers, Charlene; Clusella-Trullas, Susana

    2016-01-01

    Critical thermal limits form an increasing component of the estimation of impacts of global change on ectotherms. Whether any consistent patterns exist in the interactive effects of rates of temperature change (or experimental ramping rates) and acclimation on critical thermal limits and warming tolerance (one way of assessing sensitivity to climate change) is, however, far from clear. Here, we examine the interacting effects of ramping rate and acclimation on the critical thermal maxima (CTmax) and minima (CTmin) and warming tolerance of six species of springtails from sub-tropical, temperate and polar regions. We also provide microhabitat temperatures from 26 sites spanning 5 years in order to benchmark environmentally relevant rates of temperature change. Ramping rate has larger effects than acclimation on CTmax, but the converse is true for CTmin. Responses to rate and acclimation effects are more consistent among species for CTmax than for CTmin. In the latter case, interactions among ramping rate and acclimation are typical of polar species, less marked for temperate ones, and reduced in species from the sub-tropics. Ramping rate and acclimation have substantial effects on estimates of warming tolerance, with the former being more marked. At the fastest ramping rates (>1.0°C/min), tropical species have estimated warming tolerances similar to their temperate counterparts, whereas at slow ramping rates (<0.4°C/min) the warming tolerance is much reduced in tropical species. Rates of temperate change in microhabitats relevant to the springtails are typically <0.05°C/min, with rare maxima of 0.3-0.5°C/min depending on the site. These findings emphasize the need to consider the environmental setting and experimental conditions when assessing species' vulnerability to climate change using a warming tolerance approach.

  11. Plant Trait Assembly Affects Superiority of Grazer's Foraging Strategies in Species-Rich Grasslands

    PubMed Central

    Mládek, Jan; Mládková, Pavla; Hejcmanová, Pavla; Dvorský, Miroslav; Pavlu, Vilém; De Bello, Francesco; Duchoslav, Martin; Hejcman, Michal; Pakeman, Robin J.

    2013-01-01

    Background Current plant – herbivore interaction models and experiments with mammalian herbivores grazing plant monocultures show the superiority of a maximizing forage quality strategy (MFQ) over a maximizing intake strategy (MI). However, there is a lack of evidence whether grazers comply with the model predictions under field conditions. Methodology/Findings We assessed diet selection of sheep (Ovis aries) using plant functional traits in productive mesic vs. low-productivity dry species-rich grasslands dominated by resource-exploitative vs. resource-conservative species respectively. Each grassland type was studied in two replicates for two years. We investigated the first grazing cycle in a set of 288 plots with a diameter of 30 cm, i.e. the size of sheep feeding station. In mesic grasslands, high plot defoliation was associated with community weighted means of leaf traits referring to high forage quality, i.e. low leaf dry matter content (LDMC) and high specific leaf area (SLA), with a high proportion of legumes and the most with high community weighted mean of forage indicator value. In contrast in dry grasslands, high community weighted mean of canopy height, an estimate of forage quantity, was the best predictor of plot defoliation. Similar differences in selection on forage quality vs. quantity were detected within plots. Sheep selected plants with higher forage indicator values than the plot specific community weighted mean of forage indicator value in mesic grasslands whereas taller plants were selected in dry grasslands. However, at this scale sheep avoided legumes and plants with higher SLA, preferred plants with higher LDMC while grazing plants with higher forage indicator values in mesic grasslands. Conclusions Our findings indicate that MFQ appears superior over MI only in habitats with a predominance of resource-exploitative species. Furthermore, plant functional traits (LDMC, SLA, nitrogen fixer) seem to be helpful correlates of forage quality

  12. Nested species interactions promote feasibility over stability during the assembly of a pollinator community.

    PubMed

    Saavedra, Serguei; Rohr, Rudolf P; Olesen, Jens M; Bascompte, Jordi

    2016-02-01

    The foundational concepts behind the persistence of ecological communities have been based on two ecological properties: dynamical stability and feasibility. The former is typically regarded as the capacity of a community to return to an original equilibrium state after a perturbation in species abundances and is usually linked to the strength of interspecific interactions. The latter is the capacity to sustain positive abundances on all its constituent species and is linked to both interspecific interactions and species demographic characteristics. Over the last 40 years, theoretical research in ecology has emphasized the search for conditions leading to the dynamical stability of ecological communities, while the conditions leading to feasibility have been overlooked. However, thus far, we have no evidence of whether species interactions are more conditioned by the community's need to be stable or feasible. Here, we introduce novel quantitative methods and use empirical data to investigate the consequences of species interactions on the dynamical stability and feasibility of mutualistic communities. First, we demonstrate that the more nested the species interactions in a community are, the lower the mutualistic strength that the community can tolerate without losing dynamical stability. Second, we show that high feasibility in a community can be reached either with high mutualistic strength or with highly nested species interactions. Third, we find that during the assembly process of a seasonal pollinator community located at The Zackenberg Research Station (northeastern Greenland), a high feasibility is reached through the nested species interactions established between newcomer and resident species. Our findings imply that nested mutualistic communities promote feasibility over stability, which may suggest that the former can be key for community persistence.

  13. Interactive effects of emotional and restrained eating on responses to chocolate and affect.

    PubMed

    Macht, Michael; Mueller, Jochen

    2007-12-01

    To examine differences and interactions between emotional and restrained-eating healthy adults (56 women, 53 men) were classified into emotional or restrained eaters, and persons scoring high or low on both dimensions. Participants tasted different types of chocolate (with 30, 70, 85, or 99% cocoa content) and completed questionnaires on affect and attitudes towards chocolate. Emotional eaters reported increased craving for and increased consumption of chocolate, whereas restrained eaters experienced chocolate-related guilt. However, restrained eaters rated plain chocolate (70% and 85% cocoa) as more pleasant than other groups. Persons scoring high on both dimensions showed heightened negative affect and may be prone to disturbances of eating and affect.

  14. Silver nanoparticles affect glucose metabolism in hepatoma cells through production of reactive oxygen species

    PubMed Central

    Lee, Mi Jin; Lee, Seung Jun; Yun, Su Jin; Jang, Ji-Young; Kang, Hangoo; Kim, Kyongmin; Choi, In-Hong; Park, Sun

    2016-01-01

    The silver nanoparticle (AgNP) is a candidate for anticancer therapy because of its effects on cell survival and signaling. Although numerous reports are available regarding their effect on cell death, the effect of AgNPs on metabolism is not well understood. In this study, we investigated the effect of AgNPs on glucose metabolism in hepatoma cell lines. Lactate release from both HepG2 and Huh7 cells was reduced with 5 nm AgNPs as early as 1 hour after treatment, when cell death did not occur. Treatment with 5 nm AgNPs decreased glucose consumption in HepG2 cells but not in Huh7 cells. Treatment with 5 nm AgNPs reduced nuclear factor erythroid 2-like 2 expression in both cell types without affecting its activation at the early time points after AgNPs’ treatment. Increased reactive oxygen species (ROS) production was detected 1 hour after 5 nm AgNPs’ treatment, and lactate release was restored in the presence of an ROS scavenger. Our results suggest that 5 nm AgNPs affect glucose metabolism by producing ROS. PMID:26730190

  15. Silver nanoparticles affect glucose metabolism in hepatoma cells through production of reactive oxygen species.

    PubMed

    Lee, Mi Jin; Lee, Seung Jun; Yun, Su Jin; Jang, Ji-Young; Kang, Hangoo; Kim, Kyongmin; Choi, In-Hong; Park, Sun

    2016-01-01

    The silver nanoparticle (AgNP) is a candidate for anticancer therapy because of its effects on cell survival and signaling. Although numerous reports are available regarding their effect on cell death, the effect of AgNPs on metabolism is not well understood. In this study, we investigated the effect of AgNPs on glucose metabolism in hepatoma cell lines. Lactate release from both HepG2 and Huh7 cells was reduced with 5 nm AgNPs as early as 1 hour after treatment, when cell death did not occur. Treatment with 5 nm AgNPs decreased glucose consumption in HepG2 cells but not in Huh7 cells. Treatment with 5 nm AgNPs reduced nuclear factor erythroid 2-like 2 expression in both cell types without affecting its activation at the early time points after AgNPs' treatment. Increased reactive oxygen species (ROS) production was detected 1 hour after 5 nm AgNPs' treatment, and lactate release was restored in the presence of an ROS scavenger. Our results suggest that 5 nm AgNPs affect glucose metabolism by producing ROS.

  16. Diurnal Human Activity and Introduced Species Affect Occurrence of Carnivores in a Human-Dominated Landscape.

    PubMed

    Moreira-Arce, Dario; Vergara, Pablo M; Boutin, Stan

    2015-01-01

    Diurnal human activity and domestic dogs in agro-forestry mosaics should theoretically modify the diurnal habitat use patterns of native carnivores, with these effects being scale-dependent. We combined intensive camera trapping data with Bayesian occurrence probability models to evaluate both diurnal and nocturnal patterns of space use by carnivores in a mosaic of land-use types in southern Chile. A total of eight carnivores species were recorded, including human-introduced dogs. During the day the most frequently detected species were the culpeo fox and the cougar. Conversely, during the night, the kodkod and chilla fox were the most detected species. The best supported models showed that native carnivores responded differently to landscape attributes and dogs depending on both the time of day as well as the spatial scale of landscape attributes. The positive effect of native forest cover at 250 m and 500 m radius buffers was stronger during the night for the Darwin's fox and cougar. Road density at 250 m scale negatively affected the diurnal occurrence of Darwin´s fox, whereas at 500 m scale roads had a stronger negative effect on the diurnal occurrence of Darwin´s foxes and cougars. A positive effect of road density on dog occurrence was evidenced during both night and day. Patch size had a positive effect on cougar occurrence during night whereas it affected negatively the occurrence of culpeo foxes and skunks during day. Dog occurrence had a negative effect on Darwin's fox occurrence during day-time and night-time, whereas its negative effect on the occurrence of cougar was evidenced only during day-time. Carnivore occurrences were not influenced by the proximity to a conservation area. Our results provided support for the hypothesis that diurnal changes to carnivore occurrence were associated with human and dog activity. Landscape planning in our study area should be focused in reducing both the levels of diurnal human activity in native forest remnants

  17. Diurnal Human Activity and Introduced Species Affect Occurrence of Carnivores in a Human-Dominated Landscape

    PubMed Central

    Moreira-Arce, Dario; Vergara, Pablo M.; Boutin, Stan

    2015-01-01

    Diurnal human activity and domestic dogs in agro-forestry mosaics should theoretically modify the diurnal habitat use patterns of native carnivores, with these effects being scale-dependent. We combined intensive camera trapping data with Bayesian occurrence probability models to evaluate both diurnal and nocturnal patterns of space use by carnivores in a mosaic of land-use types in southern Chile. A total of eight carnivores species were recorded, including human-introduced dogs. During the day the most frequently detected species were the culpeo fox and the cougar. Conversely, during the night, the kodkod and chilla fox were the most detected species. The best supported models showed that native carnivores responded differently to landscape attributes and dogs depending on both the time of day as well as the spatial scale of landscape attributes. The positive effect of native forest cover at 250m and 500 m radius buffers was stronger during the night for the Darwin's fox and cougar. Road density at 250m scale negatively affected the diurnal occurrence of Darwin´s fox, whereas at 500m scale roads had a stronger negative effect on the diurnal occurrence of Darwin´s foxes and cougars. A positive effect of road density on dog occurrence was evidenced during both night and day. Patch size had a positive effect on cougar occurrence during night whereas it affected negatively the occurrence of culpeo foxes and skunks during day. Dog occurrence had a negative effect on Darwin's fox occurrence during day-time and night-time, whereas its negative effect on the occurrence of cougar was evidenced only during day-time. Carnivore occurrences were not influenced by the proximity to a conservation area. Our results provided support for the hypothesis that diurnal changes to carnivore occurrence were associated with human and dog activity. Landscape planning in our study area should be focused in reducing both the levels of diurnal human activity in native forest remnants and

  18. Situational Motivation and Perceived Intensity: Their Interaction in Predicting Changes in Positive Affect from Physical Activity

    PubMed Central

    Guérin, Eva; Fortier, Michelle S.

    2012-01-01

    There is evidence that affective experiences surrounding physical activity can contribute to the proper self-regulation of an active lifestyle. Motivation toward physical activity, as portrayed by self-determination theory, has been linked to positive affect, as has the intensity of physical activity, especially of a preferred nature. The purpose of this experimental study was to examine the interaction between situational motivation and intensity [i.e., ratings of perceived exertion (RPE)] in predicting changes in positive affect following an acute bout of preferred physical activity, namely, running. Fourty-one female runners engaged in a 30-minute self-paced treadmill run in a laboratory context. Situational motivation for running, pre- and post-running positive affect, and RPE were assessed via validated self-report questionnaires. Hierarchical regression analyses revealed a significant interaction effect between RPE and introjection (P < .05) but not between RPE and identified regulation or intrinsic motivation. At low levels of introjection, the influence of RPE on the change in positive affect was considerable, with higher RPE ratings being associated with greater increases in positive affect. The implications of the findings in light of SDT principles as well as the potential contingencies between the regulations and RPE in predicting positive affect among women are discussed. PMID:22778914

  19. PHI-base: a new interface and further additions for the multi-species pathogen-host interactions database.

    PubMed

    Urban, Martin; Cuzick, Alayne; Rutherford, Kim; Irvine, Alistair; Pedro, Helder; Pant, Rashmi; Sadanadan, Vidyendra; Khamari, Lokanath; Billal, Santoshkumar; Mohanty, Sagar; Hammond-Kosack, Kim E

    2017-01-04

    The pathogen-host interactions database (PHI-base) is available at www.phi-base.org PHI-base contains expertly curated molecular and biological information on genes proven to affect the outcome of pathogen-host interactions reported in peer reviewed research articles. In addition, literature that indicates specific gene alterations that did not affect the disease interaction phenotype are curated to provide complete datasets for comparative purposes. Viruses are not included. Here we describe a revised PHI-base Version 4 data platform with improved search, filtering and extended data display functions. A PHIB-BLAST search function is provided and a link to PHI-Canto, a tool for authors to directly curate their own published data into PHI-base. The new release of PHI-base Version 4.2 (October 2016) has an increased data content containing information from 2219 manually curated references. The data provide information on 4460 genes from 264 pathogens tested on 176 hosts in 8046 interactions. Prokaryotic and eukaryotic pathogens are represented in almost equal numbers. Host species belong ∼70% to plants and 30% to other species of medical and/or environmental importance. Additional data types included into PHI-base 4 are the direct targets of pathogen effector proteins in experimental and natural host organisms. The curation problems encountered and the future directions of the PHI-base project are briefly discussed.

  20. PHI-base: a new interface and further additions for the multi-species pathogen–host interactions database

    PubMed Central

    Urban, Martin; Cuzick, Alayne; Rutherford, Kim; Irvine, Alistair; Pedro, Helder; Pant, Rashmi; Sadanadan, Vidyendra; Khamari, Lokanath; Billal, Santoshkumar; Mohanty, Sagar; Hammond-Kosack, Kim E.

    2017-01-01

    The pathogen–host interactions database (PHI-base) is available at www.phi-base.org. PHI-base contains expertly curated molecular and biological information on genes proven to affect the outcome of pathogen–host interactions reported in peer reviewed research articles. In addition, literature that indicates specific gene alterations that did not affect the disease interaction phenotype are curated to provide complete datasets for comparative purposes. Viruses are not included. Here we describe a revised PHI-base Version 4 data platform with improved search, filtering and extended data display functions. A PHIB-BLAST search function is provided and a link to PHI-Canto, a tool for authors to directly curate their own published data into PHI-base. The new release of PHI-base Version 4.2 (October 2016) has an increased data content containing information from 2219 manually curated references. The data provide information on 4460 genes from 264 pathogens tested on 176 hosts in 8046 interactions. Prokaryotic and eukaryotic pathogens are represented in almost equal numbers. Host species belong ∼70% to plants and 30% to other species of medical and/or environmental importance. Additional data types included into PHI-base 4 are the direct targets of pathogen effector proteins in experimental and natural host organisms. The curation problems encountered and the future directions of the PHI-base project are briefly discussed. PMID:27915230

  1. Interactive effects of plant-available soil silicon and herbivory on competition between two grass species

    PubMed Central

    Garbuzov, Mihail; Reidinger, Stefan; Hartley, Susan E.

    2011-01-01

    Background and Aims The herbivore defence system of true grasses (Poaceae) is predominantly based on silicon that is taken up from the soil and deposited in the leaves in the form of abrasive phytoliths. Silicon uptake mechanisms can be both passive and active, with the latter suggesting that there is an energetic cost to silicon uptake. This study assessed the effects of plant-available soil silicon and herbivory on the competitive interactions between the grasses Poa annua, a species that has previously been reported to accumulate only small amounts of silicon, and Lolium perenne, a high silicon accumulator. Methods Plants were grown in mono- and mixed cultures under greenhouse conditions. Plant-available soil silicon levels were manipulated by adding silicon to the soil in the form of sodium silicate. Subsets of mixed culture pots were exposed to above-ground herbivory by desert locusts (Schistocerca gregaria). Key Results In the absence of herbivory, silicon addition increased biomass of P. annua but decreased biomass of L. perenne. Silicon addition increased foliar silicon concentrations of both grass species >4-fold. Under low soil-silicon availability the herbivores removed more leaf biomass from L. perenne than from P. annua, whereas under high silicon availability the reverse was true. Consequently, herbivory shifted the competitive balance between the two grass species, with the outcome depending on the availability of soil silicon. Conclusions It is concluded that a complex interplay between herbivore abundance, growth–defence trade-offs and the availability of soil silicon in the grasses' local environment affects the outcome of inter-specific competition, and so has the potential to impact on plant community structure. PMID:21868406

  2. A new mathematical model of bacterial interactions in two-species oral biofilms.

    PubMed

    Martin, Bénédicte; Tamanai-Shacoori, Zohreh; Bronsard, Julie; Ginguené, Franck; Meuric, Vincent; Mahé, Fabrice; Bonnaure-Mallet, Martine

    2017-01-01

    Periodontitis are bacterial inflammatory diseases, where the bacterial biofilms present on the tooth-supporting tissues switch from a healthy state towards a pathogenic state. Among bacterial species involved in the disease, Porphyromonas gingivalis has been shown to induce dysbiosis, and to induce virulence of otherwise healthy bacteria like Streptococcus gordonii. During biofilm development, primary colonizers such as S. gordonii first attach to the surface and allow the subsequent adhesion of periodontal pathogens such as P. gingivalis. Interactions between those two bacteria have been extensively studied during the adhesion step of the biofilm. The aim of the study was to understand interactions of both species during the growing phase of the biofilm, for which little knowledge is available, using a mathematical model. This two-species biofilm model was based on a substrate-dependent growth, implemented with damage parameters, and validated thanks to data obtained on experimental biofilms. Three different hypothesis of interactions were proposed and assayed using this model: independence, competition between both bacteria species, or induction of toxicity by one species for the other species. Adequacy between experimental and simulated biofilms were found with the last hypothetic mathematical model. This new mathematical model of two species bacteria biofilms, dependent on different substrates for growing, can be applied to any bacteria species, environmental conditions, or steps of biofilm development. It will be of great interest for exploring bacterial interactions in biofilm conditions.

  3. A new mathematical model of bacterial interactions in two-species oral biofilms

    PubMed Central

    Martin, Bénédicte; Tamanai-Shacoori, Zohreh; Bronsard, Julie; Ginguené, Franck; Meuric, Vincent

    2017-01-01

    Periodontitis are bacterial inflammatory diseases, where the bacterial biofilms present on the tooth-supporting tissues switch from a healthy state towards a pathogenic state. Among bacterial species involved in the disease, Porphyromonas gingivalis has been shown to induce dysbiosis, and to induce virulence of otherwise healthy bacteria like Streptococcus gordonii. During biofilm development, primary colonizers such as S. gordonii first attach to the surface and allow the subsequent adhesion of periodontal pathogens such as P. gingivalis. Interactions between those two bacteria have been extensively studied during the adhesion step of the biofilm. The aim of the study was to understand interactions of both species during the growing phase of the biofilm, for which little knowledge is available, using a mathematical model. This two-species biofilm model was based on a substrate-dependent growth, implemented with damage parameters, and validated thanks to data obtained on experimental biofilms. Three different hypothesis of interactions were proposed and assayed using this model: independence, competition between both bacteria species, or induction of toxicity by one species for the other species. Adequacy between experimental and simulated biofilms were found with the last hypothetic mathematical model. This new mathematical model of two species bacteria biofilms, dependent on different substrates for growing, can be applied to any bacteria species, environmental conditions, or steps of biofilm development. It will be of great interest for exploring bacterial interactions in biofilm conditions. PMID:28253369

  4. Inferring species interactions from co-occurrence data with Markov networks.

    PubMed

    Harris, David J

    2016-12-01

    Inferring species interactions from co-occurrence data is one of the most controversial tasks in community ecology. One difficulty is that a single pairwise interaction can ripple through an ecological network and produce surprising indirect consequences. For example, the negative correlation between two competing species can be reversed in the presence of a third species that outcompetes both of them. Here, I apply models from statistical physics, called Markov networks or Markov random fields, that can predict the direct and indirect consequences of any possible species interaction matrix. Interactions in these models can be estimated from observed co-occurrence rates via maximum likelihood, controlling for indirect effects. Using simulated landscapes with known interactions, I evaluated Markov networks and six existing approaches. Markov networks consistently outperformed the other methods, correctly isolating direct interactions between species pairs even when indirect interactions or abiotic factors largely overpowered them. Two computationally efficient approximations, which controlled for indirect effects with partial correlations or generalized linear models, also performed well. Null models showed no evidence of being able to control for indirect effects, and reliably yielded incorrect inferences when such effects were present.

