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Sample records for coast forest fragments

  1. Global-scale patterns of forest fragmentation

    USGS Publications Warehouse

    Riitters, K.; Wickham, J.; O'Neill, R.; Jones, B.; Smith, E.

    2000-01-01

    We report an analysis of forest fragmentation based on 1-km resolution land-cover maps for the globe. Measurements in analysis windows from 81 km 2 (9 ?? 9 pixels, "small" scale) to 59,049 km 2 (243 ?? 243 pixels, "large" scale) were used to characterize the fragmentation around each forested pixel. We identified six categories of fragmentation (interior, perforated, edge, transitional, patch, and undetermined) from the amount of forest and its occurrence as adjacent forest pixels. Interior forest exists only at relatively small scales; at larger scales, forests are dominated by edge and patch conditions. At the smallest scale, there were significant differences in fragmentation among continents; within continents, there were significant differences among individual forest types. Tropical rain forest fragmentation was most severe in North America and least severe in Europe - Asia. Forest types with a high percentage of perforated conditions were mainly in North America (five types) and Europe - Asia (four types), in both temperate and subtropical regions. Transitional and patch conditions were most common in 11 forest types, of which only a few would be considered as "naturally patchy" (e.g., dry woodland). The five forest types with the highest percentage of interior conditions were in North America; in decreasing order, they were cool rain forest, coniferous, conifer boreal, cool mixed, and cool broadleaf. Copyright ?? 2000 by The Resilience Alliance.

  2. Global Forest Area Trends Underestimate Threats from Forest Fragmentation

    EPA Science Inventory

    Forest loss and fragmentation of the remainder threaten the ecological attributes and functions which depend upon forests1. Forest interior area is particularly valued because it is relatively remote from human influence2, 3, 4, 5. Recent global assessments report declines in t...

  3. Effect of forest fragmentation on bird populations

    USGS Publications Warehouse

    Robbins, C.S.

    1979-01-01

    Many of the insectivorous songbird species that winter in the tropics are dependent on large unbroken tracts of forest during the breeding season. These species are disappearing from localities where forests are becoming fragmented. By long-range planning, managers can prevent local extinctions of these area-sensitive birds through use of such techniques as management in large units, retention of connecting corridors, and prevention of excessive isolation of forest fragments. Edge conditions can be provided, where appropriate to meet the needs of upland game species.

  4. Forest fragmentation and Lyme disease

    EPA Science Inventory

    Lyme disease is the most commonly reported vectorborne disease in the United States. It is associated with human exposure to infected Ixodes ticks which exist even in degraded forest and herbaceous habitat. We provide an overview of the epidemiology, ecology and landscape charact...

  5. Forest fragmentation and its effects on birds

    USGS Publications Warehouse

    Robbins, C.S.; Johnson, James E.

    1988-01-01

    Fragmentation of forest land, whether by suburban development, highways, transmission lines, or poorly planned cutting regimes, seriously affects reproduction by the large numbers of obligate forest interior birds. Many of our warblers, vireos, thrushes, tanagers, and flycatchers are highly migratory insectivorous birds that spend more than half the year in the neotropics, but migrate north to the United States and Canada to rear their young. These tropical visitors are especially vulnerable to predation and cowbird parasitism and are unable to maintain their populations within 100-200 m of forest edge. Habitats for these declining species can be provided by managing forest lands in large blocks so as to maintain at all times extensive contiguous areas of successional stages as well as of mature forest. Avoiding scattered small cuts will also help by reducing edge, road construction, and other disturbance.

  6. LOCALIZING NATIONAL FRAGMENTATION STATISTICS WITH FOREST TYPE MAPS

    EPA Science Inventory

    Fragmmentation of forest types is an indicator of biodiversity in the Montreal Process, but the available national data permit assessment of only overall forestland fragmentation, not forest type fragmentation. Here we illustrate how to localize national statistics from the 2003...

  7. Marine West Coast Forests, Chapter 9

    USGS Publications Warehouse

    Perakis, Steven S.; Geiser, Linda H.; Lilleskov, Erik A.; Pardo, Linda H.; Robin-Abbott, Molly J.; Driscoll, Charles T.

    2011-01-01

    Human activities have greatly increased nitrogen emissions and deposition across large areas of Earth. Although nitrogen is an essential nutrient for plant growth, too much nitrogen in excess of critical loads leads to losses of biodiversity, soil and stream acidification, nutrient imbalances, and other deleterious effects. In a new report quantifying critical loads of nitrogen deposition across the United States, USGS scientist Steve Perakis and co-authors provided a chapter about responses of marine west coast forests. Much of this region is understudied with respect to nitrogen deposition, and in this chapter the authors identify known adverse effects and estimate critical loads of nitrogen deposition for western Oregon and Washington and southeast Alaska forests. Perakis also contributed to the synthesis chapter, which includes background, objectives, advantages and uncertainties of critical loads, an overview of critical loads across U.S. ecoregions, and other topics.

  8. EXAMINING MULTI-SCALE CHANGES IN FOREST FRAGMENTATION

    EPA Science Inventory

    Forest fragmentation is a key measurement of forest condition. In comparison to the Chesapeake Bay region, dominant forest loss in New Jersey was less sensitive to forest loss, which may be attributable the protected status of the New Jersey Pine Barrens.

  9. Fragmentation of Forest Communities in the Eastern United States

    EPA Science Inventory

    Forest fragmentation threatens the sustainability of forest communities and therefore the beta diversity of forestland in the eastern United States. We combined forest inventory data with land cover data to compare 70 forest communities in terms of the amount and ownership of int...

  10. Characterizing the forest fragmentation of Canada's national parks.

    PubMed

    Soverel, Nicholas O; Coops, Nicholas C; White, Joanne C; Wulder, Michael A

    2010-05-01

    Characterizing the amount and configuration of forests can provide insights into habitat quality, biodiversity, and land use. The establishment of protected areas can be a mechanism for maintaining large, contiguous areas of forests, and the loss and fragmentation of forest habitat is a potential threat to Canada's national park system. Using the Earth Observation for Sustainable Development of Forests (EOSD) land cover product (EOSD LC 2000), we characterize the circa 2000 forest patterns in 26 of Canada's national parks and compare these to forest patterns in the ecological units surrounding these parks, referred to as the greater park ecosystem (GPE). Five landscape pattern metrics were analyzed: number of forest patches, mean forest patch size (hectare), standard deviation of forest patch size (hectare), mean forest patch perimeter-to-area ratio (meters per hectare), and edge density of forest patches (meters per hectare). An assumption is often made that forests within park boundaries are less fragmented than the surrounding GPE, as indicated by fewer forest patches, a larger mean forest patch size, less variability in forest patch size, a lower perimeter-to-area ratio, and lower forest edge density. Of the 26 national parks we analyzed, 58% had significantly fewer patches, 46% had a significantly larger mean forest patch size (23% were not significantly different), and 46% had a significantly smaller standard deviation of forest patch size (31% were not significantly different), relative to their GPEs. For forest patch perimeter-to-area ratio and forest edge density, equal proportions of parks had values that were significantly larger or smaller than their respective GPEs and no clear trend emerged. In summary, all the national parks we analyzed, with the exception of the Georgian Bay Islands, were found to be significantly different from their corresponding GPE for at least one of the five metrics assessed, and 50% of the 26 parks were significantly

  11. Effect of fragmentation on the Costa Rican dry forest avifauna.

    PubMed

    Barrantes, Gilbert; Ocampo, Diego; Ramírez-Fernández, José D; Fuchs, Eric J

    2016-01-01

    Deforestation and changes in land use have reduced the tropical dry forest to isolated forest patches in northwestern Costa Rica. We examined the effect of patch area and length of the dry season on nestedness of the entire avian community, forest fragment assemblages, and species occupancy across fragments for the entire native avifauna, and for a subset of forest dependent species. Species richness was independent of both fragment area and distance between fragments. Similarity in bird community composition between patches was related to habitat structure; fragments with similar forest structure have more similar avian assemblages. Size of forest patches influenced nestedness of the bird community and species occupancy, but not nestedness of assemblages across patches in northwestern Costa Rican avifauna. Forest dependent species (species that require large tracts of mature forest) and assemblages of these species were nested within patches ordered by a gradient of seasonality, and only occupancy of species was nested by area of patches. Thus, forest patches with a shorter dry season include more forest dependent species.

  12. Effect of fragmentation on the Costa Rican dry forest avifauna

    PubMed Central

    Barrantes, Gilbert; Ocampo, Diego; Ramírez-Fernández, José D.

    2016-01-01

    Deforestation and changes in land use have reduced the tropical dry forest to isolated forest patches in northwestern Costa Rica. We examined the effect of patch area and length of the dry season on nestedness of the entire avian community, forest fragment assemblages, and species occupancy across fragments for the entire native avifauna, and for a subset of forest dependent species. Species richness was independent of both fragment area and distance between fragments. Similarity in bird community composition between patches was related to habitat structure; fragments with similar forest structure have more similar avian assemblages. Size of forest patches influenced nestedness of the bird community and species occupancy, but not nestedness of assemblages across patches in northwestern Costa Rican avifauna. Forest dependent species (species that require large tracts of mature forest) and assemblages of these species were nested within patches ordered by a gradient of seasonality, and only occupancy of species was nested by area of patches. Thus, forest patches with a shorter dry season include more forest dependent species. PMID:27672498

  13. Evaluating differences in forest fragmentation and restoration between western natural forests and southeastern plantation forests in the United States.

    PubMed

    Ren, Xinyu; Lv, Yingying; Li, Mingshi

    2017-03-01

    Changes in forest ecosystem structure and functions are considered some of the research issues in landscape ecology. In this study, advancing Forman's theory, we considered five spatially explicit processes associated with fragmentation, including perforation, dissection, subdivision, shrinkage, and attrition, and two processes associated with restoration, i.e., increment and expansion processes. Following this theory, a forest fragmentation and restoration process model that can detect the spatially explicit processes and ecological consequences of forest landscape change was developed and tested in the current analysis. Using the National Land Cover Databases (2001, 2006 and 2011), the forest fragmentation and restoration process model was applied to US western natural forests and southeastern plantation forests to quantify and classify forest patch losses into one of the four fragmentation processes (the dissection process was merged into the subdivision process) and to classify the newly gained forest patches based on the two restoration processes. At the same time, the spatio-temporal differences in fragmentation and restoration patterns and trends between natural forests and plantations were further compared. Then, through overlaying the forest fragmentation/restoration processes maps with targeting year land cover data and land ownership vectors, the results from forest fragmentation and the contributors to forest restoration in federal and nonfederal lands were identified. Results showed that, in natural forests, the forest change patches concentrated around the urban/forest, cultivated/forest, and shrubland/forest interfaces, while the patterns of plantation change patches were scattered sparsely and irregularly. The shrinkage process was the most common type in forest fragmentation, and the average size was the smallest. Expansion, the most common restoration process, was observed in both natural forests and plantations and often occurred around the

  14. DISTRIBUTION AND CAUSES OF GLOBAL FOREST FRAGMENTATION

    EPA Science Inventory

    Because human land uses tend to expand over time, forests that share a high proportion of their borders with anthropogenic uses are at higher risk of further degradation than forests that share a high proportion of their borders with non-forest, natural land cover (e.g. wetland)....

  15. Forest-climate interactions in fragmented tropical landscapes.

    PubMed

    Laurance, William F

    2004-03-29

    In the tropics, habitat fragmentation alters forest-climate interactions in diverse ways. On a local scale (less than 1 km), elevated desiccation and wind disturbance near fragment margins lead to sharply increased tree mortality, thus altering canopy-gap dynamics, plant community composition, biomass dynamics and carbon storage. Fragmented forests are also highly vulnerable to edge-related fires, especially in regions with periodic droughts or strong dry seasons. At landscape to regional scales (10-1000 km), habitat fragmentation may have complex effects on forest-climate interactions, with important consequences for atmospheric circulation, water cycling and precipitation. Positive feedbacks among deforestation, regional climate change and fire could pose a serious threat for some tropical forests, but the details of such interactions are poorly understood.

  16. Forest-climate interactions in fragmented tropical landscapes.

    PubMed Central

    Laurance, William F

    2004-01-01

    In the tropics, habitat fragmentation alters forest-climate interactions in diverse ways. On a local scale (less than 1 km), elevated desiccation and wind disturbance near fragment margins lead to sharply increased tree mortality, thus altering canopy-gap dynamics, plant community composition, biomass dynamics and carbon storage. Fragmented forests are also highly vulnerable to edge-related fires, especially in regions with periodic droughts or strong dry seasons. At landscape to regional scales (10-1000 km), habitat fragmentation may have complex effects on forest-climate interactions, with important consequences for atmospheric circulation, water cycling and precipitation. Positive feedbacks among deforestation, regional climate change and fire could pose a serious threat for some tropical forests, but the details of such interactions are poorly understood. PMID:15212089

  17. Rain forest fragmentation and the proliferation of successional trees.

    PubMed

    Laurance, William F; Nascimento, Henrique E M; Laurance, Susan G; Andrade, Ana C; Fearnside, Philip M; Ribeiro, José E L; Capretz, Robson L

    2006-02-01

    The effects of habitat fragmentation on diverse tropical tree communities are poorly understood. Over a 20-year period we monitored the density of 52 tree species in nine predominantly successional genera (Annona, Bellucia, Cecropia, Croton, Goupia, Jacaranda, Miconia, Pourouma, Vismia) in fragmented and continuous Amazonian forests. We also evaluated the relative importance of soil, topographic, forest dynamic, and landscape variables in explaining the abundance and species composition of successional trees. Data were collected within 66 permanent 1-ha plots within a large (approximately 1000 km2) experimental landscape, with forest fragments ranging from 1 to 100 ha in area. Prior to forest fragmentation, successional trees were uncommon, typically comprising 2-3% of all trees (> or =10 cm diameter at breast height [1.3 m above the ground surface]) in each plot. Following fragmentation, the density and basal area of successional trees increased rapidly. By 13-17 years after fragmentation, successional trees had tripled in abundance in fragment and edge plots and constituted more than a quarter of all trees in some plots. Fragment age had strong, positive effects on the density and basal area of successional trees, with no indication of a plateau in these variables, suggesting that successional species could become even more abundant in fragments over time. Nonetheless, the 52 species differed greatly in their responses to fragmentation and forest edges. Some disturbance-favoring pioneers (e.g., Cecropia sciadophylla, Vismia guianensis, V. amazonica, V. bemerguii, Miconia cf. crassinervia) increased by >1000% in density on edge plots, whereas over a third (19 of 52) of all species remained constant or declined in numbers. Species responses to fragmentation were effectively predicted by their median growth rate in nearby intact forest, suggesting that faster-growing species have a strong advantage in forest fragments. An ordination analysis revealed three main

  18. Fragmented forest in tropical landscape--the case of the state of Selangor, Malaysia.

    PubMed

    Abdullah, Saiful Arif

    2003-03-01

    This paper presents the pattern and changes of fragmented forest in relation with changes of total forest cover in the state of Selangor in three decades. In this study, inventoried forest cover maps of Selangor in 1971/1972, 1981/1982 and 1991/1992 produced by the Forestry Department of Peninsular Malaysia were digitized to examine the changes in area and number of fragmented forest. Results showed that in 1971/1972, 16 fragmented forests were identified in Selangor. All fragmented forests were identified as dipterocarp forest. A decade later the number of fragmented forests increased by approximately 44% (23). Of the 23 fragmented forests, two were peat swamp forests whereas the remaining were dipterocarp forests. In 1991/1992 the number of fragmented forests (12) was reduced by 47.8%. Two of the fragmented forests were identified as peat swamp forest, seven dipterocarp forest and the other three was mixed of dipterocarp forests and plantation forests. Fragmentation of both dipterocarp and peat swamp forests occurred profoundly during the period between 1971/1972 and 1981/1982, which consequently increased the number of fragmented forests compared with before the period of 1971/1972 where fragmentation happened only at dipterocarp forests. However, many fragmented forests vanished between the 1981/1982 and 1991/1992 periods.

  19. Long-term carbon loss in fragmented Neotropical forests.

    PubMed

    Pütz, Sandro; Groeneveld, Jürgen; Henle, Klaus; Knogge, Christoph; Martensen, Alexandre Camargo; Metz, Markus; Metzger, Jean Paul; Ribeiro, Milton Cezar; de Paula, Mateus Dantas; Huth, Andreas

    2014-10-07

    Tropical forests play an important role in the global carbon cycle, as they store a large amount of carbon (C). Tropical forest deforestation has been identified as a major source of CO2 emissions, though biomass loss due to fragmentation--the creation of additional forest edges--has been largely overlooked as an additional CO2 source. Here, through the combination of remote sensing and knowledge on ecological processes, we present long-term carbon loss estimates due to fragmentation of Neotropical forests: within 10 years the Brazilian Atlantic Forest has lost 69 (±14) Tg C, and the Amazon 599 (±120) Tg C due to fragmentation alone. For all tropical forests, we estimate emissions up to 0.2 Pg C y(-1) or 9 to 24% of the annual global C loss due to deforestation. In conclusion, tropical forest fragmentation increases carbon loss and should be accounted for when attempting to understand the role of vegetation in the global carbon balance.

  20. Forest structure and downed woody debris in boreal, temperate, and tropical forest fragments.

    PubMed

    Gould, William A; González, Grizelle; Hudak, Andrew T; Hollingsworth, Teresa Nettleton; Hollingsworth, Jamie

    2008-12-01

    Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve our ability to manage forest fuels and predict fire behavior. In this study we assessed forest fuel characteristics in stands of differing moisture, i.e., dry and moist forests, structure, i.e., open canopy (typically younger) vs. closed canopy (typically older) stands, and size, i.e., small (10-14 ha), medium (33 to 60 ha), and large (100-240 ha) along a climatic gradient of boreal, temperate, and tropical forests. We measured duff, litter, fine and coarse woody debris, standing dead, and live biomass in a series of plots along a transect from outside the forest edge to the fragment interior. The goal was to determine how forest structure and fuel characteristics varied along this transect and whether this variation differed with temperature, moisture, structure, and fragment size. We found nonlinear relationships of coarse woody debris, fine woody debris, standing dead and live tree biomass with mean annual median temperature. Biomass for these variables was greatest in temperate sites. Forest floor fuels (duff and litter) had a linear relationship with temperature and biomass was greatest in boreal sites. In a five-way multivariate analysis of variance we found that temperature, moisture, and age/structure had significant effects on forest floor fuels, downed woody debris, and live tree biomass. Fragment size had an effect on forest floor fuels and live tree biomass. Distance from forest edge had significant effects for only a few subgroups sampled. With some exceptions edges were not distinguishable from interiors in terms of fuels.

  1. Biogeographical and taxonomic biases in tropical forest fragmentation research.

    PubMed

    Deikumah, Justus P; McAlpine, Clive A; Maron, Martine

    2014-12-01

    Despite several decades of research on the effects of fragmentation and habitat change on biodiversity, there remain strong biases in the geographical regions and taxonomic species studied. The knowledge gaps resulting from these biases are of particular concern if the forests most threatened with modification are also those for which the effects of such change are most poorly understood. To quantify the nature and magnitude of such biases, we conducted a systematic review of the published literature on forest fragmentation in the tropics for the period 1980-2012. Studies included focused on any type of response of single species, communities, or assemblages of any taxonomic group to tropical forest fragmentation and on fragmentation-related changes to forests. Of the 853 studies we found in the SCOPUS database, 64% were conducted in the Neotropics, 13% in Asia, 10% in the Afrotropics, and 5% in Australasia. Thus, although the Afrotropics is subject to the highest rates of deforestation globally, it was the most disproportionately poorly studied biome. Significant taxonomic biases were identified. Of the taxonomic groups considered, herpetofauna was the least studied in the tropics, particularly in Africa. Research examining patterns of species distribution was by far the most common type (72%), and work focused on ecological processes (28%) was rare in all biomes, but particularly in the Afrotropics and for fauna. We suggest research efforts be directed toward less-studied biogeographic regions, particularly where the threat of forest fragmentation continues to be high. Increased research investment in the Afrotropics will be important to build knowledge of threats and inform responses in a region where almost no efforts to restore its fragmented landscapes have yet begun and forest protection is arguably most tenuous.

  2. Habitat fragmentation lowers survival of a tropical forest bird.

    PubMed

    Ruiz-Gutiérrez, Viviana; Gavin, Thomas A; Dhondt, André A

    2008-06-01

    Population ecology research has long been focused on linking environmental features with the viability of populations. The majority of this work has largely been carried out in temperate systems and, until recently, has examined the effects of habitat fragmentation on survival. In contrast, we looked at the effect of forest fragmentation on apparent survival of individuals of the White-ruffed Manakin (Corapipo altera) in southern Costa Rica. Survival and recapture rates were estimated using mark-recapture analyses, based on capture histories from 1993 to 2006. We sampled four forest patches ranging in size from 0.9 to 25 ha, and four sites in the larger 227-ha Las Cruces Biological Station Forest Reserve (LCBSFR). We found a significant difference in annual adult apparent survival rates for individuals marked and recaptured in forest fragments vs. individuals marked and recaptured in the larger LCBSFR. Contrary to our expectation, survival and recapture probabilities did not differ between male and female manakins. Also, there was no support for the existence of annual variation in survival within each study site. Our results suggest that forest fragmentation is likely having an effect on population dynamics for the White-ruffed Manakin in this landscape. Therefore, populations that appear to be persisting in fragmented landscapes might still be at risk of local extinction, and conservation action for tropical birds should be aimed at identifying and reducing sources of adult mortality. Future studies in fragmentation effects on reproductive success and survival, across broad geographical scales, will be needed before it is possible to achieve a clear understanding of the effects of habitat fragmentation on populations for both tropical and temperate regions.

  3. PATTERNS OF NITRATE LOSSES FROM FORESTED BASINS IN THE OREGON COAST RANGE

    EPA Science Inventory

    Numerous factors may control losses of dissolved nutrients from forested basins in the Oregon Coast Range. Potentially important factors include forest composition, stand age, forest management, grazing, agriculture, sewage inputs and bedrock types, as well as others perhaps not...

  4. Artificial nest experiments in a fragmented neotropical cloud forest

    USGS Publications Warehouse

    Trujillo, G.; Ahumada, J.A.

    2005-01-01

    We conducted artificial nest experiments in a Neotropical montane forest in the eastern Andes, Colombia, in order to test the effect of placing the nests in forest fragments or continuous forests, at two nest heights and for two different climatic seasons. Predation was not consistently different between nests placed in fragments and controls. However, we found that nests on the ground had a higher daily probability of being predated than nests in the understory. Also, daily nest mortality rate (DNM) was higher in the wet season than in the dry season. Most of the predated nests were attributed to mammals (56%), and predation occurred mostly on the ground (78%). Our estimates of DNM are quite low (= 0.023) and similar to another Neotropical montane forest and other Neotropical sites. Comparisons of DNM between Neotropical and temperate sites suggests that predation rates are similar. Our results suggest that fragmentation may not have a large negative impact in nest predation for bird populations breeding in fragments compared to other sites in tropical and temperate regions. ?? The Neotropical Ornithological Society.

  5. TEMPORAL CHANGE IN FOREST FRAGMENTATION AT MULTIPLE SCALES

    EPA Science Inventory

    Previous studies of temporal changes in fragmentation have focused almost exclusively on patch and edge statistics, which might not detect changes in the spatial scale at which forest occurs in or dominates the landscape. We used temporal land-cover data for the Chesapeake Bay r...

  6. Effects of natural forest fragmentation on a Hawaiian spider community

    USGS Publications Warehouse

    Vandergast, Amy; Gillespie, Rosemary G.

    2004-01-01

    The kipuka system, a network of forest fragments surrounded by lava flows on the island of Hawaii, offers an opportunity to study the natural, long-term fragmentation of a native ecosystem. We examined the impacts of habitat edges upon the community structure of nocturnally active native spiders, primarily in the genus Tetragnatha. We measured plant and spider species distributions across the edges of four small fragments and one large continuously forested area that were surrounded by a lava flow in 1855. Results indicated that an ???20 m edge ecotone surrounds core forest habitat. Spider community structure changed across the edge, with a decrease in total species richness and diversity at the forest/lava boundary, and a change in the dominant taxon from native Tetragnatha (Tetragnathidae) to native Cyclosa (Araneidae). Severe habitat restrictions were found for some spider species. In addition, nearly all of the spiders captured were endemic species, and the few introduced species were limited to the younger and more open lava flows. Our results suggest that species responses to edges can vary, and that core habitat specialists may decline in fragmented conditions.

  7. Birds transport nutrients to fragmented forests in an urban landscape.

    PubMed

    Fujita, Motoko; Koike, Fumito

    2007-04-01

    The influence of urbanization on nutrient cycling is vaguely known. Here we document that birds, especially those increasing in urban areas (such as crows, Corvus macrorhynchos and C. corone), affect nutrient cycles. Using fecal traps, we measured phosphorus (P) and nitrogen (N) input from the excrement of birds in fragmented forests in an urban landscape. Sources of avian feces were examined on the basis of carbon (C), N, and P percentages and stable isotopes of delta15N and delta13C. Nitrogen and P input was aggregated in the urban landscape, being especially high at the forest where crows roosted during winter. The annual P input due to bird droppings (range 0.068-0.460 kg x ha(-1) x yr(-1); mean 0.167 kg x ha(-1) x yr(-1)) was 12.4% of the total of other pathways in typical forests and 52.9% in the evergreen forest where crows roosted. The annual N input due to bird droppings (range 0.44-3.49 kg x ha(-1) x yr(-1); mean 1.15 kg x ha(-1) x yr(-1)) was 5.2% of the total of other pathways in typical forests and 27.0% in the evergreen forest used by roosting crows. Expected sources of nutrients in feces included insects in the breeding season, fruits in autumn, and mammals and birds in winter. Stable isotopes suggested that the source of nutrients in forests used by roosting crows was from outside the forest. Therefore, birds played a significant role as transporters of nutrients from garbage (including fish, livestock, and/or C4 plants such as corn, with high delta15N and delta13C) in residential and business areas to fragmented evergreen forests, especially near their winter roosts.

