Climate suitability and human influences combined explain the range expansion of an invasive horticultural plant

Treesearch

Carolyn M. Beans; Francis F. Kilkenny; Laura F. Galloway

2012-01-01

Ecological niche models are commonly used to identify regions at risk of species invasions. Relying on climate alone may limit a model's success when additional variables contribute to invasion. While a climate-based model may predict the future spread of an invasive plant, we hypothesized that a model that combined climate with human influences would most...

Testing basic ecological, evolutionary, and biogeographical principles using invasive species

Treesearch

Cynthia D. Huebner

2006-01-01

Sax et al. argue in Species Invasions: Insights into Ecology, Evolution, and Biogeography that species invasion is an on-going experiment and a research tool with which to test fundamental ecology, evolution, and biogeography tenets.

Invasion Ecology and School Biology--Part II.

ERIC Educational Resources Information Center

Wells, R. V.

1981-01-01

Suggests that invasion biology can supply subject matter for teaching evolution, genetics, ecological relationships, and conservation. Describes flowering and non-flowering plant invaders, vertebrates and invertebrates, and two ecological invasions on the southern coast of England. (JN)

Ecological risk assessment conceptual model formulation for nonindigenous species.

PubMed

Landis, Wayne G

2004-08-01

This article addresses the application of ecological risk assessment at the regional scale to the prediction of impacts due to invasive or nonindigenous species (NIS). The first section describes risk assessment, the decision-making process, and introduces regional risk assessment. A general conceptual model for the risk assessment of NIS is then presented based upon the regional risk assessment approach. Two diverse examples of the application of this approach are presented. The first example is based upon the dynamics of introduced plasmids into bacteria populations. The second example is the application risk assessment approach to the invasion of a coastal marine site of Cherry Point, Washington, USA by the European green crab. The lessons learned from the two examples demonstrate that assessment of the risks of invasion of NIS will have to incorporate not only the characteristics of the invasive species, but also the other stresses and impacts affecting the region of interest.

The ecological impact of invasive cane toads on tropical snakes: field data do not support laboratory-based predictions.

PubMed

Brown, Gregory P; Phillips, Benjamin L; Shine, Richard

2011-02-01

Predicting which species will be affected by an invasive taxon is critical to developing conservation priorities, but this is a difficult task. A previous study on the impact of invasive cane toads (Bufo marinus) on Australian snakes attempted to predict vulnerability a priori based on the assumptions that any snake species that eats frogs, and is vulnerable to toad toxins, may be at risk from the toad invasion. We used time-series analyses to evaluate the accuracy of that prediction, based on >3600 standardized nocturnal surveys over a 138-month period on 12 species of snakes and lizards on a floodplain in the Australian wet-dry tropics, bracketing the arrival of cane toads at this site. Contrary to prediction, encounter rates with most species were unaffected by toad arrival, and some taxa predicted to be vulnerable to toads increased rather than declined (e.g., death adder Acanthophis praelongus; Children's python Antaresia childreni). Indirect positive effects of toad invasion (perhaps mediated by toad-induced mortality of predatory varanid lizards) and stochastic weather events outweighed effects of toad invasion for most snake species. Our study casts doubt on the ability of a priori desktop studies, or short-term field surveys, to predict or document the ecological impact of invasive species.

What can morphology tell us about ecology of four invasive goby species?

PubMed

Jakubčinová, K; Simonović, P; Števove, B; Čanak Atlagić, J; Kováč, V

2017-05-01

This study presents a detailed comparative analysis of external morphology of four of the most invasive goby species in Europe (round goby Neogobius melanostomus, bighead goby Ponticola kessleri, monkey goby Neogobius fluviatilis and racer goby Ponticola gymnotrachelus) and interprets some ecological requirements of these species based on their morphological attributes. The results are evaluated within an ontogenetic context, and the morphological differences between the species are discussed in terms of the question: can special external shape adaptations help to assess the invasive potential of each species? The morphometric analyses demonstrate important differences between the four invasive gobies. Neogobius melanostomus appears to have the least specialized external morphology that may favour its invasive success: little specialization to habitat or diet means reduced restraints on overall ecological requirements. The other three species were found to possess some morphological specializations (P. kessleri to large prey, N. fluviatilis to sandy habitats and P. gymnotrachelus to macrophytes), but none of these gobies have managed to colonize such large areas or to reach such overall abundances as N. melanostomus. © 2017 The Fisheries Society of the British Isles.

Ecology of forest insect invasions

Treesearch

E.G. Brockerhoff; A.M. Liebhold

2017-01-01

Forests in virtually all regions of the world are being affected by invasions of non-native insects. We conducted an in-depth review of the traits of successful invasive forest insects and the ecological processes involved in insect invasions across the universal invasion phases (transport and arrival, establishment, spread and impacts). Most forest insect invasions...

Conceptual frameworks and methods for advancing invasion ecology.

PubMed

Heger, Tina; Pahl, Anna T; Botta-Dukát, Zoltan; Gherardi, Francesca; Hoppe, Christina; Hoste, Ivan; Jax, Kurt; Lindström, Leena; Boets, Pieter; Haider, Sylvia; Kollmann, Johannes; Wittmann, Meike J; Jeschke, Jonathan M

2013-09-01

Invasion ecology has much advanced since its early beginnings. Nevertheless, explanation, prediction, and management of biological invasions remain difficult. We argue that progress in invasion research can be accelerated by, first, pointing out difficulties this field is currently facing and, second, looking for measures to overcome them. We see basic and applied research in invasion ecology confronted with difficulties arising from (A) societal issues, e.g., disparate perceptions of invasive species; (B) the peculiarity of the invasion process, e.g., its complexity and context dependency; and (C) the scientific methodology, e.g., imprecise hypotheses. To overcome these difficulties, we propose three key measures: (1) a checklist for definitions to encourage explicit definitions; (2) implementation of a hierarchy of hypotheses (HoH), where general hypotheses branch into specific and precisely testable hypotheses; and (3) platforms for improved communication. These measures may significantly increase conceptual clarity and enhance communication, thus advancing invasion ecology.

Niche conservatism and the invasive potential of the wild boar.

PubMed

Sales, Lilian Patrícia; Ribeiro, Bruno R; Hayward, Matt Warrington; Paglia, Adriano; Passamani, Marcelo; Loyola, Rafael

2017-09-01

Niche conservatism, i.e. the retention of a species' fundamental niche through evolutionary time, is cornerstone for biological invasion assessments. The fact that species tend to maintain their original climate niche allows predictive maps of invasion risk to anticipate potential invadable areas. Unravelling the mechanisms driving niche shifts can shed light on the management of invasive species. Here, we assessed niche shifts in one of the world's worst invasive species: the wild boar Sus scrofa. We also predicted potential invadable areas based on an ensemble of three ecological niche modelling methods, and evaluated the performance of models calibrated with native vs. pooled (native plus invaded) species records. By disentangling the drivers of change on the exotic wild boar population's niches, we found strong evidence for niche conservatism during biological invasion. Ecological niche models calibrated with both native and pooled range records predicted convergent areas. Also, observed niche shifts are mostly explained by niche unfilling, i.e. there are unoccupied areas in the exotic range where climate is analogous to the native range. Niche unfilling is expected as result of recent colonization and ongoing dispersal, and was potentially stronger for the Neotropics, where a recent wave of introductions for pig-farming and game-hunting has led to high wild boar population growth rates. The invasive potential of wild boar in the Neotropics is probably higher than in other regions, which has profound management implications if we are to prevent their invasion into species-rich areas, such as Amazonia, coupled with expansion of African swine fever and possibly great economic losses. Although the originally Eurasian-wide distribution suggests a pre-adaptation to a wide array of climates, the wild boar world-wide invasion does not exhibit evidence of niche evolution. The invasive potential of the wild boar therefore probably lies on the reproductive, dietary and morphological characteristics of this species, coupled with behavioural thermoregulation. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Establishing Research and Management Priorities for Invasive Water Primroses (Ludwigia spp.)

DTIC Science & Technology

2016-02-01

among the most aggressive aquatic invasive plant invaders in the world. These aquatic Ludwigia species can impart severe ecological , economic, and...global trade and projected climate change. This technical report presents an overview of the biology and ecology of these invasive plant species, along...primrose species, like other invasive plants , must be grounded in basic knowledge of the biology and ecology of the species and their responses to

Invasive Species as Ecological Threat: Is Restoration an Alternative to Fear-based Resource Management?

Treesearch

Paul H. Gobster

2005-01-01

Invasive species is a hot topic in the USDA Forest Service these days. Along with wildfire, land conversion and unmanaged recreation, Chief Dale Bosworth has called invasive species one of the `Four Threats` needing the attention of Forest Service land managers and researchers (USDA Forest Service 2004). My unit of the Forest Service, the North Central Research...

Exploring the dynamics of research collaborations by mapping social networks in invasion science.

PubMed

Abrahams, B; Sitas, N; Esler, K J

2018-06-19

Moving towards more integrative approaches within the invasion sciences has been recognized as a means of improving linkages between science, policy, and practice. Yet despite the recognition that biological invasions pose complex social-ecological challenges, the invasion literature poorly covers social-ecological or distinctly integrative research. Various initiatives and investments have been made towards building research capacity and conducting more integrative research aimed at improving the management of biological invasions. Using a combination of social network and thematic analysis approaches, and the South African Working for Water (WfW) program as a case study for the management of invasive species, we identify and explore the roles of core authors in shaping collaboration networks and research outputs, based on bibliographic records. We found that research produced under the auspices of WfW is authored by a handful of core authors, conducting primarily ecologically-focused research, with social research significantly underrepresented. Core authors identified in this study play an essential role in mediating relationships between researchers, in addition to potentially controlling access to those seeking to form collaborations, maintaining network cohesion and connectivity across institutional and disciplinary boundaries. Research projects should be designed to span disciplines and institutions if they are to adequately address complex challenges. Copyright © 2018 Elsevier Ltd. All rights reserved.

A unified approach for quantifying invasibility and degree of invasion

Treesearch

Qinfeng Guo; Songlin Fei; Jeffrey S. Dukes; Christopher M. Oswalt; Basil V. Iannone III; Kevin M. Potter

2015-01-01

Habitat invasibility is a central focus of invasion biology, with implications for basic ecological patterns and processes and for effective invasion management. ‘‘Invasibility’’ is, however, one of the most elusive metrics and misused terms in ecology. Empirical studies and meta-analyses of invasibility have produced inconsistent and even conflicting results. This ...

Metabolite profiling of fish skin mucus: a novel approach for minimally-invasive environmental exposure monitoring and surveillance

EPA Science Inventory

The application of 'omics tools to biologically based monitoring and surveillance of aquatic environments shows considerable promise for complementing chemical monitoring in ecological risk assessments. However, few of the current approaches offer the ability to sample ecological...

A landscape approach for ecologically based management of Great Basin shrublands

Treesearch

Michael J. Wisdom; Jeanne C. Chambers

2009-01-01

Native shrublands dominate the Great Basin of western of North America, and most of these communities are at moderate or high risk of loss from non-native grass invasion and woodland expansion. Landscape-scale management based on differences in ecological resistance and resilience of shrublands can reduce these risks. We demonstrate this approach with an example that...

The ecological niche and reciprocal prediction of the disjunct distribution of an invasive species: the example of Ailanthus altissima

Treesearch

Thomas P. Albright; Hao Chen; Lijun Chen; Qinfeng Guo

2010-01-01

Knowledge of the ecological niches of invasive species in native and introduced ranges can inform management as well as ecological and evolutionary theory. Here, we identified and compared factors associated with the distribution of an invasive tree, Ailanthus altissima, in both its native Chinese and introduced US ranges and predicted potential US...

Doublethink and scale mismatch polarize policies for an invasive tree

PubMed Central

Roberts, Caleb P.; Uden, Daniel R.; Allen, Craig R.; Twidwell, Dirac

2018-01-01

Mismatches between invasive species management policies and ecological knowledge can lead to profound societal consequences. For this reason, natural resource agencies have adopted the scientifically-based density-impact invasive species curve to guide invasive species management. We use the density-impact model to evaluate how well management policies for a native invader (Juniperus virginiana) match scientific guidelines. Juniperus virginiana invasion is causing a sub-continental regime shift from grasslands to woodlands in central North America, and its impacts span collapses in endemic diversity, heightened wildfire risk, and crashes in grazing land profitability. We (1) use land cover data to identify the stage of Juniperus virginiana invasion for three ecoregions within Nebraska, USA, (2) determine the range of invasion stages at individual land parcel extents within each ecoregion based on the density-impact model, and (3) determine policy alignment and mismatches relative to the density-impact model in order to assess their potential to meet sustainability targets and avoid societal impacts as Juniperus virginiana abundance increases. We found that nearly all policies evidenced doublethink and policy-ecology mismatches, for instance, promoting spread of Juniperus virginiana regardless of invasion stage while simultaneously managing it as a native invader in the same ecoregion. Like other invasive species, theory and literature for this native invader indicate that the consequences of invasion are unlikely to be prevented if policies fail to prioritize management at incipient invasion stages. Theory suggests a more realistic approach would be to align policy with the stage of invasion at local and ecoregion management scales. There is a need for scientists, policy makers, and ecosystem managers to move past ideologies governing native versus non-native invader classification and toward a framework that accounts for the uniqueness of native species invasions, their anthropogenic drivers, and their impacts on ecosystem services. PMID:29513675

Estimating suitable environments for invasive plant species across large landscapes: A remote sensing strategy using Landsat 7 ETM+

USDA-ARS?s Scientific Manuscript database

The key to reducing ecological and economic damage caused by invasive plant species is to locate and eradicate new invasions before they threaten native biodiversity and ecological processes. We used Landsat Enhanced Thematic Mapper Plus imagery to estimate suitable environments for four invasive pl...

Parasites and marine invasions: Ecological and evolutionary perspectives

NASA Astrophysics Data System (ADS)

Goedknegt, M. Anouk; Feis, Marieke E.; Wegner, K. Mathias; Luttikhuizen, Pieternella C.; Buschbaum, Christian; Camphuysen, Kees (C. J.); van der Meer, Jaap; Thieltges, David W.

2016-07-01

Worldwide, marine and coastal ecosystems are heavily invaded by introduced species and the potential role of parasites in the success and impact of marine invasions has been increasingly recognized. In this review, we link recent theoretical developments in invasion ecology with empirical studies from marine ecosystems in order to provide a conceptual framework for studying the role of parasites and their hosts in marine invasions. Based on an extensive literature search, we identified six mechanisms in which invaders directly or indirectly affect parasite and host populations and communities: I) invaders can lose some or all of their parasites during the invasion process (parasite release or reduction), often causing a competitive advantage over native species; II) invaders can also act as a host for native parasites, which may indirectly amplify the parasite load of native hosts (parasite spillback); III) invaders can also be parasites themselves and be introduced without needing co-introduction of the host (introduction of free-living infective stages); IV) alternatively, parasites may be introduced together with their hosts (parasite co-introduction with host); V) consequently, these co-introduced parasites can sometimes also infect native hosts (parasite spillover); and VI) invasive species may be neither a host nor a parasite, but nevertheless affect native parasite host interactions by interfering with parasite transmission (transmission interference). We discuss the ecological and evolutionary implications of each of these mechanisms and generally note several substantial effects on natural communities and ecosystems via i) mass mortalities of native populations creating strong selection gradients, ii) indirect changes in species interactions within communities and iii) trophic cascading and knock-on effects in food webs that may affect ecosystem function and services. Our review demonstrates a wide range of ecological and evolutionary implications of marine invasions for parasite-host interactions and suggests that parasite-mediated impacts should be integrated in assessing the risks and consequences of biological invasions.

Go forth, evolve and prosper: the genetic basis of adaptive evolution in an invasive species.

PubMed

Franks, Steven J; Munshi-South, Jason

2014-05-01

Invasive species stand accused of a familiar litany of offences, including displacing native species, disrupting ecological processes and causing billions of dollars in ecological damage (Cox 1999). Despite these transgressions, invasive species have at least one redeeming virtue--they offer us an unparalleled opportunity to investigate colonization and responses of populations to novel conditions in the invaded habitat (Elton 1958; Sakai et al. 2001). Invasive species are by definition colonists that have arrived and thrived in a new location. How they are able to thrive is of great interest, especially considering a paradox of invasion (Sax & Brown 2000): if many populations are locally adapted (Leimu & Fischer 2008), how could species introduced into new locations become so successful? One possibility is that populations adjust to the new conditions through plasticity--increasing production of allelopathic compounds (novel weapons), or taking advantage of new prey, for example. Alternatively, evolution could play a role, with the populations adapting to the novel conditions of the new habitat. There is increasing evidence, based on phenotypic data, for rapid adaptive evolution in invasive species (Franks et al. 2012; Colautti & Barrett 2013; Sultan et al. 2013). Prior studies have also demonstrated genetic changes in introduced populations using neutral markers, which generally do not provide information on adaptation. Thus, the genetic basis of adaptive evolution in invasive species has largely remained unknown. In this issue of Molecular Ecology, Vandepitte et al. (2014) provide some of the first evidence in invasive populations for molecular genetic changes directly linked to adaptation. © 2014 John Wiley & Sons Ltd.

Rapid evolution mitigates the ecological consequences of an invasive species (Bythotrephes longimanus) in lakes in Wisconsin.

PubMed

Gillis, Michael K; Walsh, Matthew R

2017-07-12

Invasive species have extensive negative consequences for biodiversity and ecosystem health. Novel species also drive contemporary evolution in many native populations, which could mitigate or amplify their impacts on ecosystems. The predatory zooplankton Bythotrephes longimanus invaded lakes in Wisconsin, USA, in 2009. This invasion caused precipitous declines in zooplankton prey ( Daphnia pulicaria ), with cascading impacts on ecosystem services (water clarity). Here, we tested the link between Bythotrephes invasion, evolution in Daphnia and post-invasion ecological dynamics using 15 years of long-term data in conjunction with comparative experiments. Invasion by Bythotrephes is associated with rapid increases in the body size of Daphnia Laboratory experiments revealed that such shifts have a genetic component; third-generation laboratory-reared Daphnia from 'invaded' lakes are significantly larger and exhibit greater reproductive effort than individuals from 'uninvaded' lakes. This trajectory of evolution should accelerate Daphnia population growth and enhance population persistence. We tested this prediction by comparing analyses of long-term data with laboratory-based simulations, and show that rapid evolution in Daphnia is associated with increased population growth in invaded lakes. © 2017 The Authors.

INVASIVE SPECIES: PREDICTING GEOGRAPHIC DISTRIBUTIONS USING ECOLOGICAL NICHE MODELING

EPA Science Inventory

Present approaches to species invasions are reactive in nature. This scenario results in management that perpetually lags behind the most recent invasion and makes control much more difficult. In contrast, spatially explicit ecological niche modeling provides an effective solut...

Cross-Attraction between an Exotic and a Native Pine Bark Beetle: A Novel Invasion Mechanism?.

Treesearch

Min Lu; Daniel Miller; Jiang-Hua Sun

2007-01-01

Aside from the ecological impacts, invasive species fascinate ecologists because of the unique opportunities that invasives offer in the study of community ecology. Some hypotheses have been proposed to illustrate the mechanisms that allow exotics to become invasive. However, positive interactions between exotic and native insects are rarely utilized to explain...

Cross-attraction between an exotic and a native pine bark beetle: a novel invasion mechanism?

Treesearch

Min Lu; Daniel R. Miller; Jiang-Hua Sun

2007-01-01

Aside from the ecological impacts, invasive species fascinate ecologists because of the unique opportunities that invasives offer in the study of community ecology. Some hypotheses have been proposed to illustrate the mechanisms that allow exotics to become invasive. However, positive interactions between exotic and native insects are rarely utilized to explain...

Allelochemical Control of Non-Indigenous Invasive Plant Species Affecting Military Testing and Training Activities

DTIC Science & Technology

2010-10-01

Evolution in invasive plants : implications for biological control. Trends in Ecology & Evolution . 19:417-422. Newingham, B.A. and R.M. Callaway...2008. Soil ecological interactions of spotted knapweed and native plant species. M.S. Thesis. Colorado State University. Fort Collins, CO...weapons and exotic plant invasions. NSF workshop on ecology and biochemical interactions , Lima. Peru. May. Keynote presentation. Callaway, R.M

A Bosque Riparian Community Index Model for the Middle Rio Grande, Albuquerque, New Mexico: Model Documentation

DTIC Science & Technology

2012-09-01

ecological processes involve the invasion of non-native (exotic) species (USEPA 1999). Through direct biotic interactions (predation and competition) and...indirect interactions ( ecological engineering and habitat modification), invasive species can disrupt the natural population dynamics of native...species (USEPA 1999). Invasives can include noxious plants (i.e., plants that are listed by a state because of their unfavorable economic or ecological

[The vegetation adventivisation through perspective of modern ecological ideas].

PubMed

Mirkin, B M; Naumova, L G

2002-01-01

Results of study of vegetation adventivisation (increase in proportion of invasive species) correspond to the theory of present ecology that denies general universal laws. Diverse features of invasive species play different role under various ecological conditions and at various time and space scale. The invasibility of communities under various conditions is determined by combination of different biotic and abiotic factors though it is obvious that most of invasive species are characterized with the high seed production, well developed vegetative propagation, windblown pollination, high plasticity and effective use of resources, low consumption by herbivores. The definition of an "ideal invasive species" or an "ideal invasible community" is impossible. The regularities of vegetation adventivisation can be observed clearly only at very large scale.

Evidence of niche shift and invasion potential of Lithobates catesbeianus in the habitat of Mexican endemic frogs

PubMed Central

Becerra López, Jorge Luis; Romero Méndez, Ulises; Sigala Rodríguez, José Jesús; Mayer Goyenechea, Irene Goyenechea; Castillo Cerón, Jesús Martín

2017-01-01

Invasive alien species are one of most severe threats to biodiversity and natural resources. These biological invasions have been studied from the niche conservatism and niche shifts perspective. Niche differentiation may result from changes in fundamental niche or realized niche or both; in biological invasions, niche differences between native and non-native ranges can appear through niche expansion, niche unfilling and niche stability. The American bullfrog Lithobates catesbeianus is an invasive species that can have negative impacts on native amphibian populations. This research examines the climate niche shifts of this frog, its potential range of expansion in Mexico and the risk of invasion by bullfrog in the habitats of 82 frog species endemic to Mexico, that based on their climatic niche similarity were divided in four ecological groups. The results indicate that species in two ecological groups were the most vulnerable to invasion by bullfrog. However, the climate niche shifts of L. catesbeianus may allow it to adapt to new environmental conditions, so species from the two remaining groups cannot be dismissed as not vulnerable. This information is valuable for decision making in prioritizing areas for conservation of Mexican endemic frogs. PMID:28953907

Evidence of niche shift and invasion potential of Lithobates catesbeianus in the habitat of Mexican endemic frogs.

PubMed

Becerra López, Jorge Luis; Esparza Estrada, Citlalli Edith; Romero Méndez, Ulises; Sigala Rodríguez, José Jesús; Mayer Goyenechea, Irene Goyenechea; Castillo Cerón, Jesús Martín

2017-01-01

Invasive alien species are one of most severe threats to biodiversity and natural resources. These biological invasions have been studied from the niche conservatism and niche shifts perspective. Niche differentiation may result from changes in fundamental niche or realized niche or both; in biological invasions, niche differences between native and non-native ranges can appear through niche expansion, niche unfilling and niche stability. The American bullfrog Lithobates catesbeianus is an invasive species that can have negative impacts on native amphibian populations. This research examines the climate niche shifts of this frog, its potential range of expansion in Mexico and the risk of invasion by bullfrog in the habitats of 82 frog species endemic to Mexico, that based on their climatic niche similarity were divided in four ecological groups. The results indicate that species in two ecological groups were the most vulnerable to invasion by bullfrog. However, the climate niche shifts of L. catesbeianus may allow it to adapt to new environmental conditions, so species from the two remaining groups cannot be dismissed as not vulnerable. This information is valuable for decision making in prioritizing areas for conservation of Mexican endemic frogs.

Ecosystem and immune systems: Hierarchial response provides resilience against invasions

USGS Publications Warehouse

Allen, Craig R.

2001-01-01

Janssen (2001) provides the stimulus for thoughtful comparison and consideration of the ranges of responses exhibited by immune systems and ecological systems in the face of perturbations such as biological invasions. It may indeed be informative to consider the similarities of the responses to invasions exhibited by immune systems and ecological systems. Clearly, both types of systems share a general organizational structure with all other complex hierarchical systems. Their organization provides these systems with resilience. However, when describing the response of ecological-economic systems to invasions, Janssen emphasizes the human-economic response. I would like to expand on his comparison by focusing on how resilience is maintained in complex systems under the threat of invasion.

The complexity underlying invasiveness precludes the identification of invasive traits: A comparative study of invasive and non-invasive heterocarpic Atriplex congeners

PubMed Central

Doudová, Jana; Douda, Jan; Mandák, Bohumil

2017-01-01

Heterocarpy enables species to effectively spread under unfavourable conditions by producing two or more types of fruit differing in ecological characteristics. Although it is frequent in annuals occupying disturbed habitats that are vulnerable to invasion, there is still a lack of congeneric studies addressing the importance of heterocarpy for species invasion success. We compared two pairs of heterocarpic Atriplex species, each of them comprising one invasive and one non-invasive non-native congener. In two common garden experiments, we (i) simulated the influence of different levels of nutrients and population density on plants grown from different types of fruits and examined several traits that are generally positively associated with invasion success, and (ii) grew plants in a replacement series experiment to evaluate resource partitioning between them and to compare their competitive ability. We found that specific functional traits or competitiveness of species cannot explain the invasiveness of Atriplex species, indicating that species invasiveness involves more complex interactions of traits that are important only in certain ecological contexts, i.e. in specific environmental conditions and only some habitats. Interestingly, species trait differences related to invasion success were found between plants growing from the ecologically most contrasting fruit types. We suggest that fruit types differing in ecological behaviour may be essential in the process of invasion or in the general spreading of heterocarpic species, as they either the maximize population growth (type C fruit) or enhance the chance of survival of new populations (type A fruit). Congeners offer the best available methodical framework for comparing traits among phylogenetically closely related invasive and non-invasive species. However, as indicated by our results, this approach is unlikely to reveal invasive traits because of the complexity underlying invasiveness. PMID:28445514

Are local filters blind to provenance? Ant seed predation suppresses exotic plants more than natives

Treesearch

Dean E. Pearson; Nadia S. Icasatti; Jose L. Hierro; Benjamin J. Bird

2014-01-01

The question of whether species' origins influence invasion outcomes has been a point of substantial debate in invasion ecology. Theoretically, colonization outcomes can be predicted based on how species' traits interact with community filters, a process presumably blind to species' origins. Yet, exotic plant introductions commonly result in monospecific...

Predicting the spatial distribution of Lonicera japonica, based on species occurrence data from two watersheds in Western Kentucky and Tennessee

Treesearch

Dongjiao Liu; Hao Jiang; Robin Zhang; Kate S. He

2011-01-01

The spatial distribution of most invasive plants is poorly documented and studied. This project examined and compared the spatial distribution of a successful invasive plant, Japanese honeysuckle (Lonicera japonica), in two similar-sized but ecologically distinct watersheds in western Kentucky (Ledbetter Creek) and western Tennessee (Panther Creek)....

Effectiveness of Selected Native Plants as Competitors with Non-indigenous and Invasive Knapweed and Thistle Species

DTIC Science & Technology

2011-09-01

M. Wolfe. 2004. The evolution of an invasive plant : An experimental study with Silene latifolia. Ecology 85(11):3035-42. Blossey, B., and R...Notzold. 1995. Evolution of increased competitive ability in invasive nonindigenous plants : A hypothesis. Journal of Ecology 83(5):887-9. Bottoms, R. M... interactions between salt marsh plants : Effects of salinity, sediment and waterlogging. Journal of Ecology 88(3):492-505. Hyder, S. Z., and S. Yasmin

Comparison of Four Sampling Gears to Collect Invasive Benthic Invertebrates in the St. Louis Harbor, Duluth, MN

EPA Science Inventory

Invasive and non-indigenous species have become an increasing concern throughout the world, because of their ecological and economic impacts. In the Great Lakes, they have been linked to major ecological shifts, and millions of dollars in economic expenses. Invasive species hav...

Doublethink and scale mismatch polarize policies for an invasive tree

USGS Publications Warehouse

Roberts, Caleb P.; Uden, Daniel R.; Allen, Craig R.; Twidwell, Dirac

2018-01-01

Mismatches between invasive species management policies and ecological knowledge can lead to profound societal consequences. For this reason, natural resource agencies have adopted the scientifically-based density-impact invasive species curve to guide invasive species management. We use the density-impact model to evaluate how well management policies for a native invader (Juniperus virginiana) match scientific guidelines. Juniperus virginiana invasion is causing a sub-continental regime shift from grasslands to woodlands in central North America, and its impacts span collapses in endemic diversity, heightened wildfire risk, and crashes in grazing land profitability. We (1) use land cover data to identify the stage of Juniperus virginiana invasion for three ecoregions within Nebraska, USA, (2) determine the range of invasion stages at individual land parcel extents within each ecoregion based on the density-impact model, and (3) determine policy alignment and mismatches relative to the density-impact model in order to assess their potential to meet sustainability targets and avoid societal impacts as Juniperus virginiana abundance increases. We found that nearly all policies evidenced doublethink and policy-ecology mismatches, for instance, promoting spread of Juniperus virginiana regardless of invasion stage while simultaneously managing it as a native invader in the same ecoregion. Like other invasive species, theory and literature for this native invader indicate that the consequences of invasion are unlikely to be prevented if policies fail to prioritize management at incipient invasion stages. Theory suggests a more realistic approach would be to align policy with the stage of invasion at local and ecoregion management scales. There is a need for scientists, policy makers, and ecosystem managers to move past ideologies governing native versus non-native invader classification and toward a framework that accounts for the uniqueness of native species invasions, their anthropogenic drivers, and their impacts on ecosystem services.

Biological Invasions: A Challenge In Ecological Forecasting

NASA Technical Reports Server (NTRS)

Schnase, J. L.; Smith, J. A.; Stohlgren, T. J.; Graves, S.; Trees, C.; Rood, Richard (Technical Monitor)

2002-01-01

The spread of invasive species is one of the most daunting environmental, economic, and human-health problems facing the United States and the World today. It is one of several grand challenge environmental problems being considered by NASA's Earth Science Vision for 2025. The invasive species problem is complex and presents many challenges. Developing an invasive species predictive capability could significantly advance the science and technology of ecological forecasting.

The ecology of forest insect invasions and advances in their management

Treesearch

Eckehard G. Brockerhoff; Andrew M. Liebhold; Herv& #233; Jactel

2006-01-01

Invasions by nonindigenous forest insects can have spectacular effects on the biodiversity, ecology, and economy of affected areas. This introduction explores several critical issues that are generally relevant to invasions by forest insects to provide an extended background for this special issue of the Canadian Journal of Forest Research and...

Landowners' Perspectives on Coordinated, Landscape-Level Invasive Species Control: The Role of Social and Ecological Context.

PubMed

Niemiec, Rebecca M; Pech, Roger P; Norbury, Grant L; Byrom, Andrea E

2017-03-01

To achieve biodiversity gains, landowner engagement in coordinated invasive species control programs across private lands is needed. Understanding landowners' perspectives toward such coordinated control efforts is crucial to facilitating engagement. We conducted in person and mail surveys of 68 landowners in and adjacent to the area of a proposed invasive predator control program in New Zealand. We find that, similar to previous studies, landowners consider the potential socioeconomic and ecological benefits of invasive species control and express a strong desire to enhance native biodiversity. However, we also find that landowners take into account the complexity of the local social and ecological context in which a program will unfold in three ways: they consider (1) the level of contribution by other landowners and urban residents who are benefiting from collective control efforts; (2) the potential for the program to upset the local "ecological balance", leading to increases in other pests; and (3) the probability that the program will be successful given the likelihood of others participating and control tactics being effective. We suggest that managers of coordinated invasive species control efforts may benefit from devoting time and resources toward addressing beliefs about social and ecological context, rather than solely providing financial subsidies and information about control tactics or the impacts of invasive species.

Landowners' Perspectives on Coordinated, Landscape-Level Invasive Species Control: The Role of Social and Ecological Context

NASA Astrophysics Data System (ADS)

Niemiec, Rebecca M.; Pech, Roger P.; Norbury, Grant L.; Byrom, Andrea E.

2017-03-01

To achieve biodiversity gains, landowner engagement in coordinated invasive species control programs across private lands is needed. Understanding landowners' perspectives toward such coordinated control efforts is crucial to facilitating engagement. We conducted in person and mail surveys of 68 landowners in and adjacent to the area of a proposed invasive predator control program in New Zealand. We find that, similar to previous studies, landowners consider the potential socioeconomic and ecological benefits of invasive species control and express a strong desire to enhance native biodiversity. However, we also find that landowners take into account the complexity of the local social and ecological context in which a program will unfold in three ways: they consider (1) the level of contribution by other landowners and urban residents who are benefiting from collective control efforts; (2) the potential for the program to upset the local "ecological balance", leading to increases in other pests; and (3) the probability that the program will be successful given the likelihood of others participating and control tactics being effective. We suggest that managers of coordinated invasive species control efforts may benefit from devoting time and resources toward addressing beliefs about social and ecological context, rather than solely providing financial subsidies and information about control tactics or the impacts of invasive species.

Multi level ecological fitting: indirect life cycles are not a barrier to host switching and invasion.

PubMed

Malcicka, Miriama; Agosta, Salvatore J; Harvey, Jeffrey A

2015-09-01

Many invasive species are able to escape from coevolved enemies and thus enjoy a competitive advantage over native species. However, during the invasion phase, non-native species must overcome many ecological and/or physiological hurdles before they become established and spread in their new habitats. This may explain why most introduced species either fail to establish or remain as rare interstitials in their new ranges. Studies focusing on invasive species have been based on plants or animals where establishment requires the possession of preadapted traits from their native ranges that enables them to establish and spread in their new habitats. The possession of preadapted traits that facilitate the exploitation of novel resources or to colonize novel habitats is known as 'ecological fitting'. Some species have evolved traits and life histories that reflect highly intimate associations with very specific types of habitats or niches. For these species, their phenological windows are narrow, and thus the ability to colonize non-native habitats requires that a number of conditions need to be met in accordance with their more specialized life histories. Some of the strongest examples of more complex ecological fitting involve invasive parasites that require different animal hosts to complete their life cycles. For instance, the giant liver fluke, Fascioloides magna, is a major parasite of several species of ungulates in North America. The species exhibits a life cycle whereby newly hatched larvae must find suitable intermediate hosts (freshwater snails) and mature larvae, definitive hosts (ungulates). Intermediate and definitive host ranges of F. magna in its native range are low in number, yet this parasite has been successfully introduced into Europe where it has become a parasite of native European snails and deer. We discuss how the ability of these parasites to overcome multiple ecophysiological barriers represents an excellent example of 'multiple-level ecological fitting'. © 2015 John Wiley & Sons Ltd.

Making Invasion models useful for decision makers; incorporating uncertainty, knowledge gaps, and decision-making preferences

Treesearch

Denys Yemshanov; Frank H Koch; Mark Ducey

2015-01-01

Uncertainty is inherent in model-based forecasts of ecological invasions. In this chapter, we explore how the perceptions of that uncertainty can be incorporated into the pest risk assessment process. Uncertainty changes a decision maker’s perceptions of risk; therefore, the direct incorporation of uncertainty may provide a more appropriate depiction of risk. Our...

Invasions and extinctions through the looking glass of evolutionary ecology

PubMed Central

2017-01-01

Invasive and endangered species reflect opposite ends of a spectrum of ecological success, yet they experience many similar eco-evolutionary challenges including demographic bottlenecks, hybridization and novel environments. Despite these similarities, important differences exist. Demographic bottlenecks are more transient in invasive species, which (i) maintains ecologically relevant genetic variation, (ii) reduces mutation load, and (iii) increases the efficiency of natural selection relative to genetic drift. Endangered species are less likely to benefit from admixture, which offsets mutation load but also reduces fitness when populations are locally adapted. Invading species generally experience more benign environments with fewer natural enemies, which increases fitness directly and also indirectly by masking inbreeding depression. Adaptive phenotypic plasticity can maintain fitness in novel environments but is more likely to evolve in invasive species encountering variable habitats and to be compromised by demographic factors in endangered species. Placed in an eco-evolutionary context, these differences affect the breadth of the ecological niche, which arises as an emergent property of antagonistic selection and genetic constraints. Comparative studies of invasions and extinctions that apply an eco-evolutionary perspective could provide new insights into the environmental and genetic basis of ecological success in novel environments and improve efforts to preserve global biodiversity. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’. PMID:27920376

Dietary Flexibility Aids Asian Earthworm Invasion in North American Forests

EPA Science Inventory

On a local scale, invasiveness of introduced species and invasibility of habitats together determine invasion success. A key issue in invasion ecology has been how to quantify the contribution of species invasiveness and habitat invasibility separately. Conventional approaches, s...

When relationships estimated in the past cannot be used to predict the future: using mechanistic models to predict landscape ecological dynamics in a changing world

Treesearch

Eric J. Gustafson

2013-01-01

Researchers and natural resource managers need predictions of how multiple global changes (e.g., climate change, rising levels of air pollutants, exotic invasions) will affect landscape composition and ecosystem function. Ecological predictive models used for this purpose are constructed using either a mechanistic (process-based) or a phenomenological (empirical)...

When mechanism matters: Bayesian forecasting using models of ecological diffusion

USGS Publications Warehouse

Hefley, Trevor J.; Hooten, Mevin B.; Russell, Robin E.; Walsh, Daniel P.; Powell, James A.

2017-01-01

Ecological diffusion is a theory that can be used to understand and forecast spatio-temporal processes such as dispersal, invasion, and the spread of disease. Hierarchical Bayesian modelling provides a framework to make statistical inference and probabilistic forecasts, using mechanistic ecological models. To illustrate, we show how hierarchical Bayesian models of ecological diffusion can be implemented for large data sets that are distributed densely across space and time. The hierarchical Bayesian approach is used to understand and forecast the growth and geographic spread in the prevalence of chronic wasting disease in white-tailed deer (Odocoileus virginianus). We compare statistical inference and forecasts from our hierarchical Bayesian model to phenomenological regression-based methods that are commonly used to analyse spatial occurrence data. The mechanistic statistical model based on ecological diffusion led to important ecological insights, obviated a commonly ignored type of collinearity, and was the most accurate method for forecasting.

What do we really know about alien plant invasion? A review of the invasion mechanism of one of the world's worst weeds.

PubMed

Bajwa, Ali Ahsan; Chauhan, Bhagirath Singh; Farooq, Muhammad; Shabbir, Asad; Adkins, Steve William

2016-07-01

This review provides an insight into alien plant invasion taking into account the invasion mechanism of parthenium weed ( Parthenium hysterophorus L.). A multi-lateral understanding of the invasion biology of this weed has pragmatic implications for weed ecology and management. Biological invasions are one of the major drivers of restructuring and malfunctioning of ecosystems. Invasive plant species not only change the dynamics of species composition and biodiversity but also hinder the system productivity and efficiency in invaded regions. Parthenium weed, a well-known noxious invasive species, has invaded diverse climatic and biogeographic regions in more than 40 countries across five continents. Efforts are under way to minimize the parthenium weed-induced environmental, agricultural, social, and economic impacts. However, insufficient information regarding its invasion mechanism and interference with ecosystem stability is available. It is hard to devise effective management strategies without understanding the invasion process. Here, we reviewed the mechanism of parthenium weed invasion. Our main conclusions are: (1) morphological advantages, unique reproductive biology, competitive ability, escape from natural enemies in non-native regions, and a C3/C4 photosynthesis are all likely to be involved in parthenium weed invasiveness. (2) Tolerance to abiotic stresses and ability to grow in wide range of edaphic conditions are thought to be additional invasion tools on a physiological front. (3) An allelopathic potential of parthenium weed against crop, weed and pasture species, with multiple modes of allelochemical expression, may also be responsible for its invasion success. Moreover, the release of novel allelochemicals in non-native environments might have a pivotal role in parthenium weed invasion. (4) Genetic diversity found among different populations and biotypes of parthenium weed, based on geographic, edaphic, climatic, and ecological ranges, might also be a strong contributor towards its invasion success. (5) Rising temperatures and atmospheric carbon dioxide (CO2) concentrations and changing rainfall patterns, all within the present day climate change prediction range are favorable for parthenium weed growth, its reproductive output, and therefore its future spread and infestation. (6) Parthenium weed invasion in South Asia depicts the relative and overlapping contribution of all the above-mentioned mechanisms. Such an understanding of the core phenomena regulating the invasion biology has pragmatic implications for its management. A better understanding of the interaction of physiological processes, ecological functions, and genetic makeup within a range of environments may help to devise appropriate management strategies for parthenium weed.

Invasion of two tick-borne diseases across New England: harnessing human surveillance data to capture underlying ecological invasion processes

PubMed Central

Walter, Katharine S.; Pepin, Kim M.; Webb, Colleen T.; Gaff, Holly D.; Krause, Peter J.; Pitzer, Virginia E.; Diuk-Wasser, Maria A.

2016-01-01

Modelling the spatial spread of vector-borne zoonotic pathogens maintained in enzootic transmission cycles remains a major challenge. The best available spatio-temporal data on pathogen spread often take the form of human disease surveillance data. By applying a classic ecological approach—occupancy modelling—to an epidemiological question of disease spread, we used surveillance data to examine the latent ecological invasion of tick-borne pathogens. Over the last half-century, previously undescribed tick-borne pathogens including the agents of Lyme disease and human babesiosis have rapidly spread across the northeast United States. Despite their epidemiological importance, the mechanisms of tick-borne pathogen invasion and drivers underlying the distinct invasion trajectories of the co-vectored pathogens remain unresolved. Our approach allowed us to estimate the unobserved ecological processes underlying pathogen spread while accounting for imperfect detection of human cases. Our model predicts that tick-borne diseases spread in a diffusion-like manner with occasional long-distance dispersal and that babesiosis spread exhibits strong dependence on Lyme disease. PMID:27252022

Focusing ecological research for conservation.

PubMed

Cristescu, Bogdan; Boyce, Mark S

2013-11-01

Ecologists are increasingly actively involved in conservation. We identify five key topics from a broad sweep of ecology that merit research attention to meet conservation needs. We examine questions from landscape ecology, behavioral ecology, ecosystem dynamics, community ecology, and nutrient cycling related to key topics. Based on literature review and publication trend assessment, consultation with colleagues, and roundtable discussions at the 24th International Congress for Conservation Biology, focused research on the following topics could benefit conservation while advancing ecological understanding: 1. Carbon sequestration, requiring increased linkages to biodiversity conservation; 2. Ecological invasiveness, challenging our ability to find solutions to ecological aliens; 3. Individual variation, having applications in the conservation of rare species; 4. Movement of organisms, integrating ecological processes across landscapes and scales and addressing habitat fragmentation; and 5. Trophic-level interactions, driving ecological dynamics at the ecosystem-level. Addressing these will require cross-disciplinary research under the overarching framework of conservation ecology.

Different Traits Determine Introduction, Naturalization and Invasion Success In Woody Plants: Proteaceae as a Test Case

PubMed Central

Moodley, Desika; Geerts, Sjirk; Richardson, David M.; Wilson, John R. U.

2013-01-01

A major aim of invasion ecology is to identify characteristics of successful invaders. However, most plant groups studied in detail (e.g. pines and acacias) have a high percentage of invasive taxa. Here we examine the global introduction history and invasion ecology of Proteaceae—a large plant family with many taxa that have been widely disseminated by humans, but with few known invaders. To do this we compiled a global list of species and used boosted regression tree models to assess which factors are important in determining the status of a species (not introduced, introduced, naturalized or invasive). At least 402 of 1674 known species (24%) have been moved by humans out of their native ranges, 58 species (14%) have become naturalized but not invasive, and 8 species (2%) are invasive. The probability of naturalization was greatest for species with large native ranges, low susceptibility to Phytophthora root-rot fungus, large mammal-dispersed seeds, and with the capacity to resprout. The probability of naturalized species becoming invasive was greatest for species with large native ranges, those used as barrier plants, tall species, species with small seeds, and serotinous species. The traits driving invasiveness of Proteaceae were similar to those for acacias and pines. However, while some traits showed a consistent influence at introduction, naturalization and invasion, others appear to be influential at one stage only, and some have contrasting effects at different stages. Trait-based analyses therefore need to consider different invasion stages separately. On their own, these observations provide little predictive power for risk assessment, but when the causative mechanisms are understood (e.g. Phytophthora susceptibility) they provide valuable insights. As such there is considerable value in seeking the correlates and mechanisms underlying invasions for particular taxonomic or functional groups. PMID:24086442

Biological invasions, ecological resilience and adaptive governance

EPA Science Inventory

In a world of increasing interconnections in global trade as well as rapid change in climate and land cover, the accelerating introduction and spread of invasive species is a critical concern due to associated negative social and ecological impacts, both real and perceived. Much...

Invasive plant species in the West Indies: geographical, ecological, and floristic insights.

PubMed

Rojas-Sandoval, Julissa; Tremblay, Raymond L; Acevedo-Rodríguez, Pedro; Díaz-Soltero, Hilda

2017-07-01

The level of invasion (number or proportion of invasive species) in a given area depends on features of the invaded community, propagule pressure, and climate. In this study, we assess the invasive flora of nine islands in the West Indies to identify invasion patterns and evaluate whether invasive species diversity is related to geographical, ecological, and socioeconomic factors. We compiled a database of invasive plant species including information on their taxonomy, origin, pathways of introduction, habitats, and life history. This database was used to evaluate the similarity of invasive floras between islands and to identify invasion patterns at regional (West Indies) and local (island) scales. We found a total of 516 alien plant species that are invasive on at least one of the nine islands studied, with between 24 to 306 invasive species per island. The invasive flora on these islands includes a wide range of taxonomic groups, life forms, and habitats. We detected low similarity in invasive species diversity between islands, with most invasive species (>60%) occurring on a single island and 6% occurring on at least five islands. To assess the importance of different models in predicting patterns of invasive species diversity among islands, we used generalized linear models. Our analyses revealed that invasive species diversity was well predicted by a combination of island area and economic development (gross domestic product per capita and kilometers of paved roadways). Our results provide strong evidence for the roles of geographical, ecological, and socioeconomic factors in determining the distribution and spread of invasive species on these islands. Anthropogenic disturbance and economic development seem to be the major drivers facilitating the spread and predominance of invasive species over native species.

Conceptualising the interactive effects of climate change and biological invasions on subarctic freshwater fish.

PubMed

Rolls, Robert J; Hayden, Brian; Kahilainen, Kimmo K

2017-06-01

Climate change and species invasions represent key threats to global biodiversity. Subarctic freshwaters are sentinels for understanding both stressors because the effects of climate change are disproportionately strong at high latitudes and invasion of temperate species is prevalent. Here, we summarize the environmental effects of climate change and illustrate the ecological responses of freshwater fishes to these effects, spanning individual, population, community and ecosystem levels. Climate change is modifying hydrological cycles across atmospheric, terrestrial and aquatic components of subarctic ecosystems, causing increases in ambient water temperature and nutrient availability. These changes affect the individual behavior, habitat use, growth and metabolism, alter population spawning and recruitment dynamics, leading to changes in species abundance and distribution, modify food web structure, trophic interactions and energy flow within communities and change the sources, quantity and quality of energy and nutrients in ecosystems. Increases in temperature and its variability in aquatic environments underpin many ecological responses; however, altered hydrological regimes, increasing nutrient inputs and shortened ice cover are also important drivers of climate change effects and likely contribute to context-dependent responses. Species invasions are a complex aspect of the ecology of climate change because the phenomena of invasion are both an effect and a driver of the ecological consequences of climate change. Using subarctic freshwaters as an example, we illustrate how climate change can alter three distinct aspects of species invasions: (1) the vulnerability of ecosystems to be invaded, (2) the potential for species to spread and invade new habitats, and (3) the subsequent ecological effects of invaders. We identify three fundamental knowledge gaps focused on the need to determine (1) how environmental and landscape characteristics influence the ecological impact of climate change, (2) the separate and combined effects of climate and non-native invading species and (3) the underlying ecological processes or mechanisms responsible for changes in patterns of biodiversity.

How complete is our knowledge of the ecosystem services impacts of Europe's top 10 invasive species?

NASA Astrophysics Data System (ADS)

McLaughlan, C.; Gallardo, B.; Aldridge, D. C.

2014-01-01

Invasive non-native species have complex multilevel impacts on their introduced ecosystems, leading to far-ranging effects on fundamental ecosystem services, from the provision of food from that system, to human health and wellbeing. For this reason, there is an emerging interest in basing risk assessments not only on the species' ecological and economic impacts, but also on the effects related to ecosystem services. We investigated the quality and extent of baseline data detailing the effects that the top 10 of the 'worst' invasive species in Europe are having on their adopted ecosystems. The results were striking, as the 10 species showed a wide range of impacts on ecosystem services, a number of which were actually positive for ecosystems and human well-being. For instance, the bivalve Dreissena polymorpha is a prolific biofouler of pipes and boats, but it can improve water quality through its filtration of nuisance algae, a valuable effect that is often overlooked. We found that negative effects, particularly economic ones, were often assumed rather than quantitatively evidenced; for example, the cost of crop damage by species such as Myocastor coypus and Branta canadensis. In general, the evidence for impacts of these 'worst' invaders was severely lacking. We conclude that invasive species management requires prioritization, which should be based on informed and quantified assessment of the potential ecological and economic costs of species (both positive and negative), considered in the proper context of the invader and ecosystem. The Millennium Ecosystem Approach provides a useful framework to undertake such prioritization from a new perspective combining ecological and societal aspects. However, standard guidelines of evaluation are urgently needed in order to unify definitions, methods and evaluation scores.

Predicting foundation bunchgrass species abundances: Model-assisted decision-making in protected-area sagebrush steppe

USGS Publications Warehouse

Rodhouse, Thomas J.; Irvine, Kathryn M.; Sheley, Roger L.; Smith, Brenda S.; Hoh, Shirley; Esposito, Daniel M.; Mata-Gonzalez, Ricardo

2014-01-01

Foundation species are structurally dominant members of ecological communities that can stabilize ecological processes and influence resilience to disturbance and resistance to invasion. Being common, they are often overlooked for conservation but are increasingly threatened from land use change, biological invasions, and over-exploitation. The pattern of foundation species abundances over space and time may be used to guide decision-making, particularly in protected areas for which they are iconic. We used ordinal logistic regression to identify the important environmental influences on the abundance patterns of bluebunch wheatgrass (Pseudoroegneria spicata), Thurber's needlegrass (Achnatherum thurberianum), and Sandberg bluegrass (Poa secunda) in protected-area sagebrush steppe. We then predicted bunchgrass abundances along gradients of topography, disturbance, and invasive annual grass abundance. We used model predictions to prioritize the landscape for implementation of a management and restoration decision-support tool. Models were fit to categorical estimates of grass cover obtained from an extensive ground-based monitoring dataset. We found that remnant stands of abundant wheatgrass and bluegrass were associated with steep north-facing slopes in higher and more remote portions of the landscape outside of recently burned areas where invasive annual grasses were less abundant. These areas represented only 25% of the landscape and were prioritized for protection efforts. Needlegrass was associated with south-facing slopes, but in low abundance and in association with invasive cheatgrass (Bromus tectorum). Abundances of all three species were strongly negatively correlated with occurrence of another invasive annual grass, medusahead (Taeniatherum caput-medusae). The rarity of priority bunchgrass stands underscored the extent of degradation and the need for prioritization. We found no evidence that insularity reduced invasibility; annual grass invasion represents a serious threat to protected-area bunchgrass communities. Our study area was entirely within the Wyoming big sagebrush ecological zone, understood to have inherently low resilience to disturbance and resistance to weed invasion. However, our study revealed important variation in abundance of the foundation species associated with resilience and resistance along the topographic-soil moisture gradient within this zone, providing an important foothold for conservation decision-making in these steppe ecosystems. We found the foundation species focus a parsimonious strategy linking monitoring to decision-making via biogeographic modeling.

Global Invader Impact Network (GIIN): toward standardized evaluation of the ecological impacts of invasive plants.

PubMed

Barney, Jacob N; Tekiela, Daniel R; Barrios-Garcia, Maria Noelia; Dimarco, Romina D; Hufbauer, Ruth A; Leipzig-Scott, Peter; Nuñez, Martin A; Pauchard, Aníbal; Pyšek, Petr; Vítková, Michaela; Maxwell, Bruce D

2015-07-01

Terrestrial invasive plants are a global problem and are becoming ubiquitous components of most ecosystems. They are implicated in altering disturbance regimes, reducing biodiversity, and changing ecosystem function, sometimes in profound and irreversible ways. However, the ecological impacts of most invasive plants have not been studied experimentally, and most research to date focuses on few types of impacts, which can vary greatly among studies. Thus, our knowledge of existing ecological impacts ascribed to invasive plants is surprisingly limited in both breadth and depth. Our aim was to propose a standard methodology for quantifying baseline ecological impact that, in theory, is scalable to any terrestrial plant invader (e.g., annual grasses to trees) and any invaded system (e.g., grassland to forest). The Global Invader Impact Network (GIIN) is a coordinated distributed experiment composed of an observational and manipulative methodology. The protocol consists of a series of plots located in (1) an invaded area; (2) an adjacent removal treatment within the invaded area; and (3) a spatially separate uninvaded area thought to be similar to pre-invasion conditions of the invaded area. A standardized and inexpensive suite of community, soil, and ecosystem metrics are collected allowing broad comparisons among measurements, populations, and species. The method allows for one-time comparisons and for long-term monitoring enabling one to derive information about change due to invasion over time. Invader removal plots will also allow for quantification of legacy effects and their return rates, which will be monitored for several years. GIIN uses a nested hierarchical scale approach encompassing multiple sites, regions, and continents. Currently, GIIN has network members in six countries, with new members encouraged. To date, study species include representatives of annual and perennial grasses; annual and perennial forbs; shrubs; and trees. The goal of the GIIN framework is to create a standard yet flexible platform for understanding the ecological impacts of invasive plants, allowing both individual and synthetic analyses across a range of taxa and ecosystems. If broadly adopted, this standard approach will offer unique insight into the ecological impacts of invasive plants at local, regional, and global scales.

Global Invader Impact Network (GIIN): toward standardized evaluation of the ecological impacts of invasive plants

PubMed Central

Barney, Jacob N; Tekiela, Daniel R; Barrios-Garcia, Maria Noelia; Dimarco, Romina D; Hufbauer, Ruth A; Leipzig-Scott, Peter; Nuñez, Martin A; Pauchard, Aníbal; Pyšek, Petr; Vítková, Michaela; Maxwell, Bruce D

2015-01-01

Terrestrial invasive plants are a global problem and are becoming ubiquitous components of most ecosystems. They are implicated in altering disturbance regimes, reducing biodiversity, and changing ecosystem function, sometimes in profound and irreversible ways. However, the ecological impacts of most invasive plants have not been studied experimentally, and most research to date focuses on few types of impacts, which can vary greatly among studies. Thus, our knowledge of existing ecological impacts ascribed to invasive plants is surprisingly limited in both breadth and depth. Our aim was to propose a standard methodology for quantifying baseline ecological impact that, in theory, is scalable to any terrestrial plant invader (e.g., annual grasses to trees) and any invaded system (e.g., grassland to forest). The Global Invader Impact Network (GIIN) is a coordinated distributed experiment composed of an observational and manipulative methodology. The protocol consists of a series of plots located in (1) an invaded area; (2) an adjacent removal treatment within the invaded area; and (3) a spatially separate uninvaded area thought to be similar to pre-invasion conditions of the invaded area. A standardized and inexpensive suite of community, soil, and ecosystem metrics are collected allowing broad comparisons among measurements, populations, and species. The method allows for one-time comparisons and for long-term monitoring enabling one to derive information about change due to invasion over time. Invader removal plots will also allow for quantification of legacy effects and their return rates, which will be monitored for several years. GIIN uses a nested hierarchical scale approach encompassing multiple sites, regions, and continents. Currently, GIIN has network members in six countries, with new members encouraged. To date, study species include representatives of annual and perennial grasses; annual and perennial forbs; shrubs; and trees. The goal of the GIIN framework is to create a standard yet flexible platform for understanding the ecological impacts of invasive plants, allowing both individual and synthetic analyses across a range of taxa and ecosystems. If broadly adopted, this standard approach will offer unique insight into the ecological impacts of invasive plants at local, regional, and global scales. PMID:26306173

Unifying ecology and macroevolution with individual-based theory

PubMed Central

Rosindell, James; Harmon, Luke J; Etienne, Rampal S

2015-01-01

A contemporary goal in both ecology and evolutionary biology is to develop theory that transcends the boundary between the two disciplines, to understand phenomena that cannot be explained by either field in isolation. This is challenging because macroevolution typically uses lineage-based models, whereas ecology often focuses on individual organisms. Here, we develop a new parsimonious individual-based theory by adding mild selection to the neutral theory of biodiversity. We show that this model generates realistic phylogenies showing a slowdown in diversification and also improves on the ecological predictions of neutral theory by explaining the occurrence of very common species. Moreover, we find the distribution of individual fitness changes over time, with average fitness increasing at a pace that depends positively on community size. Consequently, large communities tend to produce fitter species than smaller communities. These findings have broad implications beyond biodiversity theory, potentially impacting, for example, invasion biology and paleontology. PMID:25818618

Unifying ecology and macroevolution with individual-based theory.

PubMed

Rosindell, James; Harmon, Luke J; Etienne, Rampal S

2015-05-01

A contemporary goal in both ecology and evolutionary biology is to develop theory that transcends the boundary between the two disciplines, to understand phenomena that cannot be explained by either field in isolation. This is challenging because macroevolution typically uses lineage-based models, whereas ecology often focuses on individual organisms. Here, we develop a new parsimonious individual-based theory by adding mild selection to the neutral theory of biodiversity. We show that this model generates realistic phylogenies showing a slowdown in diversification and also improves on the ecological predictions of neutral theory by explaining the occurrence of very common species. Moreover, we find the distribution of individual fitness changes over time, with average fitness increasing at a pace that depends positively on community size. Consequently, large communities tend to produce fitter species than smaller communities. These findings have broad implications beyond biodiversity theory, potentially impacting, for example, invasion biology and paleontology. © 2015 The Authors. Ecology Letters published by John Wiley & Sons Ltd and CNRS.

Mechanical Harvesting Effectively Controls Young Typha spp. Invasion and Unmanned Aerial Vehicle Data Enhances Post-treatment Monitoring

PubMed Central

Lishawa, Shane C.; Carson, Brendan D.; Brandt, Jodi S.; Tallant, Jason M.; Reo, Nicholas J.; Albert, Dennis A.; Monks, Andrew M.; Lautenbach, Joseph M.; Clark, Eric

2017-01-01

The ecological impacts of invasive plants increase dramatically with time since invasion. Targeting young populations for treatment is therefore an economically and ecologically effective management approach, especially when linked to post-treatment monitoring to evaluate the efficacy of management. However, collecting detailed field-based post-treatment data is prohibitively expensive, typically resulting in inadequate documentation of the ecological effects of invasive plant management. Alternative approaches, such as remote detection with unmanned aerial vehicles (UAV), provide an opportunity to advance the science and practice of restoration ecology. In this study, we sought to determine the plant community response to different mechanical removal treatments to a dominant invasive wetland macrophyte (Typha spp.) along an age-gradient within a Great Lakes coastal wetland. We assessed the post-treatment responses with both intensive field vegetation and UAV data. Prior to treatment, the oldest Typha stands had the lowest plant diversity, lowest native sedge (Carex spp.) cover, and the greatest Typha cover. Following treatment, plots that were mechanically harvested below the surface of the water differed from unharvested control and above-water harvested plots for several plant community measures, including lower Typha dominance, lower native plant cover, and greater floating and submerged aquatic species cover. Repeated-measures analysis revealed that above-water cutting increased plant diversity and aquatic species cover across all ages, and maintained native Carex spp. cover in the youngest portions of Typha stands. UAV data revealed significant post-treatment differences in normalized difference vegetation index (NDVI) scores, blue band reflectance, and vegetation height, and these remotely collected measures corresponded to field observations. Our findings suggest that both mechanically harvesting the above-water biomass of young Typha stands and harvesting older stands below-water will promote overall native community resilience, and increase the abundance of the floating and submerged aquatic plant guilds, which are the most vulnerable to invasions by large macrophytes. UAV's provided fast and spatially expansive data compared to field monitoring, and effectively measured plant community structural responses to different treatments. Study results suggest pairing UAV flights with targeted field data collection to maximize the quality of post-restoration vegetation monitoring. PMID:28487713

Earthworms as Invasive Species in Latin America — the 2nd Latin American Meeting on Oligochaeta (Earthworm) Ecology and Taxonomy

Treesearch

Grizelle Gonzalez

2006-01-01

This special issue is based on scientific contributions presented at the 2nd Latin American Symposium of Earthworm Ecology and Taxonomy (ELAETAO, for its Spanish acronym) held in San Juan, Puerto Rico November 14-18, 2005. The first of these symposia was organized by George G. Brown and Klaus D. Sautter and held at Londrina, Brazil from December 1-3, 2003.The objective...