  5. Species interactions and chemical stress: combined effects of intraspecific and interspecific interactions and pyrene on Daphnia magna population dynamics.

    PubMed

    Viaene, Karel P J; De Laender, Frederik; Rico, Andreu; Van den Brink, Paul J; Di Guardo, Antonio; Morselli, Melissa; Janssen, Colin R

    2015-08-01

    Species interactions are often suggested as an important factor when assessing the effects of chemicals on higher levels of biological organization. Nevertheless, the contribution of intraspecific and interspecific interactions to chemical effects on populations is often overlooked. In the present study, Daphnia magna populations were initiated with different levels of intraspecific competition, interspecific competition, and predation and exposed to pyrene pulses. Generalized linear models were used to test which of these factors significantly explained population size and structure at different time points. Pyrene had a negative effect on total population densities, with effects being more pronounced on smaller D. magna individuals. Among all species interactions tested, predation had the largest negative effect on population densities. Predation and high initial intraspecific competition were shown to interact antagonistically with pyrene exposure. This was attributed to differences in population structure before pyrene exposure and pyrene-induced reductions in predation pressure by Chaoborus sp. larvae. The present study provides empirical evidence that species interactions within and between populations can alter the response of aquatic populations to chemical exposure. Therefore, such interactions are important factors to be considered in ecological risk assessments.

  6. Water-triacylglycerol interactions affect oil body structure and seed viability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We are investigating interactions between water and triacylglycerols (TAG) that appear to affect oil body stability and viability of seeds. Dried seeds are usually stored at freezer temperatures (-20oC) for long-term conservation of genetic resources. This globally accepted genebanking practice is...

  7. Interaction between Task Oriented and Affective Information Processing in Cognitive Robotics

    NASA Astrophysics Data System (ADS)

    Haazebroek, Pascal; van Dantzig, Saskia; Hommel, Bernhard

    There is an increasing interest in endowing robots with emotions. Robot control however is still often very task oriented. We present a cognitive architecture that allows the combination of and interaction between task representations and affective information processing. Our model is validated by comparing simulation results with empirical data from experimental psychology.

  8. The Relationship between Affective States and Dialog Patterns during Interactions with AutoTutor

    ERIC Educational Resources Information Center

    Graesser, Arthur C.; D'Mello, Sidney K.; Craig, Scotty D.; Witherspoon, Amy; Sullins, Jeremiah; McDaniel, Bethany; Gholson, Barry

    2008-01-01

    Relations between emotions (affect states) and learning have recently been explored in the context of AutoTutor. AutoTutor is a tutoring system on the Internet that helps learners construct answers to difficult questions by interacting with them in natural language. AutoTutor has an animated conversation agent and a dialog management facility that…

  9. User Experience of Mobile Interactivity: How Do Mobile Websites Affect Attitudes and Relational Outcomes?

    ERIC Educational Resources Information Center

    Dou, Xue

    2013-01-01

    Mobile media offer new opportunities for fostering communications between individuals and companies. Corporate websites are being increasingly accessed via smart phones and companies are scrambling to offer a mobile-friendly user experience on their sites. However, very little is known about how interactivity in the mobile context affects user…

  10. Interspecific interactions between primates, birds, bats, and squirrels may affect community composition on Borneo.

    PubMed

    Beaudrot, Lydia; Struebig, Matthew J; Meijaard, Erik; van Balen, Sebastianus; Husson, Simon; Young, Carson F; Marshall, Andrew J

    2013-02-01

    For several decades, primatologists have been interested in understanding how sympatric primate species are able to coexist. Most of our understanding of primate community ecology derives from the assumption that these animals interact predominantly with other primates. In this study, we investigate to what extent multiple community assembly hypotheses consistent with this assumption are supported when tested with communities of primates in isolation versus with communities of primates, birds, bats, and squirrels together. We focus on vertebrate communities on the island of Borneo, where we examine the determinants of presence or absence of species, and how these communities are structured. We test for checkerboard distributions, guild proportionality, and Fox's assembly rule for favored states, and predict that statistical signals reflecting interactions between ecologically similar species will be stronger when nonprimate taxa are included in analyses. We found strong support for checkerboard distributions in several communities, particularly when taxonomic groups were combined, and after controlling for habitat effects. We found evidence of guild proportionality in some communities, but did not find significant support for Fox's assembly rule in any of the communities examined. These results demonstrate the presence of vertebrate community structure that is ecologically determined rather than randomly generated, which is a finding consistent with the interpretation that interactions within and between these taxonomic groups may have shaped species composition in these communities. This research highlights the importance of considering the broader vertebrate communities with which primates co-occur, and so we urge primatologists to explicitly consider nonprimate taxa in the study of primate ecology.

  11. Dopamine D4 receptor polymorphism and sex interact to predict children’s affective knowledge

    PubMed Central

    Ben-Israel, Sharon; Uzefovsky, Florina; Ebstein, Richard P.; Knafo-Noam, Ariel

    2015-01-01

    Affective knowledge, the ability to understand others’ emotional states, is considered to be a fundamental part in efficient social interaction. Affective knowledge can be seen as related to cognitive empathy, and in the framework of theory of mind (ToM) as affective ToM. Previous studies found that cognitive empathy and ToM are heritable, yet little is known regarding the specific genes involved in individual variability in affective knowledge. Investigating the genetic basis of affective knowledge is important for understanding brain mechanisms underlying socio-cognitive abilities. The 7-repeat (7R) allele within the third exon of the dopamine D4 receptor gene (DRD4-III) has been a focus of interest, due to accumulated knowledge regarding its relevance to individual differences in social behavior. A recent study suggests that an interaction between the DRD4-III polymorphism and sex is associated with cognitive empathy among adults. We aimed to examine the same association in two childhood age groups. Children (N = 280, age 3.5 years, N = 283, age 5 years) participated as part of the Longitudinal Israel Study of Twins. Affective knowledge was assessed through children’s responses to an illustrated story describing different emotional situations, told in a laboratory setting. The findings suggest a significant interaction between sex and the DRD4-III polymorphism, replicated in both age groups. Boy carriers of the 7R allele had higher affective knowledge scores than girls, whereas in the absence of the 7R there was no significant sex effect on affective knowledge. The results support the importance of DRD4-III polymorphism and sex differences to social development. Possible explanations for differences from adult findings are discussed, as are pathways for future studies. PMID:26157401

  12. Toward interactive context-aware affective educational recommendations in computer-assisted language learning

    NASA Astrophysics Data System (ADS)

    Santos, Olga C.; Saneiro, Mar; Boticario, Jesus G.; Rodriguez-Sanchez, M. C.

    2016-01-01

    This work explores the benefits of supporting learners affectively in a context-aware learning situation. This features a new challenge in related literature in terms of providing affective educational recommendations that take advantage of ambient intelligence and are delivered through actuators available in the environment, thus going beyond previous approaches which provided computer-based recommendation that present some text or tell aloud the learner what to do. To address this open issue, we have applied TORMES elicitation methodology, which has been used to investigate the potential of ambient intelligence for making more interactive recommendations in an emotionally challenging scenario (i.e. preparing for the oral examination of a second language learning course). Arduino open source electronics prototyping platform is used both to sense changes in the learners' affective state and to deliver the recommendation in a more interactive way through different complementary sensory communication channels (sight, hearing, touch) to cope with a universal design. An Ambient Intelligence Context-aware Affective Recommender Platform (AICARP) has been built to support the whole experience, which represents a progress in the state of the art. In particular, we have come up with what is most likely the first interactive context-aware affective educational recommendation. The value of this contribution lies in discussing methodological and practical issues involved.

  13. Emotion in languaging: languaging as affective, adaptive, and flexible behavior in social interaction

    PubMed Central

    Jensen, Thomas W.

    2014-01-01

    This article argues for a view on languaging as inherently affective. Informed by recent ecological tendencies within cognitive science and distributed language studies a distinction between first order languaging (language as whole-body sense making) and second order language (language as system like constraints) is put forward. Contrary to common assumptions within linguistics and communication studies separating language-as-a-system from language use (resulting in separations between language vs. body-language and verbal vs. non-verbal communication etc.) the first/second order distinction sees language as emanating from behavior making it possible to view emotion and affect as integral parts languaging behavior. Likewise, emotion and affect are studied, not as inner mental states, but as processes of organism-environment interactions. Based on video recordings of interaction between (1) children with special needs, and (2) couple in therapy and the therapist patterns of reciprocal influences between interactants are examined. Through analyzes of affective stance and patterns of inter-affectivity it is exemplified how language and emotion should not be seen as separate phenomena combined in language use, but rather as completely intertwined phenomena in languaging behavior constrained by second order patterns. PMID:25076921

  14. Evolutionary history and the strength of species interactions: testing the phylogenetic limiting similarity hypothesis.

    PubMed

    Fritschie, Keith J; Cardinale, Bradley J; Alexandrou, Markos A; Oakley, Todd H

    2014-05-01

    A longstanding concept in community ecology is that closely related species compete more strongly than distant relatives. Ecologists have invoked this "limiting similarity hypothesis" to explain patterns in the structure and function of biological communities and to inform conservation, restoration, and invasive-species management. However, few studies have empirically tested the validity of the limiting similarity hypothesis. Here we report the results of a laboratory microcosm experiment in which we used a model system of 23 common, co-occurring North American freshwater green algae to quantify the strength of 216 pairwise species' interactions (the difference in population density when grown alone vs. in the presence of another species) along a manipulated gradient of evolutionary relatedness (phylogenetic distance, as the sum of branch lengths separating species on a molecular phylogeny). Interspecific interactions varied widely in these bicultures of phytoplankton, ranging from strong competition (ratio of relative yield in polyculture vs. monoculture < 1) to moderate facilitation (relative yield > 1). Yet, we found no evidence that the strength of species' interactions was influenced by their evolutionary relatedness. There was no relationship between phylogenetic distance and the average, minimum (inferior competitor), nor maximum (superior competitor) interaction strength across all biculture communities (respectively, P = 0.19, P = 0.17, P = 0.14; N = 428). When we examined each individual species, only 17% of individual species' interactions strengths varied as a function of phylogenetic distance, and none of these relationships remained significant after Bonferoni correction for multiple tests (N = 23). Last, when we grouped interactions into five qualitatively different types, the frequency of these types was not related to phylogenetic distance among species pairs (F4,422 = 1.63, P = 0.15). Our empirical study adds to several others that suggest the

  15. Interactions between rates of temperature change and acclimation affect latitudinal patterns of warming tolerance

    PubMed Central

    Allen, Jessica L.; Chown, Steven L.; Janion-Scheepers, Charlene; Clusella-Trullas, Susana

    2016-01-01

    Critical thermal limits form an increasing component of the estimation of impacts of global change on ectotherms. Whether any consistent patterns exist in the interactive effects of rates of temperature change (or experimental ramping rates) and acclimation on critical thermal limits and warming tolerance (one way of assessing sensitivity to climate change) is, however, far from clear. Here, we examine the interacting effects of ramping rate and acclimation on the critical thermal maxima (CTmax) and minima (CTmin) and warming tolerance of six species of springtails from sub-tropical, temperate and polar regions. We also provide microhabitat temperatures from 26 sites spanning 5 years in order to benchmark environmentally relevant rates of temperature change. Ramping rate has larger effects than acclimation on CTmax, but the converse is true for CTmin. Responses to rate and acclimation effects are more consistent among species for CTmax than for CTmin. In the latter case, interactions among ramping rate and acclimation are typical of polar species, less marked for temperate ones, and reduced in species from the sub-tropics. Ramping rate and acclimation have substantial effects on estimates of warming tolerance, with the former being more marked. At the fastest ramping rates (>1.0°C/min), tropical species have estimated warming tolerances similar to their temperate counterparts, whereas at slow ramping rates (<0.4°C/min) the warming tolerance is much reduced in tropical species. Rates of temperate change in microhabitats relevant to the springtails are typically <0.05°C/min, with rare maxima of 0.3–0.5°C/min depending on the site. These findings emphasize the need to consider the environmental setting and experimental conditions when assessing species’ vulnerability to climate change using a warming tolerance approach. PMID:27933165

  16. Residential mobility, self-concept, and positive affect in social interactions.

    PubMed

    Oishi, Shigehiro; Lun, Janetta; Sherman, Gary D

    2007-07-01

    The present research examined (a) the link between personal history of residential mobility and the self-concept and (b) the implications of such a link for positive affect in social interactions. Study 1 showed that the personal self was more central to the self-definition of frequent movers than to that of nonmovers, whereas the collective self was more central to the self-definition of nonmovers than to that of frequent movers. Results from a laboratory and a 2-week event sampling study (Studies 2 and 3) demonstrated that frequent movers felt happier when an interaction partner accurately perceived their personal selves, whereas nonmovers felt happier when a partner accurately perceived their collective selves. These findings present the first direct evidence on how personal history of residential mobility is linked to important individual differences in the self and positive affect in social interactions.

  17. Plant-pollinator interactions over 120 years: loss of species, co-occurrence, and function.

    PubMed

    Burkle, Laura A; Marlin, John C; Knight, Tiffany M

    2013-03-29

    Using historic data sets, we quantified the degree to which global change over 120 years disrupted plant-pollinator interactions in a temperate forest understory community in Illinois, USA. We found degradation of interaction network structure and function and extirpation of 50% of bee species. Network changes can be attributed to shifts in forb and bee phenologies resulting in temporal mismatches, nonrandom species extinctions, and loss of spatial co-occurrences between extant species in modified landscapes. Quantity and quality of pollination services have declined through time. The historic network showed flexibility in response to disturbance; however, our data suggest that networks will be less resilient to future changes.

  18. Phenological overlap of interacting species in a changing climate: an assessment of available approaches.

    PubMed

    Rafferty, Nicole E; Caradonna, Paul J; Burkle, Laura A; Iler, Amy M; Bronstein, Judith L

    2013-09-01

    Concern regarding the biological effects of climate change has led to a recent surge in research to understand the consequences of phenological change for species interactions. This rapidly expanding research program is centered on three lines of inquiry: (1) how the phenological overlap of interacting species is changing, (2) why the phenological overlap of interacting species is changing, and (3) how the phenological overlap of interacting species will change under future climate scenarios. We synthesize the widely disparate approaches currently being used to investigate these questions: (1) interpretation of long-term phenological data, (2) field observations, (3) experimental manipulations, (4) simulations and nonmechanistic models, and (5) mechanistic models. We present a conceptual framework for selecting approaches that are best matched to the question of interest. We weigh the merits and limitations of each approach, survey the recent literature from diverse systems to quantify their use, and characterize the types of interactions being studied by each of them. We highlight the value of combining approaches and the importance of long-term data for establishing a baseline of phenological synchrony. Future work that scales up from pairwise species interactions to communities and ecosystems, emphasizing the use of predictive approaches, will be particularly valuable for reaching a broader understanding of the complex effects of climate change on the phenological overlap of interacting species. It will also be important to study a broader range of interactions: to date, most of the research on climate-induced phenological shifts has focused on terrestrial pairwise resource-consumer interactions, especially those between plants and insects.

  19. Interactive effects of trait and state affect on top-down control of attention.

    PubMed

    Hur, Juyoen; Miller, Gregory A; McDavitt, Jenika R B; Spielberg, Jeffrey M; Crocker, Laura D; Infantolino, Zachary P; Towers, David N; Warren, Stacie L; Heller, Wendy

    2015-08-01

    Few studies have investigated how attentional control is affected by transient affective states while taking individual differences in affective traits into consideration. In this study, participants completed a color-word Stroop task immediately after undergoing a positive, neutral or negative affective context manipulation (ACM). Behavioral performance was unaffected by any ACM considered in isolation. For individuals high in trait negative affect (NA), performance was impaired by the negative but not the positive or neutral ACM. Neuroimaging results indicate that activity in primarily top-down control regions of the brain (inferior frontal gyrus and dorsal anterior cingulate cortex) was suppressed in the presence of emotional arousal (both negative and positive ACMs). This effect appears to have been exacerbated or offset by co-occurring activity in other top-down control regions (parietal) and emotion processing regions (orbitofrontal cortex, amygdala and nucleus accumbens) as a function of the valence of state affect (positive or negative) and trait affect (trait NA or trait PA). Neuroimaging results are consistent with behavioral findings. In combination, they indicate both additive and interactive influences of trait and state affect on top-down control of attention.

  20. Host-parasite interactions: Marine bivalve molluscs and protozoan parasites, Perkinsus species.

    PubMed

    Soudant, Philippe; E Chu, Fu-Lin; Volety, Aswani

    2013-10-01

    This review assesses and examines the work conducted to date concerning host and parasite interactions between marine bivalve molluscs and protozoan parasites, belonging to Perkinsus species. The review focuses on two well-studied host-parasite interaction models: the two clam species, Ruditapes philippinarum and R. decussatus, and the parasite Perkinsus olseni, and the eastern oyster, Crassostrea virginica, and the parasite Perkinsus marinus. Cellular and humoral defense responses of the host in combating parasitic infection, the mechanisms (e.g., antioxidant enzymes, extracellular products) employed by the parasite in evading host defenses as well as the role of environmental factors in modulating the host-parasite interactions are described.

  1. Honeydew feeding in the solitary bee Osmia bicornis as affected by aphid species and nectar availability.

    PubMed

    Konrad, Roger; Wäckers, Felix L; Romeis, Jörg; Babendreier, Dirk

    2009-12-01

    Like honey bees (Apis mellifera), non-Apis bees could exploit honeydew as a carbohydrate source. In addition to providing carbohydrates, this may expose them to potentially harmful plant products secreted in honeydew. However, knowledge on honeydew feeding by solitary bees is very scarce. Here we determine whether the polylectic solitary bee Osmia bicornis (=O. rufa) collects honeydew under semi-field conditions, and whether this is affected by aphid species and presence of floral nectar. Bees were provided with oilseed rape plants containing flowers and/or colonies of either Myzus persicae or Brevicoryne brassicae. We used the total sugar level of the bee crop as a measure of the individual's nutritional state and the oligosaccharide erlose as indicator for honeydew consumption. Erlose was present in honeydews from both aphid species, while absent in oilseed rape nectar, nor being synthesized by O. bicornis. When bees were confined to a single honeydew type as the only carbohydrate source, consumption of M. persicae honeydew was confirmed for 47% of the bees and consumption of B. brassicae honeydew for only 3%. Increased mortality in the latter treatment provided further evidence that B. brassicae honeydew is an unsuitable food source for O. bicornis. All bees that were given the choice between honeydew and floral nectar showed significantly increased total sugar levels. However, the fact that no erlose was detected in these bees indicates that honeydew was not consumed when suitable floral nectar was available. This study demonstrates that honeydew exploitation by O. bicornis is dependent on honeydew type and the presence of floral nectar.

  2. Dimerization between aequorea fluorescent proteins does not affect interaction between tagged estrogen receptors in living cells.

    PubMed

    Kofoed, Eric M; Guerbadot, Martin; Schaufele, Fred

    2008-01-01

    Forster resonance energy transfer (FRET) detection of protein interaction in living cells is commonly measured following the expression of interacting proteins genetically fused to the cyan (CFP) and yellow (YFP) derivatives of the Aequorea victoria fluorescent protein (FP). These FPs can dimerize at mM concentrations, which may introduce artifacts into the measurement of interaction between proteins that are fused with the FPs. Here, FRET analysis of the interaction between estrogen receptors (alpha isoform, ERalpha) labeled with "wild-type" CFP and YFP is compared with that of ERalpha labeled with "monomeric" A206K mutants of CFP and YFP. The intracellular equilibrium dissociation constant for the hormone-induced ERalpha-ERalpha interaction is similar for ERalpha labeled with wild-type or monomeric FPs. However, the measurement of energy transfer measured for ERalpha-ERalpha interaction in each cell is less consistent with the monomeric FPs. Thus, dimerization of the FPs does not affect the kinetics of ERalpha-ERalpha interaction but, when brought close together via ERalpha-ERalpha interaction, FP dimerization modestly improves FRET measurement.

  3. Selective logging in tropical forests decreases the robustness of liana–tree interaction networks to the loss of host tree species

    PubMed Central

    Magrach, Ainhoa; Senior, Rebecca A.; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F.; Santamaria, Luis; Edwards, David P.

    2016-01-01

    Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the ‘health’ and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana–tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of ‘extinction debt’. PMID:26936241

  4. Selective logging in tropical forests decreases the robustness of liana-tree interaction networks to the loss of host tree species.

    PubMed

    Magrach, Ainhoa; Senior, Rebecca A; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F; Santamaria, Luis; Edwards, David P

    2016-03-16

    Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the 'health' and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana-tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of 'extinction debt'.

  5. Competitive interactions among four pest species of earth mites (Acari: Penthaleidae).

    PubMed

    Umina, P A; Hoffmann, A A

    2005-04-01

    Earth mites are major winter pests of a variety of crops and pastures in southern Australia. Competition between four earth mite species was investigated using field and shadehouse experiments. The influence of different plant hosts on the frequency and intensity of competitive interactions also were examined. This information is important, because control attempts that eradicate one species of mite could be directly followed by an increase in abundance of another earth mite species. There were strong effects of intraspecific competition on the reproductive rate of species, while interspecific interactions between Halotydeus destructor (Tucker) and Penthaleus species and between the three Penthaleus species also were detected. Competitive abilities were altered on the different plant types. On pasture, the competitive advantage swayed between Penthaleus major (Dugés), H. destructor, and Penthaleus falcatus (Qin & Halliday). Penthaleus sp. x was the strongest competitor in a mixture of wheat, Triticum aestivum (L.), and oats, Avena sativa (L.), whereas on canola, Brassica napus (L.), and bristly ox-tongue, Picris echioides (L.), P. falcatus, and H. destructor were superior competitors. These results suggest that competition is a strong force influencing the abundance of earth mites in the field and that host plant factors are important in shaping the type of interactions. This highlights the importance of identifying mite species when considering control options and suggests that effective control recommendations need to be developed for each individual species.