  8. Forests on thawing permafrost: fragmentation, edge effects, and net forest loss.

    PubMed

    Baltzer, Jennifer L; Veness, Tyler; Chasmer, Laura E; Sniderhan, Anastasia E; Quinton, William L

    2014-03-01

    Much of the world's boreal forest occurs on permafrost (perennially cryotic ground). As such, changes in permafrost conditions have implications for forest function and, within the zone of discontinuous permafrost (30-80% permafrost in areal extent), distribution. Here, forested peat plateaus underlain by permafrost are elevated above the surrounding permafrost-free wetlands; as permafrost thaws, ground surface subsidence leads to waterlogging at forest margins. Within the North American subarctic, recent warming has produced rapid, widespread permafrost thaw and corresponding forest loss. Although permafrost thaw-induced forest loss provides a natural analogue to deforestation occurring in more southerly locations, we know little about how fragmentation relates to subsequent permafrost thaw and forest loss or the role of changing conditions at the edges of forested plateaus. We address these knowledge gaps by (i) examining the relationship of forest loss to the degree of fragmentation in a boreal peatland in the Northwest Territories, Canada; and (ii) quantifying associated biotic and abiotic changes occurring across forest-wetland transitions and extending into the forested plateaus (i.e., edge effects). We demonstrate that the rate of forest loss correlates positively with the degree of fragmentation as quantified by perimeter to area ratio of peat plateaus (edge : area). Changes in depth of seasonal thaw, soil moisture, and effective leaf area index (LAIe ) penetrated the plateau forests by 3-15 m. Water uptake by trees was sevenfold greater in the plateau interior than at the edges with direct implications for tree radial growth. A negative relationship existed between LAIe and soil moisture, suggesting that changes in vegetation physiological function may contribute to changing edge conditions while simultaneously being affected by these changes. Enhancing our understanding of mechanisms contributing to differential rates of permafrost thaw and associated

  9. Avian nest success in midwestern forests fragmented by agriculture

    USGS Publications Warehouse

    Knutson, M.G.; Friberg, M.A.; Niemi, G.J.; Newton, W.E.

    2004-01-01

    Knutson et al. (2004) report the results of an avian nest success study conducted to investigate how forest-bird nest success varied by nest location and type as well as by landscape context from 1996 to 1998 in an agricultural region of southwestern Minnesota, and southwestern Wisconsin, and northeastern Iowa. The authors found an overall Mayfield adjusted nest success of 48%, 82% for cavity-nesting species, and 42% for cup-nesting species. Common species varied from 23% for American Redstart (Setophaga ruticilla) to 43% for the Eastern Wood-Pewee (Contopus virens). Nest success was lowest for open-cup nesters, species that reject Brown-headed Cowbird (Molothrus ater) eggs, species that next near forest edges, and Neotropical migrants. These tendencies were consistent across the years of the study. Assessments of nest success considering surrounding landscape metrics indicated that forest area may not be a strong indicator of nest success in landscapes where all the available forests are fragmented.

  10. Rates of species loss from Amazonian forest fragments

    PubMed Central

    Ferraz, Gonçalo; Russell, Gareth J.; Stouffer, Philip C.; Bierregaard, Richard O.; Pimm, Stuart L.; Lovejoy, Thomas E.

    2003-01-01

    In the face of worldwide habitat fragmentation, managers need to devise a time frame for action. We ask how fast do understory bird species disappear from experimentally isolated plots in the Biological Dynamics of Forest Fragments Project, central Amazon, Brazil. Our data consist of mist-net records obtained over a period of 13 years in 11 sites of 1, 10, and 100 hectares. The numbers of captures per species per unit time, analyzed under different simplifying assumptions, reveal a set of species-loss curves. From those declining numbers, we derive a scaling rule for the time it takes to lose half the species in a fragment as a function of its area. A 10-fold decrease in the rate of species loss requires a 1,000-fold increase in area. Fragments of 100 hectares lose one half of their species in <15 years, too short a time for implementing conservation measures. PMID:14614134

  11. Chimpanzee seed dispersal in a montane forest fragment in Rwanda.

    PubMed

    Chancellor, Rebecca L; Rundus, Aaron S; Nyandwi, Sylvain

    2017-03-01

    Primate seed dispersal plays an important role in forest regeneration. It may be particularly important to anthropogenically disturbed habitats such as forest fragments. However, few studies have examined primate seed dispersal in these types of environments. Chimpanzees (Pan troglodytes) are frugivorous and large-bodied, and are therefore able to disperse both large and small seeds, making them an important seed dispersal species. We examined chimpanzee seed dispersal in Gishwati forest, a 14 km(2) montane rainforest fragment in Rwanda. We systematically collected ≤24-hr-old fecal samples and counted the number of seeds of each fruit species. We also recorded observations of seeds found in wadges. We found that chimpanzees dispersed at least 18 fruit species in 14 families in their feces. Ninety-five percent of feces had seeds, the most common of which were Ficus spp., Myrianthus holstii, and Maesa lanceolata. We estimated that the Gishwati chimpanzee community with a density of 1.7 individuals per km(2) dispersed an average of 592 (>2 mm) seeds km(-2)  day(-1) . We also found that chimpanzees dispersed the seeds of at least two fruit species, Ficus spp. and Chrysophyllum gorungosanum, in their wadges. In addition, 17% of the tree species recorded in our vegetation plots were chimpanzee-dispersed. This study emphasizes the importance of chimpanzees as large seed dispersers in regenerating forest fragments.

  12. [Ants: species-area relationship in tropical dry forest fragments].

    PubMed

    Lozano-Zambrano, Fabio H; Ulloa-Chacón, Patricia; Armbrecht, Inge

    2009-01-01

    We analyzed the effect of fragmentation on ant species-area and specimen frequency-area relationships in nine patches of tropical dry forest in the middle Cauca river basin in Colombia. Species richness and specimen relative frequency of ants were positively correlated with area, whereas no significant correlation was found between species richness and the degree of isolation calculated for the forest patches. As the fragmentation affects different functional groups in different ways, we analyzed the species-area relationship for separate functional groups of ants. According to the habitat requirements we found that the species richness increased faster as area increased for ants inhabiting decomposing wood, followed by ants associated with trees, while species richness of ants living under dead leaves did not correlate with area. According to the food preference, species richness was positively correlated with area for the army ant group, while no significant correlation was found for solitary hunters or for leaf-cutting ants. Ant species richness and specimen density were calculated from equal size samples and examined in relation to the habitat area. An inverse correlation was found only for specimen density, the opposite of what was expected. To our knowledge this is one of the first studies showing differential responses of functional groups of ants to habitat loss. Moreover, it emphasizes the conservation value of small forest fragments for ants in a tropical dry forest.

  13. Forest fragmentation and bird community dynamics: inference at regional scales

    USGS Publications Warehouse

    Boulinier, T.; Nichols, J.D.; Hines, J.E.; Sauer, J.R.; Flather, C.H.; Pollock, K.H.

    2001-01-01

    With increasing fragmentation of natural areas and a dramatic reduction of forest cover in several parts of the world, quantifying the impact of such changes on species richness and community dynamics has been a subject of much concern. Here, we tested whether in more fragmented landscapes there was a lower number of area-sensitive species and higher local extinction and turnover rates, which could explain higher temporal variability in species richness. To investigate such potential landscape effects at a regional scale, we merged two independent, large-scale monitoring efforts: the North American Breeding Bird Survey (BBS) and the Land Use and Land Cover Classification data from the U.S. Geological Survey. We used methods that accounted for heterogeneity in the probability of detecting species to estimate species richness and temporal changes in the bird communities for BBS routes in three mid-Atlantic U.S. states. Forest breeding bird species were grouped prior to the analyses into area-sensitive and non-area-sensitive species according to previous studies. We tested predictions relating measures of forest structure at one point in time (1974) to species richness at that time and to parameters of forest bird community change over the following 22-yr-period (1975-1996). We used the mean size of forest patches to characterize landscape structure, as high correlations among landscape variables did not allow us to disentangle the relative roles of habitat fragmentation per se and habitat loss. As predicted, together with lower species richness for area-sensitive species on routes surrounded by landscapes with lower mean forest-patch size, we found higher mean year-to-year rates of local extinction. Moreover, the mean year-to-year rates of local turnover (proportion of locally new species) for area-sensitive species were also higher in landscapes with lower mean forest-patch size. These associations were not observed for the non-area-sensitive species group. These

  14. Foraging habits of Alouatta palliata mexicana in three forest fragments.

    PubMed

    Asensio, Norberto; Cristobal-Azkarate, Jurgi; Dias, Pedro Américo D; Vea, Joaquim J; Rodríguez-Luna, Ernesto

    2007-01-01

    The activity patterns and diet of howler monkeys (Alouatta palliata mexicana) were studied in 3 forest fragments in south-eastern Mexico: Playa Escondida (PLA), Agaltepec Island (AGA) and Arroyo Liza (LIZ). Intersite differences offered the opportunity to investigate the foraging adaptations of howler monkeys in response to population and habitat size. In the largest fragment (PLA), the howlers' diet was based on high-quality items (fruit and young leaves). In AGA, where the density of howlers was the highest, their diet was mostly folivorous with a marked exploitation of uncommon food items such as vines, lianas, shrubs and herbs. The dietary differences in AGA were accompanied by more time spent travelling and less time spent resting. Although LIZ was the smallest fragment and had a high howler density, the small group size and the use of energy-minimizing strategies (less time spent travelling and more time spent resting) probably allowed howlers to maintain a frugivorous diet.

  15. [Microclimate edge effects of evergreen broad-leaved forest fragments in Jinyun Mountain: a preliminary study].

    PubMed

    Yan, Min; Zhong, Zhangchen; Qiao, Xiuhong

    2006-01-01

    This paper studied the microclimate of continuous and fragmental evergreen broad-leaved forests in Jinyun Mountain by determining the horizontal gradient distribution of microclimate elements near forest edges. The results showed that there existed clear edge effects of microclimate in every edge of fragmental forests. The distinctions of maximum and minimum air temperature, photosynthetic active radiation, and minimum relative humidity between edge forest and interior forest were higher or greater, while that of maximum ground surface temperature was lower or smaller in dry season than in rain season. The edge effect was the smallest in the biggest fragmental patch, but the greatest in the smallest fragmental patch in interior forest.

  16. Avian nest success in midwestern forests fragmented by agriculture

    USGS Publications Warehouse

    Knutson, M.G.; Niemi, G.J.; Newton, W.E.; Friberg, M.A.

    2004-01-01

    We studied how forest-bird nest success varied by landscape context from 1996 to 1998 in an agricultural region of southeastern Minnesota, southwestern Wisconsin, and northeastern Iowa. Nest success was 48% for all nests, 82% for cavity-nesting species, and 42% for cup-nesting species. Mayfield-adjusted nest success for five common species ranged from 23% for the American Redstart (Setophaga ruticilla) to 43% for the Eastern Wood-Pewee (Contopus virens). Nest success was lowest for open-cup nesters, species that reject Brown-headed Cowbird (Molothrus ater) eggs, species that nest near forest edges, and Neo-tropical migrants. The proportion of forest core area in a 5-km radius around the plot had a weakly negative relationship with daily survival rate of nests for all species pooled and for medium or high canopy nesters, species associated with interior and edge habitats, open-cup nesters, and nests located between 75 and 199 m from an edge. The proportion of forest core area was positively related to daily survival rate only for ground and low nesters. Our findings are in contrast to a number of studies from the eastern United States reporting strong positive associations between forest area and nesting success. Supported models of habitat associations changed with the spatial scale of analysis and included variables not often considered in studies of forest birds, including the proportion of water, shrubs, and grasslands in the landscape. Forest area may not be a strong indicator of nest success in landscapes where all the available forests are fragmented.

  17. Analysis of Edge Effects on Fragmented Forests Using Forest Inventories in Southwestern Amazonia

    NASA Astrophysics Data System (ADS)

    Numata, I.; Silva, S.; Cochrane, M. A.

    2015-12-01

    Deforestation fragments contiguous forests into smaller and smaller pieces, inducing ecological and biological changes in forest ecosystems. Edge effects are spatial and temporal phenomena. The effects of forest fragmentation vary primarily as functions of edge penetration distance, spatial arrangements and time of persistence of forest edges. Across varying penetration distances in a forest edge, numerous changes occur including elevated tree mortality and canopy desiccation, changes in forest structure and species composition, alternation of hydrological and carbon cycles. We analyzed the effects of edge penetration distance and time of persistence of forest edges on forest biophysical characteristics based upon more than thirty 500m transects over highly fragmented forests in Acre, the southwestern Amazon. Spatial variability of tree data (diameter at breast height - DBH, above ground biomass, tree density, species composition and population) was measured along a penetration distance of 500m from forest edges. Different edge age classes (1-5yr, 6-10yr, > 10yr) and edge penetration distances were identified based upon a Landsat time-series analysis. The number of individual plants with DBH > 10cm tends to be greater near edge (largest in the first 100m), while larger biomass amounts are found at > 300m distance. The impact of penetration distance on biomass, however, is not statistically significant. In terms of the distribution of DBHs, while smaller trees with DBH <=20cm account for 70% of all trees, larger DBH trees tend to increase after 300m penetration distance. The effect of edge persistence period (edge age) is not significant for both the number of individual plants as well as the biomass, however it is more pronounced on secondary species' biomass such as Cecrcopia sp and bamboo, which increase as edges persist longer.

  18. Thermokarst rates intensify due to climate change and forest fragmentation in an Alaskan boreal forest lowland.

    PubMed

    Lara, Mark J; Genet, Hélène; McGuire, Anthony D; Euskirchen, Eugénie S; Zhang, Yujin; Brown, Dana R N; Jorgenson, Mark T; Romanovsky, Vladimir; Breen, Amy; Bolton, William R

    2016-02-01

    Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse-scar bogs, low shrub/scrub, and forests growing on elevated ice-rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5 °C of thawing. Increased permafrost thaw in lowland boreal forests in response to warming may have consequences for the climate system. This study evaluates the trajectories and potential drivers of 60 years of forest change in a landscape subjected to permafrost thaw in unburned dominant forest types (paper birch and black spruce) associated with location on elevated permafrost plateau and across multiple time periods (1949, 1978, 1986, 1998, and 2009) using historical and contemporary aerial and satellite images for change detection. We developed (i) a deterministic statistical model to evaluate the potential climatic controls on forest change using gradient boosting and regression tree analysis, and (ii) a 30 × 30 m land cover map of the Tanana Flats to estimate the potential landscape-level losses of forest area due to thermokarst from 1949 to 2009. Over the 60-year period, we observed a nonlinear loss of birch forests and a relatively continuous gain of spruce forest associated with thermokarst and forest succession, while gradient boosting/regression tree models identify precipitation and forest fragmentation as the primary factors controlling birch and spruce forest change, respectively. Between 1950 and 2009, landscape-level analysis estimates a transition of ~15 km² or ~7% of birch forests to wetlands, where the greatest change followed warm periods. This work highlights that the vulnerability and resilience of

  19. A large-scale forest fragmentation experiment: the Stability of Altered Forest Ecosystems Project.

    PubMed

    Ewers, Robert M; Didham, Raphael K; Fahrig, Lenore; Ferraz, Gonçalo; Hector, Andy; Holt, Robert D; Kapos, Valerie; Reynolds, Glen; Sinun, Waidi; Snaddon, Jake L; Turner, Edgar C

    2011-11-27

    Opportunities to conduct large-scale field experiments are rare, but provide a unique opportunity to reveal the complex processes that operate within natural ecosystems. Here, we review the design of existing, large-scale forest fragmentation experiments. Based on this review, we develop a design for the Stability of Altered Forest Ecosystems (SAFE) Project, a new forest fragmentation experiment to be located in the lowland tropical forests of Borneo (Sabah, Malaysia). The SAFE Project represents an advance on existing experiments in that it: (i) allows discrimination of the effects of landscape-level forest cover from patch-level processes; (ii) is designed to facilitate the unification of a wide range of data types on ecological patterns and processes that operate over a wide range of spatial scales; (iii) has greater replication than existing experiments; (iv) incorporates an experimental manipulation of riparian corridors; and (v) embeds the experimentally fragmented landscape within a wider gradient of land-use intensity than do existing projects. The SAFE Project represents an opportunity for ecologists across disciplines to participate in a large initiative designed to generate a broad understanding of the ecological impacts of tropical forest modification.

  20. A large-scale forest fragmentation experiment: the Stability of Altered Forest Ecosystems Project

    PubMed Central

    Ewers, Robert M.; Didham, Raphael K.; Fahrig, Lenore; Ferraz, Gonçalo; Hector, Andy; Holt, Robert D.; Kapos, Valerie; Reynolds, Glen; Sinun, Waidi; Snaddon, Jake L.; Turner, Edgar C.

    2011-01-01

    Opportunities to conduct large-scale field experiments are rare, but provide a unique opportunity to reveal the complex processes that operate within natural ecosystems. Here, we review the design of existing, large-scale forest fragmentation experiments. Based on this review, we develop a design for the Stability of Altered Forest Ecosystems (SAFE) Project, a new forest fragmentation experiment to be located in the lowland tropical forests of Borneo (Sabah, Malaysia). The SAFE Project represents an advance on existing experiments in that it: (i) allows discrimination of the effects of landscape-level forest cover from patch-level processes; (ii) is designed to facilitate the unification of a wide range of data types on ecological patterns and processes that operate over a wide range of spatial scales; (iii) has greater replication than existing experiments; (iv) incorporates an experimental manipulation of riparian corridors; and (v) embeds the experimentally fragmented landscape within a wider gradient of land-use intensity than do existing projects. The SAFE Project represents an opportunity for ecologists across disciplines to participate in a large initiative designed to generate a broad understanding of the ecological impacts of tropical forest modification. PMID:22006969

  1. Thermokarst Rates Intensify Due to Climate Change and Forest Fragmentation in an Alaskan Boreal Forest Lowland

    NASA Astrophysics Data System (ADS)

    Lara, M. J.; Genet, H.; McGuire, A. D.; Euskirchen, E. S.; Zhang, Y.; Brown, D. N.; Jorgenson, T.; Romanovsky, V. E.; Breen, A. L.; Bolton, W. R.

    2015-12-01

    Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse scar-bogs, low shrub/scrub, and forests growing on elevated ice rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5o C of thawing. Increases in the collapse of lowland boreal forests in response to warming may have consequences for the climate system. This study evaluates the trajectories and potential drivers of 60 years of forest change in a landscape subjected to permafrost thaw in unburned dominant forest types (paper birch and black spruce) associated with location on elevated permafrost plateau and across multiple time periods (1949, 1978, 1986, 1998 and 2009) using historical and contemporary aerial and satellite images for change detection. We developed (i) a deterministic statistical model to evaluate the potential climatic controls on forest change using gradient boosting and regression tree analysis, and (ii) a 30x30 m land cover map of the Tanana Flats to estimate the potential landscape-level losses of forest area due to thermokarst from 1949 to 2009. Over the 60-year period, we observed a nonlinear loss of birch forests and a relatively continuous gain of spruce forest associated with thermokarst and forest succession, respectively. Gradient boosting and regression tree models identify precipitation and forest fragmentation as the primary factors controlling birch and spruce forest change, respectively. Between 1950-2009 landscape-level analysis estimates a transition of ~15 km² of birch forest area to wetlands on the Tanana Flats, where the greatest change followed warm periods. This work highlights the vulnerability of lowland

  2. Tropical forest fragmentation limits pollination of a keystone understory herb.

    PubMed

    Hadley, Adam S; Frey, Sarah J K; Robinson, W Douglas; Kress, W John; Betts, Matthew G

    2014-08-01

    Loss of native vegetation cover is thought to be a major driver of declines in pollination success worldwide. However, it is not well known whether reducing the fragmentation of remaining vegetation can ameliorate these negative effects. We tested the independent effects of composition vs. configuration on the reproductive success of a keystone tropical forest herb (Heliconia tortuosa). To do this we designed a large-scale mensurative experiment that independently varied connected forest-patch size (configuration) and surrounding amount of forest (composition). In each patch, we tested whether pollen tubes, fruit, and seed set were associated with these landscape variables. We also captured hummingbirds as an indication of pollinator availability in a subset of patches according to the same design. We found evidence for an effect of configuration on seed set of H. tortuosa, but not on other aspects of plant reproduction; proportion of seeds produced increased 40% across the gradient in patch size we observed (0.64 to > 1300 ha), independent of the amount of forest in the surrounding landscape at both local and landscape scales. We also found that the availability of pollinators was dependent upon forest configuration; hummingbird capture rates increased three and one-half times across the patch size gradient, independent of forest amount. Finally, pollinator availability was strongly positively correlated with seed set. We hypothesize that the effects of configuration on plant fitness that we observed are due to reduced pollen quality resulting from altered hummingbird availability and/or movement behavior. Our results suggest that prioritizing larger patches of tropical forest may be particularly important for conservation of this species.

  3. Mosquito (Diptera: Culicidae) diversity of a forest-fragment mosaic in the Amazon rain forest.

    PubMed

    Hutchings, Rosa Sá Gomes; Sallum, Maria Anice Mureb; Hutchings, Roger William

    2011-03-01

    To study the impact of Amazonian forest fragmentation on the mosquito fauna, an inventory of Culicidae was conducted in the upland forest research areas of the Biological Dynamics of Forest Fragments Project located 60 km north of Manaus, Amazonas, Brazil. The culicid community was sampled monthly between February 2002 and May 2003. CDC light traps, flight interception traps, manual aspiration, and net sweeping were used to capture adult specimens along the edges and within forest fragments of different sizes (1, 10, and 100 ha), in second-growth areas surrounding the fragments and around camps. We collected 5,204 specimens, distributed in 18 genera and 160 species level taxa. A list of mosquito taxa is presented with 145 species found in the survey, including seven new records for Brazil, 16 new records for the state of Amazonas, along with the 15 morphotypes that probably represent undescribed species. No exotic species [Aedes aegypti (L.) and Aedes albopictus (Skuse)] were found within the sampled areas. Several species collected are potential vectors of Plasmodium causing human malaria and of various arboviruses. The epidemiological and ecological implications of mosquito species found are discussed, and the results are compared with other mosquito inventories from the Amazon region.

  4. Forest fragmentation and risk of giardiasis in New York State.

    PubMed

    Walsh, Michael G

    2013-12-01

    In the United States, giardiasis is endemic in northern and northeastern states, but its ecology and epidemiology remain elusive. The underlying physical landscape may play a role in shaping points of contact between humans, animals, and Giardia cysts. This study examined 11 years of surveillance data in New York State to measure the relationship between forest fragmentation and the incidence of giardiasis. Adjusted Poisson models showed that increasing points of contact between forested land and developed land, as measured by their shared edges [incident rate ratio (IRR) = 1.003; P < 0.001] and by the perimeter length of forested patches (IRR = 1.31; P = 0.01), were associated with higher incidence of giardiasis cases, whereas increasing forest density was associated with a lower incidence (IRR = 0.97; P < 0.001). These associations were independent of both temperature and surface water area. While these results are only suggestive due to the county-level aggregated data, the findings do identify a potentially important signal in the landscape epidemiology of giardiasis and highlight the need for better, more targeted, field studies on individual water sources for household consumption, inter-species contact in ecotones, surface water contamination, and human giardiasis cases.

  5. Effects of pioneer tree species hyperabundance on forest fragments in northeastern Brazil.

    PubMed

    Tabarelli, Marcelo; Aguiar, Antonio V; Girão, Luciana C; Peres, Carlos A; Lopes, Ariadna V

    2010-12-01

    Despite many studies on fragmentation of tropical forests, the extent to which plant and animal communities are altered in small, isolated forest fragments remains obscure if not controversial. We examined the hypothesis that fragmentation alters the relative abundance of tree species with different vegetative and reproductive traits. In a fragmented landscape (670 km(2) ) of the Atlantic Forest of northeastern Brazil, we categorized 4056 trees of 182 species by leafing pattern, reproductive phenology, and morphology of seeds and fruit. We calculated relative abundance of traits in 50 1-ha plots in three types of forest configurations: forest edges, small forest fragments (3.4-83.6 ha), and interior of the largest forest fragment (3500 ha, old growth). Although evergreen species were the most abundant across all configurations, forest edges and small fragments had more deciduous and semideciduous species than interior forest. Edges lacked supra-annual flowering and fruiting species and had more species and stems with drupes and small seeds than small forest fragments and forest interior areas. In an ordination of species similarity and life-history traits, the three types of configurations formed clearly segregated clusters. Furthermore, the differences in the taxonomic and functional (i.e., trait-based) composition of tree assemblages we documented were driven primarily by the higher abundance of pioneer species in the forest edge and small forest fragments. Our work provides strong evidence that long-term transitions in phenology and seed and fruit morphology of tree functional groups are occurring in fragmented tropical forests. Our results also suggest that edge-induced shifts in tree assemblages of tropical forests can be larger than previously documented.

  6. Associations of forest cover, fragment area, and connectivity with neotropical understory bird species richness and abundance.