Predicting the potential distribution of invasive exotic species using GIS and information-theoretic approaches: A case of ragweed (Ambrosia artemisiifolia L.) distribution in China

USGS Publications Warehouse

Hao, Chen; LiJun, Chen; Albright, Thomas P.

2007-01-01

Invasive exotic species pose a growing threat to the economy, public health, and ecological integrity of nations worldwide. Explaining and predicting the spatial distribution of invasive exotic species is of great importance to prevention and early warning efforts. We are investigating the potential distribution of invasive exotic species, the environmental factors that influence these distributions, and the ability to predict them using statistical and information-theoretic approaches. For some species, detailed presence/absence occurrence data are available, allowing the use of a variety of standard statistical techniques. However, for most species, absence data are not available. Presented with the challenge of developing a model based on presence-only information, we developed an improved logistic regression approach using Information Theory and Frequency Statistics to produce a relative suitability map. This paper generated a variety of distributions of ragweed (Ambrosia artemisiifolia L.) from logistic regression models applied to herbarium specimen location data and a suite of GIS layers including climatic, topographic, and land cover information. Our logistic regression model was based on Akaike's Information Criterion (AIC) from a suite of ecologically reasonable predictor variables. Based on the results we provided a new Frequency Statistical method to compartmentalize habitat-suitability in the native range. Finally, we used the model and the compartmentalized criterion developed in native ranges to "project" a potential distribution onto the exotic ranges to build habitat-suitability maps. ?? Science in China Press 2007.

Biological control is more than just natural enemies

Treesearch

Dean E. Pearson

2005-01-01

The past decade has given rise to exciting new developments in the field of community ecology that have profound implications for biological control. The recognition that biological invasions offer unprecedented opportunities to investigate the nature of community assembly has swept invasive species studies to the forefront of popular ecology. Meanwhile,...

Ecological Consequences of Clonal Integration in Plants

PubMed Central

Liu, Fenghong; Liu, Jian; Dong, Ming

2016-01-01

Clonal plants are widespread throughout the plant kingdom and dominate in diverse habitats. Spatiotemporal heterogeneity of environment is pervasive at multiple scales, even at scales relevant to individual plants. Clonal integration refers to resource translocation and information communication among the ramets of clonal plants. Due to clonal integration, clonal plant species possess a series of peculiar attributes: plasticity in response to local and non-local conditions, labor division with organ specialization for acquiring locally abundant resources, foraging behavior by selective placement of ramets in resource-rich microhabitats, and avoidance of intraclonal competition. Clonal integration has very profound ecological consequences for clonal plants. It allows them to efficiently cope with environmental heterogeneity, by alleviating local resource shortages, buffering environmental stresses and disturbances, influencing competitive ability, increasing invasiveness, and altering species composition and invasibility at the community level. In this paper, we present a comprehensive review of research on the ecological consequences of plant clonal integration based on a large body of literature. We also attempt to propose perspectives for future research. PMID:27446093

A framework for spatial risk assessments: Potential impacts of nonindigenous invasive species on native species

USGS Publications Warehouse

Allen, Craig R.; Johnson, A.R.; Parris, L.

2006-01-01

Many populations of wild animals and plants are declining and face increasing threats from habitat fragmentation and loss as well as exposure to stressors ranging from toxicants to diseases to invasive nonindigenous species. We describe and demonstrate a spatially explicit ecological risk assessment that allows for the incorporation of a broad array of information that may influence the distribution of an invasive species, toxicants, or other stressors, and the incorporation of landscape variables that may influence the spread of a species or substances. The first step in our analyses is to develop species models and quantify spatial overlap between stressor and target organisms. Risk is assessed as the product of spatial overlap and a hazard index based on target species vulnerabilities to the stressor of interest. We illustrate our methods with an example in which the stressor is the ecologically destructive nonindigenous ant, Solenopsis invicta, and the targets are two declining vertebrate species in the state of South Carolina, USA. A risk approach that focuses on landscapes and that is explicitly spatial is of particular relevance as remaining undeveloped lands become increasingly uncommon and isolated and more important in the management and recovery of species and ecological systems. Effective ecosystem management includes the control of multiple stressors, including invasive species with large impacts, understanding where those impacts may be the most severe, and implementing management strategies to reduce impacts. Copyright ?? 2006 by the author(s).

Research on the fundamental principles of China's marine invasive species prevention legislation.

PubMed

Bai, Jiayu

2014-12-15

China's coastal area is severely damaged by marine invasive species. Traditional tort theory resolves issues relevant to property damage or personal injuries, through which plaintiffs cannot cope with the ecological damage caused by marine invasive species. Several defects exist within the current legal regimes, such as imperfect management systems, insufficient unified technical standards, and unsound legal responsibility systems. It is necessary to pass legislation to prevent the ecological damage caused by marine invasive species. This investigation probes the fundamental principles needed for the administration and legislation of an improved legal framework to combat the problem of invasive species within China's coastal waters. Copyright © 2014 Elsevier Ltd. All rights reserved.

No evidence for ecological segregation protecting native trout from invasive hybridization

USGS Publications Warehouse

Kovach, Ryan; Muhlfeld, Clint C.; Al-Chokhachy, Robert K.; Amish, Stephen J.; Kershner, Jeffrey L.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Matson, Phil; Schmetterling, David; Shepard, Bradley; Westley, Peter A. H.; Whited, Diane; Whiteley, Andrew R.; Allendorf, Fred W.

2017-01-01

We appreciate the comments of Young et al. (2017) on our recent paper (Muhlfeld et al., 2017) concerning spatiotemporal dynamics of hybridization between native westslope cutthroat trout (Oncorhynchus clarkii lewisi; WCT) and introduced coastal rainbow trout (Oncorhynchus mykiss irideus; RBT). Nevertheless, we believe there is no evidence for “ecological segregation” protecting WCT from hybridization with invasive RBT. Here we consider their three major arguments for ecological segregation and find their conclusions invalid.

Local-scale invasion pathways and small founder numbers in introduced Sacramento pikeminnow (Ptychocheilus grandis)

Treesearch

Andrew P. Kinziger; Rodney J. Nakamoto; Bret C. Harvey

2014-01-01

Given the general pattern of invasions with severe ecological consequences commonly resulting from multiple introductions of large numbers of individuals on the intercontinental scale, we explored an example of a highly successful, ecologically significant invader introduced over a short distance, possibly via minimal propagule pressure. The Sacramento pikeminnow (

Clarifying values, risk perceptions, and attitudes to resolve or avoid social conflicts in invasive species management.

PubMed

Estévez, Rodrigo A; Anderson, Christopher B; Pizarro, J Cristobal; Burgman, Mark A

2015-02-01

Decision makers and researchers recognize the need to effectively confront the social dimensions and conflicts inherent to invasive species research and management. Yet, despite numerous contentious situations that have arisen, no systematic evaluation of the literature has examined the commonalities in the patterns and types of these emergent social issues. Using social and ecological keywords, we reviewed trends in the social dimensions of invasive species research and management and the sources and potential solutions to problems and conflicts that arise around invasive species. We integrated components of cognitive hierarchy theory and risk perceptions theory to provide a conceptual framework to identify, distinguish, and provide understanding of the driving factors underlying disputes associated with invasive species. In the ISI Web of Science database, we found 15,915 peer-reviewed publications on biological invasions, 124 of which included social dimensions of this phenomenon. Of these 124, 28 studies described specific contentious situations. Social approaches to biological invasions have emerged largely in the last decade and have focused on both environmental social sciences and resource management. Despite being distributed in a range of journals, these 124 articles were concentrated mostly in ecology and conservation-oriented outlets. We found that conflicts surrounding invasive species arose based largely on differences in value systems and to a lesser extent stakeholder and decision maker's risk perceptions. To confront or avoid such situations, we suggest integrating the plurality of environmental values into invasive species research and management via structured decision making techniques, which enhance effective risk communication that promotes trust and confidence between stakeholders and decision makers. © 2014 Society for Conservation Biology.

An invasive plant alters phenotypic selection on the vegetative growth of a native congener.

PubMed

Beans, Carolyn M; Roach, Deborah A

2015-02-01

The ecological consequences of plant competition have frequently been tested, but the evolutionary outcomes of these interactions have gone largely unexplored. The study of species invasions can make an important contribution to this field of research by allowing us to watch ecological and evolutionary processes unfold as a novel species is integrated into a plant community. We explored the ecological and evolutionary impact of an invasive jewelweed, Impatiens glandulifera, on a closely related native congener, I. capensis and asked: (1) Does the presence of the invasive jewelweed alter the fitness of native jewelweed populations? (2) Does the invasive jewelweed affect the vegetative growth of the native congener? and (3) Does the invasive jewelweed alter phenotypic selection on the vegetative traits of the native congener? We used a greenhouse competition experiment, an invasive species removal field experiment, and a survey of natural populations. We show that when the invasive jewelweed is present, phenotypic selection favors native jewelweed individuals investing less in rapid upward growth and more in branching and fruiting potential through the production of nodes. This research demonstrates that invasive plants have the potential to greatly alter natural selection on native competitors. Studies investigating altered selection in invaded communities can reveal the potential evolutionary impact of invasive competitors, while deepening our understanding of the more general role of competition in driving plant evolution and permitting species coexistence. © 2015 Botanical Society of America, Inc.

Predicting trends of invasive plants richness using local socio-economic data: An application in North Portugal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos, Mario, E-mail: mgsantoss@gmail.com; Freitas, Raul, E-mail: raulfreitas@portugalmail.com; Crespi, Antonio L., E-mail: aluis.crespi@gmail.com

2011-10-15

This study assesses the potential of an integrated methodology for predicting local trends in invasive exotic plant species (invasive richness) using indirect, regional information on human disturbance. The distribution of invasive plants was assessed in North Portugal using herbarium collections and local environmental, geophysical and socio-economic characteristics. Invasive richness response to anthropogenic disturbance was predicted using a dynamic model based on a sequential modeling process (stochastic dynamic methodology-StDM). Derived scenarios showed that invasive richness trends were clearly associated with ongoing socio-economic change. Simulations including scenarios of growing urbanization showed an increase in invasive richness while simulations in municipalities with decreasingmore » populations showed stable or decreasing levels of invasive richness. The model simulations demonstrate the interest and feasibility of using this methodology in disturbance ecology. - Highlights: {yields} Socio-economic data indicate human induced disturbances. {yields} Socio-economic development increase disturbance in ecosystems. {yields} Disturbance promotes opportunities for invasive plants.{yields} Increased opportunities promote richness of invasive plants.{yields} Increase in richness of invasive plants change natural ecosystems.« less

77 FR 23740 - Invasive Species Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-20

... Commerce. The duty of the Council is to provide national leadership regarding invasive species issues... both ecological and management contexts, will center on topics that: (1) Pertain to invasive species...

Generating an agricultural risk map based on limited ecological information: A case study using Sicyos angulatus.

PubMed

Osawa, Takeshi; Okawa, Shigenori; Kurokawa, Shunji; Ando, Shinichiro

2016-12-01

In this study, we propose a method for estimating the risk of agricultural damage caused by an invasive species when species-specific information is lacking. We defined the "risk" as the product of the invasion probability and the area of potentially damaged crop for production. As a case study, we estimated the risk imposed by an invasive weed, Sicyos angulatus, based on simple cellular simulations and governmental data on the area of crop that could potentially be damaged in Miyagi Prefecture, Japan. Simulation results revealed that the current distribution range was sufficiently accurate for practical purposes. Using these results and records of crop areas, we present risk maps for S. angulatus in agricultural fields. Managers will be able to use these maps to rapidly establish a management plan with minimal cost. Our approach will be valuable for establishing a management plan before or during the early stages of invasion.

Revisiting the ants of Melanesia and the taxon cycle: historical and human-mediated invasions of a tropical archipelago.

PubMed

Economo, Evan P; Sarnat, Eli M

2012-07-01

Understanding the historical evolution of biotas and the dynamics of contemporary human-mediated species introductions are two central tasks of biology. One hypothesis may address both-the taxon cycle. Taxon cycles are phases of range expansion and contraction coupled to ecological and evolutionary niche shifts. These historical invasion processes resemble human-mediated invasions in pattern and possibly mechanism, but both the existence of historical cycles and the roles of recent introductions are in question. We return to the system that originally inspired the taxon cycle-Melanesian ants-and perform novel tests of the hypothesis. We analyze (i) the habitat distributions of Fiji's entire ant fauna (183 species), (ii) ecological shifts associated with the in situ radiation of Fijian Pheidole in a phylogenetic context, and (iii) the ecological structure of a massive exotic ant invasion of the archipelago. Our analyses indicate lineages shift toward primary habitats, higher elevation, rarity, and ecological specialization with increasing level of endemism, consistent with taxon cycle predictions. The marginal habitats that historically formed a dispersal conduit in the Pacific are now mostly replaced by human-modified habitats dominated by a colonization pulse of exotic species. We propose this may represent the first phase of an incipient global cycle of human-mediated colonization, ecological shifts, and diversification.

Coupling ecological and social network models to assess "transmission" and "contagion" of an aquatic invasive species.

PubMed

Haak, Danielle M; Fath, Brian D; Forbes, Valery E; Martin, Dustin R; Pope, Kevin L

2017-04-01

Network analysis is used to address diverse ecological, social, economic, and epidemiological questions, but few efforts have been made to combine these field-specific analyses into interdisciplinary approaches that effectively address how complex systems are interdependent and connected to one another. Identifying and understanding these cross-boundary connections improves natural resource management and promotes proactive, rather than reactive, decisions. This research had two main objectives; first, adapt the framework and approach of infectious disease network modeling so that it may be applied to the socio-ecological problem of spreading aquatic invasive species, and second, use this new coupled model to simulate the spread of the invasive Chinese mystery snail (Bellamya chinensis) in a reservoir network in Southeastern Nebraska, USA. The coupled model integrates an existing social network model of how anglers move on the landscape with new reservoir-specific ecological network models. This approach allowed us to identify 1) how angler movement among reservoirs aids in the spread of B. chinensis, 2) how B. chinensis alters energy flows within individual-reservoir food webs, and 3) a new method for assessing the spread of any number of non-native or invasive species within complex, social-ecological systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coupling ecological and social network models to assess “transmission” and “contagion” of an aquatic invasive species

USGS Publications Warehouse

Haak, Danielle M.; Fath, Brian D.; Forbes, Valery E.; Martin, Dustin R.; Pope, Kevin L.

2017-01-01

Network analysis is used to address diverse ecological, social, economic, and epidemiological questions, but few efforts have been made to combine these field-specific analyses into interdisciplinary approaches that effectively address how complex systems are interdependent and connected to one another. Identifying and understanding these cross-boundary connections improves natural resource management and promotes proactive, rather than reactive, decisions. This research had two main objectives; first, adapt the framework and approach of infectious disease network modeling so that it may be applied to the socio-ecological problem of spreading aquatic invasive species, and second, use this new coupled model to simulate the spread of the invasive Chinese mystery snail (Bellamya chinensis) in a reservoir network in Southeastern Nebraska, USA. The coupled model integrates an existing social network model of how anglers move on the landscape with new reservoir-specific ecological network models. This approach allowed us to identify 1) how angler movement among reservoirs aids in the spread of B. chinensis, 2) how B. chinensisalters energy flows within individual-reservoir food webs, and 3) a new method for assessing the spread of any number of non-native or invasive species within complex, social-ecological systems.

Random forests for classification in ecology

USGS Publications Warehouse

Cutler, D.R.; Edwards, T.C.; Beard, K.H.; Cutler, A.; Hess, K.T.; Gibson, J.; Lawler, J.J.

2007-01-01

Classification procedures are some of the most widely used statistical methods in ecology. Random forests (RF) is a new and powerful statistical classifier that is well established in other disciplines but is relatively unknown in ecology. Advantages of RF compared to other statistical classifiers include (1) very high classification accuracy; (2) a novel method of determining variable importance; (3) ability to model complex interactions among predictor variables; (4) flexibility to perform several types of statistical data analysis, including regression, classification, survival analysis, and unsupervised learning; and (5) an algorithm for imputing missing values. We compared the accuracies of RF and four other commonly used statistical classifiers using data on invasive plant species presence in Lava Beds National Monument, California, USA, rare lichen species presence in the Pacific Northwest, USA, and nest sites for cavity nesting birds in the Uinta Mountains, Utah, USA. We observed high classification accuracy in all applications as measured by cross-validation and, in the case of the lichen data, by independent test data, when comparing RF to other common classification methods. We also observed that the variables that RF identified as most important for classifying invasive plant species coincided with expectations based on the literature. ?? 2007 by the Ecological Society of America.

Social-ecological predictors of global invasions and extinctions

USGS Publications Warehouse

Lotz, Aaron; Allen, Craig R.

2013-01-01

Most assessments of resilience have been focused on local conditions. Studies focused on the relationship between humanity and environmental degradation are rare, and are rarely comprehensive. We investigated multiple social-ecological factors for 100 countries around the globe in relation to the percentage of invasions and extinctions within each country. These 100 countries contain approximately 87% of the world’s population, produce 43% of the world’s per capita gross domestic product (GDP), and take up 74% of the earth’s total land area. We used an information theoretic approach to determine which models were most supported by our data, utilizing an a priori set of plausible models that included a combination of 15 social-ecological variables, each social-ecological factor by itself, and selected social-ecological factors grouped into three broad classes. These variables were per capita GDP, export-import ratio, tourism, undernourishment, energy efficiency, agricultural intensity, rainfall, water stress, wilderness protection, total biodiversity, life expectancy, adult literacy, pesticide regulation, political stability, and female participation in government. Our results indicate that as total biodiversity and total land area increase, the percentage of endangered birds also increases. As the independent variables (agricultural intensity, rainfall, water stress, and total biodiversity) in the ecological class model increase, the percentage of endangered mammals in a country increases. The percentage of invasive birds and mammals in a country increases as per capita GDP increases. As life expectancy increases, the percentage of invasive and endangered birds and mammals increases. Although our analysis does not determine mechanisms, the patterns observed in this study provide insight into the dynamics of a complex, global, social-ecological system.

Snakes on the Balearic islands: an invasion tale with implications for native biodiversity conservation.

PubMed

Silva-Rocha, Iolanda; Salvi, Daniele; Sillero, Neftalí; Mateo, Jose A; Carretero, Miguel A

2015-01-01

Biological invasions are a major conservation threat for biodiversity worldwide. Islands are particularly vulnerable to invasive species, especially Mediterranean islands which have suffered human pressure since ancient times. In the Balearic archipelago, reptiles represent an outstanding case with more alien than native species. Moreover, in the last decade a new wave of alien snakes landed in the main islands of the archipelago, some of which were originally snake-free. The identification of the origin and colonization pathways of alien species, as well as the prediction of their expansion, is crucial to develop effective conservation strategies. In this study, we used molecular markers to assess the allochthonous status and the putative origin of the four introduced snake species (Hemorrhois hippocrepis, Malpolon monspessulanus, Macroprotodon mauritanicus and Rhinechis scalaris) as well as ecological niche models to infer their patterns of invasion and expansion based on current and future habitat suitability. For most species, DNA sequence data suggested the Iberian Peninsula as the potential origin of the allochthonous populations, although the shallow phylogeographic structure of these species prevented the identification of a restricted source-area. For all of them, the ecological niche models showed a current low habitat suitability in the Balearic, which is however predicted to increase significantly in the next few decades under climate change scenarios. Evidence from direct observations and spatial distribution of the first-occurrence records of alien snakes (but also lizards and worm lizards) suggest the nursery trade, and in particular olive tree importation from Iberian Peninsula, as the main pathway of introduction of alien reptiles in the Balearic islands. This trend has been reported also for recent invasions in NE Spain, thus showing that olive trees transplantation may be an effective vector for bioinvasion across the Mediterranean. The combination of molecular and ecological tools used in this study reveals a promising approach for the understanding of the complex invasion process, hence guiding conservation management actions.

Snakes on the Balearic Islands: An Invasion Tale with Implications for Native Biodiversity Conservation

PubMed Central

Sillero, Neftalí; Mateo, Jose A.; Carretero, Miguel A.

2015-01-01

Biological invasions are a major conservation threat for biodiversity worldwide. Islands are particularly vulnerable to invasive species, especially Mediterranean islands which have suffered human pressure since ancient times. In the Balearic archipelago, reptiles represent an outstanding case with more alien than native species. Moreover, in the last decade a new wave of alien snakes landed in the main islands of the archipelago, some of which were originally snake-free. The identification of the origin and colonization pathways of alien species, as well as the prediction of their expansion, is crucial to develop effective conservation strategies. In this study, we used molecular markers to assess the allochthonous status and the putative origin of the four introduced snake species (Hemorrhois hippocrepis, Malpolon monspessulanus, Macroprotodon mauritanicus and Rhinechis scalaris) as well as ecological niche models to infer their patterns of invasion and expansion based on current and future habitat suitability. For most species, DNA sequence data suggested the Iberian Peninsula as the potential origin of the allochthonous populations, although the shallow phylogeographic structure of these species prevented the identification of a restricted source-area. For all of them, the ecological niche models showed a current low habitat suitability in the Balearic, which is however predicted to increase significantly in the next few decades under climate change scenarios. Evidence from direct observations and spatial distribution of the first-occurrence records of alien snakes (but also lizards and worm lizards) suggest the nursery trade, and in particular olive tree importation from Iberian Peninsula, as the main pathway of introduction of alien reptiles in the Balearic islands. This trend has been reported also for recent invasions in NE Spain, thus showing that olive trees transplantation may be an effective vector for bioinvasion across the Mediterranean. The combination of molecular and ecological tools used in this study reveals a promising approach for the understanding of the complex invasion process, hence guiding conservation management actions. PMID:25853711

Invasive species in agriculture

USDA-ARS?s Scientific Manuscript database

Agricultural production of food, feed, fiber or fuel is a local human activity with global ecological impacts, including the potential to foster invasions. Agriculture plays an unusual role in biological invasions, in that it is both a source of non-indigenous invasive species (NIS) and especially s...

The role of hybridization in facilitating tree invasion

USDA-ARS?s Scientific Manuscript database

Hybridization events can generate additional genetic diversity on which natural selection can act and at times enhance invasiveness of the species. Invasive tree species are a growing ecological concern worldwide, and some of these invasions involve hybridization events pre- or post-introduction. Th...

Biogeographical plant-soil relations of invasive medusahead (Elymus caput-medusae)

USDA-ARS?s Scientific Manuscript database

Understanding the mechanisms that underlie the success of invasive plant species is integral to predicting and ameliorating their negative impacts. Many hypotheses have consequently been proposed to explain invasive behavior. This lack of consensus within invasion ecology can partially be attributed...

Examining Ecological and Ecosystem Level Impacts of Aquatic Invasive Species in Lake Michigan Using An Ecosystem Productivity Model, LM-Eco

EPA Science Inventory

Ecological and ecosystem-level impacts of aquatic invasive species in Lake Michigan were examined using the Lake Michigan Ecosystem Model (LM-Eco). The LM-Eco model includes a detailed description of trophic levels and their interactions within the lower food web of Lake Michiga...

Parasites and genetic diversity in an invasive bumblebee.

PubMed

Jones, Catherine M; Brown, Mark J F

2014-11-01

Biological invasions are facilitated by the global transportation of species and climate change. Given that invasions may cause ecological and economic damage and pose a major threat to biodiversity, understanding the mechanisms behind invasion success is essential. Both the release of non-native populations from natural enemies, such as parasites, and the genetic diversity of these populations may play key roles in their invasion success. We investigated the roles of parasite communities, through enemy release and parasite acquisition, and genetic diversity in the invasion success of the non-native bumblebee, Bombus hypnorum, in the United Kingdom. The invasive B. hypnorum had higher parasite prevalence than most, or all native congeners for two high-impact parasites, probably due to higher susceptibility and parasite acquisition. Consequently parasites had a higher impact on B. hypnorum queens' survival and colony-founding success than on native species. Bombus hypnorum also had lower functional genetic diversity at the sex-determining locus than native species. Higher parasite prevalence and lower genetic diversity have not prevented the rapid invasion of the United Kingdom by B. hypnorum. These data may inform our understanding of similar invasions by commercial bumblebees around the world. This study suggests that concerns about parasite impacts on the small founding populations common to re-introduction and translocation programs may be less important than currently believed. © 2014 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Temporal and nonlinear dispersal patterns of Ludwigia hexapetala in a regulated river

USDA-ARS?s Scientific Manuscript database

Rivers are vulnerable to biological invasion due to hydrologic connectivity, which facilitates post-entry movement of aquatic plant propagules by water currents. Ecological and watershed factors may influence spatial and temporal dispersal patterns. Field-based data on dispersal could improve risk...

Links between Plant Invasion, Anthropogenic Nitrogen Enrichment, and Wildfires: A Systematic Review

NASA Astrophysics Data System (ADS)

Felker-Quinn, E.; Gooding Lassiter, M.; Maxwell, A.; Housego, R.; Young, B.

2014-12-01

Wildfires can become positive feedbacks in climate change scenarios, because wildfires release large amounts of carbon sequestered in plants and soil to the atmosphere, and because their frequency increases with increasing temperatures. Invasive plants represent an important biotic link between anthropogenic activity and wildfire, as many of these species benefit from human disturbance while increasing fire frequency and severity. A robust body of literature addresses the response of invasive species to nitrogen enrichment, and a separate body of research assesses the feedbacks between invasive plant species and wildfire. We have undertaken a systematic review of these fields in order to evaluate the hypothesis that anthropogenic nitrogen loading contributes to increasing wildfires by promoting the growth and spread of fire-adapted invasive plant species. We identified invasive plant species using the Fire Effects Information System (FEIS), a Forest Service database that evaluates fire ecology of species identified as being of concern by land managers. We used information contained in the FEIS as well as more recent studies to characterize species on a continuum from fire-adapted to fire-intolerant based on traits related to interactions of fire with survival, reproduction, and spread. Of the 107 invasive plant species with fire ecology reports in the FEIS, we have initially classified 18 as fire-adapted, possessing traits that intensify fire regimes. Additionally, 33 species are fire-tolerant, benefiting from fire primarily because it creates a high-resource, low-competition environment. In continuing work, we are evaluating the responses of the invasive plant species to increased anthropogenic nitrogen with a focus on traits such as germination, productivity, and survival, as these traits contribute to wildfire frequency and severity. The views expressed in this abstract are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

Dietary flexibility aids Asian earthworm invasion in North American forests.

PubMed

Zhang, Weixin; Hendrix, Paul F; Snyder, Bruce A; Molina, Marirosa; Li, Jianxiong; Rao, Xingquan; Siemann, Evan; Fu, Shenglei

2010-07-01

On a local scale, invasiveness of introduced species and invasibility of habitats together determine invasion success. A key issue in invasion ecology has been how to quantify the contribution of species invasiveness and habitat invasibility separately. Conventional approaches, such as comparing the differences in traits and/or impacts of species between native and/or invaded ranges, do not determine the extent to which the performance of invaders is due to either the effects of species traits or habitat characteristics. Here we explore the interaction between two of the most widespread earthworm invaders in the world (Asian Amynthas agrestis and European Lumbricus rubellus) and study the effects of species invasiveness and habitat invasibility separately through an alternative approach of "third habitat" in Tennessee, USA. We propose that feeding behaviors of earthworms will be critical to invasion success because trophic ecology of invasive animals plays a key role in the invasion process. We found that (1) the biomass and isotopic abundances (delta13C and delta15N) of A. agrestis were not impacted by either direct effects of L. rubellus competition or indirect effects of L. rubellus-preconditioned habitat; (2) A. agrestis disrupted the relationship between L. rubellus and soil microorganisms and consequently hindered litter consumption by L. rubellus; and (3) compared to L. rubellus, A. agrestis shifted its diet more readily to consume more litter, more soil gram-positive (G+) bacteria (which may be important for litter digestion), and more non-microbial soil fauna when soil microorganisms were depleted. In conclusion, A. agrestis showed strong invasiveness through its dietary flexibility through diet shifting and superior feeding behavior and its indirectly negative effect of habitat invasibility on L. rubellus via changes in the soil microorganism community. In such context, our results expand on the resource fluctuation hypothesis and support the superior competitor hypothesis. This work presents additional approaches in invasion ecology, provides some new dimensions for further research, and contributes to a greater understanding of the importance of interactions between multiple invading species.

NASA and USGS invest in invasive species modeling to evaluate habitat for Africanized Honey Bees

USGS Publications Warehouse

2009-01-01

Invasive non-native species, such as plants, animals, and pathogens, have long been an interest to the U.S. Geological Survey (USGS) and NASA. Invasive species cause harm to our economy (around $120 B/year), the environment (e.g., replacing native biodiversity, forest pathogens negatively affecting carbon storage), and human health (e.g., plague, West Nile virus). Five years ago, the USGS and NASA formed a partnership to improve ecological forecasting capabilities for the early detection and containment of the highest priority invasive species. Scientists from NASA Goddard Space Flight Center (GSFC) and the Fort Collins Science Center developed a longterm strategy to integrate remote sensing capabilities, high-performance computing capabilities and new spatial modeling techniques to advance the science of ecological invasions [Schnase et al., 2002].

Process-based management approaches for salt desert shrublands dominated by downy brome

USDA-ARS?s Scientific Manuscript database

Downy brome grass (Bromus tectorum L.) invasion has severely altered key ecological processes such as disturbance regimes, soil nutrient cycling, community assembly, and successional pathways in semi-arid Great Basin salt desert shrublands. Restoring the structure and function of these severly alte...

Genome-wide single nucleotide polymorphisms (SNPs) for a model invasive ascidian Botryllus schlosseri.

PubMed

Gao, Yangchun; Li, Shiguo; Zhan, Aibin

2018-04-01

Invasive species cause huge damages to ecology, environment and economy globally. The comprehensive understanding of invasion mechanisms, particularly genetic bases of micro-evolutionary processes responsible for invasion success, is essential for reducing potential damages caused by invasive species. The golden star tunicate, Botryllus schlosseri, has become a model species in invasion biology, mainly owing to its high invasiveness nature and small well-sequenced genome. However, the genome-wide genetic markers have not been well developed in this highly invasive species, thus limiting the comprehensive understanding of genetic mechanisms of invasion success. Using restriction site-associated DNA (RAD) tag sequencing, here we developed a high-quality resource of 14,119 out of 158,821 SNPs for B. schlosseri. These SNPs were relatively evenly distributed at each chromosome. SNP annotations showed that the majority of SNPs (63.20%) were located at intergenic regions, and 21.51% and 14.58% were located at introns and exons, respectively. In addition, the potential use of the developed SNPs for population genomics studies was primarily assessed, such as the estimate of observed heterozygosity (H O ), expected heterozygosity (H E ), nucleotide diversity (π), Wright's inbreeding coefficient (F IS ) and effective population size (Ne). Our developed SNP resource would provide future studies the genome-wide genetic markers for genetic and genomic investigations, such as genetic bases of micro-evolutionary processes responsible for invasion success.

Long-term record of Argentine ant invasions reveals enduring ecological impacts.

PubMed

Menke, Sean B; Ward, Philip S; Holway, David A

2018-05-01

The ecological effects of species introductions can change in magnitude over time, but an understanding of how and why they do so remains incompletely understood. Clarifying this issue requires consideration of how temporal variation in invader traits affects invasion impacts (e.g., through differential effects on the diversity and composition of native species assemblages). We examine the temporal dynamics of Argentine ant invasions in northern California by resurveying 202 sites first sampled 30-40 yr ago. To test how invasion impacts change over time, we estimated native ant richness and species composition at 20 riparian woodland sites that span a 30-yr invasion chronosequence. We then use these data to test how variation in two invader traits (aggression and relative abundance) is related to time since invasion and invasion impact. Native ant assemblages along the chronosequence exhibited reduced native ant richness and altered species composition (compared to uninvaded control sites), but the magnitude of these impacts was independent of time since invasion. These results are corroborated by additional temporal comparisons of native ant assemblages at riparian sites sampled 20-30 yr ago. Our findings together illustrate that the impacts of invasions can persist undiminished over at least a 30-yr time frame and remain evident at regional scales. Although neither invader trait varied with time since invasion, native ant richness declined as the relative abundance of the Argentine ant increased. This latter result supports the hypothesis that factors reducing invader abundance at particular sites can decrease invasion impacts, but also that such changes may be due to site-specific factors (e.g., abiotic conditions) that affect invader abundance rather than time since invasion per se. Future studies should attempt to differentiate factors that are intrinsic to the process of invasion (e.g., changes in invader populations) from long-term environmental changes (e.g., climate change) that represent extrinsic influences on the dynamics of invasion. © 2018 by the Ecological Society of America.

A simple approach to optimal control of invasive species.

PubMed

Hastings, Alan; Hall, Richard J; Taylor, Caz M

2006-12-01

The problem of invasive species and their control is one of the most pressing applied issues in ecology today. We developed simple approaches based on linear programming for determining the optimal removal strategies of different stage or age classes for control of invasive species that are still in a density-independent phase of growth. We illustrate the application of this method to the specific example of invasive Spartina alterniflora in Willapa Bay, WA. For all such systems, linear programming shows in general that the optimal strategy in any time step is to prioritize removal of a single age or stage class. The optimal strategy adjusts which class is the focus of control through time and can be much more cost effective than prioritizing removal of the same stage class each year.

Diversity-invasibility across an experimental disturbance gradient in Appalachian forests

Treesearch

R. Travis Belote; Robert H. Jones; Sharon M. Hood; Bryan W. Wender

2008-01-01

Research examining the relationship between community diversity and invasions by nonnative species has raised new questions about the theory and management of biological invasions. Ecological theory predicts, and small-scale experiments confirm, lower levels of nonnative species invasion into species-rich compared to species-poor communities, but observational studies...

Ecology and space: A case study in mapping harmful invasive species

USGS Publications Warehouse

David T. Barnett,; Jarnevich, Catherine S.; Chong, Geneva W.; Stohlgren, Thomas J.; Sunil Kumar,; Holcombe, Tracy R.; Brunn, Stanley D.; Dodge, Martin

2017-01-01

The establishment and invasion of non-native plant species have the ability to alter the composition of native species and functioning of ecological systems with financial costs resulting from mitigation and loss of ecological services. Spatially documenting invasions has applications for management and theory, but the utility of maps is challenged by availability and uncertainty of data, and the reliability of extrapolating mapped data in time and space. The extent and resolution of projections also impact the ability to inform invasive species science and management. Early invasive species maps were coarse-grained representations that underscored the phenomena, but had limited capacity to direct management aside from development of watch lists for priorities for prevention and containment. Integrating mapped data sets with fine-resolution environmental variables in the context of species-distribution models allows a description of species-environment relationships and an understanding of how, why, and where invasions may occur. As with maps, the extent and resolution of models impact the resulting insight. Models of cheatgrass (Bromus tectorum) across a variety of spatial scales and grain result in divergent species-environment relationships. New data can improve models and efficiently direct further inventories. Mapping can target areas of greater model uncertainty or the bounds of modeled distribution to efficiently refine models and maps. This iterative process results in dynamic, living maps capable of describing the ongoing process of species invasions.

Realized niche shift associated with the Eurasian charophyte Nitellopsis obtusa becoming invasive in North America

PubMed Central

Escobar, Luis E.; Qiao, Huijie; Phelps, Nicholas B. D.; Wagner, Carli K.; Larkin, Daniel J.

2016-01-01

Nitellopsis obtusa (starry stonewort) is a dioecious green alga native to Europe and Asia that has emerged as an aquatic invasive species in North America. Nitellopsis obtusa is rare across large portions of its native range, but has spread rapidly in northern-tier lakes in the United States, where it can interfere with recreation and may displace native species. Little is known about the invasion ecology of N. obtusa, making it difficult to forecast future expansion. Using ecological niche modeling we investigated environmental variables associated with invasion risk. We used species records, climate data, and remotely sensed environmental variables to characterize the species’ multidimensional distribution. We found that N. obtusa is exploiting novel ecological niche space in its introduced range, which may help explain its invasiveness. While the fundamental niche of N. obtusa may be stable, there appears to have been a shift in its realized niche associated with invasion in North America. Large portions of the United States are predicted to constitute highly suitable habitat for N. obtusa. Our results can inform early detection and rapid response efforts targeting N. obtusa and provide testable estimates of the physiological tolerances of this species as a baseline for future empirical research. PMID:27363541

The Icarus challenge - Predicting vulnerability to climate change using an algorithm-based species’ trait approach

EPA Science Inventory

Like Icarus, the world’s ecological resources are “flying too close” to the sun, and climate change will impact near-coastal species through temperature, sea-level rise, and ocean acidification and indirectly through changes in invasive species and land-use patt...

Cross-habitat effects shape the ecosystem consequences of co-invasion by a pelagic and a benthic consumer.

PubMed

Fryxell, David C; Diluzio, Amber R; Friedman, Maya A; Menge, Nicklaus A; Palkovacs, Eric P

2016-10-01

Invasive species can have major impacts on ecosystems, yet little work has addressed the combined effects of multiple invaders that exploit different habitats. Two common invaders in aquatic systems are pelagic fishes and crayfishes. Pelagic-oriented fish effects are typically strong on the pelagic food web, whereas crayfish effects are strong on the benthic food web. Thus, co-invasion may generate strong ecological responses in both habitats. We tested the effects of co-invasion on experimental pond ecosystems using two widespread invasive species, one pelagic (western mosquitofish) and one benthic (red swamp crayfish). As expected, mosquitofish had strong effects on the pelagic food web, reducing the abundance of Daphnia and causing a strong trophic cascade (increase in phytoplankton). Crayfish had strong effects on the benthic food web, reducing the abundance of benthic filamentous algae. Yet, we also found evidence for important cross-habitat effects. Mosquitofish treatments reduced the biomass of benthic filamentous algae, and crayfish treatments increased Daphnia and phytoplankton abundance. Combined effects of mosquitofish and crayfish were primarily positively or negatively additive, and completely offsetting for some responses, including gross primary production (GPP). Though co-invasion did not affect GPP, it strongly shifted primary production from the benthos into the water column. Effects on snail abundance revealed an interaction; snail abundance decreased only in the presence of both invaders. These results suggest that cross-habitat effects of co-invaders may lead to a variety of ecological outcomes; some of which may be unpredictable based on an understanding of each invader alone.

Invasive species and climate change (Chapter 7)

Treesearch

Justin B. Runyon; Jack L. Butler; Megan M. Friggens; Susan E. Meyer; Sharlene E. Sing

2012-01-01

Invasive species present one of the greatest threats to the health and sustainability of ecosystems worldwide. Invasive plants, animals, and diseases are known to have significant negative effects on biological diversity and the ecological structure and functions of native ecosystems. Moreover, the economic cost imposed by invasive species is enormous—the damage...

Multiple hypotheses testing of fish incidence patterns in an urbanized ecosystem

USGS Publications Warehouse

Chizinski, C.J.; Higgins, C.L.; Shavlik, C.E.; Pope, K.L.

2006-01-01

Ecological and evolutionary theories have focused traditionally on natural processes with little attempt to incorporate anthropogenic influences despite the fact that humans are such an integral part of virtually all ecosystems. A series of alternate models that incorporated anthropogenic factors and traditional ecological mechanisms of invasion to account for fish incidence patterns in urban lakes was tested. The models were based on fish biology, human intervention, and habitat characteristics. However, the only models to account for empirical patterns were those that included fish invasiveness, which incorporated species-specific information about overall tolerance and fecundity. This suggests that species-specific characteristics are more important in general distributional patterns than human-mediated dispersal. Better information of illegal stocking activities is needed to improve human-mediated models, and more insight into basic life history of ubiquitous species is needed to truly understand underlying mechanisms of biotic homogenization. ?? Springer 2005.

Genes, communities & invasive species: understanding the ecological and evolutionary dynamics of host-pathogen interactions.

PubMed

Burdon, J J; Thrall, P H; Ericson, L

2013-08-01

Reciprocal interactions between hosts and pathogens drive ecological, epidemiological and co-evolutionary trajectories, resulting in complex patterns of diversity at population, species and community levels. Recent results confirm the importance of negative frequency-dependent rather than 'arms-race' processes in the evolution of individual host-pathogen associations. At the community level, complex relationships between species abundance and diversity dampen or alter pathogen impacts. Invasive pathogens challenge these controls reflecting the earliest stages of evolutionary associations (akin to arms-race) where disease effects may be so great that they overwhelm the host's and community's ability to respond. Viewing these different stabilization/destabilization phases as a continuum provides a valuable perspective to assessment of the role of genetics and ecology in the dynamics of both natural and invasive host-pathogen associations. Copyright © 2013 Elsevier Ltd. All rights reserved.

Identity, reproductive potential, distribution, ecology and management of invasive Pomacea maculata in the southern United States

USGS Publications Warehouse

Burks, Romi L.; Bernatis, Jennifer; Byers, James E.; Carter, Jacoby; Martin, Charles M.; McDowell, William G.; Van Dyke, Jess; Joshi, R. C.; Cowie, R. H.; Sebastian, L. S.

2017-01-01

evidence. However, the two species are often still confused because of their similar shell morphologies and life history traits. This contribution reviews the distribution, life history, ecology and management of P. maculata introduced to the southern USA. So far the agricultural impacts of P. maculata in the USA fail to match those of non-native applesnails elsewhere, but the invasion of wetlands by this species suggests the need for increased vigilance to prevent further spread and avoid the ecological impacts that have been associated elsewhere with P. canaliculata.

Ecological Exposure Research: Water

EPA Pesticide Factsheets

Overview of ecological exposure water research, including invasive species, Functional Process Zones (FPZs), biomarkers, pharmaceuticals in water, headwater streams, DNA barcoding, wetland ecosystem services, and sediment remediation.

Ecological niche transferability using invasive species as a case study.

PubMed

Fernández, Miguel; Hamilton, Healy

2015-01-01

Species distribution modeling is widely applied to predict invasive species distributions and species range shifts under climate change. Accurate predictions depend upon meeting the assumption that ecological niches are conserved, i.e., spatially or temporally transferable. Here we present a multi-taxon comparative analysis of niche conservatism using biological invasion events well documented in natural history museum collections. Our goal is to assess spatial transferability of the climatic niche of a range of noxious terrestrial invasive species using two complementary approaches. First we compare species' native versus invasive ranges in environmental space using two distinct methods, Principal Components Analysis and Mahalanobis distance. Second we compare species' native versus invaded ranges in geographic space as estimated using the species distribution modeling technique Maxent and the comparative index Hellinger's I. We find that species exhibit a range of responses, from almost complete transferability, in which the invaded niches completely overlap with the native niches, to a complete dissociation between native and invaded ranges. Intermediate responses included expansion of dimension attributable to either temperature or precipitation derived variables, as well as niche expansion in multiple dimensions. We conclude that the ecological niche in the native range is generally a poor predictor of invaded range and, by analogy, the ecological niche may be a poor predictor of range shifts under climate change. We suggest that assessing dimensions of niche transferability prior to standard species distribution modeling may improve the understanding of species' dynamics in the invaded range.

Proceedings, 22nd U.S. Department of Agriculture interagency research forum on invasive species 2011

Treesearch

Katherine A McManus; Kurt W., eds. Gottschalk

2011-01-01

Contains abstracts and papers of 62 oral and poster presentations on invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Research Forum on Invasive Species.

Proceedings 19th U.S. Department of Agriculture Interagency Research Forum on Invasive Species 2008

Treesearch

Katherine A. McManus; Kurt W., eds. Gottschalk

2009-01-01

Contains abstracts and papers of 67 oral and poster presentations on invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Research Forum on Invasive Species.

Proceedings, 21st U.S. Department of Agriculture interagency research forum on invasive species 2010

Treesearch

Katherine A McManus; Kurt W. Gottschalk

2010-01-01

Contains abstracts and papers of 95 oral and poster presentations on invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Research Forum on Invasive Species.

Proceedings, 23rd U.S. Department of Agriculture interagency research forum on invasive species 2012

Treesearch

Katherine A McManus; Kurt W., eds. Gottschalk

2013-01-01

Contains abstracts and papers of 75 oral and poster presentations on invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Research Forum on Invasive Species.

DNA barcoding of invasive plants in China: A resource for identifying invasive plants.

PubMed

Xu, Song-Zhi; Li, Zhen-Yu; Jin, Xiao-Hua

2018-01-01

Invasive plants have aroused attention globally for causing ecological damage and having a negative impact on the economy and human health. However, it can be extremely challenging to rapidly and accurately identify invasive plants based on morphology because they are an assemblage of many different families and many plant materials lack sufficient diagnostic characteristics during border inspections. It is therefore urgent to evaluate candidate loci and build a reliable genetic library to prevent invasive plants from entering China. In this study, five common single markers (ITS, ITS2, matK, rbcL and trnH-psbA) were evaluated using 634 species (including 469 invasive plant species in China, 10 new records to China, 16 potentially invasive plant species around the world but not introduced into China yet and 139 plant species native to China) based on three different methods. Our results indicated that ITS2 displayed largest intra- and interspecific divergence (1.72% and 91.46%). Based on NJ tree method, ITS2, ITS, matK, rbcL and trnH-psbA provided 76.84%, 76.5%, 63.21%, 52.86% and 50.68% discrimination rates, respectively. The combination of ITS + matK performed best and provided 91.03% discriminatory power, followed by ITS2 + matK (85.78%). For identifying unknown individuals, ITS + matK had 100% correct identification rate based on our database, followed by ITS/ITS2 (both 93.33%) and ITS2 + matK (91.67%). Thus, we propose ITS/ITS2 + matK as the most suitable barcode for invasive plants in China. This study also demonstrated that DNA barcoding is an efficient tool for identifying invasive species. © 2017 John Wiley & Sons Ltd.

Effects of invasive plants on arthropods.

PubMed

Litt, Andrea R; Cord, Erin E; Fulbright, Timothy E; Schuster, Greta L

2014-12-01

Non-native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer-reviewed literature to evaluate responses of arthropod communities and functional groups to non-native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty-two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web-building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to ecological change, arthropods may be ideal targets for restoration and conservation activities. © 2014 Society for Conservation Biology.

Limiting similarity and Darwin's naturalization hypothesis: understanding the drivers of biotic resistance against invasive plant species.

PubMed

Yannelli, F A; Koch, C; Jeschke, J M; Kollmann, J

2017-03-01

Several hypotheses have been proposed to explain biotic resistance of a recipient plant community based on reduced niche opportunities for invasive alien plant species. The limiting similarity hypothesis predicts that invasive species are less likely to establish in communities of species holding similar functional traits. Likewise, Darwin's naturalization hypothesis states that invasive species closely related to the native community would be less successful. We tested both using the invasive alien Ambrosia artemisiifolia L. and Solidago gigantea Aiton, and grassland species used for ecological restoration in central Europe. We classified all plant species into groups based on functional traits obtained from trait databases and calculated the phylogenetic distance among them. In a greenhouse experiment, we submitted the two invasive species at two propagule pressures to competition with communities of ten native species from the same functional group. In another experiment, they were submitted to pairwise competition with native species selected from each functional group. At the community level, highest suppression for both invasive species was observed at low propagule pressure and not explained by similarity in functional traits. Moreover, suppression decreased asymptotically with increasing phylogenetic distance to species of the native community. When submitted to pairwise competition, suppression for both invasive species was also better explained by phylogenetic distance. Overall, our results support Darwin's naturalization hypothesis but not the limiting similarity hypothesis based on the selected traits. Biotic resistance of native communities against invasive species at an early stage of establishment is enhanced by competitive traits and phylogenetic relatedness.

NEON: the first continental-scale ecological observatory with airborne remote sensing of vegetation canopy biochemistry and structure

Treesearch

Thomas U. Kampe; Brian R. Johnson; Michele Kuester; Michael Keller

2010-01-01

The National Ecological Observatory Network (NEON) is an ecological observation platform for discovering, understanding and forecasting the impacts of climate change, land use change, and invasive species on continental-scale ecology. NEON will operate for 30 years and gather long-term data on ecological response changes and on feedbacks with the geosphere, hydrosphere...

The need for spatially explicit quantification of benefits in invasive-species management.

PubMed

Januchowski-Hartley, Stephanie R; Adams, Vanessa M; Hermoso, Virgilio

2018-04-01

Worldwide, invasive species are a leading driver of environmental change across terrestrial, marine, and freshwater environments and cost billions of dollars annually in ecological damages and economic losses. Resources limit invasive-species control, and planning processes are needed to identify cost-effective solutions. Thus, studies are increasingly considering spatially variable natural and socioeconomic assets (e.g., species persistence, recreational fishing) when planning the allocation of actions for invasive-species management. There is a need to improve understanding of how such assets are considered in invasive-species management. We reviewed over 1600 studies focused on management of invasive species, including flora and fauna. Eighty-four of these studies were included in our final analysis because they focused on the prioritization of actions for invasive species management. Forty-five percent (n = 38) of these studies were based on spatial optimization methods, and 35% (n = 13) accounted for spatially variable assets. Across all 84 optimization studies considered, 27% (n = 23) explicitly accounted for spatially variable assets. Based on our findings, we further explored the potential costs and benefits to invasive species management when spatially variable assets are explicitly considered or not. To include spatially variable assets in decision-making processes that guide invasive-species management there is a need to quantify environmental responses to invasive species and to enhance understanding of potential impacts of invasive species on different natural or socioeconomic assets. We suggest these gaps could be filled by systematic reviews, quantifying invasive species impacts on native species at different periods, and broadening sources and enhancing sharing of knowledge. © 2017 Society for Conservation Biology.

Invasive plant species and the Joint Fire Science Program.

Treesearch

Heather E. Erickson; Rachel White

2007-01-01

Invasive nonnative plants may be responsible for serious, long-term ecological impacts, including altering fire behavior and fire regimes. Therefore, knowing how to successfully manage invasive plants and their impacts on natural resources is crucial. We present a summary of research on invasive plants and fire that has been generated through the Joint Fire Science...

Chapter 2: Effects of fire on nonnative invasive plants and invasibility of wildland ecosystems

Treesearch

Kristin Zouhar; Jane Kapler Smith; Steve Sutherland

2008-01-01

Considerable experimental and theoretical work has been done on general concepts regarding nonnative species and disturbance, but experimental research on the effects of fire on nonnative invasive species is sparse. We begin this chapter by connecting fundamental concepts from the literature of invasion ecology to fire. Then we examine fire behavior characteristics,...

A two-part measure of degree of invasion for cross-community comparisons

Treesearch

Qinfeng Guo; Amy Symstad

2008-01-01

Invasibility is a critical feature of ecological communities, especially for management decisions. To date, invasibility has been measured in numerous ways. Although most researchers have used the richness (or number) of exotic species as a direct or indirect measure of community invasibility, others have used alternative measures such as the survival, density, or...

Ecological and economic determinants of invasive tree species on Alabama forestland

Treesearch

Anwar Hussain; Changyou Sun; Xiaoping Zhou; Ian A. Munn

2008-01-01

The spread of invasive tree species has caused increasing harm to the environment. This study was motivated by the considerations that earlier studies generally ignored the role of economic factors related to the occurrence and abundance of invasive species, and empirical analyses of invasive trees on forestland have been inadequate. We assessed the impact of...

Reconciling an invasive plant’s role in aquatic food webs: a case study of an adaptive management process for water hyacinth

USDA-ARS?s Scientific Manuscript database

1. Globally, invasive species have a multitude of ecological and socio-economic impacts. However, invasive species can provide novel structure and habitat for native species. The growing rate of biological invasions world-wide presents an urgent dilemma: how can natural resource managers minimize ne...

Proposed BMPs for Invasive Plant Mitigation during Timber Harvesting Operations

Treesearch

Chris B. LeDoux; Danielle K. Martin

2013-01-01

The invasion and spread of invasive plants is a major problem in forested ecosystems. Invasive plants can displace existing vegetation and in some cases take over the site. With the displacement of native vegetation come major ecosystem changes that may jeopardize ecological processes and functions as well as habitat for wildlife. The disturbance caused during timber...

Differential invasion success of salmonids in southern Chile: patterns and hypotheses

Treesearch

Ivan Arismendi; Brooke E. Penaluna; Jason B. Dunham; Carlos Garcia de Leaniz; Doris Soto; Ian A. Fleming; Daniel Gomez-Uchida; Gonzalo Gajardo; Pamela V. Varga; Jorge León-Muñoz

2014-01-01

Biological invasions create complex ecological and societal issues worldwide. Most of the knowledge about invasions comes only from successful invaders, but less is known about which processes determine the differential success of invasions. In this review, we develop a framework to identify the main dimensions driving the success and failure of invaders, including...

Predator-Free New Zealand: Conservation Country.

PubMed

Russell, James C; Innes, John G; Brown, Philip H; Byrom, Andrea E

2015-05-01

Eradications of invasive species from over 1000 small islands around the world have created conservation arks, but to truly address the threat of invasive species to islands, eradications must be scaled by orders of magnitude. New Zealand has eradicated invasive predators from 10% of its offshore island area and now proposes a vision to eliminate them from the entire country. We review current knowledge of invasive predator ecology and control technologies in New Zealand and the biological research, technological advances, social capacity and enabling policy required. We discuss the economic costs and benefits and conclude with a 50-year strategy for a predator-free New Zealand that is shown to be ecologically obtainable, socially desirable, and economically viable. The proposal includes invasive predator eradication from the two largest offshore islands, mammal-free mainland peninsulas, very large ecosanctuaries, plus thousands of small projects that will together merge eradication and control concepts on landscape scales.

Predator-Free New Zealand: Conservation Country

PubMed Central

Russell, James C.; Innes, John G.; Brown, Philip H.; Byrom, Andrea E.

2015-01-01

Eradications of invasive species from over 1000 small islands around the world have created conservation arks, but to truly address the threat of invasive species to islands, eradications must be scaled by orders of magnitude. New Zealand has eradicated invasive predators from 10% of its offshore island area and now proposes a vision to eliminate them from the entire country. We review current knowledge of invasive predator ecology and control technologies in New Zealand and the biological research, technological advances, social capacity and enabling policy required. We discuss the economic costs and benefits and conclude with a 50-year strategy for a predator-free New Zealand that is shown to be ecologically obtainable, socially desirable, and economically viable. The proposal includes invasive predator eradication from the two largest offshore islands, mammal-free mainland peninsulas, very large ecosanctuaries, plus thousands of small projects that will together merge eradication and control concepts on landscape scales. PMID:26955079

Mapping invasive weeds using airborne hyperspectral imagery

USDA-ARS?s Scientific Manuscript database

Invasive plant species present a serious problem to the natural environment and have adverse ecological and economic impacts on both terrestrial and aquatic ecosystems they invade. This article provides a brief overview on the use of remote sensing for mapping invasive plant species in both terrestr...

Ecology, genetics, and biological control of invasive annual grasses in the Great Basin

USDA-ARS?s Scientific Manuscript database

Several annual grass species native to Eurasia, including cheatgrass (Bromus tectorum), red brome (B. rubens), and medusahead (Taeniatherum caput-medusae) have become invasive in the western USA. These invasive species degrade rangelands by compromising forage, outcompeting native flora, and exacerb...

Spatial dynamics of the vegetation community associated with an invasive emergent macrophyte in a regulated river.

USDA-ARS?s Scientific Manuscript database

Successful management of riverine ecosystems often requires mitigation of alien plant invasions. Understanding how environmental variation within watersheds influences distribution and spread of invasive plants is essential to restoring impacted ecological functions and conserving native plant commu...

Clonal spread of invasive Ludwigia hexapetala and L. grandiflora in freshwater wetlands of California

USDA-ARS?s Scientific Manuscript database

Determining the reproductive mode contributing to dispersal within and between populations of invasive species is essential to understand the ecological and evolutionary processes underlying invasions and to guide management strategies. Ludwigia hexapetala and L. grandiflora are emergent aquatic sp...

Genetic analysis reveals multiple cryptic invasive species of the hydrozoan gene Cordylophora

EPA Science Inventory

Understanding the patterns and dynamics of biological invasions is a crucial prerequisite to predicting and mitigating their potential ecological and economic impacts. Unfortunately, in many cases such understanding is limited not only by ignorance of invasion history, but also b...

Government success in partnership: the USDA-ARS area-wide ecologically based invasive annual grass management program

USDA-ARS?s Scientific Manuscript database

As new research is conducted and new methods for solving problems are developed, the USDAARS has a program that allocates substantial funding to ensure these improved strategies and techniques are adopted by those who can benefit from them. These programs are called Area-wide demonstrations. A partn...

The value of decision models: Using ecologically based invasive plant management as an example

USDA-ARS?s Scientific Manuscript database

Humans have both fast and slow thought processes which influence our judgment and decision-making. The fast system is intuitive and valuable for decisions which do not require multiple steps or the application of logic or statistics. However, many decisions in natural resources are complex and req...

Metabolite profiling of fish skin mucus: a novel approach for minimally-invasive environmental exposure monitoring and surveillance.

PubMed

Ekman, D R; Skelton, D M; Davis, J M; Villeneuve, D L; Cavallin, J E; Schroeder, A; Jensen, K M; Ankley, G T; Collette, T W

2015-03-03

The application of 'omics tools to biologically based monitoring and surveillance of aquatic environments shows considerable promise for complementing chemical monitoring in ecological risk assessments. However, few of the current approaches offer the ability to sample ecologically relevant species (e.g., fish) in a way that produces minimal impact on the health of the organism(s) under study. In the current study we employ liquid chromatography tandem mass spectrometry (LC-MS/MS) to assess the potential for skin mucus-based metabolomics for minimally invasive sampling of the fathead minnow (FHM; Pimephales promelas). Using this approach we were able to detect 204 distinct metabolites in the FHM skin mucus metabolome representing a large number of metabolite classes. An analysis of the sex specificity of the skin mucus metabolome showed it to be highly sexually dimorphic with 72 of the detected metabolites showing a statistically significant bias with regard to sex. Finally, in a proof-of-concept fashion we report on the use of skin mucus-based metabolomics to assess exposures in male and female fathead minnows to an environmentally relevant concentration of bisphenol A, a nearly ubiquitous environmental contaminant and an established endocrine active chemical.

Density dependence in demography and dispersal generates fluctuating invasion speeds

PubMed Central

Li, Bingtuan; Miller, Tom E. X.

2017-01-01

Density dependence plays an important role in population regulation and is known to generate temporal fluctuations in population density. However, the ways in which density dependence affects spatial population processes, such as species invasions, are less understood. Although classical ecological theory suggests that invasions should advance at a constant speed, empirical work is illuminating the highly variable nature of biological invasions, which often exhibit nonconstant spreading speeds, even in simple, controlled settings. Here, we explore endogenous density dependence as a mechanism for inducing variability in biological invasions with a set of population models that incorporate density dependence in demographic and dispersal parameters. We show that density dependence in demography at low population densities—i.e., an Allee effect—combined with spatiotemporal variability in population density behind the invasion front can produce fluctuations in spreading speed. The density fluctuations behind the front can arise from either overcompensatory population growth or density-dependent dispersal, both of which are common in nature. Our results show that simple rules can generate complex spread dynamics and highlight a source of variability in biological invasions that may aid in ecological forecasting. PMID:28442569

GSD Update: What are invasive species? ... And do we really need to worry about them?

Treesearch

Catherine Dold

2011-01-01

Invasive species are the focus of the September 2011 issue of GSDUpdate: What Are Invasive Species? And Do We Really Need to Worry About Them? An invasive species is any species - non-native or native to a region - that could cause economic or ecological harm to an area. Invasives can be weeds, shrubs and trees, insects, mollusks, vertebrates and even microorganisms...

The effect of invasive hybrid taxa on the ecological succession of coastal marshes

USDA-ARS?s Scientific Manuscript database

Hybridization following colonization of invasive species in novel environments frequently results in offspring with improved biological and competitive functions referred to as heterosis or hybrid vigor. However, little is known about the effect of these invasive hybrids on the structuring and funct...

Ecological correlates of invasion impact for Burmese pythons in Florida

USGS Publications Warehouse

Reed, R.N.; Willson, J.D.; Rodda, G.H.; Dorcas, M.E.

2012-01-01

An invasive population of Burmese pythons (Python molurus bivittatus) is established across several thousand square kilometers of southern Florida and appears to have caused precipitous population declines among several species of native mammals. Why has this giant snake had such great success as an invasive species when many established reptiles have failed to spread? We scored the Burmese python for each of 15 literature-based attributes relative to predefined comparison groups from a diverse range of taxa and provide a review of the natural history and ecology of Burmese pythons relevant to each attribute. We focused on attributes linked to spread and magnitude of impacts rather than establishment success. Our results suggest that attributes related to body size and generalism appeared to be particularly applicable to the Burmese python's success in Florida. The attributes with the highest scores were: high reproductive potential, low vulnerability to predation, large adult body size, large offspring size and high dietary breadth. However, attributes of ectotherms in general and pythons in particular (including predatory mode, energetic efficiency and social interactions) might have also contributed to invasion success. Although establishment risk assessments are an important initial step in prevention of new establishments, evaluating species in terms of their potential for spreading widely and negatively impacting ecosystems might become part of the means by which resource managers prioritize control efforts in environments with large numbers of introduced species.

Episodic processes, invasion and faunal mosaics in evolutionary and ecological time

USDA-ARS?s Scientific Manuscript database

Episodes of ecological perturbation and faunal turnover represent crises for global biodiversity and have occurred periodically across Earth history on a continuum linking deep evolutionary and shallow ecological time. Major extinction events and biodiversity crises across the 540 milion years of th...