  6. Predicting the process of extinction in experimental microcosms and accounting for interspecific interactions in single-species time series

    PubMed Central

    Ferguson, Jake M; Ponciano, José M

    2014-01-01

    Predicting population extinction risk is a fundamental application of ecological theory to the practice of conservation biology. Here, we compared the prediction performance of a wide array of stochastic, population dynamics models against direct observations of the extinction process from an extensive experimental data set. By varying a series of biological and statistical assumptions in the proposed models, we were able to identify the assumptions that affected predictions about population extinction. We also show how certain autocorrelation structures can emerge due to interspecific interactions, and that accounting for the stochastic effect of these interactions can improve predictions of the extinction process. We conclude that it is possible to account for the stochastic effects of community interactions on extinction when using single-species time series. PMID:24304946

  7. Interaction of Actinide Species with Microorganisms & Microbial Chelators: Cellular Uptake, Toxicity, & Implications for Bioremediation of Soil & Ground Water.

    SciTech Connect

    Hakim Boukhalfa Mary, P. Neu Alvin Crumbliss

    2006-03-28

    Microorganisms influence the natural cycle of major elements, including C, N, P, S, and transition metals such as Mn and Fe. Bacterial processes can also influence the behavior of actinides in soil and ground water. While radionuclides have no known biological utility, they have the potential to interact with microorganisms and to interfere with processes involving other elements such as Fe and Mn. These interactions can transform radionuclides and affect their fate and transport. Organic acids, extruded by-products of cell metabolism, can solubilize radionuclides and facilitate their transport. The soluble complexes formed can be taken up by the cells and incorporated into biofilm structures. We have examined the interactions of Pu species with bacterial metabolites, studied Pu uptake by microorganisms and examined the toxicity of Pu and other toxic metals to environmentally relevant bacteria. We have also studied the speciation of Pu(IV) in the presence of natural and synthetic chelators.

  8. Evolutionary Diversification of Prey and Predator Species Facilitated by Asymmetric Interactions.

    PubMed

    Zu, Jian; Wang, Jinliang; Huang, Gang

    We investigate the influence of asymmetric interactions on coevolutionary dynamics of a predator-prey system by using the theory of adaptive dynamics. We assume that the defense ability of prey and the attack ability of predators all can adaptively evolve, either caused by phenotypic plasticity or by behavioral choice, but there are certain costs in terms of their growth rate or death rate. The coevolutionary model is constructed from a deterministic approximation of random mutation-selection process. To sum up, if prey's trade-off curve is globally weakly concave, then five outcomes of coevolution are demonstrated, which depend on the intensity and shape of asymmetric predator-prey interactions and predator's trade-off shape. Firstly, we find that if there is a weakly decelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species may occur, but after branching further coevolution may lead to extinction of the predator species with a larger trait value. However, if there is a weakly accelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species is also possible and after branching the dimorphic predator can evolutionarily stably coexist with a monomorphic prey species. Secondly, if the asymmetric interactions become a little strong, then prey and predators will evolve to an evolutionarily stable equilibrium, at which they can stably coexist on a long-term timescale of evolution. Thirdly, if there is a weakly accelerating cost and a relatively strongly accelerating benefit for prey species, then evolutionary branching in the prey species is possible and the finally coevolutionary outcome contains a dimorphic prey and a monomorphic predator species. Fourthly, if the asymmetric interactions become more stronger, then predator-prey coevolution may lead to cycles in both traits and equilibrium population densities. The Red Queen dynamic is a

  9. Evolutionary Diversification of Prey and Predator Species Facilitated by Asymmetric Interactions

    PubMed Central

    Zu, Jian; Wang, Jinliang; Huang, Gang

    2016-01-01

    We investigate the influence of asymmetric interactions on coevolutionary dynamics of a predator-prey system by using the theory of adaptive dynamics. We assume that the defense ability of prey and the attack ability of predators all can adaptively evolve, either caused by phenotypic plasticity or by behavioral choice, but there are certain costs in terms of their growth rate or death rate. The coevolutionary model is constructed from a deterministic approximation of random mutation-selection process. To sum up, if prey’s trade-off curve is globally weakly concave, then five outcomes of coevolution are demonstrated, which depend on the intensity and shape of asymmetric predator-prey interactions and predator’s trade-off shape. Firstly, we find that if there is a weakly decelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species may occur, but after branching further coevolution may lead to extinction of the predator species with a larger trait value. However, if there is a weakly accelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species is also possible and after branching the dimorphic predator can evolutionarily stably coexist with a monomorphic prey species. Secondly, if the asymmetric interactions become a little strong, then prey and predators will evolve to an evolutionarily stable equilibrium, at which they can stably coexist on a long-term timescale of evolution. Thirdly, if there is a weakly accelerating cost and a relatively strongly accelerating benefit for prey species, then evolutionary branching in the prey species is possible and the finally coevolutionary outcome contains a dimorphic prey and a monomorphic predator species. Fourthly, if the asymmetric interactions become more stronger, then predator-prey coevolution may lead to cycles in both traits and equilibrium population densities. The Red Queen dynamic is a

  10. A novel non-contact radar sensor for affective and interactive analysis.

    PubMed

    Lin, Hong-Dun; Lee, Yen-Shien; Shih, Hsiang-Lan; Chuang, Bor-Nian

    2013-01-01

    Currently, many physiological signal sensing techniques have been applied for affective analysis in Human-Computer Interaction applications. Most known maturely developed sensing methods (EEG/ECG/EMG/Temperature/BP etc. al.) replied on contact way to obtain desired physiological information for further data analysis. However, those methods might cause some inconvenient and uncomfortable problems, and not easy to be used for affective analysis in interactive performing. To improve this issue, a novel technology based on low power radar technology (Nanosecond Pulse Near-field Sensing, NPNS) with 300 MHz radio-frequency was proposed to detect humans' pulse signal by the non-contact way for heartbeat signal extraction. In this paper, a modified nonlinear HRV calculated algorithm was also developed and applied on analyzing affective status using extracted Peak-to-Peak Interval (PPI) information from detected pulse signal. The proposed new affective analysis method is designed to continuously collect the humans' physiological signal, and validated in a preliminary experiment with sound, light and motion interactive performance. As a result, the mean bias between PPI (from NPNS) and RRI (from ECG) shows less than 1ms, and the correlation is over than 0.88, respectively.

  11. Neural coding of cooperative vs. affective human interactions: 150 ms to code the action's purpose.

    PubMed

    Proverbio, Alice Mado; Riva, Federica; Paganelli, Laura; Cappa, Stefano F; Canessa, Nicola; Perani, Daniela; Zani, Alberto

    2011-01-01

    The timing and neural processing of the understanding of social interactions was investigated by presenting scenes in which 2 people performed cooperative or affective actions. While the role of the human mirror neuron system (MNS) in understanding actions and intentions is widely accepted, little is known about the time course within which these aspects of visual information are automatically extracted. Event-Related Potentials were recorded in 35 university students perceiving 260 pictures of cooperative (e.g., 2 people dragging a box) or affective (e.g., 2 people smiling and holding hands) interactions. The action's goal was automatically discriminated at about 150-170 ms, as reflected by occipito/temporal N170 response. The swLORETA inverse solution revealed the strongest sources in the right posterior cingulate cortex (CC) for affective actions and in the right pSTS for cooperative actions. It was found a right hemispheric asymmetry that involved the fusiform gyrus (BA37), the posterior CC, and the medial frontal gyrus (BA10/11) for the processing of affective interactions, particularly in the 155-175 ms time window. In a later time window (200-250 ms) the processing of cooperative interactions activated the left post-central gyrus (BA3), the left parahippocampal gyrus, the left superior frontal gyrus (BA10), as well as the right premotor cortex (BA6). Women showed a greater response discriminative of the action's goal compared to men at P300 and anterior negativity level (220-500 ms). These findings might be related to a greater responsiveness of the female vs. male MNS. In addition, the discriminative effect was bilateral in women and was smaller and left-sided in men. Evidence was provided that perceptually similar social interactions are discriminated on the basis of the agents' intentions quite early in neural processing, differentially activating regions devoted to face/body/action coding, the limbic system and the MNS.

  12. Ecological consequences of body size decline in harvested fish species: positive feedback loops in trophic interactions amplify human impact.

    PubMed

    Audzijonyte, Asta; Kuparinen, Anna; Gorton, Rebecca; Fulton, Elizabeth A

    2013-04-23

    Humans are changing marine ecosystems worldwide, both directly through fishing and indirectly through climate change. One of the little explored outcomes of human-induced change involves the decreasing body sizes of fishes. We use a marine ecosystem model to explore how a slow (less than 0.1% per year) decrease in the length of five harvested species could affect species interactions, biomasses and yields. We find that even small decreases in fish sizes are amplified by positive feedback loops in the ecosystem and can lead to major changes in natural mortality. For some species, a total of 4 per cent decrease in length-at-age over 50 years resulted in 50 per cent increase in predation mortality. However, the magnitude and direction in predation mortality changes differed among species and one shrinking species even experienced reduced predation pressure. Nevertheless, 50 years of gradual decrease in body size resulted in 1-35% decrease in biomasses and catches of all shrinking species. Therefore, fisheries management practices that ignore contemporary life-history changes are likely to overestimate long-term yields and can lead to overfishing.

  13. Differences in Foliage Affect Performance of the Lappet Moth, Streblote panda: Implications for Species Fitness

    PubMed Central

    Calvo, D.; Molina, J.M.

    2010-01-01

    Implications for adults' fitness through the foliage effects of five different host plants on larval survival and performance of the lappet moth, Streblote panda Hübner (Lepidoptera: Lasiocampidae), as well as their effect on species fitness were assayed. Larvae were reared under controlled laboratory conditions on excised foliage. Long-term developmental experiments were done using first instar larvae to adult emergence, and performance experiments were done using fifth instar larvae. Survival, development rates, and food use were measured. Foliar traits analysis indicated that leaves of different host plants varied, significantly affecting larvae performance and adult fitness. Pistacia lentiscus L. (Sapindales: Anacardiaceae), Arbutus unedo L. (Ericales: Ericaceae), and Retama sphaerocarpa (L.) Boiss. (Fabales: Fabaceae) were the most suitable hosts. Larvae fed on Tamarix gallica L. (Caryophyllales: Tamaricaceae) and Spartium junceum L. (Fabales: Fabaceae) showed the lowest survival, rates of development and pupal and adult weight. In general, S. panda showed a relatively high capacity to buffer low food quality, by reducing developmental rates and larvae development thereby reaching the minimum pupal weight that ensures adult survival. Less suitable plants seem to have indirect effects on adult fitness, producing smaller adults that could disperse to other habitats. PMID:21062148

  14. Elevated tropospheric ozone affects the concentration and allocation of mineral nutrients of two bamboo species.

    PubMed

    Zhuang, Minghao; Lam, Shu Kee; Li, Yingchun; Chen, Shuanglin

    2017-01-15

    The increase in tropospheric ozone (O3) affects plant physiology and ecosystem processes, and consequently the cycle of nutrients. While mineral nutrients are critical for plant growth, the effect of elevated tropospheric O3 concentration on the uptake and allocation of mineral nutrients by plants is not well understood. Using open top chambers (OTCs), we investigated the effect of elevated O3 on calcium (Ca), magnesium (Mg) and iron (Fe) in mature bamboo species Phyllostachys edulis and Oligostachyum lubricum. Our results showed that elevated O3 decreased the leaf biomass of P. edulis and O. lubricum by 35.1% and 26.7%, respectively, but had no significant effect on the biomass of branches, stem or root. For P. edulis, elevated O3 increased the nutrient (Ca, Mg and Fe) concentration and allocation in leaf but reduced the concentration in other organs. In contrast, elevated O3 increased the nutrient concentration and allocation in the branch of O. lubricum but decreased that of other organs. We also found that that P. edulis and O. lubricum responded differently to elevated O3 in terms of nutrient (Ca, Mg and Fe) uptake and allocation. This information is critical for nutrient management and adaptation strategies for sustainable growth of P. edulis and O. lubricum under global climate change.

  15. Estimating abundances of interacting species using morphological traits, foraging guilds, and habitat

    USGS Publications Warehouse

    Dorazio, Robert M.; Connor, Edward F.

    2014-01-01

    We developed a statistical model to estimate the abundances of potentially interacting species encountered while conducting point-count surveys at a set of ecologically relevant locations - as in a metacommunity of species. In the model we assume that abundances of species with similar traits (e.g., body size) are potentially correlated and that these correlations, when present, may exist among all species or only among functionally related species (such as members of the same foraging guild). We also assume that species-specific abundances vary among locations owing to systematic and stochastic sources of heterogeneity. For example, if abundances differ among locations due to differences in habitat, then measures of habitat may be included in the model as covariates. Naturally, the quantitative effects of these covariates are assumed to differ among species. Our model also accounts for the effects of detectability on the observed counts of each species. This aspect of the model is especially important for rare or uncommon species that may be difficult to detect in community-level surveys. Estimating the detectability of each species requires sampling locations to be surveyed repeatedly using different observers or different visits of a single observer. As an illustration, we fitted models to species-specific counts of birds obtained while sampling an avian community during the breeding season. In the analysis we examined whether species abundances appeared to be correlated due to similarities in morphological measures (body mass, beak length, tarsus length, wing length, tail length) and whether these correlations existed among all species or only among species of the same foraging guild. We also used the model to estimate the effects of forested area on species abundances and the effects of sound power output (as measured by body size) on species detection probabilities.

  16. Estimating Abundances of Interacting Species Using Morphological Traits, Foraging Guilds, and Habitat

    PubMed Central

    Dorazio, Robert M.; Connor, Edward F.

    2014-01-01

    We developed a statistical model to estimate the abundances of potentially interacting species encountered while conducting point-count surveys at a set of ecologically relevant locations – as in a metacommunity of species. In the model we assume that abundances of species with similar traits (e.g., body size) are potentially correlated and that these correlations, when present, may exist among all species or only among functionally related species (such as members of the same foraging guild). We also assume that species-specific abundances vary among locations owing to systematic and stochastic sources of heterogeneity. For example, if abundances differ among locations due to differences in habitat, then measures of habitat may be included in the model as covariates. Naturally, the quantitative effects of these covariates are assumed to differ among species. Our model also accounts for the effects of detectability on the observed counts of each species. This aspect of the model is especially important for rare or uncommon species that may be difficult to detect in community-level surveys. Estimating the detectability of each species requires sampling locations to be surveyed repeatedly using different observers or different visits of a single observer. As an illustration, we fitted models to species-specific counts of birds obtained while sampling an avian community during the breeding season. In the analysis we examined whether species abundances appeared to be correlated due to similarities in morphological measures (body mass, beak length, tarsus length, wing length, tail length) and whether these correlations existed among all species or only among species of the same foraging guild. We also used the model to estimate the effects of forested area on species abundances and the effects of sound power output (as measured by body size) on species detection probabilities. PMID:24727898

  17. Risk for Depression and Anxiety in Youth: The Interaction between Negative Affectivity, Effortful Control, and Stressors.

    PubMed

    Gulley, Lauren D; Hankin, Benjamin L; Young, Jami F

    2016-02-01

    Theories of temperament suggest that individual differences in affective reactivity (e.g., negative affectivity) may confer risk for internalizing psychopathology in youth and that self-regulatory aspects of temperament (e.g., effortful control) may protect against the deleterious effects of high negative affective reactivity. However, no study to date has examined how the relationship between temperament and youth internalizing psychopathology may be moderated by stress. The current study used a prospective longitudinal design to test the interaction of temperament (e.g., negative affectivity and effortful control) and stressors as a predictor of youth (ages 7-16; 56 % female; N = 576) depressive and anxious symptoms over a 3-month period. Findings show that at low levels of stress, high levels of effortful control protect against the development of depressive and anxious symptoms among youth with high levels of negative affectivity. However, at high levels of stress, this buffering effect is not observed. Gender and grade did not moderate this relationship. Overall, findings extend current understanding of how the interaction of individual psychosocial vulnerabilities and environmental factors may confer increased or decreased risk for depressive and anxious symptoms.

  18. Risk for Depression and Anxiety in Youth: The Interaction between Negative Affectivity, Effortful Control, and Stressors

    PubMed Central

    Gulley, Lauren D.; Hankin, Benjamin L.; Young, Jami F.

    2015-01-01

    Theories of temperament suggest that individual differences in affective reactivity (e.g., negative affectivity) may confer risk for internalizing psychopathology in youth and that self-regulatory aspects of temperament (e.g., effortful control) may protect against the deleterious effects of high negative affective reactivity. However, no study to date has examined how the relationship between temperament and youth internalizing psychopathology may be moderated by stress. The current study used a prospective longitudinal design to test the interaction of temperament (e.g., negative affectivity and effortful control) and stressors as a predictor of youth (ages 7–16; 56% female; N = 576) depressive and anxious symptoms over a 3-month period. Findings show that at low levels of stress, high levels of effortful control protect against the development of depressive and anxious symptoms among youth with high levels of negative affectivity. However, at high levels of stress, this buffering effect is not observed. Gender and grade did not moderate this relationship. Overall, findings extend current understanding of how the interaction of individual psychosocial vulnerabilities and environmental factors may confer increased or decreased risk for depressive and anxious symptoms. PMID:25870113

  19. Phenotypic and evolutionary consequences of social behaviours: interactions among individuals affect direct genetic effects.

    PubMed

    Trubenová, Barbora; Hager, Reinmar

    2012-01-01

    Traditional quantitative genetics assumes that an individual's phenotype is determined by both genetic and environmental factors. For many animals, part of the environment is social and provided by parents and other interacting partners. When expression of genes in social partners affects trait expression in a focal individual, indirect genetic effects occur. In this study, we explore the effects of indirect genetic effects on the magnitude and range of phenotypic values in a focal individual in a multi-member model analyzing three possible classes of interactions between individuals. We show that social interactions may not only cause indirect genetic effects but can also modify direct genetic effects. Furthermore, we demonstrate that both direct and indirect genetic effects substantially alter the range of phenotypic values, particularly when a focal trait can influence its own expression via interactions with traits in other individuals. We derive a function predicting the relative importance of direct versus indirect genetic effects. Our model reveals that both direct and indirect genetic effects can depend to a large extent on both group size and interaction strength, altering group mean phenotype and variance. This may lead to scenarios where between group variation is much higher than within group variation despite similar underlying genetic properties, potentially affecting the level of selection. Our analysis highlights key properties of indirect genetic effects with important consequences for trait evolution, the level of selection and potentially speciation.

  20. Plant species, atmospheric CO2 and soil N interactively or additively control C allocation within plant-soil systems.

    PubMed

    F U, Shenglei; Ferris, Howard

    2006-12-01

    Two plant species, Medicago truncatula (legume) and Avena sativa (non-legume), were grown in low- or high-N soils under two CO2 concentrations to test the hypothesis whether C allocation within plant-soil system is interactively or additively controlled by soil N and atmospheric CO2 is dependent upon plant species. The results showed the interaction between plant species and soil N had a significant impact on microbial activity and plant growth. The interaction between CO2 and soil N had a significant impact on soil soluble C and soil microbial biomass C under Madicago but not under Avena. Although both CO2 and soil N affected plant growth significantly, there was no interaction between CO2 and soil N on plant growth. In other words, the effects of CO2 and soil N on plant growth were additive. We considered that the interaction between N2 fixation trait of legume plant and elevated CO2 might have obscured the interaction between soil N and elevated CO2 on the growth of legume plant. In low-N soil, the shoot-to-root ratio of Avena dropped from 2.63 +/- 0.20 in the early growth stage to 1.47 +/- 0.03 in the late growth stage, indicating that Avena plant allocated more energy to roots to optimize nutrient uptake (i.e. N) when soil N was limiting. In high-N soil, the shoot-to-root ratio of Medicago increased significantly over time (from 2.45 +/- 0.30 to 5.43 +/- 0.10), suggesting that Medicago plants allocated more energy to shoots to optimize photosynthesis when N was not limiting. The shoot-to-root ratios were not significantly different between two CO2 levels.

  1. Pollinator Behavior Mediates Negative Interactions between Two Congeneric Invasive Plant Species.

    PubMed

    Yang, Suann; Ferrari, Matthew J; Shea, Katriona

    2011-01-01

    Simultaneously flowering plant species may indirectly interact with each other by influencing the quantity of pollinator visitation and/or the quality of pollen that is transferred. These effects on pollination may depend on how pollinators respond to floral resources at multiple levels. In this study, we demonstrate pollinator-mediated negative interactions between two invasive plants, Carduus acanthoides and Carduus nutans. Using constructed arrays of the two species, alone and in mixture, we quantified pollinator visitation at the patch and individual plant levels and measured seed production. We found that co-occurrence of our species led to a shift in pollinator services at both levels. Greater interference occurred when arrays were small and spacings between neighboring plants were large. A spatially explicit movement model suggests that pollinator foraging behavior, which mediates the interactions between plants, was driven by floral display size rather than species identity per se. Pollinator behavior significantly reduced the proportion of seed set for both species relative to that in single-species arrays. Overall, the dependence of pollinator behavior on patch size, spacing between plants, and patch composition can lead to pollinator-mediated plant interactions that range from facilitative to competitive.

  2. Higher-order interaction between molluscs and sheep affecting seedling numbers in grassland

    NASA Astrophysics Data System (ADS)

    Clear Hill, B. H.; Silvertown, J.