    PubMed

    Martensen, Alexandre Camargo; Ribeiro, Milton Cezar; Banks-Leite, Cristina; Prado, Paulo Inácio; Metzger, Jean Paul

    2012-12-01

    Theoretical and empirical studies demonstrate that the total amount of forest and the size and connectivity of fragments have nonlinear effects on species survival. We tested how habitat amount and configuration affect understory bird species richness and abundance. We used mist nets (almost 34,000 net hours) to sample birds in 53 Atlantic Forest fragments in southeastern Brazil. Fragments were distributed among 3 10,800-ha landscapes. The remaining forest in these landscapes was below (10% forest cover), similar to (30%), and above (50%) the theoretical fragmentation threshold (approximately 30%) below which the effects of fragmentation should be intensified. Species-richness estimates were significantly higher (F= 3715, p = 0.00) where 50% of the forest remained, which suggests a species occurrence threshold of 30-50% forest, which is higher than usually occurs (<30%). Relations between forest cover and species richness differed depending on species sensitivity to forest conversion and fragmentation. For less sensitive species, species richness decreased as forest cover increased, whereas for highly sensitive species the opposite occurred. For sensitive species, species richness and the amount of forest cover were positively related, particularly when forest cover was 30-50%. Fragment size and connectivity were related to species richness and abundance in all landscapes, not just below the 30% threshold. Where 10% of the forest remained, fragment size was more related to species richness and abundance than connectivity. However, the relation between connectivity and species richness and abundance was stronger where 30% of the landscape was forested. Where 50% of the landscape was forested, fragment size and connectivity were both related to species richness and abundance. Our results demonstrated a rapid loss of species at relatively high levels of forest cover (30-50%). Highly sensitive species were 3-4 times more common above the 30-50% threshold than below it

  7. Massive structural and compositional changes over two decades in forest fragments near Kampala, Uganda

    PubMed Central

    Bulafu, C; Baranga, D; Mucunguzi, P; Telford, R J; Vandvik, V

    2013-01-01

    Private forests harbor considerable biodiversity, however, they are under greater threat than reserved areas, particularly from urbanization, agriculture, and intense exploitation for timber and fuel wood. The extent to which they may act as habitats for biodiversity and how level of protection impacts trends in biodiversity and forest structure over time remain underresearched. We contribute to filling this research gap by resampling a unique data set, a detailed survey from 1990 of 22 forests fragments of different ownership status and level of protection near Kampala, Uganda. Eleven of the 22 fragments were lost over 20 years, and six of the remnants reduced in size. Forest structure and composition also showed dramatic changes, with six of the remnant fragments showing high temporal species turnover. Species richness increased in four of the remaining forests over the resample period. Forest ownership affected the fate of the forests, with higher loss in privately owned forests. Our study demonstrates that ownership affects the fate of forest fragments, with private forests having both higher rates of area loss, and of structural and compositional change within the remaining fragments. Still, the private forests contribute to the total forest area, and they harbor biodiversity including IUCN “vulnerable” and “endangered” species. This indicates the conservation value of the fragments and suggests that they should be taken into account in forest conservation and restoration. PMID:24198941

  8. Thermokarst rates intensify due to climate change and forest fragmentation in an Alaskan boreal forest lowland

    USGS Publications Warehouse

    Lara, M.; Genet, Helene; McGuire, Anthony; Euskirchen, Eugénie S.; Zhang, Yujin; Brown, Dana R. N.; Jorgenson, M.T.; Romanovsky, V.; Breen, Amy L.; Bolton, W.R.

    2016-01-01

    Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse-scar bogs, low shrub/scrub, and forests growing on elevated ice-rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5 °C of thawing. Increased permafrost thaw in lowland boreal forests in response to warming may have consequences for the climate system. This study evaluates the trajectories and potential drivers of 60 years of forest change in a landscape subjected to permafrost thaw in unburned dominant forest types (paper birch and black spruce) associated with location on elevated permafrost plateau and across multiple time periods (1949, 1978, 1986, 1998, and 2009) using historical and contemporary aerial and satellite images for change detection. We developed (i) a deterministic statistical model to evaluate the potential climatic controls on forest change using gradient boosting and regression tree analysis, and (ii) a 30 × 30 m land cover map of the Tanana Flats to estimate the potential landscape-level losses of forest area due to thermokarst from 1949 to 2009. Over the 60-year period, we observed a nonlinear loss of birch forests and a relatively continuous gain of spruce forest associated with thermokarst and forest succession, while gradient boosting/regression tree models identify precipitation and forest fragmentation as the primary factors controlling birch and spruce forest change, respectively. Between 1950 and 2009, landscape-level analysis estimates a transition of ~15 km² or ~7% of birch forests to wetlands, where the greatest change followed warm periods. This work highlights that the vulnerability and resilience of

  9. Understanding the impacts of forest fragmentation in the Southern Appalachian Mountains

    SciTech Connect

    Pearson, S.M.

    1993-06-01

    Southern Appalachian forests are rich in biological diversity. These forests contain many species adapted to conditions ranging from mesic coves to xeric ridges. The major plant communities include wetlands and balds as well as hardwood and coniferous forests. To understand the impacts of habitat fragmentation, the sensitivity of ecosystems, communities, and species to fragmentation must be determined. Recognizing the natural patterns of heterogeneity in these forest and the importance of this heterogeneity to ecological processes will promote our understanding of fragmentation. The impact of a specific forest use (economic development, forest harvesting, recreation) depends on the type of habitat modification.and the spatial extent and pattern of this use. Information on ecological processes, maps of natural communities, and projections about activities that modify forests are needed in order to implement management strategies that will minimize forest fragmentation.

  10. Detecting Fragmentation Extinction Thresholds for Forest Understory Plant Species in Peninsular Spain

    PubMed Central

    Rueda, Marta; Moreno Saiz, Juan Carlos; Morales-Castilla, Ignacio; Albuquerque, Fabio S.; Ferrero, Mila; Rodríguez, Miguel Á.

    2015-01-01

    Ecological theory predicts that fragmentation aggravates the effects of habitat loss, yet empirical results show mixed evidences, which fail to support the theory instead reinforcing the primary importance of habitat loss. Fragmentation hypotheses have received much attention due to their potential implications for biodiversity conservation, however, animal studies have traditionally been their main focus. Here we assess variation in species sensitivity to forest amount and fragmentation and evaluate if fragmentation is related to extinction thresholds in forest understory herbs and ferns. Our expectation was that forest herbs would be more sensitive to fragmentation than ferns due to their lower dispersal capabilities. Using forest cover percentage and the proportion of this percentage occurring in the largest patch within UTM cells of 10-km resolution covering Peninsular Spain, we partitioned the effects of forest amount versus fragmentation and applied logistic regression to model occurrences of 16 species. For nine models showing robustness according to a set of quality criteria we subsequently defined two empirical fragmentation scenarios, minimum and maximum, and quantified species’ sensitivity to forest contraction with no fragmentation, and to fragmentation under constant forest cover. We finally assessed how the extinction threshold of each species (the habitat amount below which it cannot persist) varies under no and maximum fragmentation. Consistent with their preference for forest habitats probability occurrences of all species decreased as forest cover contracted. On average, herbs did not show significant sensitivity to fragmentation whereas ferns were favored. In line with theory, fragmentation yielded higher extinction thresholds for two species. For the remaining species, fragmentation had either positive or non-significant effects. We interpret these differences as reflecting species-specific traits and conclude that although forest amount is of

  11. Detecting fragmentation extinction thresholds for forest understory plant species in peninsular Spain.

    PubMed

    Rueda, Marta; Moreno Saiz, Juan Carlos; Morales-Castilla, Ignacio; Albuquerque, Fabio S; Ferrero, Mila; Rodríguez, Miguel Á

    2015-01-01

    Ecological theory predicts that fragmentation aggravates the effects of habitat loss, yet empirical results show mixed evidences, which fail to support the theory instead reinforcing the primary importance of habitat loss. Fragmentation hypotheses have received much attention due to their potential implications for biodiversity conservation, however, animal studies have traditionally been their main focus. Here we assess variation in species sensitivity to forest amount and fragmentation and evaluate if fragmentation is related to extinction thresholds in forest understory herbs and ferns. Our expectation was that forest herbs would be more sensitive to fragmentation than ferns due to their lower dispersal capabilities. Using forest cover percentage and the proportion of this percentage occurring in the largest patch within UTM cells of 10-km resolution covering Peninsular Spain, we partitioned the effects of forest amount versus fragmentation and applied logistic regression to model occurrences of 16 species. For nine models showing robustness according to a set of quality criteria we subsequently defined two empirical fragmentation scenarios, minimum and maximum, and quantified species' sensitivity to forest contraction with no fragmentation, and to fragmentation under constant forest cover. We finally assessed how the extinction threshold of each species (the habitat amount below which it cannot persist) varies under no and maximum fragmentation. Consistent with their preference for forest habitats probability occurrences of all species decreased as forest cover contracted. On average, herbs did not show significant sensitivity to fragmentation whereas ferns were favored. In line with theory, fragmentation yielded higher extinction thresholds for two species. For the remaining species, fragmentation had either positive or non-significant effects. We interpret these differences as reflecting species-specific traits and conclude that although forest amount is of

  12. Effects of microhabitat on palm seed predation in two forest fragments in southeast Brazil

    NASA Astrophysics Data System (ADS)

    Fleury, Marina; Galetti, Mauro

    2004-12-01

    The establishment of plants depends crucially on where seeds are deposited in the environment. Some authors suggest that in forest understory seed predation is lower than in gaps, and higher than at the forest edge. However, most studies have been carried out in large forest patches and very little is known about the effects of microhabitat conditions on seed predation in forest fragments. We evaluated the effects of three microhabitats (gaps, forest edge, and understory) on seed predation of two palm species ( Euterpe edulis and Syagrus romanzoffiana) in two semi-deciduous forest fragments (230 and 2100 ha) in southeast Brazil. Our objective was to test two hypotheses: (1) Low rodent abundance in small fragments as a result of meso-predator action levels leads to lower seed predation in small fragments. (2) Most mammal species in small fragments are generalists with respect to diet and habitat, so that seed predation is similar in different microhabitats (gaps, forest edge and understory) in the small fragment, but not in the larger one. The study community of small fragments is usually composed of generalist species (in diet and habitat aspects), so we expected the same rate of seed predation among microhabitats (gaps, forest edge and understory) in the tested smaller fragment. The experiment was carried out in the dry season (for E. edulis) and in the wet season (for S. romanzoffiana) in 1999. We conclude that post-dispersal seed predation in forest fragments can be directly connected with mammal communities, reflecting their historical and ecological aspects.

  13. Measurement and management of human-induced patterns of forest fragmentation: a case study.

    PubMed

    Tole, Lise

    2006-06-01

    In many tropical developing countries, the twin pressures of population and poverty are resulting in substantial fragmentation of forests, increasing the probability of extinction for many species, Forest fragmentation occurs when large contiguous forests are perforated by small holes or broken up into edges and smaller patches to form a nonforested matrix of open spaces. Thus, forest fragmentation refers not only to the area of forest cleared, but also to the pattern of this clearance, the resulting forest's spatial properties. Both characteristics are important for species survivability. Apart from opening up forests to many abiotic and biotic influences, fragmentation can affect species dispersal and migration through its effects on forest connectivity. Landscape ecology conceptualizes connectivity as a gradient of critical thresholds, ranging from the large intact forest to the small unconnected forest patch. This article reports results from a multiple-scale analysis of forest fragmentation in Jamaica's Cockpit Country, an area of once contiguous forest now under threat from human encroachment. Spatial forest data derived from classification of ETM+ satellite imagery are used to measure fragmentation patterns representing various degrees of forest connectivity and density. The results suggest that, overall, 81% of the region is in forest. However, fragmentation patterns also suggest that this forest is riven with extensive perforations indicative of an early stage in the decline of contiguity. The results provided by the spatial fragmentation model are a first step in the design of effective conservation and rehabilitation plans for the area. The article concludes with a discussion of possible multiscale management options for the region.

  14. Limited effect of anthropogenic habitat fragmentation on molecular diversity in a rain forest skink, Gnypetoscincus queenslandiae.

    PubMed

    Sumner, Joanna; Jessop, Tim; Paetkau, David; Moritz, Craig

    2004-02-01

    To examine the effects of recent habitat fragmentation, we assayed genetic diversity in a rain forest endemic lizard, the prickly forest skink (Gnypetoscincus queenslandiae), from seven forest fragments and five sites in continuous forest on the Atherton tableland of northeastern Queensland, Australia. The rain forest in this region was fragmented by logging and clearing for dairy farms in the early 1900s and most forest fragments studied have been isolated for 50-80 years or nine to 12 skink generations. We genotyped 411 individuals at nine microsatellite DNA loci and found fewer alleles per locus in prickly forest skinks from small rain forest fragments and a lower ratio of allele number to allele size range in forest fragments than in continuous forest, indicative of a decrease in effective population size. In contrast, and as expected for populations with small neighbourhood sizes, neither heterozygosity nor variance in allele size differed between fragments and sites in continuous forests. Considering measures of among population differentiation, there was no increase in FST among fragments and a significant isolation by distance pattern was identified across all 12 sites. However, the relationship between genetic (FST) and geographical distance was significantly stronger for continuous forest sites than for fragments, consistent with disruption of gene flow among the latter. The observed changes in genetic diversity within and among populations are small, but in the direction predicted by the theory of genetic erosion in recently fragmented populations. The results also illustrate the inherent difficulty in detecting genetic consequences of recent habitat fragmentation, even in genetically variable species, and especially when effective population size and dispersal rates are low.

  15. Spatial and temporal changes in bird assemblages in forest fragments in an eastern Amazonian savannah

    PubMed Central

    Cintra, Renato; Magnusson, William E; Albernaz, Ana

    2013-01-01

    We investigated the effects of forest fragmentation on bird assemblages in an Amazonian savannah landscape with forest fragments that have been isolated for more than 100 years. The study was conducted in areas surrounding the village of Alter do Chão (2°31'S, 55°00'W), Santarém, Brazil. Bird surveys and measurements of tree density were undertaken in 25 areas, with 19 plots in forest fragments of different sizes and six in an area of continuous forest. Data on forest-fragment size, perimeter, and isolation were obtained from a georeferenced satellite image. Variation in number of bird species recorded per plot was not related to vegetation structure (tree density). The number of bird species recorded per plot increased significantly only with fragment area, but was not influenced by fragment shape or degree of isolation, even when considering species from the savannah matrix in the analysis. Fragments had fewer rare species. Multivariate ordination analyses (multiple dimensional scaling, [MDS]) indicated that bird species composition changed along a gradient from small to large forest fragments and continuous-forest areas. In the Amazonian savannah landscapes of Alter do Chão, the organization and composition of bird assemblages in forest fragments are affected by local long-term forest-fragmentation processes. Differences in the number of bird species recorded per plot and assemblage composition between forest fragments and continuous forest were not influenced by forest structure, suggesting that the observed patterns in species composition result from the effects of fragmentation per se rather than from preexisting differences in vegetation structure between sites. Nevertheless, despite their long history of isolation, the forest fragments still preserve a large proportion (on average 80%) of the avifauna found in continuous-forest areas. The fragments at Alter do Chão are surrounded by natural (rather than planted) grassland, with many trees in the

  16. Spatial and temporal changes in bird assemblages in forest fragments in an eastern Amazonian savannah.

    PubMed

    Cintra, Renato; Magnusson, William E; Albernaz, Ana

    2013-09-01

    We investigated the effects of forest fragmentation on bird assemblages in an Amazonian savannah landscape with forest fragments that have been isolated for more than 100 years. The study was conducted in areas surrounding the village of Alter do Chão (2°31'S, 55°00'W), Santarém, Brazil. Bird surveys and measurements of tree density were undertaken in 25 areas, with 19 plots in forest fragments of different sizes and six in an area of continuous forest. Data on forest-fragment size, perimeter, and isolation were obtained from a georeferenced satellite image. Variation in number of bird species recorded per plot was not related to vegetation structure (tree density). The number of bird species recorded per plot increased significantly only with fragment area, but was not influenced by fragment shape or degree of isolation, even when considering species from the savannah matrix in the analysis. Fragments had fewer rare species. Multivariate ordination analyses (multiple dimensional scaling, [MDS]) indicated that bird species composition changed along a gradient from small to large forest fragments and continuous-forest areas. In the Amazonian savannah landscapes of Alter do Chão, the organization and composition of bird assemblages in forest fragments are affected by local long-term forest-fragmentation processes. Differences in the number of bird species recorded per plot and assemblage composition between forest fragments and continuous forest were not influenced by forest structure, suggesting that the observed patterns in species composition result from the effects of fragmentation per se rather than from preexisting differences in vegetation structure between sites. Nevertheless, despite their long history of isolation, the forest fragments still preserve a large proportion (on average 80%) of the avifauna found in continuous-forest areas. The fragments at Alter do Chão are surrounded by natural (rather than planted) grassland, with many trees in the

  17. Discerning Fragmentation Dynamics of Tropical Forest and Wetland during Reforestation, Urban Sprawl, and Policy Shifts

    PubMed Central

    Gao, Qiong; Yu, Mei

    2014-01-01

    Despite the overall trend of worldwide deforestation over recent decades, reforestation has also been found and is expected in developing countries undergoing fast urbanization and agriculture abandonment. The consequences of reforestation on landscape patterns are seldom addressed in the literature, despite their importance in evaluating biodiversity and ecosystem functions. By analyzing long-term land cover changes in Puerto Rico, a rapidly reforested (6 to 42% during 1940–2000) and urbanized tropical island, we detected significantly different patterns of fragmentation and underlying mechanisms among forests, urban areas, and wetlands. Forest fragmentation is often associated with deforestation. However, we also found significant fragmentation during reforestation. Urban sprawl and suburb development have a dominant impact on forest fragmentation. Reforestation mostly occurs along forest edges, while significant deforestation occurs in forest interiors. The deforestation process has a much stronger impact on forest fragmentation than the reforestation process due to their different spatial configurations. In contrast, despite the strong interference of coastal urbanization, wetland aggregation has occurred due to the effective implementation of laws/regulations for wetland protection. The peak forest fragmentation shifted toward rural areas, indicating progressively more fragmentation in forest interiors. This shift is synchronous with the accelerated urban sprawl as indicated by the accelerated shift of the peak fragmentation index of urban cover toward rural areas, i.e., 1.37% yr−1 in 1977–1991 versus 2.17% yr−1 in 1991–2000. Based on the expected global urbanization and the regional forest transition from deforested to reforested, the fragmented forests and aggregated wetlands in this study highlight possible forest fragmentation processes during reforestation in an assessment of biodiversity and functions and suggest effective laws/regulations in

  18. Discerning fragmentation dynamics of tropical forest and wetland during reforestation, urban sprawl, and policy shifts.

    PubMed

    Gao, Qiong; Yu, Mei

    2014-01-01

    Despite the overall trend of worldwide deforestation over recent decades, reforestation has also been found and is expected in developing countries undergoing fast urbanization and agriculture abandonment. The consequences of reforestation on landscape patterns are seldom addressed in the literature, despite their importance in evaluating biodiversity and ecosystem functions. By analyzing long-term land cover changes in Puerto Rico, a rapidly reforested (6 to 42% during 1940-2000) and urbanized tropical island, we detected significantly different patterns of fragmentation and underlying mechanisms among forests, urban areas, and wetlands. Forest fragmentation is often associated with deforestation. However, we also found significant fragmentation during reforestation. Urban sprawl and suburb development have a dominant impact on forest fragmentation. Reforestation mostly occurs along forest edges, while significant deforestation occurs in forest interiors. The deforestation process has a much stronger impact on forest fragmentation than the reforestation process due to their different spatial configurations. In contrast, despite the strong interference of coastal urbanization, wetland aggregation has occurred due to the effective implementation of laws/regulations for wetland protection. The peak forest fragmentation shifted toward rural areas, indicating progressively more fragmentation in forest interiors. This shift is synchronous with the accelerated urban sprawl as indicated by the accelerated shift of the peak fragmentation index of urban cover toward rural areas, i.e., 1.37% yr-1 in 1977-1991 versus 2.17% yr-1 in 1991-2000. Based on the expected global urbanization and the regional forest transition from deforested to reforested, the fragmented forests and aggregated wetlands in this study highlight possible forest fragmentation processes during reforestation in an assessment of biodiversity and functions and suggest effective laws/regulations in land

  19. Forest fragmentation and selective logging have inconsistent effects on multiple animal-mediated ecosystem processes in a tropical forest.

    PubMed

    Schleuning, Matthias; Farwig, Nina; Peters, Marcell K; Bergsdorf, Thomas; Bleher, Bärbel; Brandl, Roland; Dalitz, Helmut; Fischer, Georg; Freund, Wolfram; Gikungu, Mary W; Hagen, Melanie; Garcia, Francisco Hita; Kagezi, Godfrey H; Kaib, Manfred; Kraemer, Manfred; Lung, Tobias; Naumann, Clas M; Schaab, Gertrud; Templin, Mathias; Uster, Dana; Wägele, J Wolfgang; Böhning-Gaese, Katrin

    2011-01-01

    Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the

  20. Forest Fragmentation and Selective Logging Have Inconsistent Effects on Multiple Animal-Mediated Ecosystem Processes in a Tropical Forest

    PubMed Central

    Schleuning, Matthias; Farwig, Nina; Peters, Marcell K.; Bergsdorf, Thomas; Bleher, Bärbel; Brandl, Roland; Dalitz, Helmut; Fischer, Georg; Freund, Wolfram; Gikungu, Mary W.; Hagen, Melanie; Garcia, Francisco Hita; Kagezi, Godfrey H.; Kaib, Manfred; Kraemer, Manfred; Lung, Tobias; Schaab, Gertrud; Templin, Mathias; Uster, Dana; Wägele, J. Wolfgang; Böhning-Gaese, Katrin

    2011-01-01

    Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the

  1. Genetic signature of population fragmentation varies with mobility in seven bird species of a fragmented Kenyan cloud forest.

    PubMed

    Callens, Tom; Galbusera, Peter; Matthysen, Erik; Durand, Eric Y; Githiru, Mwangi; Huyghe, Jeroen R; Lens, Luc

    2011-05-01

    Habitat fragmentation can restrict geneflow, reduce neighbourhood effective population size, and increase genetic drift and inbreeding in small, isolated habitat remnants. The extent to which habitat fragmentation leads to population fragmentation, however, differs among landscapes and taxa. Commonly, researchers use information on the current status of a species to predict population effects of habitat fragmentation. Such methods, however, do not convey information on species-specific responses to fragmentation. Here, we compare levels of past population differentiation, estimated from microsatellite genotypes, with contemporary dispersal rates, estimated from multi-strata capture-recapture models, to infer changes in mobility over time in seven sympatric, forest-dependent bird species of a Kenyan cloud forest archipelago. Overall, populations of sedentary species were more strongly differentiated and clustered compared to those of vagile ones, while geographical patterning suggested an important role of landscape structure in shaping genetic variation. However, five of seven species with broadly similar levels of genetic differentiation nevertheless differed substantially in their current dispersal rates. We conclude that post-fragmentation levels of vagility, without reference to past population connectivity, may not be the best predictor of how forest fragmentation affects the life history of forest-dependent species. As effective conservation strategies often hinge on accurate prediction of shifts in ecological and genetic relationships among populations, conservation practices based solely upon current population abundances or movements may, in the long term, prove to be inadequate.

  2. USE OF ROAD MAPS IN NATIONAL ASSESSMENTS OF FOREST FRAGMENTATION IN THE UNITED STATES

    EPA Science Inventory

    Including road-mediated forest fragmentation is a contentious issue in United States national assessments. We compared fragmentation as calculated from national land-cover maps alone, and from land-cover maps in combination with road maps. The increment of forest edge from roads ...

  3. Does Tropical Forest Fragmentation Increase Long-Term Variability of Butterfly Communities?

    PubMed Central

    Leidner, Allison K.; Haddad, Nick M.; Lovejoy, Thomas E.

    2010-01-01

    Habitat fragmentation is a major driver of biodiversity loss. Yet, the overall effects of fragmentation on biodiversity may be obscured by differences in responses among species. These opposing responses to fragmentation may be manifest in higher variability in species richness and abundance (termed hyperdynamism), and in predictable changes in community composition. We tested whether forest fragmentation causes long-term hyperdynamism in butterfly communities, a taxon that naturally displays large variations in species richness and community composition. Using a dataset from an experimentally fragmented landscape in the central Amazon that spanned 11 years, we evaluated the effect of fragmentation on changes in species richness and community composition through time. Overall, adjusted species richness (adjusted for survey duration) did not differ between fragmented forest and intact forest. However, spatial and temporal variation of adjusted species richness was significantly higher in fragmented forests relative to intact forest. This variation was associated with changes in butterfly community composition, specifically lower proportions of understory shade species and higher proportions of edge species in fragmented forest. Analysis of rarefied species richness, estimated using indices of butterfly abundance, showed no differences between fragmented and intact forest plots in spatial or temporal variation. These results do not contradict the results from adjusted species richness, but rather suggest that higher variability in butterfly adjusted species richness may be explained by changes in butterfly abundance. Combined, these results indicate that butterfly communities in fragmented tropical forests are more variable than in intact forest, and that the natural variability of butterflies was not a buffer against the effects of fragmentation on community dynamics. PMID:20224772

  4. Does tropical forest fragmentation increase long-term variability of butterfly communities?

    PubMed

    Leidner, Allison K; Haddad, Nick M; Lovejoy, Thomas E

    2010-03-10

    Habitat fragmentation is a major driver of biodiversity loss. Yet, the overall effects of fragmentation on biodiversity may be obscured by differences in responses among species. These opposing responses to fragmentation may be manifest in higher variability in species richness and abundance (termed hyperdynamism), and in predictable changes in community composition. We tested whether forest fragmentation causes long-term hyperdynamism in butterfly communities, a taxon that naturally displays large variations in species richness and community composition. Using a dataset from an experimentally fragmented landscape in the central Amazon that spanned 11 years, we evaluated the effect of fragmentation on changes in species richness and community composition through time. Overall, adjusted species richness (adjusted for survey duration) did not differ between fragmented forest and intact forest. However, spatial and temporal variation of adjusted species richness was significantly higher in fragmented forests relative to intact forest. This variation was associated with changes in butterfly community composition, specifically lower proportions of understory shade species and higher proportions of edge species in fragmented forest. Analysis of rarefied species richness, estimated using indices of butterfly abundance, showed no differences between fragmented and intact forest plots in spatial or temporal variation. These results do not contradict the results from adjusted species richness, but rather suggest that higher variability in butterfly adjusted species richness may be explained by changes in butterfly abundance. Combined, these results indicate that butterfly communities in fragmented tropical forests are more variable than in intact forest, and that the natural variability of butterflies was not a buffer against the effects of fragmentation on community dynamics.