An ecological risk assessment of nonnative boas and pythons as potentially invasive species in the United States.

PubMed

Reed, Robert N

2005-06-01

The growing international trade in live wildlife has the potential to result in continuing establishment of nonnative animal populations in the United States. Snakes may pose particularly high risks as potentially invasive species, as exemplified by the decimation of Guam's vertebrate fauna by the accidentally introduced brown tree snake. Herein, ecological and commercial predictors of the likelihood of establishment of invasive populations were used to model risk associated with legal commercial imports of 23 species of boas, pythons, and relatives into the United States during the period 1989-2000. Data on ecological variables were collected from multiple sources, while data on commercial variables were collated from import records maintained by the U.S. Fish and Wildlife Service. Results of the risk-assessment models indicate that species including boa constrictors (Boa constrictor), ball pythons (Python regius), and reticulated pythons (P. reticulatus) may pose particularly high risks as potentially invasive species. Recommendations for reducing risk of establishment of invasive populations of snakes and/or pathogens include temporary quarantine of imports to increase detection rates of nonnative pathogens, increasing research attention to reptile pathogens, reducing the risk that nonnative snakes will reach certain areas with high numbers of federally listed species (such as the Florida Keys), and attempting to better educate individuals purchasing reptiles.

Should we expect population thresholds for wildlife disease?

USGS Publications Warehouse

Lloyd-Smith, James O.; Cross, P.C.; Briggs, C.J.; Daugherty, M.; Getz, W.M.; Latto, J.; Sanchez, M.; Smith, A.; Swei, A.

2005-01-01

Host population thresholds for invasion or persistence of infectious disease are core concepts of disease ecology, and underlie on-going and controversial disease control policies based on culling and vaccination. Empirical evidence for these thresholds in wildlife populations has been sparse, however, though recent studies have narrowed this gap. Here we review the theoretical bases for population thresholds for disease, revealing why they are difficult to measure and sometimes are not even expected, and identifying important facets of wildlife ecology left out of current theories. We discuss strengths and weaknesses of selected empirical studies that have reported disease thresholds for wildlife, identify recurring obstacles, and discuss implications of our imperfect understanding of wildlife thresholds for disease control policy.

Mating disruption by aerial application of sex pheromone against the invasive light brown apple moth and implications for the management of biological invasions

USDA-ARS?s Scientific Manuscript database

Biological invasions resulting from international trade can have major ecological and economic impacts. Eradication can be a viable strategy during the early stage of an invasion but there is a need for the development of suitable tactics that are both effective and have minimal non-target effects. ...

Invasive Species Guidebook for Department of Defense Installations in the Delaware River Basin: Identification, Control, and Restoration

DTIC Science & Technology

2009-06-01

155 SECTION II: PREVENTING RECURRING INVASIVE SPECIES AND RESTORING HISTORICAL PLANT COMMUNITIES ...Wilcove et al. 1998, Westbrook et al. 2005). Beyond degradation to ecological communities , invasive species can threaten human health and cause...recurrence of problem invasive species. This section also gives recommendations for returning management areas to historical native plant communities

Improving management of nonnative invasive plants in wilderness and other natural areas

Treesearch

John M. Randall

2000-01-01

Nonnative invasive plants invade wilderness and other natural areas throughout North America and invasive organisms as a group are now considered the second worst threat to biodiversity, behind only habitat loss and fragmentation. In the past 10-20 years there have been upsurges in interest in the ecology of plant invasions among researchers and in concern about how to...

Impacts of Climate Change on the Global Invasion Potential of the African Clawed Frog Xenopus laevis

PubMed Central

Ihlow, Flora; Courant, Julien; Secondi, Jean; Herrel, Anthony; Rebelo, Rui; Measey, G. John; Lillo, Francesco; De Villiers, F. André; Vogt, Solveig; De Busschere, Charlotte; Backeljau, Thierry; Rödder, Dennis

2016-01-01

By altering or eliminating delicate ecological relationships, non-indigenous species are considered a major threat to biodiversity, as well as a driver of environmental change. Global climate change affects ecosystems and ecological communities, leading to changes in the phenology, geographic ranges, or population abundance of several species. Thus, predicting the impacts of global climate change on the current and future distribution of invasive species is an important subject in macroecological studies. The African clawed frog (Xenopus laevis), native to South Africa, possesses a strong invasion potential and populations have become established in numerous countries across four continents. The global invasion potential of X. laevis was assessed using correlative species distribution models (SDMs). SDMs were computed based on a comprehensive set of occurrence records covering South Africa, North America, South America and Europe and a set of nine environmental predictors. Models were built using both a maximum entropy model and an ensemble approach integrating eight algorithms. The future occurrence probabilities for X. laevis were subsequently computed using bioclimatic variables for 2070 following four different IPCC scenarios. Despite minor differences between the statistical approaches, both SDMs predict the future potential distribution of X. laevis, on a global scale, to decrease across all climate change scenarios. On a continental scale, both SDMs predict decreasing potential distributions in the species’ native range in South Africa, as well as in the invaded areas in North and South America, and in Australia where the species has not been introduced. In contrast, both SDMs predict the potential range size to expand in Europe. Our results suggest that all probability classes will be equally affected by climate change. New regional conditions may promote new invasions or the spread of established invasive populations, especially in France and Great Britain. PMID:27248830

Impacts of Climate Change on the Global Invasion Potential of the African Clawed Frog Xenopus laevis.

PubMed

Ihlow, Flora; Courant, Julien; Secondi, Jean; Herrel, Anthony; Rebelo, Rui; Measey, G John; Lillo, Francesco; De Villiers, F André; Vogt, Solveig; De Busschere, Charlotte; Backeljau, Thierry; Rödder, Dennis

2016-01-01

By altering or eliminating delicate ecological relationships, non-indigenous species are considered a major threat to biodiversity, as well as a driver of environmental change. Global climate change affects ecosystems and ecological communities, leading to changes in the phenology, geographic ranges, or population abundance of several species. Thus, predicting the impacts of global climate change on the current and future distribution of invasive species is an important subject in macroecological studies. The African clawed frog (Xenopus laevis), native to South Africa, possesses a strong invasion potential and populations have become established in numerous countries across four continents. The global invasion potential of X. laevis was assessed using correlative species distribution models (SDMs). SDMs were computed based on a comprehensive set of occurrence records covering South Africa, North America, South America and Europe and a set of nine environmental predictors. Models were built using both a maximum entropy model and an ensemble approach integrating eight algorithms. The future occurrence probabilities for X. laevis were subsequently computed using bioclimatic variables for 2070 following four different IPCC scenarios. Despite minor differences between the statistical approaches, both SDMs predict the future potential distribution of X. laevis, on a global scale, to decrease across all climate change scenarios. On a continental scale, both SDMs predict decreasing potential distributions in the species' native range in South Africa, as well as in the invaded areas in North and South America, and in Australia where the species has not been introduced. In contrast, both SDMs predict the potential range size to expand in Europe. Our results suggest that all probability classes will be equally affected by climate change. New regional conditions may promote new invasions or the spread of established invasive populations, especially in France and Great Britain.

Wildland fire in ecosystems: fire and nonnative invasive plants

Treesearch

Kristin Zouhar; Jane Kapler Smith; Steve Sutherland; Matthew L. Brooks

2008-01-01

This state-of-knowledge review of information on relationships between wildland fire and nonnative invasive plants can assist fire managers and other land managers concerned with prevention, detection, and eradication or control of nonnative invasive plants. The 16 chapters in this volume synthesize ecological and botanical principles regarding relationships between...

Invasive aquatic vegetation management in the Sacramento-San Joaquin River Delta: status recommendations

USDA-ARS?s Scientific Manuscript database

Widespread growth of invasive aquatic vegetation is a major stressor to the Sacramento-San Joaquin River Delta, a region of significant agricultural, industrial, and ecological importance. Total invaded area in the Delta is increasing, with the risk of new invasions a continual threat. However, inva...

Globalization and Invasive Species Issues in Hawaii: Role-Playing Some Local Perspectives

ERIC Educational Resources Information Center

Fox, Alison M.; Loope, Lloyd L.

2007-01-01

Increasingly recognized as having significant economic and ecological impacts, non-native invasive species have become an important interdisciplinary topic in biological and social science courses. Oceanic island systems like Hawaii have been particularly susceptible to invaders and efforts to prevent further invasions focus on reducing the…

V. Terrestrial vertebrates

Treesearch

Dean Pearson; Deborah Finch

2011-01-01

Within the Interior West, terrestrial vertebrates do not represent a large number of invasive species relative to invasive weeds, aquatic vertebrates, and invertebrates. However, several invasive terrestrial vertebrate species do cause substantial economic and ecological damage in the U.S. and in this region (Pimental 2000, 2007; Bergman and others 2002; Finch and...

Book review: Encyclopedia of biological invasions

Treesearch

Qinfeng Guo

2011-01-01

Species introductions and consequent biotic invasions and homogenization are major components of global change that are drawing increasing concern and various levels of actions and reactions around the world. Invasion ecology has advanced rapidly during the last few decades, and the discipline is now increasingly integrated with the social and economic sciences. A...

78 FR 70317 - Invasive Species Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-25

... and providing for their control and minimizing the economic, ecological, and human health impacts that..., modification and adoption of an ISAC position paper on utilizing harvest incentives to control invasive species...

Genetic Relationships among Invasive Hydrilla (Hydrilla verticillata L.f. Royle) Biotypes in the US and Their Implications for Management

DTIC Science & Technology

2014-02-01

Orians, C. M. 2000. The effects of hybridization in plants on secondary chemistry: Implications for the ecology and evolution of plant -herbivore...2011). Experimental crosses have revealed that female dioecious plants in Florida are potentially fertile and can produce viable seed when pollinated by...nonindigenous invasive plant hydrilla (Hydrilla verticillata). Molecular Ecology 13:3229-3237. Moody, M. L., D. H. Les. 2002. Evidence of hybridity in

Rapidly spreading seagrass invades the Caribbean with unknown ecological consequences

USGS Publications Warehouse

Rogers, Caroline S.; Willette, Demian A; Miller, Jeff

2014-01-01

The non-native seagrass Halophila stipulacea has spread rapidly throughout the Caribbean Sea (Willette et al. 2014); without additional research, the ecological ramifications of this invasion are difficult to predict. Biodiversity, connectivity of marine ecosystems, and recovery of degraded coral reefs could all be affected. The invasive seagrass, native to the Red Sea and Indian Ocean, has taken over sand bottoms and intermixed with or replaced native seagrasses, including Thalassia testudinum, Syringodium filiforme, and Halodule wrightii.

Co-introduction vs ecological fitting as pathways to the establishment of effective mutualisms during biological invasions.

PubMed

Le Roux, Johannes J; Hui, Cang; Keet, Jan-Hendrik; Ellis, Allan G

2017-09-01

Contents 1354 I. 1354 II. 1355 III. 1357 IV. 1357 V. 1359 1359 References 1359 SUMMARY: Interactions between non-native plants and their mutualists are often disrupted upon introduction to new environments. Using legume-rhizobium mutualistic interactions as an example, we discuss two pathways that can influence symbiotic associations in such situations: co-introduction of coevolved rhizobia; and utilization of, and adaptation to, resident rhizobia, hereafter referred to as 'ecological fitting'. Co-introduction and ecological fitting have distinct implications for successful legume invasions and their impacts. Under ecological fitting, initial impacts may be less severe and will accrue over longer periods as novel symbiotic associations and/or adaptations may require fine-tuning over time. Co-introduction will have more profound impacts that will accrue more rapidly as a result of positive feedbacks between densities of non-native rhizobia and their coevolved host plants, in turn enhancing competition between native and non-native rhizobia. Co-introduction can further impact invasion outcomes by the exchange of genetic material between native and non-native rhizobia, potentially resulting in decreased fitness of native legumes. A better understanding of the roles of these two pathways in the invasion dynamics of non-native legumes is much needed, and we highlight some of the exciting research avenues it presents. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

"Blame it on the weeds": politics, poverty, and ecology in the new South Africa.

PubMed

Neely, Abigail H

2010-01-01

In January of 2000, spectacular fires burned in the natural veld of Cape Town, South Africa. As the fire-fighting effort finished, a theory emerged: invasive alien species, trees from other countries, such as Australia and the United States, were to blame for the fires. While the invasive alien hypothesis captured the attention of media and policy makers alike, there was little ecological evidence to support it. This article places the fires of 2000 in a longer history of post-apartheid policy and science surrounding invasive alien floral species, arguing that the fires allowed for a synergy between concerns over poverty relief, nature conservation, and scientific research. The most visible example of this synergy was an increased commitment to the Working for Water programme on the Cape Peninsula, a large-scale employment programme utilising unskilled labour to clear invasive alien species in order to conserve South African water resources. In addition to providing employment for South Africa's poorest citizens, Working for Water provided funding for ecological research about invasive alien species. The studies that resulted from this funding focused on gathering information to make practical suggestions for invasive species control. Although the focus of these studies was on management, the science used was itself as rigorous as it had ever been. In the post-apartheid era, as poverty relief and nature conservation came together, scientists ensured that they would continue to play a role in nature conservation by making their research relevant to both invasive species control and to poverty relief.

Ecological consequences of invasion across the freshwater-marine transition in a warming world.

PubMed

Crespo, Daniel; Solan, Martin; Leston, Sara; Pardal, Miguel A; Dolbeth, Marina

2018-02-01

The freshwater-marine transition that characterizes an estuarine system can provide multiple entry options for invading species, yet the relative importance of this gradient in determining the functional contribution of invading species has received little attention. The ecological consequences of species invasion are routinely evaluated within a freshwater versus marine context, even though many invasive species can inhabit a wide range of salinities. We investigate the functional consequences of different sizes of Corbicula fluminea -an invasive species able to adapt to a wide range of temperatures and salinity-across the freshwater-marine transition in the presence versus absence of warming. Specifically, we characterize how C. fluminea affect fluid and particle transport, important processes in mediating nutrient cycling (NH 4 -N, NO 3 -N, PO 4 -P). Results showed that sediment particle reworking (bioturbation) tends to be influenced by size and to a lesser extent, temperature and salinity; nutrient concentrations are influenced by different interactions between all variables (salinity, temperature, and size class). Our findings demonstrate the highly context-dependent nature of the ecosystem consequences of invasion and highlight the potential for species to simultaneously occupy multiple components of an ecosystem. Recognizing of this aspect of invasibility is fundamental to management and conservation efforts, particularly as freshwater and marine systems tend to be compartmentalized rather than be treated as a contiguous unit. We conclude that more comprehensive appreciation of the distribution of invasive species across adjacent habitats and different seasons is urgently needed to allow the true extent of biological introductions, and their ecological consequences, to be fully realized.

Land Management in the Anthropocene: Is History Still Relevant?

NASA Astrophysics Data System (ADS)

Safford, Hugh D.; Betancourt, Julio L.; Hayward, Gregory D.; Wiens, John A.; Regan, Claudia M.

2008-09-01

Incorporating Historical Ecology and Climate Change Into Land Management; Lansdowne, Virginia, 22-25 April 2008; Ecological restoration, conservation, and land management are often based on comparisons with reference sites or time periods, which are assumed to represent ``natural'' or ``properly functioning'' conditions. Such reference conditions can provide a vision of the conservation or management goal and a means to measure progress toward that vision. Although historical ecology has been used successfully to guide resource management in many parts of the world, the continuing relevance of history is now being questioned. Some scientists doubt that lessons from the past can inform management in what may be a dramatically different future, given profound climate change, accelerated land use, and an onslaught of plant and animal invasions.

Abundance of introduced species at home predicts abundance away in herbaceous communities

Treesearch

J. Firn; J.L. Moore; A.S. MacDougall; E.T. Borer; E.W. Seabloom; J. HilleRisLambers; S. Harpole; E.E. Cleland; C.S. Brown; J.M.H. Knops; S.M. Prober; D.A. Pyke; K.A. Farrell; J.D. Bakker; L.R. O’Halloran; P.B. Adler; S.L. Collins; C.M. D’Antonio; M.J. Crawley; E.M. Wolkovich; K.J. La Pierre; B.A. Melbourne; Y. Hautier; J.W. Morgan; A.D.B. Leakey; A.D. Kay; R.L. McCulley; K.F. Davies; C.J. Stevens; C.J. Chu

2011-01-01

Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at...

AN ECOLOGICAL ASSESSMENT OF INVASIVE AND AGRESSIVE PLANT SPECIES IN COASTAL WETLANDS OF THE LAURENTIAN GREAT LAKES: A COMBINED FIELD BASED AND REMOTE SENSING APPROACH

EPA Science Inventory

The aquatic plant communities within coastal wetlands of the Laurentian Great Lakes are among the most biologically diverse and productive systems of the world. Coastal wetlands have been especially impacted by landscape conversion and have undergone a marked decline in plant com...

Tapping soil survey information for rapid assessment of sagebrush ecosystem resilience and resistance

Treesearch

Jeremy D. Maestas; Steven B. Campbell; Jeanne C. Chambers; Mike Pellant; Richard F. Miller

2016-01-01

A new ecologically-based approach to risk abatement has emerged that can aid land managers in grappling with escalating impacts of large-scale wildfire and invasive annual grasses in sagebrush ecosystems, particularly in the Great Basin. Specifically, ecosystem resilience and resistance (R&R) concepts have been more fully operationalized from regional...

Impacts of invasive fish removal through angling on population characteristics and juvenile growth rate.

PubMed

Evangelista, Charlotte; Britton, Robert J; Cucherousset, Julien

2015-06-01

Exploitation can modify the characteristics of fish populations through the selective harvesting of individuals, with this potentially leading to rapid ecological and evolutionary changes. Despite the well-known effects of invasive fishes on aquatic ecosystems generally, the potential effects of their selective removal through angling, a strategy commonly used to manage invasive fish, are poorly understood. The aim of this field-based study was to use the North American pumpkinseed Lepomis gibbosus as the model species to investigate the consequences of selective removal on their population characteristics and juvenile growth rates across 10 populations in artificial lakes in southern France. We found that the maximal individual mass in populations decreased as removal pressure through angling increased, whereas we did not observed any changes in the maximal individual length in populations as removal pressure increased. Total population abundance did not decrease as removal pressure increased; instead, here was a U-shaped relationship between removal pressure and the abundance of medium-bodied individuals. In addition, population biomass had a U-shaped curve response to removal pressure, implying that invasive fish populations can modulate their characteristics to compensate for the negative effects of selective removals. In addition, individual lengths at age 2 and juvenile growth rates decreased as removal pressure through angling increased, suggesting a shift toward an earlier size at maturity and an overall slower growing phenotype. Therefore, these outputs challenge the efficiency of selective management methods, suggesting the use of more proactive strategies to control invasive populations, and the need to investigate the potential ecological and evolutionary repercussions of nonrandom removal.

Impacts of invasive fish removal through angling on population characteristics and juvenile growth rate

PubMed Central

Evangelista, Charlotte; Britton, Robert J; Cucherousset, Julien

2015-01-01

Exploitation can modify the characteristics of fish populations through the selective harvesting of individuals, with this potentially leading to rapid ecological and evolutionary changes. Despite the well-known effects of invasive fishes on aquatic ecosystems generally, the potential effects of their selective removal through angling, a strategy commonly used to manage invasive fish, are poorly understood. The aim of this field-based study was to use the North American pumpkinseed Lepomis gibbosus as the model species to investigate the consequences of selective removal on their population characteristics and juvenile growth rates across 10 populations in artificial lakes in southern France. We found that the maximal individual mass in populations decreased as removal pressure through angling increased, whereas we did not observed any changes in the maximal individual length in populations as removal pressure increased. Total population abundance did not decrease as removal pressure increased; instead, here was a U-shaped relationship between removal pressure and the abundance of medium-bodied individuals. In addition, population biomass had a U-shaped curve response to removal pressure, implying that invasive fish populations can modulate their characteristics to compensate for the negative effects of selective removals. In addition, individual lengths at age 2 and juvenile growth rates decreased as removal pressure through angling increased, suggesting a shift toward an earlier size at maturity and an overall slower growing phenotype. Therefore, these outputs challenge the efficiency of selective management methods, suggesting the use of more proactive strategies to control invasive populations, and the need to investigate the potential ecological and evolutionary repercussions of nonrandom removal. PMID:26078856

Plant origin and ploidy influence gene expression and life cycle characteristics in an invasive weed.

PubMed

Broz, Amanda K; Manter, Daniel K; Bowman, Gillianne; Müller-Schärer, Heinz; Vivanco, Jorge M

2009-03-23

Ecological, evolutionary and physiological studies have thus far provided an incomplete picture of why some plants become invasive; therefore we used genomic resources to complement and advance this field. In order to gain insight into the invasive mechanism of Centaurea stoebe we compared plants of three geo-cytotypes, native Eurasian diploids, native Eurasian tetraploids and introduced North American tetraploids, grown in a common greenhouse environment. We monitored plant performance characteristics and life cycle habits and characterized the expression of genes related to constitutive defense and genome stability using quantitative PCR. Plant origin and ploidy were found to have a significant effect on both life cycle characteristics and gene expression, highlighting the importance of comparing appropriate taxonomic groups in studies of native and introduced plant species. We found that introduced populations of C. stoebe exhibit reduced expression of transcripts related to constitutive defense relative to their native tetraploid counterparts, as might be expected based on ideas of enemy release and rapid evolution. Measurements of several vegetative traits were similar for all geo-cytotypes; however, fecundity of tetraploids was significantly greater than diploids, due in part to their polycarpic nature. A simulation of seed production over time predicts that introduced tetraploids have the highest fecundity of the three geo-cytotypes. Our results suggest that characterizing gene expression in an invasive species using populations from both its native and introduced range can provide insight into the biology of plant invasion that can complement traditional measurements of plant performance. In addition, these results highlight the importance of using appropriate taxonomic units in ecological genomics investigations.

Insight on invasions and resilience derived from spatiotemporal discontinuities of biomass at local and regional scales

USGS Publications Warehouse

Angeler, David G.; Allen, Criag R.; Johnson, Richard K.

2012-01-01

Understanding the social and ecological consequences of species invasions is complicated by nonlinearities in processes, and differences in process and structure as scale is changed. Here we use discontinuity analyses to investigate nonlinear patterns in the distribution of biomass of an invasive nuisance species that could indicate scale-specific organization. We analyze biomass patterns in the flagellate Gonyostomum semen (Raphidophyta) in 75 boreal lakes during an 11-year period (1997-2007). With simulations using a unimodal null model and cluster analysis, we identified regional groupings of lakes based on their biomass patterns. We evaluated the variability of membership of individual lakes in regional biomass groups. Temporal trends in local and regional discontinuity patterns were analyzed using regressions and correlations with environmental variables that characterize nutrient conditions, acidity status, temperature variability, and water clarity. Regionally, there was a significant increase in the number of biomass groups over time, indicative of an increased number of scales at which algal biomass organizes across lakes. This increased complexity correlated with the invasion history of G. semen and broad-scale environmental change (recovery from acidification). Locally, no consistent patterns of lake membership to regional biomass groups were observed, and correlations with environmental variables were lake specific. The increased complexity of regional biomass patterns suggests that processes that act within or between scales reinforce the presence of G. semen and its potential to develop high-biomass blooms in boreal lakes. Emergent regional patterns combined with locally stochastic dynamics suggest a bleak future for managing G. semen, and more generally why invasive species can be ecologically successful.

A functional trait perspective on plant invasion

PubMed Central

Drenovsky, Rebecca E.; Grewell, Brenda J.; D'Antonio, Carla M.; Funk, Jennifer L.; James, Jeremy J.; Molinari, Nicole; Parker, Ingrid M.; Richards, Christina L.

2012-01-01

Background and Aims Global environmental change will affect non-native plant invasions, with profound potential impacts on native plant populations, communities and ecosystems. In this context, we review plant functional traits, particularly those that drive invader abundance (invasiveness) and impacts, as well as the integration of these traits across multiple ecological scales, and as a basis for restoration and management. Scope We review the concepts and terminology surrounding functional traits and how functional traits influence processes at the individual level. We explore how phenotypic plasticity may lead to rapid evolution of novel traits facilitating invasiveness in changing environments and then ‘scale up’ to evaluate the relative importance of demographic traits and their links to invasion rates. We then suggest a functional trait framework for assessing per capita effects and, ultimately, impacts of invasive plants on plant communities and ecosystems. Lastly, we focus on the role of functional trait-based approaches in invasive species management and restoration in the context of rapid, global environmental change. Conclusions To understand how the abundance and impacts of invasive plants will respond to rapid environmental changes it is essential to link trait-based responses of invaders to changes in community and ecosystem properties. To do so requires a comprehensive effort that considers dynamic environmental controls and a targeted approach to understand key functional traits driving both invader abundance and impacts. If we are to predict future invasions, manage those at hand and use restoration technology to mitigate invasive species impacts, future research must focus on functional traits that promote invasiveness and invader impacts under changing conditions, and integrate major factors driving invasions from individual to ecosystem levels. PMID:22589328

The behavior of multiple independent managers and ecological traits interact to determine prevalence of weeds.

PubMed

Coutts, Shaun R; Yokomizo, Hiroyuki; Buckley, Yvonne M

2013-04-01

Management of damaging invasive plants is often undertaken by multiple decision makers, each managing only a small part of the invader's population. As weeds can move between properties and re-infest eradicated sites from unmanaged sources, the dynamics of multiple decision makers plays a significant role in weed prevalence and invasion risk at the landscape scale. We used a spatially explicit agent-based simulation to determine how individual agent behavior, in concert with weed population ecology, determined weed prevalence. We compared two invasive grass species that differ in ecology, control methods, and costs: Nassella trichotoma (serrated tussock) and Eragrostis curvula (African love grass). The way decision makers reacted to the benefit of management had a large effect on the extent of a weed. If benefits of weed control outweighed the costs, and either net benefit was very large or all agents were very sensitive to net benefits, then agents tended to act synchronously, reducing the pool of infested agents available to spread the weed. As N. trichotoma was more damaging than E. curvula and had more effective control methods, agents chose to manage it more often, which resulted in lower prevalence of N. trichotoma. A relatively low number of agents who were intrinsically less motivated to control weeds led to increased prevalence of both species. This was particularly apparent when long-distance dispersal meant each infested agent increased the invasion risk for a large portion of the landscape. In this case, a small proportion of land mangers reluctant to control, regardless of costs and benefits, could lead to the whole landscape being infested, even when local control stopped new infestations. Social pressure was important, but only if it was independent of weed prevalence, suggesting that early access to information, and incentives to act on that information, may be crucial in stopping a weed from infesting large areas. The response of our model to both behavioral and ecological parameters was highly nonlinear. This implies that the outcomes of weed management programs that deal with multiple land mangers could be highly variable in both space and through time.

Improved understanding of weed biological control safety and impact with chemical ecology: a review

USDA-ARS?s Scientific Manuscript database

We review chemical ecology literature as it relates to weed biological control and discuss how this means of controlling invasive plants could be enhanced by the consideration of several well established research developments. The interface between chemical ecology and weed biological control presen...

An invasive plant alters pollinator-mediated phenotypic selection on a native congener.

PubMed

Beans, Carolyn M; Roach, Deborah A

2015-01-01

• Recent studies suggest that invasive plants compete reproductively with native plants by reducing the quantity or quality of pollinator visits. Although these studies have revealed ecological consequences of pollinator-mediated competition between invasive and native plants, the evolutionary outcomes of these interactions remain largely unexplored.• We studied the ecological and evolutionary impact of pollinator-mediated competition with an invasive jewelweed, Impatiens glandulifera, on a co-occurring native congener, I. capensis. Using a pollinator choice experiment, a hand pollination experiment, and a selection analysis, we addressed the following questions: (1) Do native pollinators show preference for the invasive or native jewelweed, and do they move between the two species? (2) Does invasive jewelweed pollen inhibit seed production in the native plant? (3) Does the invasive jewelweed alter phenotypic selection on the native plant's floral traits?• The pollinator choice experiment showed that pollinators strongly preferred the invasive jewelweed. The hand pollination experiment demonstrated that invasive pollen inhibited seed production in the native plant. The selection analysis showed that the presence of the invasive jewelweed altered phenotypic selection on corolla height in the native plant.• Invasive plants have the potential to alter phenotypic selection on floral traits in native plant populations. If native plants can evolve in response to this altered selection pressure, the evolution of floral traits may play an important role in permitting long-term coexistence of native and invasive plants. © 2015 Botanical Society of America, Inc.

Knowledge gain and behavioral change in citizen-science programs.

PubMed

Jordan, Rebecca C; Gray, Steven A; Howe, David V; Brooks, Wesley R; Ehrenfeld, Joan G

2011-12-01

Citizen-science programs are often touted as useful for advancing conservation literacy, scientific knowledge, and increasing scientific-reasoning skills among the public. Guidelines for collaboration among scientists and the public are lacking and the extent to which these citizen-science initiatives change behavior is relatively unstudied. Over two years, we studied 82 participants in a three-day program that included education about non-native invasive plants and collection of data on the occurrence of those plants. Volunteers were given background knowledge about invasive plant ecology and trained on a specific protocol for collecting invasive plant data. They then collected data and later gathered as a group to analyze data and discuss responsible environmental behavior with respect to invasive plants. We tested whether participants without experience in plant identification and with little knowledge of invasive plants increased their knowledge of invasive species ecology, participation increased knowledge of scientific methods, and participation affected behavior. Knowledge of invasive plants increased on average 24%, but participation was insufficient to increase understanding of how scientific research is conducted. Participants reported increased ability to recognize invasive plants and increased awareness of effects of invasive plants on the environment, but this translated into little change in behavior regarding invasive plants. Potential conflicts between scientific goals, educational goals, and the motivation of participants must be considered during program design. ©2011 Society for Conservation Biology.

Proceedings, U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2002

Treesearch

Sandra L. C. Fosbroke; Kurt W. Gottschalk; [Editors

2003-01-01

Contains 75 abstracts and papers of oral and poster presentations on gypsy moth and other invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Research Forum on Gypsy Moth and Other Invasive Species.

Proceedings, 18th U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2007

Treesearch

Kurt W., ed. Gottschalk

2008-01-01

Contains 60 abstracts and papers of oral and poster presentations on gypsy moth and other invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species.

Proceedings, U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2003

Treesearch

Kurt W., ed. Gottschalk

2004-01-01

Contains 56 abstracts and papers of oral and poster presentations on gypsy moth and other invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Research Forum on Gypsy Moth and Other Invasive Species.

Proceedings, U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2001

Treesearch

Sandra L.C. Fosbroke; Kurt W., Gottschalk

2001-01-01

Contains 68 abstracts and papers of oral and poster presentations on gypsy moth and other invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture interagency research forum of gypsy moth and other invasive species.

Proceedings, 16th U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2005

Treesearch

Kurt W. Gottschalk

2005-01-01

Contains 61 abstracts and papers of oral and poster presentations on gypsy moth and other invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U. S. Department of Agriculture Interagency Research Forum on Gypsy Moth and Other Invasive Species.

Identifying Invasive Species Educational Needs in Florida: Opportunities for Extension

ERIC Educational Resources Information Center

Huang, Pei-wen; Lamm, Alexa J.

2016-01-01

Florida's ecology has been adversely affected by invasive species. In Florida, a study was conducted to explore opportunities for Extension educators to contribute to combating the issue of invasive species. Florida residents' responses were captured through the use of an online public opinion survey. The findings revealed a need for invasive…

Race to Displace: A Game to Model the Effects of Invasive Species on Plant Communities

ERIC Educational Resources Information Center

Hopwood, Jennifer L.; Flowers, Susan K.; Seidler, Katie J.; Hopwood, Erica L.

2013-01-01

Invasive species are a substantial threat to biodiversity. Educating students about invasive species introduces fundamental concepts in biology, ecology, and environmental science. In the Race to Displace game, students assume the characteristics of select native or introduced plants and experience first hand the influences of species interactions…

Micro-managing arthropod invasions: eradication and control of invasive arthropods with microbes

Treesearch

Ann E. Hajek; Patrick C. Tobin

2010-01-01

Non-indigenous arthropods are increasingly being introduced into new areas worldwide and occasionally they cause considerable ecological and economic harm. Many invasive arthropods particularly pose problems to areas of human habitation and native ecosystems. In these cases, the use of environmentally benign materials, such as host-specific entomopathogens, can be more...

Molecular genetics and genomics generate new insights into invertebrate pest invasions.

PubMed

Kirk, Heather; Dorn, Silvia; Mazzi, Dominique

2013-07-01

Invertebrate pest invasions and outbreaks are associated with high social, economic, and ecological costs, and their significance will intensify with an increasing pressure on agricultural productivity as a result of human population growth and climate change. New molecular genetic and genomic techniques are available and accessible, but have been grossly underutilized in studies of invertebrate pest invasions, despite that they are useful tools for applied pest management and for understanding fundamental features of pest invasions including pest population demographics and adaptation of pests to novel and/or changing environments. Here, we review current applications of molecular genetics and genomics in the study of invertebrate pest invasions and outbreaks, and we highlight shortcomings from the current body of research. We then discuss recent conceptual and methodological advances in the areas of molecular genetics/genomics and data analysis, and we highlight how these advances will further our understanding of the demographic, ecological, and evolutionary features of invertebrate pest invasions. We are now well equipped to use molecular data to understand invertebrate dispersal and adaptation, and this knowledge has valuable applications in agriculture at a time when these are critically required.

Impact of the Invasive Brown Marmorated Stink Bug in North America and Europe: History, Biology, Ecology, and Management.

PubMed

Leskey, Tracy C; Nielsen, Anne L

2018-01-07

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), is an invasive pentatomid introduced from Asia into the United States, Canada, multiple European countries, and Chile. In 2010, BMSB populations in the mid-Atlantic United States reached outbreak levels and subsequent feeding severely damaged tree fruit as well as other crops. Significant nuisance issues from adults overwintering inside homes were common. BMSB is a highly polyphagous species with a strong dispersal capacity and high reproductive output, potentially enabling its spread and success in invaded regions. A greater understanding of BMSB biology and ecology and its natural enemies, the identification of the male-produced aggregation pheromone, and the recognition that BMSB disperses into crops from adjacent wooded habitats have led to the development of behavior-based integrated pest management (IPM) tactics. Much is still unknown about BMSB, and continued long-term collaborative studies are necessary to refine crop-specific IPM programs and enhance biological control across invaded landscapes.

Transatlantic invasion routes and adaptive potential in North American populations of the invasive glossy buckthorn, Frangula alnus

PubMed Central

De Kort, Hanne; Mergeay, Joachim; Jacquemyn, Hans; Honnay, Olivier

2016-01-01

Background and Aims Many invasive species severely threaten native biodiversity and ecosystem functioning. One of the most prominent questions in invasion genetics is how invasive populations can overcome genetic founder effects to establish stable populations after colonization of new habitats. High native genetic diversity and multiple introductions are expected to increase genetic diversity and adaptive potential in the invasive range. Our aim was to identify the European source populations of Frangula alnus (glossy buckthorn), an ornamental and highly invasive woody species that was deliberately introduced into North America at the end of the 18th century. A second aim of this study was to assess the adaptive potential as an explanation for the invasion success of this species. Methods Using a set of annotated single-nucleotide polymorphisms (SNPs) that were assigned a putative function based on sequence comparison with model species, a total of 38 native European and 21 invasive North American populations were subjected to distance-based structure and assignment analyses combined with population genomic tools. Genetic diversity at SNPs with ecologically relevant functions was considered as a proxy for adaptive potential. Key Results Patterns of invasion coincided with early modern transatlantic trading routes. Multiple introductions through transatlantic trade from a limited number of European port regions to American urban areas led to the establishment of bridgehead populations with high allelic richness and expected heterozygosity, allowing continuous secondary migration to natural areas. Conclusions Targeted eradication of the urban populations, where the highest genetic diversity and adaptive potential were observed, offers a promising strategy to arrest further invasion of native American prairies and forests. PMID:27539599

Ecological theory as a foundation to control pathogenic invasion in aquaculture

PubMed Central

De Schryver, Peter; Vadstein, Olav

2014-01-01

Detrimental host–pathogen interactions are a normal phenomenon in aquaculture animal production, and have been counteracted by prophylactic use of antibiotics. Especially, the youngest life stages of cultivated aquatic animals are susceptible to pathogen invasion, resulting in disease and mortality. To establish a more sustainable aquatic food production, there is a need for new microbial management strategies that focus on ‘join them' and not the traditional ‘beat them' approaches. We argue that ecological theory could serve as a foundation for developing sustainable microbial management methods that prevent pathogenic disease in larviculture. Management of the water microbiota in aquaculture systems according to ecological selection principles has been shown to decrease opportunistic pathogen pressure and to result in an improved performance of the cultured animals. We hypothesize that manipulation of the biodiversity of the gut microbiota can increase the host's resistance against pathogenic invasion and infection. However, substantial barriers need to be overcome before active management of the intestinal microbiota can effectively be applied in larviculture. PMID:24892581

Effects of Praxelis clematidea invasion on soil nitrogen fractions and transformation rates in a tropical savanna.

PubMed

Wei, Hui; Xu, Jialin; Quan, Guoming; Zhang, Jiaen; Qin, Zhong

2017-02-01

Plant invasion has been reported to affect a mass of soil ecological processes and functions, although invasion effects are often context-, species- and ecosystem- specific. This study was conducted to explore potential impacts of Praxelis clematidea invasion on contents of total and available soil nitrogen (N) and microbial N transformations in a tropical savanna. Soil samples were collected from the surface and sub-surface layers in plots with non-, slight, or severe P. clematidea invasion in Hainan Province of southern China, which remains less studied, and analyzed for contents of the total and available N fractions and microbial N transformations. Results showed that total N content significantly increased in the surface soil but trended to decrease in the sub-surface soil in the invaded plots relative to the non-invaded control. Slight invasion significantly increased soil alkali-hydrolysable N content in the two soil layers. Soil net N mineralization rate was not significantly changed in both the soil layers, although soil microbial biomass N was significantly higher in plots with severe invasion than the control. There was no significant difference in content of soil N fractions between plots with slight and severe invasion. Our results suggest that invasion of P. clematidea promotes soil N accumulation in the surface soil layer, which is associated with increased microbial biomass N. However, the invasion-induced ecological impacts did not increase with further invasion. Significantly higher microbial biomass N was maintained in plots with severe invasion, implying that severe P. clematidea invasion may accelerate nutrient cycling in invaded ecosystems.

Progress in understanding the ecology and detection of Sirex noctilio

Treesearch

Matthew P. Ayres; Jenna M. Sullivan; Tina Harrison; Kelley E. Zylstra; Kevin J. Dodds; Jeffrey R. Garnas; Victor C. Mastro; Maria J. Lombardero

2011-01-01

We have been developing techniques for detecting the presence of Sirex noctilio and studying the ecology of Sirex noctilio in North America with the goal of anticipating the trajectory of the Sirex invasion.

Asymmetric effects of native and exotic invasive shrubs on ecology of the West Nile virus vector Culex pipiens (Diptera: Culicidae).

PubMed

Gardner, Allison M; Allan, Brian F; Frisbie, Lauren A; Muturi, Ephantus J

2015-06-16

Exotic invasive plants alter the structure and function of native ecosystems and may influence the distribution and abundance of arthropod disease vectors by modifying habitat quality. This study investigated how invasive plants alter the ecology of Culex pipiens, an important vector of West Nile virus (WNV) in northeastern and midwestern regions of the United States. Field and laboratory experiments were conducted to test the hypothesis that three native leaf species (Rubus allegheniensis, blackberry; Sambucus canadensis, elderberry; and Amelanchier laevis, serviceberry), and three exotic invasive leaf species (Lonicera maackii, Amur honeysuckle; Elaeagnus umbellata, autumn olive; and Rosa multiflora, multiflora rose) alter Cx. pipiens oviposition site selection, emergence rates, development time, and adult body size. The relative abundance of seven bacterial phyla in infusions of the six leaf species also was determined using quantitative real-time polymerase chain reaction to test the hypothesis that variation in emergence, development, and oviposition site selection is correlated to differences in the diversity and abundance of bacteria associated with different leaf species, important determinants of nutrient quality and availability for mosquito larvae. Leaf detritus from invasive honeysuckle and autumn olive yielded significantly higher adult emergence rates compared to detritus from the remaining leaf species and honeysuckle alleviated the negative effects of intraspecific competition on adult emergence. Conversely, leaves of native blackberry acted as an ecological trap, generating high oviposition but low emergence rates. Variation in bacterial flora associated with different leaf species may explain this asymmetrical production of mosquitoes: emergence rates and oviposition rates were positively correlated to bacterial abundance and diversity, respectively. We conclude that the displacement of native understory plant species by certain invasive shrubs may increase production of Cx. pipiens with potential negative repercussions for human and wildlife health. These findings may be relevant to mosquito control and invasive plant management practices in the geographic range of Cx. pipiens. Further, our discovery of a previously unknown ecological trap for an important vector of WNV has the potential to lead to novel alternatives to conventional insecticides in mosquito control by exploiting the apparent "attract-kill" properties of this native plant species.

Invasive forest pathogens: Summary of issues, critical needs, and future goals for Forest Service Research and Development

Treesearch

Ned B. Klopfenstein; Jennifer Juzwik; Michael E. Ostry; Mee-Sook Kim; Paul J. Zambino; Robert C. Venette; Bryce A. Richardson; John E. Lundquist; D. Jean Lodge; Jessie A. Glaeser; Susan J. Frankel; William J. Otrosina; Pauline Spaine; Brian W. Geils

2010-01-01

Invasive pathogens have caused immeasurable ecological and economic damage to forest ecosystems. Damage will undoubtedly increase over time due to increased introductions and evolution of invasive pathogens in concert with complex environmental disturbances, such as climate change. Forest Service Research and Development must fulfill critical roles and responsibilities...

The Politics of Invasive Weed Management: Gender, Race, and Risk Perception in Rural California

ERIC Educational Resources Information Center

Norgaard, Kari Marie

2007-01-01

"Biological invasions" are now recognized as the cause of significant ecological and economic damage. They also raise a series of less visible social issues. Management of invasive species is often a political process raising questions such as who decides which organisms are to be managed, and who benefits or is affected by different…

Applying ecological concepts to the management of widespread grass invasions [Chapter 7

Treesearch

Carla M. D' Antonio; Jeanne C. Chambers; Rhonda Loh; J. Tim Tunison

2009-01-01

The management of plant invasions has typically focused on the removal of invading populations or control of existing widespread species to unspecified but lower levels. Invasive plant management typically has not involved active restoration of background vegetation to reduce the likelihood of invader reestablishment. Here, we argue that land managers could benefit...

Spatial scaling of non-native fish richness across the United States

Treesearch

Qinfeng Guo; Julian D. Olden

2014-01-01

A major goal and challenge of invasion ecology is to describe and interpret spatial and temporal patterns of species invasions. Here, we examined fish invasion patterns at four spatially structured and hierarchically nested scales across the contiguous United States (i.e., from large to small: region, basin, watershed, and sub-watershed). All spatial relationships in...

Ecological correlates of invasion impact for Burmese pythons in Florida.

PubMed

Reed, Robert N; Willson, John D; Rodda, Gordon H; Dorcas, Michael E

2012-09-01

An invasive population of Burmese pythons (Python molurus bivittatus) is established across several thousand square kilometers of southern Florida and appears to have caused precipitous population declines among several species of native mammals. Why has this giant snake had such great success as an invasive species when many established reptiles have failed to spread? We scored the Burmese python for each of 15 literature-based attributes relative to predefined comparison groups from a diverse range of taxa and provide a review of the natural history and ecology of Burmese pythons relevant to each attribute. We focused on attributes linked to spread and magnitude of impacts rather than establishment success. Our results suggest that attributes related to body size and generalism appeared to be particularly applicable to the Burmese python's success in Florida. The attributes with the highest scores were: high reproductive potential, low vulnerability to predation, large adult body size, large offspring size and high dietary breadth. However, attributes of ectotherms in general and pythons in particular (including predatory mode, energetic efficiency and social interactions) might have also contributed to invasion success. Although establishment risk assessments are an important initial step in prevention of new establishments, evaluating species in terms of their potential for spreading widely and negatively impacting ecosystems might become part of the means by which resource managers prioritize control efforts in environments with large numbers of introduced species. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

Land management in the Anthropocene: is history still relevant?: Incorporating historical ecology and climate change into land management; Lansdowne, Virginia, 22–25 April 2008

USGS Publications Warehouse

Safford, Hugh D.; Betancourt, Julio L.; Hayward, Gregory D.; Wiens, John A.; Regan, Claudia M.

2008-01-01

Ecological restoration, conservation, and land management are often based on comparisons with reference sites or time periods, which are assumed to represent “natural” or “properly functioning” conditions. Such reference conditions can provide a vision of the conservation or management goal and a means to measure progress toward that vision. Although historical ecology has been used successfully to guide resource management in many parts of the world, the continuing relevance of history is now being questioned. Some scientists doubt that lessons from the past can inform management in what may be a dramatically different future, given profound climate change, accelerated land use, and an onslaught of plant and animal invasions.

Validation of a Mechanistic Model for Non-Invasive Study of Ecological Energetics in an Endangered Wading Bird with Counter-Current Heat Exchange in its Legs.

PubMed

Fitzpatrick, Megan J; Mathewson, Paul D; Porter, Warren P

2015-01-01

Mechanistic models provide a powerful, minimally invasive tool for gaining a deeper understanding of the ecology of animals across geographic space and time. In this paper, we modified and validated the accuracy of the mechanistic model Niche Mapper for simulating heat exchanges of animals with counter-current heat exchange mechanisms in their legs and animals that wade in water. We then used Niche Mapper to explore the effects of wading and counter-current heat exchange on the energy expenditures of Whooping Cranes, a long-legged wading bird. We validated model accuracy against the energy expenditure of two captive Whooping Cranes measured using the doubly-labeled water method and time energy budgets. Energy expenditure values modeled by Niche Mapper were similar to values measured by the doubly-labeled water method and values estimated from time-energy budgets. Future studies will be able to use Niche Mapper as a non-invasive tool to explore energy-based limits to the fundamental niche of Whooping Cranes and apply this knowledge to management decisions. Basic questions about the importance of counter-current exchange and wading to animal physiological tolerances can also now be explored with the model.

Validation of a Mechanistic Model for Non-Invasive Study of Ecological Energetics in an Endangered Wading Bird with Counter-Current Heat Exchange in its Legs

PubMed Central

Fitzpatrick, Megan J.; Mathewson, Paul D.; Porter, Warren P.

2015-01-01

Mechanistic models provide a powerful, minimally invasive tool for gaining a deeper understanding of the ecology of animals across geographic space and time. In this paper, we modified and validated the accuracy of the mechanistic model Niche Mapper for simulating heat exchanges of animals with counter-current heat exchange mechanisms in their legs and animals that wade in water. We then used Niche Mapper to explore the effects of wading and counter-current heat exchange on the energy expenditures of Whooping Cranes, a long-legged wading bird. We validated model accuracy against the energy expenditure of two captive Whooping Cranes measured using the doubly-labeled water method and time energy budgets. Energy expenditure values modeled by Niche Mapper were similar to values measured by the doubly-labeled water method and values estimated from time-energy budgets. Future studies will be able to use Niche Mapper as a non-invasive tool to explore energy-based limits to the fundamental niche of Whooping Cranes and apply this knowledge to management decisions. Basic questions about the importance of counter-current exchange and wading to animal physiological tolerances can also now be explored with the model. PMID:26308207

Meta-analysis reveals evolution in invasive plant species but little support for Evolution of Increased Competitive Ability (EICA).

PubMed

Felker-Quinn, Emmi; Schweitzer, Jennifer A; Bailey, Joseph K

2013-03-01

Ecological explanations for the success and persistence of invasive species vastly outnumber evolutionary hypotheses, yet evolution is a fundamental process in the success of any species. The Evolution of Increased Competitive Ability (EICA) hypothesis (Blossey and Nötzold 1995) proposes that evolutionary change in response to release from coevolved herbivores is responsible for the success of many invasive plant species. Studies that evaluate this hypothesis have used different approaches to test whether invasive populations allocate fewer resources to defense and more to growth and competitive ability than do source populations, with mixed results. We conducted a meta-analysis of experimental tests of evolutionary change in the context of EICA. In contrast to previous reviews, there was no support across invasive species for EICA's predictions regarding defense or competitive ability, although invasive populations were more productive than conspecific native populations under noncompetitive conditions. We found broad support for genetically based changes in defense and competitive plant traits after introduction into new ranges, but not in the manner suggested by EICA. This review suggests that evolution occurs as a result of plant introduction and population expansion in invasive plant species, and may contribute to the invasiveness and persistence of some introduced species.

Meta-analysis reveals evolution in invasive plant species but little support for Evolution of Increased Competitive Ability (EICA)

PubMed Central

Felker-Quinn, Emmi; Schweitzer, Jennifer A; Bailey, Joseph K

2013-01-01

Ecological explanations for the success and persistence of invasive species vastly outnumber evolutionary hypotheses, yet evolution is a fundamental process in the success of any species. The Evolution of Increased Competitive Ability (EICA) hypothesis (Blossey and Nötzold 1995) proposes that evolutionary change in response to release from coevolved herbivores is responsible for the success of many invasive plant species. Studies that evaluate this hypothesis have used different approaches to test whether invasive populations allocate fewer resources to defense and more to growth and competitive ability than do source populations, with mixed results. We conducted a meta-analysis of experimental tests of evolutionary change in the context of EICA. In contrast to previous reviews, there was no support across invasive species for EICA's predictions regarding defense or competitive ability, although invasive populations were more productive than conspecific native populations under noncompetitive conditions. We found broad support for genetically based changes in defense and competitive plant traits after introduction into new ranges, but not in the manner suggested by EICA. This review suggests that evolution occurs as a result of plant introduction and population expansion in invasive plant species, and may contribute to the invasiveness and persistence of some introduced species. PMID:23531703

Unveiling an ancient biological invasion: molecular analysis of an old European alien, the crested porcupine (Hystrix cristata).

PubMed

Trucchi, Emiliano; Sbordoni, Valerio

2009-05-18

Biological invasions can be considered one of the main threats to biodiversity, and the recognition of common ecological and evolutionary features among invaders can help developing a predictive framework to control further invasions. In particular, the analysis of successful invasive species and of their autochthonous source populations by means of genetic, phylogeographic and demographic tools can provide novel insights into the study of biological invasion patterns. Today, long-term dynamics of biological invasions are still poorly understood and need further investigations. Moreover, distribution and molecular data on native populations could contribute to the recognition of common evolutionary features of successful aliens. We analyzed 2,195 mitochondrial base pairs, including Cytochrome b, Control Region and rRNA 12S, in 161 Italian and 27 African specimens and assessed the ancient invasive origin of Italian crested porcupine (Hystrix cristata) populations from Tunisia. Molecular coalescent-based Bayesian analyses proposed the Roman Age as a putative timeframe of introduction and suggested a retention of genetic diversity during the early phases of colonization. The characterization of the native African genetic background revealed the existence of two differentiated clades: a Mediterranean group and a Sub-Saharan one. Both standard population genetic and advanced molecular demography tools (Bayesian Skyline Plot) did not evidence a clear genetic signature of the expected increase in population size after introduction. Along with the genetic diversity retention during the bottlenecked steps of introduction, this finding could be better described by hypothesizing a multi-invasion event. Evidences of the ancient anthropogenic invasive origin of the Italian Hystrix cristata populations were clearly shown and the native African genetic background was preliminary described. A more complex pattern than a simple demographic exponential growth from a single propagule seems to have characterized this long-term invasion.

Innovative design for early detection of invasive species

EPA Science Inventory

Non-native aquatic species impose significant ecological impacts and rising financial costs in marine and freshwater ecosystems worldwide. Early detection of invasive species, as they enter a vulnerable ecosystem, is critical to successful containment and eradication. ORD, at t...

Invasive plant management on anticipated conservation benefits: a scientific Assessment

USDA-ARS?s Scientific Manuscript database

Invasive plants negatively impact rangelands throughout the western United States by displacing desirable species, altering ecological processes, reducing wildlife habitat, degrading systems, altering fire regimes, and decreasing productivity. Assessing the influence of conservation practices on var...

Will extreme climatic events facilitate biological invasions?

USDA-ARS?s Scientific Manuscript database

Extreme climatic events, such as intense heat waves, hurricanes, floods and droughts, can dramatically affect ecological and evolutionary processes, and more extreme events are projected with ongoing climate change. However, the implications of these events for biological invasions, which themselves...

Fortune favours the bold: a higher predator reduces the impact of a native but not an invasive intermediate predator.

PubMed

Barrios-O'Neill, Daniel; Dick, Jaimie T A; Emmerson, Mark C; Ricciardi, Anthony; MacIsaac, Hugh J; Alexander, Mhairi E; Bovy, Helene C

2014-05-01

Emergent multiple predator effects (MPEs) might radically alter predictions of predatory impact that are based solely on the impact of individuals. In the context of biological invasions, determining if and how the individual-level impacts of invasive predators relates to their impacts in multiple-individual situations will inform understanding of how such impacts might propagate through recipient communities. Here, we use functional responses (the relationship between prey consumption rate and prey density) to compare the impacts of the invasive freshwater mysid crustacean Hemimysis anomala with a native counterpart Mysis salemaai when feeding on basal cladoceran prey (i) as individuals, (ii) in conspecific groups and (iii) in conspecific groups in the presence of a higher fish predator, Gasterosteus aculeatus. In the absence of the higher predator, the invader consumed significantly more basal prey than the native, and consumption was additive for both mysid species - that is, group consumption was predictable from individual-level consumption. Invaders and natives were themselves equally susceptible to predation when feeding with the higher fish predator, but an MPE occurred only between the natives and higher predator, where consumption of basal prey was significantly reduced. In contrast, consumption by the invaders and higher predator remained additive. The presence of a higher predator serves to exacerbate the existing difference in individual-level consumption between invasive and native mysids. We attribute the mechanism responsible for the MPE associated with the native to a trait-mediated indirect interaction, and further suggest that the relative indifference to predator threat on the part of the invader contributes to its success and impacts within invaded communities. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

Proceedings, 17th U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2006

Treesearch

Kurt W., ed. Gottschalk

2007-01-01

Contains three abstracts and papers from the 2005 Forum and 70 abstracts and papers of oral and poster presentations on gypsy moth and other invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Research Forum on Gypsy Moth and Other Invasive Species.

The putative niche requirements and landscape dynamics of Microstegium vimineum: an invasive Asian grass

Treesearch

Robert J. II Warren; Justin P. Wright; Mark A. Bradford

2010-01-01

The theoretical foundations of population and community ecology stress the importance of identifying crucial niche requirements and life history stages of invasive species and, in doing so, give insight into research and management. We focus on Microstegium vimineum, an invasive grass which is causing marked changes in the structure and function of US forests. We...

Endophytic fungal communities of Bromus tectorum: Mutualisms, community assemblages and implications for invasion

Treesearch

Melissa A. Baynes

2011-01-01

Exotic plant invasions are of serious economic, social and ecological concern worldwide. Although many promising hypotheses have been posited in attempt to explain the mechanism(s) by which plant invaders are successful, there is no single explanation for all invasions and often no single explanation for the success of an individual species. Cheatgrass (Bromus tectorum...

Patterns and consequences of re-invasion into a Hawaiian dry forest restoration

Treesearch

Erin J. Questad; Jarrod M. Thaxton; Susan Cordell

2012-01-01

The restoration of native plant diversity may be an effective tool for weed control, but its use has not been tested in the heavily invaded Hawaiian dry forest ecosystem. In addition, the ecological mechanisms by which invasive plants may cause declines in native plant diversity are generally not well understood. We examined invasion resistance and the relationships...

Efficient distinction of invasive aquatic plant species from non-invasive related species using DNA barcoding.

PubMed

Ghahramanzadeh, R; Esselink, G; Kodde, L P; Duistermaat, H; van Valkenburg, J L C H; Marashi, S H; Smulders, M J M; van de Wiel, C C M

2013-01-01

Biological invasions are regarded as threats to global biodiversity. Among invasive aliens, a number of plant species belonging to the genera Myriophyllum, Ludwigia and Cabomba, and to the Hydrocharitaceae family pose a particular ecological threat to water bodies. Therefore, one would try to prevent them from entering a country. However, many related species are commercially traded, and distinguishing invasive from non-invasive species based on morphology alone is often difficult for plants in a vegetative stage. In this regard, DNA barcoding could become a good alternative. In this study, 242 samples belonging to 26 species from 10 genera of aquatic plants were assessed using the chloroplast loci trnH-psbA, matK and rbcL. Despite testing a large number of primer sets and several PCR protocols, the matK locus could not be amplified or sequenced reliably and therefore was left out of the analysis. Using the other two loci, eight invasive species could be distinguished from their respective related species, a ninth one failed to produce sequences of sufficient quality. Based on the criteria of universal application, high sequence divergence and level of species discrimination, the trnH-psbA noncoding spacer was the best performing barcode in the aquatic plant species studied. Thus, DNA barcoding may be helpful with enforcing a ban on trade of such invasive species, such as is already in place in the Netherlands. This will become even more so once DNA barcoding would be turned into machinery routinely operable by a nonspecialist in botany and molecular genetics. © 2012 Blackwell Publishing Ltd.

Enhancing the effectiveness of biological control programs of invasive species through a more comprehensive pest management approach.

PubMed

DiTomaso, Joseph M; Van Steenwyk, Robert A; Nowierski, Robert M; Vollmer, Jennifer L; Lane, Eric; Chilton, Earl; Burch, Patrick L; Cowan, Phil E; Zimmerman, Kenneth; Dionigi, Christopher P

2017-01-01

Invasive species are one of the greatest economic and ecological threats to agriculture and natural areas in the US and the world. Among the available management tools, biological control provides one of the most economical and long-term effective strategies for managing widespread and damaging invasive species populations of nearly all taxa. However, integrating biological control programs in a more complete integrated pest management approach that utilizes increased information and communication, post-release monitoring, adaptive management practices, long-term stewardship strategies, and new and innovative ecological and genetic technologies can greatly improve the effectiveness of biological control. In addition, expanding partnerships among relevant national, regional, and local agencies, as well as academic scientists and land managers, offers far greater opportunities for long-term success in the suppression of established invasive species. In this paper we direct our recommendations to federal agencies that oversee, fund, conduct research, and develop classical biological control programs for invasive species. By incorporating these recommendations into adaptive management strategies, private and public land managers will have far greater opportunities for long-term success in suppression of established invasive species. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

High invasion potential of Hydrilla verticillata in the Americas predicted using ecological niche modeling combined with genetic data.

PubMed

Zhu, Jinning; Xu, Xuan; Tao, Qing; Yi, Panpan; Yu, Dan; Xu, Xinwei

2017-07-01

Ecological niche modeling is an effective tool to characterize the spatial distribution of suitable areas for species, and it is especially useful for predicting the potential distribution of invasive species. The widespread submerged plant Hydrilla verticillata (hydrilla) has an obvious phylogeographical pattern: Four genetic lineages occupy distinct regions in native range, and only one lineage invades the Americas. Here, we aimed to evaluate climatic niche conservatism of hydrilla in North America at the intraspecific level and explore its invasion potential in the Americas by comparing climatic niches in a phylogenetic context. Niche shift was found in the invasion process of hydrilla in North America, which is probably mainly attributed to high levels of somatic mutation. Dramatic changes in range expansion in the Americas were predicted in the situation of all four genetic lineages invading the Americas or future climatic changes, especially in South America; this suggests that there is a high invasion potential of hydrilla in the Americas. Our findings provide useful information for the management of hydrilla in the Americas and give an example of exploring intraspecific climatic niche to better understand species invasion.

Hierarchical spatiotemporal matrix models for characterizing invasions

USGS Publications Warehouse

Hooten, M.B.; Wikle, C.K.; Dorazio, R.M.; Royle, J. Andrew

2007-01-01

The growth and dispersal of biotic organisms is an important subject in ecology. Ecologists are able to accurately describe survival and fecundity in plant and animal populations and have developed quantitative approaches to study the dynamics of dispersal and population size. Of particular interest are the dynamics of invasive species. Such nonindigenous animals and plants can levy significant impacts on native biotic communities. Effective models for relative abundance have been developed; however, a better understanding of the dynamics of actual population size (as opposed to relative abundance) in an invasion would be beneficial to all branches of ecology. In this article, we adopt a hierarchical Bayesian framework for modeling the invasion of such species while addressing the discrete nature of the data and uncertainty associated with the probability of detection. The nonlinear dynamics between discrete time points are intuitively modeled through an embedded deterministic population model with density-dependent growth and dispersal components. Additionally, we illustrate the importance of accommodating spatially varying dispersal rates. The method is applied to the specific case of the Eurasian Collared-Dove, an invasive species at mid-invasion in the United States at the time of this writing.