    Vertebrate and invertebrate herbivores are both important in mesotrophic grasslands and these two different classes of herbivore potentially interact in their effect upon plant populations. We used two field experiments to test for higher order interactions (HOIs) among sheep, slugs and seedlings, using the mechanistic definition that an HOI occurs when the presence of one species modifies the interaction between two others. In each experiment slug addition and slug-removal treatments were nested inside treatments that altered sheep grazing intensity and timing, and the emergence, of seedlings from experimentally sown seeds was monitored. In Experiment 1, seedling numbers of Cerastium fontanum were increased by intense summer grazing by sheep in both slug-addition and slugremoval treatment, but winter grazing by sheep only increased seedling emergence if slugs were removed. In Experiment 2, winter grazing by sheep significantly reduced total seedling emergence of four species sown ( Lotus corniculatus, Plantago lanceolata, Leucanthemum vulgare, Achillea millefolium), but the effect was only seen where slugs were removed. Though the experimental system is a relatively simple one with only four components (sheep, slugs, seedlings and the matrix vegetation), higher order interactions, a combination of direct and indirect effects and possible switching behaviour by slugs are all suggested by our results.

  3. Rodent-Mediated Interactions Among Seed Species of Differing Quality in a Shrubsteppe Ecosystem

    USGS Publications Warehouse

    Beard, Karen H.; Faulhaber, Craig A.; Howe, Frank P.; Edwards, Thomas C.

    2013-01-01

    Interactions among seeds, mediated by granivorous rodents, are likely to play a strong role in shrubsteppe ecosystem restoration. Past studies typically consider only pairwise interactions between preferred and less preferred seed species, whereas rangeland seedings are likely to contain more than 2 seed species, potentially leading to complex interactions. We examined how the relative proportion of seeds in a 3-species polyculture changes rodent seed selectivity (i.e., removal) and indirect interactions among seeds. We presented 2 rodent species, Peromyscus maniculatus (deer mice) and Perognathus parvus (pocket mice), in arenas with 3-species seed mixtures that varied in the proportion of a highly preferred, moderately preferred, and least preferred seed species, based on preferences determined in this study. We then conducted a field experiment in a pocket mouse—dominated ecosystem with the same 3-species seed mixtures in both “treated” (reduced shrub and increased forb cover) and “untreated” shrubsteppe. In the arena experiment, we found that rodents removed more of the highly preferred seed when the proportions of all 3 seeds were equal. Moderately preferred seeds experienced increased removal when the least preferred seed was in highest proportion. Removal of the least preferred seed increased when the highly preferred seed was in highest proportion. In the field experiment, results were similar to those from the arena experiment and did not differ between treated and untreated shrubsteppe areas. Though our results suggest that 3-species mixtures induce complex interactions among seeds, managers applying these results to restoration efforts should carefully consider the rodent community present and the potential fate of removed seeds.

  4. A new non-indigenous Crassostrea species in Southwest Atlantic salt marshes affects mortality of the cordgrass Spartina alterniflora

    NASA Astrophysics Data System (ADS)

    Lomovasky, Betina J.; Alvarez, Graciela; Addino, Mariana; Montemayor, Diana I.; Iribarne, Oscar

    2014-07-01

    Biological invasions in marine and coastal systems may produce new trophic and nontrophic interactions influencing the structure of the invaded community. In the intertidal salt marshes of Samborombón Bay (36°19‧20″S, 56°46‧26″W; mouth of La Plata River; Argentina), there is a new non-indigenous oyster species, Crassostrea sp., which settles on the dominant smooth cordgrass Spartina alterniflora. Here, we analyzed if the oyster affects S. alterniflora. Sampling showed that density of live plant was similar across intertidal levels, but there were higher density of dead plant stems at low intertidal levels. This pattern coincides with higher density and larger shell size of Crassostrea sp. at the low intertidal where oysters are attached to the basal part of the plant stems. An experiment manipulating oysters attached to S. alterniflora stems and oyster mimics shows that Crassostrea sp. can indeed increase mortality of S. alterniflora. The negative effect of bivalves on plant could be because several oysters settle around the Spartina stem, and by growing during the year, strangle the plants increasing their mortality rate. Together, all these evidences strongly suggest that these non-indigenous oysters can control the lower intertidal level of plant distribution in this system.

  5. Get real: putting models of climate change and species interactions in practice.

    PubMed

    Buckley, Lauren B

    2013-09-01

    Forecasts of the ecological impacts of climate change are generally focused on direct impacts to individual species. Theory and case studies suggest that indirect effects associated with species interactions may alter these direct responses. How can we tractably predict in which cases indirect effects are likely to be important and appropriately model the interaction of abiotic and biotic drivers? One viable strategy is to characterize partitioning between species along thermal, temporal, and spatial niche axes. The partitioning can be informed by assessing functional traits. Mechanistic models can then be applied to predict how climate change will alter niche partitioning. I illustrate this approach by asking whether competition has altered the responses of Caribbean Anolis lizards to recent warming and find that forested habitat has become more suitable for a warm-adapted, open species, and less suitable for a cool-adapted forest inhabitant. Competition may result in competitive displacement of the cool-adapted species as the warm-adapted species moves into the forest. Species interactions may accentuate abundance and distribution shifts predicted in response to climate change along the elevation gradient.

  6. Effects of abiotic factors and species interactions on estimates of male plant function: a meta-analysis.

    PubMed

    Schaeffer, Robert N; Manson, Jessamyn S; Irwin, Rebecca E

    2013-03-01

    The majority of angiosperms are hermaphroditic with total fitness comprised of both male and female components of reproduction. However, most studies examining the effects of abiotic factors and species interactions on fitness have focussed on female reproduction, potentially biasing our understanding of the consequences of environmental factors on total fitness. Here, we use meta-analysis to test how environmental factors affect male function. We obtained 278 effect sizes from 96 studies that measured male function responses to manipulated environmental factors. We found significant effects of abiotic factors and species interactions on estimates of male function, with responses varying depending on environmental factor identity. Male and female responses were correlated for abiotic factor manipulations, but varied based on the type of species interaction (antagonistic or mutualistic). This suggests that measuring only female function may misrepresent whole-plant reproduction depending on context. Finally, we found differences amongst components of male function in response to environmental factors, suggesting that some male function estimates may fail to capture the effects of environmental factors on male fitness. Our results demonstrate the importance of incorporating male function into ecological and evolutionary studies to provide a more accurate understanding of the effects of environmental factors on total fitness.

  7. Accounting for dispersal and biotic interactions to disentangle the drivers of species distributions and their abundances

    PubMed Central

    Boulangeat, Isabelle; Gravel, Dominique; Thuiller, Wilfried

    2014-01-01

    Although abiotic factors, together with dispersal and biotic interactions, are often suggested to explain the distribution of species and their abundances, species distribution models usually focus on abiotic factors only. We propose an integrative framework linking ecological theory, empirical data and statistical models to understand the distribution of species and their abundances together with the underlying community assembly dynamics. We illustrate our approach with 21 plant species in the French Alps. We show that a spatially nested modelling framework significantly improves the model’s performance and that the spatial variations of species presence–absence and abundances are predominantly explained by different factors. We also show that incorporating abiotic, dispersal and biotic factors into the same model bring new insights to our understanding of community assembly. This approach, at the crossroads between community ecology and biogeography, is a promising avenue for a better understanding of species co-existence and biodiversity distribution. PMID:22462813

  8. Interactions among co-infecting parasite species: a mechanism maintaining genetic variation in parasites?

    PubMed

    Seppälä, Otto; Karvonen, Anssi; Valtonen, E Tellervo; Jokela, Jukka

    2009-02-22

    Individuals of free-living organisms are often infected simultaneously by a community of parasites. If the co-infecting parasites interact, then this can add significantly to the diversity of host genotypexparasite genotype interactions. However, interactions between parasite species are usually not examined considering potential variation in interactions between different strain combinations of co-infecting parasites. Here, we examined the importance of interactions between strains of fish eye flukes Diplostomum spathaceum and Diplostomum gasterostei on their infectivity in naive fish hosts. We assessed the infection success of strains of both species in single-strain exposures and in co-exposures with a random strain of the other species. Parasite infection success did not consistently increase or decrease in the co-exposure treatment, but depended on the combinations of co-infecting parasite strains. This disrupted the relative infectivity of D. spathaceum strains observed in single-strain exposures. The infection success of D. gasterostei strains was independent of exposure type. These results suggest that interactions among parasite species may be strain specific and potentially promote maintenance of genetic polymorphism in parasite populations.

  9. Housing conditions and sacrifice protocol affect neural activity and vocal behavior in a songbird species, the zebra finch (Taeniopygia guttata).

    PubMed

    Elie, Julie Estelle; Soula, Hédi Antoine; Trouvé, Colette; Mathevon, Nicolas; Vignal, Clémentine

    2015-12-01

    Individual cages represent a widely used housing condition in laboratories. This isolation represents an impoverished physical and social environment in gregarious animals. It prevents animals from socializing, even when auditory and visual contact is maintained. Zebra finches are colonial songbirds that are widely used as laboratory animals for the study of vocal communication from brain to behavior. In this study, we investigated the effect of single housing on the vocal behavior and the brain activity of male zebra finches (Taeniopygia guttata): male birds housed in individual cages were compared to freely interacting male birds housed as a social group in a communal cage. We focused on the activity of septo-hypothalamic regions of the "social behavior network" (SBN), a set of limbic regions involved in several social behaviors in vertebrates. The activity of four structures of the SBN (BSTm, medial bed nucleus of the stria terminalis; POM, medial preoptic area; lateral septum; ventromedial hypothalamus) and one associated region (paraventricular nucleus of the hypothalamus) was assessed using immunoreactive nuclei density of the immediate early gene Zenk (egr-1). We further assessed the identity of active cell populations by labeling vasotocin (VT). Brain activity was related to behavioral activities of birds like physical and vocal interactions. We showed that individual housing modifies vocal exchanges between birds compared to communal housing. This is of particular importance in the zebra finch, a model species for the study of vocal communication. In addition, a protocol that daily removes one or two birds from the group affects differently male zebra finches depending of their housing conditions: while communally-housed males changed their vocal output, brains of individually housed males show increased Zenk labeling in non-VT cells of the BSTm and enhanced correlation of Zenk-revealed activity between the studied structures. These results show that

  10. How affective information from faces and scenes interacts in the brain.

    PubMed

    Van den Stock, Jan; Vandenbulcke, Mathieu; Sinke, Charlotte B A; Goebel, Rainer; de Gelder, Beatrice

    2014-10-01

    Facial expression perception can be influenced by the natural visual context in which the face is perceived. We performed an fMRI experiment presenting participants with fearful or neutral faces against threatening or neutral background scenes. Triangles and scrambled scenes served as control stimuli. The results showed that the valence of the background influences face selective activity in the right anterior parahippocampal place area (PPA) and subgenual anterior cingulate cortex (sgACC) with higher activation for neutral backgrounds compared to threatening backgrounds (controlled for isolated background effects) and that this effect correlated with trait empathy in the sgACC. In addition, the left fusiform gyrus (FG) responds to the affective congruence between face and background scene. The results show that valence of the background modulates face processing and support the hypothesis that empathic processing in sgACC is inhibited when affective information is present in the background. In addition, the findings reveal a pattern of complex scene perception showing a gradient of functional specialization along the posterior-anterior axis: from sensitivity to the affective content of scenes (extrastriate body area: EBA and posterior PPA), over scene emotion-face emotion interaction (left FG) via category-scene interaction (anterior PPA) to scene-category-personality interaction (sgACC).

  11. Essential oils from clove affect growth of Penicillium species obtained from lemons.

    PubMed

    Martínez, J A; González, R

    2013-01-01

    Continuous use of fungicides to control citrus postharvest diseases has led to increasing resistant strains of pathogens. Since the appearance of fungicide resistance has become an important factor in limiting the efficacy fungicide treatments, new studies have been needed in order to improve control methods. There is a growing consumer's concern about the possible harmful effects of synthetic fungicides on the human health and the environment. Alternatives to synthetic fungicides for citrus decay control include essential oils. These compounds are known for their natural components and they are searched for potential bioactive plant extracts against fungi. In this study, two isolates of P. digitatum and P. italicum each were collected from lemon fruits affected by green and blue mould, respectively. Isolates were purified in potato dextrose agar (PDA) in order to separate the two species which we are demonstrated that they commonly grow together in nature. In vitro assays, in which isolates were grown at 26 degrees C on Petri dishes containing PDA for up to 17 days, were carried out by pouring several doses of essential oils from clove (Syzygium aromaticum L.) on PDA to obtain the following concentrations (v/v): 1.6; 8, 40, 200 and 500 microL L(-1) + tween 80 (0.1 mL L(-1)). Mycelial growth curves and growth, conidiation, mass of aerial mycelium and conidial size were measured. Penicillium isolates showed a slight degree of variability in their growth kinetics, depending on the isolate. 500 microL L(-1) inhibited the growth of all the isolates, whereas concentrations lower than 40 microL L(-1) slightly increased the growth. 200 microL L(-1) reduced both growth and conidiation in all isolates. Aerial mycelium of P. digitatum was not affected by clove, whereas reduced the mass of mycelium of P. italicum at concentrations higher than 8 microL L(-1). In vivo experiment was carried out inoculating a drop of an extract of conidia with a hypodermal syringe though a

  12. Mixed biofilms formed by C. albicans and non-albicans species: a study of microbial interactions.

    PubMed

    Santos, Jéssica Diane dos; Piva, Elisabete; Vilela, Simone Furgeri Godinho; Jorge, Antonio Olavo Cardoso; Junqueira, Juliana Campos

    2016-01-01

    Most Candida infections are related to microbial biofilms often formed by the association of different species. The objective of this study was to evaluate the interactions between Candida albicans and non-albicans species in biofilms formed in vitro. The non-albicans species studied were:Candida tropicalis, Candida glabrata and Candida krusei. Single and mixed biofilms (formed by clinical isolates of C. albicans and non-albicans species) were developed from standardized suspensions of each strain (10(7) cells/mL), on flat-bottom 96-well microtiter plates for 48 hour. These biofilms were analyzed by counting colony-forming units (CFU/mL) in Candida HiChrome agar and by determining cell viability, using the XTT 2,3-bis (2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide colorimetric assay. The results for both the CFU/mL count and the XTT colorimetric assay showed that all the species studied were capable of forming high levels of in vitro biofilm. The number of CFU/mL and the metabolic activity of C. albicans were reduced in mixed biofilms with non-albicans species, as compared with a single C. albicans biofilm. Among the species tested, C. krusei exerted the highest inhibitory action against C. albicans. In conclusion, C. albicans established antagonistic interactions with non-albicans Candida species in mixed biofilms.

  13. Elevated CO2 and plant species diversity interact to slow root decomposition

    SciTech Connect

    De Graaff, Marie-Anne; Schadt, Christopher Warren; Rula, Kelly L; Six, Johan W U A; Schweitzer, Jennifer A; Classen, Aimee T

    2011-01-01

    Changes in plant species diversity can result in synergistic increases in decomposition rates, while elevated atmospheric CO2 can slow the decomposition rates; yet it remains unclear how diversity and changes in atmospheric CO2 may interact to alter root decomposition. To investigate how elevated CO2 interacts with changes in root-litter diversity to alter decomposition rates, we conducted a 120-day laboratory incubation. Roots from three species (Trifolium repens, Lespedeza cuneata, and Festuca pratense) grown under ambient or elevated CO2 were incubated individually or in combination in soils that were exposed to ambient or elevated CO2 for five years. Our experiment resulted in two main findings: (1) Roots from T. repens and L. cuneata, both nitrogen (N) fixers, grown under elevated CO2 treatments had significantly slower decomposition rates than similar roots grown under ambient CO2 treatments; but the decomposition rate of F. pratense roots (a non-N-fixing species) was similar regardless of CO2 treatment. (2) Roots of the three species grown under ambient CO2 and decomposed in combination with each other had faster decomposition rates than when they were decomposed as single species. However, roots of the three species grown under elevated CO2 had similar decomposition rates when they were incubated alone or in combination with other species. These data suggest that if elevated CO2 reduces the root decomposition rate of even a few species in the community, it may slow root decomposition of the entire plant community.

  14. Mechanisms of Disease: Host-Pathogen Interactions between Burkholderia Species and Lung Epithelial Cells

    PubMed Central

    David, Jonathan; Bell, Rachel E.; Clark, Graeme C.

    2015-01-01

    Members of the Burkholderia species can cause a range of severe, often fatal, respiratory diseases. A variety of in vitro models of infection have been developed in an attempt to elucidate the mechanism by which Burkholderia spp. gain entry to and interact with the body. The majority of studies have tended to focus on the interaction of bacteria with phagocytic cells with a paucity of information available with regard to the lung epithelium. However, the lung epithelium is becoming more widely recognized as an important player in innate immunity and the early response to infections. Here we review the complex relationship between Burkholderia species and epithelial cells with an emphasis on the most pathogenic species, Burkholderia pseudomallei and Burkholderia mallei. The current gaps in knowledge in our understanding are highlighted along with the epithelial host-pathogen interactions that offer potential opportunities for therapeutic intervention. PMID:26636042

  15. Database of host-pathogen and related species interactions, and their global distribution.

    PubMed

    Wardeh, Maya; Risley, Claire; McIntyre, Marie Kirsty; Setzkorn, Christian; Baylis, Matthew

    2015-01-01

    Interactions between species, particularly where one is likely to be a pathogen of the other, as well as the geographical distribution of species, have been systematically extracted from various web-based, free-access sources, and assembled with the accompanying evidence into a single database. The database attempts to answer questions such as what are all the pathogens of a host, and what are all the hosts of a pathogen, what are all the countries where a pathogen was found, and what are all the pathogens found in a country. Two datasets were extracted from the database, focussing on species interactions and species distribution, based on evidence published between 1950-2012. The quality of their evidence was checked and verified against well-known, alternative, datasets of pathogens infecting humans, domestic animals and wild mammals. The presented datasets provide a valuable resource for researchers of infectious diseases of humans and animals, including zoonoses.

  16. Database of host-pathogen and related species interactions, and their global distribution

    PubMed Central

    Wardeh, Maya; Risley, Claire; McIntyre, Marie Kirsty; Setzkorn, Christian; Baylis, Matthew

    2015-01-01

    Interactions between species, particularly where one is likely to be a pathogen of the other, as well as the geographical distribution of species, have been systematically extracted from various web-based, free-access sources, and assembled with the accompanying evidence into a single database. The database attempts to answer questions such as what are all the pathogens of a host, and what are all the hosts of a pathogen, what are all the countries where a pathogen was found, and what are all the pathogens found in a country. Two datasets were extracted from the database, focussing on species interactions and species distribution, based on evidence published between 1950–2012. The quality of their evidence was checked and verified against well-known, alternative, datasets of pathogens infecting humans, domestic animals and wild mammals. The presented datasets provide a valuable resource for researchers of infectious diseases of humans and animals, including zoonoses. PMID:26401317

  17. Arabidopsis thaliana polyamine content is modified by the interaction with different Trichoderma species.

    PubMed

    Salazar-Badillo, Fatima Berenice; Sánchez-Rangel, Diana; Becerra-Flora, Alicia; López-Gómez, Miguel; Nieto-Jacobo, Fernanda; Mendoza-Mendoza, Artemio; Jiménez-Bremont, Juan Francisco

    2015-10-01

    Plants are associated with a wide range of microorganisms throughout their life cycle, and some interactions result on plant benefits. Trichoderma species are plant beneficial fungi that enhance plant growth and development, contribute to plant nutrition and induce defense responses. Nevertheless, the molecules involved in these beneficial effects still need to be identify. Polyamines are ubiquitous molecules implicated in plant growth and development, and in the establishment of plant microbe interactions. In this study, we assessed the polyamine profile in Arabidopsis plants during the interaction with Trichoderma virens and Trichoderma atroviride, using a system that allows direct plant-fungal contact or avoids their physical interaction (split system). The plantlets that grew in the split system exhibited higher biomass than the ones in direct contact with Trichoderma species. After 3 days of interaction, a significant decrease in Arabidopsis polyamine levels was observed in both systems (direct contact and split). After 5 days of interaction polyamine levels were increased. The highest levels were observed with T. atroviride (split system), and with T. virens (direct contact). The expression levels of Arabidopsis ADC1 and ADC2 genes during the interaction with the fungi were also assessed. We observed a time dependent regulation of ADC1 and ADC2 genes, which correlates with polyamine levels. Our data show an evident change in polyamine profile during Arabidopsis - Trichoderma interaction, accompanied by evident alterations in plant root architecture. Polyamines could be involved in the changes undergone by plant during the interaction with this beneficial fungus.

  18. The Interactive Effects of Affect Lability, Negative Urgency, and Sensation Seeking on Young Adult Problematic Drinking

    PubMed Central

    Karyadi, Kenny; Coskunpinar, Ayca; Dir, Allyson L.; Cyders, Melissa A.

    2013-01-01

    Prior studies have suggested that affect lability might reduce the risk for problematic drinking among sensation seekers by compensating for their deficiencies in emotional reactivity and among individuals high on negative urgency by disrupting stable negative emotions. Due to the high prevalence of college drinking, this study examined whether affect lability interacted with sensation seeking and negative urgency to influence college student problematic drinking. 414 college drinkers (mean age: 20, 77% female, and 74% Caucasian) from a US Midwestern University completed self-administered questionnaires online. Consistent with our hypotheses, our results indicated that the effects of sensation seeking and negative urgency on problematic drinking weakened at higher levels of affect lability. These findings emphasize the importance of considering specific emotional contexts in understanding how negative urgency and sensation seeking create risk for problematic drinking among college students. These findings might also help us better understand how to reduce problematic drinking among sensation seekers and individuals high on negative urgency. PMID:24826366

  19. Midpoint attractors and species richness: Modelling the interaction between environmental drivers and geometric constraints.