  5. The Importance of Maize Management on Dung Beetle Communities in Atlantic Forest Fragments

    PubMed Central

    Campos, Renata Calixto; Hernández, Malva Isabel Medina

    2015-01-01

    Dung beetle community structures changes due to the effects of destruction, fragmentation, isolation and decrease in tropical forest area, and therefore are considered ecological indicators. In order to assess the influence of type of maize cultivated and associated maize management on dung beetle communities in Atlantic Forest fragments surrounded by conventional and transgenic maize were evaluated 40 Atlantic Forest fragments of different sizes, 20 surrounded by GM maize and 20 surrounded by conventional maize, in February 2013 and 2014 in Southern Brazil. After applying a sampling protocol in each fragment (10 pitfall traps baited with human feces or carrion exposed for 48 h), a total of 3454 individuals from 44 species were captured: 1142 individuals from 38 species in GM maize surrounded fragments, and 2312 from 42 species in conventional maize surrounded fragments. Differences in dung beetle communities were found between GM and conventional maize communities. As expected for fragmented areas, the covariance analysis showed a greater species richness in larger fragments under both conditions; however species richness was greater in fragments surrounded by conventional maize. Dung beetle structure in the forest fragments was explained by environmental variables, fragment area, spatial distance and also type of maize (transgenic or conventional) associated with maize management techniques. In Southern Brazil’s scenario, the use of GM maize combined with associated agricultural management may be accelerating the loss of diversity in Atlantic Forest areas, and consequently, important ecosystem services provided by dung beetles may be lost. PMID:26694874

  6. The Importance of Maize Management on Dung Beetle Communities in Atlantic Forest Fragments.

    PubMed

    Campos, Renata Calixto; Hernández, Malva Isabel Medina

    2015-01-01

    Dung beetle community structures changes due to the effects of destruction, fragmentation, isolation and decrease in tropical forest area, and therefore are considered ecological indicators. In order to assess the influence of type of maize cultivated and associated maize management on dung beetle communities in Atlantic Forest fragments surrounded by conventional and transgenic maize were evaluated 40 Atlantic Forest fragments of different sizes, 20 surrounded by GM maize and 20 surrounded by conventional maize, in February 2013 and 2014 in Southern Brazil. After applying a sampling protocol in each fragment (10 pitfall traps baited with human feces or carrion exposed for 48 h), a total of 3454 individuals from 44 species were captured: 1142 individuals from 38 species in GM maize surrounded fragments, and 2312 from 42 species in conventional maize surrounded fragments. Differences in dung beetle communities were found between GM and conventional maize communities. As expected for fragmented areas, the covariance analysis showed a greater species richness in larger fragments under both conditions; however species richness was greater in fragments surrounded by conventional maize. Dung beetle structure in the forest fragments was explained by environmental variables, fragment area, spatial distance and also type of maize (transgenic or conventional) associated with maize management techniques. In Southern Brazil's scenario, the use of GM maize combined with associated agricultural management may be accelerating the loss of diversity in Atlantic Forest areas, and consequently, important ecosystem services provided by dung beetles may be lost.

  7. Taxonomic and functional divergence of tree assemblages in a fragmented tropical forest.

    PubMed

    Sfair, Julia C; Arroyo-Rodríguez, Víctor; Santos, Bráulio A; Tabarelli, Marcelo

    2016-09-01

    Tropical forests are being exposed to increasing levels of habitat loss and fragmentation, threatening the maintenance of global biodiversity. However, the effect that land-use change may have on the spatial dissimilarities in taxonomic and functional composition of remaining assemblages (i.e., taxonomic/functional β-diversity) remains poorly understood. We examined a large vegetation database from an old and severely fragmented Atlantic forest landscape to test two alternative hypotheses: (1) tree assemblages experience a taxonomic and functional homogenization (reduced β-diversity) between forest fragments and along forest edges, or alternatively, (2) these edge-affected forests show increased taxonomic and functional differentiation (increased β-diversity) when compared to forest interior (reference) stands. Taxonomic and functional β-diversity were examined via novel abundance-based metrics and considering functional traits related to plant dispersion, recruitment, and growth. Overall, taxonomic β-diversity among fragments was significantly higher than among edge and reference plots. Edge plots also showed higher β-diversity than reference plots, but only when considering dominant species. In functional terms, β-diversity among reference plots was also lower than among forest fragments and among edge plots. These patterns support the landscape-divergence hypothesis, which postulates that variable human disturbances among forest fragments and along forest edges can lead to contrasting trajectories of vegetation changes, thus increasing the compositional and functional differentiation of tree communities in these emerging environments. Our results also show that such differentiation can preserve landscape-wide biodiversity, thus overriding negative effects of habitat fragmentation on local (α) diversity. Therefore, our findings demonstrate that forest fragments and forest edges can be more valuable for maintaining species diversity and ecosystem function

  8. Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient.

    PubMed

    Orihuela, Rodrigo L L; Peres, Carlos A; Mendes, Gabriel; Jarenkow, João A; Tabarelli, Marcelo

    2015-01-01

    We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide.

  9. Epiphyte biodiversity in the coffee agricultural matrix: canopy stratification and distance from forest fragments.

    PubMed

    Moorhead, Leigh C; Philpott, Stacy M; Bichier, Peter

    2010-06-01

    Quality of the agricultural matrix profoundly affects biodiversity and dispersal in agricultural areas. Vegetatively complex coffee agroecosystems maintain species richness at larger distances from the forest. Epiphytes colonize canopy trees and provide resources for birds and insects and thus effects of agricultural production on epiphytes may affect other species. We compared diversity, composition, and vertical stratification of epiphytes in a forest fragment and in two coffee farms differing in management intensity in southern Mexico. We also examined spatial distribution of epiphytes with respect to the forest fragment to examine quality of the two agricultural matrix types for epiphyte conservation. We sampled vascular epiphytes in a forest fragment, a shade polyculture farm, and a shade monoculture farm at 100 m, 200 m, and 400 m from the forest. Epiphyte and orchid richness was greater in the forest than in the monoculture but richness was similar in the forest and polyculture farm. Epiphyte species composition differed with habitat type, but not with distance from the forest. In the forest, epiphytes were distributed throughout tree canopies, but in the farms, epiphytes were primarily found on trunks and larger branches. Epiphyte richness and species similarity to forest species declined with distance from the forest fragment in the monoculture, but richness and similarity to forest species did not decline with distance from forest in the polyculture. This suggests polyculture coffee has greater conservation value. In contrast, monoculture coffee is likely a sink habitat for epiphytes dispersing from forests into coffee. Coffee farms differ from forests in terms of the habitat they provide and species composition, thus protecting forest fragments is essential for epiphyte conservation. Nonetheless, in agricultural landscapes, vegetatively complex coffee farms may contribute to conservation of epiphytes more than other agricultural land uses.

  10. Alternative Modelling Approach to Spatial Harvest Scheduling with Respect to Fragmentation of Forest Ecosystem

    NASA Astrophysics Data System (ADS)

    Marušák, Róbert; Kašpar, Jan; Hlavatý, Robert; Kotek, Václav; Kuželka, Karel; Vopěnka, Petr

    2015-11-01

    Fragmentation of the forests affects forest ecosystems by changing the composition, shape, and configuration of the resulting patches. Subsequently, the prevailing conditions vary between patches. The exposure to the sun decreases from the patch boundary to the patch interior and this forms core and edge areas within each patch. Forest harvesting and, in particular, the clear-cut management system which is still preferred in many European countries has a significant impact on forest fragmentation. There are many indices of measuring fragmentation: non-spatial and spatial. The non-spatial indices measure the composition of patches, while the spatial indices measure both the shape and configuration of the resulting patches. The effect of forest harvesting on fragmentation, biodiversity, and the environment is extensively studied; however, the integration of fragmentation indices in the harvest scheduling model is a new, novel approach. This paper presents a multi-objective integer model of harvest scheduling for clear-cut management system and presents a case study demonstrating its use. Harvest balance and sustainability are ensured by the addition of constraints from the basic principle of the regulated forest model. The results indicate that harvest balance and sustainability can be also achieved in minimizing fragmentation of forest ecosystems. From the analyses presented in this study, it can be concluded that integration of fragmentation into harvest scheduling can provide better spatial structure. It depends on the initial spatial and age structure. It was confirmed that it is possible to find compromise solution while minimizing fragmentation and maximizing harvested area.

  11. Alternative Modelling Approach to Spatial Harvest Scheduling with Respect to Fragmentation of Forest Ecosystem.

    PubMed

    Marušák, Róbert; Kašpar, Jan; Hlavatý, Robert; Kotek, Václav; Kuželka, Karel; Vopěnka, Petr

    2015-11-01

    Fragmentation of the forests affects forest ecosystems by changing the composition, shape, and configuration of the resulting patches. Subsequently, the prevailing conditions vary between patches. The exposure to the sun decreases from the patch boundary to the patch interior and this forms core and edge areas within each patch. Forest harvesting and, in particular, the clear-cut management system which is still preferred in many European countries has a significant impact on forest fragmentation. There are many indices of measuring fragmentation: non-spatial and spatial. The non-spatial indices measure the composition of patches, while the spatial indices measure both the shape and configuration of the resulting patches. The effect of forest harvesting on fragmentation, biodiversity, and the environment is extensively studied; however, the integration of fragmentation indices in the harvest scheduling model is a new, novel approach. This paper presents a multi-objective integer model of harvest scheduling for clear-cut management system and presents a case study demonstrating its use. Harvest balance and sustainability are ensured by the addition of constraints from the basic principle of the regulated forest model. The results indicate that harvest balance and sustainability can be also achieved in minimizing fragmentation of forest ecosystems. From the analyses presented in this study, it can be concluded that integration of fragmentation into harvest scheduling can provide better spatial structure. It depends on the initial spatial and age structure. It was confirmed that it is possible to find compromise solution while minimizing fragmentation and maximizing harvested area.

  12. Birds communities of fragmented forest within highly urbanized landscape in Kuala Lumpur, Malaysia

    NASA Astrophysics Data System (ADS)

    Mohd-Taib, F. S.; Rabiatul-Adawiyah, S.; Md-Nor, S.

    2014-09-01

    Urbanization is one form of forest modification for development purposes. It produces forest fragments scattered in the landscape with different intensity of disturbance. We want to determine the effect of forest fragmentation towards bird community in urbanized landscapes in Kuala Lumpur, namely Sungai Besi Forest Reserve (FR), Bukit Nenas FR and Bukit Sungei Puteh FR. We used mist-netting and direct observation method along established trails. These forests differ in size, vegetation composition and land use history. Results show that these forests show relatively low number of species compared to other secondary forest with only 39 bird species recorded. The largest fragment, Sg. Besi encompassed the highest species richness and abundance with 69% species but lower in diversity. Bukit Nenas, the next smallest fragment besides being the only remaining primary forest has the highest diversity index with 1.866. Bkt. Sg. Puteh the smallest fragment has the lowest species richness and diversity with Shanon diversity index of 1.332. The presence of introduced species such as Corvus splendens (House crow) in all study areas suggest high disturbance encountered by these forests. Nonetheless, these patches comprised of considerably high proportion of native species. In conclusion, different intensity of disturbance due to logging activities and urbanization surrounding the forest directly influenced bird species richness and diversity. These effects however can be compensated by maintaining habitat complexity including high vegetation composition and habitat structure at the landscape level.

  13. A Small Mammal Community in a Forest Fragment, Vegetation Corridor and Coffee Matrix System in the Brazilian Atlantic Forest

    PubMed Central

    Rocha, Mariana Ferreira; Passamani, Marcelo; Louzada, Júlio

    2011-01-01

    The objective of our work was to verify the value of the vegetation corridor in the conservation of small mammals in fragmented tropical landscapes, using a model system in the southeastern Minas Gerais. We evaluated and compared the composition and structure of small mammals in a vegetation corridor, forest fragments and a coffee matrix. A total of 15 species were recorded, and the highest species richness was observed in the vegetation corridor (13 species), followed by the forest fragments (10) and the coffee matrix (6). The absolute abundance was similar between the vegetation corridor and fragments (F = 22.94; p = 0.064), and the greatest differences occurred between the vegetation corridor and the matrix (F = 22.94; p = 0.001) and the forest fragments and the matrix (F = 22.94; p = 0.007). Six species showed significant habitat preference possibly related to the sensitivity of the species to the forest disturbance. Marmosops incanus was the species most sensitive to disturbance; Akodon montensis, Cerradomys subflavus, Gracilinanus microtarsus and Rhipidomys sp. displayed little sensitivity to disturbance, with a high relative abundance in the vegetation corridor. Calomys sp. was the species least affected by habitat disturbance, displaying a high relative abundance in the coffee matrix. Although the vegetation corridors are narrow (4 m width), our results support the hypothesis in which they work as a forest extension, share most species with the forest fragment and support species richness and abundance closer to forest fragments than to the coffee matrix. Our work highlights the importance and cost-effectiveness of these corridors to biodiversity management in the fragmented Atlantic Forest landscapes and at the regional level. PMID:21912591

  14. A small mammal community in a forest fragment, vegetation corridor and coffee matrix system in the Brazilian Atlantic forest.

    PubMed

    Rocha, Mariana Ferreira; Passamani, Marcelo; Louzada, Júlio

    2011-01-01

    The objective of our work was to verify the value of the vegetation corridor in the conservation of small mammals in fragmented tropical landscapes, using a model system in the southeastern Minas Gerais. We evaluated and compared the composition and structure of small mammals in a vegetation corridor, forest fragments and a coffee matrix. A total of 15 species were recorded, and the highest species richness was observed in the vegetation corridor (13 species), followed by the forest fragments (10) and the coffee matrix (6). The absolute abundance was similar between the vegetation corridor and fragments (F = 22.94; p = 0.064), and the greatest differences occurred between the vegetation corridor and the matrix (F = 22.94; p = 0.001) and the forest fragments and the matrix (F = 22.94; p = 0.007). Six species showed significant habitat preference possibly related to the sensitivity of the species to the forest disturbance. Marmosops incanus was the species most sensitive to disturbance; Akodon montensis, Cerradomys subflavus, Gracilinanus microtarsus and Rhipidomys sp. displayed little sensitivity to disturbance, with a high relative abundance in the vegetation corridor. Calomys sp. was the species least affected by habitat disturbance, displaying a high relative abundance in the coffee matrix. Although the vegetation corridors are narrow (4 m width), our results support the hypothesis in which they work as a forest extension, share most species with the forest fragment and support species richness and abundance closer to forest fragments than to the coffee matrix. Our work highlights the importance and cost-effectiveness of these corridors to biodiversity management in the fragmented Atlantic Forest landscapes and at the regional level.

  15. A 50-m Forest Cover Map in Southeast Asia from ALOS/PALSAR and Its Application on Forest Fragmentation Assessment

    PubMed Central

    Dong, Jinwei; Xiao, Xiangming; Sheldon, Sage; Biradar, Chandrashekhar; Zhang, Geli; Dinh Duong, Nguyen; Hazarika, Manzul; Wikantika, Ketut; Takeuhci, Wataru; Moore, Berrien

    2014-01-01

    Southeast Asia experienced higher rates of deforestation than other continents in the 1990s and still was a hotspot of forest change in the 2000s. Biodiversity conservation planning and accurate estimation of forest carbon fluxes and pools need more accurate information about forest area, spatial distribution and fragmentation. However, the recent forest maps of Southeast Asia were generated from optical images at spatial resolutions of several hundreds of meters, and they do not capture well the exceptionally complex and dynamic environments in Southeast Asia. The forest area estimates from those maps vary substantially, ranging from 1.73×106 km2 (GlobCover) to 2.69×106 km2 (MCD12Q1) in 2009; and their uncertainty is constrained by frequent cloud cover and coarse spatial resolution. Recently, cloud-free imagery from the Phased Array Type L-band Synthetic Aperture Radar (PALSAR) onboard the Advanced Land Observing Satellite (ALOS) became available. We used the PALSAR 50-m orthorectified mosaic imagery in 2009 to generate a forest cover map of Southeast Asia at 50-m spatial resolution. The validation, using ground-reference data collected from the Geo-Referenced Field Photo Library and high-resolution images in Google Earth, showed that our forest map has a reasonably high accuracy (producer's accuracy 86% and user's accuracy 93%). The PALSAR-based forest area estimates in 2009 are significantly correlated with those from GlobCover and MCD12Q1 at national and subnational scales but differ in some regions at the pixel scale due to different spatial resolutions, forest definitions, and algorithms. The resultant 50-m forest map was used to quantify forest fragmentation and it revealed substantial details of forest fragmentation. This new 50-m map of tropical forests could serve as a baseline map for forest resource inventory, deforestation monitoring, reducing emissions from deforestation and forest degradation (REDD+) implementation, and biodiversity. PMID:24465714

  16. A 50-m forest cover map in Southeast Asia from ALOS/PALSAR and its application on forest fragmentation assessment.

    PubMed

    Dong, Jinwei; Xiao, Xiangming; Sheldon, Sage; Biradar, Chandrashekhar; Zhang, Geli; Duong, Nguyen Dinh; Hazarika, Manzul; Wikantika, Ketut; Takeuhci, Wataru; Moore, Berrien

    2014-01-01

    Southeast Asia experienced higher rates of deforestation than other continents in the 1990s and still was a hotspot of forest change in the 2000s. Biodiversity conservation planning and accurate estimation of forest carbon fluxes and pools need more accurate information about forest area, spatial distribution and fragmentation. However, the recent forest maps of Southeast Asia were generated from optical images at spatial resolutions of several hundreds of meters, and they do not capture well the exceptionally complex and dynamic environments in Southeast Asia. The forest area estimates from those maps vary substantially, ranging from 1.73×10(6) km(2) (GlobCover) to 2.69×10(6) km(2) (MCD12Q1) in 2009; and their uncertainty is constrained by frequent cloud cover and coarse spatial resolution. Recently, cloud-free imagery from the Phased Array Type L-band Synthetic Aperture Radar (PALSAR) onboard the Advanced Land Observing Satellite (ALOS) became available. We used the PALSAR 50-m orthorectified mosaic imagery in 2009 to generate a forest cover map of Southeast Asia at 50-m spatial resolution. The validation, using ground-reference data collected from the Geo-Referenced Field Photo Library and high-resolution images in Google Earth, showed that our forest map has a reasonably high accuracy (producer's accuracy 86% and user's accuracy 93%). The PALSAR-based forest area estimates in 2009 are significantly correlated with those from GlobCover and MCD12Q1 at national and subnational scales but differ in some regions at the pixel scale due to different spatial resolutions, forest definitions, and algorithms. The resultant 50-m forest map was used to quantify forest fragmentation and it revealed substantial details of forest fragmentation. This new 50-m map of tropical forests could serve as a baseline map for forest resource inventory, deforestation monitoring, reducing emissions from deforestation and forest degradation (REDD+) implementation, and biodiversity.

  17. Temperate forest fragments maintain aboveground carbon stocks out to the forest edge despite changes in community composition.

    PubMed

    Ziter, Carly; Bennett, Elena M; Gonzalez, Andrew

    2014-11-01

    Edge effects are among the primary mechanisms by which forest fragmentation can influence the link between biodiversity and ecosystem processes, but relatively few studies have quantified these mechanisms in temperate regions. Carbon storage is an important ecosystem function altered by edge effects, with implications for climate change mitigation. Two opposing hypotheses suggest that aboveground carbon (AGC) stocks at the forest edge will (a) decrease due to increased tree mortality and compositional shifts towards smaller, lower wood density species (e.g., as seen in tropical systems) or, less often, (b) increase due to light/temperature-induced increases in diversity and productivity. We used field-based measurements, allometry, and mixed models to investigate the effects of proximity to the forest edge on AGC stocks, species richness, and community composition in 24 forest fragments in southern Quebec. We also asked whether fragment size or connectivity with surrounding forests altered these edge effects. AGC stocks remained constant across a 100 m edge-to-interior gradient in all fragment types, despite changes in tree community composition and stem density consistent with expectations of forest edge effects. We attribute this constancy primarily to compensatory effects of small trees at the forest edge; however, it is due in some cases to the retention of large trees at forest edges, likely a result of forest management. Our results suggest important differences between temperate and tropical fragments with respect to mechanisms linking biodiversity and AGC dynamics. Small temperate forest fragments may be valuable in conservation efforts based on maintaining biodiversity and multiple ecosystem services.

  18. High resolution analysis of tropical forest fragmentation and its impact on the global carbon cycle

    NASA Astrophysics Data System (ADS)

    Brinck, Katharina; Fischer, Rico; Groeneveld, Jürgen; Lehmann, Sebastian; Dantas de Paula, Mateus; Pütz, Sandro; Sexton, Joseph O.; Song, Danxia; Huth, Andreas

    2017-03-01

    Deforestation in the tropics is not only responsible for direct carbon emissions but also extends the forest edge wherein trees suffer increased mortality. Here we combine high-resolution (30 m) satellite maps of forest cover with estimates of the edge effect and show that 19% of the remaining area of tropical forests lies within 100 m of a forest edge. The tropics house around 50 million forest fragments and the length of the world's tropical forest edges sums to nearly 50 million km. Edge effects in tropical forests have caused an additional 10.3 Gt (2.1-14.4 Gt) of carbon emissions, which translates into 0.34 Gt per year and represents 31% of the currently estimated annual carbon releases due to tropical deforestation. Fragmentation substantially augments carbon emissions from tropical forests and must be taken into account when analysing the role of vegetation in the global carbon cycle.

  19. Effects of forest fragmentation on male and female reproductive success in Cestrum parqui (Solanaceae).

    PubMed

    Aguilar, Ramiro; Galetto, Leonardo

    2004-03-01

    In this paper we evaluate the effects of forest fragmentation on male (pollen removal, pollen load, and pollen tubes) and female reproductive success (fruit- and seed-set) of Cestrum parqui, a self-incompatible, pollination-specialist plant species. We also measure focal individual conspecific density to account for possible density-related effects that could influence the response variables. We calculate an index which incorporates male and female fitness and gives an integrated assessment of overall reproductive success. Forest fragmentation strongly affected the amount of pollen grains on stigmas and number of pollen tubes as well as seed-set, decreasing from continuous forest to small forest fragments, whereas focal individual conspecific density failed to explain any of the variability for the studied variables. Declines in overall reproductive success (i.e. male and female) in small forest fragments are ascribed to decreases in both the quality and quantity of pollination. Self-incompatibility coupled with a specialist pollination system may be particularly important traits determining the negative fragmentation effects observed in C. parqui. Logarithmic regression models described the behaviour of the variables along the fragmentation size gradient, allowing us to detect a threshold below which the effects of fragmentation begin to negatively affect reproductive success in C. parqui. Our results emphasize the importance of evaluating both components of the total plant fitness, as well as including simultaneously several aspects of pollination and reproduction processes when assessing the effects of forest fragmentation on plant reproductive success.

  20. Assessing rates of forest change and fragmentation in Alabama, USA, using the vegetation change tracker model

    USGS Publications Warehouse

    Li, M.; Huang, C.; Zhu, Z.; Shi, H.; Lu, H.; Peng, S.

    2009-01-01

    Forest change is of great concern for land use decision makers and conservation communities. Quantitative and spatial forest change information is critical for addressing many pressing issues, including global climate change, carbon budgets, and sustainability. In this study, our analysis focuses on the differences in geospatial patterns and their changes between federal forests and nonfederal forests in Alabama over the time period 1987–2005, by interpreting 163 Landsat Thematic Mapper (TM) scenes using a vegetation change tracker (VCT) model. Our analysis revealed that for the most part of 1990 s and between 2000 and 2005, Alabama lost about 2% of its forest on an annual basis due to disturbances, but much of the losses were balanced by forest regeneration from previous disturbances. The disturbance maps revealed that federal forests were reasonably well protected, with the fragmentation remaining relatively stable over time. In contrast, nonfederal forests, which are predominant in area share (about 95%), were heavily disturbed, clearly demonstrating decreasing levels of fragmentation during the time period 1987–1993 giving way to a subsequent accelerating fragmentation during the time period 1994–2005. Additionally, the identification of the statistical relationships between forest fragmentation status and forest loss rate and forest net change rate in relation to land ownership implied the distinct differences in forest cutting rate and cutting patterns between federal forests and nonfederal forests. The forest spatial change information derived from the model has provided valuable insights regarding regional forest management practices and disturbance regimes, which are closely associated with regional economics and environmental concerns.

  1. Behavioral modifications in northern bearded saki monkeys (Chiropotes satanas chiropotes) in forest fragments of central Amazonia.