Hierarchical spatiotemporal matrix models for characterizing invasions

USGS Publications Warehouse

Hooten, M.B.; Wikle, C.K.; Dorazio, R.M.; Royle, J. Andrew

2007-01-01

The growth and dispersal of biotic organisms is an important subject in ecology. Ecologists are able to accurately describe survival and fecundity in plant and animal populations and have developed quantitative approaches to study the dynamics of dispersal and population size. Of particular interest are the dynamics of invasive species. Such nonindigenous animals and plants can levy significant impacts on native biotic communities. Effective models for relative abundance have been developed; however, a better understanding of the dynamics of actual population size (as opposed to relative abundance) in an invasion would be beneficial to all branches of ecology. In this article, we adopt a hierarchical Bayesian framework for modeling the invasion of such species while addressing the discrete nature of the data and uncertainty associated with the probability of detection. The nonlinear dynamics between discrete time points are intuitively modeled through an embedded deterministic population model with density-dependent growth and dispersal components. Additionally, we illustrate the importance of accommodating spatially varying dispersal rates. The method is applied to the specific case of the Eurasian Collared-Dove, an invasive species at mid-invasion in the United States at the time of this writing. ?? 2006, The International Biometric Society.

Using economic instruments to develop effective management of invasive species: insights from a bioeconomic model.

PubMed

McDermott, Shana M; Irwin, Rebecca E; Taylor, Brad W

2013-07-01

Economic growth is recognized as an important factor associated with species invasions. Consequently, there is increasing need to develop solutions that combine economics and ecology to inform invasive species management. We developed a model combining economic, ecological, and sociological factors to assess the degree to which economic policies can be used to control invasive plants. Because invasive plants often spread across numerous properties, we explored whether property owners should manage invaders cooperatively as a group by incorporating the negative effects of invader spread in management decisions (collective management) or independently, whereby the negative effects of invasive plant spread are ignored (independent management). Our modeling approach used a dynamic optimization framework, and we applied the model to invader spread using Linaria vulgaris. Model simulations allowed us to determine the optimal management strategy based on net benefits for a range of invader densities. We found that optimal management strategies varied as a function of initial plant densities. At low densities, net benefits were high for both collective and independent management to eradicate the invader, suggesting the importance of early detection and eradication. At moderate densities, collective management led to faster and more frequent invader eradication compared to independent management. When we used a financial penalty to ensure that independent properties were managed collectively, we found that the penalty would be most feasible when levied on a property's perimeter boundary to control spread among properties. At the highest densities, the optimal management strategy was "do nothing" because the economic costs of removal were too high relative to the benefits of removal. Spatial variation in L. vulgaris densities resulted in different optimal management strategies for neighboring properties, making a formal economic policy to encourage invasive species removal critical. To accomplish the management and enforcement of these economic policies, we discuss modification of existing agencies and infrastructure. Finally, a sensitivity analysis revealed that lowering the economic cost of invader removal would strongly increase the probability of invader eradication. Taken together, our results provide quantitative insight into management decisions and economic policy instruments that can encourage invasive species removal across a social landscape.

Estimating suitable environments for invasive plant species across large landscapes: a remote sensing strategy using Landsat 7 ETM+

USGS Publications Warehouse

Young, Kendal E.; Abbott, Laurie B.; Caldwell, Colleen A.; Schrader, T. Scott

2013-01-01

The key to reducing ecological and economic damage caused by invasive plant species is to locate and eradicate new invasions before they threaten native biodiversity and ecological processes. We used Landsat Enhanced Thematic Mapper Plus imagery to estimate suitable environments for four invasive plants in Big Bend National Park, southwest Texas, using a presence-only modeling approach. Giant reed (Arundo donax), Lehmann lovegrass (Eragrostis lehmanniana), horehound (Marrubium vulgare) and buffelgrass (Pennisteum ciliare) were selected for remote sensing spatial analyses. Multiple dates/seasons of imagery were used to account for habitat conditions within the study area and to capture phenological differences among targeted species and the surrounding landscape. Individual species models had high (0.91 to 0.99) discriminative ability to differentiate invasive plant suitable environments from random background locations. Average test area under the receiver operating characteristic curve (AUC) ranged from 0.91 to 0.99, indicating that plant predictive models exhibited high discriminative ability to differentiate suitable environments for invasive plant species from random locations. Omission rates ranged from <1.0 to 18%. We demonstrated that useful models estimating suitable environments for invasive plants may be created with <50 occurrence locations and that reliable modeling using presence-only datasets can be powerful tools for land managers.

Invasive Processes, Mosaics and the Structure of Helminth Parasite Faunas

USDA-ARS?s Scientific Manuscript database

The biosphere in evolutionary and ecological time has been structured by episodes of geographic and host colonization that have determined distributions for complex assemblages of microparasites and macroparasites including helminths circulating among vertebrates. Biological invasion is an intricat...

Applying remote sensing to invasive species science—A tamarisk example

USGS Publications Warehouse

Morisette, Jeffrey T.

2011-01-01

The Invasive Species Science Branch of the Fort Collins Science Center provides research and technical assistance relating to management concerns for invasive species, including understanding how these species are introduced, identifying areas vulnerable to invasion, forecasting invasions, and developing control methods. This fact sheet considers the invasive plant species tamarisk (Tamarix spp), addressing three fundamental questions: *Where is it now? *What are the potential or realized ecological impacts of invasion? *Where can it survive and thrive if introduced? It provides peer-review examples of how the U.S. Geological Survey, working with other federal agencies and university partners, are applying remote-sensing technologies to address these key questions.

Genetic evidence for predominantly hydrochoric gene flow in the invasive riparian plant Impatiens glandulifera (Himalayan balsam)

PubMed Central

Love, Heather M.; Maggs, Christine A.; Murray, Tomás E.; Provan, Jim

2013-01-01

Background and Aims Riparian systems are prone to invasion by alien plant species. The spread of invasive riparian plants may be facilitated by hydrochory, the transport of seeds by water, but while ecological studies have highlighted the possible role of upstream source populations in the establishment and persistence of stands of invasive riparian plant species, population genetic studies have as yet not fully addressed the potential role of hydrochoric dispersal in such systems. Methods A population genetics approach based on a replicated bifurcate sampling design is used to test hypotheses consistent with patterns of unidirectional, linear gene flow expected under hydrochoric dispersal of the invasive riparian plant Impatiens glandulifera in two contrasting river systems. Key results A significant increase in levels of genetic diversity downstream was observed, consistent with the accumulation of propagules from upstream source populations, and strong evidence was found for organization of this diversity between different tributaries, reflecting the dendritic organization of the river systems studied. Conclusions These findings indicate that hydrochory, rather than anthropogenic dispersal, is primarily responsible for the spread of I. glandulifera in these river systems, and this is relevant to potential approaches to the control of invasive riparian plant species. PMID:24169594

Temporal modelling of ballast water discharge and ship-mediated invasion risk to Australia

PubMed Central

Cope, Robert C.; Prowse, Thomas A. A.; Ross, Joshua V.; Wittmann, Talia A.; Cassey, Phillip

2015-01-01

Biological invasions have the potential to cause extensive ecological and economic damage. Maritime trade facilitates biological invasions by transferring species in ballast water, and on ships' hulls. With volumes of maritime trade increasing globally, efforts to prevent these biological invasions are of significant importance. Both the International Maritime Organization and the Australian government have developed policy seeking to reduce the risk of these invasions. In this study, we constructed models for the transfer of ballast water into Australian waters, based on historic ballast survey data. We used these models to hindcast ballast water discharge over all vessels that arrived in Australian waters between 1999 and 2012. We used models for propagule survival to compare the risk of ballast-mediated propagule transport between ecoregions. We found that total annual ballast discharge volume into Australia more than doubled over the study period, with the vast majority of ballast water discharge and propagule pressure associated with bulk carrier traffic. As such, the ecoregions suffering the greatest risk are those associated with the export of mining commodities. As global marine trade continues to increase, effective monitoring and biosecurity policy will remain necessary to combat the risk of future marine invasion events. PMID:26064643

Community Ecology of Container Mosquitoes (Diptera: Culicidae) in Virginia Following Invasion by Aedes japonicus

PubMed Central

ARMISTEAD, JENNIFER S.; NISHIMURA, NAOYA; ARIAS, JORGE R.; LOUNIBOS, L. PHILIP

2012-01-01

The success of an invasive species in a new region depends on its interactions with ecologically similar resident species. Invasions by disease vector mosquitoes are important as they may have ecological and epidemiological consequences. Potential interactions of a recent invasive mosquito, Aedes japonicus Theobald, with resident species in Virginia were evaluated by sampling larvae from containers and trapping adults. Distinct species compositions were observed for artificial containers and rock pools, with Ae. albopictus most abundant in the former and Ae. japonicus in the latter. However, these two species were found to co-occur in 21.2% of containers sampled. Among the six mosquito species most common in containers from May through September, 2006, only interspecific associations of Ae.japonicus with Aedesalbopictus(Skuse) and Aedestriseriatus(Say) were significant, and both were negative. In addition to differences in habitat preference, mean crowding estimates suggest that interspecific repulsion may contribute to the significant negative associations observed between these species. High relative abundances of late instars and pupae of Ae. japonicus seem to provide this species with a mechanism of evading competition with Ae. albopictus, facilitating their coexistence in artificial containers. Although annual fluctuations were observed, trends in adult populations over a 6-yr period provide no evidence of declines. In summary, this survey of diverse container types and all life stages provided only limited evidence for competitive displacements or reductions of resident container species by Ae. japonicus, as observed elsewhere in its invasive range. PMID:23270159

Chemical ecology of Halyomorpha halys: Discoveries and applications

USDA-ARS?s Scientific Manuscript database

There have been notable and significant advances in elucidating the chemical ecology of the invasive Halyomorpha halys (Hemiptera: Pentatomidae), brown marmorated stink bug. This highly destructive and polyphagous pest is originally from Korea, China, and Japan, but was accidentally introduced into ...

Invasive plants affect prairie soil biology

USDA-ARS?s Scientific Manuscript database

Non-native or exotic plants often cause ecological and environmental damage in ecosystems where they invade and become established. These invasive plants may be the most serious threat to plant diversity in prairies, especially those in scattered remnants, which may be particularly vulnerable to rap...

Ecology of cryptic invasions: latitudinal segregation among Watersipora (Bryozoa) species

EPA Science Inventory

Watersipora is an invasive genus of bryozoans, easily dispersed by fouled vessels. We examined Cytochrome c oxidase subunit I haplotypes from introduced populations on the US Pacific coastline to investigate geographic segregation of species and/or haplotypes. In California, the ...

Proceedings, XV U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2004

Treesearch

Kurt W., ed. Gottschalk

2005-01-01

Contains 61 abstracts and papers of oral and poster presentations on gypsy moth and other invasive species biology, molecular biology, ecology, impacts, and management presented at the annual U. S. Department of Agriculture Interagency Research Forum on Gypsy Moth and Other Invasive Species. The online version contains two additional papers that were not available at...

Niche conservatism as an emerging principle in ecology and conservation biology.

PubMed

Wiens, John J; Ackerly, David D; Allen, Andrew P; Anacker, Brian L; Buckley, Lauren B; Cornell, Howard V; Damschen, Ellen I; Jonathan Davies, T; Grytnes, John-Arvid; Harrison, Susan P; Hawkins, Bradford A; Holt, Robert D; McCain, Christy M; Stephens, Patrick R

2010-10-01

The diversity of life is ultimately generated by evolution, and much attention has focused on the rapid evolution of ecological traits. Yet, the tendency for many ecological traits to instead remain similar over time [niche conservatism (NC)] has many consequences for the fundamental patterns and processes studied in ecology and conservation biology. Here, we describe the mounting evidence for the importance of NC to major topics in ecology (e.g. species richness, ecosystem function) and conservation (e.g. climate change, invasive species). We also review other areas where it may be important but has generally been overlooked, in both ecology (e.g. food webs, disease ecology, mutualistic interactions) and conservation (e.g. habitat modification). We summarize methods for testing for NC, and suggest that a commonly used and advocated method (involving a test for phylogenetic signal) is potentially problematic, and describe alternative approaches. We suggest that considering NC: (1) focuses attention on the within-species processes that cause traits to be conserved over time, (2) emphasizes connections between questions and research areas that are not obviously related (e.g. invasives, global warming, tropical richness), and (3) suggests new areas for research (e.g. why are some clades largely nocturnal? why do related species share diseases?). 2010 Blackwell Publishing Ltd/CNRS.

River networks as ecological corridors: A coherent ecohydrological perspective

NASA Astrophysics Data System (ADS)

Rinaldo, Andrea; Gatto, Marino; Rodriguez-Iturbe, Ignacio

2018-02-01

This paper draws together several lines of argument to suggest that an ecohydrological framework, i.e. laboratory, field and theoretical approaches focused on hydrologic controls on biota, has contributed substantially to our understanding of the function of river networks as ecological corridors. Such function proves relevant to: the spatial ecology of species; population dynamics and biological invasions; the spread of waterborne disease. As examples, we describe metacommunity predictions of fish diversity patterns in the Mississippi-Missouri basin, geomorphic controls imposed by the fluvial landscape on elevational gradients of species' richness, the zebra mussel invasion of the same Mississippi-Missouri river system, and the spread of proliferative kidney disease in salmonid fish. We conclude that spatial descriptions of ecological processes in the fluvial landscape, constrained by their specific hydrologic and ecological dynamics and by the ecosystem matrix for interactions, i.e. the directional dispersal embedded in fluvial and host/pathogen mobility networks, have already produced a remarkably broad range of significant results. Notable scientific and practical perspectives are thus open, in the authors' view, to future developments in ecohydrologic research.

A review of fire effects on vegetation and soils in the Great Basin region: response and ecological site characteristics

USGS Publications Warehouse

Miller, Richard F.; Chambers, Jeanne C.; Pyke, David A.; Pierson, Fred B.; Williams, C. Jason

2013-01-01

This review synthesizes the state of knowledge on fire effects on vegetation and soils in semi-arid ecosystems in the Great Basin Region, including the central and northern Great Basin and Range, Columbia River Basin, and the Snake River Plain. We summarize available literature related to: (1) the effects of environmental gradients, ecological site, and vegetation characteristics on resilience to disturbance and resistance to invasive species; (2) the effects of fire on individual plant species and communities, biological soil crusts, seed banks, soil nutrients, and hydrology; and (3) the role of fire severity, fire versus fire surrogate treatments, and post-fire grazing in determining ecosystem response. From this, we identify knowledge gaps and present a framework for predicting plant successional trajectories following wild and prescribed fires and fire surrogate treatments. Possibly the three most important ecological site characteristics that influence a site’s resilience (ability of the ecological site to recover from disturbance) and resistance to invasive species are soil temperature/moisture regimes and the composition and structure of vegetation on the ecological site just prior to the disturbance event.

The Invasive Species Forecasting System: A Space-Based Decision Support Infrastructure for Managing Biological Invasions

NASA Astrophysics Data System (ADS)

Most, N. N.; Kendig, D.; Wichman, K.; Pollack, N.; Ilagan, A.; Morisette, J. T.; Pedelty, J. A.; Tilmes, C.; Smith, J. A.; Pfister, R.; Schnase, J. L.; Stohgren, T. J.; Crosier, C.; Graham, J.; Newman, G.; Kalkhan, M. A.; Reich, R.

2004-12-01

The spread of invasive species is one of the most daunting environmental, economic, and human-health problems facing the United States and the World today. It is one of several grand challenge environmental problems being addressed by NASA's Science Mission Directorate through a national application partnership with the US Geological Survey. NASA and USGS are working together to develop a National Invasive Species Forecasting System (ISFS) for the management and control of invasive species on Department of Interior and adjacent lands. As part of this effort, we are using NASA's EOS Clearing House (ECHO) framework to create an Invasive Species Data Service (ISDS). The ISDS will be a networked service that integrates a suite of NASA remote sensing data providers with the ecological field data resources of the National Biological Information Infrastructure (NBII). Aggregated ISDS data will feed directly into ISFS analysis routines to produce landscape-scale predictive maps of species distributions. ISDS and the ECHO framework thus provide an efficient interface between existing NASA data systems and decision support systems that are the province of federal agencies and other national organizations. The effort significantly broadens the use of NASA data in managing the Nation's invasive species threat. In this talk, we will describe the NASA/USGS invasive species partnership, provide an overview of the Invasive Species Forecasting System, and show how we are using ECHO technologies as the middle-ware framework for a comprehensive Invasive Species Data Service.

Stress in biological invasions: Introduced invasive grey squirrels increase physiological stress in native Eurasian red squirrels.

PubMed

Santicchia, Francesca; Dantzer, Ben; van Kesteren, Freya; Palme, Rupert; Martinoli, Adriano; Ferrari, Nicola; Wauters, Lucas Armand

2018-05-23

Invasive alien species can cause extinction of native species through processes including predation, interspecific competition for resources or disease-mediated competition. Increases in stress hormones in vertebrates may be associated with these processes and contribute to the decline in survival or reproduction of the native species. Eurasian red squirrels (Sciurus vulgaris) have gone extinct across much of the British Isles and parts of Northern Italy following the introduction of North American invasive grey squirrels (Sciurus carolinensis). We extracted glucocorticoid metabolites from faecal samples to measure whether the presence of the invasive species causes an increase in physiological stress in individuals of the native species. We show that native red squirrels in seven sites where they co-occurred with invasive grey squirrels had glucocorticoid concentrations that were three times higher than those in five sites without the invasive species. Moreover, in a longitudinal study, stress hormones in native red squirrels increased after colonisation by grey squirrels. When we experimentally reduced the abundance of the invasive grey squirrels, the concentration of faecal glucocorticoid metabolites in co-occurring red squirrels decreased significantly between pre- and postremoval periods. Hence, we found that the invasive species acts as a stressor which significantly increases the concentrations of glucocorticoids in the native species. Given that sustained elevations in glucocorticoids could reduce body growth and reproductive rate, our results are consistent with previous studies where the co-occurrence of the invasive grey squirrel was associated with smaller size and lower reproductive output in red squirrels. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.

BOOK REVIEW OF "ECOLOGICAL EFFECTS OF ROADS"

EPA Science Inventory

Throughout the world, roads have become a permanent part of our environment. The ecological effects of roads and traffic are as consequential as other topical issues such as losses in biological diversity and damage by exotic and invasive species. However, this issue has usuall...

Spread of the Tiger: Global Risk of Invasion by the Mosquito Aedes albopictus

PubMed Central

BENEDICT, MARK Q.; LEVINE, REBECCA S.; HAWLEY, WILLIAM A.; LOUNIBOS, L. PHILIP

2008-01-01

Aedes albopictus, commonly known as the Asian tiger mosquito, is currently the most invasive mosquito in the world. It is of medical importance due to its aggressive daytime human-biting behavior and ability to vector many viruses, including dengue, LaCrosse, and West Nile. Invasions into new areas of its potential range are often initiated through the transportation of eggs via the international trade in used tires. We use a genetic algorithm, Genetic Algorithm for Rule Set Production (GARP), to determine the ecological niche of Ae. albopictus and predict a global ecological risk map for the continued spread of the species. We combine this analysis with risk due to importation of tires from infested countries and their proximity to countries that have already been invaded to develop a list of countries most at risk for future introductions and establishments. Methods used here have potential for predicting risks of future invasions of vectors or pathogens. PMID:17417960

Simulation of rapid ecological change in Lake Ontario

USGS Publications Warehouse

McKenna, James E.; Chalupnicki, Marc; Dittman, Dawn E.; Watkins, James M.

2017-01-01

Lower trophic level processes are integral to proper functioning of large aquatic ecosystems and have been disturbed in Lake Ontario by various stressors including exotic species. The invasion of benthic habitats by dreissenid mussels has led to systemic changes and native faunal declines. Size-dependent physiological rates, spatial differences and connectivity, competition, and differential population dynamics among invertebrate groups contributed to the change and system complexity. We developed a spatially explicit, individual-based mechanistic model of the benthic ecosystem in Lake Ontario, with coupling to the pelagic system, to examine ecosystem dynamics and effects of dreissenid mussel invasion and native fauna losses. Benthic organisms were represented by functional groups; filter-feeders (i.e., dreissenid mussels), surface deposit-feeders (e.g., native amphipod Diporeia spp.), and deposit-feeders (e.g., oligochaetes and other burrowers). The model was stable, represented ecological structure and function effectively, and reproduced observed effects of the mussel invasion. Two hypotheses for causes of Diporeia loss, competition or disease-like mortality, were tested. Simple competition for food did not explain observed declines in native surface deposit-feeders during the filter-feeder invasion. However, the elevated mortality scenario supports a disease-like cause for loss of the native amphipod, with population changes in various lake areas and altered benthic biomass transfers. Stabilization of mussel populations and possible recovery of the native, surface-deposit feeding amphipod were predicted. Although further research is required on forcing functions, model parameters, and natural conditions, the model provides a valuable tool to help managers understand the benthic system and plan for response to future disruptions.

The ethological trap: functional and numerical responses of highly efficient invasive predators driving prey extinctions.

PubMed

Spencer, Ricky-John; Van Dyke, James U; Thompson, Michael B

2016-10-01

Ecological traps are threats to organisms, and exist in a range of biological systems. A subset of ecological trap theory is the "ethological trap," whereby behaviors canalized by past natural selection become traps when environments change rapidly. Invasive predators are major threats to imperiled species and their ability to exploit canalized behaviors of naive prey is particularly important for the establishment of the predator and the decline of the native prey. Our study uses ecological theory to demonstrate that invasive predator controls require shifts in management priorities. Total predation rate (i.e., total response) is the product of both the functional response and numerical response of predators to prey. Functional responses are the changes in the rate of prey consumption by individual predators, relative to prey abundance. Numerical responses are the aggregative rates of prey consumption by all predators relative to prey density, which change with predator density via reproduction or migration, in response to changes in prey density. Traditional invasive predator management methods focus on reducing predator populations, and thus manage for numerical responses. These management efforts fail to manage for functional responses, and may not eliminate impacts of highly efficient individual predators. We explore this problem by modeling the impacts of functional and numerical responses of invasive foxes depredating imperiled Australian turtle nests. Foxes exhibit exceptionally efficient functional responses. A single fox can destroy >95% of turtle nests in a nesting area, which eliminates juvenile recruitment. In this case, the ethological trap is the "Arribada" nesting strategy, an emergent behavior whereby most turtles in a population nest simultaneously in the same nesting grounds. Our models show that Arribada nesting events do not oversaturate foxes, and small numbers of foxes depredate all of the nests in a given Arribada. Widely scattering nests may reduce fox predation rates, but the long generation times of turtles combined with their rapid recent decline suggests that evolutionary responses in nesting strategy may be unlikely. Our study demonstrates that reducing populations of highly efficient invasive predators is insufficient for preserving native prey species. Instead, management must reduce individual predator efficiency, independent of reducing predator population size. © 2016 by the Ecological Society of America.

Management applications of discontinuity theory

USGS Publications Warehouse

Angeler, David G.; Allen, Craig R.; Barichievy, Chris; Eason, Tarsha; Garmestani, Ahjond S.; Graham, Nicholas A.J.; Granholm, Dean; Gunderson, Lance H.; Knutson, Melinda; Nash, Kirsty L.; Nelson, R. John; Nystrom, Magnus; Spanbauer, Trisha; Stow, Craig A.; Sundstrom, Shana M.

2015-01-01

Human impacts on the environment are multifaceted and can occur across distinct spatiotemporal scales. Ecological responses to environmental change are therefore difficult to predict, and entail large degrees of uncertainty. Such uncertainty requires robust tools for management to sustain ecosystem goods and services and maintain resilient ecosystems.We propose an approach based on discontinuity theory that accounts for patterns and processes at distinct spatial and temporal scales, an inherent property of ecological systems. Discontinuity theory has not been applied in natural resource management and could therefore improve ecosystem management because it explicitly accounts for ecological complexity.Synthesis and applications. We highlight the application of discontinuity approaches for meeting management goals. Specifically, discontinuity approaches have significant potential to measure and thus understand the resilience of ecosystems, to objectively identify critical scales of space and time in ecological systems at which human impact might be most severe, to provide warning indicators of regime change, to help predict and understand biological invasions and extinctions and to focus monitoring efforts. Discontinuity theory can complement current approaches, providing a broader paradigm for ecological management and conservation.

Stochastic ecological network occupancy (SENO) models: a new tool for modeling ecological networks across spatial scales

USGS Publications Warehouse

Lafferty, Kevin D.; Dunne, Jennifer A.

2010-01-01

Stochastic ecological network occupancy (SENO) models predict the probability that species will occur in a sample of an ecological network. In this review, we introduce SENO models as a means to fill a gap in the theoretical toolkit of ecologists. As input, SENO models use a topological interaction network and rates of colonization and extinction (including consumer effects) for each species. A SENO model then simulates the ecological network over time, resulting in a series of sub-networks that can be used to identify commonly encountered community modules. The proportion of time a species is present in a patch gives its expected probability of occurrence, whose sum across species gives expected species richness. To illustrate their utility, we provide simple examples of how SENO models can be used to investigate how topological complexity, species interactions, species traits, and spatial scale affect communities in space and time. They can categorize species as biodiversity facilitators, contributors, or inhibitors, making this approach promising for ecosystem-based management of invasive, threatened, or exploited species.

[Ecological memory and its potential applications in ecology: a review].

PubMed

Sun, Zhong-yu; Ren, Hai

2011-03-01

Ecological memory (EM) is defined as the capability of the past states or experiences of a community to influence the present or future ecological responses of the community. As a relatively new concept, EM has received considerable attention in the study of ecosystem structure and function, such as community succession, ecological restoration, biological invasion, and natural resource management. This review summarized the definition, components, and categories of EM, and discussed the possible mechanisms and affecting factors of EM. Also, the potential applications of EM were proposed, in order to further understand the mechanisms of community succession and to guide ecological restoration.

Patterns of trophic niche divergence between invasive and native fishes in wild communities are predictable from mesocosm studies.

PubMed

Tran, Thi Nhat Quyen; Jackson, Michelle C; Sheath, Danny; Verreycken, Hugo; Britton, J Robert

2015-07-01

Ecological theory attempts to predict how impacts for native species arise from biological invasions. A fundamental question centres on the feeding interactions of invasive and native species: whether invasion will result in increased interspecific competition, which would result in negative consequences for the competing species, or trophic niche divergence, which would facilitate the invader's integration into the community and their coexistence with native species. Here, the feeding interactions of a highly invasive fish, topmouth gudgeon Pseudorasbora parva, with three native and functionally similar fishes were studied to determine whether patterns of either niche overlap or divergence detected in mesocosm experiments were apparent between the species at larger spatial scales. Using stable isotope analysis, their feeding relationships were assessed initially in the mesocosms (1000 L) and then in small ponds (<400 m(2) ) and large ponds (>600 m(2) ). In the mesocosms, a consistent pattern of trophic niche divergence was evident between the sympatric fishes, with niches shifting further apart in isotopic space than suggested in allopatry, revealing that sharing of food resources was limited. Sympatric P. parva also had a smaller niche than their allopatric populations. In eight small ponds where P. parva had coexisted for several years with at least one of the fish species used in the mesocosms, strong patterns of niche differentiation were also apparent, with P. parva always at a lower trophic position than the other fishes, as also occurred in the mesocosms. Where these fishes were sympatric within more complex fish communities in the large ponds, similar patterns were also apparent, with strong evidence of trophic niche differentiation. Aspects of the ecological impacts of P. parva invasion for native communities in larger ponds were consistent with those in the mesocosm experiments. Their invasion resulted in divergence in trophic niches, partly due to their reduced niche widths when in sympatry with other species, facilitating their coexistence in invaded ecosystems. Our study highlights the utility of controlled mesocosm studies for predicting the trophic relationships that can develop from introductions of non-native species into more complex ecosystems and at larger spatial scales. © 2015 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Management applications of discontinuity theory | Science ...

EPA Pesticide Factsheets

1.Human impacts on the environment are multifaceted and can occur across distinct spatiotemporal scales. Ecological responses to environmental change are therefore difficult to predict, and entail large degrees of uncertainty. Such uncertainty requires robust tools for management to sustain ecosystem goods and services and maintain resilient ecosystems. 2.We propose an approach based on discontinuity theory that accounts for patterns and processes at distinct spatial and temporal scales, an inherent property of ecological systems. Discontinuity theory has not been applied in natural resource management and could therefore improve ecosystem management because it explicitly accounts for ecological complexity. 3.Synthesis and applications. We highlight the application of discontinuity approaches for meeting management goals. Specifically, discontinuity approaches have significant potential to measure and thus understand the resilience of ecosystems, to objectively identify critical scales of space and time in ecological systems at which human impact might be most severe, to provide warning indicators of regime change, to help predict and understand biological invasions and extinctions and to focus monitoring efforts. Discontinuity theory can complement current approaches, providing a broader paradigm for ecological management and conservation This manuscript provides insight on using discontinuity approaches to aid in managing complex ecological systems. In part

The negative ecological impacts of a globally introduced species decrease with time since introduction.

PubMed

Závorka, Libor; Buoro, Mathieu; Cucherousset, Julien

2018-05-25

While there is a long-history of biological invasions and their ecological impacts have been widely demonstrated across taxa and ecosystems, our knowledge on the temporal dynamic of these impacts remains extremely limited. Using a meta-analytic approach, we investigated how the ecological impacts of non-native brown trout (Salmo trutta), a model species with a 170-year long and well-documented history of intentional introductions across the globe, vary with time since introduction. We first observed significant negative ecological impacts immediately after the species introduction. Second, we found that the negative ecological impacts decrease with time since introduction and that the average ecological impacts become non-significant more than one century after introduction. This pattern was consistent across other ecological contexts (i.e. geographical location, levels of biological organisation, and methodological approach). However, overall negative ecological impacts were more pronounced at the individual and population levels and in experimental studies. While the mechanisms leading to this decrease remain to be determined, our results indicate that rapid response of native organisms (e.g. adaptation, but also local extinction) may play an important role in this dynamic. Changes in native species traits and local extinction can have important conservation implications. Therefore, we argue that the decline of the negative ecological impacts over time should not be used as an argument to neglect the negative impacts of biological invasions. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

II. Pathogens

Treesearch

Ned B. Klopfenstein; Brian W. Geils

2011-01-01

Invasive fungal pathogens have caused immeasurably large ecological and economic damage to forests. It is well known that invasive fungal pathogens can cause devastating forest diseases (e.g., white pine blister rust, chestnut blight, Dutch elm disease, dogwood anthracnose, butternut canker, Scleroderris canker of pines, sudden oak death, pine pitch canker) (Maloy 1997...

Impact of invasive aquatic macrophytes on the population and behavioral ecology of mosquitoes (Diptera: Culicidae)

USDA-ARS?s Scientific Manuscript database

A field survey, three outdoor cage enclosure experiments, and laboratory studies were conducted to elucidate the impact of the invasive aquatic weeds Eichhornia crassipes (floating water hyacinth), Ludwigia hexapetala (emergent water yellow-primrose), and Egeria densa (submersed Brazilian waterweed)...

Invasive woolly adelgid appears to drive seasonal hemlock and carcass inputs to a detritus-based stream

Treesearch

John S. Kominoski; Catherine M. Pringle; Becky A. Ball

2008-01-01

Ecosystems are experiencing rapid ecological changes due to human-driven alterations in climate, land-use, nutrient availability, and introduction of pests and pathogens. Many of these environmental changes are predicted to result in non-random loss of species that will alter community composition (VITOUSEK et a1. 1997, LOREAU et a1. 2001, ELLISON et a1. 200S). For...

Water Hyacinth in China: A Sustainability Science-Based Management Framework

NASA Astrophysics Data System (ADS)

Lu, Jianbo; Wu, Jianguo; Fu, Zhihui; Zhu, Lei

2007-12-01

The invasion of water hyacinth ( Eichhornia crassipes) has resulted in enormous ecological and economic consequences worldwide. Although the spread of this weed in Africa, Australia, and North America has been well documented, its invasion in China is yet to be fully documented. Here we report that since its introduction about seven decades ago, water hyacinth has infested many water bodies across almost half of China’s territory, causing a decline of native biodiversity, alteration of ecosystem services, deterioration of aquatic environments, and spread of diseases affecting human health. Water hyacinth infestations have also led to enormous economic losses in China by impeding water flows, paralyzing navigation, and damaging irrigation and hydroelectricity facilities. To effectively control the rampage of water hyacinth in China, we propose a sustainability science-based management framework that explicitly incorporates principles from landscape ecology and Integrated Pest Management. This framework emphasizes multiple-scale long-term monitoring and research, integration among different control techniques, combination of control with utilization, and landscape-level adaptive management. Sustainability science represents a new, transdisciplinary paradigm that integrates scientific research, technological innovation, and socioeconomic development of particular regions. Our proposed management framework is aimed to broaden the currently dominant biological control-centered view in China and to illustrate how sustainability science can be used to guide the research and management of water hyacinth.

Land management in the Anthropocene: Is history still relevant?

USGS Publications Warehouse

Safford, Hugh D.; Betancourt, Julio L.; Hayward, Gregory D.; Wiens, John A.; Regan, Claudia M.

2008-01-01

Ecological restoration, conservation, and land management are often based on comparisons with reference sites or time periods, which are assumed to represent “natural” or “properly functioning” conditions. Such reference conditions can provide a vision of the conservation or management goal and a means to measure progress toward that vision. Although historical ecology has been used successfully to guide resource management in many parts of the world, the continuing relevance of history is now being questioned. Some scientists doubt that lessons from the past can inform management in what may be a dramatically different future, given profound climate change, accelerated land use, and an onslaught of plant and animal invasions.

The Invasive Brazilian Pepper Tree (Schinus terebinthifolius) Is Colonized by a Root Microbiome Enriched With Alphaproteobacteria and Unclassified Spartobacteria.

PubMed

Dawkins, Karim; Esiobu, Nwadiuto

2018-01-01

Little is known about the rhizosphere microbiome of the Brazilian pepper tree (BP) - a noxious category 1 invasive plant inducing an enormous economic and ecological toll in Florida. Some invasive plants have been shown to drastically change the soil microbiome compared to other native plants. The rhizobacteria community structure of BP, two Florida native plants ( Hamelia patens and Bidens alba ) and bulk soils were characterized across six geographical sites. Although all 19 well-known and 10 poorly described phyla were observed in all plant rhizospheres, BP contained the least total bacterial abundance (OTUs) with a distinct bacteria community structure and clustering patterns differing significantly (pCOA and PERMANOVA) from the natives and bulk soil. The BP rhizosphere community contained the highest overall Proteobacteria diversity (Shannon's diversity 3.25) in spite of a twofold reduction in richness of the Gammaproteobacteria. Remarkably, the invasive BP rhizosphere was highly enriched with Alphaproteobacteria, dominated by Rhizobiales, including Rhodoplanes and Bradyrhizobiaceae. Also, the relative abundance of Spartobacteria under BP rhizosphere was more than twice that of native plants and bulk soil; featuring unique members of the family Chthoniobacteraceae (DA101 genus). The trend was different for the family Pedosphaerae in the phylum Verrucomicrobia where the abundance declined under BP (26%) compared to (33-66%) for the H. patens native plant and bulk soil. BP shared the lowest number of unique phylotypes with bulk soil (146) compared to the other native plants with bulk soil ( B. alba - 222, H. patens - 520) suggestive of its capacity to overcome biotic resistance. Although there were no specific biomarkers found, taken together, our data suggests that the occurrence of key bacteria groups across multiple taxonomic ranks provides a somewhat consistent profile of the invasive BP rhizo-community. Furthermore, based on the observed prevalence of a bacteria group (Spartobacteria - Chthoniobacteraceae - DA101); we propose that they have a possible role in BP biology. Our results emphasize the need to further investigate the potential value of "unique phylotypes" in the rhizosphere relative to bulk soil as an ecological tool for monitoring plant-cover/invasion history; or even detecting exotic plants with invasion tendencies.

An assessment of invasive plant species monitored by the Northern Research Station Forest Inventory and Analysis Program, 2005 through 2010

Treesearch

Cassandra M. Kurtz

2013-01-01

Invasive plant species are a worldwide concern due to the high ecological and economic costs associated with their presence. This document describes the plant characteristics and regional distribution of the 50 invasive plant species monitored from 2005 through 2010 on forested Phase 2 (P2) Forest Inventory and Analysis (FIA) plots in the 24 states of the Northern...

UNC Pembroke Laser Scanning Confocal Microscopy Facility

DTIC Science & Technology

2016-04-29

cultures. INVASIVE FIRE ANTS Professor Lisa Kelly of UNC Pembroke has been trained on the new confocal system. Dr. Kelly’s research...interest in the trophic ecology of the invasive fire ant has begun to benefit from the wide field view and long working distances of a confocal imaging...of protein clearance pathways in living brain tissue cultures. INVASIVE FIRE ANTS Professor Lisa Kelly of UNC Pembroke has been trained on

Geographical and taxonomic biases in invasion ecology.

PubMed

Pysek, Petr; Richardson, David M; Pergl, Jan; Jarosík, Vojtech; Sixtová, Zuzana; Weber, Ewald

2008-05-01

Invasive alien species come from most taxonomic groups, and invasion biology is searching for robust cross-taxon generalizations and principles. An analysis of 2,670 papers dealing with 892 invasive species showed that all major groups of invaders are well studied, but that most information on the mechanisms of invasion has emerged from work on a limited number of the most harmful invaders. A strong geographical bias, with Africa and Asia understudied, inhibits a balanced understanding of invasion, because we might be lacking knowledge of specific invasion mechanisms from poorly studied, regionally specific habitats. International cooperation is required to achieve a more geographically balanced picture of biological invasions. Invasive species with the greatest impact are best studied, but more studies of species that are naturalized but not (yet) invasive are needed to improve understanding of the mechanisms acting during the naturalization phase of invasions and leading to successful invasion.

Biological Invasions of Geminiviruses: Case Study of TYLCV and Bemisia tabaci in Reunion Island

PubMed Central

Péréfarres, Frédéric; Thierry, Magali; Becker, Nathalie; Lefeuvre, Pierre; Reynaud, Bernard; Delatte, Hélène; Lett, Jean-Michel

2012-01-01

In the last 20 years, molecular ecology approaches have proven to be extremely useful to identify and assess factors associated with viral emerging diseases, particularly in economically and socially important tropical crops such as maize (maize streak disease) and cassava (cassava mosaic disease). Molecular ecology approaches were applied in Reunion Island to analyze the epidemic of tomato yellow leaf curl disease, which has been affecting the island since the end of the 1990s. Before the invasive biotype B (currently known as Middle East-Asia Minor 1 cryptic species) of Bemisia tabaci spread across the world, Reunion Island (South West Indian Ocean) only hosted an indigenous biotype of B. tabaci, Ms (currently known as Indian Ocean cryptic species). Wild hybrids between invasive and indigenous species were subsequently characterized over multiple generations. Endosymbiont analysis of the hybrid population indicated that matings were non-random. Similarly, while no indigenous begomoviruses have ever been reported on Reunion Island, the two main strains of one of the most damaging and emerging plant viruses in the world, the Mild and Israel strains of the Tomato yellow leaf curl virus (TYLCV-Mld and TYLCV-IL), were introduced in 1997 and 2004 respectively. While these introductions extensively modified the agricultural landscape of Reunion Island, they also provided an invaluable opportunity to study the ecological and genetic mechanisms involved in biological invasion and competition. PMID:23235470

[Applied ecology: retrospect and prospect].

PubMed

He, Xingyuan; Zeng, Dehui

2004-10-01

Applied ecology is evolved into a principal part of modern ecology that rapidly develops. The major stimulus for the development of applied ecology roots in seeking the solutions for the problems of human populations, resources and environments. Through four decades, the science of applied ecology has been becoming a huge group of disciplines. The future for the applied ecology should concern more with human-influenced and managed ecosystems, and acknowledge humans as the components of ecosystems. Nowadays and in future, the top-priorities in applied ecology should include following fields: sustainable ecosystems and biosphere, ecosystem services and ecological design, ecological assessment of genetically modified organisms, ecology of biological invasions, epidemical ecology, ecological forecasting, ecological process and its control. The authors believe that the comprehensive and active research hotspots coupled some new traits would occur around these fields in foreseeable future.

Culturally induced range infilling of eastern redcedar: a problem in ecology, an ecological problem, or both?

USGS Publications Warehouse

Streit Krug, Aubrey; Uden, Daniel R.; Allen, Craig R.; Twidwell, Dirac

2017-01-01

The philosopher John Passmore distinguished between (1) “problems in ecology,” or what we might call problems in scientific understanding of ecological change, and (2) “ecological problems,” or what we might call problems faced by societies due to ecological change. The spread of eastern redcedar (Juniperus virginiana) and conversion of the central and southern Great Plains of North America to juniper woodland might be categorized as a problem in ecology, an ecological problem, or both. Here, we integrate and apply two interdisciplinary approaches to problem-solving—social-ecological systems thinking and ecocriticism—to understand the role of human culture in recognizing, driving, and responding to cedar’s changing geographic distribution. We interpret the spread of cedar as a process of culturally induced range infilling due to the ongoing social-ecological impacts of colonization, analyze poetic literary texts to clarify the concepts that have so far informed different cultural values related to cedar, and explore the usefulness of diverse interdisciplinary collaborations and knowledge for addressing social-ecological challenges like cedar spread in the midst of rapidly unfolding global change. Our examination suggests that it is not only possible, but preferable, to address cedar spread as both a scientific and a social problem. Great Plains landscapes are teetering between grassland and woodland, and contemporary human societies both influence and choose how to cope with transitions between these ecological states. We echo previous studies in suggesting that human cultural values about stability and disturbance, especially cultural concepts of fire, will be primary driving factors in determining future trajectories of change on the Great Plains. Although invasion-based descriptors of cedar spread may be useful in ecological research and management, language based on the value of restraint could provide a common vocabulary for effective cross-disciplinary and interdisciplinary communication about the relationship between culture and cedar, as well as an ethical framework for cross-cultural communication, decision-making, and management.

Disease introduction is associated with a phase transition in bighorn sheep demographics.

PubMed

Manlove, Kezia; Cassirer, E Frances; Cross, Paul C; Plowright, Raina K; Hudson, Peter J

2016-10-01

Ecological theory suggests that pathogens are capable of regulating or limiting host population dynamics, and this relationship has been empirically established in several settings. However, although studies of childhood diseases were integral to the development of disease ecology, few studies show population limitation by a disease affecting juveniles. Here, we present empirical evidence that disease in lambs constrains population growth in bighorn sheep (Ovis canadensis) based on 45 years of population-level and 18 years of individual-level monitoring across 12 populations. While populations generally increased (λ = 1.11) prior to disease introduction, most of these same populations experienced an abrupt change in trajectory at the time of disease invasion, usually followed by stagnant-to-declining growth rates (λ = 0.98) over the next 20 years. Disease-induced juvenile mortality imposed strong constraints on population growth that were not observed prior to disease introduction, even as adult survival returned to pre-invasion levels. Simulations suggested that models including persistent disease-induced mortality in juveniles qualitatively matched observed population trajectories, whereas models that only incorporated all-age disease events did not. We use these results to argue that pathogen persistence may pose a lasting, but under-recognized, threat to host populations, particularly in cases where clinical disease manifests primarily in juveniles. © 2016 by the Ecological Society of America.

3-D Technology Approaches for Biological Ecologies

NASA Astrophysics Data System (ADS)

Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team

Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).

The devil is in the details: genetic variation in introduced populations and its contributions to invasion.

PubMed

Dlugosch, Katrina M; Anderson, Samantha R; Braasch, Joseph; Cang, F Alice; Gillette, Heather D

2015-05-01

The influence of genetic variation on invasion success has captivated researchers since the start of the field of invasion genetics 50 years ago. We review the history of work on this question and conclude that genetic variation-as surveyed with molecular markers-appears to shape invasion rarely. Instead, there is a significant disconnect between marker assays and ecologically relevant genetic variation in introductions. We argue that the potential for adaptation to facilitate invasion will be shaped by the details of genotypes affecting phenotypes, and we highlight three areas in which we see opportunities to make powerful new insights. (i) The genetic architecture of adaptive variation. Traits shaped by large-effect alleles may be strongly impacted by founder events yet more likely to respond to selection when genetic drift is strong. Large-effect loci may be especially relevant for traits involved in biotic interactions. (ii) Cryptic genetic variation exposed during invasion. Introductions have strong potential to uncover masked variation due to alterations in genetic and ecological environments. (iii) Genetic interactions during admixture of multiple source populations. As divergence among sources increases, positive followed by increasingly negative effects of admixture should be expected. Although generally hypothesized to be beneficial during invasion, admixture is most often reported among sources of intermediate divergence, supporting the possibility that incompatibilities among divergent source populations might be limiting their introgression. Finally, we note that these details of invasion genetics can be coupled with comparative demographic analyses to link genetic changes to the evolution of invasiveness itself. © 2015 John Wiley & Sons Ltd.

Invasive carnivores alter ecological function and enhance complementarity in scavenger assemblages on ocean beaches.

PubMed

Brown, Marion B; Schlacher, Thomas A; Schoeman, David S; Weston, Michael A; Huijbers, Chantal M; Olds, Andrew D; Connolly, Rod M

2015-10-01

Species composition is expected to alter ecological function in assemblages if species traits differ strongly. Such effects are often large and persistent for nonnative carnivores invading islands. Alternatively, high similarity in traits within assemblages creates a degree of functional redundancy in ecosystems. Here we tested whether species turnover results in functional ecological equivalence or complementarity, and whether invasive carnivores on islands significantly alter such ecological function. The model system consisted of vertebrate scavengers (dominated by raptors) foraging on animal carcasses on ocean beaches on two Australian islands, one with and one without invasive red foxes (Vulpes vulpes). Partitioning of scavenging events among species, carcass removal rates, and detection speeds were quantified using camera traps baited with fish carcasses at the dune-beach interface. Complete segregation of temporal foraging niches between mammals (nocturnal) and birds (diurnal) reflects complementarity in carrion utilization. Conversely, functional redundancy exists within the bird guild where several species of raptors dominate carrion removal in a broadly similar way. As predicted, effects of red foxes were large. They substantially changed the nature and rate of the scavenging process in the system: (1) foxes consumed over half (55%) of all carrion available at night, compared with negligible mammalian foraging at night on the fox-free island, and (2) significant shifts in the composition of the scavenger assemblages consuming beach-cast carrion are the consequence of fox invasion at one island. Arguably, in the absence of other mammalian apex predators, the addition of red foxes creates a new dimension of functional complementarity in beach food webs. However, this functional complementarity added by foxes is neither benign nor neutral, as marine carrion subsidies to coastal red fox populations are likely to facilitate their persistence as exotic carnivores.

Differences in native soil ecology associated with invasion of the exotic annual chenopod, Halgeton glomeratus

USGS Publications Warehouse

Duda, Jeffrey J.; Freeman, D. Carl; Emlen, John M.; Belnap, Jayne; Kitchen, Stanley G.; Zak, John C.; Sobek, Edward; Tracy, Mary; Montante, James

2003-01-01

Various biotic and abiotic components of soil ecology differed significantly across an area whereHalogeton glomeratus is invading a native winterfat, [ Krascheninnikovia (= Ceratoides) lanata] community. Nutrient levels were significantly different among the native, ecotone, and exotic-derived soils. NO3, P, K, and Na all increased as the cover of halogeton increased. Only Ca was highest in the winterfat area. A principal components analysis, conducted separately for water-soluble and exchangeable cations, revealed clear separation between halogeton- and winterfat-derived soils. The diversity of soil bacteria was highest in the exotic, intermediate in the ecotone, and lowest in the native community. Although further studies are necessary, our results offer evidence that invasion by halogeton alters soil chemistry and soil ecology, possibly creating conditions that favor halogeton over native plants.

Non-invasive reproductive and stress endocrinology in amphibian conservation physiology

PubMed Central

Narayan, E. J.

2013-01-01

Non-invasive endocrinology utilizes non-invasive biological samples (such as faeces, urine, hair, aquatic media, and saliva) for the quantification of hormones in wildlife. Urinary-based enzyme immunoassay (EIA) and radio-immunoassay have enabled the rapid quantification of reproductive and stress hormones in amphibians (Anura: Amphibia). With minimal disturbance, these methods can be used to assess the ovarian and testicular endocrine functions as well as physiological stress in captive and free-living populations. Non-invasive endocrine monitoring has therefore greatly advanced our knowledge of the functioning of the stress endocrine system (the hypothalamo–pituitary–interrenal axis) and the reproductive endocrine system (the hypothalamo–pituitary–gonadal axis) in the amphibian physiological stress response, reproductive ecology, health and welfare, and survival. Biological (physiological) validation is necessary for obtaining the excretory lag time of hormone metabolites. Urinary-based EIA for the major reproductive hormones, estradiol and progesterone in females and testosterone in males, can be used to track the reproductive hormone profiles in relationship to reproductive behaviour and environmental data in free-living anurans. Urinary-based corticosterone metabolite EIA can be used to assess the sublethal impacts of biological stressors (such as invasive species and pathogenic diseases) as well as anthropogenic induced environmental stressors (e.g. extreme temperatures) on free-living populations. Non-invasive endocrine methods can also assist in the diagnosis of success or failure of captive breeding programmes by measuring the longitudinal patterns of changes in reproductive hormones and corticosterone within captive anurans and comparing the endocrine profiles with health records and reproductive behaviour. This review paper focuses on the reproductive and the stress endocrinology of anurans and demonstrates the uses of non-invasive endocrinology for advancing amphibian conservation physiology. It also provides key technical considerations for future research that will increase the accuracy and reliability of the data and the value of non-invasive endocrinology within the conceptual framework of conservation physiology. PMID:27293595

El control biologico de plagas(Biological control of pests)

USDA-ARS?s Scientific Manuscript database

In this work some ecological principles that drive applied biocontrol and agent selection are discussed. Subjects such as specificity evaluations, host shifts and species invasiveness are analyzed under the light of ecological theory. The main assertions are: 1. biological control is a safe and bene...

Testing fundamental ecological concepts with a Pythium-Prunus pathosystem

USDA-ARS?s Scientific Manuscript database

The study of plant-pathogen interactions has enabled tests of basic ecological concepts on plant community assembly (Janzen-Connell Hypothesis) and plant invasion (Enemy Release Hypothesis). We used a field experiment to (#1) test whether Pythium effects depended on host (seedling) density and/or d...

Integrating ecology and genetics to address Acari invasions

USDA-ARS?s Scientific Manuscript database

Because of their small size and tolerance to many of the control procedures used for a wide variety of commodities, Acari species have become one of the fastest, unwanted pest travelers since the beginning of this century. This special issue includes eleven studies on adventive and invasive Acari sp...

Ecological and Economic Impacts and Invasion Management Strategies for the European Green Crab (2008)

EPA Pesticide Factsheets

The goals of this case study were to estimate the European green crab’s current and historical impacts on ecosystem services on the East Coast of the United States and to estimate the European green crab’s current and potential future impacts from invasion

Proceedings - Symposium on cheatgrass invasion, shrub die-off, and other aspects of shrub biology and management

Treesearch

E. Durant McArthur; Evan M. Romney; Stanley D. Smith; Paul T. Tueller

1990-01-01

Includes 45 papers and accounts of field trips from a symposium focused on a recent shrub die-off phenomenon and a perennial problem, cheatgrass invasion, on western rangelands. Contributions also cover shrub establishment, shrub ecosystem ecology and physiology, and plant and shrub ecosystems.

Teaching complex ecological concepts through a demonstration garden Biodiversity, invasions and conservation in practice

USDA-ARS?s Scientific Manuscript database

Biodiversity encompasses the variety within and between species in an environment. Native communities host a diverse array of species and interactions between members. Invasions by non-native species reduce biodiversity and a community’s ability to support diverse assemblages, and are one of the lar...

Marine invasions enter the genomic era: three lessons from the past, and the way forward

EPA Science Inventory

The expanding scale and increasing rate of marine biological invasions has been documented since the early 20th century. Besides their global ecological and economic impacts, non-indigenous species (NIS) also have attracted much attention as opportunities to explore important eco...

Predicting invasion in grassland ecosystems: Is exotic dominance the real embarrassment of richness?

USDA-ARS?s Scientific Manuscript database

For two centuries there has been a perception that while exotic species are dominant in many areas, others remain largely unaffected. This unquantified observation suggests a fundamental ecological question: why do exotics dominate some locations and not others? While invasions are clearly important...

76 FR 36896 - Salmon-Challis National Forest, ID; Forestwide Invasive Plant Treatment Environmental Impact...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-23

... DEPARTMENT OF AGRICULTURE Forest Service Salmon-Challis National Forest, ID; Forestwide Invasive... to the biological diversity and ecological integrity within and outside the Salmon-Challis National... loss of recreational opportunities. Within the 3,108,904 acres of the of the Salmon-Challis National...

Effect of the Internet Commerce on Dispersal Modes of Invasive Alien Species

PubMed Central

Lenda, Magdalena; Skórka, Piotr; Knops, Johannes M. H.; Moroń, Dawid; Sutherland, William J.; Kuszewska, Karolina; Woyciechowski, Michał

2014-01-01

The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal. PMID:24932498

The more the better? The role of polyploidy in facilitating plant invasions

PubMed Central

te Beest, Mariska; Le Roux, Johannes J.; Richardson, David M.; Brysting, Anne K.; Suda, Jan; Kubešová, Magdalena; Pyšek, Petr

2012-01-01

Background Biological invasions are a major ecological and socio-economic problem in many parts of the world. Despite an explosion of research in recent decades, much remains to be understood about why some species become invasive whereas others do not. Recently, polyploidy (whole genome duplication) has been proposed as an important determinant of invasiveness in plants. Genome duplication has played a major role in plant evolution and can drastically alter a plant's genetic make-up, morphology, physiology and ecology within only one or a few generations. This may allow some polyploids to succeed in strongly fluctuating environments and/or effectively colonize new habitats and, thus, increase their potential to be invasive. Scope We synthesize current knowledge on the importance of polyploidy for the invasion (i.e. spread) of introduced plants. We first aim to elucidate general mechanisms that are involved in the success of polyploid plants and translate this to that of plant invaders. Secondly, we provide an overview of ploidal levels in selected invasive alien plants and explain how ploidy might have contributed to their success. Conclusions Polyploidy can be an important factor in species invasion success through a combination of (1) ‘pre-adaptation’, whereby polyploid lineages are predisposed to conditions in the new range and, therefore, have higher survival rates and fitness in the earliest establishment phase; and (2) the possibility for subsequent adaptation due to a larger genetic diversity that may assist the ‘evolution of invasiveness’. Alternatively, polyploidization may play an important role by (3) restoring sexual reproduction following hybridization or, conversely, (4) asexual reproduction in the absence of suitable mates. We, therefore, encourage invasion biologists to incorporate assessments of ploidy in their studies of invasive alien species. PMID:22040744

Effect of the internet commerce on dispersal modes of invasive alien species.

PubMed

Lenda, Magdalena; Skórka, Piotr; Knops, Johannes M H; Moroń, Dawid; Sutherland, William J; Kuszewska, Karolina; Woyciechowski, Michał

2014-01-01

The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal.

Establishment of two invasive crustaceans (Copepoda: Harpacticoida) on the nearshore sands of Lake Michigan

USGS Publications Warehouse

Horvath, Thomas G.; Whitman, Richard L.; Last, Laurel L.

2001-01-01

Benthic copepods (Copepoda: Harpacticoida) in the nearshore sediments of southern Lake Michigan appear to be dominated by two new invasive species. We report the first occurrence in North America of Schizopera borutzkyi Montschenko, a native to the Danube River delta, and Heteropsyllus nr. nunni, likely a new species that is morphologically similar to the marine species Heteropsyllus nunni and represents the first occurrence of this genus in freshwater. Schizopera borutzkyi is a euryhaline species occurring in shallow sands in its native habitat and in deeper sands (6-15 m) in southern Lake Michigan. Based on the absence of these species from previous studies, we suggest that they are recent introductions. Heteropsyllus nr. nunni dominated (55-100%) the harpacticoid abundance to depths of 9 m, but S. borutzkyi comprised 75% of the harpacticoid abundance at 15 m. Native harpacticoids were always greatly outnumbered by invasive harpacticoids in our samples, which suggests that the natives are being replaced rapidly or that the invasive species are finding unused resources. The ecological implications of these introductions are not known, but these invasions may represent continued 'invasional meltdown' in Lake Michigan.

Landscape-scale GPP and carbon density inform patterns and impacts of an invasive tree across wet forests of Hawaii.

PubMed

Barbosa, Jomar M; Asner, Gregory P; Hughes, R Flint; Johnson, M Tracy

2017-03-01

Plant invasion typically occurs within a landscape-scale framework of abiotic and biotic conditions, often resulting in emergent feedbacks among environment, ecosystem functions, and the dominance of invasive species. Understanding the mechanisms underlying successful invasions is an important component of conservation and management efforts, but this has been poorly investigated in a spatially explicit manner. Knowing where and why invasion patterns change throughout the landscape enables managers to use context-specific controls on the spread of invasive species. Using high-resolution airborne imaging spectroscopy, we studied plant performance in growth within and across landscapes to examine the dominance and spatial distribution of an invasive tree, Psidium cattleianum (strawberry guava), in heterogeneous environmental conditions of a submontane Hawaiian tropical forest. We assessed invader performance using the GPP ratio index, which is the relative difference in remotely sensed estimates of gross primary productivity between canopies of guava and canopies of the invaded plant community. In addition, we used airborne LiDAR data to evaluate the impacts of guava invasion on the forest aboveground carbon density in different environments. Structural equation modeling revealed that substrate type and elevation above sea level interact and amplify landscape-scale differences in productivity between the invasive species and the host plant community (GPP ratio); differences that ultimately control levels of dominance of guava. We found shifts in patterns of forest carbon storage based on both gradual increase of invader dominance and changes in environmental conditions. Overall, our results demonstrate that the remotely sensed index defined as the GPP ratio provided an innovative spatially explicit approach to track and predict the success of invasive plants based in their canopy productivity, particularly within a landscape-scale framework of varying environmental factors such as soils and elevation. This approach may help managers accurately predict where invaders of forests, scrublands, or grasslands are likely to exhibit high levels of dominance before the environment is fully invaded. © 2016 by the Ecological Society of America.

Evolution of biogeography in the 21st Century - Development of a North Pacific Nonindigenous Species Database

EPA Science Inventory

Aquatic invasive species are one of the major ecological threats to the ecological integrity of estuarine and near-coastal waters. However, lack of systematic inventories of nonindigenous species across the North Pacific countries limits our ability to assess how the extent of i...

Trophic overlap between native and invasive stream crayfish

USGS Publications Warehouse

Magoulick, Daniel D.; Piercey, Glenn L.

2016-01-01

We examined trophic dynamics of a stream food web where invasive Orconectes neglectus appear to be displacing native O. eupunctus in the Spring River drainage of the Ozark Highlands, Missouri and Arkansas, USA. We collected crayfish species and possible food sources seasonally from a site of sympatry on the South Fork Spring River. We determined diet overlap and potential for competition between O. eupunctus and O. neglectus, and investigated seasonal variation using carbon and nitrogen stable isotope analyses and gut content analyses. Gut content analysis showed both species of crayfish consumed mainly detritus during summer and spring, with other prey categories varying by species and season. Stable isotope analysis showed that O. eupunctus and O. neglectus relied on invertebrates as a major energy and nutrient source throughout summer, autumn, and spring, and the two species showed differences in their stable isotope signatures during spring and summer, but not autumn. Given the trophic overlap between O. eupunctus and O. neglectus, there is a potential for the two species to compete for food and to be ecologically redundant. Ecological redundancy can lead to reduced effects on ecosystem function post-invasion, and therefore examining ecological redundancy of potential invaders should be a conservation priority.

An efficient swarm intelligence approach to feature selection based on invasive weed optimization: Application to multivariate calibration and classification using spectroscopic data

NASA Astrophysics Data System (ADS)

Sheykhizadeh, Saheleh; Naseri, Abdolhossein

2018-04-01

Variable selection plays a key role in classification and multivariate calibration. Variable selection methods are aimed at choosing a set of variables, from a large pool of available predictors, relevant to the analyte concentrations estimation, or to achieve better classification results. Many variable selection techniques have now been introduced among which, those which are based on the methodologies of swarm intelligence optimization have been more respected during a few last decades since they are mainly inspired by nature. In this work, a simple and new variable selection algorithm is proposed according to the invasive weed optimization (IWO) concept. IWO is considered a bio-inspired metaheuristic mimicking the weeds ecological behavior in colonizing as well as finding an appropriate place for growth and reproduction; it has been shown to be very adaptive and powerful to environmental changes. In this paper, the first application of IWO, as a very simple and powerful method, to variable selection is reported using different experimental datasets including FTIR and NIR data, so as to undertake classification and multivariate calibration tasks. Accordingly, invasive weed optimization - linear discrimination analysis (IWO-LDA) and invasive weed optimization- partial least squares (IWO-PLS) are introduced for multivariate classification and calibration, respectively.

GIS-based rapid-assessment of bighead carp Hypophthalmichthys nobilis (Richardson, 1845) suitability in reservoirs

USGS Publications Warehouse

Long, James M.; Liang, Yu; Shoup, Daniel E.; Dzialowski, Andrew R.; Bidwell, Joseph R.