    PubMed

    Colwell, Robert K; Gotelli, Nicholas J; Ashton, Louise A; Beck, Jan; Brehm, Gunnar; Fayle, Tom M; Fiedler, Konrad; Forister, Matthew L; Kessler, Michael; Kitching, Roger L; Klimes, Petr; Kluge, Jürgen; Longino, John T; Maunsell, Sarah C; McCain, Christy M; Moses, Jimmy; Noben, Sarah; Sam, Katerina; Sam, Legi; Shapiro, Arthur M; Wang, Xiangping; Novotny, Vojtech

    2016-09-01

    We introduce a novel framework for conceptualising, quantifying and unifying discordant patterns of species richness along geographical gradients. While not itself explicitly mechanistic, this approach offers a path towards understanding mechanisms. In this study, we focused on the diverse patterns of species richness on mountainsides. We conjectured that elevational range midpoints of species may be drawn towards a single midpoint attractor - a unimodal gradient of environmental favourability. The midpoint attractor interacts with geometric constraints imposed by sea level and the mountaintop to produce taxon-specific patterns of species richness. We developed a Bayesian simulation model to estimate the location and strength of the midpoint attractor from species occurrence data sampled along mountainsides. We also constructed midpoint predictor models to test whether environmental variables could directly account for the observed patterns of species range midpoints. We challenged these models with 16 elevational data sets, comprising 4500 species of insects, vertebrates and plants. The midpoint predictor models generally failed to predict the pattern of species midpoints. In contrast, the midpoint attractor model closely reproduced empirical spatial patterns of species richness and range midpoints. Gradients of environmental favourability, subject to geometric constraints, may parsimoniously account for elevational and other patterns of species richness.

  20. The interaction of borderline personality disorder symptoms and relationship satisfaction in predicting affect.

    PubMed

    Kuhlken, Katherine; Robertson, Christopher; Benson, Jessica; Nelson-Gray, Rosemery

    2014-01-01

    Previous research has suggested that stable, marital relationships may have overall prognostic significance for individuals with borderline personality disorder (BPD); however, research focused on the impact of nonmarital, and perhaps short-term, romantic relationships is lacking. Thus, the primary goal of this study was to examine the impact of the interaction of BPD symptoms and relationship satisfaction on state negative affect in college undergraduates. It was predicted that individuals who scored higher on measures of BPD symptoms and who were in a satisfying romantic relationship would report less negative affect than comparable individuals in a less satisfying romantic relationship. Questionnaires assessing BPD symptoms, relationship satisfaction, and negative affect were administered to 111 women, the majority of whom then completed daily measures of relationship satisfaction and negative affect over a 2-week follow-up period. Hierarchical multiple regression and hierarchical linear modeling were used to test the hypotheses. The interaction of BPD symptoms with relationship satisfaction was found to significantly predict anger, as measured at one time point, suggesting that satisfying romantic relationships may be a protective factor for individuals scoring high on measures of BPD symptoms with regard to anger.

  1. Beyond species recognition: somatic state affects long-distance sex pheromone communication.

    PubMed

    Chemnitz, Johanna; Jentschke, Petra C; Ayasse, Manfred; Steiger, Sandra

    2015-08-07

    Long-range sex pheromones have been subjected to substantial research with a particular focus on their biosynthesis, peripheral perception, central processing and the resulting orientation behaviour of perceivers. Fundamental to the research on sex attractants was the assumption that they primarily coordinate species recognition. However, especially when they are produced by the less limiting sex (usually males), the evolution of heightened condition dependence might be expected and long-range sex pheromones might, therefore, also inform about a signaller's quality. Here we provide, to our knowledge, the first comprehensive study of the role of a male's long-range pheromone in mate choice that combines chemical analyses, video observations and field experiments with a multifactorial manipulation of males' condition. We show that the emission of the long-distance sex pheromone of the burying beetle, Nicrophorus vespilloides is highly condition-dependent and reliably reflects nutritional state, age, body size and parasite load--key components of an individual's somatic state. Both, the quantity and ratio of the pheromone components were affected but the time invested in pheromone emission was largely unaffected by a male's condition. Moreover, the variation in pheromone emission caused by the variation in condition had a strong effect on the attractiveness of males in the field, with males in better nutritional condition, of older age, larger body size and bearing less parasites being more attractive. That a single pheromone is influenced by so many aspects of the somatic state and causes such variation in a male's attractiveness under field conditions was hitherto unknown and highlights the need to integrate indicator models of sexual selection into pheromone research.

  2. Beyond species recognition: somatic state affects long-distance sex pheromone communication

    PubMed Central

    Chemnitz, Johanna; Jentschke, Petra C.; Ayasse, Manfred; Steiger, Sandra

    2015-01-01

    Long-range sex pheromones have been subjected to substantial research with a particular focus on their biosynthesis, peripheral perception, central processing and the resulting orientation behaviour of perceivers. Fundamental to the research on sex attractants was the assumption that they primarily coordinate species recognition. However, especially when they are produced by the less limiting sex (usually males), the evolution of heightened condition dependence might be expected and long-range sex pheromones might, therefore, also inform about a signaller's quality. Here we provide, to our knowledge, the first comprehensive study of the role of a male's long-range pheromone in mate choice that combines chemical analyses, video observations and field experiments with a multifactorial manipulation of males' condition. We show that the emission of the long-distance sex pheromone of the burying beetle, Nicrophorus vespilloides is highly condition-dependent and reliably reflects nutritional state, age, body size and parasite load—key components of an individual's somatic state. Both, the quantity and ratio of the pheromone components were affected but the time invested in pheromone emission was largely unaffected by a male's condition. Moreover, the variation in pheromone emission caused by the variation in condition had a strong effect on the attractiveness of males in the field, with males in better nutritional condition, of older age, larger body size and bearing less parasites being more attractive. That a single pheromone is influenced by so many aspects of the somatic state and causes such variation in a male's attractiveness under field conditions was hitherto unknown and highlights the need to integrate indicator models of sexual selection into pheromone research. PMID:26180067

  3. Heavy metals species affect fungal-bacterial synergism during the bioremediation of fluoranthene.

    PubMed

    Ma, Xiao-Kui; Ding, Ning; Peterson, Eric Charles; Daugulis, Andrew J

    2016-09-01

    The co-occurrence of polycyclic aromatic hydrocarbons (PAHs) with heavy metals (HMs) is very common in contaminated soils, but the influence of HMs on fungal-bacterial synergism during PAH bioremediation has not been investigated. The bioremediation of fluoranthene-contaminated sand using co-cultures of Acremonium sp. P0997 and Bacillus subtilis showed increases of 109.4 and 9.8 % in degradation compared to pure bacterial and fungal cultures, respectively, removing 64.1 ± 1.4 % fluoanthene in total. The presence of Cu(2+) reduced fluoranthene removal to 53.7 ± 1.7 %, while inhibiting bacterial growth, and reducing translocation of bacteria on fungal hyphae by 49.5 %, in terms of the bacterial translocation ratio. Cu(2+) reduced bacterial diffusion by 46.8 and 31.9 %, as reflected by D (a bulk random motility diffusional coefficient) and D eff (the effective one-dimensional diffusion coefficient) compared to the control without HM supplementation, respectively. However, Mn(2+) resulted in a 78.2 ± 1.9 % fluoranthene degradation, representing an increase of 21.9 %, while enhancing bacterial growth and bacterial translocation on fungal hyphae, showing a 12.0 % increase in translocation ratio, with no observable impact on D and D eff. Hence, the presence of HMs has been shown to affect fungal-bacterial synergism in PAH degradation, and this effect differs with HM species.

  4. Non-additive increases in sediment stability are generated by macroinvertebrate species interactions in laboratory streams.

    PubMed

    Albertson, Lindsey K; Cardinale, Bradley J; Sklar, Leonard S

    2014-01-01

    Previous studies have shown that biological structures such as plant roots can have large impacts on landscape morphodynamics, and that physical models that do not incorporate biology can generate qualitatively incorrect predictions of sediment transport. However, work to date has focused almost entirely on the impacts of single, usually dominant, species. Here we ask whether multiple, coexisting species of hydropsychid caddisfly larvae have different impacts on sediment mobility compared to single-species systems due to competitive interactions and niche differences. We manipulated the presence of two common species of net-spinning caddisfly (Ceratopsyche oslari, Arctopsyche californica) in laboratory mesocosms and measured how their silk filtration nets influence the critical shear stress required to initiate sediment grain motion when they were in monoculture versus polyculture. We found that critical shear stress increases non-additively in polycultures where species were allowed to interact. Critical shear stress was 26% higher in multi-species assemblages compared to the average single-species monoculture, and 21% greater than levels of stability achieved by the species having the largest impact on sediment motion in monoculture. Supplementary behavioral experiments suggest the non-additive increase in critical shear stress may have occurred as competition among species led to shifts in the spatial distribution of the two populations and complementary habitat use. To explore the implications of these results for field conditions, we used results from the laboratory study to parameterize a common model of sediment transport. We then used this model to estimate potential bed movement in a natural stream for which we had measurements of channel geometry, grain size, and daily discharge. Although this extrapolation is speculative, it illustrates that multi-species impacts could be sufficiently large to reduce bedload sediment flux over annual time scales in

  5. Non-Additive Increases in Sediment Stability Are Generated by Macroinvertebrate Species Interactions in Laboratory Streams

    PubMed Central

    Albertson, Lindsey K.; Cardinale, Bradley J.; Sklar, Leonard S.

    2014-01-01

    Previous studies have shown that biological structures such as plant roots can have large impacts on landscape morphodynamics, and that physical models that do not incorporate biology can generate qualitatively incorrect predictions of sediment transport. However, work to date has focused almost entirely on the impacts of single, usually dominant, species. Here we ask whether multiple, coexisting species of hydropsychid caddisfly larvae have different impacts on sediment mobility compared to single-species systems due to competitive interactions and niche differences. We manipulated the presence of two common species of net-spinning caddisfly (Ceratopsyche oslari, Arctopsyche californica) in laboratory mesocosms and measured how their silk filtration nets influence the critical shear stress required to initiate sediment grain motion when they were in monoculture versus polyculture. We found that critical shear stress increases non-additively in polycultures where species were allowed to interact. Critical shear stress was 26% higher in multi-species assemblages compared to the average single-species monoculture, and 21% greater than levels of stability achieved by the species having the largest impact on sediment motion in monoculture. Supplementary behavioral experiments suggest the non-additive increase in critical shear stress may have occurred as competition among species led to shifts in the spatial distribution of the two populations and complementary habitat use. To explore the implications of these results for field conditions, we used results from the laboratory study to parameterize a common model of sediment transport. We then used this model to estimate potential bed movement in a natural stream for which we had measurements of channel geometry, grain size, and daily discharge. Although this extrapolation is speculative, it illustrates that multi-species impacts could be sufficiently large to reduce bedload sediment flux over annual time scales in

  6. Does species richness affect fine root biomass and production in young forest plantations?

    PubMed

    Domisch, Timo; Finér, Leena; Dawud, Seid Muhie; Vesterdal, Lars; Raulund-Rasmussen, Karsten

    2015-02-01

    Tree species diversity has been reported to increase forest ecosystem above-ground biomass and productivity, but little is known about below-ground biomass and production in diverse mixed forests compared to single-species forests. For testing whether species richness increases below-ground biomass and production and thus complementarity between forest tree species in young stands, we determined fine root biomass and production of trees and ground vegetation in two experimental plantations representing gradients in tree species richness. Additionally, we measured tree fine root length and determined species composition from fine root biomass samples with the near-infrared reflectance spectroscopy method. We did not observe higher biomass or production in mixed stands compared to monocultures. Neither did we observe any differences in tree root length or fine root turnover. One reason for this could be that these stands were still young, and canopy closure had not always taken place, i.e. a situation where above- or below-ground competition did not yet exist. Another reason could be that the rooting traits of the tree species did not differ sufficiently to support niche differentiation. Our results suggested that functional group identity (i.e. conifers vs. broadleaved species) can be more important for below-ground biomass and production than the species richness itself, as conifers seemed to be more competitive in colonising the soil volume, compared to broadleaved species.

  7. Estimates of Octanol-Water Partitioning for Thousands of Dissolved Organic Species in Oil Sands Process-Affected Water.

    PubMed

    Zhang, Kun; Pereira, Alberto S; Martin, Jonathan W

    2015-07-21

    In this study, the octanol-water distribution ratios (DOW, that is, apparent KOW at pH 8.4) of 2114 organic species in oil sands process-affected water were estimated by partitioning to polydimethylsiloxane (PDMS) coated stir bars and analysis by ultrahigh resolution orbitrap mass spectrometry in electrospray positive ((+)) and negative ((-)) ionization modes. At equilibrium, the majority of species in OSPW showed negligible partitioning to PDMS (i.e., DOW <1), however estimated DOW's for some species ranged up to 100,000. Most organic acids detected in ESI- had negligible partitioning, although some naphthenic acids (O2(-) species) had estimated DOW ranging up to 100. Polar neutral and basic compounds detected in ESI+ generally partitioned to PDMS to a greater extent than organic acids. Among these species, DOW was greatest among 3 groups: up to 1000 for mono-oxygenated species (O(+) species), up to 127,000 for NO(+) species, and up to 203,000 for SO(+) species. A positive relationship was observed between DOW and carbon number, and a negative relationship was observed with the number of double bonds (or rings). The results highlight that nonacidic compounds in OSPW are generally more hydrophobic than naphthenic acids and that some may be highly bioaccumulative and contribute to toxicity.

  8. Interactions between micro- and macroparasites predict microparasite species richness across primates.

    PubMed

    Nunn, Charles L; Brezine, Carrie; Jolles, Anna E; Ezenwa, Vanessa O

    2014-04-01

    Most wild animals face concurrent challenges by multiple infectious organisms, and immunological responses triggered by some parasites may increase susceptibility to other infectious agents. Immune-mediated interactions among parasites have been investigated among individuals in a population, but less is known about broader comparative patterns. We investigated the "macro-micro facilitation hypothesis" that higher helminth prevalence in a host species provides greater opportunities for intracellular parasites to invade, resulting in higher richness of intracellular microparasites. We obtained data on average helminth prevalence for 70 primate hosts, along with data on richness of intra- and extracellular infectious organisms. Using Bayesian phylogenetic methods, we found that primate species with higher overall helminth prevalence harbored more species of intracellular microparasites, while the positive association between helminth prevalence and extracellular microparasite species richness was weaker. The relationships held after controlling for potentially confounding variables, but associations were not found in focused tests of prevalence for six genera of well-studied helminths. The magnitude of support and effect sizes for overall helminth prevalence on intracellular microparasite species richness was similar to support for other well recognized ecological and life-history drivers of parasite species richness. Our findings therefore suggest that intrahost parasite interactions are as important as some ecological characteristics of hosts in accounting for parasite richness across host species.

  9. Big plants — Do they affect neighbourhood species richness and composition in herbaceous vegetation?

    NASA Astrophysics Data System (ADS)

    Aarssen, Lonnie W.; Schamp, Brandon S.; Wight, Stephanie

    2014-02-01

    According to traditional theory, success in competition between plant species generally involves a 'size-advantage'. We predicted therefore that plants with larger body size should impose greater limits on the number of species — especially relatively small ones — that can reside within their immediate neighbourhoods. Species composition was compared within local neighbourhoods surrounding target plants of different sizes belonging to one of the largest herbaceous species found within old-field vegetation in eastern Ontario Canada — Centaurea jacea. Resident species density was generally greater within immediate 'inner' target neighbourhoods than within adjacent circular 'outer' neighbourhoods, and mean body size of resident neighbour species was unrelated to increases in target plant size. As target plant size increased, the proportion of resident neighbour species that were reproductive increased. Relatively big plants of C. jacea do not limit the number or the proportion of reproductive species that can coexist within their immediate neighbourhoods, nor do they cause local exclusion of relatively small species from these neighbourhoods. These results fail to support the 'size-advantage' hypothesis and are more consistent with the 'reproductive economy advantage' hypothesis: success under intense competition is promoted by capacity to recruit offspring that — despite severe suppression — are able to reach their minimum body size needed for reproduction, and hence produce grand-offspring for the next generation. The latter is facilitated by a relatively small minimum reproductive threshold size, which is generally negatively correlated with a relatively large maximum potential body size.

  10. Covariance in species diversity and facilitation among non-interactive parasite taxa: all against the host.

    PubMed

    Krasnov, B R; Mouillot, D; Khokhlova, I S; Shenbrot, G I; Poulin, R

    2005-10-01

    Different parasite taxa exploit different host resources and are often unlikely to interact directly. It is unclear, however, whether the diversity of any given parasite taxon is indirectly influenced by that of other parasite taxa on the same host. Some components of host immune defences may operate simultaneously against all kinds of parasites, whereas investment by the host in specific defences against one type of parasite may come at the expense of defence against other parasites. We investigated the relationships between the species diversity of 4 higher taxa of ectoparasites (fleas, sucking lice, mesostigmatid mites, and ixodid ticks), and between the species richness of ectoparasites and endoparasitic helminths, across different species of rodent hosts. Our analyses used 2 measures of species diversity, species richness and taxonomic distinctness, and controlled for the potentially confounding effects of sampling effort and phylogenetic relationships among host species. We found positive pairwise correlations between the species richness of fleas, mites and ticks; however, there was no association between species richness of any of these 3 groups and that of lice. We also found a strong positive relationship between the taxonomic distinctness of ecto- and endoparasite assemblages across host species. These results suggest the existence of a process of apparent facilitation among unrelated taxa in the organization of parasite communities. We propose explanations based on host immune responses, involving acquired cross-resistance to infection and interspecific variation in immunocompetence among hosts, to account for these patterns.

  11. [Ecosystem service interactions and their affecting factors in Jinghe watershed at county level].

    PubMed

    Pan, Ying; Zhen, Lin; Long, Xin; Cao, Xiao-Chang

    2012-05-01

    Taking the multiple ecosystem services (grain supply, meat supply, fuel-wood supply, water resource conservation and soil retention) as test objects, this paper analyzed the interactions among these services, the interaction modes and the possible affecting factors in 31 counties of Jinghe watershed. At the county level, there existed great differences in the interactions among different pairs of the ecosystem services. The grain supply showed significant positive correlation with meat supply but negative correlation with soil retention, whereas the water resource conservation showed significant positive correlations with fuel-wood supply and soil retention. As for the interaction modes of the ecosystem services, 24 counties were primarily of regulation services, 3 counties were of supply and regulation services in balance, and 4 counties were primarily of grain supply. The total ecosystem service index of the interaction modes in each county varied greatly, with 5.1 times of difference between the maximum (Jingyuan County) and the minimum value (Yanchi County). The total ecosystem service index was significantly positively correlated with precipitation and soil total nitrogen, and negatively correlated with solar hours. The increase of farmland had negative effects, while that of shrub land and grassland had great positive effects on the total ecosystem service index, but the increase of forestland had less effects.

  12. Biotic Interactions Overrule Plant Responses to Climate, Depending on the Species' Biogeography

    PubMed Central

    Welk, Astrid; Welk, Erik; Bruelheide, Helge

    2014-01-01

    This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type) responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account. PMID:25356912

  13. Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

    PubMed

    Welk, Astrid; Welk, Erik; Bruelheide, Helge

    2014-01-01

    This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type) responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account.

  14. Interactions between terrestrial mammals and the fruits of two neotropical rainforest tree species

    NASA Astrophysics Data System (ADS)

    Camargo-Sanabria, Angela A.; Mendoza, Eduardo

    2016-05-01

    Mammalian frugivory is a distinctive biotic interaction of tropical forests; however, most efforts in the Neotropics have focused on cases of animals foraging in the forest canopy, in particular primates and bats. In contrast much less is known about this interaction when it involves fruits deposited on the forest floor and terrestrial mammals. We conducted a camera-trapping survey to analyze the characteristics of the mammalian ensembles visiting fruits of Licania platypus and Pouteria sapota deposited on the forest floor in a well preserved tropical rainforest of Mexico. Both tree species produce large fruits but contrast in their population densities and fruit chemical composition. In particular, we expected that more species of terrestrial mammals would consume P. sapota fruits due to its higher pulp:seed ratio, lower availability and greater carbohydrate content. We monitored fruits at the base of 13 trees (P. sapota, n = 4 and L. platypus, n = 9) using camera-traps. We recorded 13 mammal species from which we had evidence of 8 consuming or removing fruits. These eight species accounted for 70% of the species of mammalian frugivores active in the forest floor of our study area. The ensemble of frugivores associated with L. platypus (6 spp.) was a subset of that associated with P. sapota (8 spp). Large body-sized species such as Tapirus bairdii, Pecari tajacu and Cuniculus paca were the mammals more frequently interacting with fruits of the focal species. Our results further our understanding of the characteristics of the interaction between terrestrial mammalian frugivores and large-sized fruits, helping to gain a more balanced view of its importance across different tropical forests and providing a baseline to compare against defaunated forests.

  15. Sorption interactions of organic compounds with soils affected by agricultural olive mill wastewater.

    PubMed

    Keren, Yonatan; Borisover, Mikhail; Bukhanovsky, Nadezhda

    2015-11-01

    The organic compound-soil interactions may be strongly influenced by changes in soil organic matter (OM) which affects the environmental fate of multiple organic pollutants. The soil OM changes may be caused by land disposal of various OM-containing wastes. One unique type of OM-rich waste is olive mill-related wastewater (OMW) characterized by high levels of OM, the presence of fatty aliphatics and polyphenolic aromatics. The systematic data on effects of the land-applied OMW on organic compound-soil interactions is lacking. Therefore, aqueous sorption of simazine and diuron, two herbicides, was examined in batch experiments onto three soils, including untreated and OMW-affected samples. Typically, the organic compound-soil interactions increased following the prior land application of OMW. This increase is associated with the changes in sorption mechanisms and cannot be attributed solely to the increase in soil organic carbon content. A novel observation is that the OMW application changes the soil-sorbent matrix in such a way that the solute uptake may become cooperative or the existing ability of a soil sorbent to cooperatively sorb organic molecules from water may become characterized by a larger affinity. The remarkable finding of this study was that in some cases a cooperative uptake of organic molecules by soils makes itself evident in distinct sigmoidal sorption isotherms rarely observed in soil sorption of non-ionized organic compounds; the cooperative herbicide-soil interactions may be characterized by the Hill model coefficients. However, no single trend was found for the effect of applied OMW on the mechanisms of organic compound-soil interactions.