    PubMed

    Boyle, Sarah Ann; Smith, Andrew T

    2010-01-01

    We investigated behavioral differences among seven groups of northern bearded saki monkeys (Chiropotes satanas chiropotes) living in five forest fragments and two areas of continuous forest at the Biological Dynamics of Forest Fragments Project study area, located approximately 80 km north of Manaus, Brazil. We collected data in six research cycles from July-August 2003 to January 2005-April 2006. When bearded saki monkeys were present in a study area, we followed the group from dawn until dusk for three consecutive days. Every 5 min, we conducted behavioral scans of all visible individuals. There was a positive relationship between forest size and group size, but animals in the small forest fragments lived at greater densities. Bearded saki monkeys in the smaller fragments spent more time resting, less time traveling, and less time vocalizing, but there was no relationship between forest size and the amount of time spent feeding. Our results indicate that the main behavioral differences among the groups are related to the amount of forest resources (e.g., fruit trees, space) available to the monkeys in the smaller fragments, as well as the resulting smaller group sizes. We stress the need to preserve large tracts of forest and provide connectivity between forest patches.

  2. Differences in seed rain composition in small and large fragments in the northeast Brazilian Atlantic Forest.

    PubMed

    Knörr, U C; Gottsberger, G

    2012-09-01

    Tropical forests are seriously threatened by fragmentation and habitat loss. The impact of fragment size and forest configuration on the composition of seed rain is insufficiently studied. For the present study, seed rain composition of small and large forest fragments (8-388 ha) was assessed in order to identify variations in seed abundance, species richness, seed size and dispersal mode. Seed rain was documented during a 1-year period in three large and four small Atlantic Forest fragments that are isolated by a sugarcane matrix. Total seed rain included 20,518 seeds of 149 species of trees, shrubs, palms, lianas and herbs. Most species and seeds were animal-dispersed. A significant difference in the proportion of seeds and species within different categories of seed size was found between small and large fragments. Small fragments received significantly more very small-sized seeds (<0.3 cm) and less large-seeded species (>1.5 cm) that were generally very rare, with only one species in small and eight in large fragments. We found a negative correlation between the inflow of small-sized seeds and the percentage of forest cover. Species richness was lower in small than in large fragments, but the difference was not very pronounced. Given our results, we propose changing plant species pools through logging, tree mortality and a high inflow of pioneer species and lianas, especially in small forest fragments and areas with low forest cover. Connecting forest fragments through corridors and reforestation with local large-seeded tree species may facilitate the maintenance of species diversity.

  3. Forest cover change and fragmentation using Landsat data in Maçka State Forest Enterprise in Turkey.

    PubMed

    Cakir, Günay; Sivrikaya, Fatih; Keleş, Sedat

    2008-02-01

    Monitoring forest cover change and understanding the dynamic of forest cover is increasingly important in sustainable development and management of forest ecosystems. This paper uses remote sensing (RS) techniques to monitor forest cover change in Maçka State Forest Enterprise (MSFE) located in NE of Turkey through 1975 to 2000 and then analyses spatial and temporal changes in forest cover by Geographical Information Systems (GIS) and FRAGSTATStrade mark. Forest cover changes were detected from a time series of satellite images of Landsat MSS in 1975, Landsat TM in 1987, and Landsat ETM+ in 2000 using RS and GIS. The results showed that total forest area, productive forest area and degraded forest area increased while broadleaf forest area and non forest area decreased. Mixed forest and degraded forest increased during the first (1975-1987) period, but decreased during the second (1987-2000) period. During the whole study period, the annual forestation rate was 152 ha year(-1), equivalent to 0.27% year(-1) using the compound-interest-rate formula. The total number of patches increased from 36,204 to 48,092 (33%), and mean size of forest patch (MPS) decreased from 2.8 ha to 2.1 ha during a 25 year period. Number of smaller patches (patches in 0-100 ha size class) increased, indicating more fragmented landscape over time that might create a risk for the maintenance of biodiversity of the area. While total population increased from 1975 to 2000 (3.7%), rural population constantly decreased. The increase of forest areas may well be explained by the fact that demographic movement of rural areas concentrated into Maçka City Center. These figures also indicated that decrease in the rural population might likely lead to the release of human pressure to forest areas, probably resulting in a positive development of forest areas.

  4. Carbon emissions from deforestation and forest fragmentation in the Brazilian Amazon

    NASA Astrophysics Data System (ADS)

    Numata, Izaya; Cochrane, Mark A.; Souza, Carlos M., Jr.; Sales, Marcio H.

    2011-10-01

    Forest-fragmentation-related edge effects are one of the major causes of forest degradation in Amazonia and their spatio-temporal dynamics are highly influenced by annual deforestation patterns. Rapid biomass collapse due to edge effects in forest fragments has been reported in the Brazilian Amazon; however the collective impacts of this process on Amazonian carbon fluxes are poorly understood. We estimated biomass loss and carbon emissions from deforestation and forest fragmentation related to edge effects on the basis of the INPE (Brazilian National Space Research Institute) PRODES deforestation data and forest biomass volume data. The areas and ages of edge forests were calculated annually and the corresponding biomass loss and carbon emissions from these forest edges were estimated using published rates of biomass decay and decomposition corresponding to the areas and ages of edge forests. Our analysis estimated carbon fluxes from deforestation (4195 Tg C) and edge forest (126-221 Tg C) for 2001-10 in the Brazilian Amazon. The impacts of varying rates of deforestation on regional forest fragmentation and carbon fluxes were also investigated, with the focus on two periods: 2001-5 (high deforestation rates) and 2006-10 (low deforestation rates). Edge-released carbon accounted for 2.6-4.5% of deforestation-related carbon emissions. However, the relative importance of carbon emissions from forest fragmentation increased from 1.7-3.0% to 3.3-5.6% of the respective deforestation emissions between the two contrasting deforestation rates. Edge-related carbon fluxes are of increasing importance for basin-wide carbon accounting, especially as regards ongoing reducing emissions from deforestation and forest degradation (REDD) efforts in Brazilian Amazonia.

  5. Trophic structure stability and extinction dynamics of beetles (Coleoptera) in tropical forest fragments

    PubMed Central

    Didham, R. K.

    1998-01-01

    A first analysis of the stability of trophic structure following tropical forest fragmentation was performed in an experimentally fragmented tropical forest landscape in Central Amazonia. A taxonomically and trophically diverse assemblage of 993 species of beetles was sampled from 920 m2 of leaf litter at 46 sites varying in distance from forest edge and fragment area. Beetle density increased significantly towards the forest edge and showed non-linear changes with fragment area, due to the influx of numerous disturbed-area species into 10 ha and 1 ha fragments. There was a marked change in species composition with both decreasing distance from forest edge and decreasing fragment area, but surprisingly this change in composition was not accompanied by a change in species richness. Rarefied species richness did not vary significantly across any of the sites, indicating that local extinctions of deep forest species were balanced by equivalent colonization rates of disturbed-area species. The change in species composition with fragmentation was non-random across trophic groups. Proportions of predator species and xylophage species changed significantly with distance from forest edge, but no area-dependent changes in proportions of species in trophic groups were observed. Trophic structure was also analysed with respect to proportions of abundance in six trophic groups. Proportions of abundance of all trophic groups except xylomycetophages changed markedly with respect to both distance from forest edge and fragment area. Local extinction probabilities calculated for individual beetle species supported theoretical predictions of the differential susceptibility of higher trophic levels to extinction, and of changes in trophic structure following forest fragmentation. To reduce random effects due to sampling error, only abundant species (n = 46) were analysed for extinction probabilities, as defined by absence from samples. Of these common species, 27% had significantly

  6. Tropical Forest Fragmentation Limits Movements, but Not Occurrence of a Generalist Pollinator Species

    PubMed Central

    Volpe, Noelia L.; Robinson, W. Douglas; Frey, Sarah J. K.; Hadley, Adam S.; Betts, Matthew G.

    2016-01-01

    Habitat loss and fragmentation influence species distributions and therefore ecological processes that depend upon them. Pollination may be particularly susceptible to fragmentation, as it depends on frequent pollinator movement. Unfortunately, most pollinators are too small to track efficiently which has precluded testing the hypothesis that habitat fragmentation reduces or eliminates pollen flow by disrupting pollinator movement. We used radio-telemetry to examine space use of the green hermit hummingbird (Phaethornis guy), an important ‘hub’ pollinator of understory flowering plants across substantial portions of the neotropics and the primary pollinator of a keystone plant which shows reduced pollination success in fragmented landscapes. We found that green hermits strongly avoided crossing large stretches of non-forested matrix and preferred to move along stream corridors. Forest gaps as small as 50 m diminished the odds of movement by 50%. Green hermits occurred almost exclusively inside the forest, with the odds of occurrence being 8 times higher at points with >95% canopy cover compared with points having <5% canopy cover. Nevertheless, surprisingly. the species occurred in fragmented landscapes with low amounts of forest (~30% within a 2 km radius). Our results indicate that although green hermits are present even in landscapes with low amounts of tropical forest, movement within these landscapes ends up strongly constrained by forest gaps. Restricted movement of pollinators may be an underappreciated mechanism for widespread declines in pollination and plant fitness in fragmented landscapes, even when in the presence of appropriate pollinators. PMID:27941984

  7. Comparing forest fragmentation and its drivers in China and the USA with Globcover v2.2

    USGS Publications Warehouse

    Li, M.; Mao, L.; Zhou, C.; Vogelmann, J.E.; Zhu, Z.

    2010-01-01

    Forest loss and fragmentation are of major concern to the international community, in large part because they impact so many important environmental processes. The main objective of this study was to assess the differences in forest fragmentation patterns and drivers between China and the conterminous United States (USA). Using the latest 300-m resolution global land cover product, Globcover v2.2, a comparative analysis of forest fragmentation patterns and drivers was made. The fragmentation patterns were characterized by using a forest fragmentation model built on the sliding window analysis technique in association with landscape indices. Results showed that China’s forests were substantially more fragmented than those of the USA. This was evidenced by a large difference in the amount of interior forest area share, with China having 48% interior forest versus the 66% for the USA. China’s forest fragmentation was primarily attributed to anthropogenic disturbances, driven particularly by agricultural expansion from an increasing and large population, as well as poor forest management practices. In contrast, USA forests were principally fragmented by natural land cover types. However, USA urban sprawl contributed more to forest fragmentation than in China. This is closely tied to the USA’s economy, lifestyle and institutional processes. Fragmentation maps were generated from this study, which provide valuable insights and implications regarding habitat planning for rare and endangered species. Such maps enable development of strategic plans for sustainable forest management by identifying areas with high amounts of human-induced fragmentation, which improve risk assessments and enable better targeting for protection and remediation efforts. Because forest fragmentation is a long-term, complex process that is highly related to political, institutional, economic and philosophical arenas, both nations need to take effective and comprehensive measures to mitigate

  8. Edge-related loss of tree phylogenetic diversity in the severely fragmented Brazilian Atlantic forest.

    PubMed

    Santos, Bráulio A; Arroyo-Rodríguez, Víctor; Moreno, Claudia E; Tabarelli, Marcelo

    2010-09-08

    Deforestation and forest fragmentation are known major causes of nonrandom extinction, but there is no information about their impact on the phylogenetic diversity of the remaining species assemblages. Using a large vegetation dataset from an old hyper-fragmented landscape in the Brazilian Atlantic rainforest we assess whether the local extirpation of tree species and functional impoverishment of tree assemblages reduce the phylogenetic diversity of the remaining tree assemblages. We detected a significant loss of tree phylogenetic diversity in forest edges, but not in core areas of small (<80 ha) forest fragments. This was attributed to a reduction of 11% in the average phylogenetic distance between any two randomly chosen individuals from forest edges; an increase of 17% in the average phylogenetic distance to closest non-conspecific relative for each individual in forest edges; and to the potential manifestation of late edge effects in the core areas of small forest remnants. We found no evidence supporting fragmentation-induced phylogenetic clustering or evenness. This could be explained by the low phylogenetic conservatism of key life-history traits corresponding to vulnerable species. Edge effects must be reduced to effectively protect tree phylogenetic diversity in the severely fragmented Brazilian Atlantic forest.

  9. Increased pollen flow counteracts fragmentation in a tropical dry forest: An example from Swietenia humilis Zuccarini

    PubMed Central

    White, G. M.; Boshier, D. H.; Powell, W.

    2002-01-01

    Habitat destruction and the resultant fragmentation of the remaining forest are a common phenomenon in the tropics. Most investigations emphasize the potential dangers of fragmentation in isolating patches of forest and exposing populations to loss of species diversity through founder effects, genetic drift, inbreeding, and restricted gene flow. However, a limited number of studies have shown that gene flow may be extensive in tropical trees, suggesting that it may occur between forest fragments and also “isolated” remnant trees. There is an urgent need to quantify pollen flow within and between forest fragments to test the veracity of such views and determine the genetic value of such fragments for in situ conservation. Microsatellite markers are used to genotype individuals of Swietenia humilis from a highly fragmented forest mosaic to directly quantify pollen-mediated gene flow. Distances of pollen flow more than 10 times greater than previously reported were detected. Our results show that some tropical angiosperm tree species may be much more adaptable and resilient to habitat destruction and fragmentation than previously considered. The description of many remnant trees as isolated or “living dead” may be more a conditioning of human perception than a true reflection of their potential conservation value. PMID:11842203

  10. Assemblages of terrestrial isopods (Isopoda, Oniscidea) in a fragmented forest landscape in Central Europe.

    PubMed

    Tajovský, Karel; Hošek, Jan; Hofmeister, Jeňýk; Wytwer, Jolanta

    2012-01-01

    Terrestrial isopods were collected in 13 forest fragments differing in area (within the range of 0.1 and 254.5 ha), shape and composition of forest vegetation (thermophilous oak, mesophilous oak-hornbeam, thermophilous oak-hornbeam, acidophilous oak, basiphilous oak, beech oak-hornbeam, moist mixed deciduous forest, plantations of deciduous and coniferous trees), all situated in the Český kras Protected Landscape Area, Czech Republic, Central Europe. Number of sites sampled in each fragment of forest depended on its size and ranged from 1 to 7. Altogether 30 sites were sampled. Soil samples (5 per site collected twice a year) and pitfall trapping (5 traps per site in continuous operation throughout a year) during 2008-2009 yielded a total of 14 species of terrestrial isopods. The highest densities and highest epigeic activities of terrestrial isopods were recorded in the smallest fragments of woodland. Although a wider range of habitats were sampled in the larger fragments of woodland there was not a greater diversity of species there and the population densities and epigeic activities recorded there were lower. Porcellium collicola was most abundant in small fragments of woodland regardless the vegetation there. Armadillidium vulgare and Protracheoniscus politus were statistically more abundant in the larger fragments of woodland. The results indicate that forest fragmentation does not necessarily result in a decrease in the species richness of the isopod assemblages in such habitats.

  11. Meta-analysis of the effects of forest fragmentation on interspecific interactions.

    PubMed

    Magrach, Ainhoa; Laurance, William F; Larrinaga, Asier R; Santamaria, Luis

    2014-10-01

    Forest fragmentation dramatically alters species persistence and distribution and affects many ecological interactions among species. Recent studies suggest that mutualisms, such as pollination and seed dispersal, are more sensitive to the negative effects of forest fragmentation than antagonisms, such as predation or herbivory. We applied meta-analytical techniques to evaluate this hypothesis and quantified the relative contributions of different components of the fragmentation process (decreases in fragment size, edge effects, increased isolation, and habitat degradation) to the overall effect. The effects of fragmentation on mutualisms were primarily driven by habitat degradation, edge effects, and fragment isolation, and, as predicted, they were consistently more negative on mutualisms than on antagonisms. For the most studied interaction type, seed dispersal, only certain components of fragmentation had significant (edge effects) or marginally significant (fragment size) effects. Seed size modulated the effect of fragmentation: species with large seeds showed stronger negative impacts of fragmentation via reduced dispersal rates. Our results reveal that different components of the habitat fragmentation process have varying impacts on key mutualisms. We also conclude that antagonistic interactions have been understudied in fragmented landscapes, most of the research has concentrated on particular types of mutualistic interactions such as seed dispersal, and that available studies of interspecific interactions have a strong geographical bias (arising mostly from studies carried out in Brazil, Chile, and the United States).

  12. Predicting primate local extinctions within "real-world" forest fragments: a pan-neotropical analysis.

    PubMed

    Benchimol, Maíra; Peres, Carlos A

    2014-03-01

    Understanding the main drivers of species extinction in human-modified landscapes has gained paramount importance in proposing sound conservation strategies. Primates play a crucial role in maintaining the integrity of forest ecosystem functions and represent the best studied order of tropical terrestrial vertebrates, yet primate species diverge widely in their responses to forest habitat disturbance and fragmentation. Here, we present a robust quantitative review on the synergistic effects of habitat fragmentation on Neotropical forest primates to pinpoint the drivers of species extinction across a wide range of forest patches from Mexico to Argentina. Presence-absence data on 19 primate functional groups were compiled from 705 forest patches and 55 adjacent continuous forest sites, which were nested within 61 landscapes investigated by 96 studies. Forest patches were defined in terms of their size, surrounding matrix and level of hunting pressure on primates, and each functional group was classified according to seven life-history traits. Generalized linear mixed models showed that patch size, forest cover, level of hunting pressure, home range size and trophic status were the main predictors of species persistence within forest isolates for all functional groups pooled together. However, patterns of local extinction varied greatly across taxa, with Alouatta and Callicebus moloch showing the highest occupancy rates even within tiny forest patches, whereas Brachyteles and Leontopithecus occupied fewer than 50% of sites, even in relatively large forest tracts. Our results uncover the main predictors of platyrrhine primate species extinction, highlighting the importance of considering the history of anthropogenic disturbances, the structure of landscapes, and species life-history attributes in predicting primate persistence in Neotropical forest patches. We suggest that large-scale conservation planning of fragmented forest landscapes should prioritize and set

  13. Forest fragments as barriers to fruit fly dispersal: Anastrepha (Diptera: Tephritidae) populations in orchards and adjacent forest fragments in Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    McPhail-type traps baited with ammonium acetate and putrescine were used to monitor populations of Anastrepha obliqua and A. suspensa at four sites in Guánica, Puerto Rico; one forest fragment in Ponce, Puerto Rico; in a commercial mango orchard in Guayanilla, PR; and an experimental carambola orcha...

  14. A multi-scale metrics approach to forest fragmentation for Strategic Environmental Impact Assessment

    SciTech Connect

    Kim, Eunyoung; Song, Wonkyong; Lee, Dongkun

    2013-09-15

    Forests are becoming severely fragmented as a result of land development. South Korea has responded to changing community concerns about environmental issues. The nation has developed and is extending a broad range of tools for use in environmental management. Although legally mandated environmental compliance requirements in South Korea have been implemented to predict and evaluate the impacts of land-development projects, these legal instruments are often insufficient to assess the subsequent impact of development on the surrounding forests. It is especially difficult to examine impacts on multiple (e.g., regional and local) scales in detail. Forest configuration and size, including forest fragmentation by land development, are considered on a regional scale. Moreover, forest structure and composition, including biodiversity, are considered on a local scale in the Environmental Impact Assessment process. Recently, the government amended the Environmental Impact Assessment Act, including the SEA, EIA, and small-scale EIA, to require an integrated approach. Therefore, the purpose of this study was to establish an impact assessment system that minimizes the impacts of land development using an approach that is integrated across multiple scales. This study focused on forest fragmentation due to residential development and road construction sites in selected Congestion Restraint Zones (CRZs) in the Greater Seoul Area of South Korea. Based on a review of multiple-scale impacts, this paper integrates models that assess the impacts of land development on forest ecosystems. The applicability of the integrated model for assessing impacts on forest ecosystems through the SEIA process is considered. On a regional scale, it is possible to evaluate the location and size of a land-development project by considering aspects of forest fragmentation, such as the stability of the forest structure and the degree of fragmentation. On a local scale, land-development projects should

  15. Would protecting tropical forest fragments provide carbon and biodiversity cobenefits under REDD+?

    PubMed

    Magnago, Luiz Fernando S; Magrach, Ainhoa; Laurance, William F; Martins, Sebastião V; Meira-Neto, João Augusto A; Simonelli, Marcelo; Edwards, David P

    2015-09-01

    Tropical forests store vast amounts of carbon and are the most biodiverse terrestrial habitats, yet they are being converted and degraded at alarming rates. Given global shortfalls in the budgets required to prevent carbon and biodiversity loss, we need to seek solutions that simultaneously address both issues. Of particular interest are carbon-based payments under the Reducing Emissions from Deforestation and Forest Degradation (REDD+) mechanism to also conserve biodiversity at no additional cost. One potential is for REDD+ to protect forest fragments, especially within biomes where contiguous forest cover has diminished dramatically, but we require empirical tests of the strength of any carbon and biodiversity cobenefits in such fragmented systems. Using the globally threatened Atlantic Forest landscape, we measured above-ground carbon stocks within forest fragments spanning 13 to 23 442 ha in area and with different degrees of isolation. We related these stocks to tree community structure and to the richness and abundance of endemic and IUCN Red-listed species. We found that increasing fragment size has a positive relationship with above-ground carbon stock and with abundance of IUCN Red-listed species and tree community structure. We also found negative relationships between distance from large forest block and tree community structure, endemic species richness and abundance, and IUCN Red-listed species abundance. These resulted in positive congruence between carbon stocks and Red-listed species, and the abundance and richness of endemic species, demonstrating vital cobenefits. As such, protecting forest fragments in hotspots of biodiversity, particularly larger fragments and those closest to sources, offers important carbon and biodiversity cobenefits. More generally, our results suggest that macroscale models of cobenefits under REDD+ have likely overlooked key benefits at small scales, indicating the necessity to apply models that include finer

  16. Comparison of neotropical migrant landbird populations wintering in tropical forest, isolated forest fragments, and agricultural habitats

    USGS Publications Warehouse

    Robbins, C.S.; Dowell, B.A.; Dawson, D.K.; Colon, J.A.; Estrada, R.; Sutton, A.; Sutton, R.; Weyer, D.; Hagan, John M.; Johnston, David W.

    1992-01-01

    Neotropical migrant bird populations were sampled at 76 sites in seven countries by using mist nets and point counts during a six-winter study. Populations in major agricultural habitats were compared with those in extensive forest and isolated forest fragments. Certain Neotropical migrants, such as the Northern Parula, American Redstart, and the Black-throated Blue, Magnolia, Black-and-white, and Hooded warblers, were present in arboreal agricultural habitats such as pine, cacao, citrus, and shade coffee plantations in relatively large numbers. Many north temperate zone shrub-nesting species, such as the Gray Catbird, White-eyed Vireo, Tennessee Warbler, Common Yellowthroat, and Indigo Bunting, also used agricultural habitats in winter, as did resident hummingbirds and migrant orioles. Ground-foraging migrants, such as thrushes and Kentucky Warblers, were rarely found in the agricultural habitats sampled. Although many Neotropical migrants use some croplands, this use might be severely limited by overgrazing by cattle, by intensive management (such as removal of ground cover in an orchard), or by heavy use of insecticides, herbicides, or fungicides.

  17. Quantitative Analysis of Forest Fragmentation in the Atlantic Forest Reveals More Threatened Bird Species than the Current Red List

    PubMed Central

    Schnell, Jessica K.; Harris, Grant M.; Pimm, Stuart L.; Russell, Gareth J.

    2013-01-01

    Habitat loss and attendant fragmentation threaten the existence of many species. Conserving these species requires a straightforward and objective method that quantifies how these factors affect their survival. Therefore, we compared a variety of metrics that assess habitat fragmentation in bird ranges, using the geographical ranges of 127 forest endemic passerine birds inhabiting the Atlantic Forest of Brazil. A common, non-biological metric — cumulative area of size-ranked fragments within a species range — was misleading, as the least threatened species had the most habitat fragmentation. Instead, we recommend a modified version of metapopulation capacity. The metric links detailed spatial information on fragment sizes and spatial configuration to the birds’ abilities to occupy and disperse across large areas (100,000+ km2). In the Atlantic Forest, metapopulation capacities were largely bimodal, in that most species’ ranges had either low capacity (high risk of extinction) or high capacity (very small risk of extinction). This pattern persisted within taxonomically and ecologically homogenous groups, indicating that it is driven by fragmentation patterns and not differences in species ecology. Worryingly, we found IUCN considers some 28 of 58 species in the low metapopulation capacity cluster to not be threatened. We propose that assessing the effect of fragmentation will separate species more clearly into distinct risk categories than does a simple assessment of remaining habitat. PMID:23734248

  18. Quantitative analysis of forest fragmentation in the atlantic forest reveals more threatened bird species than the current red list.

    PubMed

    Schnell, Jessica K; Harris, Grant M; Pimm, Stuart L; Russell, Gareth J

    2013-01-01

    Habitat loss and attendant fragmentation threaten the existence of many species. Conserving these species requires a straightforward and objective method that quantifies how these factors affect their survival. Therefore, we compared a variety of metrics that assess habitat fragmentation in bird ranges, using the geographical ranges of 127 forest endemic passerine birds inhabiting the Atlantic Forest of Brazil. A common, non-biological metric - cumulative area of size-ranked fragments within a species range - was misleading, as the least threatened species had the most habitat fragmentation. Instead, we recommend a modified version of metapopulation capacity. The metric links detailed spatial information on fragment sizes and spatial configuration to the birds' abilities to occupy and disperse across large areas (100,000+ km(2)). In the Atlantic Forest, metapopulation capacities were largely bimodal, in that most species' ranges had either low capacity (high risk of extinction) or high capacity (very small risk of extinction). This pattern persisted within taxonomically and ecologically homogenous groups, indicating that it is driven by fragmentation patterns and not differences in species ecology. Worryingly, we found IUCN considers some 28 of 58 species in the low metapopulation capacity cluster to not be threatened. We propose that assessing the effect of fragmentation will separate species more clearly into distinct risk categories than does a simple assessment of remaining habitat.