2014-01-01

Broad-scale niche models are good for examining the potential for invasive species occurrences, but can fall short in providing managers with site-specific locations for monitoring. Using Oklahoma as an example, where invasive bighead carp (Hypophthalmichthys nobilis) are established in certain reservoirs, but predicted to be widely distributed based on broad-scale niche models, we cast bighead carp reproductive ecology in a site-specific geospatial framework to determine their potential establishment in additional reservoirs. Because bighead carp require large, long free-flowing rivers with suitable hydrology for reproduction but can persist in reservoirs, we considered reservoir tributaries with mean annual daily discharge ≥8.5 cubic meters per second (m3 /s) and quantified the length of their unimpeded portions. In contrast to published broad-scale niche models that identified nearly the entire state as susceptible to invasion, our site-specific models showed that few reservoirs in Oklahoma (N = 9) were suitable for bighead carp establishment. Moreover, this method was rapid and identified sites that could be prioritized for increased study or scrutiny. Our results highlight the importance of considering the environmental characteristics of individual sites, which is often the level at which management efforts are implemented when assessing susceptibility to invasion.

An efficient swarm intelligence approach to feature selection based on invasive weed optimization: Application to multivariate calibration and classification using spectroscopic data.

PubMed

Sheykhizadeh, Saheleh; Naseri, Abdolhossein

2018-04-05

Variable selection plays a key role in classification and multivariate calibration. Variable selection methods are aimed at choosing a set of variables, from a large pool of available predictors, relevant to the analyte concentrations estimation, or to achieve better classification results. Many variable selection techniques have now been introduced among which, those which are based on the methodologies of swarm intelligence optimization have been more respected during a few last decades since they are mainly inspired by nature. In this work, a simple and new variable selection algorithm is proposed according to the invasive weed optimization (IWO) concept. IWO is considered a bio-inspired metaheuristic mimicking the weeds ecological behavior in colonizing as well as finding an appropriate place for growth and reproduction; it has been shown to be very adaptive and powerful to environmental changes. In this paper, the first application of IWO, as a very simple and powerful method, to variable selection is reported using different experimental datasets including FTIR and NIR data, so as to undertake classification and multivariate calibration tasks. Accordingly, invasive weed optimization - linear discrimination analysis (IWO-LDA) and invasive weed optimization- partial least squares (IWO-PLS) are introduced for multivariate classification and calibration, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

Monitoring the Invasion of Spartina alterniflora Using Very High Resolution Unmanned Aerial Vehicle Imagery in Beihai, Guangxi (China)

PubMed Central

Wan, Huawei; Wang, Qiao; Jiang, Dong; Yang, Yipeng; Liu, Xiaoman

2014-01-01

Spartina alterniflora was introduced to Beihai, Guangxi (China), for ecological engineering purposes in 1979. However, the exceptional adaptability and reproductive ability of this species have led to its extensive dispersal into other habitats, where it has had a negative impact on native species and threatens the local mangrove and mudflat ecosystems. To obtain the distribution and spread of Spartina alterniflora, we collected HJ-1 CCD imagery from 2009 and 2011 and very high resolution (VHR) imagery from the unmanned aerial vehicle (UAV). The invasion area of Spartina alterniflora was 357.2 ha in 2011, which increased by 19.07% compared with the area in 2009. A field survey was conducted for verification and the total accuracy was 94.0%. The results of this paper show that VHR imagery can provide details on distribution, progress, and early detection of Spartina alterniflora invasion. OBIA, object based image analysis for remote sensing (RS) detection method, can enable control measures to be more effective, accurate, and less expensive than a field survey of the invasive population. PMID:24892066

Monitoring the invasion of Spartina alterniflora using very high resolution unmanned aerial vehicle imagery in Beihai, Guangxi (China).

PubMed

Wan, Huawei; Wang, Qiao; Jiang, Dong; Fu, Jingying; Yang, Yipeng; Liu, Xiaoman

2014-01-01

Spartina alterniflora was introduced to Beihai, Guangxi (China), for ecological engineering purposes in 1979. However, the exceptional adaptability and reproductive ability of this species have led to its extensive dispersal into other habitats, where it has had a negative impact on native species and threatens the local mangrove and mudflat ecosystems. To obtain the distribution and spread of Spartina alterniflora, we collected HJ-1 CCD imagery from 2009 and 2011 and very high resolution (VHR) imagery from the unmanned aerial vehicle (UAV). The invasion area of Spartina alterniflora was 357.2 ha in 2011, which increased by 19.07% compared with the area in 2009. A field survey was conducted for verification and the total accuracy was 94.0%. The results of this paper show that VHR imagery can provide details on distribution, progress, and early detection of Spartina alterniflora invasion. OBIA, object based image analysis for remote sensing (RS) detection method, can enable control measures to be more effective, accurate, and less expensive than a field survey of the invasive population.

Habitat-specific population structure in native western flower thrips Frankliniella occidentalis (Insecta, Thysanoptera).

PubMed

Brunner, P C; Frey, J E

2010-04-01

Invasions by pest organisms are among the main challenges for sustainable crop protection. They pose a serious threat to crop production by introducing a highly unpredictable element to existing crop protection strategies. The western flower thrips Frankliniella occidentalis (Insecta, Thysanoptera) managed to invade ornamental greenhouses worldwide within < 25 years. To shed light on possible genetic and/or ecological factors that may have been responsible for this invasion success, we studied the population genetic structure of western flower thrips in its native range in western North America. Analysis of nucleotide sequence variation and variation at microsatellite loci revealed the existence of two habitat-specific phylogenetic lineages (ecotypes) with allopatric distribution. One lineage is associated with hot/dry climates, the second lineage is restricted to cool/moist climates. We speculate that the ecological niche segregation found in this study may be among the key factors determining the invasion potential of western flower thrips.

Multidimensional spatial characterization of plant invasions in 'El Pinacate y Gran Desierto de Altar' Biosphere Reserve

NASA Astrophysics Data System (ADS)

Sanchez Flores, Erick

Invasive species are considered an agent of ecological change with more significant effects than global warming. Exotic plant invasions threaten biodiversity and ecosystem viability worldwide. Their effects in the Sonoran Desert ecosystems are a growing concern among ecologists and land managers. We hypothesized that highly dynamic desert environments are unstable, therefore more vulnerable to invasion by exotic plant species. To test this hypothesis we used a multidimensional approach to assess the spatial distribution of two exotic species: Brassica tournefortii (Saharan mustard) and Schismus arabicus (Arabian grass), in a portion of 'El Pinacate y Gran Desierto de Altar' Biosphere Reserve (PBR) in northwestern Sonora, Mexico. This approach combined genetic algorithms, geographic information systems, field methods, statistical analysis, and remote sensing modeling at multiple spatial and temporal scales to predict and test the current and potential distribution of the invasives over dynamic landscapes. Predicted probability of invasion was influenced strongly by human factors: Road networks were the strongest predictors of presence, revealing the potential importance of humans as vectors of invasiveness. Dynamic landscapes, associated mostly with vegetation losses, were detected spectrally in the eastern portion of the study area, very likely associated with past agricultural and current grazing activity. Combined models of high probability for invasion by B. tournefortii and S. arabicus over dynamic landscapes were tested against confirmed locations of the invasives and land cover types associated with invasion. Results confirmed the hypothesis of the study and suggest that more dynamic landscapes are more prone to invasion by these two exotic plants in the PBR. B. tournefortii was found associated mostly with landscapes occupied by microphyllous desert scrub and grassland, as well as sarcocaulescent desert scrub. S. arabicus was found more abundantly in the flat low lands occupied by microphyllous and crassicaulescent desert scrub. These relationships cannot, however, be conclusive and require further investigation due to the complex ecology of these invasives.

Invasion of a dominant floral resource: effects on the floral community and pollination of native plants.

PubMed

Goodell, Karen; Parker, Ingrid M

2017-01-01

Through competition for pollinators, invasive plants may suppress native flora. Community-level studies provide an integrative assessment of invasion impacts and insights into factors that influence the vulnerability of different native species. We investigated effects of the nonnative herb Lythrum salicaria on pollination of native species in 14 fens of the eastern United States. We compared visitors per flower for 122 native plant species in invaded and uninvaded fens and incorporated a landscape-scale experiment, removing L. salicaria flowers from three of the invaded fens. Total flower densities were more than three times higher in invaded than uninvaded or removal sites when L. salicaria was blooming. Despite an increase in number of visitors with number of flowers per area, visitors per native flower declined with increasing numbers of flowers. Therefore, L. salicaria invasion depressed visitation to native flowers. In removal sites, visitation to native flowers was similar to uninvaded sites, confirming the observational results and also suggesting that invasion had not generated a persistent build-up of visitor populations. To study species-level impacts, we examined effects of invasion on visitors per flower for the 36 plant species flowering in both invaded and uninvaded fens. On average, the effect of invasion represented about a 20% reduction in visits per flower. We measured the influence of plant traits on vulnerability to L. salicaria invasion using meta-analysis. Bilaterally symmetrical flowers experienced stronger impacts on visitation, and similarity in flower color to L. salicaria weakly intensified competition with the invader for visitors. Finally, we assessed the reproductive consequences of competition with the invader in a dominant flowering shrub, Dasiphora fruticosa. Despite the negative effect of invasion on pollinator visitation in this species, pollen limitation of seed production was not stronger in invaded than in uninvaded sites, suggesting little impact of competition for pollinators on its population demography. Negative effects on pollination of native plants by this copiously flowering invader appeared to be mediated by increases in total flower density that were not matched by increases in pollinator density. The strength of impact was modulated across native species by their floral traits and reproductive ecology. © 2016 The Authors. Ecology, published by Wiley Periodicals, Inc., on behalf of the Ecological Society of America.

Population-Level Metrics of Trophic Structure Based on Stable Isotopes and Their Application to Invasion Ecology

PubMed Central

Jackson, Michelle C.; Donohue, Ian; Jackson, Andrew L.; Britton, J. Robert; Harper, David M.; Grey, Jonathan

2012-01-01

Biological invasions are a significant driver of human-induced global change and many ecosystems sustain sympatric invaders. Interactions occurring among these invaders have important implications for ecosystem structure and functioning, yet they are poorly understood. Here we apply newly developed metrics derived from stable isotope data to provide quantitative measures of trophic diversity within populations or species. We then use these to test the hypothesis that sympatric invaders belonging to the same functional feeding group occupy a smaller isotopic niche than their allopatric counterparts. Two introduced, globally important, benthic omnivores, Louisiana swamp crayfish (Procambarus clarkii) and carp (Cyprinus carpio), are sympatric in Lake Naivasha, Kenya. We applied our metrics to an 8-year data set encompassing the establishment of carp in the lake. We found a strong asymmetric interaction between the two invasive populations, as indicated by inverse correlations between carp abundance and measures of crayfish trophic diversity. Lack of isotopic niche overlap between carp and crayfish in the majority of years indicated a predominantly indirect interaction. We suggest that carp-induced habitat alteration reduced the diversity of crayfish prey, resulting in a reduction in the dietary niche of crayfish. Stable isotopes provide an integrated signal of diet over space and time, offering an appropriate scale for the study of population niches, but few isotope studies have retained the often insightful information revealed by variability among individuals in isotope values. Our population metrics incorporate such variation, are robust to the vagaries of sample size and are a useful additional tool to reveal subtle dietary interactions among species. Although we have demonstrated their applicability specifically using a detailed temporal dataset of species invasion in a lake, they have a wide array of potential ecological applications. PMID:22363724

Population-level metrics of trophic structure based on stable isotopes and their application to invasion ecology.

PubMed

Jackson, Michelle C; Donohue, Ian; Jackson, Andrew L; Britton, J Robert; Harper, David M; Grey, Jonathan

2012-01-01

Biological invasions are a significant driver of human-induced global change and many ecosystems sustain sympatric invaders. Interactions occurring among these invaders have important implications for ecosystem structure and functioning, yet they are poorly understood. Here we apply newly developed metrics derived from stable isotope data to provide quantitative measures of trophic diversity within populations or species. We then use these to test the hypothesis that sympatric invaders belonging to the same functional feeding group occupy a smaller isotopic niche than their allopatric counterparts. Two introduced, globally important, benthic omnivores, Louisiana swamp crayfish (Procambarus clarkii) and carp (Cyprinus carpio), are sympatric in Lake Naivasha, Kenya. We applied our metrics to an 8-year data set encompassing the establishment of carp in the lake. We found a strong asymmetric interaction between the two invasive populations, as indicated by inverse correlations between carp abundance and measures of crayfish trophic diversity. Lack of isotopic niche overlap between carp and crayfish in the majority of years indicated a predominantly indirect interaction. We suggest that carp-induced habitat alteration reduced the diversity of crayfish prey, resulting in a reduction in the dietary niche of crayfish. Stable isotopes provide an integrated signal of diet over space and time, offering an appropriate scale for the study of population niches, but few isotope studies have retained the often insightful information revealed by variability among individuals in isotope values. Our population metrics incorporate such variation, are robust to the vagaries of sample size and are a useful additional tool to reveal subtle dietary interactions among species. Although we have demonstrated their applicability specifically using a detailed temporal dataset of species invasion in a lake, they have a wide array of potential ecological applications.

Biogeography of plant invasions

Treesearch

Dean Pearson; Yvette Ortega

2013-01-01

The fact that most of our worst animal and weed pests come from other continents is no coincidence. Biological invasions are fundamentally a biogeographic phenomenon. That is to say, there is something rather significant about taking an organism from a specific evolutionary history and ecological context and casting it into an entirely new environment that can...

Limited native plant regeneration in novel, exotic-dominated forests on Hawaii

Treesearch

Joseph Mascaro; Kristen K. Becklund; R. Flint Hughes; Stefan A. Schnitzer

2008-01-01

Ecological invasions are amajor driver of global environmental change. When invasions are frequent and prolonged, exotic species can become dominant and ultimately create novel ecosystem types. These ecosystems are now widespread globally. Recent evidence from Puerto Rico suggests that exoticdominated forests can provide suitable regeneration sites for native species...

Use of saltcedar and Utah juniper as fillers in wood–plastic composites

Treesearch

Craig Clemons; Nicole Stark

2007-01-01

Invasive and small-diameter species have become more prevalent, creating numerous environmental and ecological problems. One potential method to control and eliminate invasive species and thereby promote natural rangeland restoration is developing new, value-added uses for them. Saltcedar (Tamarisk ramosissima) and Utah juniper (Juniperus osteosperma) were investigated...

Economic impacts of invasive species in forest past, present, and future

Treesearch

Thomas P. Holmes; Juliann E. Aukema; Betsy Von Holle; Andrew Liebhold; Erin Sills

2009-01-01

Biological invasions by nonnative species are a by-product of economic activities, with the vast majority of nonnative species introduced by trade and transport of products and people. Although most introduced species are relatively innocuous, a few species ultimately cause irreversible economic and ecological impacts, such as the chestnut blight that functionally...

A new perspective on trait differences between native and invasive exotic plants: reply to critique

USDA-ARS?s Scientific Manuscript database

A meta-analysis contrasting morphological and physiological traits of invasive species and native species was conducted using data acquired from journal articles published between the years 1995 and 2010. This study (Leffler et al. 2014, Ecology 95:298-305), generated a comment from Dawson et al. (...

Combining tactics to exploit allee effects for eradication of alien insect populations

Treesearch

David Maxwell Suckling; Patrick C. Tobin; Deborah G. McCullough; Daniel A. Herms

2012-01-01

Invasive species increasingly threaten ecosystems, food production, and human welfare worldwide. Hundreds of eradication programs have targeted a wide range of nonnative insect species to mitigate the economic and ecological impacts of biological invasions. Many such programs used multiple tactics to achieve this goal, but interactions between tactics have received...

Climate analyses to assess risks from invasive forest insects: Simple matching to advanced models

Treesearch

Robert C. Venette

2017-01-01

Purpose of Review. The number of invasive alien insects that adversely affect trees and forests continues to increase as do associated ecological, economic, and sociological impacts. Prevention strategies remain the most cost-effective approach to address the issue, but risk management decisions, particularly those affecting international trade,...

Region-wide ecological responses of arid Wyoming big sagebrush communities to fuel treatments

Treesearch

David A. Pyke; Scott E. Shaff; Andrew I. Lindgren; Eugene W. Schupp; Paul S. Doescher; Jeanne C. Chambers; Jeffrey S. Burnham; Manuela M. Huso

2014-01-01

If arid sagebrush ecosystems lack resilience to disturbances or resistance to annual invasives, then alternative successional states dominated by annual invasives, especially cheatgrass (Bromus tectorum L.), are likely after fuel treatments. We identified six Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle & Young) locations (152-381 mm...

Funding needed for assessments of weed biological control

Treesearch

John L. Maron; Dean E. Pearson; Stephen M. Hovick; Walter P. Carson

2010-01-01

Invasive non-native plants are a serious economic and ecological problem worldwide, and major efforts are therefore devoted to reducing weed abundance in agricultural and natural settings. Effective options for reducing invasive abundance and spread are few, although one common approach is biological control - the introduction of specialist herbivores or pathogens from...

Are native songbird populations affected by non-native plant invasion?

Treesearch

Amanda M. Conover; Christopher K. Williams; Vincent. D' Amico

2011-01-01

Development into forested areas is occurring rapidly across the United States, and many of the remnant forests within suburban landscapes are being fragmented into smaller patches, impacting the quality of this habitat for avian species. An ecological effect linked to forest fragmentation is the invasion of non-native plants into the ecosystem.

The role of the Forest Service in nonnative invasive plant research

Treesearch

Carolyn Hull Sieg; Julie S. Densow; Cynthia D. Huebner; James H. Miller

2010-01-01

In many of our Nation's wildlands, invasive nonnative plants contribute to the endangerment of native species and lead to other severe ecological and financial consequences. Projected trends of increasing human populations and associated development and globalization will contribute to increases in the already high rates of introductions of nonnative plant species...

Population ecology of insect invasions and their management

Treesearch

Andrew M. Liebhold; Patrick C. Tobin

2008-01-01

During the establishment phase of a biological invasion, population dynamics are strongly influenced by Allee effects and stochastic dynamics, both of which may lead to extinction of low-density populations. Allee effects refer to a decline in population growth rate with a decline in abundance and can arise from various mechanisms. Strategies to eradicate newly...

Landscape connectivity influences the establishment of Phytophthora ramorum

Treesearch

Emiko T. Condeso; Ross K. Meentemeyer

2008-01-01

As the emergence of invasive pathogens and their impacts on ecological communities increases, so has the interest in understanding how landscape pattern (in other words the configuration and composition of suitable habitat) affects their establishment and spread. Plant pathogen invasions are inherently spatial, but few studies have demonstrated the role of landscape...

Evidence for ongoing introduction of non-native earthworms in the Washington, DC metropolitan area

Treesearch

Mac A. Callaham; Bruce A. Snyder; Samuel W. James; Erik T. Oberg

2016-01-01

Earthworm introductions and invasions are ongoing, with significant consequences for ecological characteristics and function where populations of invasive species reach high densities. In North America the influx of people, goods and materials to coastal cities has long been recognized to be related to introduction and establishment of...

Effects of the emerald ash borer invasion on the community composition of arthropods associated with ash tree boles

USDA-ARS?s Scientific Manuscript database

Emerald ash borer (EAB), Agrilus planipennis Fairmaire is an invasive non-native wood-boring beetle that has killed hundreds of millions of ash trees (Fraxinus spp.) in North America, and threatens to extirpate the ecological services provided by the genus. Identifying the arthropod community assoc...

A decade of a thrips invasion in China: lessons learned.

PubMed

Wu, Shengyong; Tang, Liangde; Zhang, Xingrui; Xing, Zhenlong; Lei, Zhongren; Gao, Yulin

2017-10-11

The Western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is an invasive polyphagous pest with an expanding global range that damages a wide variety of crops. F. occidentalis was first reported in China from Yunnan province during 2000, and has rapidly expanded its range since then. It is currently distributed across at least 10 provinces in China and has become a particularly devastating pest, causing substantial damage and economic losses. At present, the still heavy reliance on frequent use of insecticides for control of F. occidentalis, has lead to a series of ecological problems stemming from insecticide resistance, interspecific displacement and non-target effects. Thus, integrated pest management (IPM) programmes, multiple complementary tactics, including preventive tactics, biological controls, and judicious use of insecticides will likely provide a viable IPM strategy for control of F. occidentalis in the near future. This review provides an overview for information gained during the 10+ years since the invasion of F. occidentalis into China, reviews lessons that have been learned enhancing our overall understanding of the biology and ecology of F. occidentalis and discusses IPM practices relative to this widespread invasive insect pest.

A nature-based approach for managing the invasive weed species Gutenbergia cordifolia for sustainable rangeland management.

PubMed

Ngondya, Issakwisa B; Munishi, Linus K; Treydte, Anna C; Ndakidemi, Patrick A

2016-01-01

The invasive weed species Gutenbergia cordifolia has been observed to suppress native plants and to dominate more than half of the entire crater floor (250 km 2 ) in the Ngorongoro Conservation Area (NCA). As this species has been found to be toxic to ruminants it might strongly impact animal populations in this ecologically diverse ecosystem. Hence, a nature-based approach is urgently needed to manage its spread. We tested two Desmodium spp extracts applied to G. cordifolia and assessed the latter's germination rate, height, fresh weight and leaf total chlorophyll content after 30 days in both laboratory and screen house experiments. Seedling germination rate was halved by Desmodium uncinatum leaf extract (DuL), particularly under higher concentrations (≥75 %) rather than lower concentrations (≤62.5 %). Likewise, in both laboratory and screen house experiments, germination rate under DuL treatments declined with increasing concentrations. Seedling height, fresh weight and leaf total chlorophyll content (Chl) were also most strongly affected by DuL treatments rather than D. uncinatum root extract, Desmodium intortum leaf extract or D. intortum root extract treatments. Generally, seedlings treated with higher DuL concentrations were half as tall, had one-third the weight and half the leaf Chl content compared to those treated with lower concentrations. Our study shows a novel technique that can be applied where G. cordifolia may be driving native flora and fauna to local extinction. Our data further suggest that this innovative approach is both ecologically safe and effective and that D. uncinatum can be sustainably used to manage invasive plants, and thus, to improve rangeland productivity.

Biology, ecology and management of Elaeagnus angustifolia L. (Russian olive) in western North America

USGS Publications Warehouse

Katz, G.L.; Shafroth, P.B.

2003-01-01

Elaeagnus angustifolia (Russian olive) is an alien tree that is increasingly common in riparian habitats of western North America. This paper reviews the pertinent scientific literature in order to determine the status of E. angustifolia as a riparian invader and to suggest ecological reasons for its success. Elaeagnus angustifolia meets the biogeographic, spread, and impact criteria for invasive species. Ecological characteristics likely enabling its invasiveness include adaptation to the physical environmental conditions that characterize semi-arid riparian habitats, lack of intense pressure from herbivores, and tolerance of the competitive effects of established vegetation. We believe that the success of this species is at least partly due to its ability to take advantage of the reduced levels of physical disturbance that characterize riparian habitats downstream from dams. Control of E. angustifolia is likely to be most promising where natural river flow regimes remain relatively intact.

Validated methodology for quantifying infestation levels of dreissenid mussels in environmental DNA (eDNA) samples.

PubMed

Peñarrubia, Luis; Alcaraz, Carles; Vaate, Abraham Bij de; Sanz, Nuria; Pla, Carles; Vidal, Oriol; Viñas, Jordi

2016-12-14

The zebra mussel (Dreissena polymorpha Pallas, 1771) and the quagga mussel (D. rostriformis Deshayes, 1838) are successful invasive bivalves with substantial ecological and economic impacts in freshwater systems once they become established. Since their eradication is extremely difficult, their detection at an early stage is crucial to prevent spread. In this study, we optimized and validated a qPCR detection method based on the histone H2B gene to quantify combined infestation levels of zebra and quagga mussels in environmental DNA samples. Our results show specific dreissenid DNA present in filtered water samples for which microscopic diagnostic identification for larvae failed. Monitoring a large number of locations for invasive dreissenid species based on a highly specific environmental DNA qPCR assay may prove to be an essential tool for management and control plans focused on prevention of establishment of dreissenid mussels in new locations.

Validated methodology for quantifying infestation levels of dreissenid mussels in environmental DNA (eDNA) samples

PubMed Central

Peñarrubia, Luis; Alcaraz, Carles; Vaate, Abraham bij de; Sanz, Nuria; Pla, Carles; Vidal, Oriol; Viñas, Jordi

2016-01-01

The zebra mussel (Dreissena polymorpha Pallas, 1771) and the quagga mussel (D. rostriformis Deshayes, 1838) are successful invasive bivalves with substantial ecological and economic impacts in freshwater systems once they become established. Since their eradication is extremely difficult, their detection at an early stage is crucial to prevent spread. In this study, we optimized and validated a qPCR detection method based on the histone H2B gene to quantify combined infestation levels of zebra and quagga mussels in environmental DNA samples. Our results show specific dreissenid DNA present in filtered water samples for which microscopic diagnostic identification for larvae failed. Monitoring a large number of locations for invasive dreissenid species based on a highly specific environmental DNA qPCR assay may prove to be an essential tool for management and control plans focused on prevention of establishment of dreissenid mussels in new locations. PMID:27966602

Trait-fitness relationships determine how trade-off shapes affect species coexistence.

PubMed

Ehrlich, Elias; Becks, Lutz; Gaedke, Ursula

2017-12-01

Trade-offs between functional traits are ubiquitous in nature and can promote species coexistence depending on their shape. Classic theory predicts that convex trade-offs facilitate coexistence of specialized species with extreme trait values (extreme species) while concave trade-offs promote species with intermediate trait values (intermediate species). We show here that this prediction becomes insufficient when the traits translate non-linearly into fitness which frequently occurs in nature, e.g., an increasing length of spines reduces grazing losses only up to a certain threshold resulting in a saturating or sigmoid trait-fitness function. We present a novel, general approach to evaluate the effect of different trade-off shapes on species coexistence. We compare the trade-off curve to the invasion boundary of an intermediate species invading the two extreme species. At this boundary, the invasion fitness is zero. Thus, it separates trait combinations where invasion is or is not possible. The invasion boundary is calculated based on measurable trait-fitness relationships. If at least one of these relationships is not linear, the invasion boundary becomes non-linear, implying that convex and concave trade-offs not necessarily lead to different coexistence patterns. Therefore, we suggest a new ecological classification of trade-offs into extreme-favoring and intermediate-favoring which differs from a purely mathematical description of their shape. We apply our approach to a well-established model of an empirical predator-prey system with competing prey types facing a trade-off between edibility and half-saturation constant for nutrient uptake. We show that the survival of the intermediate prey depends on the convexity of the trade-off. Overall, our approach provides a general tool to make a priori predictions on the outcome of competition among species facing a common trade-off in dependence of the shape of the trade-off and the shape of the trait-fitness relationships. © 2017 by the Ecological Society of America.

Keystone predators (eastern newts, Notophthalmus viridescens) reduce the impacts of an aquatic invasive species

USGS Publications Warehouse

Smith, Kimberly G.

2006-01-01

Predation, competition, and their interaction are known to be important factors that influence the structure of ecological communities. In particular, in those cases where a competitive hierarchy exists among prey species, the presence of certain keystone predators can result in enhanced diversity in the prey community. However, little is known regarding the influence of keystone predator presence on invaded prey communities. Given the widespread occurrence of invasive species and substantial concern regarding their ecological impacts, studies on this topic are needed. In this study I used naturalistic replications of an experimental tadpole assemblage to assess the influence of predatory eastern newts, Notophthalmus viridescens, on the outcome of interspecific competition among native and nonindigenous tadpoles. When newts were absent, the presence of the tadpoles of one invasive species, the Cuban treefrog, Osteopilus septentrionalis, resulted in decreased survival and growth rate of the dominant native species, Bufo terrestris, and dominance of the tadpole assemblage by O. septentrionalis. However, the presence of one adult newt generally reduced or eliminated the negative impacts of O. septentrionalis tadpoles, resulting in comparable survival and performance of native species in invaded and noninvaded treatments. Differential mortality among the tadpole species suggests that newts preyed selectively on O. septentrionalis tadpoles, supporting the hypothesis that newts acted as keystone predators in the invaded assemblage. The presence of nonindigenous larval cane toads, Bufo marinus, did not significantly affect native species, and this species was not negatively affected by the presence of newts. Collectively, these results suggest that eastern newts significantly modified the competitive hierarchy of the invaded tadpole assemblage and reduced the impacts of a competitively superior invasive species. If general, these results suggest that the presence of certain species may be an essential factor regulating the ecological impacts of biological invasions.

Proceedings from the Southwest Region Threatened, Endangered, and At-Risk Species Workshop Held in Tucson, Arizona on October 22-25, 2007

DTIC Science & Technology

2007-10-01

synthesis of ecology , evolution , and paleontology. Int. J. Plant Sci. 168, 729–749. Fahrig, L. (2003). Effects of habitat fragmentation on...from its habitat to feed and breed, including inter- ecological interactions and migratory issues. To generalize, available data suggests that there...Background Non-native invasive plants and animals are recognized as significant threats to economic and ecological values throughout the

Do invasive quagga mussels alter CO2 dynamics in the Laurentian Great Lakes?

NASA Astrophysics Data System (ADS)

Lin, Peng; Guo, Laodong

2016-12-01

The Laurentian Great Lakes have experienced unprecedented ecological and environmental changes, especially after the introduction of invasive quagga mussel (Dreissena rostriformis bugensis). While impacts on ecological functions have been widely recognized, the response of carbon dynamics to invasive species remains largely unknown. We report new CO2 data showing significant increases in pCO2 (up to 800 μatm in Lake Michigan) and CO2 emission fluxes in most of the Great Lakes compared to those prior to or during the early stage of the colonization of invasive quagga mussels. The increased CO2 supersaturation is most prominent in Lakes Huron and Michigan, followed by Lakes Ontario and Erie, but no evident change was observed in Lake Superior. This trend mirrors the infestation extent of invasive quagga mussels in the Great Lakes and is consistent with the decline in primary production and increase in water clarity observed pre- and post-Dreissena introduction, revealing a close linkage between invasive species and carbon dynamics. The Great Lakes have become a significant CO2 source to the atmosphere, emitting >7.7 ± 1.0 Tg-C annually, which is higher than the organic carbon burial rate in global inland-seas and attesting to the significant role of the Laurentian Great Lakes in regional/global CO2 budget and cycling.

Five potential consequences of climate change for invasive species.

PubMed

Hellmann, Jessica J; Byers, James E; Bierwagen, Britta G; Dukes, Jeffrey S

2008-06-01

Scientific and societal unknowns make it difficult to predict how global environmental changes such as climate change and biological invasions will affect ecological systems. In the long term, these changes may have interacting effects and compound the uncertainty associated with each individual driver. Nonetheless, invasive species are likely to respond in ways that should be qualitatively predictable, and some of these responses will be distinct from those of native counterparts. We used the stages of invasion known as the "invasion pathway" to identify 5 nonexclusive consequences of climate change for invasive species: (1) altered transport and introduction mechanisms, (2) establishment of new invasive species, (3) altered impact of existing invasive species, (4) altered distribution of existing invasive species, and (5) altered effectiveness of control strategies. We then used these consequences to identify testable hypotheses about the responses of invasive species to climate change and provide suggestions for invasive-species management plans. The 5 consequences also emphasize the need for enhanced environmental monitoring and expanded coordination among entities involved in invasive-species management.

Monitoring the Invasion of Spartina alterniflora from 1993 to 2014 with Landsat TM and SPOT 6 Satellite Data in Yueqing Bay, China

PubMed Central

Wang, Anqi; Chen, Jiadai; Jing, Changwei; Ye, Guanqiong; Wu, Jiaping; Huang, Zhixing; Zhou, Chaosheng

2015-01-01

The exotic plant Spartina alterniflora was introduced to Yueqing Bay more than 20 years ago for tidal land reclamation and as a defense against typhoons, but it has rapidly expanded and caused enormous ecological consequences. Mapping the spread and distribution of S. alterniflora is the first step toward understanding the factors that determine the population expansion patterns. Remote sensing is a promising tool to monitor the expansion of S. alterniflora. Twelve Landsat TM images and Support Vector Machine (SVM) were used to delineate the invasion of S. alterniflora from 1993 to 2009, and SPOT 6 images and Object-Based Image Analysis (OBIA) were used to map the distribution of S. alterniflora in 2014. In situ data and Unmanned Aerial Vehicle (UAV) images were used as supplementary data. S. alterniflora spread rapidly in Yueqing Bay over the past 21 years. Between 1993 and 2009, the area of S. alterniflora increased by 608 times (from 4 to 2432 ha). The rapid expansion of S. alterniflora covered almost all of the bare mudflats around the mangrove forests and the cultivated mudflats. However, from 2009 to 2014, the rate of expansion of S. alterniflora began to slow down in Yueqing Bay, and the total area of S. alterniflora in Yantian decreased by 275 ha. These phenomena can be explained by the landscape changes and ecological niches. Through the expansion of S. alterniflora, it was found that the ecological significance and environmental impact of S. alterniflora was different in different regions in Yueqing Bay. The conservation plans for Yueqing Bay should consider both the positive and negative effects of S. alterniflora, and the governmental policy should be based on the different circumstances of the regions. PMID:26263172

Monitoring the Invasion of Spartina alterniflora from 1993 to 2014 with Landsat TM and SPOT 6 Satellite Data in Yueqing Bay, China.

PubMed

Wang, Anqi; Chen, Jiadai; Jing, Changwei; Ye, Guanqiong; Wu, Jiaping; Huang, Zhixing; Zhou, Chaosheng

2015-01-01

The exotic plant Spartina alterniflora was introduced to Yueqing Bay more than 20 years ago for tidal land reclamation and as a defense against typhoons, but it has rapidly expanded and caused enormous ecological consequences. Mapping the spread and distribution of S. alterniflora is the first step toward understanding the factors that determine the population expansion patterns. Remote sensing is a promising tool to monitor the expansion of S. alterniflora. Twelve Landsat TM images and Support Vector Machine (SVM) were used to delineate the invasion of S. alterniflora from 1993 to 2009, and SPOT 6 images and Object-Based Image Analysis (OBIA) were used to map the distribution of S. alterniflora in 2014. In situ data and Unmanned Aerial Vehicle (UAV) images were used as supplementary data. S. alterniflora spread rapidly in Yueqing Bay over the past 21 years. Between 1993 and 2009, the area of S. alterniflora increased by 608 times (from 4 to 2432 ha). The rapid expansion of S. alterniflora covered almost all of the bare mudflats around the mangrove forests and the cultivated mudflats. However, from 2009 to 2014, the rate of expansion of S. alterniflora began to slow down in Yueqing Bay, and the total area of S. alterniflora in Yantian decreased by 275 ha. These phenomena can be explained by the landscape changes and ecological niches. Through the expansion of S. alterniflora, it was found that the ecological significance and environmental impact of S. alterniflora was different in different regions in Yueqing Bay. The conservation plans for Yueqing Bay should consider both the positive and negative effects of S. alterniflora, and the governmental policy should be based on the different circumstances of the regions.

Effectiveness of the aquatic halophyte Sarcocornia perennis spp. perennis as a biotool for ecological restoration of metal-contaminated salt marshes

USDA-ARS?s Scientific Manuscript database

Ecological restoration and creation of salt marshes is needed to compensate for their degradation and loss, but little is known about halophytes as plant biotools in restoration projects. Restoration plantings of halophytes have been established following eradication of invasive populations of the e...

Integrated Inquiry.

ERIC Educational Resources Information Center

Trautmann, Nancy M.; Carlsen, William S.; Krasny, Marianne E.; Cunningham, Christine M.

2000-01-01

Introduces the Environmental Inquiry (EI) program which focuses on five topics: watershed dynamics, environmental toxicology, ecology of invasive species, biodegradations, and urban ecosystem modeling. (YDS)

A conservation planning tool for Greater Sage-grouse using indices of species distribution, resilience, and resistance.

PubMed

Ricca, Mark A; Coates, Peter S; Gustafson, K Benjamin; Brussee, Brianne E; Chambers, Jeanne C; Espinosa, Shawn P; Gardner, Scott C; Lisius, Sherri; Ziegler, Pilar; Delehanty, David J; Casazza, Michael L

2018-06-01

Managers require quantitative yet tractable tools that identify areas for restoration yielding effective benefits for targeted wildlife species and the ecosystems they inhabit. As a contemporary example of high national significance for conservation, the persistence of Greater Sage-grouse (Centrocercus urophasianus) in the Great Basin is compromised by strongly interacting stressors of conifer expansion, annual grass invasion, and more frequent wildfires occurring in sagebrush ecosystems. Associated restoration treatments to a sagebrush-dominated state are often costly and may yield relatively little ecological benefit to sage-grouse if implemented without estimating how Sage-grouse may respond to treatments, or do not consider underlying processes influencing sagebrush ecosystem resilience to disturbance and resistance to invasive species. Here, we describe example applications of a spatially explicit conservation planning tool (CPT) to inform prioritization of: (1) removal of conifers (i.e., pinyon-juniper); and (2) wildfire restoration aimed at improving habitat conditions for the Bi-State Distinct Population Segment of Sage-grouse along the California-Nevada state line. The CPT measures ecological benefits to sage-grouse for a given management action through a composite index comprised of resource selection functions and estimates of abundance and space use. For pinyon-juniper removal, we simulated changes in land-cover composition following the removal of sparse trees with intact understories, and ranked treatments on the basis of changes in ecological benefits per dollar-unit of cost. For wildfire restoration, we formulated a conditional model to simulate scenarios for land cover changes (e.g., sagebrush to annual grass) given estimated fire severity and underlying ecosystem processes influencing resilience to disturbance and resistance to invasion by annual grasses. For both applications, we compared CPT rankings to land cover changes along with sagebrush resistance and resilience metrics. Model results demonstrated how the CPT can be an important step in identifying management projects that yield the highest quantifiable benefit to Sage-grouse while avoiding costly misallocation of resources, and highlight the importance of considering changes in sage-grouse ecological response and factors influencing sagebrush ecosystem resilience to disturbance and resistance to invasion. This unique framework can be adopted to help inform other management questions aimed at improving habitat for other species across sagebrush and other ecosystems. © 2018 The Authors. Ecological Applications published by Wiley Periodicals, Inc. on behalf of Ecological Society of America.

Is rangeland agriculture sustainable?

PubMed

Heitschmidt, R K; Vermeire, L T; Grings, E E

2004-01-01

The objective of this paper is to examine the sustainability of rangeland agriculture (i.e., managed grazing) on a world-wide basis, with a focus on North America. Sustainability is addressed on three fronts: 1) ecological, 2) economic, and 3) social acceptance. Based on previous and on-going research, we suggest that employment of science-based rangeland grazing management strategies and tactics can ensure ecological sustainability. The formidable challenge in employing such technology centers around the need to balance efficiency of solar energy capture and subsequent harvest efficiencies across an array of highly spatially and temporally variable vegetation growing conditions using animals that graze selectively. Failure to meet this fundamental challenge often accelerates rangeland desertification processes, and in some instances, enhances rate and extent of the invasion of noxious weeds. We also suggest that the fundamental reason that ecologically sound grazing management technologies are often not employed in the management of grazed ecological systems is because social values drive management decisions more so than ecological science issues. This is true in both well-developed societies with substantial economic resources and in less-developed societies with few economic resources. However, the social issues driving management are often entirely different, ranging from multiple-use issues in developed countries to human day-to-day survival issues in poorly developed countries. We conclude that the long-term sustainability of rangeland agriculture in 1) developed societies depends on the ability of rangeland agriculturalists to continually respond in a dynamic, positive, proactive manner to ever-changing social values and 2) less-developed societies on their ability to address the ecological and social consequences arising from unsustainable human populations before the adoption of science-based sustainable rangeland management technologies.

Trait-based approaches in the analysis of stream fish communities

USGS Publications Warehouse

Frimpong, Emmanuel; Angermeier, Paul

2010-01-01

Species traits are used to study the functional organization of fish communities for a range of reasons, from simply reducing data dimensionality to providing mechanistic explanations for observed variation in communities. Ecological and life history traits have been used to understand the basic ecology of fishes and predict (1) species and community responses to habitat and climate alteration, and (2) species extinction, species invasion, and community homogenization. Many approaches in this arena have been developed during the past three decades, but they often have not been integrated with related ecological concepts or subdisciplines, which has led to confusion in terminology. We review 102 studies of species traits and then summarize patterns in traits being used and questions being addressed with trait-based approaches. Overall, studies of fish–habitat relationships that apply habitat templates and hierarchical filters dominate our sample; the most frequently used traits are related to feeding. We define and show the relationships among key terms such as fundamental and realized niches; functional traits, performance, and fitness; tactic, trait-state, syndromes, and strategies; and guilds and functional groups. We propose accelerating research to (1) quantify trait plasticity, (2) identify traits useful for testing ecological hypotheses, (3) model habitat and biotic interactions in communities while explicitly accounting for phylogenetic relationships, (4) explore how traits control community assembly, and (5) document the importance of traits in fish– community responses to anthropogenic change and in delivering ecosystem services. Further synthesis of these topics is still needed to develop concepts, models, and principles that can unify the disparate approaches taken in trait-based analysis of fish communities, link fish community ecology to general community ecology, and inform sustainable management of ecosystems.

Historical contingency and ecological determinism interact to prime speciation in sticklebacks, Gasterosteus.

PubMed Central

Taylor, E B; McPhail, J D

2000-01-01

Historical contingency and determinism are often cast as opposing paradigms under which evolutionary diversification operates. It may be, however, that both factors act together to promote evolutionary divergence, although there are few examples of such interaction in nature. We tested phylogenetic predictions of an explicit historical model of divergence (double invasions of freshwater by marine ancestors) in sympatric species of three-spined sticklebacks (Gasterosteus aculeatus) where determinism has been implicated as an important factor driving evolutionary novelty. Microsatellite DNA variation at six loci revealed relatively low genetic variation in freshwater populations, supporting the hypothesis that they were derived by colonization of freshwater by more diverse marine ancestors. Phylogenetic and genetic distance analyses suggested that pairs of sympatric species have evolved multiple times, further implicating determinism as a factor in speciation. Our data also supported predictions based on the hypothesis that the evolution of sympatric species was contingent upon 'double invasions' of postglacial lakes by ancestral marine sticklebacks. Sympatric sticklebacks, therefore, provide an example of adaptive radiation by determinism contingent upon historical conditions promoting unique ecological interactions, and illustrate how contingency and determinism may interact to generate geographical variation in species diversity PMID:11133026

The Use of an Invasive Species Habitat by a Small Folivorous Primate: Implications for Lemur Conservation in Madagascar.

PubMed

Eppley, Timothy M; Donati, Giuseppe; Ramanamanjato, Jean-Baptiste; Randriatafika, Faly; Andriamandimbiarisoa, Laza N; Rabehevitra, David; Ravelomanantsoa, Robertin; Ganzhorn, Jörg U

2015-01-01

The lemurs of Madagascar are among the most threatened mammalian taxa in the world, with habitat loss due to shifting cultivation and timber harvest heavily contributing to their precarious state. Deforestation often leads to fragmentation, resulting in mixed-habitat matrices throughout a landscape where disturbed areas are prone to invasion by exotic plants. Our study site, the Mandena littoral forest (southeast Madagascar), is a matrix of littoral forest, littoral swamp, and Melaleuca swamp habitats. Here, Melaleuca quinquenervia has invaded the wetland ecosystem, creating a mono-dominant habitat that currently provides the only potential habitat corridor between forest fragments. We sought to understand the role of this invasive Melaleuca swamp on the behavioral ecology of a threatened, small-bodied folivore, the southern bamboo lemur (Hapalemur meridionalis). We collected botanical and behavioral data on four groups of H. meridionalis between January and December 2013. Our results confirm Melaleuca swamp as an important part of their home range: while lemurs seasonally limited activities to certain habitats, all groups were capable of utilizing this invasive habitat for feeding and resting. Furthermore, the fact that Hapalemur use an invasive plant species as a dispersal corridor increases our knowledge of their ecological flexibility, and may be useful in the conservation management of remaining threatened populations.

The Use of an Invasive Species Habitat by a Small Folivorous Primate: Implications for Lemur Conservation in Madagascar

PubMed Central

Eppley, Timothy M.; Donati, Giuseppe; Ramanamanjato, Jean-Baptiste; Randriatafika, Faly; Andriamandimbiarisoa, Laza N.; Rabehevitra, David; Ravelomanantsoa, Robertin; Ganzhorn, Jörg U.

2015-01-01

The lemurs of Madagascar are among the most threatened mammalian taxa in the world, with habitat loss due to shifting cultivation and timber harvest heavily contributing to their precarious state. Deforestation often leads to fragmentation, resulting in mixed-habitat matrices throughout a landscape where disturbed areas are prone to invasion by exotic plants. Our study site, the Mandena littoral forest (southeast Madagascar), is a matrix of littoral forest, littoral swamp, and Melaleuca swamp habitats. Here, Melaleuca quinquenervia has invaded the wetland ecosystem, creating a mono-dominant habitat that currently provides the only potential habitat corridor between forest fragments. We sought to understand the role of this invasive Melaleuca swamp on the behavioral ecology of a threatened, small-bodied folivore, the southern bamboo lemur (Hapalemur meridionalis). We collected botanical and behavioral data on four groups of H. meridionalis between January and December 2013. Our results confirm Melaleuca swamp as an important part of their home range: while lemurs seasonally limited activities to certain habitats, all groups were capable of utilizing this invasive habitat for feeding and resting. Furthermore, the fact that Hapalemur use an invasive plant species as a dispersal corridor increases our knowledge of their ecological flexibility, and may be useful in the conservation management of remaining threatened populations. PMID:26536667

Survey of Revegetated Areas on the Fitzner/Eberhardt Arid Lands Ecology Reserve: Status and Initial Monitoring Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Downs, Janelle L.; Link, Steven O.; Rozeboom, Latricia L.

During 2010, the U.S. Department of Energy (DOE), Richland Operations Office removed a number of facilities and debris from the Fitzner/Eberhardt Arid Lands Ecology Reserve (ALE), which is part of the Hanford Reach National Monument (HRNM). Revegetation of disturbed sites is necessary to stabilize the soil, reduce invasion of these areas by exotic weeds, and to accelerate re-establishment of native plant communities. Seven revegetation units were identified on ALE based on soils and potential native plant communities at the site. Native seed mixes and plant material were identified for each area based on the desired plant community. Revegetation of locationsmore » affected by decommissioning of buildings and debris removal was undertaken during the winter and early spring of 2010 and 2011, respectively. This report describes both the details of planting and seeding for each of the units, describes the sampling design for monitoring, and summarizes the data collected during the first year of monitoring. In general, the revegetation efforts were successful in establishing native bunchgrasses and shrubs on most of the sites within the 7 revegetation units. Invasion of the revegetation areas by exotic annual species was minimal for most sites, but was above initial criteria in 3 areas: the Hodges Well subunit of Unit 2, and Units 6 and 7.« less

Invasive Plants Field and Reference Guide: An Ecological Perspective of Plant Invaders of Forests and Woodlands

Treesearch

Cynthia D. Huebner; Cassandra Olson; Heather C. Smith; Heather C. Smith

2005-01-01

There are many field guides available about invasive plants and their identification. The purpose of this particular field guide is to give a scientific synthesis of what is known about the behavior of such species in managed, disturbed, and pristine forested systems in addition to key information for accurate identification.

Alaska biological control program directed at amber-marked birch leaf miner.

Treesearch

J.E. Lundquist; K.F. Zogas; C.L. Snyder; B.K. Schulz

2008-01-01

Nonnative invasive insects are having major impacts on the economics and ecology of forests nationwide. Until recently, Alaska was fortunately mostly free of these pests. Because of the remoteness of much of Alaska's native forests, an invasive pest infestation would be extremely difficult to control. Global markets, global climate change, and the ever-increasing...

The ecology of garlic mustard in eastern hardwood forests

Treesearch

Brian C. McCarthy

2003-01-01

Upwards of 25% of the plant species in many eastern floras have been introduced. Many of these species have become invasive. Many of the worst invasives are native to Eurasia and were brought to the U.S. either intentionally for forage, fiber production, erosion control, ornamentals, or unintentionally via crop seed contaminant, transportation, or nursery stock.

Invasion of an exotic forb impacts reproductive success and site fidelity of a migratory songbird

Treesearch

Yvette Katina Ortega; Kevin Scot McKelvey; Diana Lee Six

2006-01-01

Although exotic plant invasions threaten natural systems worldwide, we know little about the specific ecological impacts of invaders, including the magnitude of effects and underlying mechanisms. Exotic plants are likely to impact higher trophic levels when they overrun native plant communities, affecting habitat quality for breeding songbirds by altering food...

Effects of biological control agents and exotic plant invasion on deer mouse populations

Treesearch

Yvette K. Ortega; Dean E. Pearson; Kevin S. McKelvey

2004-01-01

Exotic insects are commonly introduced as biological control agents to reduce densities of invasive exotic plants. Although current biocontrol programs for weeds take precautions to minimize ecological risks, little attention is paid to the potential nontarget effects of introduced food subsidies on native consumers. Previous research demonstrated that two gall flies (...

PATCH-BURN GRAZING AS A TOOL FOR THE ECOLOGICAL MANAGEMENT OF INVASIVE SPECIES AND RESTORATION OF CARBON SEQUESTRATION AND ECOSYSTEM PROCESSES IN WORKING LANDSCAPES

EPA Science Inventory

Short term - The results of the project will increase information on carbon dynamics under working grassland, and provide a low-input dual conservation/production practice that increases perennial cover and net income while reducing herbicide used to control invasive ...

A watershed decision support tool for managing invasive species on Hawai‘i Island, USA

Treesearch

Nicholas A. Povak; Paul F. Hessburg; Christian P. Giardina; Keith M. Reynolds; Chris Heider; Ed Salminen; R. Brion Salter; Richard A. MacKenzie

2017-01-01

Non-native species invasions, growing human populations, and climate change are central ecological concerns in tropical island communities. The combination of these threats have led to losses of native biota, altered hydrological and ecosystem processes, and reduced ecosystem services. These threats pose complex problems to often underfunded management entities. We...

Influence of oak woodland composition and structure on infection by Phytophthora ramorum

Treesearch

Nathan Rank; Hall Cushman; Brian Anacker; David Rizzo; Ross Meentemeyer

2008-01-01

Introduced plant pathogens have major ecological impacts in many parts of the world. While the spread of pathogens can be strongly mediated by the composition and structure of local host plant communities, little is known about effects of plant community structure on invasion dynamics of introduced pathogens. The progress of infection by the invasive pathogen ...

The impact of the invasive brown marmorated stink bug in North America and Europe: history, biology, ecology, and management

USDA-ARS?s Scientific Manuscript database

Brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), is an invasive Pentatomidae introduced to the USA, Canada, and multiple European countries. In 2010, BMSB populations in the mid-Atlantic region USA reached outbreak levels, and subsequent feeding resulted in severe damage to tree fruit a...

Does seeding after wildfires in rangelands reduce erosion or invasive species?

Treesearch

David A. Pyke; Troy A. Wirth; Jan L. Beyers

2013-01-01

Mitigation of ecological damage caused by rangeland wildfires has historically been an issue restricted to the western United States. It has focused on conservation of ecosystem function through reducing soil erosion and spread of invasive plants. Effectiveness of mitigation treatments has been debated recently. We reviewed recent literature to conduct a meta-analysis...

Using multi-date satellite imagery to monitor invasive grass species distribution in post-wildfire landscapes: An iterative, adaptable approach that employs open-source data and software

USGS Publications Warehouse

West, Amanda M.; Evangelista, Paul H.; Jarnevich, Catherine S.; Kumar, Sunil; Swallow, Aaron; Luizza, Matthew; Chignell, Steve

2017-01-01

Among the most pressing concerns of land managers in post-wildfire landscapes are the establishment and spread of invasive species. Land managers need accurate maps of invasive species cover for targeted management post-disturbance that are easily transferable across space and time. In this study, we sought to develop an iterative, replicable methodology based on limited invasive species occurrence data, freely available remotely sensed data, and open source software to predict the distribution of Bromus tectorum (cheatgrass) in a post-wildfire landscape. We developed four species distribution models using eight spectral indices derived from five months of Landsat 8 Operational Land Imager (OLI) data in 2014. These months corresponded to both cheatgrass growing period and time of field data collection in the study area. The four models were improved using an iterative approach in which a threshold for cover was established, and all models had high sensitivity values when tested on an independent dataset. We also quantified the area at highest risk for invasion in future seasons given 2014 distribution, topographic covariates, and seed dispersal limitations. These models demonstrate the effectiveness of using derived multi-date spectral indices as proxies for species occurrence on the landscape, the importance of selecting thresholds for invasive species cover to evaluate ecological risk in species distribution models, and the applicability of Landsat 8 OLI and the Software for Assisted Habitat Modeling for targeted invasive species management.

Using multi-date satellite imagery to monitor invasive grass species distribution in post-wildfire landscapes: An iterative, adaptable approach that employs open-source data and software

NASA Astrophysics Data System (ADS)

West, Amanda M.; Evangelista, Paul H.; Jarnevich, Catherine S.; Kumar, Sunil; Swallow, Aaron; Luizza, Matthew W.; Chignell, Stephen M.

2017-07-01

Among the most pressing concerns of land managers in post-wildfire landscapes are the establishment and spread of invasive species. Land managers need accurate maps of invasive species cover for targeted management post-disturbance that are easily transferable across space and time. In this study, we sought to develop an iterative, replicable methodology based on limited invasive species occurrence data, freely available remotely sensed data, and open source software to predict the distribution of Bromus tectorum (cheatgrass) in a post-wildfire landscape. We developed four species distribution models using eight spectral indices derived from five months of Landsat 8 Operational Land Imager (OLI) data in 2014. These months corresponded to both cheatgrass growing period and time of field data collection in the study area. The four models were improved using an iterative approach in which a threshold for cover was established, and all models had high sensitivity values when tested on an independent dataset. We also quantified the area at highest risk for invasion in future seasons given 2014 distribution, topographic covariates, and seed dispersal limitations. These models demonstrate the effectiveness of using derived multi-date spectral indices as proxies for species occurrence on the landscape, the importance of selecting thresholds for invasive species cover to evaluate ecological risk in species distribution models, and the applicability of Landsat 8 OLI and the Software for Assisted Habitat Modeling for targeted invasive species management.

Freshwater ecosystems and aquatic insects: a paradox in biological invasions.

PubMed

Fenoglio, Stefano; Bonada, Núria; Guareschi, Simone; López-Rodríguez, Manuel J; Millán, Andrés; Tierno de Figueroa, J Manuel

2016-04-01

Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly all trophic niches, there are almost no invasive insects in freshwaters. We present some hypotheses regarding why aquatic insects are not common among aquatic invasive organisms, suggesting that it may be the result of a suite of biological, ecological and anthropogenic factors. Such specific knowledge introduces a paradox in the current scientific discussion on invasive species; therefore, a more in-depth understanding could be an invaluable aid to disentangling how and why biological invasions occur. © 2016 The Author(s).

Environmental Adaptations, Ecological Filtering, and Dispersal Central to Insect Invasions.

PubMed

Renault, David; Laparie, Mathieu; McCauley, Shannon J; Bonte, Dries

2018-01-07

Insect invasions, the establishment and spread of nonnative insects in new regions, can have extensive economic and environmental consequences. Increased global connectivity accelerates rates of introductions, while climate change may decrease the barriers to invader species' spread. We follow an individual-level insect- and arachnid-centered perspective to assess how the process of invasion is influenced by phenotypic heterogeneity associated with dispersal and stress resistance, and their coupling, across the multiple steps of the invasion process. We also provide an overview and synthesis on the importance of environmental filters during the entire invasion process for the facilitation or inhibition of invasive insect population spread. Finally, we highlight important research gaps and the relevance and applicability of ongoing natural range expansions in the context of climate change to gain essential mechanistic insights into insect invasions.

An invasive herbivore structures plant competitive dynamics.

PubMed

Wong, Lydia; Grainger, Tess Nahanni; Start, Denon; Gilbert, Benjamin

2017-11-01

Species interactions are central to our understanding of ecological communities, but may change rapidly with the introduction of invasive species. Invasive species can alter species interactions and community dynamics directly by having larger detrimental effects on some species than others, or indirectly by changing the ways in which native species compete among themselves. We tested the direct and indirect effects of an invasive aphid herbivore on a native aphid species and two host milkweed species. The invasive aphid caused a 10-fold decrease in native aphid populations, and a 30% increase in plant mortality (direct effects). The invasive aphid also increased the strength of interspecific competition between the two native plant hosts (indirect effects). By investigating the role that indirect effects play in shaping species interactions in native communities, our study highlights an understudied component of species invasions. © 2017 The Author(s).

New Weapons in the Toad Toolkit: A Review of Methods to Control and Mitigate the Biodiversity Impacts of Invasive Cane Toads (Rhinella Marina).

PubMed

Tingley, Reid; Ward-Fear, Georgia; Schwarzkopf, Lin; Greenlees, Matthew J; Phillips, Benjamin L; Brown, Gregory; Clulow, Simon; Webb, Jonathan; Capon, Robert; Sheppard, Andy; Strive, Tanja; Tizard, Mark; Shine, Richard

2017-06-01

Our best hope of developing innovative methods to combat invasive species is likely to come from the study of high-profile invaders that have attracted intensive research not only into control, but also basic biology. Here we illustrate that point by reviewing current thinking about novel ways to control one of the world’s most well-studied invasions: that of the cane toad in Australia. Recently developed methods for population suppression include more effective traps based on the toad’s acoustic and pheromonal biology. New tools for containing spread include surveillance technologies (e.g., eDNA sampling and automated call detectors), as well as landscape-level barriers that exploit the toad’s vulnerability to desiccation—a strategy that could be significantly enhanced through the introduction of sedentary, range-core genotypes ahead of the invasion front. New methods to reduce the ecological impacts of toads include conditioned taste aversion in free-ranging predators, gene banking, and targeted gene flow. Lastly, recent advances in gene editing and gene drive technology hold the promise of modifying toad phenotypes in ways that may facilitate control or buffer impact. Synergies between these approaches hold great promise for novel and more effective means to combat the toad invasion and its consequent impacts on biodiversity.

Non-native megaherbivores: the case for novel function to manage plant invasions on islands

PubMed Central

Hansen, Dennis M.

2015-01-01

There is a heated debate about whether all non-native species are ‘guilty until proven innocent’, or whether some should be accepted or even welcomed. Further fanning the flames, I here present a case where introductions of carefully vetted, non-native species could provide a net conservation benefit. On many islands, native megaherbivores (flightless birds, tortoises) recently went extinct. Here, rewilding with carefully selected non-native species as ecological replacements is increasingly considered a solution, reinstating a herbivory regime that largely benefits the native flora. Based on these efforts, I suggest that restoration practitioners working on islands without a history of native megaherbivores that are threatened by invasive plants should consider introducing a non-native island megaherbivore, and that large and giant tortoises are ideal candidates. Such tortoises would be equally useful on islands where eradication of invasive mammals has led to increased problems with invasive plants, or on islands that never had introduced mammalian herbivores, but where invasive plants are a problem. My proposal may seem radical, but the reversibility of using giant tortoises means that nothing is lost from trying, and that indeed much is to be gained. As an easily regulated adaptive management tool, it represents an innovative, hypothesis-driven ‘innocent until proven guilty’ approach. PMID:26194166

Consequences of plant invasions on compartmentalization and species’ roles in plant–pollinator networks

PubMed Central

Albrecht, Matthias; Padrón, Benigno; Bartomeus, Ignasi; Traveset, Anna

2014-01-01

Compartmentalization—the organization of ecological interaction networks into subsets of species that do not interact with other subsets (true compartments) or interact more frequently among themselves than with other species (modules)—has been identified as a key property for the functioning, stability and evolution of ecological communities. Invasions by entomophilous invasive plants may profoundly alter the way interaction networks are compartmentalized. We analysed a comprehensive dataset of 40 paired plant–pollinator networks (invaded versus uninvaded) to test this hypothesis. We show that invasive plants have higher generalization levels with respect to their pollinators than natives. The consequences for network topology are that—rather than displacing native species from the network—plant invaders attracting pollinators into invaded modules tend to play new important topological roles (i.e. network hubs, module hubs and connectors) and cause role shifts in native species, creating larger modules that are more connected among each other. While the number of true compartments was lower in invaded compared with uninvaded networks, the effect of invasion on modularity was contingent on the study system. Interestingly, the generalization level of the invasive plants partially explains this pattern, with more generalized invaders contributing to a lower modularity. Our findings indicate that the altered interaction structure of invaded networks makes them more robust against simulated random secondary species extinctions, but more vulnerable when the typically highly connected invasive plants go extinct first. The consequences and pathways by which biological invasions alter the interaction structure of plant–pollinator communities highlighted in this study may have important dynamical and functional implications, for example, by influencing multi-species reciprocal selection regimes and coevolutionary processes. PMID:24943368

Trophic overlap between native and invasive stream crayfish

USGS Publications Warehouse

Magoulick, Daniel D.; Piercey, Glenn L.

2016-01-01

We examined trophic dynamics of a stream food web where invasive Orconectes neglectusappear to be displacing native O. eupunctus in the Spring River drainage of the Ozark Highlands, Missouri and Arkansas, USA. We collected crayfish species and possible food sources seasonally from a site of sympatry on the South Fork Spring River. We determined diet overlap and potential for competition between O. eupunctus and O. neglectus, and investigated seasonal variation using carbon and nitrogen stable isotope analyses and gut content analyses. Gut content analysis showed both species of crayfish consumed mainly detritus during summer and spring, with other prey categories varying by species and season. Stable isotope analysis showed that O. eupunctus and O. neglectus relied on invertebrates as a major energy and nutrient source throughout summer, autumn, and spring, and the two species showed differences in their stable isotope signatures during spring and summer, but not autumn. Given the trophic overlap between O. eupunctus and O. neglectus, there is a potential for the two species to compete for food and to be ecologically redundant. Ecological redundancy can lead to reduced effects on ecosystem function post-invasion, and therefore examining ecological redundancy of potential invaders should be a conservation priority.