  16. Motion and emotion: depression reduces psychomotor performance and alters affective movements in caregiving interactions

    PubMed Central

    Young, Katherine S.; Parsons, Christine E.; Stein, Alan; Kringelbach, Morten L.

    2015-01-01

    Background: Impaired social functioning is a well-established feature of depression. Evidence to date suggests that disrupted processing of emotional cues may constitute part of this impairment. Beyond processing of emotional cues, fluent social interactions require that people physically move in synchronized, contingent ways. Disruptions to physical movements are a diagnostic feature of depression (psychomotor disturbance) but have not previously been assessed in the context of social functioning. Here we investigated the impact of psychomotor disturbance in depression on physical responsive behavior in both an experimental and observational setting. Methods: In Experiment 1, we examined motor disturbance in depression in response to salient emotional sounds, using a laboratory-based effortful motor task. In Experiment 2, we explored whether psychomotor disturbance was apparent in real-life social interactions. Using mother-infant interactions as a model affective social situation, we compared physical behaviors of mothers with and without postnatal depression (PND). Results: We found impairments in precise, controlled psychomotor performance in adults with depression relative to healthy adults (Experiment 1). Despite this disruption, all adults showed enhanced performance following exposure to highly salient emotional cues (infant cries). Examining real-life interactions, we found differences in physical movements, namely reduced affective touching, in mothers with PND responding to their infants, compared to healthy mothers (Experiment 2). Conclusions: Together, these findings suggest that psychomotor disturbance may be an important feature of depression that can impair social functioning. Future work investigating whether improvements in physical movement in depression could have a positive impact on social interactions would be of much interest. PMID:25741255

  17. Four years of experimental warming do not modify the interaction between subalpine shrub species.

    PubMed

    Anadon-Rosell, Alba; Ninot, Josep M; Palacio, Sara; Grau, Oriol; Nogués, Salvador; Navarro, Enrique; Sancho, M Carmen; Carrillo, Empar

    2017-04-01

    Climate warming can lead to changes in alpine plant species interactions through modifications in environmental conditions, which may ultimately cause drastic changes in plant communities. We explored the effects of 4 years of experimental warming with open-top chambers (OTC) on Vaccinium myrtillus performance and its interaction with neighbouring shrubs at the Pyrenean treeline ecotone. We examined the effects of warming on height, above-ground (AG) and below-ground (BG) biomass and the C and N concentration and isotope composition of V. myrtillus growing in pure stands or in stands mixed with Vaccinium uliginosum or Rhododendron ferrugineum. We also analysed variations in soil N concentrations, rhizosphere C/N ratios and the functional diversity of the microbial community, and evaluated whether warming altered the biomass, C and N concentration and isotope composition of V. uliginosum in mixed plots. Our results showed that warming induced positive changes in the AG growth of V. myrtillus but not BG, while V. uliginosum did not respond to warming. Vaccinium myrtillus performance did not differ between stand types under increased temperatures, suggesting that warming did not induce shifts in the interaction between V. myrtillus and its neighbouring species. These findings contrast with previous studies in which species interactions changed when temperature was modified. Our results show that species interactions can be less responsive to warming in natural plant communities than in removal experiments, highlighting the need for studies involving the natural assembly of plant species and communities when exploring the effect of environmental changes on plant-plant interactions.

  18. Using Bayesian Nonparametric Hidden Semi-Markov Models to Disentangle Affect Processes during Marital Interaction

    PubMed Central

    Griffin, William A.; Li, Xun

    2016-01-01

    Sequential affect dynamics generated during the interaction of intimate dyads, such as married couples, are associated with a cascade of effects—some good and some bad—on each partner, close family members, and other social contacts. Although the effects are well documented, the probabilistic structures associated with micro-social processes connected to the varied outcomes remain enigmatic. Using extant data we developed a method of classifying and subsequently generating couple dynamics using a Hierarchical Dirichlet Process Hidden semi-Markov Model (HDP-HSMM). Our findings indicate that several key aspects of existing models of marital interaction are inadequate: affect state emissions and their durations, along with the expected variability differences between distressed and nondistressed couples are present but highly nuanced; and most surprisingly, heterogeneity among highly satisfied couples necessitate that they be divided into subgroups. We review how this unsupervised learning technique generates plausible dyadic sequences that are sensitive to relationship quality and provide a natural mechanism for computational models of behavioral and affective micro-social processes. PMID:27187319

  19. Plant compartment and biogeography affect microbiome composition in cultivated and native Agave species.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The primary goal of this research was to investigate the prokaryotic and fungal communities associated with the bulk soil, the rhizosphere, the phyllosphere, and the root and leaf endospheres, for three Agave species: the cultivated Agave tequilana and the native species, A. salmiana and A. deserti ...

  20. Seasonal Influences on Ground-Surface Water Interactions in an Arsenic-Affected Aquifer in Cambodia

    NASA Astrophysics Data System (ADS)

    Richards, L. A.; Magnone, D.; Van Dongen, B.; Bryant, C.; Boyce, A.; Ballentine, C. J.; Polya, D. A.

    2015-12-01

    Millions of people in South and Southeast Asia consume drinking water daily which contains dangerous levels of arsenic exceeding health-based recommendations [1]. A key control on arsenic mobilization in aquifers in these areas has been controversially identified as the interaction of 'labile' organic matter contained in surface waters with groundwaters and sediments at depth [2-4], which may trigger the release of arsenic from the solid- to aqueous-phase via reductive dissolution of iron-(hyr)oxide minerals [5]. In a field site in Kandal Province, Cambodia, which is an arsenic-affected area typical to others in the region, there are strong seasonal patterns in groundwater flow direction, which are closely related to monsoonal rains [6] and may contribute to arsenic release in this aquifer. The aim of this study is to explore the implications of the high susceptibility of this aquifer system to seasonal changes on potential ground-surface water interactions. The main objectives are to (i) identify key zones where there are likely ground-surface water interactions, (ii) assess the seasonal impact of such interactions and (iii) quantify the influence of interactions using geochemical parameters (such as As, Fe, NO3, NH4, 14C, 3T/3He, δ18O, δ2H). Identifying the zones, magnitude and seasonal influence of ground-surface water interactions elucidates new information regarding potential locations/pathways of arsenic mobilization and/or transport in affected aquifers and may be important for water management strategies in affected areas. This research is supported by NERC (NE/J023833/1) to DP, BvD and CJB and a NERC PhD studentship (NE/L501591/1) to DM. References: [1] World Health Organization, 2008. [2] Charlet & Polya (2006), Elements, 2, 91-96. [3] Harvey et al. (2002), Science, 298, 1602-1606. [4] Lawson et al. (2013), Env. Sci. Technol. 47, 7085 - 7094. [5] Islam et al. (2004), Nature, 430, 68-71. [6] Benner et al. (2008) Appl. Geochem. 23(11), 3072 - 3087.

  1. Verbal marking of affect by children with Asperger Syndrome and high functioning autism during spontaneous interactions with family members.

    PubMed

    Müller, Eve; Schuler, Adriana

    2006-11-01

    Verbal marking of affect by older children with Asperger Syndrome (AS) and high functioning autism (HFA) during spontaneous interactions is described. Discourse analysis of AS and HFA and typically developing children included frequency of affective utterances, affective initiations, affective labels and affective explanations, attribution of affective responses to self and others, and positive and negative markers of affect. Findings indicate that children with AS and HFA engaged in a higher proportion of affect marking and provided a higher proportion of affective explanations than typically developing children, yet were less likely to initiate affect marking sequences or talk about the affective responses of others. No significant differences were found between groups in terms of the marking of positive and negative affect.

  2. Species interactions determine the spatial mortality patterns emerging in plant communities after extreme events

    PubMed Central

    Liao, Jinbao; Bogaert, Jan; Nijs, Ivan

    2015-01-01

    Gap disturbance is assumed to maintain species diversity by creating environmental heterogeneity. However, little is known about how interactions with neighbours, such as competition and facilitation, alter the emerging gap patterns after extreme events. Using a spatially explicit community model we demonstrate that negative interactions, especially intraspecific competition, greatly promote both average gap size and gap-size diversity relative to positive interspecific interaction. This suggests that competition would promote diversity maintenance but also increase community invasibility, as large gaps with a wide size variety provide more diverse niches for both local and exotic species. Under interspecific competition, both gap metrics interestingly increased with species richness, while they were reduced under intraspecific competition. Having a wider range of species interaction strengths led to a smaller average gap size only under intraspecific competition. Increasing conspecific clumping induced larger gaps with more variable sizes under intraspecific competition, in contrast to interspecific competition. Given the range of intraspecific clumping in real communities, models or experiments based on randomly synthesized communities may yield biased estimates of the opportunities for potential colonizers to fill gaps. Overall, our “static” model on gap formation offers perspectives to better predict recolonization opportunity and thus community secondary succession under extreme event regimes. PMID:26054061

  3. Species interactions determine the spatial mortality patterns emerging in plant communities after extreme events.

    PubMed

    Liao, Jinbao; Bogaert, Jan; Nijs, Ivan

    2015-06-08

    Gap disturbance is assumed to maintain species diversity by creating environmental heterogeneity. However, little is known about how interactions with neighbours, such as competition and facilitation, alter the emerging gap patterns after extreme events. Using a spatially explicit community model we demonstrate that negative interactions, especially intraspecific competition, greatly promote both average gap size and gap-size diversity relative to positive interspecific interaction. This suggests that competition would promote diversity maintenance but also increase community invasibility, as large gaps with a wide size variety provide more diverse niches for both local and exotic species. Under interspecific competition, both gap metrics interestingly increased with species richness, while they were reduced under intraspecific competition. Having a wider range of species interaction strengths led to a smaller average gap size only under intraspecific competition. Increasing conspecific clumping induced larger gaps with more variable sizes under intraspecific competition, in contrast to interspecific competition. Given the range of intraspecific clumping in real communities, models or experiments based on randomly synthesized communities may yield biased estimates of the opportunities for potential colonizers to fill gaps. Overall, our "static" model on gap formation offers perspectives to better predict recolonization opportunity and thus community secondary succession under extreme event regimes.

  4. Does population size affect genetic diversity? A test with sympatric lizard species

    PubMed Central

    Hague, M T J; Routman, E J

    2016-01-01

    Genetic diversity is a fundamental requirement for evolution and adaptation. Nonetheless, the forces that maintain patterns of genetic variation in wild populations are not completely understood. Neutral theory posits that genetic diversity will increase with a larger effective population size and the decreasing effects of drift. However, the lack of compelling evidence for a relationship between genetic diversity and population size in comparative studies has generated some skepticism over the degree that neutral sequence evolution drives overall patterns of diversity. The goal of this study was to measure genetic diversity among sympatric populations of related lizard species that differ in population size and other ecological factors. By sampling related species from a single geographic location, we aimed to reduce nuisance variance in genetic diversity owing to species differences, for example, in mutation rates or historical biogeography. We compared populations of zebra-tailed lizards and western banded geckos, which are abundant and short-lived, to chuckwallas and desert iguanas, which are less common and long-lived. We assessed population genetic diversity at three protein-coding loci for each species. Our results were consistent with the predictions of neutral theory, as the abundant species almost always had higher levels of haplotype diversity than the less common species. Higher population genetic diversity in the abundant species is likely due to a combination of demographic factors, including larger local population sizes (and presumably effective population sizes), faster generation times and high rates of gene flow with other populations. PMID:26306730

  5. The Role of Cognitive and Affective Empathy in Spouses' Support Interactions: An Observational Study

    PubMed Central

    Verhofstadt, Lesley; Devoldre, Inge; Buysse, Ann; Stevens, Michael; Hinnekens, Céline; Ickes, William; Davis, Mark

    2016-01-01

    The present study examined how support providers’ empathic dispositions (dispositional perspective taking, empathic concern, and personal distress) as well as their situational empathic reactions (interaction-based perspective taking, empathic concern, and personal distress) relate to the provision of spousal support during observed support interactions. Forty-five committed couples provided questionnaire data and participated in two ten-minute social support interactions designed to assess behaviors when partners are offering and soliciting social support. A video-review task was used to assess situational forms of perspective taking (e.g., empathic accuracy), empathic concern and personal distress. Data were analyzed by means of the multi-level Actor-Partner Interdependence Model. Results revealed that providers scoring higher on affective empathy (i.e., dispositional empathic concern), provided lower levels of negative support. In addition, for male partners, scoring higher on cognitive empathy (i.e., situational perspective taking) was related to lower levels of negative support provision. For both partners, higher scores on cognitive empathy (i.e., situational perspective taking) correlated with more instrumental support provision. Male providers scoring higher on affective empathy (i.e., situational personal distress) provided higher levels of instrumental support. Dispositional perspective taking was related to higher scores on emotional support provision for male providers. The current study furthers our insight into the empathy-support link, by revealing differential effects (a) for men and women, (b) of both cognitive and affective empathy, and (c) of dispositional as well as situational empathy, on different types of support provision. PMID:26910769

  6. Approaching the Functional Annotation of Fungal Virulence Factors Using Cross-Species Genetic Interaction Profiling

    PubMed Central

    Brown, Jessica C. S.; Madhani, Hiten D.

    2012-01-01

    In many human fungal pathogens, genes required for disease remain largely unannotated, limiting the impact of virulence gene discovery efforts. We tested the utility of a cross-species genetic interaction profiling approach to obtain clues to the molecular function of unannotated pathogenicity factors in the human pathogen Cryptococcus neoformans. This approach involves expression of C. neoformans genes of interest in each member of the Saccharomyces cerevisiae gene deletion library, quantification of their impact on growth, and calculation of the cross-species genetic interaction profiles. To develop functional predictions, we computed and analyzed the correlations of these profiles with existing genetic interaction profiles of S. cerevisiae deletion mutants. For C. neoformans LIV7, which has no S. cerevisiae ortholog, this profiling approach predicted an unanticipated role in the Golgi apparatus. Validation studies in C. neoformans demonstrated that Liv7 is a functional Golgi factor where it promotes the suppression of the exposure of a specific immunostimulatory molecule, mannose, on the cell surface, thereby inhibiting phagocytosis. The genetic interaction profile of another pathogenicity gene that lacks an S. cerevisiae ortholog, LIV6, strongly predicted a role in endosome function. This prediction was also supported by studies of the corresponding C. neoformans null mutant. Our results demonstrate the utility of quantitative cross-species genetic interaction profiling for the functional annotation of fungal pathogenicity proteins of unknown function including, surprisingly, those that are not conserved in sequence across fungi. PMID:23300468

  7. Approaching the functional annotation of fungal virulence factors using cross-species genetic interaction profiling.

    PubMed

    Brown, Jessica C S; Madhani, Hiten D

    2012-01-01

    In many human fungal pathogens, genes required for disease remain largely unannotated, limiting the impact of virulence gene discovery efforts. We tested the utility of a cross-species genetic interaction profiling approach to obtain clues to the molecular function of unannotated pathogenicity factors in the human pathogen Cryptococcus neoformans. This approach involves expression of C. neoformans genes of interest in each member of the Saccharomyces cerevisiae gene deletion library, quantification of their impact on growth, and calculation of the cross-species genetic interaction profiles. To develop functional predictions, we computed and analyzed the correlations of these profiles with existing genetic interaction profiles of S. cerevisiae deletion mutants. For C. neoformans LIV7, which has no S. cerevisiae ortholog, this profiling approach predicted an unanticipated role in the Golgi apparatus. Validation studies in C. neoformans demonstrated that Liv7 is a functional Golgi factor where it promotes the suppression of the exposure of a specific immunostimulatory molecule, mannose, on the cell surface, thereby inhibiting phagocytosis. The genetic interaction profile of another pathogenicity gene that lacks an S. cerevisiae ortholog, LIV6, strongly predicted a role in endosome function. This prediction was also supported by studies of the corresponding C. neoformans null mutant. Our results demonstrate the utility of quantitative cross-species genetic interaction profiling for the functional annotation of fungal pathogenicity proteins of unknown function including, surprisingly, those that are not conserved in sequence across fungi.

  8. Tempo and mode in fossil molluscs: Investigating organism-environment interactions, species, and speciation

    SciTech Connect

    Geary, D.H. )

    1992-01-01

    After 20 years of investigation into the tempo and mode of species-level change in the fossil record, it is clear that both punctuated equilibrium and phyletic gradualism occur, as do a variety of intermediate patterns. Important questions regarding the maintenance and diversification of species remain, however. The author documents a variety of evolutionary patterns from gastropods and bivalves, and uses these to discuss two basic issues: environment-organism interactions over time, and the importance of information on geographic variation. The tempo of morphological change is an expression of the interaction of organisms and their environment. The initial over which new species appear may be a geologic instant'' (Melanopsis gastropods), or may last 10[sup 4]--10[sup 5] years (Prunum gastropods), or 10[sup 6] years (Melanopsis). This wide range of intervals indicates a variety of tempos of environmental change, and/or different kinds of organismal responses. Analysis of geographic variation is of critical importance in understanding species and speciation, yet is lacking in many paleontological studies. An example of the utility of geographic information is a study of the muricid gastropod Acanthina, which demonstrates how a geographically localized form may spread through a species range. Another example involves a species of Pleuriocardia in stasis: geographic variation among roughly correlative samples greatly exceeds long-term temporal variation. Considerations of the mechanisms for stasis and change must take into account such intraspecific variation.

  9. Interaction between common organic acids and trace nucleation species in the Earth's atmosphere.

    PubMed

    Xu, Yisheng; Nadykto, Alexey B; Yu, Fangqun; Herb, J; Wang, Wei

    2010-01-14

    Atmospheric aerosols formed via nucleation in the Earth's atmosphere play an important role in the aerosol radiative forcing associated directly with global climate changes and public health. Although it is well-known that atmospheric aerosol particles contain organic species, the chemical nature of and physicochemical processes behind atmospheric nucleation involving organic species remain unclear. In the present work, the interaction of common organic acids with molecular weights of 122, 116, 134, 88, 136, and 150 (benzoic, maleic, malic, pyruvic, phenylacetic, and tartaric acids) with nucleation precursors and charged trace species has been investigated. We found a moderate strong effect of the organic species on the stability of neutral and charged ionic species. In most cases, the free energies of the mixed H(2)SO(4)-organic acid dimer formation are within 1-1.5 kcal mol(-1) of the (H(2)SO(4))(NH(3)) formation energy. The interaction of the organic acids with trace ionic species is quite strong, and the corresponding free energies far exceed those of the (H(3)O(+))(H(2)SO(4)) and (H(3)O(+))(H(2)SO(4))(2) formation. These considerations lead us to conclude that the aforementioned organic acids may possess a substantial capability of stabilizing both neutral and positively charged prenucleation clusters, and thus, they should be studied further with regard to their involvement in the gas-to-particle conversion in the Earth's atmosphere.

  10. Maternal interaction style in affective disordered, physically ill, and normal women.

    PubMed

    Hamilton, E B; Jones, M; Hammen, C

    1993-09-01

    Affective style (AS) and communication deviance (CD) have been suggested as markers of dysfunctional family environments that may be associated with psychiatric illness. Studies have focused mainly on parental responses during family interactions when an offspring is the identified patient. The present study is unique in examining AS and CD in mothers with unipolar depression, bipolar disorder, or chronic physical illness, and in normal controls. The sample consisted of 64 mothers with children ages 8 to 16. Unipolar mothers were more likely to show negative AS than were any other maternal group. There were no group differences for CD. Chronic stress, few positive life events, and single parenting were associated with AS. CD was associated solely with lower socioeconomic status. Results suggest that dysfunctional interactions are determined not only by maternal psychopathology, but also by an array of contextual factors that are related to the quality of the family environment.

  11. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    NASA Astrophysics Data System (ADS)

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-07-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services.

  12. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    PubMed Central

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-01-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services. PMID:25005713

  13. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem.

    PubMed

    Zaller, Johann G; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-07-09

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services.

  14. Do method and species lifestyle affect measures of maximum metabolic rate in fishes?

    PubMed

    Killen, S S; Norin, T; Halsey, L G

    2017-03-01

    The rate at which active animals can expend energy is limited by their maximum aerobic metabolic rate (MMR). Two methods are commonly used to estimate MMR as oxygen uptake in fishes, namely during prolonged swimming or immediately following brief exhaustive exercise, but it is unclear whether they return different estimates of MMR or whether their effectiveness for estimating MMR varies among species with different lifestyles. A broad comparative analysis of MMR data from 121 fish species revealed little evidence of different results between the two methods, either for fishes in general or for species of benthic, benthopelagic or pelagic lifestyles.

  15. Growth in two common gardens reveals species by environment interaction in carbon isotope discrimination of Eucalyptus.