  19. Effects of Forest Fragmentation on Human Risk of Lyme Disease

    EPA Science Inventory

    Percent forest-herbaceous edge repeatedly explained most of the variability in reported Lyme disease rates within a rural-to-urban study gradient across central Maryland and southeastern Pennsylvania. A one-percent increase in forest-herbaceous edge was associated with an increas...

  20. Forest Fragmentation as Cause of Bacterial Transmission among Nonhuman Primates, Humans, and Livestock, Uganda

    PubMed Central

    Gillespie, Thomas R.; Rwego, Innocent B.; Estoff, Elizabeth L.; Chapman, Colin A.

    2008-01-01

    We conducted a prospective study of bacterial transmission among humans, nonhuman primates (primates hereafter), and livestock in western Uganda. Humans living near forest fragments harbored Escherichia coli bacteria that were ≈75% more similar to bacteria from primates in those fragments than to bacteria from primates in nearby undisturbed forests. Genetic similarity between human/livestock and primate bacteria increased ≈3-fold as anthropogenic disturbance within forest fragments increased from moderate to high. Bacteria harbored by humans and livestock were approximately twice as similar to those of red-tailed guenons, which habitually enter human settlements to raid crops, than to bacteria of other primate species. Tending livestock, experiencing gastrointestinal symptoms, and residing near a disturbed forest fragment increased genetic similarity between a participant’s bacteria and those of nearby primates. Forest fragmentation, anthropogenic disturbance within fragments, primate ecology, and human behavior all influence bidirectional, interspecific bacterial transmission. Targeted interventions on any of these levels should reduce disease transmission and emergence. PMID:18760003

  1. Near-complete extinction of native small mammal fauna 25 years after forest fragmentation.

    PubMed

    Gibson, Luke; Lynam, Antony J; Bradshaw, Corey J A; He, Fangliang; Bickford, David P; Woodruff, David S; Bumrungsri, Sara; Laurance, William F

    2013-09-27

    Tropical forests continue to be felled and fragmented around the world. A key question is how rapidly species disappear from forest fragments and how quickly humans must restore forest connectivity to minimize extinctions. We surveyed small mammals on forest islands in Chiew Larn Reservoir in Thailand 5 to 7 and 25 to 26 years after isolation and observed the near-total loss of native small mammals within 5 years from <10-hectare (ha) fragments and within 25 years from 10- to 56-ha fragments. Based on our results, we developed an island biogeographic model and estimated mean extinction half-life (50% of resident species disappearing) to be 13.9 years. These catastrophic extinctions were probably partly driven by an invasive rat species; such biotic invasions are becoming increasingly common in human-modified landscapes. Our results are thus particularly relevant to other fragmented forest landscapes and suggest that small fragments are potentially even more vulnerable to biodiversity loss than previously thought.

  2. Effects of climate and forest structure on palms, bromeliads and bamboos in Atlantic Forest fragments of Northeastern Brazil.

    PubMed

    Hilário, R R; Toledo, J J

    2016-01-01

    Palms, bromeliads and bamboos are key elements of tropical forests and understanding the effects of climate, anthropogenic pressure and forest structure on these groups is crucial to forecast structural changes in tropical forests. Therefore, we investigated the effects of these factors on the abundance of these groups in 22 Atlantic forest fragments of Northeastern Brazil. Abundance of bromeliads and bamboos were assessed through indexes. Palms were counted within a radius of 20 m. We also obtained measures of vegetation structure, fragment size, annual precipitation, precipitation seasonality and human population density. We tested the effects of these predictors on plant groups using path analysis. Palm abundance was higher in taller forests with larger trees, closed canopy and sparse understory, which may be a result of the presence of seed dispersers and specific attributes of local palm species. Bromeliads were negatively affected by both annual precipitation and precipitation seasonality, what may reflect adaptations of these plants to use water efficiently, but also the need to capture water in a regular basis. Bamboos were not related to any predictor variable. As climate and forest structure affected the abundance of bromeliads and palms, human-induced climatic changes and disturbances in forest structure may modify the abundance of these groups. In addition, soil properties and direct measurements of human disturbance should be used in future studies in order to improve the predictability of models about plant groups in Northeastern Atlantic Forest.

  3. The Effect of the Landscape Matrix on the Distribution of Dung and Carrion Beetles in a Fragmented Tropical Rain Forest

    PubMed Central

    Díaz, Alfonso; Galante, Eduardo; Favila, Mario E.

    2010-01-01

    Understanding the response of species to anthropogenic landscape modification is essential to design effective conservation programs. Recently, insects have been used in empirical studies to evaluate the impact of habitat modification and landscape fragmentation on biological diversity because they are often affected rapidly by changes in land use. In this study, the use of the landscape matrix by dung and carrion beetles in a fragmented tropical rain forest in the Los Tuxtlas Biosphere Reserve was analyzed. Fragments of tropical rain forest, forest-pasture edges, pastures, isolated trees, living fences (trees connected with barbed wire) and barbed wire fences were studied both near and far from forest fragments. Forest fragments had the highest abundance values, but pastures had the highest dung and carrion beetle biomass. Habitat specificity was high for the beetles in the most dissimilar habitats. Forest fragments and forest-pasture edges had and shared the highest number of species, but they shared only two species with pastures, barbed wire fences and isolated trees. Only one forest species was found within living fences far from the forest fragments. However, approximately 37% of the forest species were caught within living fences near the forest fragments. Therefore, forest-pasture edges function as hard edges and prevent movement among forest fragments, but living fences seem to act as continuous habitat corridors when connected to forest fragments, allowing forest beetles to move between the fragments. Further studies are necessary to determine the minimum width of living fences necessary to provide good corridors for these beetles and other species. PMID:20673066

  4. Timber resource statistics for the north coast resource area of California, 1994. Forest Service resource bulletin

    SciTech Connect

    Waddell, K.L.; Bassett, P.M.

    1996-09-01

    This report is a summary of timber resource statistics for the North Coast Resource Area of California, which includes Del Norte, Humboldt, Mendocino, and Sonoma Counties. Data were collected by the Pacific Northwest Research Station as part of a State wide multiresource inventory. The inventory sampled private and public lands except reserved areas and National Forests. The National Forest System provided data from regional inventories of North Coast National Forests. Area information for parks and other reserves was obtained directly from the organizations managing these areas. Statistical tables summarize all ownerships and provide estimates of land area, timber volume, growth, mortality, and harvest. Estimates of periodic change of volume and area on timber land are presented for all ownerships outside National Forests.

  5. Landscape fragmentation, severe drought, and the new Amazon forest fire regime.

    PubMed

    Alencar, Ane A; Brando, Paulo M; Asner, Gregory P; Putz, Francis E

    2015-09-01

    Changes in weather and land use are transforming the spatial and temporal characteristics of fire regimes in Amazonia, with important effects on the functioning of dense (i.e., closed-canopy), open-canopy, and transitional forests across the Basin. To quantify, document, and describe the characteristics and recent changes in forest fire regimes, we sampled 6 million ha of these three representative forests of the eastern and southern edges of the Amazon using 24 years (1983-2007) of satellite-derived annual forest fire scar maps and 16 years of monthly hot pixel information (1992-2007). Our results reveal that changes in forest fire regime properties differentially affected these three forest types in terms of area burned and fire scar size, frequency, and seasonality. During the study period, forest fires burned 15% (0.3 million ha), 44% (1 million ha), and 46% (0.6 million ha) of dense, open, and transitional forests, respectively. Total forest area burned and fire scar size tended to increase over time (even in years of average rainfall in open canopy and transitional forests). In dense forests, most of the temporal variability in fire regime properties was linked to El Nino Southern Oscillation (ENSO)-related droughts. Compared with dense forests, transitional and open forests experienced fires twice as frequently, with at least 20% of these forests' areas burning two or more times during the 24-year study period. Open and transitional forests also experienced higher deforestation rates than dense forests. During drier years, the end of the dry season was delayed by about a month, which resulted in larger burn scars and increases in overall area burned later in the season. These observations suggest that climate-mediated forest flammability is enhanced by landscape fragmentation caused by deforestation, as observed for open and transitional forests in the Eastern portion of the Amazon Basin.

  6. Effects of forest fragmentation on brood parasitism and nest predation in eastern and western landscapes

    USGS Publications Warehouse

    Cavitt, J.F.; Martin, T.E.

    2002-01-01

    The fragmentation of North American forests by agriculture and other human activities may negatively impact the demographic processes of birds through increases in nest predation and brood parasitism. In fact, the effects of fragmentation on demographic processes are thought to be a major underlying cause of long-term population declines of many bird species. However, much of our understanding of the demographic consequences of fragmentation has come from research conducted in North America east of the Rocky Mountains. Thus, results obtained from these studies may not be applicable to western landscapes, where habitats are often naturally heterogeneous due to topographic variation and periodic fire. We utilized data from a large database of nest records (>10,000) collected at sites both east and west of the Rocky Mountains to determine if the effects of fragmentation are consistent across broad geographic regions. We found that forest fragmentation tended to increase the frequency of brood parasitism by Brown-headed Cowbirds (Molothrus ater) east of the Rockies but we were unable to detect a significant difference in the West. Within the eastern United States, nest predation rates were consistently higher within fragmented sites relative to unfragmented sites. Yet, in the West, fragmentation resulted in a decrease in nest predation relative to unfragmented sites. This is perhaps accounted for by differential responses of the local predator community to fragmentation. Our results suggest that the effects of fragmentation may not be consistent across broad geographic regions and that the effects of fragmentation may depend on dynamics within local landscapes.

  7. Multiple successional pathways in human-modified tropical landscapes: new insights from forest succession, forest fragmentation and landscape ecology research.

    PubMed

    Arroyo-Rodríguez, Víctor; Melo, Felipe P L; Martínez-Ramos, Miguel; Bongers, Frans; Chazdon, Robin L; Meave, Jorge A; Norden, Natalia; Santos, Bráulio A; Leal, Inara R; Tabarelli, Marcelo

    2017-02-01

    Old-growth tropical forests are being extensively deforested and fragmented worldwide. Yet forest recovery through succession has led to an expansion of secondary forests in human-modified tropical landscapes (HMTLs). Secondary forests thus emerge as a potential repository for tropical biodiversity, and also as a source of essential ecosystem functions and services in HMTLs. Such critical roles are controversial, however, as they depend on successional, landscape and socio-economic dynamics, which can vary widely within and across landscapes and regions. Understanding the main drivers of successional pathways of disturbed tropical forests is critically needed for improving management, conservation, and restoration strategies. Here, we combine emerging knowledge from tropical forest succession, forest fragmentation and landscape ecology research to identify the main driving forces shaping successional pathways at different spatial scales. We also explore causal connections between land-use dynamics and the level of predictability of successional pathways, and examine potential implications of such connections to determine the importance of secondary forests for biodiversity conservation in HMTLs. We show that secondary succession (SS) in tropical landscapes is a multifactorial phenomenon affected by a myriad of forces operating at multiple spatio-temporal scales. SS is relatively fast and more predictable in recently modified landscapes and where well-preserved biodiversity-rich native forests are still present in the landscape. Yet the increasing variation in landscape spatial configuration and matrix heterogeneity in landscapes with intermediate levels of disturbance increases the uncertainty of successional pathways. In landscapes that have suffered extensive and intensive human disturbances, however, succession can be slow or arrested, with impoverished assemblages and reduced potential to deliver ecosystem functions and services. We conclude that: (i

  8. Changes in Tree Reproductive Traits Reduce Functional Diversity in a Fragmented Atlantic Forest Landscape

    PubMed Central

    Girão, Luciana Coe; Lopes, Ariadna Valentina; Tabarelli, Marcelo; Bruna, Emilio M.

    2007-01-01

    Functional diversity has been postulated to be critical for the maintenance of ecosystem functioning, but the way it can be disrupted by human-related disturbances remains poorly investigated. Here we test the hypothesis that habitat fragmentation changes the relative contribution of tree species within categories of reproductive traits (frequency of traits) and reduces the functional diversity of tree assemblages. The study was carried out in an old and severely fragmented landscape of the Brazilian Atlantic forest. We used published information and field observations to obtain the frequency of tree species and individuals within 50 categories of reproductive traits (distributed in four major classes: pollination systems, floral biology, sexual systems, and reproductive systems) in 10 fragments and 10 tracts of forest interior (control plots). As hypothesized, populations in fragments and control plots differed substantially in the representation of the four major classes of reproductive traits (more than 50% of the categories investigated). The most conspicuous differences were the lack of three pollination systems in fragments-pollination by birds, flies and non-flying mammals-and that fragments had a higher frequency of both species and individuals pollinated by generalist vectors. Hermaphroditic species predominate in both habitats, although their relative abundances were higher in fragments. On the contrary, self-incompatible species were underrepresented in fragments. Moreover, fragments showed lower functional diversity (H' scores) for pollination systems (−30.3%), floral types (−23.6%), and floral sizes (−20.8%) in comparison to control plots. In contrast to the overwhelming effect of fragmentation, patch and landscape metrics such as patch size and forest cover played a minor role on the frequency of traits. Our results suggest that habitat fragmentation promotes a marked shift in the relative abundance of tree reproductive traits and greatly

  9. Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela

    USGS Publications Warehouse

    Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.; Bird, David M.; Varland, Daniel E.; Negro, Juan Jose

    1996-01-01

    The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 42 species of diurnal raptors observed in affected areas in this region. We observed some raptors considered as forest interior species and other open country species foraging and roosting in man-made openings inside the forest.

  10. Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela

    USGS Publications Warehouse

    Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.

    1994-01-01

    The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 40 species of diurnal raptors observed in ten affected areas, including raptors considered as forest interior species and some open country species utilizing the man-made openings inside the forest for roosting and foraging.

  11. Impacts of changes in land use and fragmentation patterns on Atlantic coastal forests in northern Spain.

    PubMed

    Teixido, Alberto L; Quintanilla, Luis G; Carreño, Francisco; Gutiérrez, David

    2010-01-01

    Changes in forested landscapes may have important consequences for ecosystem services and biodiversity conservation. In northern Spain, major changes in land use occurred during the second half of the 20th century, but their impacts on forests have not been quantified. We evaluated the dynamics of landscape and forest distribution patterns between 1957 and 2003 in Fragas do Eume Natural Park (northwestern Spain). We used orthoimages and a set of standard landscape metrics to determine transitions between land cover classes and to examine forest distribution patterns. Eucalypt plantations showed the greatest increase in area (197%) over time. Furthermore, transitions to eucalypt plantations were found in all major land cover classes. Forest showed a net decline of 20% in total area and represented 30% of the landscape area in 2003. Forest losses were mainly due to eucalypt plantations and the building of a water reservoir, while forest gains were due to increases in shrubland, meadows and cultivated fields which had been recolonised. Forest patch size and core area decreased, and edge length increased over time. In turn, increases were obtained in mean distance between forest patches, and in adjacency to eucalypt plantations and to a water reservoir. These results suggest an increase in forest fragmentation from 1957 to 2003, as well as a change in the nature of the habitat surrounding forest patches. This study shows that land use changes, mostly from eucalypt plantation intensification, negatively affected forested habitats, although some regeneration was ongoing through ecological succession from land abandonment.

  12. Mammal assemblages in forest fragments and landscapes occupied by black howler monkeys.

    PubMed

    Rangel-Negrín, Ariadna; Coyohua-Fuentes, Alejandro; Canales-Espinosa, Domingo; Dias, Pedro Américo D

    2014-07-01

    Species assemblages in disturbed habitats vary as a function of the interaction between species requirements and the spatial configuration of the habitat. There are many reports accounting for the presence of howler monkeys in fragments where other mammals are absent, suggesting that they are more resilient. In the present study we explored this idea and predicted that if howler monkeys were more resilient to habitat loss and fragmentation than other mammals, mammal assemblages in fragments occupied by howler monkeys should include fewer species with decreasing amount of habitat (smaller fragment size and less habitat in the landscape) and increasing number of forest fragments. We explored these relationships by additionally considering the feeding and life habits of mammal species, as well as the isolation and proximity of each fragment to human settlements and roads. We sampled the presence of mammals in five fragments occupied by black howler monkeys (Alouatta pigra) in the Mexican state of Campeche. Through direct sights performed during 240 h in each fragment, we observed 23 species. At the landscape scale, higher fragmentation was associated with a decrease in herbivores, omnivores and total number of species. At the fragment scale semiarboreal, omnivore, and total number of species increased with increasing fragment size. This study supports the idea that howler monkeys are more resilient to forest loss and fragmentation than other native mammals, and our exploratory analyses suggest that the specific mammal assemblages that are found in fragments are related to both landscape and fragment scale spatial attributes, as well as with species-specific characteristics.

  13. The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants.

    PubMed

    Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

    2016-01-01

    Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages.

  14. The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants

    PubMed Central

    Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

    2016-01-01

    Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages. PMID:26731271

  15. Deforestation and Forest Fragmentation in South Ecuador since the 1970s - Losing a Hotspot of Biodiversity.

    PubMed

    Tapia-Armijos, María Fernanda; Homeier, Jürgen; Espinosa, Carlos Iván; Leuschner, Christoph; de la Cruz, Marcelino

    2015-01-01

    Deforestation and fragmentation are major components of global change; both are contributing to the rapid loss of tropical forest area with important implications for ecosystem functioning and biodiversity conservation. The forests of South Ecuador are a biological 'hotspot' due to their high diversity and endemism levels. We examined the deforestation and fragmentation patterns in this area of high conservation value using aerial photographs and Aster satellite scenes. The registered annual deforestation rates of 0.75% (1976-1989) and 2.86% (1989-2008) for two consecutive survey periods, the decreasing mean patch size and the increasing isolation of the forest fragments show that the area is under severe threat. Approximately 46% of South Ecuador's original forest cover had been converted by 2008 into pastures and other anthropogenic land cover types. We found that deforestation is more intense at lower elevations (premontane evergreen forest and shrubland) and that the deforestation front currently moves in upslope direction. Improved awareness of the spatial extent, dynamics and patterns of deforestation and forest fragmentation is urgently needed in biologically diverse areas like South Ecuador.

  16. Human impacts affect tree community features of 20 forest fragments of a vanishing neotropical hotspot.

    PubMed

    Pereira, José Aldo Alves; de Oliveira-Filho, Ary Teixeira; Eisenlohr, Pedro V; Miranda, Pedro L S; de Lemos Filho, José Pires

    2015-02-01

    The loss in forest area due to human occupancy is not the only threat to the remaining biodiversity: forest fragments are susceptible to additional human impact. Our aim was to investigate the effect of human impact on tree community features (species composition and abundance, and structural descriptors) and check if there was a decrease in the number of slender trees, an increase in the amount of large trees, and also a reduction in the number of tree species that occur in 20 fragments of Atlantic montane semideciduous forest in southeastern Brazil. We produced digital maps of each forest fragment using Landsat 7 satellite images and processed the maps to obtain morphometric variables. We used investigative questionnaires and field observations to survey the history of human impact. We then converted the information into scores given to the extent, severity, and duration of each impact, including proportional border area, fire, trails, coppicing, logging, and cattle, and converted these scores into categorical levels. We used linear models to assess the effect of impacts on tree species abundance distribution and stand structural descriptors. Part of the variation in floristic patterns was significantly correlated to the impacts of fire, logging, and proportional border area. Structural descriptors were influenced by cattle and outer roads. Our results provided, for the first time, strong evidence that tree species occurrence and abundance, and forest structure of Atlantic seasonal forest fragments respond differently to various modes of disturbance by humans.

  17. Human Impacts Affect Tree Community Features of 20 Forest Fragments of a Vanishing Neotropical Hotspot

    NASA Astrophysics Data System (ADS)

    Pereira, José Aldo Alves; de Oliveira-Filho, Ary Teixeira; Eisenlohr, Pedro V.; Miranda, Pedro L. S.; de Lemos Filho, José Pires

    2015-02-01

    The loss in forest area due to human occupancy is not the only threat to the remaining biodiversity: forest fragments are susceptible to additional human impact. Our aim was to investigate the effect of human impact on tree community features (species composition and abundance, and structural descriptors) and check if there was a decrease in the number of slender trees, an increase in the amount of large trees, and also a reduction in the number of tree species that occur in 20 fragments of Atlantic montane semideciduous forest in southeastern Brazil. We produced digital maps of each forest fragment using Landsat 7 satellite images and processed the maps to obtain morphometric variables. We used investigative questionnaires and field observations to survey the history of human impact. We then converted the information into scores given to the extent, severity, and duration of each impact, including proportional border area, fire, trails, coppicing, logging, and cattle, and converted these scores into categorical levels. We used linear models to assess the effect of impacts on tree species abundance distribution and stand structural descriptors. Part of the variation in floristic patterns was significantly correlated to the impacts of fire, logging, and proportional border area. Structural descriptors were influenced by cattle and outer roads. Our results provided, for the first time, strong evidence that tree species occurrence and abundance, and forest structure of Atlantic seasonal forest fragments respond differently to various modes of disturbance by humans.

  18. Sequential Fragmentation of Pleistocene Forests in an East Africa Biodiversity Hotspot: Chameleons as a Model to Track Forest History

    PubMed Central

    Measey, G. John; Tolley, Krystal A.

    2011-01-01

    Background The Eastern Arc Mountains (EAM) is an example of naturally fragmented tropical forests, which contain one of the highest known concentrations of endemic plants and vertebrates. Numerous paleo-climatic studies have not provided direct evidence for ancient presence of Pleistocene forests, particularly in the regions in which savannah presently occurs. Knowledge of the last period when forests connected EAM would provide a sound basis for hypothesis testing of vicariance and dispersal models of speciation. Dated phylogenies have revealed complex patterns throughout EAM, so we investigated divergence times of forest fauna on four montane isolates in close proximity to determine whether forest break-up was most likely to have been simultaneous or sequential, using population genetics of a forest restricted arboreal chameleon, Kinyongia boehmei. Methodology/Principal Findings We used mitochondrial and nuclear genetic sequence data and mutation rates from a fossil-calibrated phylogeny to estimate divergence times between montane isolates using a coalescent approach. We found that chameleons on all mountains are most likely to have diverged sequentially within the Pleistocene from 0.93–0.59 Ma (95% HPD 0.22–1.84 Ma). In addition, post-hoc tests on chameleons on the largest montane isolate suggest a population expansion ∼182 Ka. Conclusions/Significance Sequential divergence is most likely to have occurred after the last of three wet periods within the arid Plio-Pleistocene era, but was not correlated with inter-montane distance. We speculate that forest connection persisted due to riparian corridors regardless of proximity, highlighting their importance in the region's historic dispersal events. The population expansion coincides with nearby volcanic activity, which may also explain the relative paucity of the Taita's endemic fauna. Our study shows that forest chameleons are an apposite group to track forest fragmentation, with the inference that forest

  19. Factors affecting bird richness in a fragmented cork oak forest in Morocco

    NASA Astrophysics Data System (ADS)

    Cherkaoui, Imad; Selmi, Slaheddine; Boukhriss, Jihen; Hamid, Rguibi-Idrissi; Mohammed, Dakki

    2009-03-01

    The cork oak forest of Ma'amora in north-western Morocco was the largest cork oak forest in the world until the beginning of the 20th century. Due to growing land use for agriculture and urbanization, however, this forest has become fragmented into relatively small and isolated patches. The effects of this fragmentation on the diversity of wild animal communities have never been investigated despite the importance of such investigations in elaborating long-term conservation plans of the biodiversity of this forest system. In this study of a sample of 44 forest patches we assessed the relationships between species numbers of wintering, breeding and spring migrant birds and patch size, shape, isolation and vegetation structure. We found that species richnesses of the three studied bird assemblages were strongly related to local vegetation structure, namely to the diversity and abundance of trees and bushes. Patches with higher diversity and cover of trees and bushes support higher numbers of bird species. However, patch size, shape and isolation were not significant predictors of bird richness. These results suggest that bird communities in the studied forest patches were more likely shaped by local habitat suitability rather than the amount of habitat or patch isolation. The results also demonstrate negative effects of current human pressures, namely logging, grazing and disturbance, on the diversity of bird communities in this forest system. This emphasizes the need for urgent management efforts aiming at reducing the negative impacts of forest use by humans on bird diversity in this forest system.

  20. Restricted pollen flow of Dieffenbachia seguine populations in fragmented and continuous tropical forest.

    PubMed

    Cuartas-Hernández, S; Núñez-Farfán, J; Smouse, P E

    2010-08-01

    Habitat fragmentation can change the ecological context of populations, rupturing genetic connectivity among them, changing genetic structure, and increasing the loss of genetic diversity. We analyzed mating system and pollen structure in two population fragments and two continuous forest populations of Dieffenbachia seguine (Araceae), an insect-pollinated understory herb in the tropical rain forest of Los Tuxtlas, México, using nine allozyme loci. Mating system analysis indicated almost complete outcrossing but some inbreeding among the adults. Pollen structure analysis indicated highly restricted pollen flow, both within and among populations. We showed that the effective pollination neighborhood was small in all populations, and slightly (though not significantly) smaller in fragments, partially as a consequence of an increase in density of reproductive individuals in those fragments. Using assignment analysis, we showed that all populations were strongly structured, suggesting that pollen and seed flow across the Los Tuxtlas landscape has been spatially restricted, though sufficient to maintain connectedness. Forest fragmentation at Los Tuxtlas has (so far) had limited impact on pollen dynamics, despite the changing ecological context, with reduced pollinator abundance being partially offset by increased flowering density in fragments. Continued outcrossing and limited pollen immigration, coupled with more extensive seed migration, should maintain genetic connectedness in D. seguine, if fragmentation is not further exacerbated by additional deforestation.