Exotic insects in North American forests: ecological systems forever altered

Treesearch

William J. Mattson

1998-01-01

More than 400 species of exotic phytophagous insects have become established on native and introduced woody plants in North America. About 5 percent of these invasives have well-recognized, severe ecological impacts on the trees and ecosystems that they occupy. For the others, very little is known about their influence on natural processes. However, evidence suggests...

Legacy introductions and climatic variation explain spatiotemporal patterns of invasive hybridization in a native trout.

PubMed

Muhlfeld, Clint C; Kovach, Ryan P; Al-Chokhachy, Robert; Amish, Stephen J; Kershner, Jeffrey L; Leary, Robb F; Lowe, Winsor H; Luikart, Gordon; Matson, Phil; Schmetterling, David A; Shepard, Bradley B; Westley, Peter A H; Whited, Diane; Whiteley, Andrew; Allendorf, Fred W

2017-11-01

Hybridization between invasive and native species, a significant threat to worldwide biodiversity, is predicted to increase due to climate-induced expansions of invasive species. Long-term research and monitoring are crucial for understanding the ecological and evolutionary processes that modulate the effects of invasive species. Using a large, multidecade genetics dataset (N = 582 sites, 12,878 individuals) with high-resolution climate predictions and extensive stocking records, we evaluate the spatiotemporal dynamics of hybridization between native cutthroat trout and invasive rainbow trout, the world's most widely introduced invasive fish, across the Northern Rocky Mountains of the United States. Historical effects of stocking and contemporary patterns of climatic variation were strongly related to the spread of hybridization across space and time. The probability of occurrence, extent of, and temporal changes in hybridization increased at sites in close proximity to historical stocking locations with greater rainbow trout propagule pressure, warmer water temperatures, and lower spring precipitation. Although locations with warmer water temperatures were more prone to hybridization, cold sites were not protected from invasion; 58% of hybridized sites had cold mean summer water temperatures (<11°C). Despite cessation of stocking over 40 years ago, hybridization increased over time at half (50%) of the locations with long-term data, the vast majority of which (74%) were initially nonhybridized, emphasizing the chronic, negative impacts of human-mediated hybridization. These results show that effects of climate change on biodiversity must be analyzed in the context of historical human impacts that set ecological and evolutionary trajectories. © 2017 John Wiley & Sons Ltd.

Molecular ecology of zebra mussel invasions.

PubMed

May, Gemma E; Gelembiuk, Gregory W; Panov, Vadim E; Orlova, Marina I; Lee, Carol Eunmi

2006-04-01

The invasion of the zebra mussel, Dreissena polymorpha, into North American waters has resulted in profound ecological disturbances and large monetary losses. This study examined the invasion history and patterns of genetic diversity among endemic and invading populations of zebra mussels using DNA sequences from the mitochondrial cytochrome oxidase I (COI) gene. Patterns of haplotype frequency indicate that all invasive populations of zebra mussels from North America and Europe originated from the Ponto-Caspian Sea region. The distribution of haplotypes was consistent with invasive populations arising from the Black Sea drainage, but could not exclude the possibility of an origin from the Caspian Sea drainage. Similar haplotype frequencies among North American populations of D. polymorpha suggest colonization by a single founding population. There was no evidence of invasive populations arising from tectonic lakes in Turkey, while lakes in Greece and Macedonia contained only Dreissena stankovici. Populations in Turkey might be members of a sibling species complex of D. polymorpha. Ponto-Caspian derived populations of D. polymorpha (theta = 0.0011) and Dreissena bugensis (one haplotype) exhibited low levels of genetic diversity at the COI gene, perhaps as a result of repeated population bottlenecks. In contrast, geographically isolated tectonic lake populations exhibited relatively high levels of genetic diversity (theta = 0.0032 to 0.0134). It is possible that the fluctuating environment of the Ponto-Caspian basin facilitated the colonizing habit of invasive populations of D. polymorpha and D. bugensis. Our findings were concordant with the general trend of destructive freshwater invaders in the Great Lakes arising from the Ponto-Caspian Sea basin.

Legacy introductions and climatic variation explain spatiotemporal patterns of invasive hybridization in a native trout

USGS Publications Warehouse

Muhlfeld, Clint C.; Kovach, Ryan P.; Al-Chokhachy, Robert K.; Amish, Stephen J.; Kershner, Jeffrey L.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Matson, Phil; Schmetterling, David A.; Shepard, Bradley B.; Westley, Peter A. H.; Whited, Diane; Whiteley, Andrew R.; Allendorf, Fred W.

2017-01-01

Hybridization between invasive and native species, a significant threat to worldwide biodiversity, is predicted to increase due to climate-induced expansions of invasive species. Long-term research and monitoring are crucial for understanding the ecological and evolutionary processes that modulate the effects of invasive species. Using a large, multi-decade genetics dataset (N = 582 sites, 12,878 individuals) with high-resolution climate predictions and extensive stocking records, we evaluate the spatiotemporal dynamics of hybridization between native cutthroat trout and invasive rainbow trout, the world’s most widely introduced invasive fish, across the northern Rocky Mountains of the United States. Historical effects of stocking and contemporary patterns of climatic variation were strongly related to the spread of hybridization across space and time. The probability of occurrence, extent of, and temporal changes in hybridization increased at sites in close proximity to historical stocking locations with greater rainbow trout propagule pressure, warmer water temperatures, and lower spring precipitation. Although locations with warmer water temperatures were more prone to hybridization, cold sites were not protected from invasion; 58% of hybridized sites had cold mean summer water temperatures (<11°C). Despite cessation of stocking over 40 years ago, hybridization increased over time at half (50%) of the locations with long-term data, the vast majority of which (74%) were initially non-hybridized, emphasizing the chronic, negative impacts of human-mediated hybridization. These results show that effects of climate change on biodiversity must be analyzed in the context of historical human impacts that set ecological and evolutionary trajectories.

Evolutionary dynamics of tree invasions: complementing the unified framework for biological invasions.

PubMed

Zenni, Rafael Dudeque; Dickie, Ian A; Wingfield, Michael J; Hirsch, Heidi; Crous, Casparus J; Meyerson, Laura A; Burgess, Treena I; Zimmermann, Thalita G; Klock, Metha M; Siemann, Evan; Erfmeier, Alexandra; Aragon, Roxana; Montti, Lia; Le Roux, Johannes J

2016-12-30

Evolutionary processes greatly impact the outcomes of biological invasions. An extensive body of research suggests that invasive populations often undergo phenotypic and ecological divergence from their native sources. Evolution also operates at different and distinct stages during the invasion process. Thus, it is important to incorporate evolutionary change into frameworks of biological invasions because it allows us to conceptualize how these processes may facilitate or hinder invasion success. Here, we review such processes, with an emphasis on tree invasions, and place them in the context of the unified framework for biological invasions. The processes and mechanisms described are pre-introduction evolutionary history, sampling effect, founder effect, genotype-by-environment interactions, admixture, hybridization, polyploidization, rapid evolution, epigenetics, and second-genomes. For the last, we propose that co-evolved symbionts, both beneficial and harmful, which are closely physiologically associated with invasive species, contain critical genetic traits that affect the evolutionary dynamics of biological invasions. By understanding the mechanisms underlying invasion success, researchers will be better equipped to predict, understand, and manage biological invasions. Published by Oxford University Press on behalf of the Annals of Botany Company.

Evolutionary dynamics of tree invasions: complementing the unified framework for biological invasions

PubMed Central

Dickie, Ian A.; Wingfield, Michael J.; Hirsch, Heidi; Crous, Casparus J.; Meyerson, Laura A.; Burgess, Treena I.; Zimmermann, Thalita G.; Klock, Metha M.; Siemann, Evan; Erfmeier, Alexandra; Aragon, Roxana; Montti, Lia; Le Roux, Johannes J.

2017-01-01

Abstract Evolutionary processes greatly impact the outcomes of biological invasions. An extensive body of research suggests that invasive populations often undergo phenotypic and ecological divergence from their native sources. Evolution also operates at different and distinct stages during the invasion process. Thus, it is important to incorporate evolutionary change into frameworks of biological invasions because it allows us to conceptualize how these processes may facilitate or hinder invasion success. Here, we review such processes, with an emphasis on tree invasions, and place them in the context of the unified framework for biological invasions. The processes and mechanisms described are pre-introduction evolutionary history, sampling effect, founder effect, genotype-by-environment interactions, admixture, hybridization, polyploidization, rapid evolution, epigenetics and second-genomes. For the last, we propose that co-evolved symbionts, both beneficial and harmful, which are closely physiologically associated with invasive species, contain critical genetic traits that affect the evolutionary dynamics of biological invasions. By understanding the mechanisms underlying invasion success, researchers will be better equipped to predict, understand and manage biological invasions. PMID:28039118

Invasive Plant Management in the United States National Wildlife Refuge

USGS Publications Warehouse

Lusk, Michael; Ericson, Jenny

2011-01-01

Invasive species pose a significant challenge to the National Wildlife Refuge System and have been identified as the single most important threat to habitat management on refuges. At present, it is estimated that over 2 million acres of refuge lands are invaded by invasive plants. The current and potential costs of controlling invasive plants, as well as monitoring and restoring refuge lands, are significant both financially and ecologically. Budgetary expenditures for invasive species projects in FY 2009 totaled $18.4 million. A number of strategies are used to confront this threat and have resulted in success on a variety of levels. The Refuge System utilizes key partnerships, invasive species strike teams, and a dedicated cadre of volunteers to implement projects that incorporate mechanical, chemical and biological control methods.

Modeling invasion of metastasizing cancer cells to bone marrow utilizing ecological principles.

PubMed

Chen, Kun-Wan; Pienta, Kenneth J

2011-10-03

The invasion of a new species into an established ecosystem can be directly compared to the steps involved in cancer metastasis. Cancer must grow in a primary site, extravasate and survive in the circulation to then intravasate into target organ (invasive species survival in transport). Cancer cells often lay dormant at their metastatic site for a long period of time (lag period for invasive species) before proliferating (invasive spread). Proliferation in the new site has an impact on the target organ microenvironment (ecological impact) and eventually the human host (biosphere impact). Tilman has described mathematical equations for the competition between invasive species in a structured habitat. These equations were adapted to study the invasion of cancer cells into the bone marrow microenvironment as a structured habitat. A large proportion of solid tumor metastases are bone metastases, known to usurp hematopoietic stem cells (HSC) homing pathways to establish footholds in the bone marrow. This required accounting for the fact that this is the natural home of hematopoietic stem cells and that they already occupy this structured space. The adapted Tilman model of invasion dynamics is especially valuable for modeling the lag period or dormancy of cancer cells. The Tilman equations for modeling the invasion of two species into a defined space have been modified to study the invasion of cancer cells into the bone marrow microenvironment. These modified equations allow a more flexible way to model the space competition between the two cell species. The ability to model initial density, metastatic seeding into the bone marrow and growth once the cells are present, and movement of cells out of the bone marrow niche and apoptosis of cells are all aspects of the adapted equations. These equations are currently being applied to clinical data sets for verification and further refinement of the models.

Pythium invasion of plant-based life support systems: biological control and sources

NASA Technical Reports Server (NTRS)

Jenkins, D. G.; Cook, K. L.; Garland, J. L.; Board, K. F.; Sager, J. C. (Principal Investigator)

2000-01-01

Invasion of plant-based life support systems by plant pathogens could cause plant disease and disruption of life support capability. Root rot caused by the fungus, Pythium, was observed during tests of prototype plant growth systems containing wheat at the Kennedy Space Center (KSC). We conducted experiments to determine if the presence of complex microbial communities in the plant root zone (rhizosphere) resisted invasion by the Pythium species isolated from the wheat root. Rhizosphere inocula of different complexity (as assayed by community-level physiological profile: CLPP) were developed using a dilution/extinction approach, followed by growth in hydroponic rhizosphere. Pythium growth on wheat roots and concomitant decreases in plant growth were inversely related to the complexity of the inocula during 20-day experiments in static hydroponic systems. Pythium was found on the seeds of several different wheat cultivars used in controlled environmental studies, but it is unclear if the seed-borne fungal strain(s) were identical to the pathogenic strain recovered from the KSC studies. Attempts to control pathogens and their effects in hydroponic life support systems should include early inoculation with complex microbial communities, which is consistent with ecological theory.

Species' traits help predict small mammal responses to habitat homogenization by an invasive grass.

PubMed

Ceradini, Joseph P; Chalfoun, Anna D

2017-07-01

Invasive plants can negatively affect native species, however, the strength, direction, and shape of responses may vary depending on the type of habitat alteration and the natural history of native species. To prioritize conservation of vulnerable species, it is therefore critical to effectively predict species' responses to invasive plants, which may be facilitated by a framework based on species' traits. We studied the population and community responses of small mammals and changes in habitat heterogeneity across a gradient of cheatgrass (Bromus tectorum) cover, a widespread invasive plant in North America. We live-trapped small mammals over two summers and assessed the effect of cheatgrass on native small mammal abundance, richness, and species-specific and trait-based occupancy, while accounting for detection probability and other key habitat elements. Abundance was only estimated for the most common species, deer mice (Peromyscus maniculatus). All species were pooled for the trait-based occupancy analysis to quantify the ability of small mammal traits (habitat association, mode of locomotion, and diet) to predict responses to cheatgrass invasion. Habitat heterogeneity decreased with cheatgrass cover. Deer mouse abundance increased marginally with cheatgrass. Species richness did not vary with cheatgrass, however, pocket mouse (Perognathus spp.) and harvest mouse (Reithrodontomys spp.) occupancy tended to decrease and increase, respectively, with cheatgrass cover, suggesting a shift in community composition. Cheatgrass had little effect on occupancy for deer mice, 13-lined ground squirrels (Spermophilus tridecemlineatus), and Ord's kangaroo rat (Dipodomys ordii). Species' responses to cheatgrass primarily corresponded with our a priori predictions based on species' traits. The probability of occupancy varied significantly with a species' habitat association but not with diet or mode of locomotion. When considered within the context of a rapid habitat change, such as caused by invasive plants, relevant species' traits may provide a useful framework for predicting species' responses to a variety of habitat disturbances. Understanding which species are likely to be most affected by exotic plant invasion will help facilitate more efficient, targeted management and conservation of native species and habitats. © 2017 by the Ecological Society of America.

Hitting the right target: taxonomic challenges for, and of, plant invasions

PubMed Central

Pyšek, Petr; Hulme, Philip E.; Meyerson, Laura A.; Smith, Gideon F.; Boatwright, James S.; Crouch, Neil R.; Figueiredo, Estrela; Foxcroft, Llewellyn C.; Jarošík, Vojtěch; Richardson, David M.; Suda, Jan; Wilson, John R. U.

2013-01-01

This paper explores how a lack of taxonomic expertise, and by implication a dearth of taxonomic products such as identification tools, has hindered progress in understanding and managing biological invasions. It also explores how the taxonomic endeavour could benefit from studies of invasive species. We review the literature on the current situation in taxonomy with a focus on the challenges of identifying alien plant species and explore how this has affected the study of biological invasions. Biosecurity strategies, legislation dealing with invasive species, quarantine, weed surveillance and monitoring all depend on accurate and rapid identification of non-native taxa. However, such identification can be challenging because the taxonomic skill base in most countries is diffuse and lacks critical mass. Taxonomic resources are essential for the effective management of invasive plants and incorrect identifications can impede ecological studies. On the other hand, biological invasions have provided important tests of basic theories about species concepts. Better integration of classical alpha taxonomy and modern genetic taxonomic approaches will improve the accuracy of species identification and further refine taxonomic classification at the level of populations and genotypes in the field and laboratory. Modern taxonomy therefore needs to integrate both classical and new concepts and approaches. In particular, differing points of view between the proponents of morphological and molecular approaches should be negotiated because a narrow taxonomic perspective is harmful; the rigour of taxonomic decision-making clearly increases if insights from a variety of different complementary disciplines are combined and confronted. Taxonomy plays a critical role in the study of plant invasions and in turn benefits from the insights gained from these studies.

Differential invasion success of salmonids in southern Chile: patterns and hypotheses

USGS Publications Warehouse

Arismendi, Ivan; Penaluna, Brooke E.; Dunham, Jason B.; García de Leaniz, Carlos; Soto, Doris; Fleming, Ian A.; Gomez-Uchidam, Daniel; Gajardo, Gonzalo; Vargas, Pamela V.; León-Muñoz, Jorge

2014-01-01

Biological invasions create complex ecological and societal issues worldwide. Most of the knowledge about invasions comes only from successful invaders, but less is known about which processes determine the differential success of invasions. In this review, we develop a framework to identify the main dimensions driving the success and failure of invaders, including human influences, characteristics of the invader, and biotic interactions. We apply this framework by contrasting hypotheses and available evidence to explain variability in invasion success for 12 salmonids introduced to Chile. The success of Oncorhynchus mykiss and Salmo trutta seems to be influenced by a context-specific combination of their phenotypic plasticity, low ecosystem resistance, and propagule pressure. These well-established invaders may limit the success of subsequently introduced salmonids, with the possible exception of O. tshawytscha, which has a short freshwater residency and limited spatial overlap with trout. Although propagule pressure is high for O. kisutch and S. salar due to their intensive use in aquaculture, their lack of success in Chile may be explained by environmental resistance, including earlier spawning times than in their native ranges, and interactions with previously established and resident Rainbow Trout. Other salmonids have also failed to establish, and they exhibit a suite of ecological traits, environmental resistance, and limited propagule pressure that are variably associated with their lack of success. Collectively, understanding how the various drivers of invasion success interact may explain the differential success of invaders and provide key guidance for managing both positive and negative outcomes associated with their presence.

Pushing the envelope in genetic analysis of species invasion

Treesearch

Samuel A. Cushman

2015-01-01

How a species spreads once introduced into a new environment is a major question in landscape genetics. When the species in question is a potential disease vector, the findings are important not only for fundamental science, but can impact applied science and public health as well. In this issue of Molecular Ecology Medley et al. (2014) study, the invasion...

Effects of an invasive tree on community structure and diversity in a tropical forest in Puerto Rico.

Treesearch

K. A. Brown; F. N. Scatena; J. Gurevitch; NO-VALUE

2006-01-01

We report the effects of an invasive tree (Syzygium jambos, Myrtaceace) on species composition, plant diversity patterns, and forest regeneration in primary and secondary forest in the Luquillo Mountains of northeastern Puerto Rico, including the area in and around the Caribbean National Forest (CNF) and the Luquillo Long Term Ecological Research site (Luquillo LTER)....

Effects of climate on emerald ash borer mortality and the potential for ash survival in North America

Treesearch

Ryan D. DeSantis; W. Keith Moser; Dale D. Gormanson; Marshall G. Bartlett; Bradley Vermunt

2013-01-01

Non-native invasive insects such as the emerald ash borer (Agrilus planipennis Fairmaire; EAB) cause billions of dollars; worth of economic damage and unquantifiable but substantial ecological damage in North America each year. There are methods to mitigate, contain, control, or even eradicate some non-native invasive insects, but so far the spread...

Invasive Plants Field and Reference Guide: An Ecological Perspective of Plant Invaders of Forests and Woodlands

Treesearch

Cynthia Huebner; Cassandra Olson; Heather Smith

2005-01-01

There are many field guides available about invasive plants and their identification. The purpose of this particular field guide is to give a scientific synthesis of what is known about the behavior of such species in managed, disturbed, and pristine forested systems in addition to key information for accurate identifi...

Mapping of the Asian longhorned beetle's time to maturity and risk to invasion at contiguous United States extent

Treesearch

Alexander P. Kappel; R. Talbot Trotter; Melody A. Keena; John Rogan; Christopher A. Williams

2017-01-01

Anoplophora glabripennis, the Asian Longhorned Beetle (ALB), is an invasive species of high economic and ecological relevance given the potential it has to cause tree damage, and sometimes mortality, in the United States. Because this pest is introduced by transport in wood-packing products from Asia, ongoing trade activities pose continuous risk...

Large-Scale Assessment of Invasiveness and Potential for Ecological Impact by Nonnative Tree Species.

Treesearch

Kevin M. Potter; William D. Smith

2012-01-01

Biological invasions represent one of the most significant environmental threats to the maintenance of natural forest ecosystems in North America and elsewhere (Liebhold and others 1995), and have been estimated to cause more than $100 billion annually in damage and control costs (Pimentel and others 2000). However, these costs do not take into account the economic...

Community structure affects annual grass weed invasion during restoration of a shrub-steppe ecosystem

Treesearch

Phil S. Allen; Susan E. Meyer

2014-01-01

Ecological restoration of shrub-steppe communities in the western United States is often hampered by invasion of exotic annual grasses during the process. An important question is how to create restored communities that can better resist reinvasion by these weeds. One hypothesis is that communities comprised of species that are functionally similar to the invader will...

Invasive species overarching priorities to 2029

Treesearch

Kelly Burnett; Susan J. Frankel; Melody Keena; Mee-Sook Kim; Ned B. Klopfenstein; Michael E. Ostry; Carolyn Hull Sieg

2010-01-01

Invasive species are one of the greatest threats to forest, range, aquatic, and urban forest ecosystem health. They contribute to the endangerment of native species and may lead to other severe ecological and financial consequences in our Nation’s wildlands and urban forests. Costs the public pays for damage, losses, and control efforts are estimated at more than $138...

Comparing ecohydrological processes in alien vs. native ranges: perspectives from the endangered shrub Myricaria germanica

NASA Astrophysics Data System (ADS)

Michielon, Bruno; Campagnaro, Thomas; Porté, Annabel; Hoyle, Jo; Picco, Lorenzo; Sitzia, Tommaso

2017-04-01

Comparing the ecology of woody species in their alien and native ranges may provide interesting insights for theoretical ecology, invasion biology, restoration ecology and forestry. The literature which describes the biological evolution of successful plant invaders is rich and increasing. However, no general theories have been developed about the geomorphic settings which may limit or favour the alien woody species expansion along rivers. The aim of this contribution is to explore the research opportunities in the comparison of ecohydrological processes occurring in the alien vs. the native ranges of invasive tree and shrub species along the riverine corridor. We use the endangered shrub Myricaria germanica as an example. Myricaria germanica is an Euro-Asiatic pioneer species that, in the native range, develops along natural rivers, wide and dynamic. These conditions are increasingly limited by anthropogenic constraints in most European rivers. This species has been recently introduced in New Zealand, where it is spreading in some natural rivers of the Canterbury region (South Island). We present the current knowledge about the natural and anthropogenic factors influencing this species in its native range. We compare this information with the current knowledge about the same factors influencing M. germanica invasiveness and invasibility of riparian habitats in New Zealand. We stress the need to identify potential factors which could drive life-traits and growing strategies divergence which may hinder the application to the alien ranges of existing ecohydrological knowledge from native ranges. Moreover, the pattern of expansion of the alien range of species endangered in their native ranges opens new windows for research.

Reduced genetic variation and the success of an invasive species.

PubMed

Tsutsui, N D; Suarez, A V; Holway, D A; Case, T J

2000-05-23

Despite the severe ecological and economic damage caused by introduced species, factors that allow invaders to become successful often remain elusive. Of invasive taxa, ants are among the most widespread and harmful. Highly invasive ants are often unicolonial, forming supercolonies in which workers and queens mix freely among physically separate nests. By reducing costs associated with territoriality, unicolonial species can attain high worker densities, allowing them to achieve interspecific dominance. Here we examine the behavior and population genetics of the invasive Argentine ant (Linepithema humile) in its native and introduced ranges, and we provide a mechanism to explain its success as an invader. Using microsatellite markers, we show that a population bottleneck has reduced the genetic diversity of introduced populations. This loss is associated with reduced intraspecific aggression among spatially separate nests, and leads to the formation of interspecifically dominant supercolonies. In contrast, native populations are more genetically variable and exhibit pronounced intraspecific aggression. Although reductions in genetic diversity are generally considered detrimental, these findings provide an example of how a genetic bottleneck can lead to widespread ecological success. In addition, these results provide insights into the origin and evolution of unicoloniality, which is often considered a challenge to kin selection theory.

Vulnerability of Rehabilitated Agricultural Production Systems to Invasion by Nontarget Plant Species

NASA Astrophysics Data System (ADS)

Baer, Sara G.; Engle, David M.; Knops, Johannes M. H.; Langeland, Kenneth A.; Maxwell, Bruce D.; Menalled, Fabian D.; Symstad, Amy J.

2009-02-01

Vast areas of arable land have been retired from crop production and “rehabilitated” to improved system states through landowner incentive programs in the United States (e.g., Conservation and Wetland Reserve Programs), as well as Europe (i.e., Agri-Environment Schemes). Our review of studies conducted on invasion of rehabilitated agricultural production systems by nontarget species elucidates several factors that may increase the vulnerability of these systems to invasion. These systems often exist in highly fragmented and agriculturally dominated landscapes, where propagule sources of target species for colonization may be limited, and are established under conditions where legacies of past disturbance persist and prevent target species from persisting. Furthermore, rehabilitation approaches often do not include or successfully attain all target species or historical ecological processes (e.g., hydrology, grazing, and/or fire cycles) key to resisting invasion. Uncertainty surrounds ways in which nontarget species may compromise long term goals of improving biodiversity and ecosystem services through rehabilitation efforts on former agricultural production lands. This review demonstrates that more studies are needed on the extent and ecological impacts of nontarget species as related to the goals of rehabilitation efforts to secure current and future environmental benefits arising from this widespread conservation practice.

Challenges in global ballast water management.

PubMed

Endresen, Øyvind; Lee Behrens, Hanna; Brynestad, Sigrid; Bjørn Andersen, Aage; Skjong, Rolf

2004-04-01

Ballast water management is a complex issue raising the challenge of merging international regulations, ship's specific configurations along with ecological conservation. This complexity is illustrated in this paper by considering ballast water volume, discharge frequency, ship safety and operational issues aligned with regional characteristics to address ecological risk for selected routes. A re-estimation of ballast water volumes gives a global annual level of 3500 Mton. Global ballast water volume discharged into open sea originating from ballast water exchange operations is estimated to approximately 2800 Mton. Risk based decision support systems coupled to databases for different ports and invasive species characteristics and distributions can allow for differentiated treatment levels while maintaining low risk levels. On certain routes, the risk is estimated to be unacceptable and some kind of ballast water treatment or management should be applied.

Biology, ecology and management of the invasive parthenium weed (Parthenium hysterophorus L.).

PubMed

Adkins, Steve; Shabbir, Asad

2014-07-01

Parthenium weed (Parthenium hysterophorus L.) is one of the most aggressive invasive weeds, threatening natural ecosystems and agroecosystems in over 30 countries worldwide. Parthenium weed causes losses of crops and pastures, degrading the biodiversity of natural plant communities, causing human and animal health hazards and resulting in serious economic losses to people and their interests in many countries around the globe. Several of its biological and ecological attributes contribute towards its invasiveness. Various management approaches (namely cultural, mechanical, chemical and biological control) have been used to minimise losses caused by this weed, but most of these approaches are ineffective and uneconomical and/or have limitations. Although chemical control using herbicides and biological control utilising exotic insects and pathogens have been found to contribute to the management of the weed, the weed nevertheless remains a significant problem. An integrated management approach is proposed here for the effective management of parthenium weed on a sustainable basis. © 2014 Society of Chemical Industry.

Contrasting introduction scenarios among continents in the worldwide invasion of the banana fungal pathogen Mycosphaerella fijiensis.

PubMed

Robert, S; Ravigne, V; Zapater, M-F; Abadie, C; Carlier, J

2012-03-01

Reconstructing and characterizing introduction routes is a key step towards understanding the ecological and evolutionary factors underlying successful invasions and disease emergence. Here, we aimed to decipher scenarios of introduction and stochastic demographic events associated with the global spread of an emerging disease of bananas caused by the destructive fungal pathogen Mycosphaerella fijiensis. We analysed the worldwide population structure of this fungus using 21 microsatellites and 8 sequence-based markers on 735 individuals from 37 countries. Our analyses designated South-East Asia as the source of the global invasion and supported the location of the centre of origin of M. fijiensis within this area. We confirmed the occurrence of bottlenecks upon introduction into other continents followed by widespread founder events within continents. Furthermore, this study suggested contrasting introduction scenarios of the pathogen between the African and American continents. While potential signatures of admixture resulting from multiple introductions were detected in America, all the African samples examined seem to descend from a single successful founder event. In combination with historical information, our study reveals an original and unprecedented global scenario of invasion for this recently emerging disease caused by a wind-dispersed pathogen. © 2012 Blackwell Publishing Ltd.

Do invasive corals alter coral reef processes? An empirical approach evaluating reef fish trophic interactions.

PubMed

Miranda, Ricardo J; Nunes, José de Anchieta C C; Mariano-Neto, Eduardo; Sippo, James Z; Barros, Francisco

2018-07-01

Understanding how invasive species affect key ecological interactions and ecosystem processes is imperative for the management of invasions. We evaluated the effects of invasive corals (Tubastraea spp.) on fish trophic interactions in an Atlantic coral reef. Remote underwater video cameras were used to examine fish foraging activity (bite rates and food preferences) on invasive cover levels. Using a model selection approach, we found that fish feeding rates declined with increased invasive cover. For Roving Herbivores (RH) and Sessile Invertivores (SI), an abrupt reduction of fish feeding rates corresponded with higher invasive cover, while feeding rates of Territorial Herbivores (TH) and Mobile Invertivores (MI) decreased linearly with cover increase. Additionally, some fish trophic groups, such as RH, SI and Omnivores (OM), had lower densities in reef sections with high invasive cover. These findings demonstrate that invasive corals negatively impact fish-benthic interactions, and could potentially alter existing trophic relationships in reef ecosystems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Integrating spatial modeling, climate change scenarios, invasive species risk, and public perceptions to inform sustainable management in mixed hemlock-hardwood forests in Maine

NASA Astrophysics Data System (ADS)

Dunckel, Kathleen Lois

Introduced invasive pests and climate change are perhaps the most important and persistent catalyst for changes in forest composition. Infestation and outbreak of the hemlock woolly adelgid (HWA, Adelges tsugae) along the eastern coast of the USA, has led to widespread loss of hemlock (Tsuga canadensis (L.) Carr.), and a shift in tree species composition towards hardwood stands. Maine's forest dominated landscape and position at the leading edge of the HWA invasion provides an excellent opportunity to inform sustainable forest management (SFM) practices by using spatially explicit models to predict current tree species distribution, future range shifts, and solicit broad based feedback from Maine residents about forest management goals and preferences. This paper describes an interdisciplinary study of the ecological and social implications of changes in mixed northern hardwood forests due to disturbance. A two stage mapping approach was used where presence/absence of eastern hemlock is predicted with an overall accuracy of 85% and the continuous distribution (% basal area) was predicted with an accuracy of 83%. Given the importance of climate variables in predicting eastern hemlock, forecasts of future range shifts are possible using data generated through climate scenarios. The NASA Earth Exchange (NEX) Downscaled Climate Projections (NEX-DCP30) dataset was used to model future shifts in the geographic range of eastern hemlock throughout the state of Maine. The results clearly describe a significant shift in eastern hemlock range with gains in total geographic area that is suitable habitat. Sustaining forest systems across the landscape requires not only ecological knowledge, but also the integration of multiple socio-economic criteria as well, including data obtained through broad-based public participation approaches. Here, 3000 Maine residents were surveyed and asked how they: (1) value local forests; (2) view forest management goals and threats to forest ecosystems; and (3) evaluate alternative treatment options for the control of invasive species - in this case, HWA. Results suggest that despite Maine's historic dependence on forest products, resident values regarding forests are complex and display agreement with both psycho-spiritual and anthropocentric motivations.

ALL THAT "PHRAG": BRINGING ENGINEERING, WETLAND ECOLOGY, ENVIRONMENTAL SCIENCE, AND LANDSCAPE ECOLOGY TO BEAR ON THE QUESTION OF COMMON REED IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Coastal wetlands are among the most fragmented and disturbed ecosystems and the Great Lakes are no exception. One possible result is the observed increase in the presence and dominance of invasive and other opportunistic plant species, such as the common reed (Phragmites australi...

Feral goats in the Hawaiian Islands: understanding the behavioral ecology of nonnative ungulates with GPS and remote sensing technology

Treesearch

Mark Chynoweth; Creighton M. Litton; Christopher A. Lepczyk; Susan Cordell

2010-01-01

Nonnative feral ungulates have both direct and indirect impacts on native ecosystems. Hawai`i is particularly susceptible to biological invasions, as the islands have evolved in extreme geographic isolation. In this paper we explore the ecological impacts of nonnative feral goats (Capra hircus) in the Hawaiian Islands, including both the current...

Per capita invasion probabilities: an empirical model to predict rates of invasion via ballast water

USGS Publications Warehouse

Reusser, Deborah A.; Lee, Henry; Frazier, Melanie; Ruiz, Gregory M.; Fofonoff, Paul W.; Minton, Mark S.; Miller, A. Whitman

2013-01-01

Ballast water discharges are a major source of species introductions into marine and estuarine ecosystems. To mitigate the introduction of new invaders into these ecosystems, many agencies are proposing standards that establish upper concentration limits for organisms in ballast discharge. Ideally, ballast discharge standards will be biologically defensible and adequately protective of the marine environment. We propose a new technique, the per capita invasion probability (PCIP), for managers to quantitatively evaluate the relative risk of different concentration-based ballast water discharge standards. PCIP represents the likelihood that a single discharged organism will become established as a new nonindigenous species. This value is calculated by dividing the total number of ballast water invaders per year by the total number of organisms discharged from ballast. Analysis was done at the coast-wide scale for the Atlantic, Gulf, and Pacific coasts, as well as the Great Lakes, to reduce uncertainty due to secondary invasions between estuaries on a single coast. The PCIP metric is then used to predict the rate of new ballast-associated invasions given various regulatory scenarios. Depending upon the assumptions used in the risk analysis, this approach predicts that approximately one new species will invade every 10–100 years with the International Maritime Organization (IMO) discharge standard of 50 μm per m3 of ballast. This approach resolves many of the limitations associated with other methods of establishing ecologically sound discharge standards, and it allows policy makers to use risk-based methodologies to establish biologically defensible discharge standards.

Population mitogenomics provides insights into evolutionary history, source of invasions and diversifying selection in the House Crow (Corvus splendens).

PubMed

Krzemińska, Urszula; Morales, Hernán E; Greening, Chris; Nyári, Árpád S; Wilson, Robyn; Song, Beng Kah; Austin, Christopher M; Sunnucks, Paul; Pavlova, Alexandra; Rahman, Sadequr

2018-04-01

The House Crow (Corvus splendens) is a useful study system for investigating the genetic basis of adaptations underpinning successful range expansion. The species originates from the Indian subcontinent, but has successfully spread through a variety of thermal environments across Asia, Africa and Europe. Here, population mitogenomics was used to investigate the colonisation history and to test for signals of molecular selection on the mitochondrial genome. We sequenced the mitogenomes of 89 House Crows spanning four native and five invasive populations. A Bayesian dated phylogeny, based on the 13 mitochondrial protein-coding genes, supports a mid-Pleistocene (~630,000 years ago) divergence between the most distant genetic lineages. Phylogeographic patterns suggest that northern South Asia is the likely centre of origin for the species. Codon-based analyses of selection and assessments of changes in amino acid properties provide evidence of positive selection on the ND2 and ND5 genes against a background of purifying selection across the mitogenome. Protein homology modelling suggests that four amino acid substitutions inferred to be under positive selection may modulate coupling efficiency and proton translocation mediated by OXPHOS complex I. The identified substitutions are found within native House Crow lineages and ecological niche modelling predicts suitable climatic areas for the establishment of crow populations within the invasive range. Mitogenomic patterns in the invasive range of the species are more strongly associated with introduction history than climate. We speculate that invasions of the House Crow have been facilitated by standing genetic variation that accumulated due to diversifying selection within the native range.

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 demonstrate how empirical and theoretical techniques can be combined to understand better the processes and consequences of alien species invasions for native biodiversity. © 2016 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Lianas as invasive species in North America: Chapter 28

USGS Publications Warehouse

Leicht-Young, Stacey A.; Pavlovic, Noel B.

2015-01-01

Liana diversity is typically low in the temperate zones; however, the influx of non-native invasive liana species in North America has increased local diversity at the expense of native habitats and species. Some of the most illustrative studies of invasive lianas in temperate North America compared the biological traits of invasive lianas with native congeners or ecological analogs. The majority of these studies focused on two species, Celastrus orbiculatus (oriental bittersweet) and Lonicera japonica (Japanese honeysuckle). Temperate zone lianas generally have higher photosynthetic rates than other early successional species and their host trees. Invasive lianas are having an increasing impact on the dynamics and trajectories of North American plant communities. They often exhibit superior growth and survival compared to their native counterparts, and in some cases, invasive lianas may directly contribute to the decline of their native correlates.

[Ecological risk assessment of dam construction for terrestrial plant species in middle reach of Lancangjiang River, Southwest China].

PubMed

Li, Xiao-Yan; Dong, Shi-Kui; Liu, Shi-Liang; Peng, Ming-Chun; Li, Jin-Peng; Zhao, Qing-He; Zhang, Zhao-Ling

2012-08-01

Taking the surrounding areas of Xiaowan Reservoir in the middle reach of Lancangjiang River as study area, and based on the vegetation investigation at three sites including electricity transmission area (site 1), electricity-transfer substation and roadsides to the substation (site 2), and emigration area (site 3) in 1997 (before dam construction), another investigation was conducted on the vegetation composition, plant coverage, and dominant species at the same sites in 2010 (after dam construction), aimed to evaluate the ecological risk of the dam construction for the terrestrial plant species in middle reach of Lancangjiang River. There was an obvious difference in the summed dominance ratio of dominant species at the three sites before and after the dam construction. According the types of species (dominant and non-dominant species) and the changes of plant dominance, the ecological risk (ER) for the plant species was categorized into 0 to IV, i.e., no or extremely low ecological risk (0), low ecological risk (I), medium ecological risk (II), high ecological risk (III), and extremely high ecological risk (IV). As affected by the dam construction, the majority of the species were at ER III, and a few species were at ER IV. The percentage of the plant species at ER III and ER IV at site 3 was higher than that at sites 1 and 2. The decrease or loss of native plants and the increase of alien or invasive plants were the major ecological risks caused by the dam construction. Effective protection strategies should be adopted to mitigate the ecological risk of the dam construction for the terrestrial plants at species level.

Modeling the Climate and Hydrological Controls of the Expansion of an Invasive Grass Over Southern Arizona

NASA Astrophysics Data System (ADS)

Mathias, A.; Niu, G.; Zeng, X.

2013-12-01

Climate change has an effect on the resilience of ecosystems and the occurrence of ecological perturbations (e.g. spread of invasive species, wildfires). Changes in vegetation in turn can interrupt regional scale climate patterns and alter the spatial and temporal propagation of ecological disturbances. Understanding the controls of vegetation change are essential for predicting future changes, and for setting conservation and restoration targets. Vegetation change in transition zones between ecological regions is a significant indicator of future shifts in the composition of neighboring plant communities. The Walnut Gulch Experimental Watershed is in a grassland-shrubland transition zone between the Sonoran and Chihuahuan Desert in Southern Arizona. During the past decade, at some sites the cover of the invasive Lehmann lovegrass (Eragrostis lehmanniana) drastically increased and the abundance of native vegetation decreased, causing a major decline in biodiversity. Focusing on a catchment scale (Kendall Site), we used an individual based vegetation model (ECOTONE) and a coupled vegetation-3D surface/subsurface hydrology model (ECOTONE-CATHY) to simulate vegetation change. We set up the models with soil and climatological data (NLDAS and AmeriFlux), incorporated initial conditions of species and biomass distribution and species parameters for the site. Using ECOTONE we tested our hypothesis that a combination of dry years and subsequent wet period caused Lehmann lovegass to have advantage over the natives. In ECOTONE species composition and species distribution of plant communities arise from dynamic interactions of individual plants with species specific traits through intra- and interspecific competition for resources (H2O, nitrogen) and their interaction with the environment (precipitation and temperature). Our results indicate that the competitive advantage of Lehmann lovegrass stems from its ability to withstand dryer conditions during establishment and due to its higher seed survival. We are currently using the coupled ECOTONE-CATHY models to evaluate the role of topography and hydrological processes on the patterns of invasion by Lehmann lovegrass. One hypothesis to be tested is that the redistribution of rainfall over the catchment through overland flow controls the spatial distribution of species and biomass, where wetter soil over lowland areas may buffer the effects of climatic control. All these results will be discussed in our presentation.

Live plant imports: the major pathway for forest insect and pathogen invasions of the US

Treesearch

Andrew M. Liebhold; Eckehard G. Brockerhoff; Lynn J. Garrett; Jennifer L. Parke

2012-01-01

Trade in live plants has been recognized worldwide as an important invasion pathway for non-native plant pests. Such pests can have severe economic and ecological consequences. Nearly 70% of damaging forest insects and pathogens established in the US between 1860 and 2006 most likely entered on imported live plants. The current regulation of plant imports is outdated...

Predicting invasive species impacts: a community module functional response approach reveals context dependencies.

PubMed

Paterson, Rachel A; Dick, Jaimie T A; Pritchard, Daniel W; Ennis, Marilyn; Hatcher, Melanie J; Dunn, Alison M

2015-03-01

Predatory functional responses play integral roles in predator-prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species. Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator-prey interactions and thus the predictive capability of the comparative functional response approach. We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses. Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator. Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator. This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

Four-trophic level food webs reveal the cascading impacts of an invasive plant targeted for biocontrol.

PubMed

López-Núñez, Francisco A; Heleno, Ruben H; Ribeiro, Sérgio; Marchante, Hélia; Marchante, Elizabete

2017-03-01

Biological invasions are a major threat to biodiversity and as such understanding their impacts is a research priority. Ecological networks provide a valuable tool to explore such impacts at the community level, and can be particularly insightful for planning and monitoring biocontrol programmes, including the potential for their seldom evaluated indirect non-target effects. Acacia longifolia is among the worst invasive species in Portugal, and has been recently targeted for biocontrol by a highly specific gall-wasp. Here we use an ambitious replicated network approach to: (1) identify the mechanisms by which direct and indirect impacts of A. longifolia can cascade from plants to higher trophic levels, including gallers, their parasitoids and inquilines; (2) reveal the structure of the interaction networks between plants, gallers, parasitoids and inquilines before the biocontrol; and (3) explore the potential for indirect interactions among gallers, including those established with the biocontrol agent, via apparent competition. Over a 15-month period, we collected 31,737 galls from native plants and identified all emerging insects, quantifying the interactions between 219 plant-, 49 galler-, 65 parasitoid- and 87 inquiline-species-one of the largest ecological networks to date. No galls were found on any of the 16 alien plant species. Invasion by A. longifolia caused an alarming simplification of plant communities, with cascading effects to higher trophic levels, namely: a decline of overall gall biomass, and on the richness, abundance and biomass of galler insects, their parasitoids, and inquilines. Correspondingly, we detected a significant decline in the richness of interactions between plants and galls. The invasion tended to increase overall interaction evenness by promoting the local extinction of the native plants that sustained more gall species. However, highly idiosyncratic responses hindered the detection of further consistent changes in network topology. Predictions of indirect effects of the biocontrol on native gallers via apparent competition ranged from negligible to highly significant. Such scenarios are incredibly hard to predict, but even if there are risks of indirect effects it is critical to weigh them carefully against the consequences of inaction and invasive species spread. © 2016 by the Ecological Society of America.

Regional diversity reverses the negative impacts of an alien predator on local species-poor communities.

PubMed

Loewen, Charlie J G; Vinebrooke, Rolf D

2016-10-01

Species diversity is often an implicit source of biological insurance for communities against the impacts of novel perturbations, such as the introduction of an invasive species. High environmental heterogeneity (e.g., a mountainous gradient) is expected to beget greater regional species diversity and variation in functional traits related to environmental tolerances. Thus, heterogeneous metacommunities are expected to provide more tolerant colonists that buffer stressed local communities in the absence of dispersal limitation. We tested the hypothesis that importation of a regional zooplankton pool assembled from a diverse array of lakes and ponds lessens the impacts of a novel predator on local species-poor alpine communities by increasing response diversity (i.e., diversity of tolerances to environmental change) as mediated by variation in functional traits related to predator evasion. We also tested whether impacts varied with temperature, as warming may modify (e.g., dampen or amplify) invasion effects. An eight-week factorial experiment ([fishless vs. introduced Oncorhynchus mykiss (rainbow trout)] × [ambient temperature vs. heated] × [local vs. local + regional species pool]) was conducted using 32 1,000-L mesocosms. Associations between experimental treatments and species functional traits were tested by R-mode linked to Q-mode (RLQ) and fourth-corner analyses. Although the introduced predator suppressed local species richness and community biomass, colonization by several montane zooplankters reversed these negative effects, resulting in increased species diversity and production. Invasion resistance was unaffected by higher temperatures, which failed to elicit any significance impacts on the community. We discovered that the smaller body sizes of imported species drove functional overcompensation (i.e., increased production) in invaded communities. The observed ecological surprise showed how regionally sourced biodiversity from a highly heterogeneous landscape can offset, and even reverse, the local negative impacts of an invasive species. Further, prey body size was found to be a key species trait mediating the ecological impacts of the aquatic invasive predator. Our study highlights the novel application of a functional approach to understanding the impacts of biological invasions, using species traits that pertain directly to potential responses to exotic species. © 2016 by the Ecological Society of America.

Invasive ants compete with and modify the trophic ecology of hermit crabs on tropical islands.

PubMed

McNatty, Alice; Abbott, Kirsti L; Lester, Philip J

2009-05-01

Invasive species can dramatically alter trophic interactions. Predation is the predominant trophic interaction generally considered to be responsible for ecological change after invasion. In contrast, how frequently competition from invasive species contributes to the decline of native species remains controversial. Here, we demonstrate how the trophic ecology of the remote atoll nation of Tokelau is changing due to competition between invasive ants (Anoplolepis gracilipes) and native terrestrial hermit crabs (Coenobita spp.) for carrion. A significant negative correlation was observed between A. gracilipes and hermit crab abundance. On islands with A. gracilipes, crabs were generally restricted to the periphery of invaded islands. Very few hermit crabs were found in central areas of these islands where A. gracilipes abundances were highest. Ant exclusion experiments demonstrated that changes in the abundance and distribution of hermit crabs on Tokelau are a result of competition. The ants did not kill the hermit crabs. Rather, when highly abundant, A. gracilipes attacked crabs by spraying acid and drove crabs away from carrion resources. Analysis of naturally occurring N and C isotopes suggests that the ants are effectively lowering the trophic level of crabs. According to delta(15) N values, hermit crabs have a relatively high trophic level on islands where A. gracilipes have not invaded. In contrast, where these ants have invaded we observed a significant decrease in delta(15) N for all crab species. This result concurs with our experiment in suggesting long-term exclusion from carrion resources, driving co-occurring crabs towards a more herbivorous diet. Changes in hermit crab abundance or distribution may have major ramifications for the stability of plant communities. Because A. gracilipes have invaded many tropical islands where the predominant scavengers are hermit crabs, we consider that their competitive effects are likely to be more prominent in structuring communities than predation.

A comparison of six different ballast water treatment systems based on UV radiation, electrochlorination and chlorine dioxide.

PubMed

Stehouwer, Peter Paul; Buma, Anita; Peperzak, Louis

2015-01-01

The spread of aquatic invasive species through ballast water is a major ecological and economical threat. Because of this, the International Maritime Organization (IMO) set limits to the concentrations of organisms allowed in ballast water. To meet these limits, ballast water treatment systems (BWTSs) were developed. The main techniques used for ballast water treatment are ultraviolet (UV) radiation and electrochlorination (EC). In this study, phytoplankton regrowth after treatment was followed for six BWTSs. Natural plankton communities were treated and incubated for 20 days. Growth, photosystem II efficiency and species composition were followed. The three UV systems all showed similar patterns of decrease in phytoplankton concentrations followed by regrowth. The two EC and the chlorine dioxide systems showed comparable results. However, UV- and chlorine-based treatment systems showed significantly different responses. Overall, all BWTSs reduced phytoplankton concentrations to below the IMO limits, which represents a reduced risk of aquatic invasions through ballast water.

[Identification of potentially invasive species of black flies [Diptera: Simuliidae] from Armenia based on an analysis of variability in the mtDNA barcode of the cox1 gene and chromosomal polymorphism].

PubMed

Andrianov, B V; Goryacheva, I I; Vlasov, S V; Gorelova, T V; Harutyunova, M V; Harutyunova, K V; Mayilyan, K R; Zakharov, I A

2015-03-01

Black flies (Diptera, Simuliidae) are well known for their medical, environmental, and veterinary importance. The simuliid fauna of Armenia includes 53 species. A number of dominant species are of ecological importance. Complex analysis, which involved morphometric, cytogenetic, and molecular genetic approaches, was conducted to characterize the species status of black flies inhabiting the territory of Armenia. It was shown that the predominant simuliid species, Simulium paraequinum and Simulium kiritshenkoi, belong to a group of species with minimal variability of the cox1 gene. The recently discovered species, Simulium noellery and Simulium [B.] erythrocephalum, which are new to Armenia, can be considered as potentially invasive, which is supported by the low level of variability of the cox1 gene.

Linking genomics and ecology to investigate the complex evolution of an invasive Drosophila pest.

PubMed

Ometto, Lino; Cestaro, Alessandro; Ramasamy, Sukanya; Grassi, Alberto; Revadi, Santosh; Siozios, Stefanos; Moretto, Marco; Fontana, Paolo; Varotto, Claudio; Pisani, Davide; Dekker, Teun; Wrobel, Nicola; Viola, Roberto; Pertot, Ilaria; Cavalieri, Duccio; Blaxter, Mark; Anfora, Gianfranco; Rota-Stabelli, Omar

2013-01-01

Drosophilid fruit flies have provided science with striking cases of behavioral adaptation and genetic innovation. A recent example is the invasive pest Drosophila suzukii, which, unlike most other Drosophila, lays eggs and feeds on undamaged, ripening fruits. This not only poses a serious threat for fruit cultivation but also offers an interesting model to study evolution of behavioral innovation. We developed genome and transcriptome resources for D. suzukii. Coupling analyses of these data with field observations, we propose a hypothesis of the origin of its peculiar ecology. Using nuclear and mitochondrial phylogenetic analyses, we confirm its Asian origin and reveal a surprising sister relationship between the eugracilis and the melanogaster subgroups. Although the D. suzukii genome is comparable in size and repeat content to other Drosophila species, it has the lowest nucleotide substitution rate among the species analyzed in this study. This finding is compatible with the overwintering diapause of D. suzukii, which results in a reduced number of generations per year compared with its sister species. Genome-scale relaxed clock analyses support a late Miocene origin of D. suzukii, concomitant with paleogeological and climatic conditions that suggest an adaptation to temperate montane forests, a hypothesis confirmed by field trapping. We propose a causal link between the ecological adaptations of D. suzukii in its native habitat and its invasive success in Europe and North America.

Linking Genomics and Ecology to Investigate the Complex Evolution of an Invasive Drosophila Pest

PubMed Central

Ometto, Lino; Cestaro, Alessandro; Ramasamy, Sukanya; Grassi, Alberto; Revadi, Santosh; Siozios, Stefanos; Moretto, Marco; Fontana, Paolo; Varotto, Claudio; Pisani, Davide; Dekker, Teun; Wrobel, Nicola; Viola, Roberto; Pertot, Ilaria; Cavalieri, Duccio; Blaxter, Mark; Anfora, Gianfranco; Rota-Stabelli, Omar

2013-01-01

Drosophilid fruit flies have provided science with striking cases of behavioral adaptation and genetic innovation. A recent example is the invasive pest Drosophila suzukii, which, unlike most other Drosophila, lays eggs and feeds on undamaged, ripening fruits. This not only poses a serious threat for fruit cultivation but also offers an interesting model to study evolution of behavioral innovation. We developed genome and transcriptome resources for D. suzukii. Coupling analyses of these data with field observations, we propose a hypothesis of the origin of its peculiar ecology. Using nuclear and mitochondrial phylogenetic analyses, we confirm its Asian origin and reveal a surprising sister relationship between the eugracilis and the melanogaster subgroups. Although the D. suzukii genome is comparable in size and repeat content to other Drosophila species, it has the lowest nucleotide substitution rate among the species analyzed in this study. This finding is compatible with the overwintering diapause of D. suzukii, which results in a reduced number of generations per year compared with its sister species. Genome-scale relaxed clock analyses support a late Miocene origin of D. suzukii, concomitant with paleogeological and climatic conditions that suggest an adaptation to temperate montane forests, a hypothesis confirmed by field trapping. We propose a causal link between the ecological adaptations of D. suzukii in its native habitat and its invasive success in Europe and North America. PMID:23501831

Disease introduction is associated with a phase transition in bighorn sheep demographics

PubMed Central

Manlove, Kezia; Cassirer, E. Frances; Cross, Paul Chafee; Plowright, Raina K.; Hudson, Peter J.

2016-01-01

Ecological theory suggests that pathogens are capable of regulating or limiting host population dynamics, and this relationship has been empirically established in several settings. However, although studies of childhood diseases were integral to the development of disease ecology, few studies show population limitation by a disease affecting juveniles. Here, we present empirical evidence that disease in lambs constrains population growth in bighorn sheep (Ovis canadensis) based on 45 years of population-level and 18 years of individual-level monitoring across 12 populations. While populations generally increased (lambda =1.11) prior to disease introduction, most of these same populations experienced an abrupt change in trajectory at the time of disease invasion, usually followed by stagnant-to-declining growth rates (lambda = 0.98) over the next twenty years. Disease-induced juvenile mortality imposed strong constraints on population growth that were not observed prior to disease introduction, even as adult survival returned to pre-invasion levels. Simulations suggested that models including persistent disease-induced mortality in juveniles qualitatively matched observed population trajectories, whereas models that only incorporated all-age disease events did not. We use these results to argue that pathogen persistence may pose a lasting, but under-recognized, threat to host populations, particularly in cases where clinical disease manifests primarily in juveniles. PMID:27859120

Disease introduction is associated with a phase transition in bighorn sheep demographics

USGS Publications Warehouse

Manlove, Kezia; Cassirer, E. Frances; Cross, Paul C.; Plowright, Raina K.; Hudson, Peter J.

2016-01-01

Ecological theory suggests that pathogens are capable of regulating or limiting host population dynamics, and this relationship has been empirically established in several settings. However, although studies of childhood diseases were integral to the development of disease ecology, few studies show population limitation by a disease affecting juveniles. Here, we present empirical evidence that disease in lambs constrains population growth in bighorn sheep (Ovis canadensis) based on 45 years of population-level and 18 years of individual-level monitoring across 12 populations. While populations generally increased (λ = 1.11) prior to disease introduction, most of these same populations experienced an abrupt change in trajectory at the time of disease invasion, usually followed by stagnant-to-declining growth rates (λ = 0.98) over the next 20 years. Disease-induced juvenile mortality imposed strong constraints on population growth that were not observed prior to disease introduction, even as adult survival returned to pre-invasion levels. Simulations suggested that models including persistent disease-induced mortality in juveniles qualitatively matched observed population trajectories, whereas models that only incorporated all-age disease events did not. We use these results to argue that pathogen persistence may pose a lasting, but under-recognized, threat to host populations, particularly in cases where clinical disease manifests primarily in juveniles.

Rooting Theories of Plant Community Ecology in Microbial Interactions

PubMed Central

Bever, James D.; Dickie, Ian A.; Facelli, Evelina; Facelli, Jose M.; Klironomos, John; Moora, Mari; Rillig, Matthias C.; Stock, William D.; Tibbett, Mark; Zobel, Martin

2010-01-01

Predominant frameworks for understanding plant ecology have an aboveground bias that neglects soil micro-organisms. This is inconsistent with recent work illustrating the importance of soil microbes in terrestrial ecology. Microbial effects have been incorporated into plant community dynamics using ideas of niche modification and plant-soil community feedbacks. Here, we expand and integrate qualitative conceptual models of plant niche and feedback to explore implications of microbial interactions for understanding plant community ecology. At the same time we review the empirical evidence for these processes. We also consider common mycorrhizal networks, and suggest these are best interpreted within the feedback framework. Finally, we apply our integrated model of niche and feedback to understanding plant coexistence, monodominance, and invasion ecology. PMID:20557974

A high-throughput detection method for invasive fruit fly (Diptera: Tephritidae) species based on microfluidic dynamic array.

PubMed

Jiang, Fan; Fu, Wei; Clarke, Anthony R; Schutze, Mark Kurt; Susanto, Agus; Zhu, Shuifang; Li, Zhihong

2016-11-01

Invasive species can be detrimental to a nation's ecology, economy and human health. Rapid and accurate diagnostics are critical to limit the establishment and spread of exotic organisms. The increasing rate of biological invasions relative to the taxonomic expertise available generates a demand for high-throughput, DNA-based diagnostics methods for identification. We designed species-specific qPCR primer and probe combinations for 27 economically important tephritidae species in six genera (Anastrepha, Bactrocera, Carpomya, Ceratitis, Dacus and Rhagoletis) based on 935 COI DNA barcode haplotypes from 181 fruit fly species publically available in BOLD, and then tested the specificity for each primer pair and probe through qPCR of 35 of those species. We then developed a standardization reaction system for detecting the 27 target species based on a microfluidic dynamic array and also applied the method to identify unknown immature samples from port interceptions and field monitoring. This method led to a specific and simultaneous detection for all 27 species in 7.5 h, using only 0.2 μL of reaction system in each reaction chamber. The approach successfully discriminated among species within complexes that had genetic similarities of up to 98.48%, while it also identified all immature samples consistent with the subsequent results of morphological examination of adults which were reared from larvae of cohorts from the same samples. We present an accurate, rapid and high-throughput innovative approach for detecting fruit flies of quarantine concern. This is a new method which has broad potential to be one of international standards for plant quarantine and invasive species detection. © 2016 John Wiley & Sons Ltd.

Exotic annual Bromus invasions: comparisons among species and ecoregions in the western United States

USGS Publications Warehouse

Brooks, Matthew L.; Brown, Cynthia S.; Chambers, Jeanne C.; D'Antonio, Carla M.; Keeley, Jon E.; Belnap, Jayne

2016-01-01

Exotic annual Bromus species are widely recognized for their potential to invade, dominate, and alter the structure and function of ecosystems. In this chapter, we summarize the invasion potential, ecosystem threats, and management strategies for different Bromus species within each of five ecoregions of the western United States. We characterize invasion potential and threats in terms of ecosystem resistance to Bromus invasion and ecosystem resilience to disturbance with an emphasis on the importance of fi re regimes. We also explain how soil temperature and moisture regimes can be linked to patterns of resistance and resilience and provide a conceptual framework that can be used to evaluate the relative potential for invasion and ecological impact of the dominant exotic annual Bromus species in the western United States.

Ecological correlates of the non-indigenous parasitoid assemblage associated with a Hawaiian endemic moth.

PubMed

Kaufman, Leyla V; Wright, Mark G

2011-08-01

Understanding what ecological factors might predispose indigenous habitats to invasion by invasive species is an important aspect of conservation and invasive species management, particularly when biological control is considered for suppression of the invasive species. This study seeks to identify ecological factors that might play a role in determining the structure of the parasitoid assemblage associated with caterpillars of the endemic Hawaiian moth Udea stellata (Crambidae). Parasitoids were reared from field-collected U. stellata larvae at 18 locations. Fourteen environmental variables were measured at each site. Two multivariate analyses, principal component analysis (PCA) and partial redundancy analysis (RDA), were used to analyze the parasitoid assemblage across a range of habitats varying in environmental characteristics. The PCA analysis showed that the occurrence of some species were highly correlated, and associated with less disturbed sites, whereas other species were associated with sites of medium and high levels of disturbance. The RDA analysis showed that only three of the measured environmental variables (U. stellata density, elevation, and level of habitat disturbance) significantly explained variability in the parasitoid assemblage among sites. There was greater parasitoid species richness associated with U. stellata larvae at higher elevation sites with a lower degree of habitat disturbance by exotic vegetation. The purposely introduced parasitoid species were associated with the non-target moth at sites located at higher elevations with low levels of disturbance. Multivariate analysis has the potential to provide valuable insights into the identification of important environmental factors that mediate parasitoid assemblage structure and level of parasitism on a particular target or non-target species, and therefore facilitate identification of suitable target habitats or susceptible non-target habitats.

Classical biological control of an invasive forest pest: a world perspective of the management of Sirex noctilio using the parasitoid Ibalia leucospoides (Hymenoptera: Ibaliidae).