    PubMed

    Turner, Neil C; Schulze, Ernst-Detlef; Nicolle, Dean; Kuhlmann, Iris

    2010-06-01

    One-year-old sun leaves of 60 species of Eucalyptus were collected in August 2005 at an arboretum in South Australia with a mean annual rainfall of 427 mm, and 14 of the same species were sampled at an arboretum in Western Australia with a mean annual rainfall of 216 mm. We determined the genetic and phenotypic variation in carbon isotope composition (delta13C), specific leaf area (SLA) and nitrogen content per unit area of the species at each site. There were very significant (P < 0.001) differences in delta13C among the species at both sites. The mean delta13C of the 60 species at the wetter site was -27.6 per thousand (from -25.8 per thousand in Eucalyptus youngiana to -29.9 per thousand in Eucalyptus salicola) and of the 14 species at the drier site was -25.3 per thousand (from -23.7 per thousand in Eucalyptus ravida to -27.3 per thousand in Eucalyptus ewartiana). Of the 14 species common to both sites, four species had similar values of delta13C at the two sites despite the differences in rainfall, whereas in others the values of delta13C were significantly (P < 0.001) lower (more negative) at the wet than at the dry site. The SLA and nitrogen content per unit leaf area also differed significantly among the species (P < 0.001), but there was not a common relationship between delta13C and SLA or between delta13C and nitrogen content at the two sites. The strong species by environment interaction resulted from some species demonstrating phenotypic plasticity for delta13C, while others were inherently stable across environments.

  16. Social defeat interacts with Disc1 mutations in the mouse to affect behavior.

    PubMed

    Haque, F Nipa; Lipina, Tatiana V; Roder, John C; Wong, Albert H C

    2012-08-01

    DISC1 (Disrupted-in-schizophrenia 1) is a strong candidate susceptibility gene for psychiatric disease that was originally discovered in a family with a chromosomal translocation severing this gene. Although the family members with the translocation had an identical genetic mutation, their clinical diagnosis and presentation varied significantly. Gene-environment interactions have been proposed as a mechanism underlying the complex heritability and variable phenotype of psychiatric disorders such as major depressive disorder and schizophrenia. We hypothesized that gene-environment interactions would affect behavior in a mutant Disc1 mouse model. We examined the effect of chronic social defeat (CSD) as an environmental stressor in two lines of mice carrying different Disc1 point mutations, on behaviors relevant to psychiatric illness: locomotion in a novel open field (OF), pre-pulse inhibition (PPI) of the acoustic startle response, latent inhibition (LI), elevated plus maze (EPM), forced swim test (FST), sucrose consumption (SC), and the social interaction task for sociability and social novelty (SSN). We found that Disc1-L100P +/- and wild-type mice have similar anxiety responses to CSD, while Q31L +/- mice had a very different response. We also found evidence of significant gene-environment interactions in the OF, EPM and SSN.

  17. Antagonistic interactions between an invasive alien and a native coccinellid species may promote coexistence.

    PubMed

    Hentley, William T; Vanbergen, Adam J; Beckerman, Andrew P; Brien, Melanie N; Hails, Rosemary S; Jones, T Hefin; Johnson, Scott N

    2016-07-01

    Despite the capacity of invasive alien species to alter ecosystems, the mechanisms underlying their impact remain only partly understood. Invasive alien predators, for example, can significantly disrupt recipient communities by consuming prey species or acting as an intraguild predator (IGP). Behavioural interactions are key components of interspecific competition between predators, yet these are often overlooked invasion processes. Here, we show how behavioural, non-lethal IGP interactions might facilitate the establishment success of an invading alien species. We experimentally assessed changes in feeding behaviour (prey preference and consumption rate) of native UK coccinellid species (Adalia bipunctata and Coccinella septempunctata), whose populations are, respectively, declining and stable, when exposed to the invasive intraguild predator, Harmonia axyridis. Using a population dynamics model parameterized with these experimental data, we predicted how intraguild predation, accommodating interspecific behavioural interactions, might impact the abundance of the native and invasive alien species over time. When competing for the same aphid resource, the feeding rate of A. bipunctata significantly increased compared to the feeding in isolation, while the feeding rate of H. axyridis significantly decreased. This suggests that despite significant declines in the UK, A. bipunctata is a superior competitor to the intraguild predator H. axyridis. In contrast, the behaviour of non-declining C. septempunctata was unaltered by the presence of H. axyridis. Our experimental data show the differential behavioural plasticity of competing native and invasive alien predators, but do not explain A. bipunctata declines observed in the UK. Using behavioural plasticity as a parameter in a population dynamic model for A. bipunctata and H. axyridis, coexistence is predicted between the native and invasive alien following an initial period of decline in the native species. We

  18. Drought and air warming affect the species-specific levels of stress-related foliar metabolites of three oak species on acidic and calcareous soil.

    PubMed

    Hu, Bin; Simon, Judy; Rennenberg, Heinz

    2013-05-01

    Climate change as projected for Central Europe will lead to prolonged periods of summer drought and enhanced air temperature. Thus, forest management practices are required to take into account how species performance is adapted to cope with these climate changes. Oak trees may play a major role in future forests because of their relative drought-tolerance compared with other species like beech. Therefore, this study investigated the stress responses (i.e., anti-oxidants, free amino acids) in the leaves of three widely distributed oak species in Central Europe (i.e., Quercus robur L., Q. petraea [Matt.] Libel., Q. pubescens Willd.) to drought, air warming and the combination of drought plus air warming under controlled conditions after periods of spring drought, a short rewetting and summer drought. We quantified foliar levels of thiols, ascorbate, and free amino compounds in Q robur, Q. petraea and Q. pubescens. Our study showed that oak saplings had increased levels of γ-glutamylcysteine and total glutathione and proline with drought and air warming. Foliar ascorbate, glutathione disulfide and dehydroascorbic acid levels were not affected. The comparison of stress responses to drought and/or air warming between the three species showed higher foliar thiol levels in Q. robur and Q. pubescens compared with Q. petraea. For total and reduced ascorbic acid and γ-aminobutyric acid, the highest levels were found in Q. robur. In conclusion, our study showed that foliar anti-oxidant and free amino acid levels were significantly affected by drought plus air warming; however, this effect was species-dependent with the drought-tolerant species of Q. pubescens having the highest reactive oxygen species scavenging capacity among three tested oak species. Furthermore, stress responses as shown by increased levels of foliar anti-oxidants and free amino acids differ between calcareous and acidic soil indicating that the capacities of anti-oxidative defense and osmotic stress

  19. Landscape composition, patch size, and distance to edges: Interactions affecting duck reproductive success

    USGS Publications Warehouse

    Horn, David Joseph; Phillips, Michael L.; Koford, Rolf R.; Clark, William R.; Sovada, Marsha A.; Greenwood, Raymond J.

    2005-01-01

    Prairies and other North American grasslands, although highly fragmented, provide breeding habitat for a diverse array of species, including species of tremendous economic and ecological importance. Conservation and management of these species requires some understanding of how reproductive success is affected by edge effects, patch size, and characteristics of the landscape. We examined how differences in the percentage of grassland in the landscape influenced the relationships between the success of nests of upland-nesting ducks and (1) field size and (2) distance to nearest field and wetland edges. We collected data on study areas composed of 15–20% grassland and areas composed of 45–55% grassland in central North Dakota, USA during the 1996 and 1997 nesting seasons. Daily survival rates (DSRs) of duck nests were greater in study areas with 45–55% grassland than with 15–20% grassland. Within study areas, we detected a curvilinear relationship between DSR and field size: DSRs were highest in small and large fields and lowest in moderately sized fields. In study areas with 15–20% grassland, there was no relationship between probability of hatching and distance to nearest field edge, whereas in study areas with 45–55% grassland, there was a positive relationship between these two variables. Results of this study support the conclusion that both landscape composition and configuration affect reproductive success of ground-nesting birds. We are prompted to question conservation strategies that favor clustering moderately sized patches of nesting habitat within agricultural landscapes because our results show that such patches would have low nest success, most likely caused by predation. Understanding the pattern of nest success, and the predator–prey mechanisms that produce the pattern, will enable design of patch configurations that are most conducive to meeting conservation goals.

  20. When sad groups expect to meet again: interactive affective sharing and future interaction expectation as determinants of work groups' analytical and creative task performance.

    PubMed

    Klep, Annefloor H M; Wisse, Barbara; van der Flier, Henk

    2013-12-01

    The present study examines the moderating role of future interaction expectation in the relationship between affective sharing and work groups' task performance. We argue that group affect, a group defining characteristic, becomes more salient to its members when it is interactively shared, and that the anticipation of future interaction may strengthen the effects of group defining characteristics on subsequent group member behaviour. As a consequence, interactive sharing (vs. non-interactive sharing) of negative affect is more likely to influence work group outcomes when group members expect to meet again. Results from a laboratory experiment with 66 three-person work groups indeed show that interactively shared (vs. non-interactively shared) negative affect facilitated work groups' analytical task performance, whereas it inhibited performance on a creative fluency task when groups have expectations of future interaction and not when they do not have such expectations. The discussion focuses on how these results add to theory on group affect and contribute to insights in the effects of future interaction expectation.

  1. Estimating How Inflated or Obscured Effects of Climate Affect Forecasted Species Distribution

    PubMed Central

    Real, Raimundo; Romero, David; Olivero, Jesús; Estrada, Alba; Márquez, Ana L.

    2013-01-01

    Climate is one of the main drivers of species distribution. However, as different environmental factors tend to co-vary, the effect of climate cannot be taken at face value, as it may be either inflated or obscured by other correlated factors. We used the favourability models of four species (Alytes dickhilleni, Vipera latasti, Aquila fasciata and Capra pyrenaica) inhabiting Spanish mountains as case studies to evaluate the relative contribution of climate in their forecasted favourability by using variation partitioning and weighting the effect of climate in relation to non-climatic factors. By calculating the pure effect of the climatic factor, the pure effects of non-climatic factors, the shared climatic effect and the proportion of the pure effect of the climatic factor in relation to its apparent effect (ρ), we assessed the apparent effect and the pure independent effect of climate. We then projected both types of effects when modelling the future favourability for each species and combination of AOGCM-SRES (two Atmosphere-Ocean General Circulation Models: CGCM2 and ECHAM4, and two Special Reports on Emission Scenarios (SRES): A2 and B2). The results show that the apparent effect of climate can be either inflated (overrated) or obscured (underrated) by other correlated factors. These differences were species-specific; the sum of favourable areas forecasted according to the pure climatic effect differed from that forecasted according to the apparent climatic effect by about 61% on average for one of the species analyzed, and by about 20% on average for each of the other species. The pure effect of future climate on species distributions can only be estimated by combining climate with other factors. Transferring the pure climatic effect and the apparent climatic effect to the future delimits the maximum and minimum favourable areas forecasted for each species in each climate change scenario. PMID:23349726

  2. Estimating how inflated or obscured effects of climate affect forecasted species distribution.

    PubMed

    Real, Raimundo; Romero, David; Olivero, Jesús; Estrada, Alba; Márquez, Ana L

    2013-01-01

    Climate is one of the main drivers of species distribution. However, as different environmental factors tend to co-vary, the effect of climate cannot be taken at face value, as it may be either inflated or obscured by other correlated factors. We used the favourability models of four species (Alytes dickhilleni, Vipera latasti, Aquila fasciata and Capra pyrenaica) inhabiting Spanish mountains as case studies to evaluate the relative contribution of climate in their forecasted favourability by using variation partitioning and weighting the effect of climate in relation to non-climatic factors. By calculating the pure effect of the climatic factor, the pure effects of non-climatic factors, the shared climatic effect and the proportion of the pure effect of the climatic factor in relation to its apparent effect (ρ), we assessed the apparent effect and the pure independent effect of climate. We then projected both types of effects when modelling the future favourability for each species and combination of AOGCM-SRES (two Atmosphere-Ocean General Circulation Models: CGCM2 and ECHAM4, and two Special Reports on Emission Scenarios (SRES): A2 and B2). The results show that the apparent effect of climate can be either inflated (overrated) or obscured (underrated) by other correlated factors. These differences were species-specific; the sum of favourable areas forecasted according to the pure climatic effect differed from that forecasted according to the apparent climatic effect by about 61% on average for one of the species analyzed, and by about 20% on average for each of the other species. The pure effect of future climate on species distributions can only be estimated by combining climate with other factors. Transferring the pure climatic effect and the apparent climatic effect to the future delimits the maximum and minimum favourable areas forecasted for each species in each climate change scenario.

  3. Above and belowground connections and species interactions: Controls over ecosystem fluxes

    SciTech Connect

    Trowbridge, Amy Marie; Phillips, Richard; Stoy, Paul Christopher

    2016-11-01

    The ultimate goal of this work was to quantify soil and volatile organic compound fluxes as a function of tree species and associated mycorrhizal associations in an intact forest, but also to describe the physical and biological factors that control these emissions. The results of this research lay the foundation toward an improved mechanistic understanding of carbon pathways, fluxes, and ecosystem function, ultimately improving the representation of forest ecosystems in Earth System models. To this end, a multidisciplinary approach was necessary to fill a critical gap in our understanding of how soil and root processes may influence whole-ecosystem carbon-based volatile fluxes in the face of a rapidly changing climate. We developed a series of novel sampling protocols and coupled a variety of advanced analytical techniques, resulting in findings relevant across disciplines. Furthermore, we leveraged existing infrastructure, research sites, and datasets to design a low-cost exploratory project that links belowground processes, soil volatile emissions, and total ecosystem carbon budgets. Measurements from soil collars installed across a species/mycorrhizal gradient at the DOE-supported Moran Monroe State Forest Ameriflux tower site suggest that leaf litter is the primary source of belowground and forest floor volatile emissions, but the strength of this source is significantly affected not only by leaf litter type, but the strength of the soil as a sink. Results suggest that the strength of the sink is influenced by tree species-specific associated microbial communities that change throughout the season as a function of temperature, soil moisture, leaf litter inputs, and phenology. The magnitude of the observed volatile fluxes from the forest floor is small relative to total aboveground ecosystem flux, but the contribution of these emissions to volatile-mediated ecological interactions and soil processes (e.g. nitrification) varies substantially across the growing

  4. Interactions of methanol, ethanol, and 1-propanol with polar and nonpolar species in water at cryogenic temperatures.

    PubMed

    Souda, Ryutaro

    2017-01-18

    Methanol is known as a strong inhibitor of hydrate formation, but clathrate hydrates of ethanol and 1-propanol can be formed in the presence of help gases. To elucidate the hydrophilic and hydrophobic effects of alcohols, their interactions with simple solute species are investigated in glassy, liquid, and crystalline water using temperature-programmed desorption and time-of-flight secondary ion mass spectrometry. Nonpolar solute species embedded underneath amorphous solid water films are released during crystallization, but they tend to withstand water crystallization under the coexistence of methanol additives. The CO2 additives are released after crystallization along with methanol desorption. These results suggest strongly that nonpolar species that are hydrated (i.e., caged) associatively with methanol can withstand water crystallization. In contrast, ethanol and 1-propanol additives weakly affect the dehydration of nonpolar species during water crystallization, suggesting that the former tend to be caged separately from the latter. The hydrophilic vs. hydrophobic behavior of alcohols, which differs according to the aliphatic group length, also manifests itself in the different abilities of surface segregation of alcohols and their effects on the water crystallization kinetics.

  5. Time and concentration dependency in the potentially affected fraction of species: the case of hydrogen peroxide treatment of ballast water.

    PubMed

    Smit, Mathijs G D; Ebbens, Eltjo; Jak, Robbert G; Huijbregtst, Mark A J

    2008-03-01

    Transport of large volumes of ballast water contributes greatly to invasions of species. Hydrogen peroxide (H2O2) can be used as a disinfectant to prevent the spread of exotic species via ballast water. Instead of using environmental risk assessment techniques for protecting a certain fraction of the species from being affected, the present study aimed to apply these techniques to define treatment regimes of H2O2 and effectively eliminate as many species as possible. Based on time-dependent dose-response curves for five marine species (Corophium volutator, Artemia salina, Brachionus plicatilis, Dunaliella teriolecta, and Skeletonema costatum), time-dependent species-sensitivity distributions (SSDs) were derived for different effect sizes. The present study showed that H2O2 can be used effectively to treat ballast water but that relatively high concentrations and long treatment durations are required to eliminate the vast majority of species in ballast water. The described toxicant effectiveness approach using SSDs also has other potential fields of application, including short-term application of biocides.

  6. Shifting species interaction in soil microbial community and its influence on ecosystem functions modulating.

    PubMed

    Li, Hua; Colica, Giovanni; Wu, Pei-pei; Li, Dunhai; Rossi, Federico; De Philippis, Roberto; Liu, Yongding

    2013-04-01

    The supportive and negative evidence for the stress gradient hypothesis (SGH) led to an ongoing debate among ecologists and called for new empirical and theoretical work. In this study, we took various biological soil crust (BSCs) samples along a spatial gradient with four environmental stress levels to examine the fitness of SGH in microbial interactions and evaluate its influence on biodiversity-function relationships in BSCs. A new assessment method of species interactions within hard-cultured invisible soil community was employed, directly based on denaturing gradient gel electrophoresis fingerprint images. The results showed that biotic interactions in soil phototroph community dramatically shifted from facilitation to dominant competition with the improvement of microhabitats. It offered new evidence, which presented a different perspective on the hypothesis that the relative importance of facilitation and competition varies inversely along the gradient of abiotic stress. The path analysis indicated that influence of biotic interactions (r = 0.19, p < 0.05) on ecosystem functions is lower than other community properties (r = 0.62, p < 0.001), including soil moisture, crust coverage, and biodiversity. Furthermore, the correlation between species interactions and community properties was non-significant with low negative influence (r = -0.27, p > 0.05). We demonstrate that the inversion of biotic interaction as a response to the gradient of abiotic stresses existed not only in the visible plant community but also in the soil microbial community.

  7. Sexual competition and N supply interactively affect the dimorphism and competiveness of opposite sexes in Populus cathayana.

    PubMed

    Chen, Juan; Dong, Tingfa; Duan, Baoli; Korpelainen, Helena; Niinemets, Ülo; Li, Chunyang

    2015-07-01

    Several important dioecious species show sexual spatial segregation (SSS) along environmental gradients that have significant ecological effect on terrestrial ecosystem. However, little attention has been paid to understanding of how males and females respond to environmental gradients and sexual competition. We compared eco-physiological parameters of males and females of Populus cathayana under different sexual competition patterns and nitrogen (N) supply levels. We found that males and females interacting with the same or opposite sex showed significant differences in biomass partition, photosynthetic capacity, carbon (C) and N metabolism, and leaf ultrastructure, and that the sexual differences to competition were importantly driven by N supply. The intersexual competition was enhanced under high N, while the intrasexual competition among females was amplified under low N. Under high N, the intersexual competition stimulated the growth of the females and negatively affected the males. In contrast, under low N, the males exposed to intrasexual competition had the highest tolerance, whereas females exposed to intrasexual competition showed the lowest adaptation among all competition patterns. Sexual competition patterns and N supply levels significantly affected the sexual dimorphism and competitiveness, which may play an important role in spatial segregation of P. cathayana populations.

  8. Anatomical, chemical, and ecological factors affecting tree species choice in dendrochemistry studies

    SciTech Connect

    Cutter, B.E.; Guyette, R.P.

    1993-07-01

    Recently, element concentrations in tree rings have been used to monitor metal contamination, fertilization, and the effects of acid precipitation on soils. This has stimulated interest in which tree species may be suitable for use in studies of long-term trends in environmental chemistry. Potential radial translocation of elements across living boundaries can be a confounding factor in assessing environmental change. The selection of species which minimizes radial translocation of elements can be critical to the success of dendrochemical research. Criteria for selection of species with characteristics favorable for dendrochemical analysis are categorized into (1) habitat-based factors, (2) xylem-based factors, and (3) element-based factors. A wide geographic range and ecological amplitude provide an advantage in calibration and better controls on the effects of soil chemistry. The most important xylem-based criteria are heartwood moisture content, permeability, and the nature of the sapwood-heartwood transition. The element of interest is important in determining suitable tree species because all elements are not equally mobile or detectable in the xylem. Ideally, the tree species selected for dendrochemical study will be long-lived, grow on a wide range of sites over a large geographic distribution, have a distinct heartwood with a low number of rings in the sapwood, a low heartwood moisture content, and have low radial permeability. Recommended temperate zone North American species include white oak (Quercus alba L.), post oak (Q. stellate Wangenh.), eastern redcedar (funiperus virginiana L.), old-growth Douglas-fir [Pseudoaugu menziesii (Mirb.) Franco] and big sagebrush (Artemisia tridentata Nutt.). In addition, species such as bristlecone pine (Pinus aristata Engelm. syn. longaeva), old-growth redwood [Sequoia sempervirens (D. Don) Endl.], and giant sequoia [S. gigantea (Lindl.) Deene] may be suitable for local purposes. 118 refs., 2 tabs.

  9. Ecological opportunity and phenotypic plasticity interact to promote character displacement and species coexistence.

    PubMed

    Pfennig, David W; Rice, Amber M; Martin, Ryan A

    2006-03-01

    exploitable resources are available, character displacement is not guaranteed to transpire if species cannot utilize such resources expeditiously. Phenotypic plasticity provides a general and important mechanism for facilitating resource partitioning. Thus, by facilitating shifts in resource use, phenotypic plasticity and ecological opportunity may often interact to promote divergence and coexistence of competitors.