  1. Effects of forest fragmentation on nocturnal Asian birds: A case study from Xishuangbanna, China

    PubMed Central

    DAYANANDA, Salindra K.; GOODALE, Eben; LEE, Myung-bok; LIU, Jia-Jia; MAMMIDES, Christos; PASION, Bonifacio O.; QUAN, Rui-Chang; SLIK, J. W. Ferry; SREEKAR, Rachakonda; TOMLINSON, Kyle W.; YASUDA, Mika

    2016-01-01

    Owls have the potential to be keystone species for conservation in fragmented landscapes, as the absence of these predators could profoundly change community structure. Yet few studies have examined how whole communities of owls respond to fragmentation, especially in the tropics. When evaluating the effect of factors related to fragmentation, such as fragment area and distance to the edge, on these birds, it is also important in heterogeneous landscapes to ask how ‘location factors’ such as the topography, vegetation and soil of the fragment predict their persistence. In Xishuangbanna, southwest China, we established 43 transects (200 m×60 m) within 20 forest fragments to sample nocturnal birds, both visually and aurally. We used a multimodel inference approach to identify the factors that influence owl species richness, and generalized linear mixed models to predict the occurrence probabilities of each species. We found that fragmentation factors dominated location factors, with larger fragments having more species, and four of eight species were significantly more likely to occur in large fragments. Given the potential importance of these birds on regulating small mammal and other animal populations, and thus indirectly affecting seed dispersal, we suggest further protection of large fragments and programs to increase their connectivity to the remaining smaller fragments. PMID:27265653

  2. Pilot survey of avahi population (woolly lemurs) in littoral forest fragments of southeast Madagascar.

    PubMed

    Norscia, Ivan

    2008-01-01

    This study presents a pilot survey of the avahis (pair-living, nocturnal prosimians) living in threatened littoral forest fragments of southeastern Madagascar. In the period of October-December 2004, I evaluated the density of adult and newborn avahis (carried by the mothers) by counting the individuals encountered during 58 night walks in seven fragments of Sainte Luce and Mandena forests, along one trail/fragment. Along each trail, I used random plots (5 m2) for a preliminary characterization of the vegetation. The density of the population was not correlated with fragment size and number of plant morphospecies, while it was correlated with large tree availability. Possibly due to a low energy diet based on leaves and to specialized and energetically expensive vertical leaping, the loss of large trees by selective logging seems to affect avahi populations more than other variables.

  3. High resolution analysis of tropical forest fragmentation and its impact on the global carbon cycle

    PubMed Central

    Brinck, Katharina; Fischer, Rico; Groeneveld, Jürgen; Lehmann, Sebastian; Dantas De Paula, Mateus; Pütz, Sandro; Sexton, Joseph O.; Song, Danxia; Huth, Andreas

    2017-01-01

    Deforestation in the tropics is not only responsible for direct carbon emissions but also extends the forest edge wherein trees suffer increased mortality. Here we combine high-resolution (30 m) satellite maps of forest cover with estimates of the edge effect and show that 19% of the remaining area of tropical forests lies within 100 m of a forest edge. The tropics house around 50 million forest fragments and the length of the world's tropical forest edges sums to nearly 50 million km. Edge effects in tropical forests have caused an additional 10.3 Gt (2.1–14.4 Gt) of carbon emissions, which translates into 0.34 Gt per year and represents 31% of the currently estimated annual carbon releases due to tropical deforestation. Fragmentation substantially augments carbon emissions from tropical forests and must be taken into account when analysing the role of vegetation in the global carbon cycle. PMID:28303883

  4. High resolution analysis of tropical forest fragmentation and its impact on the global carbon cycle.

    PubMed

    Brinck, Katharina; Fischer, Rico; Groeneveld, Jürgen; Lehmann, Sebastian; Dantas De Paula, Mateus; Pütz, Sandro; Sexton, Joseph O; Song, Danxia; Huth, Andreas

    2017-03-17

    Deforestation in the tropics is not only responsible for direct carbon emissions but also extends the forest edge wherein trees suffer increased mortality. Here we combine high-resolution (30 m) satellite maps of forest cover with estimates of the edge effect and show that 19% of the remaining area of tropical forests lies within 100 m of a forest edge. The tropics house around 50 million forest fragments and the length of the world's tropical forest edges sums to nearly 50 million km. Edge effects in tropical forests have caused an additional 10.3 Gt (2.1-14.4 Gt) of carbon emissions, which translates into 0.34 Gt per year and represents 31% of the currently estimated annual carbon releases due to tropical deforestation. Fragmentation substantially augments carbon emissions from tropical forests and must be taken into account when analysing the role of vegetation in the global carbon cycle.

  5. Corridors restore animal-mediated pollination in fragmented tropical forest landscapes

    PubMed Central

    Kormann, Urs; Scherber, Christoph; Tscharntke, Teja; Klein, Nadja; Larbig, Manuel; Valente, Jonathon J.; Hadley, Adam S.; Betts, Matthew G.

    2016-01-01

    Tropical biodiversity and associated ecosystem functions have become heavily eroded through habitat loss. Animal-mediated pollination is required in more than 94% of higher tropical plant species and 75% of the world's leading food crops, but it remains unclear if corridors avert deforestation-driven pollination breakdown in fragmented tropical landscapes. Here, we used manipulative resource experiments and field observations to show that corridors functionally connect neotropical forest fragments for forest-associated hummingbirds and increase pollen transfer. Further, corridors boosted forest-associated pollinator availability in fragments by 14.3 times compared with unconnected equivalents, increasing overall pollination success. Plants in patches without corridors showed pollination rates equal to bagged control flowers, indicating pollination failure in isolated fragments. This indicates, for the first time, that corridors benefit tropical forest ecosystems beyond boosting local species richness, by functionally connecting mutualistic network partners. We conclude that small-scale adjustments to landscape configuration safeguard native pollinators and associated pollination services in tropical forest landscapes. PMID:26817765

  6. Corridors restore animal-mediated pollination in fragmented tropical forest landscapes.

    PubMed

    Kormann, Urs; Scherber, Christoph; Tscharntke, Teja; Klein, Nadja; Larbig, Manuel; Valente, Jonathon J; Hadley, Adam S; Betts, Matthew G

    2016-01-27

    Tropical biodiversity and associated ecosystem functions have become heavily eroded through habitat loss. Animal-mediated pollination is required in more than 94% of higher tropical plant species and 75% of the world's leading food crops, but it remains unclear if corridors avert deforestation-driven pollination breakdown in fragmented tropical landscapes. Here, we used manipulative resource experiments and field observations to show that corridors functionally connect neotropical forest fragments for forest-associated hummingbirds and increase pollen transfer. Further, corridors boosted forest-associated pollinator availability in fragments by 14.3 times compared with unconnected equivalents, increasing overall pollination success. Plants in patches without corridors showed pollination rates equal to bagged control flowers, indicating pollination failure in isolated fragments. This indicates, for the first time, that corridors benefit tropical forest ecosystems beyond boosting local species richness, by functionally connecting mutualistic network partners. We conclude that small-scale adjustments to landscape configuration safeguard native pollinators and associated pollination services in tropical forest landscapes.

  7. Spatiotemporal dynamics of forest fragmentation and its potential implications for carbon dynamics in the Brazilian Amazon between 2001 and 2010

    NASA Astrophysics Data System (ADS)

    Numata, I.; Cochrane, M.

    2012-12-01

    Vast tracts of Amazonian tropical rain forest have been converted to human land uses in recent decades as regional development proceeds. Large losses of forest cover are exacerbated because remaining forests are fragmented into smaller habitats. The current basin-wide status and implications of forest fragmentation on remnant forests and regional carbon dynamics are not well known. We performed a regional forest fragmentation analysis for the entire Brazilian Amazon between 2001 and 2010 using INPE PRODES data. During the past decade, the number of forest fragments doubled, nearly 125,000 fragments were formed, with more than 50% being smaller than 10 ha. Forest edges increased by 36,335 km/year on average over the study period. However, the rate was much greater from 2001-2005 (50,046 km/year) than 2006-2010 (25,365 km/year) when deforestation rates dropped drastically. In 2010, 55% of basin-wide forest edges were < 10 years old as a result of the creation of small forest fragments where intensive biological and ecological degradation is ongoing. We estimate that biomass collapse-related carbon fluxes from forests within100m of edges were between 126-221 Tg C for 2001-2010 in the Brazilian Amazon. Edge-released carbon accounted for 2.6-4.5% of deforestation-related carbon emissions. However, the relative importance of carbon emissions from forest fragmentation varied according to annual deforestation rates and increased from 1.7-3.0% to 3.3-5.6% of the respective deforestation emissions in 2001-2005 and 2006-2010, respectively. As of 2010, 17% of Amazonian forests are within 1km of forest edges, making them easily accessible and vulnerable to degradation. On the other hand, 51% of remaining forests across the basin are within protected areas and only 1.5% has been deforested within 1 km of a forest edge, while, unprotected forests, 1km-edge forests averaged 34% deforestation. The state of Rondônia, where 95% of unprotected forests are within 1km of edges in 2010

  8. Calibrating and testing a gap model for simulating forest management in the Oregon Coast Range

    USGS Publications Warehouse

    Pabst, R.J.; Goslin, M.N.; Garman, S.L.; Spies, T.A.

    2008-01-01

    The complex mix of economic and ecological objectives facing today's forest managers necessitates the development of growth models with a capacity for simulating a wide range of forest conditions while producing outputs useful for economic analyses. We calibrated the gap model ZELIG to simulate stand-level forest development in the Oregon Coast Range as part of a landscape-scale assessment of different forest management strategies. Our goal was to incorporate the predictive ability of an empirical model with the flexibility of a forest succession model. We emphasized the development of commercial-aged stands of Douglas-fir, the dominant tree species in the study area and primary source of timber. In addition, we judged that the ecological approach of ZELIG would be robust to the variety of other forest conditions and practices encountered in the Coast Range, including mixed-species stands, small-scale gap formation, innovative silvicultural methods, and reserve areas where forests grow unmanaged for long periods of time. We parameterized the model to distinguish forest development among two ecoregions, three forest types and two site productivity classes using three data sources: chronosequences of forest inventory data, long-term research data, and simulations from an empirical growth-and-yield model. The calibrated model was tested with independent, long-term measurements from 11 Douglas-fir plots (6 unthinned, 5 thinned), 3 spruce-hemlock plots, and 1 red alder plot. ZELIG closely approximated developmental trajectories of basal area and large trees in the Douglas-fir plots. Differences between simulated and observed conifer basal area for these plots ranged from -2.6 to 2.4 m2/ha; differences in the number of trees/ha ???50 cm dbh ranged from -8.8 to 7.3 tph. Achieving these results required the use of a diameter-growth multiplier, suggesting some underlying constraints on tree growth such as the temperature response function. ZELIG also tended to overestimate

  9. Forest Fragmentation and Landscape Transformation in a Reindeer Husbandry Area in Sweden

    NASA Astrophysics Data System (ADS)

    Kivinen, Sonja; Berg, Anna; Moen, Jon; Östlund, Lars; Olofsson, Johan

    2012-02-01

    Reindeer husbandry and forestry are two main land users in boreal forests in northern Sweden. Modern forestry has numerous negative effects on the ground-growing and arboreal lichens that are crucial winter resources for reindeer husbandry. Using digitized historical maps, we examined changes in the forest landscape structure during the past 100 years, and estimated corresponding changes in suitability of forest landscape mosaics for the reindeer winter grazing. Cover of old coniferous forests, a key habitat type of reindeer herding system, showed a strong decrease during the study period, whereas clear-cutting and young forests increased rapidly in the latter half of the 20th century. The dominance of young forests and fragmentation of old-growth forests (decreased patch sizes and increased isolation) reflect decreased amount of arboreal lichens as well as a lowered ability of the landscape to sustain long-term persistence of lichens. The results further showed that variation in ground lichen cover among sites was mainly related to soil moisture conditions, recent disturbances, such as soil scarification and prescribed burning, and possibly also to forest history. In general, the results suggest that the composition and configuration of the forest landscape mosaic has become less suitable for sustainable reindeer husbandry.

  10. Forest fragmentation and landscape transformation in a reindeer husbandry area in Sweden.

    PubMed

    Kivinen, Sonja; Berg, Anna; Moen, Jon; Ostlund, Lars; Olofsson, Johan

    2012-02-01

    Reindeer husbandry and forestry are two main land users in boreal forests in northern Sweden. Modern forestry has numerous negative effects on the ground-growing and arboreal lichens that are crucial winter resources for reindeer husbandry. Using digitized historical maps, we examined changes in the forest landscape structure during the past 100 years, and estimated corresponding changes in suitability of forest landscape mosaics for the reindeer winter grazing. Cover of old coniferous forests, a key habitat type of reindeer herding system, showed a strong decrease during the study period, whereas clear-cutting and young forests increased rapidly in the latter half of the 20th century. The dominance of young forests and fragmentation of old-growth forests (decreased patch sizes and increased isolation) reflect decreased amount of arboreal lichens as well as a lowered ability of the landscape to sustain long-term persistence of lichens. The results further showed that variation in ground lichen cover among sites was mainly related to soil moisture conditions, recent disturbances, such as soil scarification and prescribed burning, and possibly also to forest history. In general, the results suggest that the composition and configuration of the forest landscape mosaic has become less suitable for sustainable reindeer husbandry.

  11. Geotechnology and landscape ecology applied to the selection of potential forest fragments for seed harvesting.

    PubMed

    Santos, Alexandre Rosa Dos; Antonio Alvares Soares Ribeiro, Carlos; de Oliveira Peluzio, Telma Machado; Esteves Peluzio, João Batista; de Queiroz, Vagner Tebaldi; Figueira Branco, Elvis Ricardo; Lorenzon, Alexandre Simões; Domingues, Getulio Fonseca; Marcatti, Gustavo Eduardo; de Castro, Nero Lemos Martins; Teixeira, Thaisa Ribeiro; Dos Santos, Gleissy Mary Amaral Dino Alves; Santos Mota, Pedro Henrique; Ferreira da Silva, Samuel; Vargas, Rozimelia; de Carvalho, José Romário; Macedo, Leandro Levate; da Silva Araújo, Cintia; de Almeida, Samira Luns Hatum

    2016-12-01

    The Atlantic Forest biome is recognized for its biodiversity and is one of the most threatened biomes on the planet, with forest fragmentation increasing due to uncontrolled land use, land occupation, and population growth. The most serious aspect of the forest fragmentation process is the edge effect and the loss of biodiversity. In this context, the aim of this study was to evaluate the dynamics of forest fragmentation and select potential forest fragments with a higher degree of conservation for seed harvesting in the Itapemirim river basin, Espírito Santo State, Brazil. Image classification techniques, forest landscape ecology, and multi-criteria analysis were used to evaluate the evolution of forest fragmentation to develop the landscape metric indexes, and to select potential forest fragments for seed harvesting for the years 1985 and 2013. According to the results, there was a reduction of 2.55% of the occupancy of the fragments in the basin between the years 1985 and 2013. For the years 1985 and 2013, forest fragment units 2 and 3 were spatialized with a high potential for seed harvesting, representing 6.99% and 16.01% of the total fragments, respectively. The methodology used in this study has the potential to be used to support decisions for the selection of potential fragments for seed harvesting because selecting fragments in different environments by their spatial attributes provides a greater degree of conservation, contributing to the protection and conscious management of the forests. The proposed methodology can be adapted to other areas and different biomes of the world.

  12. Timber resource statistics for the central coast resource area of California. Forest Service resource bulletin

    SciTech Connect

    Waddell, K.L.; Bassett, P.M.

    1997-03-01

    This report is a summary of timber resource statistics for the Central Coast Resource Area of California, which includes Alameda, Contra Costa, Marin, Monterey, San Benito, San Francisco, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Solano, and Ventura Counties. Data were collected as part of a state-wide multiresource inventory. The inventory sampled private and public lands except reserved areas and National Forests. The national Forest System provided data from regional inventories of the Los Padres National Forest. Area information for parks and other reserves was obtained directly from the organizations managing these areas. Statistical tables summarize all ownerships and provide estimates of land area, timber volume, growth, mortality, and harvest. Estimates of period change of timberland area and timber volume are presented for all ownerships outside National Forests.

  13. Hurricane Katrina's carbon footprint on U.S. Gulf Coast forests.

    PubMed

    Chambers, Jeffrey Q; Fisher, Jeremy I; Zeng, Hongcheng; Chapman, Elise L; Baker, David B; Hurtt, George C

    2007-11-16

    Hurricane Katrina's impact on U.S. Gulf Coast forests was quantified by linking ecological field studies, Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS) image analyses, and empirically based models. Within areas affected by relatively constant wind speed, tree mortality and damage exhibited strong species-controlled gradients. Spatially explicit forest disturbance maps coupled with extrapolation models predicted mortality and severe structural damage to approximately 320 million large trees totaling 105 teragrams of carbon, representing 50 to 140% of the net annual U.S. forest tree carbon sink. Changes in disturbance regimes from increased storm activity expected under a warming climate will reduce forest biomass stocks, increase ecosystem respiration, and may represent an important positive feedback mechanism to elevated atmospheric carbon dioxide.

  14. A National Assessment of Forest Fragmentation Change for the Conterminous United States

    EPA Science Inventory

    Determination of land-cover change is important for ecological assessments and environmental planning. We used national land-cover change data, resolved at 0.09 ha per pixel, to assess change in forest fragmentation for the conterminous United States. Temporal change in fragmen...

  15. Landscape responses of bats to habitat fragmentation in Atlantic forest of paraguay

    USGS Publications Warehouse

    Gorresen, P.M.; Willig, M.R.

    2004-01-01

    Understanding effects of habitat loss and fragmentation on populations or communities is critical to effective conservation and restoration. This is particularly important for bats because they provide vital services to ecosystems via pollination and seed dispersal, especially in tropical and subtropical habitats. Based on more than 1,000 h of survey during a 15-month period, we quantified species abundances and community structure of phyllostomid bats at 14 sites in a 3,000-km2 region of eastern Paraguay. Abundance was highest for Artibeus lituratus in deforested landscapes and for Chrotopterus auritus in forested habitats. In contrast, Artibeus fimbriatus, Carollia perspicillata, Glossophaga soricina, Platyrrhinus lineatus, Pygoderma bilabiatum, and Sturnira lilium attained highest abundance in moderately fragmented forest landscapes. Forest cover, patch size, and patch density frequently were associated with abundance of species. At the community level, species richness was highest in partly deforested landscapes, whereas evenness was greatest in forested habitat. In general, the highest diversity of bats occurred in landscapes comprising moderately fragmented forest habitat. This underscores the importance of remnant habitat patches to conservation strategies.

  16. Observed Differences in the Human Footprint and Forest Fragmentation in the Primary Forest Area of the Democratic Republic of Congo: A Remote Sensing Study for 2000-2010

    NASA Astrophysics Data System (ADS)

    Molinario, G.

    2015-12-01

    Conflict in the Democratic Republic of Congo (DRC) and neighboring countries has caused the displacement of people internally and internationally sometimes leading to drastic changes in the impact that traditional slash and burn shifting cultivation has on the forest ecosystem. In other areas, the lack of infrastructure and governance has isolated and protected areas of core forest from large scale exploitation. Observing specific patterns of forest fragmentation caused either by the expansion of existing rural complex areas or of isolated forest perforations has allowed us to track the differential growth of the human footprint throughout forested area of the country during the period 2000-2010. Our methodological approach involved the development of a model of shifting cultivation and forest fragmentation in which spatial rules applied morphological image processing to the Forets d'Afrique Central Evaluee par Teledetection (FACET) product. The result is a disaggregated classification of the primary forest into patch, edge, perforated, fragmented and core forest subtypes which we subsequently re-aggregated into homogenous anthropogenic macro-areas of rural complex and isolated forest perforations. We tracked how subsequent forest loss observed in 2005 and 2010 grew or shrunk these areas, presumably with differential impacts on the forest ecosystem. Using this approach we were able to map forest degradation by contextualizing the contribution of forest loss to change in different types of areas, highlighting how it can be greatly underestimated by a non contextualized per-pixel assessment of forest cover loss.

  17. Internal Habitat Quality Determines the Effects of Fragmentation on Austral Forest Climbing and Epiphytic Angiosperms

    PubMed Central

    Magrach, Ainhoa; Larrinaga, Asier R.; Santamaría, Luis

    2012-01-01

    Habitat fragmentation has become one of the major threats to biodiversity worldwide, particularly in the case of forests, which have suffered enormous losses during the past decades. We analyzed how changes in patch configuration and habitat quality derived from the fragmentation of austral temperate rainforests affect the distribution of six species of forest-dwelling climbing and epiphytic angiosperms. Epiphyte and vine abundance is primarily affected by the internal characteristics of patches (such as tree size, the presence of logging gaps or the proximity to patch edges) rather than patch and landscape features (such as patch size, shape or connectivity). These responses were intimately related to species-specific characteristics such as drought- or shade-tolerance. Our study therefore suggests that plant responses to fragmentation are contingent on both the species' ecology and the specific pathways through which the study area is being fragmented, (i.e. extensive logging that shaped the boundaries of current forest patches plus recent, unregulated logging that creates gaps within patches). Management practices in fragmented landscapes should therefore consider habitat quality within patches together with other spatial attributes at landscape or patch scales. PMID:23119096

  18. The nexus between forest fragmentation in Africa and Ebola virus disease outbreaks

    PubMed Central

    Rulli, Maria Cristina; Santini, Monia; Hayman, David T. S.; D’Odorico, Paolo

    2017-01-01

    Tropical forests are undergoing land use change in many regions of the world, including the African continent. Human populations living close to forest margins fragmented and disturbed by deforestation may be particularly exposed to zoonotic infections because of the higher likelihood for humans to be in contact with disease reservoirs. Quantitative analysis of the nexus between deforestation and the emergence of Ebola virus disease (EVD), however, is still missing. Here we use land cover change data in conjunction with EVD outbreak records to investigate the association between recent (2004–2014) outbreaks in West and Central Africa, and patterns of land use change in the region. We show how in these EVD outbreaks the index cases in humans (i.e. spillover from wildlife reservoirs) occurred mostly in hotspots of forest fragmentation. PMID:28195145

  19. The nexus between forest fragmentation in Africa and Ebola virus disease outbreaks

    NASA Astrophysics Data System (ADS)

    Rulli, Maria Cristina; Santini, Monia; Hayman, David T. S.; D’Odorico, Paolo

    2017-02-01

    Tropical forests are undergoing land use change in many regions of the world, including the African continent. Human populations living close to forest margins fragmented and disturbed by deforestation may be particularly exposed to zoonotic infections because of the higher likelihood for humans to be in contact with disease reservoirs. Quantitative analysis of the nexus between deforestation and the emergence of Ebola virus disease (EVD), however, is still missing. Here we use land cover change data in conjunction with EVD outbreak records to investigate the association between recent (2004–2014) outbreaks in West and Central Africa, and patterns of land use change in the region. We show how in these EVD outbreaks the index cases in humans (i.e. spillover from wildlife reservoirs) occurred mostly in hotspots of forest fragmentation.

  20. The nexus between forest fragmentation in Africa and Ebola virus disease outbreaks.

    PubMed

    Rulli, Maria Cristina; Santini, Monia; Hayman, David T S; D'Odorico, Paolo

    2017-02-14

    Tropical forests are undergoing land use change in many regions of the world, including the African continent. Human populations living close to forest margins fragmented and disturbed by deforestation may be particularly exposed to zoonotic infections because of the higher likelihood for humans to be in contact with disease reservoirs. Quantitative analysis of the nexus between deforestation and the emergence of Ebola virus disease (EVD), however, is still missing. Here we use land cover change data in conjunction with EVD outbreak records to investigate the association between recent (2004-2014) outbreaks in West and Central Africa, and patterns of land use change in the region. We show how in these EVD outbreaks the index cases in humans (i.e. spillover from wildlife reservoirs) occurred mostly in hotspots of forest fragmentation.

  1. Effects of forest fragmentation on phenological patterns and reproductive success of the tropical dry forest tree Ceiba aesculifolia.

    PubMed

    Herrerías-Diego, Yvonne; Quesada, Mauricio; Stoner, Kathryn E; Lobo, Jorge A

    2006-08-01

    Spatial isolation caused by forest fragmentation and temporal isolation caused by asynchronous flowering of plants have been proposed as important factors that affect the reproduction ofplant populations. In a 4-year study, we determined the effects of forest fragmentation and spatial isolation on flowering phenology and reproductive success of the tropical tree Ceiba aesculifolia ([Kunth] Britton & Rose). We conducted our study in the dry forest of Mexico and compared populations in two habitat conditions based on density and environmental conditions: (1) disturbed habitat (four populations of < or =3 reproductive individuals/ha surrounded by agriculturalfields or pastures) and (2) undisturbed habitat (three populations of groups of >6 reproductive individuals/ha surrounded by undisturbed mature forest). We compared the following variables within these populations over 4 years: flowering overlap, proportion of individuals with flowers and fruit, total flower production, total fruit production, fruit set, seed production, and seed abortion. Little overlap in flowering occurred among the populations in the two habitat conditions. The flowering period of trees in the disturbed habitat initiated between 15 to 20 days before the flowering period of trees in the undisturbed habitat during 3 years. Flowering of trees in the undisturbed habitat peaked at the end of the flowering period of the trees in the disturbed habitat. The proportion of trees that flowered was greater in the undisturbed habitat. Nevertheless, total flower production was greater in the disturbed habitat and these differences were maintained across 3 years. The proportion of individuals that produced fruit did not differ across habitat conditions but did differ across years. Total fruit production was greater in the disturbed habitat, but fruit set and seed production were the same across years and between habitat conditions. Seed abortion varied over years between habitats. We concluded that forest

  2. Effect of forest fragmentation on microsporogenesis and pollen viability in Eugenia uniflora, a tree native to the Atlantic Forest.