PubMed

Fischbein, D; Corley, J C

2015-02-01

Classical biological control is a key method for managing populations of pests in long-lived crops such as plantation forestry. The execution of biological control programmes in general, as the evaluation of potential natural enemies remains, to a large extent, an empirical endeavour. Thus, characterizing specific cases to determine patterns that may lead to more accurate predictions of success is an important goal of the much applied ecological research. We review the history of introduction, ecology and behaviour of the parasitoid Ibalia leucospoides. The species is a natural enemy of Sirex noctilio, one of the most important pests of pine afforestation worldwide. We use an invasion ecology perspective given the analogy between the main stages involved in classical biological control and the biological invasion processes. We conclude that success in the establishment, a common reason of failure in biocontrol, is not a limiting factor of success by I. leucospoides. A mismatch between the spread capacity of the parasitoid and that of its host could nevertheless affect control at a regional scale. In addition, we suggest that given its known life history traits, this natural enemy may be a better regulator than suppressor of the host population. Moreover, spatial and temporal refuges of the host population that may favour the local persistence of the interaction probably reduce the degree to which S. noctilio population is suppressed by the parasitoid. We emphasize the fact that some of the biological attributes that promote establishment may negatively affect suppression levels achieved. Studies on established non-native pest-parasitoid interactions may contribute to defining selection criteria for classical biological control which may prove especially useful in integrated pest management IPM programmes of invasive forest insects.

Cascade of ecological consequences for West Nile virus transmission when aquatic macrophytes invade stormwater habitats.

PubMed

Mackay, Andrew J; Muturi, Ephantus J; Ward, Michael P; Allan, Brian F

2016-01-01

Artificial aquatic habitats are ubiquitous in anthropogenic landscapes and highly susceptible to colonization by invasive plant species. Recent research into the ecology of infectious diseases indicates that the establishment of invasive plant species can trigger ecological cascades which alter the transmission dynamics of vector-borne pathogens that imperil human health. Here, we examined whether the presence or management of two invasive, emergent plants, cattails (Typha spp.) and phragmites (Phragmites australis), in stormwater dry detention basins (DDBs) alter the local distribution of vectors, avian hosts, or West Nile virus (WNV) transmission risk in an urban residential setting. Mosquitoes and birds were surveyed at 14 DDBs and paired adjacent residential sites. During the study period, emergent vegetation was mowed by site managers in three DDBs. In the absence of vegetation management, the overall abundance and species composition of both adult vectors and avian hosts differed between residential and DDB habitats; however, WNV entomological risk indices were equivalent. Communal bird roosts composed primarily of three species, European Starlings (Sturnus vulgaris), Red-winged Blackbirds (Agelaius phoeniceus), and Common Grackles (Quiscalus quiscula), representing a broad range of WNV reservoir competence, were observed at half (three out of six) of the DDBs containing unmanaged stands of phragmites; however, their presence was associated with a lower seasonal increase in vector infection rate. Conversely, mowing of emergent vegetation resulted in a significant and sustained increase in the abundance of WNV-infected vectors in DDBs and the increase in risk extended to adjacent residential sites. These findings indicate that management of invasive plants in DDBs during the growing season can increase, while presence of communal bird roosts can decrease, WNV transmission risk.

Anthropogenic disturbance can determine the magnitude of opportunistic species responses on marine urban infrastructures.

PubMed

Airoldi, Laura; Bulleri, Fabio

2011-01-01

Coastal landscapes are being transformed as a consequence of the increasing demand for infrastructures to sustain residential, commercial and tourist activities. Thus, intertidal and shallow marine habitats are largely being replaced by a variety of artificial substrata (e.g. breakwaters, seawalls, jetties). Understanding the ecological functioning of these artificial habitats is key to planning their design and management, in order to minimise their impacts and to improve their potential to contribute to marine biodiversity and ecosystem functioning. Nonetheless, little effort has been made to assess the role of human disturbances in shaping the structure of assemblages on marine artificial infrastructures. We tested the hypothesis that some negative impacts associated with the expansion of opportunistic and invasive species on urban infrastructures can be related to the severe human disturbances that are typical of these environments, such as those from maintenance and renovation works. Maintenance caused a marked decrease in the cover of dominant space occupiers, such as mussels and oysters, and a significant enhancement of opportunistic and invasive forms, such as biofilm and macroalgae. These effects were particularly pronounced on sheltered substrata compared to exposed substrata. Experimental application of the disturbance in winter reduced the magnitude of the impacts compared to application in spring or summer. We use these results to identify possible management strategies to inform the improvement of the ecological value of artificial marine infrastructures. We demonstrate that some of the impacts of globally expanding marine urban infrastructures, such as those related to the spread of opportunistic, and invasive species could be mitigated through ecologically-driven planning and management of long-term maintenance of these structures. Impact mitigation is a possible outcome of policies that consider the ecological features of built infrastructures and the fundamental value of controlling biodiversity in marine urban systems.

Predator control promotes invasive dominated ecological states.

PubMed

Wallach, Arian D; Johnson, Christopher N; Ritchie, Euan G; O'Neill, Adam J

2010-08-01

Invasive species are regarded as one of the top five drivers of the global extinction crisis. In response, extreme measures have been applied in an attempt to control or eradicate invasives, with little success overall. We tested the idea that state shifts to invasive dominance are symptomatic of losses in ecosystem resilience, due to the suppression of apex predators. This concept was investigated in Australia where the high rate of mammalian extinctions is largely attributed to the destructive influence of invasive species. Intensive pest control is widely applied across the continent, simultaneously eliminating Australia's apex predator, the dingo (Canis lupus dingo). We show that predator management accounts for shifts between two main ecosystem states. Lethal control fractures dingo social structure and leads to bottom-up driven increases in invasive mesopredators and herbivores. Where control is relaxed, dingoes re-establish top-down regulation of ecosystems, allowing for the recovery of biodiversity and productivity.

Nonnative forest insects and pathogens in the United States: impacts and policy options

Treesearch

Gary M. Lovett; Marissa Weiss; Andrew M. Liebhold; Tom Holmes; Brian Leung; Kathy-Fallon Lambert; David A. Orwig; Faith T. Campbell; Jonathan Rosenthal; Deborah G. McCullough; Radka Wildova; Matthew P. Ayres; Charles D. Canham; David R. Foster; Shannon L. LaDeau; Troy Weldy

2016-01-01

We review and synthesize information on invasions of nonnative forest insects and diseases in the United States, including their ecological and economic impacts, pathways of arrival, distribution within the United States, and policy options for reducing future invasions. Nonnative insects have accumulated in United States forests at a rate of ~2.5 per yr over the last...

Differences in ecological structure, function, and native species abundance between native and invaded Hawaiian streams

Treesearch

Tara Holitzki; Richard A. MacKenzie; Tracy N. Wiegner; Karla J. McDermid

2013-01-01

Poeciliids, one of the most invasive species worldwide, are found on almost every continent and have been identified as an ‘‘invasive species of concern’’ in the United States, New Zealand, and Australia. Despite their global prevalence, few studies have quantified their impacts on tropical stream ecosystem structure, function, and biodiversity. Utilizing Hawaiian...

The Mountain Invasion Research Network (MIREN): Linking Local and Global Scales for Addressing an Ecological Consequence of Global Change

Treesearch

Christoph Kueffer; Curtis Daehler; Hansjörg Dietz; Keith McDougall; Catherine Parks; Aníbal Pauchard; Lisa Rew

2014-01-01

Many modern environmental problems span vastly different spatial scales, from the management of local ecosystems to understanding globally interconnected processes, and addressing them through international policy. MIREN tackles one such “glocal” (global/local) environmental problem – plant invasions in mountains – through a transdisciplinary, multi-scale learning...

Ecology of West Nile Virus in North America

PubMed Central

Reisen, William K.

2013-01-01

The introduction, dispersal and establishment of West Nile virus in North America were reviewed, focusing on factors that may have enhanced receptivity and enabled the invasion process. The overwintering persistence of this tropical virus within temperate latitudes was unexpected, but was key in the transition from invasion to endemic establishment. The cascade of temporal events allowing sporadic amplification to outbreak levels was discussed within a future perspective. PMID:24008376

Ecology and genetics affect relative invasion success of two Echium species in southern Australia

PubMed Central

Zhu, Xiaocheng; Weston, Paul A.; Skoneczny, Dominik; Gopurenko, David; Meyer, Lucie; Lepschi, Brendan J.; Callaway, Ragan M.; Gurr, Geoff M.; Weston, Leslie A.

2017-01-01

Echium plantagineum and E. vulgare are congeneric exotics first introduced to Australia in the early 1800 s. There, E. plantagineum is now highly invasive, whereas E. vulgare has a limited distribution. Studies were conducted to evaluate distribution, ecology, genetics and secondary chemistry to shed light on factors associated with their respective invasive success. When sampled across geographically diverse locales, E. plantagineum was widespread and exhibited a small genome size (1 C = 0.34 pg), an annual life cycle, and greater genetic diversity as assessed by DNA sequence analysis. It was found frequently in areas with temperature extremes and low rainfall. In contrast, E. vulgare exhibited a larger genome size (1 C = 0.43 pg), a perennial lifecycle, less chloroplast genetic diversity, and occurred in areas with lower temperatures and higher rainfall. Twelve chloroplast haplotypes of E. plantagineum were evident and incidence aligned well with reported historical introduction events. In contrast, E. vulgare exhibited two haplotypes and was found only sporadically at higher elevations. Echium plantagineum possessed significantly higher levels of numerous pyrrolizidine alkaloids involved in plant defence. We conclude that elevated genetic diversity, tolerance to environmental stress and capacity for producing defensive secondary metabolites have contributed to the successful invasion of E. plantagineum in Australia. PMID:28211478

Integrating diverse scientific and practitioner knowledge in ecological risk analysis: a case study of biodiversity risk assessment in South Africa.

PubMed

Dana, G V; Kapuscinski, A R; Donaldson, J S

2012-05-15

Ecological risk analysis (ERA) is a structured evaluation of threats to species, natural communities, and ecosystem processes from pollutants and toxicants and more complicated living stressors such as invasive species, genetically modified organisms, and biological control agents. Such analyses are typically conducted by a narrowly-focused group of scientific experts using technical information. We evaluate whether the inclusion of more diverse experts and practitioners in ERA improved the ecological knowledge base about South African biodiversity and the potential impacts of genetically modified (GM) crops. We conducted two participatory ERA workshops in South Africa, analyzing potential impacts of GM maize on biodiversity. The first workshop involved only four biological scientists, who were joined by 18 diverse scientists and practitioners in the second, and we compared the ERA process and results between the two using descriptive statistics and semi-structured interview responses. The addition of diverse experts and practitioners led to a more comprehensive understanding of biological composition of the agro-ecosystem and a more ecologically relevant set of hazards, but impeded hazard prioritization and the generation of precise risk assessment values. Results suggest that diverse participation can improve the scoping or problem formulation of the ERA, by generating an ecologically robust set of information on which to base the subsequent, more technical risk assessment. The participatory ERA process also increased the transparency of the ERA by exposing the logic and rationale for decisions made at each step. Copyright © 2011 Elsevier Ltd. All rights reserved.

Improving Conceptual Understanding and Representation Skills Through Excel-Based Modeling

NASA Astrophysics Data System (ADS)

Malone, Kathy L.; Schunn, Christian D.; Schuchardt, Anita M.

2018-02-01

The National Research Council framework for science education and the Next Generation Science Standards have developed a need for additional research and development of curricula that is both technologically model-based and includes engineering practices. This is especially the case for biology education. This paper describes a quasi-experimental design study to test the effectiveness of a model-based curriculum focused on the concepts of natural selection and population ecology that makes use of Excel modeling tools (Modeling Instruction in Biology with Excel, MBI-E). The curriculum revolves around the bio-engineering practice of controlling an invasive species. The study takes place in the Midwest within ten high schools teaching a regular-level introductory biology class. A post-test was designed that targeted a number of common misconceptions in both concept areas as well as representational usage. The results of a post-test demonstrate that the MBI-E students significantly outperformed the traditional classes in both natural selection and population ecology concepts, thus overcoming a number of misconceptions. In addition, implementing students made use of more multiple representations as well as demonstrating greater fascination for science.

Interference competition and invasion: spatial structure, novel weapons and resistance zones.

PubMed

Allstadt, Andrew; Caraco, Thomas; Molnár, F; Korniss, G

2012-08-07

Certain invasive plants may rely on interference mechanisms (e.g., allelopathy) to gain competitive superiority over native species. But expending resources on interference presumably exacts a cost in another life-history trait, so that the significance of interference competition for invasion ecology remains uncertain. We model ecological invasion when combined effects of preemptive and interference competition govern interactions at the neighborhood scale. We consider three cases. Under "novel weapons," only the initially rare invader exercises interference. For "resistance zones" only the resident species interferes, and finally we take both species as interference competitors. Interference increases the other species' mortality, opening space for colonization. However, a species exercising greater interference has reduced propagation, which can hinder its colonization of open sites. Interference never enhances a rare invader's growth in the homogeneously mixing approximation to our model. But interference can significantly increase an invader's competitiveness, and its growth when rare, if interactions are structured spatially. That is, interference can increase an invader's success when colonization of open sites depends on local, rather than global, species densities. In contrast, interference enhances the common, resident species' resistance to invasion independently of spatial structure, unless the propagation-cost is too great. The particular combination of propagation and interference producing the strongest biotic resistance in a resident species depends on the shape of the tradeoff between the two traits. Increases in background mortality (i.e., mortality not due to interference) always reduce the effectiveness of interference competition. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ecological niche comparison and molecular phylogeny segregate the invasive moss species Campylopus introflexus (Leucobryaceae, Bryophyta) from its closest relatives.

PubMed

Gama, Renato; Aguirre-Gutiérrez, Jesús; Stech, Michael

2017-10-01

The delimitation of the invasive moss species Campylopus introflexus from its closest relative, Campylopus pilifer , has been long debated based on morphology. Previous molecular phylogenetic reconstructions based on the nuclear ribosomal internal transcribed spacers (ITS) 1 and 2 showed that C. pilifer is split into an Old World and a New World lineage, but remained partly inconclusive concerning the relationships between these two clades and C. introflexus . Analyses of an extended ITS dataset displayed statistically supported incongruence between ITS1 and ITS2. ITS1 separates the New World clade of C. pilifer from a clade comprising C. introflexus and the Old World C. pilifer . Ancestral state reconstruction showed that this topology is morphologically supported by differences in the height of the dorsal costal lamellae in leaf cross-section (despite some overlap). ITS2, in contrast, supports the current morphological species concept, i.e., separating C. introflexus from C. pilifer , which is morphologically supported by the orientation of the hyaline hair point at leaf apex as well as costal lamellae height. Re-analysis of published and newly generated plastid atpB-rbcL spacer sequences supported the three ITS lineages. Ecological niche modeling proved a useful approach and showed that all three molecular lineages occupy distinct environmental spaces that are similar, but undoubtedly not equivalent. In line with the ITS1 topology, the C. pilifer lineage from the New World occupies the most distinct environmental niche, whereas the niches of Old World C. pilifer and C. introflexus are very similar. Taking the inferences from ecological niche comparisons, phylogenetics, and morphology together, we conclude that all three molecular lineages represent different taxa that should be recognized as independent species, viz. C. introflexus , C. pilifer (Old World clade), and the reinstated C. lamellatus Mont. (New World clade).

Biological control via "ecological" damping: An approach that attenuates non-target effects.

PubMed

Parshad, Rana D; Quansah, Emmanuel; Black, Kelly; Beauregard, Matthew

2016-03-01

In this work we develop and analyze a mathematical model of biological control to prevent or attenuate the explosive increase of an invasive species population, that functions as a top predator, in a three-species food chain. We allow for finite time blow-up in the model as a mathematical construct to mimic the explosive increase in population, enabling the species to reach "disastrous", and uncontrollable population levels, in a finite time. We next improve the mathematical model and incorporate controls that are shown to drive down the invasive population growth and, in certain cases, eliminate blow-up. Hence, the population does not reach an uncontrollable level. The controls avoid chemical treatments and/or natural enemy introduction, thus eliminating various non-target effects associated with such classical methods. We refer to these new controls as "ecological damping", as their inclusion dampens the invasive species population growth. Further, we improve prior results on the regularity and Turing instability of the three-species model that were derived in Parshad et al. (2014). Lastly, we confirm the existence of spatiotemporal chaos. Copyright © 2016 Elsevier Inc. All rights reserved.

Tumor evolution in space: the effects of competition colonization tradeoffs on tumor invasion dynamics.

PubMed

Orlando, Paul A; Gatenby, Robert A; Brown, Joel S

2013-01-01

We apply competition colonization tradeoff models to tumor growth and invasion dynamics to explore the hypothesis that varying selection forces will result in predictable phenotypic differences in cells at the tumor invasive front compared to those in the core. Spatially, ecologically, and evolutionarily explicit partial differential equation models of tumor growth confirm that spatial invasion produces selection pressure for motile phenotypes. The effects of the invasive phenotype on normal adjacent tissue determine the patterns of growth and phenotype distribution. If tumor cells do not destroy their environment, colonizer and competitive phenotypes coexist with the former localized at the invasion front and the latter, to the tumor interior. If tumors cells do destroy their environment, then cell motility is strongly selected resulting in accelerated invasion speed with time. Our results suggest that the widely observed genetic heterogeneity within cancers may not be the stochastic effect of random mutations. Rather, it may be the consequence of predictable variations in environmental selection forces and corresponding phenotypic adaptations.

Tumor Evolution in Space: The Effects of Competition Colonization Tradeoffs on Tumor Invasion Dynamics

PubMed Central

Orlando, Paul A.; Gatenby, Robert A.; Brown, Joel S.

2013-01-01

We apply competition colonization tradeoff models to tumor growth and invasion dynamics to explore the hypothesis that varying selection forces will result in predictable phenotypic differences in cells at the tumor invasive front compared to those in the core. Spatially, ecologically, and evolutionarily explicit partial differential equation models of tumor growth confirm that spatial invasion produces selection pressure for motile phenotypes. The effects of the invasive phenotype on normal adjacent tissue determine the patterns of growth and phenotype distribution. If tumor cells do not destroy their environment, colonizer and competitive phenotypes coexist with the former localized at the invasion front and the latter, to the tumor interior. If tumors cells do destroy their environment, then cell motility is strongly selected resulting in accelerated invasion speed with time. Our results suggest that the widely observed genetic heterogeneity within cancers may not be the stochastic effect of random mutations. Rather, it may be the consequence of predictable variations in environmental selection forces and corresponding phenotypic adaptations. PMID:23508890

Ecological consequences of interactions between ants and honeydew-producing insects

PubMed Central

Styrsky, John D; Eubanks, Micky D

2006-01-01

Interactions between ants and honeydew-producing hemipteran insects are abundant and widespread in arthropod food webs, yet their ecological consequences are very poorly known. Ant–hemipteran interactions have potentially broad ecological effects, because the presence of honeydew-producing hemipterans dramatically alters the abundance and predatory behaviour of ants on plants. We review several studies that investigate the consequences of ant–hemipteran interactions as ‘keystone interactions’ on arthropod communities and their host plants. Ant–hemipteran interactions have mostly negative effects on the local abundance and species richness of several guilds of herbivores and predators. In contrast, out of the 30 studies that document the effects of ant–hemipteran interactions on plants, the majority (73%) shows that plants actually benefit indirectly from these interactions. In these studies, increased predation or harassment of other, more damaging, herbivores by hemipteran-tending ants resulted in decreased plant damage and/or increased plant growth and reproduction. The ecological consequences of mutualistic interactions between honeydew-producing hemipterans and invasive ants relative to native ants have rarely been studied, but they may be of particular importance owing to the greater abundance, aggressiveness and extreme omnivory of invasive ants. We argue that ant–hemipteran interactions are largely overlooked and underappreciated interspecific interactions that have strong and pervasive effects on the communities in which they are embedded. PMID:17148245

Central-place foraging and ecological effects of an invasive predator across multiple habitats.

PubMed

Benkwitt, Cassandra E

2016-10-01

Cross-habitat foraging movements of predators can have widespread implications for predator and prey populations, community structure, nutrient transfer, and ecosystem function. Although central-place foraging models and other aspects of optimal foraging theory focus on individual predator behavior, they also provide useful frameworks for understanding the effects of predators on prey populations across multiple habitats. However, few studies have examined both the foraging behavior and ecological effects of nonnative predators across multiple habitats, and none has tested whether nonnative predators deplete prey in a manner predicted by these foraging models. I conducted behavioral observations of invasive lionfish (Pterois volitans) to determine whether they exhibit foraging movements similar to other central-place consumers. Then, I used a manipulative field experiment to test whether their effects on prey populations are consistent with three qualitative predictions from optimal foraging models. Specifically, I predicted that the effects of invasive lionfish on native prey will (1) occur at central sites first and then in surrounding habitats, (2) decrease with increasing distance away from their shelter site, and (3) extend to greater distances when prey patches are spaced closer together. Approximately 40% of lionfish exhibited short-term crepuscular foraging movements into surrounding habitats from the coral patch reefs where they shelter during daylight hours. Over the course of 7 weeks, lionfish depleted native fish populations on the coral patch reefs where they reside, and subsequently on small structures in the surrounding habitat. However, their effects did not decrease with increasing distance from the central shelter site and the influence of patch spacing was opposite the prediction. Instead, lionfish always had the greatest effects in areas with the highest prey densities. The differences between the predicted and observed effects of lionfish foraging are likely due to different constraints faced by invasive predators compared to native predators, namely that lionfish do not face increased predation risk with increased movement away from shelter sites. By foraging at greater distances from patch reefs than native predators, lionfish eliminated a spatial refuge from predation used by juveniles of many commercially and ecologically important reef fishes. © 2016 by the Ecological Society of America.

Systems modeling to improve the hydro-ecological performance of diked wetlands

NASA Astrophysics Data System (ADS)

Alminagorta, Omar; Rosenberg, David E.; Kettenring, Karin M.

2016-09-01

Water scarcity and invasive vegetation threaten arid-region wetlands and wetland managers seek ways to enhance wetland ecosystem services with limited water, labor, and financial resources. While prior systems modeling efforts have focused on water management to improve flow-based ecosystem and habitat objectives, here we consider water allocation and invasive vegetation management that jointly target the concurrent hydrologic and vegetation habitat needs of priority wetland bird species. We formulate a composite weighted usable area for wetlands (WU) objective function that represents the wetland surface area that provides suitable water level and vegetation cover conditions for priority bird species. Maximizing the WU is subject to constraints such as water balance, hydraulic infrastructure capacity, invasive vegetation growth and control, and a limited financial budget to control vegetation. We apply the model at the Bear River Migratory Bird Refuge on the Great Salt Lake, Utah, compare model-recommended management actions to past Refuge water and vegetation control activities, and find that managers can almost double the area of suitable habitat by more dynamically managing water levels and managing invasive vegetation in August at the beginning of the window for control operations. Scenario and sensitivity analyses show the importance to jointly consider hydrology and vegetation system components rather than only the hydrological component.

Two sides of a coin: Effects of climate change on the native and non-native distribution of Colossoma macropomum in South America.

PubMed

Lopes, Taise M; Bailly, Dayani; Almeida, Bia A; Santos, Natália C L; Gimenez, Barbara C G; Landgraf, Guilherme O; Sales, Paulo C L; Lima-Ribeiro, Matheus S; Cassemiro, Fernanda A S; Rangel, Thiago F; Diniz-Filho, José A F; Agostinho, Angelo A; Gomes, Luiz C

2017-01-01

Climate change and species invasions interact in nature, disrupting biological communities. Based on this knowledge, we simultaneously assessed the effects of climate change on the native distribution of the Amazonian fish Colossoma macropomum as well as on its invasiveness across river basins of South America, using ecological niche modeling. We used six niche models within the ensemble forecast context to predict the geographical distribution of C. macropomum for the present time, 2050 and 2080. Given that this species has been continuously introduced into non-native South American basins by fish farming activities, we added the locations of C. macropomum farms into the modeling process to obtain a more realistic scenario of its invasive potential. Based on modelling outputs we mapped climate refuge areas at different times. Our results showed that a plenty of climatically suitable areas for the occurrence of C. macropomum occurrence are located outside the original basins at the present time and that its invasive potential is greatly amplified by fish farms. Simulations of future geographic ranges revealed drastic range contraction in the native region, implying concerns not only with respect to the species conservation but also from a socio-economic perspective since the species is a cornerstone of artisanal and commercial fisheries in the Amazon. Although the invasive potential is projected to decrease in the face of climate change, climate refugia will concentrate in Paraná River, Southeast Atlantic and East Atlantic basins, putting intense, negative pressures on the native fish fauna these regions. Our findings show that short and long-term management actions are required for: i) the conservation of natural stocks of C. macropomum in the Amazon, and ii) protecting native fish fauna in the climate refuges of the invaded regions.

Two sides of a coin: Effects of climate change on the native and non-native distribution of Colossoma macropomum in South America

PubMed Central

Lopes, Taise M.; Bailly, Dayani; Almeida, Bia A.; Santos, Natália C. L.; Gimenez, Barbara C. G.; Landgraf, Guilherme O.; Sales, Paulo C. L.; Lima-Ribeiro, Matheus S.; Cassemiro, Fernanda A. S.; Rangel, Thiago F.; Diniz-Filho, José A. F.; Agostinho, Angelo A.; Gomes, Luiz C.

2017-01-01

Climate change and species invasions interact in nature, disrupting biological communities. Based on this knowledge, we simultaneously assessed the effects of climate change on the native distribution of the Amazonian fish Colossoma macropomum as well as on its invasiveness across river basins of South America, using ecological niche modeling. We used six niche models within the ensemble forecast context to predict the geographical distribution of C. macropomum for the present time, 2050 and 2080. Given that this species has been continuously introduced into non-native South American basins by fish farming activities, we added the locations of C. macropomum farms into the modeling process to obtain a more realistic scenario of its invasive potential. Based on modelling outputs we mapped climate refuge areas at different times. Our results showed that a plenty of climatically suitable areas for the occurrence of C. macropomum occurrence are located outside the original basins at the present time and that its invasive potential is greatly amplified by fish farms. Simulations of future geographic ranges revealed drastic range contraction in the native region, implying concerns not only with respect to the species conservation but also from a socio-economic perspective since the species is a cornerstone of artisanal and commercial fisheries in the Amazon. Although the invasive potential is projected to decrease in the face of climate change, climate refugia will concentrate in Paraná River, Southeast Atlantic and East Atlantic basins, putting intense, negative pressures on the native fish fauna these regions. Our findings show that short and long-term management actions are required for: i) the conservation of natural stocks of C. macropomum in the Amazon, and ii) protecting native fish fauna in the climate refuges of the invaded regions. PMID:28654663

Economic impacts of marine ecological change: Review and recent contributions of the VECTORS project on European marine waters

NASA Astrophysics Data System (ADS)

Groeneveld, Rolf A.; Bartelings, Heleen; Börger, Tobias; Bosello, Francesco; Buisman, Erik; Delpiazzo, Elisa; Eboli, Fabio; Fernandes, Jose A.; Hamon, Katell G.; Hattam, Caroline; Loureiro, Maria; Nunes, Paulo A. L. D.; Piwowarczyk, Joanna; Schasfoort, Femke E.; Simons, Sarah L.; Walker, Adam N.

2018-02-01

Marine ecological change is likely to have serious potential economic consequences for coastal economies all over the world. This article reviews the current literature on the economic impacts of marine ecological change, as well as a number of recent contributions to this literature carried out under the VECTORS project. We focus on three main types of change, namely invasive alien species; outbreak-forming species, such as jellyfish and toxic algae; and gradual changes in species distribution and productivity. The case studies available in the literature demonstrate that the impacts of invasions and outbreaks on fisheries, aquaculture, and tourism can potentially amount to several tens of millions of dollars each year in some regions. Moreover, stated preference studies suggest a substantial impact on coastal tourism and non-use values that is likely not visible in case studies of specific outbreak events. Climate-driven gradual changes in distribution and productivity of commercial fish stocks will have an impact on fisheries, although these impacts are likely to be overshadowed by much larger changes in prices of seafood and fuel.

Taxonomy, Ecology, and Management of Native and Exotic Fruit Fly Species in Africa.

PubMed

Ekesi, Sunday; De Meyer, Marc; Mohamed, Samira A; Virgilio, Massimiliano; Borgemeister, Christian

2016-01-01

Horticulture is one of the most important agricultural subsectors in Africa, providing income, creating employment opportunities, and enhancing food and nutritional security. However, tephritid fruit flies are responsible for both direct and indirect losses, with alien invasive species often having the most severe ecological and economic impact. In the past 20 years, systematic analysis of tephritids has provided comparative information on taxonomy, synonymy, and character-state differentiation. New molecular techniques are now available for identifying species, reconstructing phylogenies, and studying population genetic structures. Research on biology, host range and shifts, thermotolerance, and demography has provided useful information for developing predictive and ecological niche models to guide management methods. In recent years, the responses of various species to attractants have been documented. Several suppression methods, including the release of coevolved parasitoid species targeting invasives, have been promoted within the context of integrated pest management, leading to improvement in the quality and quantity of fruits and vegetables produced. However, there is still the need for wide-scale availability of these technologies to smallholder growers across Africa.

Statistical physics of community ecology: a cavity solution to MacArthur’s consumer resource model

NASA Astrophysics Data System (ADS)

Advani, Madhu; Bunin, Guy; Mehta, Pankaj

2018-03-01

A central question in ecology is to understand the ecological processes that shape community structure. Niche-based theories have emphasized the important role played by competition for maintaining species diversity. Many of these insights have been derived using MacArthur’s consumer resource model (MCRM) or its generalizations. Most theoretical work on the MCRM has focused on small ecosystems with a few species and resources. However theoretical insights derived from small ecosystems many not scale up to large ecosystems with many resources and species because large systems with many interacting components often display new emergent behaviors that cannot be understood or deduced from analyzing smaller systems. To address these shortcomings, we develop a statistical physics inspired cavity method to analyze MCRM when both the number of species and the number of resources is large. Unlike previous work in this limit, our theory addresses resource dynamics and resource depletion and demonstrates that species generically and consistently perturb their environments and significantly modify available ecological niches. We show how our cavity approach naturally generalizes niche theory to large ecosystems by accounting for the effect of collective phenomena on species invasion and ecological stability. Our theory suggests that such phenomena are a generic feature of large, natural ecosystems and must be taken into account when analyzing and interpreting community structure. It also highlights the important role that statistical-physics inspired approaches can play in furthering our understanding of ecology.

A cascade of destabilizations: Combining Wolbachia and Allee effects to eradicate insect pests.

PubMed

Blackwood, Julie C; Vargas, Roger; Fauvergue, Xavier

2018-01-01

The management of insect pests has long been dominated by the use of chemical insecticides, with the aim of instantaneously killing enough individuals to limit their damage. To minimize unwanted consequences, environmentally friendly approaches have been proposed that utilize biological control and take advantage of intrinsic demographic processes to reduce pest populations. We address the feasibility of a novel pest management strategy based on the release of insects infected with Wolbachia, which causes cytoplasmic incompatibilities in its host population, into a population with a pre-existing Allee effect. We hypothesize that the transient decline in population size caused by a successful invasion of Wolbachia can bring the population below its Allee threshold and, consequently, trigger extinction. We develop a stochastic population model that accounts for Wolbachia-induced cytoplasmic incompatibilities in addition to an Allee effect arising from mating failures at low population densities. Using our model, we identify conditions under which cytoplasmic incompatibilities and Allee effects successfully interact to drive insect pest populations towards extinction. Based on our results, we delineate control strategies based on introductions of Wolbachia-infected insects. We extend this analysis to evaluate control strategies that implement successive introductions of two incompatible Wolbachia strains. Additionally, we consider methods that combine Wolbachia invasion with mating disruption tactics to enhance the pre-existing Allee effect. We demonstrate that Wolbachia-induced cytoplasmic incompatibility and the Allee effect act independently from one another: the Allee effect does not modify the Wolbachia invasion threshold, and cytoplasmic incompatibilities only have a marginal effect on the Allee threshold. However, the interaction of these two processes can drive even large populations to extinction. The success of this method can be amplified by the introduction of multiple Wolbachia cytotypes as well as the addition of mating disruption. Our study extends the existing literature by proposing the use of Wolbachia introductions to capitalize on pre-existing Allee effects and consequently eradicate insect pests. More generally, it highlights the importance of transient dynamics, and the relevance of manipulating a cascade of destabilizatons for pest management. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

The association between urban trees and crime: Evidence from the spread of the emerald ash borer in Cincinnati

Treesearch

Michelle C. Kondo; SeungHoon Han; Geoffrey H. Donovan; John M. MacDonald

2017-01-01

The ecological impact of invasive tree pests is increasing worldwide. However, invasive tree pests may alsohave significant social costs. We investigated the association between the emerald ash borer (EAB)—aninvasive tree pest first discovered in the US in 2002—and crime in Cincinnati, Ohio. We used a natural experimental approach, and compared crime (in 11 classes) on...

Abundance of introduced species at home predicts abundance away in herbaceous communities

USGS Publications Warehouse

Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

2011-01-01

Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

[Research progress on the degradation mechanisms and restoration of riparian ecosystem].

PubMed

Huang, Kai; Guo, Huai-cheng; Liu, Yong; Yu, Ya-juan; Zhou, Feng

2007-06-01

Restoration and reconstruction of degraded riparian ecosystem caused by natural and anthropogenic disturbances is one of the important issues in restoration ecology and watershed ecology. The disturbances on riparian ecosystem include flow regime alteration, direct modification and watershed disturbance, which have different affecting mechanisms. Flow regime alteration affects riparian ecosystem by changing riparian soil humidity, oxidation-reduction potential, biotaliving environment, and sediment transfer; direct modification affects riparian vegetation diversity through human activities and exotic plants invasion; and watershed disturbance mainly manifests in the channel degradation, aggradation or widening, the lowering of groundwater table, and the modification in fluvial process. The assessment objects of riparian restoration are riparian ecosystem components, and the assessment indicators are shifted from ecological to synthetic indices. Riparian restoration should be based on the detailed understanding of the biological and physical processes which affect riparian ecosystem, and implemented by vegetation restoration and hydrological adjustment at watershed or landscape scale. To extend the research scales and objects and to apply interdisciplinary approaches should be the key points in the further studies on the degradation mechanisms and restoration of riparian ecosystem.

Predicting North American Scolytinae invasions in the Southern Hemisphere.

PubMed

Lantschner, Maria Victoria; Atkinson, Thomas H; Corley, Juan C; Liebhold, Andrew M

2017-01-01

Scolytinae species are recognized as one of the most important tree mortality agents in coniferous forests worldwide, and many are known invaders because they are easily transported in wood products. Nonnative trees planted in novel habitats often exhibit exceptional growth, in part because they escape herbivore (such as Scolytinae) pressure from their native range. Increasing accidental introductions of forest pest species as a consequence of international trade, however, is expected to diminish enemy release of nonnative forest trees. In this context, there is need to characterize patterns of forest herbivore species invasion risks at global scales. In this study, we analyze the establishment potential of 64 North American Scolytinae species in the Southern Hemisphere. We use climate-based ecological niche models (MaxEnt) to spatially define the potential distribution of these Scolytinae species in regions of the Southern Hemisphere were pines are planted. Our model predicts that all of the pine-growing regions of the Southern Hemisphere are capable of supporting some species of North American Scolytinae, but there are certain "hotspot" regions, southeastern Argentina, Bolivia, Chile, Peru and southwestern Australia, that appear to be suitable for a particularly large number of species. The species with the highest predicted risk of establishment were Dendroctonus valens, Xyleborus intrusus, Hylastes tenuis, Ips grandicollis, Gnathotrichus sulcatus, and Ips calligraphus. Given that global commerce is anticipated to continue to increase, we can expect that more Scolytinae species will continue to establish outside their range. Our results provide information useful for identifying a global list of potential invasive species in pine plantations, and may assist in the design of comprehensive strategies aimed at reducing pest establishment in Southern Hemisphere forest plantations. © 2016 by the Ecological Society of America.

Thermal ecological physiology of native and invasive frog species: do invaders perform better?

PubMed

Cortes, Pablo A; Puschel, Hans; Acuña, Paz; Bartheld, José L; Bozinovic, Francisco

2016-01-01

Biological invasions are recognized as an important biotic component of global change that threatens the composition, structure and functioning of ecosystems, resulting in loss of biodiversity and displacement of native species. Although ecological characteristics facilitating the establishment and spread of non-native species are widely recognized, little is known about organismal attributes underlying invasion success. In this study, we tested the effect of thermal acclimation on thermal tolerance and locomotor performance in the invasive Xenopus laevis and the Chilean native Calyptocephalella gayi . In particular, the maximal righting performance (μ MAX ), optimal temperature ( T O ), lower (CT min ) and upper critical thermal limits (CT max ), thermal breadth ( T br ) and the area under the performance curve (AUC) were studied after 6 weeks acclimation to 10 and 20°C. We observed higher values of μ max and AUC in X. laevis in comparison to C. gayi . On the contrary, the invasive species showed lower values of CT min in comparison to the native one. In contrast, CT max , T O and T br showed no inter-specific differences. Moreover, we found that both species have the ability to acclimate their locomotor performance and lower thermal tolerance limit at low temperatures. Our results demonstrate that X. laevis is a better performer than C. gayi . Although there were differences in CT min , the invasive and native frogs did not differ in their thermal tolerance. Interestingly, in both species the lower and upper critical thermal limits are beyond the minimal and maximal temperatures encountered in nature during the coldest and hottest month, respectively. Overall, our findings suggest that both X. laevis and C. gayi would be resilient to climate warming expectations in Chile.

Origin of the invasive Arundo donax (Poaceae): a trans-Asian expedition in herbaria.

PubMed

Hardion, Laurent; Verlaque, Régine; Saltonstall, Kristin; Leriche, Agathe; Vila, Bruno

2014-09-01

The hypothesis of an ancient introduction, i.e. archaeophyte origin, is one of the most challenging questions in phylogeography. Arundo donax (Poaceae) is currently considered to be one of the worst invasive species globally, but it has also been widely utilzed by man across Eurasia for millennia. Despite a lack of phylogenetic data, recent literature has often speculated on its introduction to the Mediterranean region. This study tests the hypothesis of its ancient introduction from Asia to the Mediterranean by using plastid DNA sequencing and morphometric analysis on 127 herbarium specimens collected across sub-tropical Eurasia. In addition, a bioclimatic species distribution model calibrated on 1221 Mediterranean localities was used to identify similar ecological niches in Asia. Despite analysis of several plastid DNA hypervariable sites and the identification of 13 haplotypes, A. donax was represented by a single haplotype from the Mediterranean to the Middle East. This haplotype is shared with invasive samples worldwide, and its nearest phylogenetic relatives are located in the Middle East. Morphometric data characterized this invasive clone by a robust morphotype distinguishable from all other Asian samples. The ecological niche modelling designated the southern Caspian Sea, southern Iran and the Indus Valley as the most suitable regions of origin in Asia for the invasive clone of A. donax. Using an integrative approach, an ancient dispersion of this robust, polyploid and non-fruiting clone is hypothesized from the Middle East to the west, leading to its invasion throughout the Mediterranean Basin. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A conceptual framework for invasion in microbial communities.

PubMed

Kinnunen, Marta; Dechesne, Arnaud; Proctor, Caitlin; Hammes, Frederik; Johnson, David; Quintela-Baluja, Marcos; Graham, David; Daffonchio, Daniele; Fodelianakis, Stilianos; Hahn, Nicole; Boon, Nico; Smets, Barth F

2016-12-01

There is a growing interest in controlling-promoting or avoiding-the invasion of microbial communities by new community members. Resource availability and community structure have been reported as determinants of invasion success. However, most invasion studies do not adhere to a coherent and consistent terminology nor always include rigorous interpretations of the processes behind invasion. Therefore, we suggest that a consistent set of definitions and a rigorous conceptual framework are needed. We define invasion in a microbial community as the establishment of an alien microbial type in a resident community and argue how simple criteria to define aliens, residents, and alien establishment can be applied for a wide variety of communities. In addition, we suggest an adoption of the community ecology framework advanced by Vellend (2010) to clarify potential determinants of invasion. This framework identifies four fundamental processes that control community dynamics: dispersal, selection, drift and diversification. While selection has received ample attention in microbial community invasion research, the three other processes are often overlooked. Here, we elaborate on the relevance of all four processes and conclude that invasion experiments should be designed to elucidate the role of dispersal, drift and diversification, in order to obtain a complete picture of invasion as a community process.

A conceptual framework for invasion in microbial communities

PubMed Central

Kinnunen, Marta; Dechesne, Arnaud; Proctor, Caitlin; Hammes, Frederik; Johnson, David; Quintela-Baluja, Marcos; Graham, David; Daffonchio, Daniele; Fodelianakis, Stilianos; Hahn, Nicole; Boon, Nico; Smets, Barth F

2016-01-01

There is a growing interest in controlling—promoting or avoiding—the invasion of microbial communities by new community members. Resource availability and community structure have been reported as determinants of invasion success. However, most invasion studies do not adhere to a coherent and consistent terminology nor always include rigorous interpretations of the processes behind invasion. Therefore, we suggest that a consistent set of definitions and a rigorous conceptual framework are needed. We define invasion in a microbial community as the establishment of an alien microbial type in a resident community and argue how simple criteria to define aliens, residents, and alien establishment can be applied for a wide variety of communities. In addition, we suggest an adoption of the community ecology framework advanced by Vellend (2010) to clarify potential determinants of invasion. This framework identifies four fundamental processes that control community dynamics: dispersal, selection, drift and diversification. While selection has received ample attention in microbial community invasion research, the three other processes are often overlooked. Here, we elaborate on the relevance of all four processes and conclude that invasion experiments should be designed to elucidate the role of dispersal, drift and diversification, in order to obtain a complete picture of invasion as a community process. PMID:27137125

The public and professionals reason similarly about the management of non-native invasive species: a quantitative investigation of the relationship between beliefs and attitudes.

PubMed

Fischer, Anke; Selge, Sebastian; van der Wal, René; Larson, Brendon M H

2014-01-01

Despite continued critique of the idea of clear boundaries between scientific and lay knowledge, the 'deficit-model' of public understanding of ecological issues still seems prevalent in discourses of biodiversity management. Prominent invasion biologists, for example, still argue that citizens need to be educated so that they accept scientists' views on the management of non-native invasive species. We conducted a questionnaire-based survey with members of the public and professionals in invasive species management (n = 732) in Canada and the UK to investigate commonalities and differences in their perceptions of species and, more importantly, how these perceptions were connected to attitudes towards species management. Both native and non-native mammal and tree species were included. Professionals tended to have more extreme views than the public, especially in relation to nativeness and abundance of a species. In both groups, species that were perceived to be more abundant, non-native, unattractive or harmful to nature and the economy were more likely to be regarded as in need of management. While perceptions of species and attitudes towards management thus often differed between public and professionals, these perceptions were linked to attitudes in very similar ways across the two groups. This suggests that ways of reasoning about invasive species employed by professionals and the public might be more compatible with each other than commonly thought. We recommend that managers and local people engage in open discussion about each other's beliefs and attitudes prior to an invasive species control programme. This could ultimately reduce conflict over invasive species control.

The Public and Professionals Reason Similarly about the Management of Non-Native Invasive Species: A Quantitative Investigation of the Relationship between Beliefs and Attitudes

PubMed Central

Fischer, Anke; Selge, Sebastian; van der Wal, René; Larson, Brendon M. H.

2014-01-01

Despite continued critique of the idea of clear boundaries between scientific and lay knowledge, the ‘deficit-model’ of public understanding of ecological issues still seems prevalent in discourses of biodiversity management. Prominent invasion biologists, for example, still argue that citizens need to be educated so that they accept scientists’ views on the management of non-native invasive species. We conducted a questionnaire-based survey with members of the public and professionals in invasive species management (n = 732) in Canada and the UK to investigate commonalities and differences in their perceptions of species and, more importantly, how these perceptions were connected to attitudes towards species management. Both native and non-native mammal and tree species were included. Professionals tended to have more extreme views than the public, especially in relation to nativeness and abundance of a species. In both groups, species that were perceived to be more abundant, non-native, unattractive or harmful to nature and the economy were more likely to be regarded as in need of management. While perceptions of species and attitudes towards management thus often differed between public and professionals, these perceptions were linked to attitudes in very similar ways across the two groups. This suggests that ways of reasoning about invasive species employed by professionals and the public might be more compatible with each other than commonly thought. We recommend that managers and local people engage in open discussion about each other’s beliefs and attitudes prior to an invasive species control programme. This could ultimately reduce conflict over invasive species control. PMID:25170957

Population genomic analyses reveal a history of range expansion and trait evolution across the native and invaded range of yellow starthistle (Centaurea solstitialis)

PubMed Central

BARKER, BRITTANY S.; ANDONIAN, KRIKOR; SWOPE, SARAH M.; LUSTER, DOUGLAS G.; DLUGOSCH, KATRINA M.

2017-01-01

Identifying sources of genetic variation and reconstructing invasion routes for non-native introduced species is central to understanding the circumstances under which they may evolve increased invasiveness. In this study, we used genome-wide single nucleotide polymorphisms to study the colonization history of Centaurea solstitialis in its native range in Eurasia and invasions into the Americas. We leveraged this information to pinpoint key evolutionary shifts in plant size, a focal trait associated with invasiveness in this species. Our analyses revealed clear population genomic structure of potential source populations in Eurasia, including deep differentiation of a lineage found in the southern Apennine and Balkan Peninsulas and divergence among populations in Asia, eastern Europe, and western Europe. We found strongest support for an evolutionary scenario in which western European populations were derived from an ancient admixture event between populations from eastern Europe and Asia, and subsequently served as the main genetic ‘bridgehead’ for introductions to the Americas. Introductions to California appear to be from a single source region, and multiple, independent introductions of divergent genotypes likely occurred into the Pacific Northwest. Plant size has evolved significantly at three points during range expansion, including a large size increase in the lineage responsible for the aggressive invasion of California’s interior. These results reveal a long history of colonization, admixture, and trait evolution in C. solstitialis, and suggest routes for improving evidence-based management decisions for one of the most ecologically and economically damaging invasive species in the western United States. PMID:28029713

The role thermal physiology plays in species invasion

PubMed Central

Kelley, Amanda L.

2014-01-01

The characterization of physiological phenotypes that may play a part in the establishment of non-native species can broaden our understanding about the ecology of species invasion. Here, an assessment was carried out by comparing the responses of invasive and native species to thermal stress. The goal was to identify physiological patterns that facilitate invasion success and to investigate whether these traits are widespread among invasive ectotherms. Four hypotheses were generated and tested using a review of the literature to determine whether they could be supported across taxonomically diverse invasive organisms. The four hypotheses are as follows: (i) broad geographical temperature tolerances (thermal width) confer a higher upper thermal tolerance threshold for invasive rather than native species; (ii) the upper thermal extreme experienced in nature is more highly correlated with upper thermal tolerance threshold for invasive vs. native animals; (iii) protein chaperone expression—a cellular mechanism that underlies an organism's thermal tolerance threshold—is greater in invasive organisms than in native ones; and (iv) acclimation to higher temperatures can promote a greater range of thermal tolerance for invasive compared with native species. Each hypothesis was supported by a meta-analysis of the invasive/thermal physiology literature, providing further evidence that physiology plays a substantial role in the establishment of invasive ectotherms. PMID:27293666

Mutualism between co-introduced species facilitates invasion and alters plant community structure

PubMed Central

Prior, Kirsten M.; Robinson, Jennifer M.; Meadley Dunphy, Shannon A.; Frederickson, Megan E.

2015-01-01

Generalized mutualisms are often predicted to be resilient to changes in partner identity. Variation in mutualism-related traits between native and invasive species however, can exacerbate the spread of invasive species (‘invasional meltdown’) if invasive partners strongly interact. Here we show how invasion by a seed-dispersing ant (Myrmica rubra) promotes recruitment of a co-introduced invasive over native ant-dispersed (myrmecochorous) plants. We created experimental communities of invasive (M. rubra) or native ants (Aphaenogaster rudis) and invasive and native plants and measured seed dispersal and plant recruitment. In our mesocosms, and in laboratory and field trials, M. rubra acted as a superior seed disperser relative to the native ant. By contrast, previous studies have found that invasive ants are often poor seed dispersers compared with native ants. Despite belonging to the same behavioural guild, seed-dispersing ants were not functionally redundant. Instead, native and invasive ants had strongly divergent effects on plant communities: the invasive plant dominated in the presence of the invasive ant and the native plants dominated in the presence of the native ant. Community changes were not due to preferences for coevolved partners: variation in functional traits of linked partners drove differences. Here, we show that strongly interacting introduced mutualists can be major drivers of ecological change. PMID:25540283

Biology and impacts of Pacific Islands invasive species. 14. Sus scrofa the feral pig (Artiodactyla: Suidae)

USGS Publications Warehouse

Wehr, Nathaniel H.; Hess, Steven C.; Litton, Creighton M.

2018-01-01

Feral pigs (Sus scrofa L.) are perhaps the most abundant, widespread, and economically significant large introduced vertebrate across the Pacific island region. Unlike many other nonnative invasive species, feral pigs have both cultural and recreational importance in the region, complicating their management. Today, Pacific island feral pigs are a mixture of several strains of domestic swine, Asiatic wild boar, and European wild boar. Due to their generalist diet and rooting behavior, feral pigs alter soils and watersheds and negatively impact native and nonnative flora and fauna. As a result, feral pigs have played a role in the extinction of several species of plants and animals on Pacific islands and have negative effects on both ecotourism and agricultural industries in the region. Despite numerous published studies on feral pigs in the Pacific island region, of which the majority include systematic analyses of original empirical data, some fundamental aspects of feral pig ecology remain poorly characterized, at least partly due to the remote and inaccessible environments that they often inhabit. To address these knowledge gaps, effort should be made to integrate research conducted outside the Pacific island region into local management strategies. This review summarizes the origins, history, ecology, environmental effects, and current management of feral pigs in the Pacific island region; integrates regional scientific findings with those of other insular and continental systems; and identifies current knowledge gaps requiring further research to inform the ecology and management of this impactful invasive species.

Chronic effects of an invasive species on an animal community.

PubMed

Doody, J Sean; Rhind, David; Green, Brian; Castellano, Christina; McHenry, Colin; Clulow, Simon

2017-08-01

Invasive species can trigger trophic cascades in animal communities, but published cases involving their removal of top predators are extremely rare. An exception is the invasive cane toad (Rhinella marina) in Australia, which has caused severe population declines in monitor lizards, triggering trophic cascades that facilitated dramatic and sometimes unexpected increases in several prey of the predators, including smaller lizards, snakes, turtles, crocodiles, and birds. Persistence of isolated populations of these predators with a decades-long sympatry with toads suggests the possibility of recovery, but alternative explanations are possible. Confirming predator recovery requires longer-term study of populations with both baseline and immediate post-invasion densities. Previously, we quantified short-term impacts of invasive cane toads on animal communities over seven years at two sites in tropical Australia. Herein, we test the hypothesis that predators have begun to recover by repeating the study 12 yr after the initial toad invasion. The three predatory lizards that experienced 71-97% declines in the short-term study showed no sign of recovery, and indeed a worse fate: two of the three species were no longer detectable in 630 km of river surveys, suggesting local extirpation. Two mesopredators that had increased markedly in the short term due to these predator losses showed diverse responses in the medium term; a small lizard species increased by ~500%, while populations of a snake species showed little change. Our results indicate a system still in ecological turmoil, having not yet reached a "new equilibrium" more than a decade after the initial invasion; predator losses due to this toxic invasive species, and thus downstream effects, were not transient. Given that cane toads have proven too prolific to eradicate or control, we suggest that recovery of impacted predators must occur unassisted by evolutionary means: dispersal into extinction sites from surviving populations with alleles for toxin resistance or toad avoidance. Evolution and subsequent dispersal may be the only solution for a number of species or communities affected by invasive species for which control is either prohibitively expensive, or not possible. © 2017 by the Ecological Society of America.

A spatial model to prioritize sagebrush landscapes in the intermountain west (U.S.A.) for restoration

USGS Publications Warehouse

Meinke, C.W.; Knick, S.T.; Pyke, D.A.

2009-01-01

The ecological integrity of Sagebrush (Artemisia spp.) ecosystems in the Intermountain West (U.S.A.) has been diminished by synergistic relationships among human activities, spread of invasive plants, and altered disturbance regimes. An aggressive effort to restore Sagebrush habitats is necessary if we are to stabilize or improve current habitat trajectories and reverse declining population trends of dependent wildlife. Existing economic resources, technical impediments, and logistic difficulties limit our efforts to a fraction of the extensive area undergoing fragmentation, degradation, and loss. We prioritized landscapes for restoring Sagebrush habitats within the intermountain western region of the United States using geographic information system (GIS) modeling techniques to identify areas meeting a set of conditions based on (1) optimum abiotic and biotic conditions favorable for revegetation of Sagebrush; (2) potential to increase connectivity of Sagebrush habitats in the landscape to benefit wildlife; (3) location of population strongholds for Greater Sage-Grouse (Centrocercus urophasianus, a species of conservation concern); and (4) potential impediments to successful restoration created by Cheatgrass (Bromus tectorum, an invasive exotic annual grass). Approximately 5.8 million ha in southwestern Idaho, northern Nevada, and eastern Oregon met our criteria for restoring Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) and 5.1 million ha had high priority for restoring Mountain big sagebrush (A. tridentata ssp. vaseyana). Our results represent an integral component in a hierarchical framework after which site-specific locations for treatments can be focused within high-priority areas. Using this approach, long-term restoration strategies can be implemented that combine local-scale treatments and objectives with large-scale ecological processes and priorities. ?? 2008 Society for Ecological Restoration International.

A decision support tool for adaptive management of native prairie ecosystems

USGS Publications Warehouse

Hunt, Victoria M.; Jacobi, Sarah; Gannon, Jill J.; Zorn, Jennifer E.; Moore, Clinton; Lonsdorf, Eric V.

2016-01-01

The Native Prairie Adaptive Management initiative is a decision support framework that provides cooperators with management-action recommendations to help them conserve native species and suppress invasive species on prairie lands. We developed a Web-based decision support tool (DST) for the U.S. Fish and Wildlife Service and the U.S. Geological Survey initiative. The DST facilitates cross-organizational data sharing, performs analyses to improve conservation delivery, and requires no technical expertise to operate. Each year since 2012, the DST has used monitoring data to update ecological knowledge that it translates into situation-specific management-action recommendations (e.g., controlled burn or prescribed graze). The DST provides annual recommendations for more than 10,000 acres on 20 refuge complexes in four U.S. states. We describe how the DST promotes the long-term implementation of the program for which it was designed and may facilitate decision support and improve ecological outcomes of other conservation efforts.

Twenty years of invasion: a review of round goby Neogobius melanostomus biology, spread and ecological implications.

PubMed

Kornis, M S; Mercado-Silva, N; Vander Zanden, M J

2012-02-01

The round goby Neogobius melanostomus is one of the most wide-ranging invasive fish on earth, with substantial introduced populations within the Laurentian Great Lakes watershed, the Baltic Sea and several major European rivers. Rapid expansion and deleterious ecosystem effects have motivated extensive research on this species; here this research is synthesized. Maps of the global distribution are provided and the invasion history of N. melanostomus, which spread more rapidly at first in North America, but has undergone substantial expansion over the past decade in the Baltic Sea, is summarized. Meta-analyses comparing their size at age, diet, competitors and predators in North American and European ecosystems are provided. Size at age is region specific, with saline habitats typically supporting larger and faster growing individuals than fresh water. Neogobius melanostomus prey differs substantially between regions, demonstrating a capacity to adapt to locally abundant food sources. Neogobius melanostomus comprise at least 50% of the diet of eight taxa in at least one site or life stage; in total, 16 predator taxa are documented from the Laurentian Great Lakes v. five from Eurasia. Invasive N. melanostomus are the only common forage fish to heavily exploit mussels in the Laurentian Great Lakes and the Baltic Sea, facilitating the transfer of energy from mussels to higher trophic levels in both systems. Neogobius melanostomus morphology, life history, reproduction, habitat preferences, environmental tolerances, parasites, environmental effects, sampling strategies and management are also discussed. Neogobius melanostomus inhabit a wide range of temperate freshwater and brackish-water ecosystems and will probably continue to spread via ballast water, accidental bait release and natural dispersal worldwide. Climate change will probably enhance N. melanostomus expansion by elevating water temperatures closer to its energetic optimum of 26° C. Future research needs are presented; most pressing are evaluating the economic effects of N. melanostomus invasion, determining long-term population level effects of egg predation on game-fish recruitment and comparing several variables (density, ecological effects morphology and life history) among invaded ecosystems. This review provides a central reference as researchers continue studying N. melanostomus, often as examples for advancing basic ecology and invasion biology. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Species distribution modeling based on the automated identification of citizen observations.

PubMed

Botella, Christophe; Joly, Alexis; Bonnet, Pierre; Monestiez, Pascal; Munoz, François

2018-02-01

A species distribution model computed with automatically identified plant observations was developed and evaluated to contribute to future ecological studies. We used deep learning techniques to automatically identify opportunistic plant observations made by citizens through a popular mobile application. We compared species distribution modeling of invasive alien plants based on these data to inventories made by experts. The trained models have a reasonable predictive effectiveness for some species, but they are biased by the massive presence of cultivated specimens. The method proposed here allows for fine-grained and regular monitoring of some species of interest based on opportunistic observations. More in-depth investigation of the typology of the observations and the sampling bias should help improve the approach in the future.

A field guide for selecting the most appropriate treatment in sagebrush and pinon-juniper ecosystems in the Great Basin: Evaluating resilience to disturbance and resistance to invasive annual grasses, and predicting vegetation response

Treesearch

Richard F. Miller; Jeanne C. Chambers; Mike Pellant

2014-01-01

This field guide identifies seven primary components that largely determine resilience to disturbance, as well as resistance to invasive grasses and plant succession following treatment of areas of concern. The primary components are (1) characteristics of the ecological site, (2) current vegetation prior to treatment, (3) disturbance history, (4) type, timing, and...

A new perspective on trait differences between native and invasive exotic plants.

PubMed

Leffler, A Joshua; James, Jeremy J; Monaco, Thomas A; Sheley, Roger L

2014-02-01

Functional differences between native and exotic species potentially constitute one factor responsible for plant invasion. Differences in trait values between native and exotic invasive species, however, should not be considered fixed and may depend on the context of the comparison. Furthermore, the magnitude of difference between native and exotic species necessary to trigger invasion is unknown. We propose a criterion that differences in trait values between a native and exotic invasive species must be greater than differences between co-occurring natives for this difference to be ecologically meaningful and a contributing factor to plant invasion. We used a meta-analysis to quantify the difference between native and exotic invasive species for various traits examined in previous studies and compared this value to differences among native species reported in the same studies. The effect size between native and exotic invasive species was similar to the effect size between co-occurring natives except for studies conducted in the field; in most instances, our criterion was not met although overall differences between native and exotic invasive species were slightly larger than differences between natives. Consequently, trait differences may be important in certain contexts, but other mechanisms of invasion are likely more important in most cases. We suggest that using trait values as predictors of invasion will be challenging.

[Distribution pattern of riparian invasive plants in Luanhe Basin, North China and its relationship with environment].

PubMed

Ren, Ying; He, Ping; Xu, Jie; Jia, Jiao

2017-06-18

In this study, the invasive plant species from the riparian vegetation in 56 sampling sites of Luanhe Basin were identified, and the correlations between their composition, spatial distribution and environmental factors were explored. In the basin, a total of 26 invasive species were registered, which belonged to 19 genera and 12 families, and 73.1% of them were annual plants. Asteraceae and Amaranthaceae were the two dominant families with the most invasive species, attributing to 50% of the total invasive species. Amaranthus retroflexus, Bidens frondosa and Chenopodium serotinum appeared with the highest frequencies. The number of invasive species and the invasive intensity at each site were significantly negatively correlated with the altitude. The distribution of invasive plants was significantly influenced by the intensity of human activities. The invasive plants were mainly distributed in the plain area, shallow mountainous area with many reservoirs, and the mountainous area with developed tourism around Chengde City, meanwhile, only few species with broad ecological amplitude existed in the plateau area. In general, species with higher invasive grades were mainly distributed in low and medium altitude areas below 400 m. Except for A. retroflexus, no high-grade invasive plants were discovered in high altitude area so far.

Indicators: Wetland Vegetation (Introduced Species)

EPA Pesticide Factsheets

Introduced plants are indicators of the ecological integrity of waters and evidence of increased human-caused disturbance in the watershed. Introduced species that cause economic or environmental harm, or harm to human health, are called invasive species.

Modelling biological invasions: species traits, species interactions, and habitat heterogeneity.

PubMed

Cannas, Sergio A; Marco, Diana E; Páez, Sergio A

2003-05-01

In this paper we explore the integration of different factors to understand, predict and control ecological invasions, through a general cellular automaton model especially developed. The model includes life history traits of several species in a modular structure interacting multiple cellular automata. We performed simulations using field values corresponding to the exotic Gleditsia triacanthos and native co-dominant trees in a montane area. Presence of G. triacanthos juvenile bank was a determinant condition for invasion success. Main parameters influencing invasion velocity were mean seed dispersal distance and minimum reproductive age. Seed production had a small influence on the invasion velocity. Velocities predicted by the model agreed well with estimations from field data. Values of population density predicted matched field values closely. The modular structure of the model, the explicit interaction between the invader and the native species, and the simplicity of parameters and transition rules are novel features of the model.