  10. Candida albicans Mycofilms Support Staphylococcus aureus Colonization and Enhances Miconazole Resistance in Dual-Species Interactions

    PubMed Central

    Kean, Ryan; Rajendran, Ranjith; Haggarty, Jennifer; Townsend, Eleanor M.; Short, Bryn; Burgess, Karl E.; Lang, Sue; Millington, Owain; Mackay, William G.; Williams, Craig; Ramage, Gordon

    2017-01-01

    Polymicrobial inter-kingdom biofilm infections represent a clinical management conundrum. The presence of co-isolation of bacteria and fungi complicates the ability to routinely administer single antimicrobial regimens, and synergy between the microorganisms influences infection severity. We therefore investigated the nosocomial pathogens Staphylococcus aureus and Candida albicans with respect to antimicrobial intervention. We characterized the interaction using biofilm assays and evaluated the effect of miconazole treatment using in vitro and in vivo assays. Finally, we assessed the impact of biofilm extracellular matrix (ECM) on these interactions. Data indicated that the C. albicans mycofilms supported adhesion and colonization by S. aureus through close interactions with hyphal elements, significantly increasing S. aureus biofilm formation throughout biofilm maturation. Miconazole sensitivity was shown to be reduced in both mono- and dual-species biofilms compared to planktonic cells. Within a three-dimensional biofilm model sensitivity was also hindered. Galleria mellonella survival analysis showed both enhanced pathogenicity of the dual-species infection, which was concomitantly desensitized to miconazole treatment. Analysis of the ECM revealed the importance of extracellular DNA, which supported the adhesion of S. aureus and the development of the dual-species biofilm structures. Collectively, these data highlight the clinical importance of dual-species inter-kingdom biofilm infections, though also provides translational opportunities to manage them more effectively. PMID:28280487

  11. ALS mutant SOD1 interacts with G3BP1 and affects stress granule dynamics.

    PubMed

    Gal, Jozsef; Kuang, Lisha; Barnett, Kelly R; Zhu, Brian Z; Shissler, Susannah C; Korotkov, Konstantin V; Hayward, Lawrence J; Kasarskis, Edward J; Zhu, Haining

    2016-10-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Mutations in Cu/Zn superoxide dismutase (SOD1) are responsible for approximately 20 % of the familial ALS cases. ALS-causing SOD1 mutants display a gain-of-toxicity phenotype, but the nature of this toxicity is still not fully understood. The Ras GTPase-activating protein-binding protein G3BP1 plays a critical role in stress granule dynamics. Alterations in the dynamics of stress granules have been reported in several other forms of ALS unrelated to SOD1. To our surprise, the mutant G93A SOD1 transgenic mice exhibited pathological cytoplasmic inclusions that co-localized with G3BP1-positive granules in spinal cord motor neurons. The co-localization was also observed in fibroblast cells derived from familial ALS patient carrying SOD1 mutation L144F. Mutant SOD1, unlike wild-type SOD1, interacted with G3BP1 in an RNA-independent manner. Moreover, the interaction is specific for G3BP1 since mutant SOD1 showed little interaction with four other RNA-binding proteins implicated in ALS. The RNA-binding RRM domain of G3BP1 and two particular phenylalanine residues (F380 and F382) are critical for this interaction. Mutant SOD1 delayed the formation of G3BP1- and TIA1-positive stress granules in response to hyperosmolar shock and arsenite treatment in N2A cells. In summary, the aberrant mutant SOD1-G3BP1 interaction affects stress granule dynamics, suggesting a potential link between pathogenic SOD1 mutations and RNA metabolism alterations in ALS.

  12. Interactive effects of elevated CO2 and precipitation change on leaf nitrogen of dominant Stipa L. species

    PubMed Central

    Shi, Yaohui; Zhou, Guangsheng; Jiang, Yanling; Wang, Hui; Xu, Zhenzhu; Song, Jian

    2015-01-01

    Nitrogen (N) serves as an important mineral element affecting plant productivity and nutritional quality. However, few studies have addressed the interactive effects of elevated CO2 and precipitation change on leaf N of dominant grassland genera such as Stipa L. This has restricted our understanding of the responses of grassland to climate change. We simulated the interactive effects of elevated CO2 concentration and varied precipitation on leaf N concentration (Nmass) of four Stipa species (Stipa baicalensis, Stipa bungeana, Stipa grandis, and Stipa breviflora; the most dominant species in arid and semiarid grassland) using open-top chambers (OTCs). The relationship between the Nmass of these four Stipa species and precipitation well fits a logarithmic function. The sensitivity of these four species to precipitation change was ranked as follows: S. bungeana > S. breviflora > S. baicalensis > S. grandis. The Nmass of S. bungeana was the most sensitive to precipitation change, while S. grandis was the least sensitive among these Stipa species. Elevated CO2 exacerbated the effect of precipitation on Nmass. Nmass decreased under elevated CO2 due to growth dilution and a direct negative effect on N assimilation. Elevated CO2 reduced Nmass only in a certain precipitation range for S. baicalensis (163–343 mm), S. bungeana (164–355 mm), S. grandis (148–286 mm), and S. breviflora (130–316 mm); severe drought or excessive rainfall would be expected to result in a reduced impact of elevated CO2. Elevated CO2 affected the Nmass of S. grandis only in a narrow precipitation range. The effect of elevated CO2 reached a maximum when the amount of precipitation was 253, 260, 217, and 222 mm for S. baicalensis, S. bungeana, S. grandis, and S. breviflora, respectively. The Nmass of S. grandis was the least sensitive to elevated CO2. The Nmass of S. breviflora was more sensitive to elevated CO2 under a drought condition compared with the other Stipa

  13. Interactive effects of elevated CO2 and precipitation change on leaf nitrogen of dominant Stipa L. species.

    PubMed

    Shi, Yaohui; Zhou, Guangsheng; Jiang, Yanling; Wang, Hui; Xu, Zhenzhu; Song, Jian

    2015-07-01

    Nitrogen (N) serves as an important mineral element affecting plant productivity and nutritional quality. However, few studies have addressed the interactive effects of elevated CO2 and precipitation change on leaf N of dominant grassland genera such as Stipa L. This has restricted our understanding of the responses of grassland to climate change. We simulated the interactive effects of elevated CO2 concentration and varied precipitation on leaf N concentration (Nmass) of four Stipa species (Stipa baicalensis, Stipa bungeana, Stipa grandis, and Stipa breviflora; the most dominant species in arid and semiarid grassland) using open-top chambers (OTCs). The relationship between the Nmass of these four Stipa species and precipitation well fits a logarithmic function. The sensitivity of these four species to precipitation change was ranked as follows: S. bungeana > S. breviflora > S. baicalensis > S. grandis. The Nmass of S. bungeana was the most sensitive to precipitation change, while S. grandis was the least sensitive among these Stipa species. Elevated CO2 exacerbated the effect of precipitation on Nmass. Nmass decreased under elevated CO2 due to growth dilution and a direct negative effect on N assimilation. Elevated CO2 reduced Nmass only in a certain precipitation range for S. baicalensis (163-343 mm), S. bungeana (164-355 mm), S. grandis (148-286 mm), and S. breviflora (130-316 mm); severe drought or excessive rainfall would be expected to result in a reduced impact of elevated CO2. Elevated CO2 affected the Nmass of S. grandis only in a narrow precipitation range. The effect of elevated CO2 reached a maximum when the amount of precipitation was 253, 260, 217, and 222 mm for S. baicalensis, S. bungeana, S. grandis, and S. breviflora, respectively. The Nmass of S. grandis was the least sensitive to elevated CO2. The Nmass of S. breviflora was more sensitive to elevated CO2 under a drought condition compared with the other Stipa species.

  14. CO2, Temperature, and Soil Moisture Interactions Affect NDVI and Reproductive Phenology in Old-Field Plant Communities

    NASA Astrophysics Data System (ADS)

    Engel, C.; Weltzin, J.; Norby, R.

    2004-12-01

    Plant community composition and ecosystem function may be altered by global atmospheric and climate change, including increased atmospheric [CO2], temperature, and varying precipitation regimes. We are conducting an experiment at Oak Ridge National Laboratory (ORNL) utilizing open-top chambers to administer experimental treatments of elevated CO2 (+300 ppm), warming (+ 3 degrees Celsius), and varying soil moisture availability to experimental plant communities constructed of seven common old-field species, including C3 and C4 grasses, forbs, and legumes. During 2004 we monitored plant community phenology (NDVI) and plant reproductive phenology. Early in the year, NDVI was greater in wet treatment plots, and was unaffected by main effects of temperature or CO2. This result suggests that early in the season warming is insufficient to affect early canopy development. Differences in soil moisture sustained throughout the winter and into early spring may constitute an important control on early canopy greenup. Elevated CO2 alleviated detrimental effects of warming on NDVI, but only early in the season. As ambient temperatures increased, elevated temperatures negatively impacted NDVI only in the dry plots. Wetter conditions ameliorate the effects of warming on canopy greenness during the warmer seasons of the year. Warming increased rates of bolting, number of inflorescences, and time to reproductive maturity for Andropogon virginicus (a C4 bunchgrass). Solidago Canadensis (a C3 late-season forb) also produced flowers earlier in elevated temperatures. Conversely, none of the C3 grasses and forbs that bolt or flower in late spring or early summer responded to temperature or CO2. Results indicate that warming and drought may impact plant community phenology, and plant species reproductive phenology. Clearly community phenology is driven by complex interactions among temperature, water, and CO2 that change throughout the season. Our data stresses the importance of

  15. Plant pollinator interactions: comparison between an invasive and a native congeneric species

    NASA Astrophysics Data System (ADS)

    Vanparys, Valérie; Meerts, Pierre; Jacquemart, Anne-Laure

    2008-11-01

    Plant-pollinator interactions determine reproductive success for animal-pollinated species and, in the case of invasive plants, they are supposed to play an important role in invasive success. We compared the invasive Senecio inaequidens to its native congener S. jacobaea in terms of interactions with pollinators. Visitor guild, visitation rate, and seed set were compared over 3 years in three sites in Belgium. Floral display (capitula number and arrangement) and phenology were quantified, and visiting insects were individually censused, i.e. number of visited capitula and time per visited capitulum. As expected from capitula resemblance, visitor guilds of both species were very similar (proportional similarity = 0.94). Senecio inaequidens was visited by 33 species, versus 36 for S. jacobaea. For both species, main visitors were Diptera, especially Syrphidae, and Hymenoptera. Visitation rate averaged 0.13 visitor per capitulum per 10 min for S. inaequidens against 0.08 for S. jacobaea. However, insects visited more capitula per plant on S. jacobaea, due to high capitula density (886 m -2 versus 206 m -2 for S. inaequidens), which is likely to increase self-pollen deposition considerably. Seed set of S. jacobaea was lower than that of S. inaequidens. We suggest that floral display is the major factor explaining the differences in insect visitation and seed set between the two Senecio species.

  16. Protein-protein interaction network-based detection of functionally similar proteins within species.

    PubMed

    Song, Baoxing; Wang, Fen; Guo, Yang; Sang, Qing; Liu, Min; Li, Dengyun; Fang, Wei; Zhang, Deli

    2012-07-01

    Although functionally similar proteins across species have been widely studied, functionally similar proteins within species showing low sequence similarity have not been examined in detail. Identification of these proteins is of significant importance for understanding biological functions, evolution of protein families, progression of co-evolution, and convergent evolution and others which cannot be obtained by detection of functionally similar proteins across species. Here, we explored a method of detecting functionally similar proteins within species based on graph theory. After denoting protein-protein interaction networks using graphs, we split the graphs into subgraphs using the 1-hop method. Proteins with functional similarities in a species were detected using a method of modified shortest path to compare these subgraphs and to find the eligible optimal results. Using seven protein-protein interaction networks and this method, some functionally similar proteins with low sequence similarity that cannot detected by sequence alignment were identified. By analyzing the results, we found that, sometimes, it is difficult to separate homologous from convergent evolution. Evaluation of the performance of our method by gene ontology term overlap showed that the precision of our method was excellent.

  17. Flow regime, temperature, and biotic interactions drive differential declines of trout species under climate change

    USGS Publications Warehouse

    Wenger, S.J.; Isaak, D.J.; Luce, C.H.; Neville, H.M.; Fausch, K.D.; Dunham, J.B.; Dauwalter, D.C.; Young, M.K.; Elsner, M.M.; Rieman, B.E.; Hamlet, A.F.; Williams, J.E.

    2011-01-01

    Broad-scale studies of climate change effects on freshwater species have focused mainly on temperature, ignoring critical drivers such as flow regime and biotic interactions. We use downscaled outputs from general circulation models coupled with a hydrologic model to forecast the effects of altered flows and increased temperatures on four interacting species of trout across the interior western United States (1.01 million km2), based on empirical statistical models built from fish surveys at 9,890 sites. Projections under the 2080s A1B emissions scenario forecast a mean 47% decline in total suitable habitat for all trout, a group of fishes of major socioeconomic and ecological significance. We project that native cutthroat trout Oncorhynchus clarkii, already excluded from much of its potential range by nonnative species, will lose a further 58% of habitat due to an increase in temperatures beyond the species' physiological optima and continued negative biotic interactions. Habitat for nonnative brook trout Salvelinus fontinalis and brown trout Salmo trutta is predicted to decline by 77% and 48%, respectively, driven by increases in temperature and winter flood frequency caused by warmer, rainier winters. Habitat for rainbow trout, Oncorhynchus mykiss, is projected to decline the least (35%) because negative temperature effects are partly offset by flow regime shifts that benefit the species. These results illustrate how drivers other than temperature influence species response to climate change. Despite some uncertainty, large declines in trout habitat are likely, but our findings point to opportunities for strategic targeting of mitigation efforts to appropriate stressors and locations.

  18. Flow regime, temperature, and biotic interactions drive differential declines of trout species under climate change.

    PubMed

    Wenger, Seth J; Isaak, Daniel J; Luce, Charles H; Neville, Helen M; Fausch, Kurt D; Dunham, Jason B; Dauwalter, Daniel C; Young, Michael K; Elsner, Marketa M; Rieman, Bruce E; Hamlet, Alan F; Williams, Jack E

    2011-08-23

    Broad-scale studies of climate change effects on freshwater species have focused mainly on temperature, ignoring critical drivers such as flow regime and biotic interactions. We use downscaled outputs from general circulation models coupled with a hydrologic model to forecast the effects of altered flows and increased temperatures on four interacting species of trout across the interior western United States (1.01 million km(2)), based on empirical statistical models built from fish surveys at 9,890 sites. Projections under the 2080s A1B emissions scenario forecast a mean 47% decline in total suitable habitat for all trout, a group of fishes of major socioeconomic and ecological significance. We project that native cutthroat trout Oncorhynchus clarkii, already excluded from much of its potential range by nonnative species, will lose a further 58% of habitat due to an increase in temperatures beyond the species' physiological optima and continued negative biotic interactions. Habitat for nonnative brook trout Salvelinus fontinalis and brown trout Salmo trutta is predicted to decline by 77% and 48%, respectively, driven by increases in temperature and winter flood frequency caused by warmer, rainier winters. Habitat for rainbow trout, Oncorhynchus mykiss, is projected to decline the least (35%) because negative temperature effects are partly offset by flow regime shifts that benefit the species. These results illustrate how drivers other than temperature influence species response to climate change. Despite some uncertainty, large declines in trout habitat are likely, but our findings point to opportunities for strategic targeting of mitigation efforts to appropriate stressors and locations.

  19. [Species specificity of fungi isolated from the affected rubber tires and their components].

    PubMed

    Chuienko, A I; Nakonechna, L T; Zhdanova, N M

    2010-01-01

    The mycobiota of the rubber technical wares, containing different plasticizers (natural and synthetic) have been investigated. Violation of production technology and storage conditions of the staggered rubber tires, caused their deterioration by the microfungi. Twenty seven (27) species of micromycetes, related to 16 genera were isolated from the surface and internal layers of such objects and their components. A number of species, which can exist theoretically on investigated rubber tires and their components, is calculated. The unfavorableness of the existence conditions for majority of fungi on such substrates is proved. The groups of species, which make the most contribution to deterioration of rubber tires and their components were revealed. These data were obtained using the methods of floristic analysis and computer processing of the data.

  20. Novel Genes Affecting the Interaction between the Cabbage Whitefly and Arabidopsis Uncovered by Genome-Wide Association Mapping.

    PubMed

    Broekgaarden, Colette; Bucher, Johan; Bac-Molenaar, Johanna; Keurentjes, Joost J B; Kruijer, Willem; Voorrips, Roeland E; Vosman, Ben

    2015-01-01

    Plants have evolved a variety of ways to defend themselves against biotic attackers. This has resulted in the presence of substantial variation in defense mechanisms among plants, even within a species. Genome-wide association (GWA) mapping is a useful tool to study the genetic architecture of traits, but has so far only had limited exploitation in studies of plant defense. Here, we study the genetic architecture of defense against the phloem-feeding insect cabbage whitefly (Aleyrodes proletella) in Arabidopsis thaliana. We determined whitefly performance, i.e. the survival and reproduction of whitefly females, on 360 worldwide selected natural accessions and subsequently performed GWA mapping using 214,051 SNPs. Substantial variation for whitefly adult survival and oviposition rate (number of eggs laid per female per day) was observed between the accessions. We identified 39 candidate SNPs for either whitefly adult survival or oviposition rate, all with relatively small effects, underpinning the complex architecture of defense traits. Among the corresponding candidate genes, i.e. genes in linkage disequilibrium (LD) with candidate SNPs, none have previously been identified as a gene playing a role in the interaction between plants and phloem-feeding insects. Whitefly performance on knock-out mutants of a number of candidate genes was significantly affected, validating the potential of GWA mapping for novel gene discovery in plant-insect interactions. Our results show that GWA analysis is a very useful tool to gain insight into the genetic architecture of plant defense against herbivorous insects, i.e. we identified and validated several genes affecting whitefly performance that have not previously been related to plant defense against herbivorous insects.

  1. Novel Genes Affecting the Interaction between the Cabbage Whitefly and Arabidopsis Uncovered by Genome-Wide Association Mapping

    PubMed Central

    Broekgaarden, Colette; Bucher, Johan; Bac-Molenaar, Johanna; Keurentjes, Joost J. B.; Kruijer, Willem; Voorrips, Roeland E.; Vosman, Ben

    2015-01-01

    Plants have evolved a variety of ways to defend themselves against biotic attackers. This has resulted in the presence of substantial variation in defense mechanisms among plants, even within a species. Genome-wide association (GWA) mapping is a useful tool to study the genetic architecture of traits, but has so far only had limited exploitation in studies of plant defense. Here, we study the genetic architecture of defense against the phloem-feeding insect cabbage whitefly (Aleyrodes proletella) in Arabidopsis thaliana. We determined whitefly performance, i.e. the survival and reproduction of whitefly females, on 360 worldwide selected natural accessions and subsequently performed GWA mapping using 214,051 SNPs. Substantial variation for whitefly adult survival and oviposition rate (number of eggs laid per female per day) was observed between the accessions. We identified 39 candidate SNPs for either whitefly adult survival or oviposition rate, all with relatively small effects, underpinning the complex architecture of defense traits. Among the corresponding candidate genes, i.e. genes in linkage disequilibrium (LD) with candidate SNPs, none have previously been identified as a gene playing a role in the interaction between plants and phloem-feeding insects. Whitefly performance on knock-out mutants of a number of candidate genes was significantly affected, validating the potential of GWA mapping for novel gene discovery in plant-insect interactions. Our results show that GWA analysis is a very useful tool to gain insight into the genetic architecture of plant defense against herbivorous insects, i.e. we identified and validated several genes affecting whitefly performance that have not previously been related to plant defense against herbivorous insects. PMID:26699853

  2. Imaging Imageability: Behavioral Effects and Neural Correlates of Its Interaction with Affect and Context

    PubMed Central

    Westbury, Chris F.; Cribben, Ivor; Cummine, Jacqueline

    2016-01-01

    The construct of imageability refers to the extent to which a word evokes a tangible sensation. Previous research (Westbury et al., 2013) suggests that the behavioral effects attributed to a word's imageability can be largely or wholly explained by two objective constructs, contextual density and estimated affect. Here, we extend these previous findings in two ways. First, we show that closely matched stimuli on the three measures of contextual density, estimated affect, and human-judged imageability show a three-way interaction in explaining variance in LD RTs, but that imagebility accounts for no additional variance after contextual density and estimated affect are entered first. Secondly, we demonstrate that the loci and functional connectivity (via graphical models) of the brain regions implicated in processing the three variables during that task are largely over-lapping and similar. These two lines of evidence support the conclusion that the effect usually attributed to human-judged imageability is largely or entirely due to the effects of other correlated measures that are directly computable. PMID:27471455

  3. Affect cues in vocalizations of the bat, Megaderma lyra, during agonistic interactions.

    PubMed

    Bastian, Anna; Schmidt, Sabine

    2008-07-01

    Some features of emotional prosody in human speech may be traced back to affect cues in mammalian vocalizations. The present study addresses the question whether affect intensity, as expressed by the intensity of behavioral displays, is encoded in vocal cues, i.e., changes in the structure of associated calls, in bats, a group evolutionarily remote from primates. A frame-by-frame video analysis of 109 dyadic agonistic interactions recorded in approach situations was performed to categorize displays into two intensity levels based on a cost-benefit estimate. M. lyra showed graded visual displays accompanied by specific calls and response calls of the second bat. A sound analysis revealed systematic changes of call sequence parameters with display level. At the high intensity level, total call duration, number of syllables within a call, and the number of calls within a sequence were increased, while intervals between call syllables were decreased for both call types. In addition, the latency of the response call was shorter, and its main syllable-type durations and fundamental frequency were increased. These systematic changes of vocal parameters with affect intensity correspond to prosodic changes in human speech, suggesting that emotion-related acoustic cues are a common feature of vocal communication in mammals.

  4. Potential Role of Elicitins in the Interaction between Phytophthora Species and Tobacco

    PubMed Central

    Kamoun, Sophien; Young, Mary; Förster, Helga; Coffey, Michael D.; Tyler, Brett M.

    1994-01-01

    The potential role of extracellular elicitor proteins (elicitins) from Phytophthora species as avirulence factors in the interaction between Phytophthora and tobacco was examined. A survey of 85 Phytophthora isolates representing 14 species indicated that production of elicitin is almost ubiquitous except for isolates of Phytophthora parasitica from tobacco. The production of elicitins by isolates of P. parasitica correlated without exception with low or no virulence on tobacco. Genetic analysis was conducted by using a cross between two isolat