Invasion, Coexistence, and Extinction Driven by Preemptive Competition and Sex Ratio

NASA Astrophysics Data System (ADS)

Molnar, Ferenc; Caraco, Thomas; Korniss, Gyorgy

2012-02-01

We investigate competitive invasion in a simple population dynamics model, where females can differ genetically in the sex ratio of their offspring, and males can differ in mortality. Analyzing of the mean-field dynamics, we obtain conditions for ecological stability of a given sex-ratio allele for any mortality rate parameters. We also found that stable coexistence of the two alleles is possible, but only males can differ; one female phenotype is present. Our results show that the success of invasion is determined by the female birth sex ratio. A lower female ratio never excludes a larger female sex ratio; in case of coexistence, the surviving female phenotype always has the greater female sex ratio. Finally, we identified an interesting invasion-to-extinction scenario: successful invasion followed by extinction occurs when the invader initially propagates with the resident allele, but after excluding the resident, cannot survive on its own.

Coordination and plasticity in leaf anatomical traits of invasive and native vine species.

PubMed

Osunkoya, Olusegun O; Boyne, Richard; Scharaschkin, Tanya

2014-09-01

• Plant invasiveness can be promoted by higher values of adaptive traits (e.g., photosynthetic capacity, biomass accumulation), greater plasticity and coordination of these traits, and by higher and positive relative influence of these functionalities on fitness, such as increasing reproductive output. However, the data set for this premise rarely includes linkages between epidermal-stomatal traits, leaf internal anatomy, and physiological performance.• Three ecological pairs of invasive vs. noninvasive (native) woody vine species of South-East Queensland, Australia were investigated for trait differences in leaf morphology and anatomy under varying light intensity. The linkages of these traits with physiological performance (e.g., water-use efficiency, photosynthesis, and leaf construction cost) and plant adaptive traits of specific leaf area, biomass, and relative growth rates were also explored.• Except for stomatal size, mean leaf anatomical traits differed significantly between the two groups. Plasticity of traits and, to a very limited extent, their phenotypic integration were higher in the invasive relative to the native species. ANOVA, ordination, and analysis of similarity suggest that for leaf morphology and anatomy, the three functional strategies contribute to the differences between the two groups in the order phenotypic plasticity > trait means > phenotypic integration.• The linkages demonstrated in the study between stomatal complex/gross anatomy and physiology are scarce in the ecological literature of plant invasiveness, but the findings suggest that leaf anatomical traits need to be considered routinely as part of weed species assessment and in the worldwide leaf economic spectrum. © 2014 Botanical Society of America, Inc.

Effects of short-term invasion of Spartina alterniflora and the subsequent restoration of native mangroves on the soil organic carbon, nitrogen and phosphorus stock.

PubMed

Feng, Jianxiang; Zhou, Jian; Wang, Liming; Cui, Xiaowei; Ning, Cunxin; Wu, Hao; Zhu, Xiaoshan; Lin, Guanghui

2017-10-01

The exotic cordgrass Spartina alterniflora has severely invaded the mangrove wetlands in southern China and ecological restoration using native mangroves was conducted in an attempt to control this invasive species. In this study, the contents and pools of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) were quantified to investigate the invasive effects of S. alterniflora and then to evaluate whether the ecological restoration of native mangrove could reverse those effects. S. alterniflora only showed significantly higher organic carbon content in the surface 0-10 cm of soil than in the uninvaded mudflat. The high δ 13 C values in the surface soil of the invaded habitat demonstrated that S. alterniflora contributed 42.6-62.2% of the organic carbon. The SOC for invasive S. alterniflora and newly restored mangroves (4 years and 14 years) was not enhanced in comparison to the unvegetated mudflat. S. alterniflora significantly increased the surface soil TN content, but decreased the available phosphorus content and TP density. The TN densities increased gradually with the mangrove restoration, while the TP densities were only slightly influenced. The results suggested that short-term invasion of S. alterniflora and subsequent mangrove restoration did not alter SOC or TN pool sizes, but S. alterniflora was shown to affect the potential carbon storage capacity produced by the mangroves in the Zhangjiang Estuary. Copyright © 2017 Elsevier Ltd. All rights reserved.

Applications of Remote Sensing to Alien Invasive Plant Studies

PubMed Central

Huang, Cho-ying; Asner, Gregory P.

2009-01-01

Biological invasions can affect ecosystems across a wide spectrum of bioclimatic conditions. Therefore, it is often important to systematically monitor the spread of species over a broad region. Remote sensing has been an important tool for large-scale ecological studies in the past three decades, but it was not commonly used to study alien invasive plants until the mid 1990s. We synthesize previous research efforts on remote sensing of invasive plants from spatial, temporal and spectral perspectives. We also highlight a recently developed state-of-the-art image fusion technique that integrates passive and active energies concurrently collected by an imaging spectrometer and a scanning-waveform light detection and ranging (LiDAR) system, respectively. This approach provides a means to detect the structure and functional properties of invasive plants of different canopy levels. Finally, we summarize regional studies of biological invasions using remote sensing, discuss the limitations of remote sensing approaches, and highlight current research needs and future directions. PMID:22408558

Patterns of invasion and colonization of the sea lamprey (Petromyzon marinus) in North America as revealed by microsatellite genotypes.

PubMed

Bryan, M B; Zalinski, D; Filcek, K B; Libants, S; Li, W; Scribner, K T

2005-10-01

Invasions by exotic organisms have had devastating affects on aquatic ecosystems, both ecologically and economically. One striking example of a successful invader that has dramatically affected fish community structure in freshwater lakes of North America is the sea lamprey (Petromyzon marinus). We used eight microsatellite loci and multiple analytical techniques to examine competing hypotheses concerning the origins and colonization history of sea lamprey (n = 741). Analyses were based on replicated invasive populations from Lakes Erie, Huron, Michigan, and Superior, populations of unknown origins from Lakes Ontario, Champlain, and Cayuga, and populations of anadromous putative progenitor populations in North America and Europe. Populations in recently colonized lakes were each established by few colonists through a series of genetic bottlenecks which resulted in lower allelic diversity in more recently established populations. The spatial genetic structure of invasive populations differed from that of native populations on the Atlantic coast, reflecting founder events and connectivity of invaded habitats. Anadromous populations were found to be panmictic (theta(P) = 0.002; 95% CI = -0.003-0.006; P > 0.05). In contrast, there was significant genetic differentiation between populations in the lower and upper Great Lakes (theta(P) = 0.007; P < 0.05; 95% CI = 0.003-0.009). Populations in Lakes Ontario, Champlain, and Cayuga are native. Alternative models that describe different routes and timing of colonization of freshwater habitats were examined using coalescent-based analyses, and demonstrated that populations likely originated from natural migrations via the St Lawrence River.

Age, growth and population structure of invasive lionfish (Pterois volitans/miles) in northeast Florida using a length-based, age-structured population model.

PubMed

Johnson, Eric G; Swenarton, Mary Katherine

2016-01-01

The effective management of invasive species requires detailed understanding of the invader's life history. This information is essential for modeling population growth and predicting rates of expansion, quantifying ecological impacts and assessing the efficacy of removal and control strategies. Indo-Pacific lionfish ( Pterois volitans/miles ) have rapidly invaded the western Atlantic, Gulf of Mexico and Caribbean Sea with documented negative impacts on native ecosystems. To better understand the life history of this species, we developed and validated a length-based, age-structured model to investigate age, growth and population structure in northeast Florida. The main findings of this study were: (1) lionfish exhibited rapid growth with seasonal variation in growth rates; (2) distinct cohorts were clearly identifiable in the length-frequency data, suggesting that lionfish are recruiting during a relatively short period in summer; and (3) the majority of lionfish were less than two years old with no lionfish older than three years of age, which may be the result of culling efforts as well as ontogenetic habitat shifts to deeper water.

Age, growth and population structure of invasive lionfish (Pterois volitans/miles) in northeast Florida using a length-based, age-structured population model

PubMed Central

2016-01-01

The effective management of invasive species requires detailed understanding of the invader’s life history. This information is essential for modeling population growth and predicting rates of expansion, quantifying ecological impacts and assessing the efficacy of removal and control strategies. Indo-Pacific lionfish (Pterois volitans/miles) have rapidly invaded the western Atlantic, Gulf of Mexico and Caribbean Sea with documented negative impacts on native ecosystems. To better understand the life history of this species, we developed and validated a length-based, age-structured model to investigate age, growth and population structure in northeast Florida. The main findings of this study were: (1) lionfish exhibited rapid growth with seasonal variation in growth rates; (2) distinct cohorts were clearly identifiable in the length-frequency data, suggesting that lionfish are recruiting during a relatively short period in summer; and (3) the majority of lionfish were less than two years old with no lionfish older than three years of age, which may be the result of culling efforts as well as ontogenetic habitat shifts to deeper water. PMID:27920953

Dynamic social networks based on movement

USGS Publications Warehouse

Scharf, Henry; Hooten, Mevin B.; Fosdick, Bailey K.; Johnson, Devin S.; London, Joshua M.; Durban, John W.

2016-01-01

Network modeling techniques provide a means for quantifying social structure in populations of individuals. Data used to define social connectivity are often expensive to collect and based on case-specific, ad hoc criteria. Moreover, in applications involving animal social networks, collection of these data is often opportunistic and can be invasive. Frequently, the social network of interest for a given population is closely related to the way individuals move. Thus, telemetry data, which are minimally invasive and relatively inexpensive to collect, present an alternative source of information. We develop a framework for using telemetry data to infer social relationships among animals. To achieve this, we propose a Bayesian hierarchical model with an underlying dynamic social network controlling movement of individuals via two mechanisms: an attractive effect and an aligning effect. We demonstrate the model and its ability to accurately identify complex social behavior in simulation, and apply our model to telemetry data arising from killer whales. Using auxiliary information about the study population, we investigate model validity and find the inferred dynamic social network is consistent with killer whale ecology and expert knowledge.

Genomic Diversity and the Microenvironment as Drivers of Progression in DCIS

DTIC Science & Technology

2015-10-01

progress to invasive breast cancer. We have applied for and received ethical approval to carry out the study at our primary site, and have completed a...cancer, and the application of ecological and other spatial statistics to those images 1-4. 24 Month Milestones: 3 • IHC staining of candidate...Athena Aktipis and Yinyin Yuan: An ecological measure of immune-cancer colocalization as a prognostic factor for breast cancer. Under review at Breast

Population ecology of the sea lamprey (Petromyzon marinus) as an invasive species in the Laurentian Great Lakes and an imperiled species in Europe

USGS Publications Warehouse

Hansen, Michael J.; Madenjian, Charles P.; Slade, Jeffrey W.; Steeves, Todd B.; Almeida, Pedro R.; Quintella, Bernardo R.

2016-01-01

The sea lamprey Petromyzon marinus (Linnaeus) is both an invasive non-native species in the Laurentian Great Lakes of North America and an imperiled species in much of its native range in North America and Europe. To compare and contrast how understanding of population ecology is useful for control programs in the Great Lakes and restoration programs in Europe, we review current understanding of the population ecology of the sea lamprey in its native and introduced range. Some attributes of sea lamprey population ecology are particularly useful for both control programs in the Great Lakes and restoration programs in the native range. First, traps within fish ladders are beneficial for removing sea lampreys in Great Lakes streams and passing sea lampreys in the native range. Second, attractants and repellants are suitable for luring sea lampreys into traps for control in the Great Lakes and guiding sea lamprey passage for conservation in the native range. Third, assessment methods used for targeting sea lamprey control in the Great Lakes are useful for targeting habitat protection in the native range. Last, assessment methods used to quantify numbers of all life stages of sea lampreys would be appropriate for measuring success of control in the Great Lakes and success of conservation in the native range.

Genetics reveal the identity and origin of the lionfish invasion in the Mediterranean Sea.

PubMed

Bariche, Michel; Kleitou, Periklis; Kalogirou, Stefanos; Bernardi, Giacomo

2017-07-28

Following aquarium releases, invasive lionfishes have colonized large areas of the Caribbean and western Atlantic, resulting in an immense ecological damage. The early stages of that invasion are poorly known. Indeed, a lag of time between the introduction and detection often preclude genetic characterization of that crucial phase. With elevated awareness, the recent invasion of Pterois miles was quickly detected in the Mediterranean Sea. We hereby show that the very first individuals establishing populations in the Mediterranean Sea display haplotypes that nest within the large genetic diversity of Red Sea individuals, thus indicating an invasion via the Suez Canal. We also show that only two haplotypes are detected in the Mediterranean Sea, suggesting that few individuals may have been involved in the invasion. Thus, we conclude that the Mediterranean invasion is the result of a movement of individuals from the Red Sea, rather than from other means, and that low genetic diversity does not seem to have a negative effect on the success and spread of lionfish into the Mediterranean Sea.

Invasive plants transform the three-dimensional structure of rain forests

PubMed Central

Asner, Gregory P.; Hughes, R. Flint; Vitousek, Peter M.; Knapp, David E.; Kennedy-Bowdoin, Ty; Boardman, Joseph; Martin, Roberta E.; Eastwood, Michael; Green, Robert O.

2008-01-01

Biological invasions contribute to global environmental change, but the dynamics and consequences of most invasions are difficult to assess at regional scales. We deployed an airborne remote sensing system that mapped the location and impacts of five highly invasive plant species across 221,875 ha of Hawaiian ecosystems, identifying four distinct ways that these species transform the three-dimensional (3D) structure of native rain forests. In lowland to montane forests, three invasive tree species replace native midcanopy and understory plants, whereas one understory invader excludes native species at the ground level. A fifth invasive nitrogen-fixing tree, in combination with a midcanopy alien tree, replaces native plants at all canopy levels in lowland forests. We conclude that this diverse array of alien plant species, each representing a different growth form or functional type, is changing the fundamental 3D structure of native Hawaiian rain forests. Our work also demonstrates how an airborne mapping strategy can identify and track the spread of certain invasive plant species, determine ecological consequences of their proliferation, and provide detailed geographic information to conservation and management efforts. PMID:18316720

Evidence of Adaptive Evolutionary Divergence during Biological Invasion

PubMed Central

Lucek, Kay; Sivasundar, Arjun; Seehausen, Ole

2012-01-01

Rapid phenotypic diversification during biological invasions can either arise by adaptation to alternative environments or by adaptive phenotypic plasticity. Where experimental evidence for adaptive plasticity is common, support for evolutionary diversification is rare. Here, we performed a controlled laboratory experiment using full-sib crosses between ecologically divergent threespine stickleback populations to test for a genetic basis of adaptation. Our populations are from two very different habitats, lake and stream, of a recently invaded range in Switzerland and differ in ecologically relevant morphological traits. We found that in a lake-like food treatment lake fish grow faster than stream fish, resembling the difference among wild type individuals. In contrast, in a stream-like food treatment individuals from both populations grow similarly. Our experimental data suggest that genetically determined diversification has occurred within less than 140 years after the arrival of stickleback in our studied region. PMID:23152900

Assessing Environmental Risks for Established Invasive Weeds: Dalmatian (Linaria dalmatica) and Yellow (L. vulgaris) Toadflax in North America

PubMed Central

Sing, Sharlene E.; Peterson, Robert K. D.

2011-01-01

Environmental risk assessments characterizing potential environmental impacts of exotic weeds are more abundant and comprehensive for potential or new invaders than for widespread and well-established species such as Dalmatian (Linaria dalmatica [L.] Mill.) and yellow (L. vulgaris Mill.) toadflax. Specific effects evaluated in our assessment of environmental risks posed by yellow and Dalmatian toadflax included competitive displacement of other plant species, reservoirs of plant disease, animal and insect use, animal toxicity, human toxicity and allergenicity, erosion, and wildfire. Effect and exposure uncertainties for potential impacts of toadflax on human and ecological receptors were rated. Using publicly available information we were able to characterize ecological and human health impacts associated with toadflax, and to identify specific data gaps contributing to a high uncertainty of risk. Evidence supporting perceived negative environmental impacts of invasive toadflax was scarce. PMID:21845161

Assessing environmental risks for established invasive weeds: Dalmatian (Linaria dalmatica) and yellow (L. vulgaris) toadflax in North America.

PubMed

Sing, Sharlene E; Peterson, Robert K D

2011-07-01

Environmental risk assessments characterizing potential environmental impacts of exotic weeds are more abundant and comprehensive for potential or new invaders than for widespread and well-established species such as Dalmatian (Linaria dalmatica [L.] Mill.) and yellow (L. vulgaris Mill.) toadflax. Specific effects evaluated in our assessment of environmental risks posed by yellow and Dalmatian toadflax included competitive displacement of other plant species, reservoirs of plant disease, animal and insect use, animal toxicity, human toxicity and allergenicity, erosion, and wildfire. Effect and exposure uncertainties for potential impacts of toadflax on human and ecological receptors were rated. Using publicly available information we were able to characterize ecological and human health impacts associated with toadflax, and to identify specific data gaps contributing to a high uncertainty of risk. Evidence supporting perceived negative environmental impacts of invasive toadflax was scarce.

Continental faunal exchange and the asymmetrical radiation of carnivores.

PubMed

Pires, Mathias M; Silvestro, Daniele; Quental, Tiago B

2015-10-22

Lineages arriving on islands may undergo explosive evolutionary radiations owing to the wealth of ecological opportunities. Although studies on insular taxa have improved our understanding of macroevolutionary phenomena, we know little about the macroevolutionary dynamics of continental exchanges. Here we study the evolution of eight Carnivora families that have migrated across the Northern Hemisphere to investigate if continental invasions also result in explosive diversification dynamics. We used a Bayesian approach to estimate speciation and extinction rates from a substantial dataset of fossil occurrences while accounting for the incompleteness of the fossil record. Our analyses revealed a strongly asymmetrical pattern in which North American lineages invading Eurasia underwent explosive radiations, whereas lineages invading North America maintained uniform diversification dynamics. These invasions into Eurasia were characterized by high rates of speciation and extinction. The radiation of the arriving lineages in Eurasia coincide with the decline of established lineages or phases of climate change, suggesting differences in the ecological settings between the continents may be responsible for the disparity in diversification dynamics. These results reveal long-term outcomes of biological invasions and show that the importance of explosive radiations in shaping diversity extends beyond insular systems and have significant impact at continental scales. © 2015 The Author(s).

Continental faunal exchange and the asymmetrical radiation of carnivores

PubMed Central

Pires, Mathias M.; Silvestro, Daniele; Quental, Tiago B.

2015-01-01

Lineages arriving on islands may undergo explosive evolutionary radiations owing to the wealth of ecological opportunities. Although studies on insular taxa have improved our understanding of macroevolutionary phenomena, we know little about the macroevolutionary dynamics of continental exchanges. Here we study the evolution of eight Carnivora families that have migrated across the Northern Hemisphere to investigate if continental invasions also result in explosive diversification dynamics. We used a Bayesian approach to estimate speciation and extinction rates from a substantial dataset of fossil occurrences while accounting for the incompleteness of the fossil record. Our analyses revealed a strongly asymmetrical pattern in which North American lineages invading Eurasia underwent explosive radiations, whereas lineages invading North America maintained uniform diversification dynamics. These invasions into Eurasia were characterized by high rates of speciation and extinction. The radiation of the arriving lineages in Eurasia coincide with the decline of established lineages or phases of climate change, suggesting differences in the ecological settings between the continents may be responsible for the disparity in diversification dynamics. These results reveal long-term outcomes of biological invasions and show that the importance of explosive radiations in shaping diversity extends beyond insular systems and have significant impact at continental scales. PMID:26490792

In situ relationships between microbiota and potential pathobiota in Arabidopsis thaliana.

PubMed

Bartoli, Claudia; Frachon, Léa; Barret, Matthieu; Rigal, Mylène; Huard-Chauveau, Carine; Mayjonade, Baptiste; Zanchetta, Catherine; Bouchez, Olivier; Roby, Dominique; Carrère, Sébastien; Roux, Fabrice

2018-05-30

A current challenge in microbial pathogenesis is to identify biological control agents that may prevent and/or limit host invasion by microbial pathogens. In natura, hosts are often infected by multiple pathogens. However, most of the current studies have been performed under laboratory controlled conditions and by taking into account the interaction between a single commensal species and a single pathogenic species. The next step is therefore to explore the relationships between host-microbial communities (microbiota) and microbial members with potential pathogenic behavior (pathobiota) in a realistic ecological context. In the present study, we investigated such relationships within root-associated and leaf-associated bacterial communities of 163 ecologically contrasted Arabidopsis thaliana populations sampled across two seasons in southwest of France. In agreement with the theory of the invasion paradox, we observed a significant humped-back relationship between microbiota and pathobiota α-diversity that was robust between both seasons and plant organs. In most populations, we also observed a strong dynamics of microbiota composition between seasons. Accordingly, the potential pathobiota composition was explained by combinations of season-specific microbiota operational taxonomic units. This result suggests that the potential biomarkers controlling pathogen's invasion are highly dynamic.

Ecological implications of behavioural syndromes.

PubMed

Sih, Andrew; Cote, Julien; Evans, Mara; Fogarty, Sean; Pruitt, Jonathan

2012-03-01

Interspecific trait variation has long served as a conceptual foundation for our understanding of ecological patterns and dynamics. In particular, ecologists recognise the important role that animal behaviour plays in shaping ecological processes. An emerging area of interest in animal behaviour, the study of behavioural syndromes (animal personalities) considers how limited behavioural plasticity, as well as behavioural correlations affects an individual's fitness in diverse ecological contexts. In this article we explore how insights from the concept and study of behavioural syndromes provide fresh understanding of major issues in population ecology. We identify several general mechanisms for how population ecology phenomena can be influenced by a species or population's average behavioural type, by within-species variation in behavioural type, or by behavioural correlations across time or across ecological contexts. We note, in particular, the importance of behavioural type-dependent dispersal in spatial ecology. We then review recent literature and provide new syntheses for how these general mechanisms produce novel insights on five major issues in population ecology: (1) limits to species' distribution and abundance; (2) species interactions; (3) population dynamics; (4) relative responses to human-induced rapid environmental change; and (5) ecological invasions. © 2012 Blackwell Publishing Ltd/CNRS.

Educational outreach and impacts of white-tailed deer browse on native and invasive plants at the Crooked Creek Environmental Learning Center, Armstrong County, Pennsylvania

NASA Astrophysics Data System (ADS)

Lindsay, Lisa O.

Overabundance of deer can assist the intrusion of invasive plants through browse, leading to homogenization of plant communities. Public attitudes towards native and invasive plant species and white-tailed deer browse related to personal experiences, can be changed through education focusing public awareness of ramifications of deer browse on native and invasive plants. I developed an interactive, interpretive Self-Guided Walking Tour brochure of the "You Can Trail" to provide an educational outreach program for visitors of Crooked Creek Environmental Learning Center that includes ecologically important native and invasive plants species from my investigation. This research study focuses on the overall abundance of native and invasive plant species once Odocoileus virginianus have been removed from the landscape during collection periods in June and September 2013 from exclosure and access plots that were maintained for seven years. Similarity of abundance were found in native and invasive abundance of forbs, bushes and percentage of ground cover. Differences included native bush volume being greater than invasive bush volume in the access plot in June with opposing results in the exclosure plot, being greater in invasive bush volume. However, in September, native and invasive bush volume was similar within the exclosure plot, while invasive bush volume decreased in the access plot. Invasive vines recorded in the June access plot were absent in the September collection period.

Multi-Phase US Spread and Habitat Switching of a Post-Columbian Invasive, Sorghum halepense

PubMed Central

Barney, Jacob N.; Atwater, Daniel Z.; Pederson, Gary A.; Pederson, Jeffrey F.; Chandler, J. Mike; Cox, T. Stan; Cox, Sheila; Dotray, Peter; Kopec, David; Smith, Steven E.; Schroeder, Jill; Wright, Steven D.; Jiao, Yuannian; Kong, Wenqian; Goff, Valorie; Auckland, Susan; Rainville, Lisa K.; Pierce, Gary J.; Lemke, Cornelia; Compton, Rosana; Phillips, Christine; Kerr, Alexandra; Mettler, Matthew; Paterson, Andrew H.

2016-01-01

Johnsongrass (Sorghum halepense) is a striking example of a post-Columbian founder event. This natural experiment within ecological time-scales provides a unique opportunity for understanding patterns of continent-wide genetic diversity following range expansion. Microsatellite markers were used for population genetic analyses including leaf-optimized Neighbor-Joining tree, pairwise FST, mismatch analysis, principle coordinate analysis, Tajima’s D, Fu’s F and Bayesian clusterings of population structure. Evidence indicates two geographically distant introductions of divergent genotypes, which spread across much of the US in <200 years. Based on geophylogeny, gene flow patterns can be inferred to have involved five phases. Centers of genetic diversity have shifted from two introduction sites separated by ~2000 miles toward the middle of the range, consistent with admixture between genotypes from the respective introductions. Genotyping provides evidence for a ‘habitat switch’ from agricultural to non-agricultural systems and may contribute to both Johnsongrass ubiquity and aggressiveness. Despite lower and more structured diversity at the invasion front, Johnsongrass continues to advance northward into cooler and drier habitats. Association genetic approaches may permit identification of alleles contributing to the habitat switch or other traits important to weed/invasive management and/or crop improvement. PMID:27755565

The Catastrophic Failure of Plant Hydraulic Networks Examined in Leaves

NASA Astrophysics Data System (ADS)

Marmottant, Philippe; Bienaimé, Diane; Brodribb, Timothy

Plants live a dangerous game: they have to facilitate water transport in their xylem conduits while minimizing the consequence of hydraulic failure. Indeed, as water flows under negative pressure inside these conduits, cavitation bubbles can spontaneously occur. By preventing the sap transport, they could lead to the plant death. This failure dynamics of this hydraulic network is poorly studied, while it has important ecological and bioengineering implications. Here, by using a simple optical method, we were able to directly visualize the spreading of cavitation bubbles within leaves. The air invasion also progresses by stop and go, from largest veins to smallest ones. In fact, in plants, conducts are linked by small valves called pits. By temporarily blocking bubbles they delay air invasion, until the pressure difference exceeds a threshold. To test the impact of these singular valves on the air invasion, we build a simulation based on the electrokinetic analogy. Taking in account the elasticity of the channel, each conduct becomes a hydraulic resistance coupled with a capacity. We show that we can reproduce the stop and go propagation in a variety of different network architectures. ERC Bubbleboost Grant number 614655.

Regional consequences of a biotic interchange: insights from the Lessepsian invasion

NASA Astrophysics Data System (ADS)

Nawrot, Rafal; Albano, Paolo G.; Chattopadhyay, Devapriya; Zuschin, Martin

2016-04-01

The fossil record provides ample evidence of large-scale biotic interchanges and their pervasive effects on regional biotas, but mechanisms controlling such events are difficult to decipher in deep time. Massive invasion of Indo-Pacific species into the Mediterranean Sea triggered by the opening of the Suez Canal offers a unique opportunity to examine the ecological consequences of breaking down biogeographic barriers. We developed an extensive database of taxonomic composition, body size and ecological characteristics of the Red Sea and Mediterranean bivalve fauna in order to link biotic selectivity of the invasion process with its effects on the recipient biota. Shallow-water occurrence and presence outside the tropical zone in other regions are the strongest predictors of the successful transition through the Suez Canal. Subsequent establishment of alien species in the Mediterranean Sea correlates with early arrival and preference for hard substrates. Finally, large-bodied species and hard-bottom dwellers are over-represented among the invasive aliens that have reached the spread stage and impose a strong impact on native communities. Although body size is important only at the last invasion stage, alien species are significantly larger compared to native Mediterranean bivalves. This reflects biogeographic difference in the body-size distributions of the source and recipient species pools related to the recent geological history of the Mediterranean Sea. Contrary to the general expectations on the effects of temperature on average body size, continued warming of the Mediterranean Sea accelerates the entry of tropical aliens and thus indirectly leads to increase in the proportion of large-bodied species in local communities and the regional biota. Invasion-driven shifts in species composition are stronger in hard-substrate communities, which host a smaller pool of incumbent species and are more susceptible to the establishment of newcomers. Analogous differences between habitats and body-size classes in the invasion levels have been observed in some marine biotic interchanges documented in the fossil record. Further quantitative studies of past invasion events are necessary to test generality of these patterns.

On the context-dependent scaling of consumer feeding rates.

PubMed

Barrios-O'Neill, Daniel; Kelly, Ruth; Dick, Jaimie T A; Ricciardi, Anthony; MacIsaac, Hugh J; Emmerson, Mark C

2016-06-01

The stability of consumer-resource systems can depend on the form of feeding interactions (i.e. functional responses). Size-based models predict interactions - and thus stability - based on consumer-resource size ratios. However, little is known about how interaction contexts (e.g. simple or complex habitats) might alter scaling relationships. Addressing this, we experimentally measured interactions between a large size range of aquatic predators (4-6400 mg over 1347 feeding trials) and an invasive prey that transitions among habitats: from the water column (3D interactions) to simple and complex benthic substrates (2D interactions). Simple and complex substrates mediated successive reductions in capture rates - particularly around the unimodal optimum - and promoted prey population stability in model simulations. Many real consumer-resource systems transition between 2D and 3D interactions, and along complexity gradients. Thus, Context-Dependent Scaling (CDS) of feeding interactions could represent an unrecognised aspect of food webs, and quantifying the extent of CDS might enhance predictive ecology. © The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Restoration treatments in urban park forests drive long-term changes in vegetation trajectories.

PubMed

Johnson, Lea R; Handel, Steven N

2016-04-01

Municipalities are turning to ecological restoration of urban forests as a measure to improve air quality, ameliorate urban heat island effects, improve storm water infiltration, and provide other social and ecological benefits. However, community dynamics following urban forest restoration treatments are poorly documented. This study examines the long-term effects of ecological restoration undertaken in New York City, New York, USA, to restore native forest in urban park natural areas invaded by woody non-native plants that are regional problems. In 2009 and 2010, we sampled vegetation in 30 invaded sites in three large public parks that were restored 1988-1993, and 30 sites in three large parks that were similarly invaded but had not been restored. Data from these matched plots reveal that the restoration treatment achieved its central goals. After 15-20 years, invasive species removal followed by native tree planting resulted in persistent structural and compositional shifts, significantly lower invasive species abundance, a more complex forest structure, and greater native tree recruitment. Together, these findings indicate that successional trajectories of vegetation dynamics have diverged between restored forests and invaded forests that were not restored. In addition, the data suggest that future composition of these urban forest patches will be novel assemblages. Restored and untreated sites shared a suite of shade-intolerant, quickly-growing tree species that colonize disturbed sites, indicating that restoration treatments created sites hospitable for germination and growth of species adapted to high light conditions and disturbed soils. These findings yield an urban perspective on the use of succession theory in ecological restoration. Models of ecological restoration developed in more pristine environments must be modified for use in cities. By anticipating both urban disturbances and ecological succession, management of urban forest patches can be adjusted to better predict and direct long-term outcomes. An urban approach to ecological restoration must use realistic, flexible targets to preserve and enhance urban biodiversity for both short-term benefits and long-term sustainability.

Functional Group, Biomass, and Climate Change Effects on Ecological Drought in Semiarid Grasslands

NASA Astrophysics Data System (ADS)

Wilson, S. D.; Schlaepfer, D. R.; Bradford, J. B.; Lauenroth, W. K.; Duniway, M. C.; Hall, S. A.; Jamiyansharav, K.; Jia, G.; Lkhagva, A.; Munson, S. M.; Pyke, D. A.; Tietjen, B.

2018-03-01

Water relations in plant communities are influenced both by contrasting functional groups (grasses and shrubs) and by climate change via complex effects on interception, uptake, and transpiration. We modeled the effects of functional group replacement and biomass increase, both of which can be outcomes of invasion and vegetation management, and climate change on ecological drought (soil water potential below which photosynthesis stops) in 340 semiarid grassland sites over 30 year periods. Relative to control vegetation (climate and site-determined mixes of functional groups), the frequency and duration of drought were increased by shrubs and decreased by annual grasses. The rankings of shrubs, control vegetation, and annual grasses in terms of drought effects were generally consistent in current and future climates, suggesting that current differences among functional groups on drought effects predict future differences. Climate change accompanied by experimentally increased biomass (i.e., the effects of invasions that increase community biomass or management that increases productivity through fertilization or respite from grazing) increased drought frequency and duration and advanced drought onset. Our results suggest that the replacement of perennial temperate semiarid grasslands by shrubs, or increased biomass, can increase ecological drought in both current and future climates.

Functional group, biomass, and climate change effects on ecological drought in semiarid grasslands

USGS Publications Warehouse

Wilson, Scott D.; Schlaepfer, Daniel R.; Bradford, John B.; Lauenroth, William K.; Duniway, Michael C.; Hall, Sonia A.; Jamiyansharav, Khishigbayar; Jia, Gensuo; Lkhagva, Ariuntsetseg; Munson, Seth M.; Pyke, David A.; Tietjen, Britta

2018-01-01

Water relations in plant communities are influenced both by contrasting functional groups (grasses, shrubs) and by climate change via complex effects on interception, uptake and transpiration. We modelled the effects of functional group replacement and biomass increase, both of which can be outcomes of invasion and vegetation management, and climate change on ecological drought (soil water potential below which photosynthesis stops) in 340 semiarid grassland sites over 30‐year periods. Relative to control vegetation (climate and site‐determined mixes of functional groups), the frequency and duration of drought were increased by shrubs and decreased by annual grasses. The rankings of shrubs, control vegetation, and annual grasses in terms of drought effects were generally consistent in current and future climates, suggesting that current differences among functional groups on drought effects predict future differences. Climate change accompanied by experimentally‐increased biomass (i.e. the effects of invasions that increase community biomass, or management that increases productivity through fertilization or respite from grazing) increased drought frequency and duration, and advanced drought onset. Our results suggest that the replacement of perennial temperate semiarid grasslands by shrubs, or increased biomass, can increase ecological drought both in current and future climates.

From ground pools to treeholes: convergent evolution of habitat and phenotype in Aedes mosquitoes.

PubMed

Soghigian, John; Andreadis, Theodore G; Livdahl, Todd P

2017-12-19

Invasive mosquito species are responsible for millions of vector-borne disease cases annually. The global invasive success of Aedes mosquitoes such as Aedes aegypti and Aedes albopictus has relied on the human transport of immature stages in container habitats. However, despite the importance of these mosquitoes and this ecological specialization to their widespread dispersal, evolution of habitat specialization in this group has remained largely unstudied. We use comparative methods to evaluate the evolution of habitat specialization and its potential influence on larval morphology, and evaluate whether container dwelling and invasiveness are monophyletic in Aedes. We show that habitat specialization has evolved repeatedly from ancestral ground pool usage to specialization in container habitats. Furthermore, we find that larval morphological scores are significantly associated with larval habitat when accounting for evolutionary relationships. We find that Ornstein-Uhleinbeck models with unique optima for each larval habitat type are preferred over several other models based predominantly on neutral processes, and that OU models can reliably simulate real morphological data. Our results demonstrate that multiple lineages of Aedes have convergently evolved a key trait associated with invasive success: the use of container habitats for immature stages. Moreover, our results demonstrate convergence in morphological characteristics as well, and suggest a role of adaptation to habitat specialization in driving phenotypic diversity in this mosquito lineage. Finally, our results highlight that the genus Aedes is not monophyletic.

The role of hybridization in facilitating tree invasion

PubMed Central

2017-01-01

Abstract Hybridization events can generate additional genetic diversity upon which natural selection can act and at times enhance invasiveness of the species. Invasive tree species are a growing ecological concern worldwide, and some of these invasions involve hybridization events pre- or post-introduction. There are 20 hybrid invasive tree taxa in 15 genera (11 plant families) discussed here. When reported, abundance of hybrids comprised 10–100 % of an invasion, the remainder being parental taxa. In seven hybrid taxa, researchers identified phenotypes that may make hybrids better invaders. Twelve hybrid tree taxa involved introgression and more hybrids involved all non-native taxa than native × non-native taxa. Three hybrid tree taxa were the result of intentional crosses, and all hybrid taxa involved intentional introduction of either one or more parental taxon or the hybrid itself. The knowledge gaps present in some hybrid tree taxa can weaken our effectiveness in predicting and controlling invasions, as hybrids can add a level of complexity to an invasion by being morphologically cryptic, causing genetic pollution of a native parental taxon, presenting novel genotypes for which there may not be coevolved biological control agents, or evolving adaptive traits through increased genetic variation. PMID:28028055

Specific leaf area relates to the differences in leaf construction cost, photosynthesis, nitrogen allocation, and use efficiencies between invasive and noninvasive alien congeners.

PubMed

Feng, Yu-Long; Fu, Gai-Lan; Zheng, Yu-Long

2008-08-01

Comparisons between invasive and native species may not characterize the traits of invasive species, as native species might be invasive elsewhere if they were introduced. In this study, invasive Oxalis corymbosa and Peperomia pellucida were compared with their respective noninvasive alien congeners. We hypothesized that the invasive species have higher specific leaf (SLA) than their respective noninvasive alien congeners, and analyzed the physiological and ecological consequences of the higher SLA. Higher SLA was indeed the most important trait for the two invaders, which was associated with their lower leaf construction cost, higher nitrogen (N) allocation to photosynthesis and photosynthetic N use efficiency (PNUE). The higher N allocation to photosynthesis of the invaders in turn increased their PNUE, N content in photosynthesis, biochemical capacity for photosynthesis, and therefore light-saturated photosynthetic rate. The above resource capture-, use- and growth-related traits may facilitate the two invaders' invasion, while further comparative studies on a wider range of invasive and noninvasive congeners are needed to understand the generality of this pattern and to fully assess the competitive advantages afforded by these traits.

Anthropogenic Disturbance Can Determine the Magnitude of Opportunistic Species Responses on Marine Urban Infrastructures

PubMed Central

Airoldi, Laura; Bulleri, Fabio

2011-01-01

Background Coastal landscapes are being transformed as a consequence of the increasing demand for infrastructures to sustain residential, commercial and tourist activities. Thus, intertidal and shallow marine habitats are largely being replaced by a variety of artificial substrata (e.g. breakwaters, seawalls, jetties). Understanding the ecological functioning of these artificial habitats is key to planning their design and management, in order to minimise their impacts and to improve their potential to contribute to marine biodiversity and ecosystem functioning. Nonetheless, little effort has been made to assess the role of human disturbances in shaping the structure of assemblages on marine artificial infrastructures. We tested the hypothesis that some negative impacts associated with the expansion of opportunistic and invasive species on urban infrastructures can be related to the severe human disturbances that are typical of these environments, such as those from maintenance and renovation works. Methodology/Principal Findings Maintenance caused a marked decrease in the cover of dominant space occupiers, such as mussels and oysters, and a significant enhancement of opportunistic and invasive forms, such as biofilm and macroalgae. These effects were particularly pronounced on sheltered substrata compared to exposed substrata. Experimental application of the disturbance in winter reduced the magnitude of the impacts compared to application in spring or summer. We use these results to identify possible management strategies to inform the improvement of the ecological value of artificial marine infrastructures. Conclusions/Significance We demonstrate that some of the impacts of globally expanding marine urban infrastructures, such as those related to the spread of opportunistic, and invasive species could be mitigated through ecologically-driven planning and management of long-term maintenance of these structures. Impact mitigation is a possible outcome of policies that consider the ecological features of built infrastructures and the fundamental value of controlling biodiversity in marine urban systems. PMID:21826224

Federal collaboration in science for invasive mammal management in U.S. National Parks and Wildlife Refuges of the Pacific Islands

USGS Publications Warehouse

Hess, Steven C.; Hu, Darcy; Loh, Rhonda; Banko, Paul C.; Conner, L.M.; Smith, M.D.

2016-01-01

Some of the most isolated islands in the Pacific Ocean are home to US National Parks and Wildlife Refuges. These islands are known for flora and fauna that occur nowhere else, but also for invasive species and other factors which have resulted in the disproportionate extinction of native species. The control of invasive mammals is the single most expensive natural resource management activity essential for restoring ecological integrity to parks in the Hawaiian Islands, American Samoa, and the islands of Guam and Saipan. Science-based applications supporting management efforts have been shaped by longstanding collaborative federal research programs over the past four decades. Consequently, feral goats (Capra hircus) have been removed from >690 km2 in National Parks, and feral pigs (Sus scrofa) have been removed from >367 km2 of federal lands of Hawai‘i, bringing about the gradual recovery of forest ecosystems. The exclusion of other non-native ungulates and invasive mammals is now being undertaken with more sophisticated control techniques and fences. New fence designs are now capable of excluding feral cats (Felis catus) from large areas to protect endangered native waterfowl and nesting seabirds. Rodenticides which have been tested and registered for hand and aerial broadcast in Hawai‘i have been used to eradicate rats from small offshore islands to protect nesting seabirds and are now being applied to montane environments of larger islands to protect forest birds. Forward-looking infrared radar (FLIR) is also being applied to locate wild ungulates which were more recently introduced to some islands. All invasive mammals have been eradicated from some remote small islands, and it may soon be possible to manage areas on larger islands to be free of invasive mammals at least during seasonally important periods for native species.

Simulating the effects of climate change on the distribution of an invasive plant, using a high resolution, local scale, mechanistic approach: challenges and insights.

PubMed

Fennell, Mark; Murphy, James E; Gallagher, Tommy; Osborne, Bruce

2013-04-01

The growing economic and ecological damage associated with biological invasions, which will likely be exacerbated by climate change, necessitates improved projections of invasive spread. Generally, potential changes in species distribution are investigated using climate envelope models; however, the reliability of such models has been questioned and they are not suitable for use at local scales. At this scale, mechanistic models are more appropriate. This paper discusses some key requirements for mechanistic models and utilises a newly developed model (PSS[gt]) that incorporates the influence of habitat type and related features (e.g., roads and rivers), as well as demographic processes and propagule dispersal dynamics, to model climate induced changes in the distribution of an invasive plant (Gunnera tinctoria) at a local scale. A new methodology is introduced, dynamic baseline benchmarking, which distinguishes climate-induced alterations in species distributions from other potential drivers of change. Using this approach, it was concluded that climate change, based on IPCC and C4i projections, has the potential to increase the spread-rate and intensity of G. tinctoria invasions. Increases in the number of individuals were primarily due to intensification of invasion in areas already invaded or in areas projected to be invaded in the dynamic baseline scenario. Temperature had the largest influence on changes in plant distributions. Water availability also had a large influence and introduced the most uncertainty in the projections. Additionally, due to the difficulties of parameterising models such as this, the process has been streamlined by utilising methods for estimating unknown variables and selecting only essential parameters. © 2012 Blackwell Publishing Ltd.

Molecules, morphology, and ecology indicate a recent, amphibious ancestry for echidnas.

PubMed

Phillips, Matthew J; Bennett, Thomas H; Lee, Michael S Y

2009-10-06

The semiaquatic platypus and terrestrial echidnas (spiny anteaters) are the only living egg-laying mammals (monotremes). The fossil record has provided few clues as to their origins and the evolution of their ecological specializations; however, recent reassignment of the Early Cretaceous Teinolophos and Steropodon to the platypus lineage implies that platypuses and echidnas diverged >112.5 million years ago, reinforcing the notion of monotremes as living fossils. This placement is based primarily on characters related to a single feature, the enlarged mandibular canal, which supplies blood vessels and dense electrosensory receptors to the platypus bill. Our reevaluation of the morphological data instead groups platypus and echidnas to the exclusion of Teinolophos and Steropodon and suggests that an enlarged mandibular canal is ancestral for monotremes (partly reversed in echidnas, in association with general mandibular reduction). A multigene evaluation of the echidna-platypus divergence using both a relaxed molecular clock and direct fossil calibrations reveals a recent split of 19-48 million years ago. Platypus-like monotremes (Monotrematum) predate this divergence, indicating that echidnas had aquatically foraging ancestors that reinvaded terrestrial ecosystems. This ecological shift and the associated radiation of echidnas represent a recent expansion of niche space despite potential competition from marsupials. Monotremes might have survived the invasion of marsupials into Australasia by exploiting ecological niches in which marsupials are restricted by their reproductive mode. Morphology, ecology, and molecular biology together indicate that Teinolophos and Steropodon are basal monotremes rather than platypus relatives, and that living monotremes are a relatively recent radiation.

Density matters: Approaches to settling ballast water discharge concentrations

EPA Science Inventory

A consensus has evolved that invasion risk increases with propagule pressure. However, translating this general principal into ecologically “acceptable” concentrations of organisms in ballast water has proven challenging. The treaty being promulgated by the International Maritime...

Biotic Invasions: Causes, Epidemiology, Global Consequences and Control

EPA Pesticide Factsheets

The module provides a link to an article in a series of articles in Issues in Ecology. This article presents information on biotic invaders, their destruction, controlling their detriment and the effects aquaculture is having on world fish supplies.

Canopy and knowledge gaps when invasive alien insects remove foundation species.

PubMed

Marler, Thomas E; Lawrence, John H

2013-01-01

The armored scale Aulacaspis yasumatsui invaded the northern range of the cycad Cycas micronesica in 2003, and epidemic tree mortality ensued due to a lack of natural enemies of the insect. We quantified cycad demographic responses to the invasion, but the ecological responses to the selective removal of this foundation species have not been addressed. We use this case to highlight information gaps in our understanding of how alien invasive phytophagous insects force cascading adverse ecosystem changes. The mechanistic role of unique canopy gaps, oceanic island examples and threatened foundation species with distinctive traits are three issues that deserve research efforts in a quest to understand this facet of ecosystem change occurring across multiple settings globally.

Invasion complexity at large spatial scales is an emergent property of interactions among landscape characteristics and invader traits

PubMed Central

Jordan, Nicholas R.; Forester, James D.

2018-01-01

Invasion potential should be part of the evaluation of candidate species for any species introduction. However, estimating invasion risks remains a challenging problem, particularly in complex landscapes. Certain plant traits are generally considered to increase invasive potential and there is an understanding that landscapes influence invasions dynamics, but little research has been done to explore how those drivers of invasions interact. We evaluate the relative roles of, and potential interactions between, plant invasiveness traits and landscape characteristics on invasions with a case study using a model parameterized for the potentially invasive biomass crop, Miscanthus × giganteus. Using that model we simulate invasions on 1000 real landscapes to evaluate how landscape characteristics, including both composition and spatial structure, affect invasion outcomes. We conducted replicate simulations with differing strengths of plant invasiveness traits (dispersal ability, establishment ability, population growth rate, and the ability to utilize dispersal corridors) to evaluate how the importance of landscape characteristics for predicting invasion patterns changes depending on the invader details. Analysis of simulations showed that the presence of highly suitable habitat (e.g., grasslands) is generally the strongest determinant of invasion dynamics but that there are also more subtle interactions between landscapes and invader traits. These effects can also vary between different aspects of invasion dynamics (short vs. long time scales and population size vs. spatial extent). These results illustrate that invasions are complex emergent processes with multiple drivers and effective management needs to reflect the ecology of the species of interest and the particular goals or risks for which efforts need to be optimized. PMID:29771923

Ecological genetics at the USGS National Wetlands Research Center

USGS Publications Warehouse

Travis, Steven

2006-01-01

The Ecological Genetics Program at the USGS National Wetlands Research Center (NWRC) employs state-of-the-art DNA fingerprinting technologies in characterizing critical management aspects of the population biology of species of concern (fig. 1). The overarching themes of this program have been (1) the critical role that genetic diversity plays in maintaining population viability and (2) how management strategies might incorporate genetic information in preventing the decline of desirable species or in controlling the spread of invasive species.

Ecological equivalency as a tool for endangered species management.

PubMed

Searcy, Christopher A; Rollins, Hilary B; Shaffer, H Bradley

2016-01-01

The use of taxon substitutes for extinct or endangered species is a controversial conservation measure. We use the example of the endangered California tiger salamander (Ambystoma californiense; CTS), which is being replaced by hybrids with the invasive barred tiger salamander (Ambystoma mavortium), to illustrate a strategy for evaluating taxon substitutes based on their position in a multivariate community space. Approximately one-quarter of CTS's range is currently occupied by "full hybrids" with 70% nonnative genes, while another one-quarter is occupied by "superinvasives" where a specific set of 3/68 genes comprising 4% of the surveyed genome is nonnative. Based on previous surveys of natural CTS breeding ponds, we stocked experimental mesocosms with field-verified, realistic densities of tiger salamander larvae and their prey, and used these mesocosms to evaluate ecological equivalency between pure CTS, full hybrids, and superinvasives in experimental pond communities. We also included a fourth treatment with no salamanders present to evaluate the community effects of eliminating Ambystoma larvae altogether. We found that pure CTS and superinvasive larvae were ecologically equivalent, because their positions in the multivariate community space were statistically indistinguishable and they did not differ significantly along any univariate community axes. Full hybrids were ecologically similar, but not equivalent, to the other two genotypes, and the no-Ambystoma treatment was by far the most divergent. We conclude that, at least for the larval stage, superinvasives are adequate taxon substitutes for pure CTS and should probably be afforded protection under the Endangered Species Act. The proper conservation status for full hybrids remains debatable.

A social–ecological perspective for riverscape management in the Columbia River Basin

USGS Publications Warehouse

Hand, Brian K.; Flint, Courtney G.; Frissell, Chris A.; Muhlfeld, Clint C.; Devlin, Shawn P.; Kennedy, Brian P.; Crabtree, Robert L.; McKee, W. Arthur; Luikart, Gordon; Stanford, Jack A.

2018-01-01

Riverscapes are complex, landscape-scale mosaics of connected river and stream habitats embedded in diverse ecological and socioeconomic settings. Social–ecological interactions among stakeholders often complicate natural-resource conservation and management of riverscapes. The management challenges posed by the conservation and restoration of wild salmonid populations in the Columbia River Basin (CRB) of western North America are one such example. Because of their ecological, cultural, and socioeconomic importance, salmonids present a complex management landscape due to interacting environmental factors (eg climate change, invasive species) as well as socioeconomic and political factors (eg dams, hatcheries, land-use change, transboundary agreements). Many of the problems in the CRB can be linked to social–ecological interactions occurring within integrated ecological, human–social, and regional–climatic spheres. Future management and conservation of salmonid populations therefore depends on how well the issues are understood and whether they can be resolved through effective communication and collaboration among ecologists, social scientists, stakeholders, and policy makers.

Bio-invasive ascidians in Ireland: A threat for the shellfish industry but also a source of high added value products.

PubMed

Palanisamy, Satheesh Kumar; Thomas, Olivier P; P McCormack, Grace

2018-01-01

In October 2016, a rapid assessment survey of ascidian species was conducted in shellfish farms at Killary Fjord, in the west of Ireland. Two non-indigenous solitary ascidians Ascidiella aspersa and Corella eumoyta were recorded for the first time in shellfish farms at this location. Both invasive ascidians have the potential to greatly reduce mussel production in Killary Fjord by competing with shellfish for food and habitat. Their high abundance also causes an increase in maintenance costs leading to economic losses for aquaculture farmers. Prompted by our finding of two invasive ascidians in Killary Fjord, we provide a brief review of the ecological role of ascidians and the potential of harnessing biomass from such invasive species for the production of high added value marine natural products.

Evolutionary responses of native plant species to invasive plants: a review.

PubMed

Oduor, Ayub M O

2013-12-01

Strong competition from invasive plant species often leads to declines in abundances and may, in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species,suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has involved experiments comparing two conspecific groups of native plants for differences in expression of growth/reproductive traits: populations that have experienced competition from the invasive plant species (i.e. experienced natives) versus populations with no known history of interactions with the invasive plant species (i.e. naıve natives). Here, I employ a meta-analysis to obtain a general pattern of inferred evolutionary responses of native plant species from 53 such studies. In general, the experienced natives had significantly higher growth/reproductive performances than naıve natives, when grown with or without competition from invasive plants.While the current results indicate that certain populations of native plant species could potentially adapt evolutionarily to invasive plant species, the ecological and evolutionary mechanisms that probably underlie such evolutionary responses remain unexplored and should be the focus of future studies.

Exploring and Describing the Spatial & Temporal Dynamics of Medushead in the Channeled Scablands of Eastern Washington Using Remote Sensing Techniques

NASA Astrophysics Data System (ADS)

Bateman, Timothy M.

Medusahead is a harmful weed that is invading public lands in the West. The invasion is a serious concern to the public because it can reduce forage for livestock and wildlife, increase fire frequency, alter important ecosystem cycles (like water), reduce recreational activities, and produce landscapes that are aesthetically unpleasing. Invasions can drive up costs that generally require taxpayer's dollars. Medusahead seedlings typically spread to new areas by attaching itself to passing objects (e.g. vehicles, animals, clothing) where it can quickly begin to affect plants communities. To be effective, management plans need to be sustainable, informed, and considerate to invasion levels across large landscapes. Ecological remote sensing analysis is a method that uses airborne imagery, taken from drones, aircrafts, or satellites, to gather information about ecological systems. This Thesis strived to use remote sensing techniques to identify medusahead in the landscape and its changes through time. This was done for an extensive area of rangelands in the Channel Scabland region of eastern ashington. This Thesis provided results that would benefit land managers that include: 1) a dispersal map of medusahead, 2) a time line of medusahead cover through time, 3) 'high risk' dispersal areas, 4) climatic factors showing an influence on the time line of medusahead, 5) a strategy map that can be utilized by land managers to direct management needs. This Thesis shows how remote sensing applications can be used to detect medusahead in the landscape and understand its invasiveness through time. This information can help create sustainable and effective management plans so land managers can continue to protect and improve western public lands threatened by the invasion of medusahead.

Invading and expanding: range dynamics and ecological consequences of the greater white-toothed shrew (Crocidura russula) invasion in Ireland.

PubMed

McDevitt, Allan D; Montgomery, W Ian; Tosh, David G; Lusby, John; Reid, Neil; White, Thomas A; McDevitt, C Damien; O'Halloran, John; Searle, Jeremy B; Yearsley, Jon M

2014-01-01

Establishing how invasive species impact upon pre-existing species is a fundamental question in ecology and conservation biology. The greater white-toothed shrew (Crocidura russula) is an invasive species in Ireland that was first recorded in 2007 and which, according to initial data, may be limiting the abundance/distribution of the pygmy shrew (Sorex minutus), previously Ireland's only shrew species. Because of these concerns, we undertook an intensive live-trapping survey (and used other data from live-trapping, sightings and bird of prey pellets/nest inspections collected between 2006 and 2013) to model the distribution and expansion of C. russula in Ireland and its impacts on Ireland's small mammal community. The main distribution range of C. russula was found to be approximately 7,600 km2 in 2013, with established outlier populations suggesting that the species is dispersing with human assistance within the island. The species is expanding rapidly for a small mammal, with a radial expansion rate of 5.5 km/yr overall (2008-2013), and independent estimates from live-trapping in 2012-2013 showing rates of 2.4-14.1 km/yr, 0.5-7.1 km/yr and 0-5.6 km/yr depending on the landscape features present. S. minutus is negatively associated with C. russula. S. minutus is completely absent at sites where C. russula is established and is only present at sites at the edge of and beyond the invasion range of C. russula. The speed of this invasion and the homogenous nature of the Irish landscape may mean that S. minutus has not had sufficient time to adapt to the sudden appearance of C. russula. This may mean the continued decline/disappearance of S. minutus as C. russula spreads throughout the island.

Seed wasp invasions promoted by unregulated seed trade affect vegetal and animal biodiversity.

PubMed

Auger-Rozenberg, Marie-Anne; Roques, Alain

2012-09-01

Cone and seed insects are considered the most important predators of tree seeds during the pre-dispersal phase of development. Among them, exotic seed chalcids in the genus Megastigmus invaded Europe as a result of the rapidly-increasing and mostly unregulated seed trade for afforestation and ornamental plantations. Unlike their economic impact in seed orchards, until recently, little attention was paid to the ecological impact of these insects. In the present study, selected case studies of alien Megastigmus spp. were considered to assess their specific impact on the potential of natural regeneration of native woody plants and on the native entomofauna competing for seed resource. We re-analyzed data from former studies that did not focus on these ecological interactions and, here, present previously unpublished results. Seeds of Douglas-fir, true cedars, true firs and wild roses were sampled all over Europe, and the relative importance of the native and invasive chalcid species was assessed as well as their specific impact on seed yield. In most cases, the recent arrival of alien chalcids resulted in a significant decrease in the regeneration potential of the host trees. In the absence of competitors, alien chalcids occupied the entire seed niche in Douglas-fir, but their impact tended to decrease after the arrival of invasive seed bugs. In firs, alien chalcids tended to displace the native chalcids, but not in wild roses and cedars, where their damage was increasing. Different biological traits that might explain invasive success of alien chalcids are discussed. However, no general invasive patterns seem to exist. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

Detecting trends in regional ecosystem functioning: the importance of field data for calibrating and validating NEON airborne remote sensing instruments and science data products

NASA Astrophysics Data System (ADS)

McCorkel, J.; Kuester, M. A.; Johnson, B. R.; Krause, K.; Kampe, T. U.; Moore, D. J.

2011-12-01

The National Ecological Observatory Network (NEON) is a research facility under development by the National Science Foundation to improve our understanding of and ability to forecast the impacts of climate change, land-use change, and invasive species on ecology. The infrastructure, designed to operate over 30 years or more, includes site-based flux tower and field measurements, coordinated with airborne remote sensing observations to observe key ecological processes over a broad range of temporal and spatial scales. NEON airborne data on vegetation biochemical, biophysical, and structural properties and on land use and land cover will be captured at 1 to 2 meter resolution by an imaging spectrometer, a small-footprint waveform-LiDAR and a high-resolution digital camera. Annual coverage of the 60 NEON sites and capacity to support directed research flights or respond to unexpected events will require three airborne observation platforms (AOP). The integration of field and airborne data with satellite observations and other national geospatial data for analysis, monitoring and input to ecosystem models will extend NEON observations to regions across the United States not directly sampled by the observatory. The different spatial scales and measurement methods make quantitative comparisons between remote sensing and field data, typically collected over small sample plots (e.g. < 0.2 ha), difficult. New approaches to developing temporal and spatial scaling relationships between these data are necessary to enable validation of airborne and satellite remote sensing data and for incorporation of these data into continental or global scale ecological models. In addition to consideration of the methods used to collect ground-based measurements, careful calibration of the remote sensing instrumentation and an assessment of the accuracy of algorithms used to derive higher-level science data products are needed. Furthermore, long-term consistency of the data collected by all three airborne instrument packages over the NEON sites requires traceability of the calibration to national standards, field-based verification of instrument calibration and stability in the aircraft environment, and an independent assessment of the quality of derived data products. This work describes the development of the calibration laboratory, early evaluation of field-based vicarious calibration, development of scaling relationships, and test flights. Complementary laboratory- and field-based calibration of the AOP in addition to consistency with on-board calibration methods provide confidence that low-level data such as radiance and surface reflectance measurements are accurate and comparable among different sensors. Algorithms that calculate higher-level data products including essential climate variables will be validated against equivalent ground- and satellite-based results. Such a validated data set across multiple spatial and temporal scales is key to enabling ecosystem models to forecast the effects of climate change, land-use change and invasive species on the continental scale.

Temporal Patterns of Abundance of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) and Mitochondrial DNA Analysis of Ae. albopictus in the Central African Republic

PubMed Central

Kamgang, Basile; Ngoagouni, Carine; Manirakiza, Alexandre; Nakouné, Emmanuel; Paupy, Christophe; Kazanji, Mirdad

2013-01-01

The invasive Asian tiger mosquito Aedes albopictus (Diptera: Culicidae) was first reported in central Africa in 2000, in Cameroon, with the indigenous mosquito species Ae. aegypti (Diptera: Culicidae). Today, this invasive species is present in almost all countries of the region, including the Central African Republic (CAR), where it was first recorded in 2009. As invasive species of mosquitoes can affect the distribution of native species, resulting in new patterns of vectors and concomitant risk for disease, we undertook a comparative study early and late in the wet season in the capital and the main cities of CAR to document infestation and the ecological preferences of the two species. In addition, we determined the probable geographical origin of invasive populations of Ae. albopictus with two mitochondrial DNA genes, COI and ND5. Analysis revealed that Ae. aegypti was more abundant earlier in the wet season and Ae. albopictus in the late wet season. Used tyres were the most heavily colonized productive larval habitats for both species in both seasons. The invasive species Ae. albopictus predominated over the resident species at all sites in which the two species were sympatric. Mitochondrial DNA analysis revealed broad low genetic diversity, confirming recent introduction of Ae. albopictus in CAR. Phylogeographical analysis based on COI polymorphism indicated that the Ae. albopictus haplotype in the CAR population segregated into two lineages, suggesting multiple sources of Ae. albopictus. These data may have important implications for vector control strategies in central Africa. PMID:24349596

Economic impact of ecosystem services provided by ecologically sustainable roadside right of way vegetation management practices.

DOT National Transportation Integrated Search

2014-03-01

The economic value of runoff prevention, carbon sequestration, pollination and other insect services, air quality, : invasive species resistance, and aesthetics was estimated for Floridas State Highway System roadside right-of-way (ROW) ecosystem ...

Advancing capability for bioassessment using DNA metabarcoding: Application to aquatic invasive species monitoring

EPA Science Inventory

Characterizing biological communities by their constituent species is fundamental to biological monitoring and ecological condition assessment. Finding and identifying rare species is a long-standing challenge for monitoring programs. Nevertheless, conducting surveys that can des...