    PubMed

    de Almeida, D J; Faria, M V; da Silva, P R

    2012-12-06

    Habitat fragmentation, caused by the expansion of agriculture in natural areas, may be one of the strongest impacts humans have on the ecosystem. These changes can decrease the number of individuals in a population, leading to endogamy. In allogamous species, endogamy can have a negative effect on reproductive capacity. In this study, we analyzed the effects of forest fragmentation on microsporogenesis and pollen viability in Eugenia uniflora L., a tree species native to the Atlantic Forest. We analyzed 4 populations, 3 of which were connected by forest corridors and 1 of which was isolated by agricultural fields on all sides. For microsporogenesis analysis, 9000 meiocytes representing all stages of meiosis were evaluated. To perform the pollen viability test, we evaluated 152,000 pollen grains. Microsporogenesis was stable in plants from populations that were connected by forest corridors (abnormalities, less than 6%), while microsporogenesis in plants from the isolated population showed a higher level of abnormalities (13-29%). Average pollen viability was found to be more than 93% in the non-isolated populations and 82.62% in the isolated population. The χ(2) test showed that, in the isolated population, the meiotic index was significantly lower than that in the non-isolated populations (P = 0.03). The analysis of variance for the percentage of viable pollen grains confirmed the significant difference between the isolated and non-isolated populations. Our data show that forest fragmentation has a direct effect on microsporogenesis and pollen viability in E. uniflora and can directly influence the reproductive capacity of isolated populations of this species.

  3. Within and Among Patch Variability in Patterns of Insect Herbivory Across a Fragmented Forest Landscape

    PubMed Central

    Maguire, Dorothy Y.; Buddle, Christopher M.; Bennett, Elena M.

    2016-01-01

    Fragmentation changes the spatial patterns of landscapes in ways that can alter the flow of materials and species; however, our understanding of the consequences of this fragmentation and flow alteration for ecosystem processes and ecosystem services remains limited. As an ecological process that affects many ecosystem services and is sensitive to fragmentation, insect herbivory is a good model system for exploring the role of fragmentation, and the resulting spatial patterns of landscapes, in the provision of ecosystem services. To refine our knowledge of how changes in landscape pattern affect insect herbivory, we quantified the combined influence of among patch (patch area and patch connectivity) and within patch (location within patch; canopy, edge, interior) factors on amounts of insect herbivory in a fragmented forest landscape. We measured herbivory in 20 forest patches of differing size and connectivity in southern Quebec (Canada). Within each patch, herbivory was quantified at the interior, edge, and canopy of sugar maple trees during the spring and summer of 2011 and 2012. Results show that connectivity affects herbivory differently depending on the location within the patch (edge, interior, canopy), an effect that would have gone unnoticed if samples were pooled across locations. These results suggest considering structure at both the patch and within patch scales may help to elucidate patterns when studying the effects of fragmentation on ecosystem processes, with implications for the services they support. PMID:26938457

  4. Within and Among Patch Variability in Patterns of Insect Herbivory Across a Fragmented Forest Landscape.

    PubMed

    Maguire, Dorothy Y; Buddle, Christopher M; Bennett, Elena M

    2016-01-01

    Fragmentation changes the spatial patterns of landscapes in ways that can alter the flow of materials and species; however, our understanding of the consequences of this fragmentation and flow alteration for ecosystem processes and ecosystem services remains limited. As an ecological process that affects many ecosystem services and is sensitive to fragmentation, insect herbivory is a good model system for exploring the role of fragmentation, and the resulting spatial patterns of landscapes, in the provision of ecosystem services. To refine our knowledge of how changes in landscape pattern affect insect herbivory, we quantified the combined influence of among patch (patch area and patch connectivity) and within patch (location within patch; canopy, edge, interior) factors on amounts of insect herbivory in a fragmented forest landscape. We measured herbivory in 20 forest patches of differing size and connectivity in southern Quebec (Canada). Within each patch, herbivory was quantified at the interior, edge, and canopy of sugar maple trees during the spring and summer of 2011 and 2012. Results show that connectivity affects herbivory differently depending on the location within the patch (edge, interior, canopy), an effect that would have gone unnoticed if samples were pooled across locations. These results suggest considering structure at both the patch and within patch scales may help to elucidate patterns when studying the effects of fragmentation on ecosystem processes, with implications for the services they support.

  5. Landscape genetics indicate recently increased habitat fragmentation in African forest-associated chafers.

    PubMed

    Eberle, Jonas; Rödder, Dennis; Beckett, Marc; Ahrens, Dirk

    2017-01-07

    Today, indigenous forests cover less than 0.6% of South Africa's land surface and are highly fragmented. Most forest relicts are very small and typically occur in fire-protected gorges along the eastern Great Escarpment. Yet, they hold a unique and valuable fauna with high endemism and ancient phylogenetic lineages, fostered by long-term climatic stability and complex microclimates. Despite numerous studies on southern African vegetation cover, the current state of knowledge about the natural extension of indigenous forests is rather fragmentary. We use an integrated approach of population-level phylogeography and climatic niche modeling of forest-associated chafer species to assess connectivity and extent of forest habitats since the last glacial maximum. Current and past species distribution models ascertained potential fluctuations of forest distribution and supported a much wider potential current extension of forests based on climatic data. Considerable genetic admixture of mitochondrial and nuclear DNA among many populations and an increase in mean population mutation rate in Extended Bayesian Skyline Plots of all species indicated more extended or better connected forests in the recent past (<5 kya). Genetic isolation of certain populations, as revealed by population differentiation statistics (GST'), as well as landscape connectivity statistics and habitat succession scenarios suggests considerable loss of habitat connectivity. As major anthropogenic influence is likely, conservational actions need to be considered.

  6. Response of the agile antechinus to habitat edge, configuration and condition in fragmented forest.

    PubMed

    Johnstone, Christopher P; Lill, Alan; Reina, Richard D

    2011-01-01

    Habitat fragmentation and degradation seriously threaten native animal communities. We studied the response of a small marsupial, the agile antechinus Antechinus agilis, to several environmental variables in anthropogenically fragmented Eucalyptus forest in south-east Australia. Agile antechinus were captured more in microhabitats dominated by woody debris than in other microhabitats. Relative abundances of both sexes were positively correlated with fragment core area. Male and female mass-size residuals were smaller in larger fragments. A health status indicator, haemoglobin-haematocrit residuals (HHR), did not vary as a function of any environmental variable in females, but male HHR indicated better health where sites' microhabitats were dominated by shrubs, woody debris and trees other than Eucalyptus. Females were trapped less often in edge than interior fragment habitat and their physiological stress level, indicated by the neutrophil/lymphocyte ratio in peripheral blood, was higher where fragments had a greater proportion of edge habitat. The latter trend was potentially due to lymphopoenia resulting from stress hormone-mediated leukocyte trafficking. Using multiple indicators of population condition and health status facilitates a comprehensive examination of the effects of anthropogenic disturbances, such as habitat fragmentation and degradation, on native vertebrates. Male agile antechinus' health responded negatively to habitat degradation, whilst females responded negatively to the proportion of edge habitat. The health and condition indicators used could be employed to identify conservation strategies that would make habitat fragments less stressful for this or similar native, small mammals.

  7. Tropical Forest Fragmentation Affects Floral Visitors but Not the Structure of Individual-Based Palm-Pollinator Networks

    PubMed Central

    Dáttilo, Wesley; Aguirre, Armando; Quesada, Mauricio; Dirzo, Rodolfo

    2015-01-01

    Despite increasing knowledge about the effects of habitat loss on pollinators in natural landscapes, information is very limited regarding the underlying mechanisms of forest fragmentation affecting plant-pollinator interactions in such landscapes. Here, we used a network approach to describe the effects of forest fragmentation on the patterns of interactions involving the understory dominant palm Astrocaryum mexicanum (Arecaceae) and its floral visitors (including both effective and non-effective pollinators) at the individual level in a Mexican tropical rainforest landscape. Specifically, we asked: (i) Does fragment size affect the structure of individual-based plant-pollinator networks? (ii) Does the core of highly interacting visitor species change along the fragmentation size gradient? (iii) Does forest fragment size influence the abundance of effective pollinators of A. mexicanum? We found that fragment size did not affect the topological structure of the individual-based palm-pollinator network. Furthermore, while the composition of peripheral non-effective pollinators changed depending on fragment size, effective core generalist species of pollinators remained stable. We also observed that both abundance and variance of effective pollinators of male and female flowers of A. mexicanum increased with forest fragment size. These findings indicate that the presence of effective pollinators in the core of all forest fragments could keep the network structure stable along the gradient of forest fragmentation. In addition, pollination of A. mexicanum could be more effective in larger fragments, since the greater abundance of pollinators in these fragments may increase the amount of pollen and diversity of pollen donors between flowers of individual plants. Given the prevalence of fragmentation in tropical ecosystems, our results indicate that the current patterns of land use will have consequences on the underlying mechanisms of pollination in remnant forests

  8. Tropical forest fragmentation affects floral visitors but not the structure of individual-based palm-pollinator networks.

    PubMed

    Dáttilo, Wesley; Aguirre, Armando; Quesada, Mauricio; Dirzo, Rodolfo

    2015-01-01

    Despite increasing knowledge about the effects of habitat loss on pollinators in natural landscapes, information is very limited regarding the underlying mechanisms of forest fragmentation affecting plant-pollinator interactions in such landscapes. Here, we used a network approach to describe the effects of forest fragmentation on the patterns of interactions involving the understory dominant palm Astrocaryum mexicanum (Arecaceae) and its floral visitors (including both effective and non-effective pollinators) at the individual level in a Mexican tropical rainforest landscape. Specifically, we asked: (i) Does fragment size affect the structure of individual-based plant-pollinator networks? (ii) Does the core of highly interacting visitor species change along the fragmentation size gradient? (iii) Does forest fragment size influence the abundance of effective pollinators of A. mexicanum? We found that fragment size did not affect the topological structure of the individual-based palm-pollinator network. Furthermore, while the composition of peripheral non-effective pollinators changed depending on fragment size, effective core generalist species of pollinators remained stable. We also observed that both abundance and variance of effective pollinators of male and female flowers of A. mexicanum increased with forest fragment size. These findings indicate that the presence of effective pollinators in the core of all forest fragments could keep the network structure stable along the gradient of forest fragmentation. In addition, pollination of A. mexicanum could be more effective in larger fragments, since the greater abundance of pollinators in these fragments may increase the amount of pollen and diversity of pollen donors between flowers of individual plants. Given the prevalence of fragmentation in tropical ecosystems, our results indicate that the current patterns of land use will have consequences on the underlying mechanisms of pollination in remnant forests.

  9. Ecology of maritime forests of the southern Atlantic coast: A community profile

    SciTech Connect

    Bellis, V.J.

    1995-05-01

    Maritime forests dominated by broadleaved evergreen trees and shrubs occur in a discontinuous narrow band along the barrier islands and on the adjacent mainland from North Carolina to Florida. The flora and fauna of maritime forests typically consist of a distinctive subset of the regional biota that is particularly well adapted to survive the elevated salt content, limited availability of fresh water, soil erosion and dune migration, periodic seawater inundation, and wind damage associated with oceanic storms. Recent recognition of the relatively greater physical stability of maritime forests compared to the beachfront has resulted in intensified urban development within them. Maritime forests across the range have been increasingly impaired by clearing for roads and parking lots and fragmented by subdivision development.

  10. Robustness of plant-insect herbivore interaction networks to climate change in a fragmented temperate forest landscape.

    PubMed

    Bähner, K W; Zweig, K A; Leal, I R; Wirth, R

    2017-02-10

    Forest fragmentation and climate change are among the most severe and pervasive forms of human impact. Yet, their combined effects on plant-insect herbivore interaction networks, essential components of forest ecosystems with respect to biodiversity and functioning, are still poorly investigated, particularly in temperate forests. We addressed this issue by analysing plant-insect herbivore networks (PIHNs) from understories of three managed beech forest habitats: small forest fragments (2.2-145 ha), forest edges and forest interior areas within three continuous control forests (1050-5600 ha) in an old hyper-fragmented forest landscape in SW Germany. We assessed the impact of forest fragmentation, particularly edge effects, on PIHNs and the resulting differences in robustness against climate change by habitat-wise comparison of network topology and biologically realistic extinction cascades of networks following scores of vulnerability to climate change for the food plant species involved. Both the topological network metrics (complexity, nestedness, trophic niche redundancy) and robustness to climate change strongly increased in forest edges and fragments as opposed to the managed forest interior. The nature of the changes indicates that human impacts modify network structure mainly via host plant availability to insect herbivores. Improved robustness of PIHNs in forest edges/small fragments to climate-driven extinction cascades was attributable to an overall higher thermotolerance across plant communities, along with positive effects of network structure. The impoverishment of PIHNs in managed forest interiors and the suggested loss of insect diversity from climate-induced co-extinction highlight the need for further research efforts focusing on adequate silvicultural and conservation approaches.

  11. Conservation value of a native forest fragment in a region of extensive agriculture.

    PubMed

    Chiarello

    2000-05-01

    A survey of mammals and birds was carried out in a semi-deciduous forest fragment of 150 ha located in a zone of intensive agriculture in Ribeirão Preto, State of São Paulo, south-eastern Brazil. Line transect sampling was used to census mammals and birds during six days, totalling 27.8 km of trails and 27.8 hours of observation. Twenty mammal species were confirmed in the area (except bats and small mammals), including rare or endangered species, such as the mountain lion (Puma concolor), the maned wolf (Chrysocyon brachyurus), and the ocelot (Leopardus pardalis). The brown capuchin monkey (Cebus apella) and the black-tufted-ear marmoset (Callithrix penicillata) were found frequently, suggesting high population density in the fragment. Regarding the avifauna, 49 bird species were recorded, most of them typical of open areas or forest edges. Some confirmed species, however, are becoming increasingly rare in the region, as for example the muscovy duck (Cairina moschata) and the toco toucan (Ramphastos toco). The results demonstrate that forest fragment of this size are refuges for native fauna in a region dominated almost exclusively by sugar-cane plantations. Besides faunal aspects, the conservation of these fragments is of great importance for the establishment of studies related to species preservation in the long term, including reintroduction and translocation projects, as well as studies related to genetic health of isolated populations.

  12. Effects of local tree diversity on herbivore communities diminish with increasing forest fragmentation on the landscape scale.

    PubMed

    Peter, Franziska; Berens, Dana G; Farwig, Nina

    2014-01-01

    Forest fragmentation and plant diversity have been shown to play a crucial role for herbivorous insects (herbivores, hereafter). In turn, herbivory-induced leaf area loss is known to have direct implications for plant growth and reproduction as well as long-term consequences for ecosystem functioning and forest regeneration. So far, previous studies determined diverging responses of herbivores to forest fragmentation and plant diversity. Those inconsistent results may be owed to complex interactive effects of both co-occurring environmental factors albeit they act on different spatial scales. In this study, we investigated whether forest fragmentation on the landscape scale and tree diversity on the local habitat scale show interactive effects on the herbivore community and leaf area loss in subtropical forests in South Africa. We applied standardized beating samples and a community-based approach to estimate changes in herbivore community composition, herbivore abundance, and the effective number of herbivore species on the tree species-level. We further monitored leaf area loss to link changes in the herbivore community to the associated process of herbivory. Forest fragmentation and tree diversity interactively affected the herbivore community composition, mainly by a species turnover within the family of Curculionidae. Furthermore, herbivore abundance increased and the number of herbivore species decreased with increasing tree diversity in slightly fragmented forests whereas the effects diminished with increasing forest fragmentation. Surprisingly, leaf area loss was neither affected by forest fragmentation or tree diversity, nor by changes in the herbivore community. Our study highlights the need to consider interactive effects of environmental changes across spatial scales in order to draw reliable conclusions for community and interaction patterns. Moreover, forest fragmentation seems to alter the effect of tree diversity on the herbivore community, and thus

  13. Multitemporal analysis of forest fragmentation in Hindu Kush Himalaya-a case study from Khangchendzonga Biosphere Reserve, Sikkim, India.

    PubMed

    Sharma, Mohit; Areendran, G; Raj, Krishna; Sharma, Ankita; Joshi, P K

    2016-10-01

    Forests in the mountains are a treasure trove; harbour a large biodiversity; and provide fodder, firewood, timber and non-timber forest products; all of these are essential for human survival in the highest mountains on earth. The present paper attempts a spatiotemporal assessment of forest fragmentation and changes in land use land cover (LULC) pattern using multitemporal satellite data over a time span of around a decade (2000-2009), within the third highest protected area (PA) in the world. The fragmentation analysis using Landscape Fragmentation Tool (LFT) depicts a decrease in large core, edge and patches areas by 5.93, 3.64 and 0.66 %, respectively, while an increase in non-forest and perforated areas by 6.59 and 4.01 %, respectively. The land cover dynamics shows a decrease in open forest, alpine scrub, alpine meadows, snow and hill shadow areas by 2.81, 0.39, 8.18, 3.46 and 0.60 %, respectively, and there is an increase in dense forest and glacier area by 4.79 and 10.65 %, respectively. The change analysis shows a major transformation in areas from open forest to dense forest and from alpine meadows to alpine scrub. In order to quantify changes induced by forest fragmentation and to characterize composition and configuration of LULC mosaics, fragmentation indices were computed using Fragstats at class level, showing the signs of accelerated fragmentation. The outcome of the analysis revealed the effectiveness of geospatial tools coupled with landscape ecology in characterization and quantification of forest fragmentation and land cover changes. The present study provides a baseline database for sustainable conservation planning that will benefit the subsistence livelihoods in the region. Recommendations made based on the present analysis will help to recover forest and halt the pessimistic effects of fragmentation and land cover changes on biodiversity and ecosystem services in the region.

  14. Patch Size and Isolation Predict Plant Species Density in a Naturally Fragmented Forest

    PubMed Central

    Munguía-Rosas, Miguel A.; Montiel, Salvador

    2014-01-01

    Studies of the effects of patch size and isolation on plant species density have yielded contrasting results. However, much of the available evidence comes from relatively recent anthropogenic forest fragments which have not reached equilibrium between extinction and immigration. This is a critical issue because the theory clearly states that only when equilibrium has been reached can the number of species be accurately predicted by habitat size and isolation. Therefore, species density could be better predicted by patch size and isolation in an ecosystem that has been fragmented for a very long time. We tested whether patch area, isolation and other spatial variables explain variation among forest patches in plant species density in an ecosystem where the forest has been naturally fragmented for long periods of time on a geological scale. Our main predictions were that plant species density will be positively correlated with patch size, and negatively correlated with isolation (distance to the nearest patch, connectivity, and distance to the continuous forest). We surveyed the vascular flora (except lianas and epiphytes) of 19 forest patches using five belt transects (50×4 m each) per patch (area sampled per patch = 0.1 ha). As predicted, plant species density was positively associated (logarithmically) with patch size and negatively associated (linearly) with patch isolation (distance to the nearest patch). Other spatial variables such as patch elevation and perimeter, did not explain among-patch variability in plant species density. The power of patch area and isolation as predictors of plant species density was moderate (together they explain 43% of the variation), however, a larger sample size may improve the explanatory power of these variables. Patch size and isolation may be suitable predictors of long-term plant species density in terrestrial ecosystems that are naturally and anthropogenically fragmented. PMID:25347818

  15. Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

    USGS Publications Warehouse

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.

  16. Surveys of Puerto Rican screech-owl populations in large-tract and fragmented forest habitats

    USGS Publications Warehouse

    Pardieck, K.L.; Meyers, J.M.; Pagan, M.

    1996-01-01

    We conducted road surveys of Puerto Rican Screech-Owls (Otus nudipes) by playing conspecific vocalizations in secondary wet forest and fragmented secondary moist forest in rural areas of eastern Puerto Rico. Six paired surveys were conducted bi-weekly beginning in April. We recorded number of owl responses, cloud cover, wind speed, moon phase, and number of passing cars during 5-min stops at 60 locations. Owls responded in similar numbers (P > 0.05) in both habitat types. Also, we detected no association with cloud cover, wind speed, moon phase, or passing cars.

  17. Spatial dynamics of deforestation and forest fragmentation (1930-2013) in Eastern Ghats, India

    NASA Astrophysics Data System (ADS)

    Sudhakar Reddy, C.; Jha, C. S.; Dadhwal, V. K.

    2014-11-01

    The tropical forests are the most unique ecosystems for their potential economic value. Eastern Ghats, a phytogeographical region of India has rugged hilly terrain distributed in parts of five states, viz. Odisha, Andhra Pradesh, Telangana, Karnataka and Tamil Nadu. The present study is mainly aimed to analyse the trends in deforestation and its role in forest fragmentation of Eastern Ghats. The long term changes in forest cover with its spatial pattern over time has been assessed by analyzing a set of topographical maps and satellite remote sensing datasets. The multi-source and multi-date mapping has been carried out using survey of India topographical maps (1930's), Landsat MSS (1975 and 1985), IRS 1B LISS-I (1995), IRS P6 AWiFS (2005) and Resourcesat-2 AWiFS (2013) satellite images. The classified spatial data for 1930, 1975, 1985, 1995, 2005 and 2013 showed that the forest cover for the mentioned years are 102213 km2 (45.6 %), 76630 (34.2 %), 73416 km2 (32.7 %), 71730 km2 (32 %), 71305 km2 (31.8 %) and 71186 km2 (31.7 %) of the geographical area of Eastern Ghats respectively. A spatial statistical analysis of the deforestation rates and forest cover change were carried out based on distinctive time phases, i.e. 1930-1975, 1975-1985, 1985-1995, 1995-2005 and 2005-2013. The spatial analysis was carried out first by segmenting the study area into grid cells of 5 km x 5 km for time series assessment and determining spatial changes in forests. The distribution of loss and gain of forest was calculated across six classes i.e. <1 km2, 1-5 km2, 5-10 km2, 10-15 km2, 15-20 km2 and >20 km2. Landscape metrics were used to quantify spatial variability of landscape structure and composition. The results of study on net rate of deforestation was found to be 0.64 during 1935 to 1975, 0.43 during 1975-1985, 0.23 during 1985-1995, 0.06 during 1995-2005 and 0.02 during 2005-2013. The number of forest patches increased from 2688 (1930) to 13009 (2013). The largest forest patch in

  18. Gene Flow of a Forest-Dependent Bird across a Fragmented Landscape.

    PubMed

    Adams, Rachael V; Burg, Theresa M

    2015-01-01

    Habitat loss and fragmentation can affect the persistence of populations by reducing connectivity and restricting the ability of individuals to disperse across landscapes. Dispersal corridors promote population connectivity and therefore play important roles in maintaining gene flow in natural populations inhabiting fragmented landscapes. In the prairies, forests are restricted to riparian areas along river systems which act as important dispersal corridors for forest dependent species across large expanses of unsuitable grassland habitat. However, natural and anthropogenic barriers within riparian systems have fragmented these forested habitats. In this study, we used microsatellite markers to assess the fine-scale genetic structure of a forest-dependent species, the black-capped chickadee (Poecile atricapillus), along 10 different river systems in Southern Alberta. Using a landscape genetic approach, landscape features (e.g., land cover) were found to have a significant effect on patterns of genetic differentiation. Populations are genetically structured as a result of natural breaks in continuous habitat at small spatial scales, but the artificial barriers we tested do not appear to restrict gene flow. Dispersal between rivers is impeded by grasslands, evident from isolation of nearby populations (~ 50 km apart), but also within river systems by large treeless canyons (>100 km). Significant population genetic differentiation within some rivers corresponded with zones of different cottonwood (riparian poplar) tree species and their hybrids. This study illustrates the importance of considering the impacts of habitat fragmentation at small spatial scales as well as other ecological processes to gain a better understanding of how organisms respond to their environmental connectivity. Here, even in a common and widespread songbird with high dispersal potential, small breaks in continuous habitats strongly influenced the spatial patterns of genetic variation.

  19. Gene Flow of a Forest-Dependent Bird across a Fragmented Landscape

    PubMed Central

    2015-01-01

    Habitat loss and fragmentation can affect the persistence of populations by reducing connectivity and restricting the ability of individuals to disperse across landscapes. Dispersal corridors promote population connectivity and therefore play important roles in maintaining gene flow in natural populations inhabiting fragmented landscapes. In the prairies, forests are restricted to riparian areas along river systems which act as important dispersal corridors for forest dependent species across large expanses of unsuitable grassland habitat. However, natural and anthropogenic barriers within riparian systems have fragmented these forested habitats. In this study, we used microsatellite markers to assess the fine-scale genetic structure of a forest-dependent species, the black-capped chickadee (Poecile atricapillus), along 10 different river systems in Southern Alberta. Using a landscape genetic approach, landscape features (e.g., land cover) were found to have a significant effect on patterns of genetic differentiation. Populations are genetically structured as a result of natural breaks in continuous habitat at small spatial scales, but the artificial barriers we tested do not appear to restrict gene flow. Dispersal between rivers is impeded by grasslands, evident from isolation of nearby populations (~ 50 km apart), but also within river systems by large treeless canyons (>100 km). Significant population genetic differentiation within some rivers corresponded with zones of different cottonwood (riparian poplar) tree species and their hybrids. This study illustrates the importance of considering the impacts of habitat fragmentation at small spatial scales as well as other ecological processes to gain a better understanding of how organisms respond to their environmental connectivity. Here, even in a common and widespread songbird with high dispersal potential, small breaks in continuous habitats strongly influenced the spatial patterns of genetic variation. PMID

  20. Intraspecific variations in dispersal ability of saproxylic beetles in fragmented forest patches.

    PubMed

    Bouget, C; Brin, A; Tellez, D; Archaux, F

    2015-03-01

    The extrapolation of metapopulation concepts to saproxylic insects suggests that the occupancy of forest patches and the colonization of ephemeral deadwood substrates are driven by micro-evolutionary processes that are related to adaptive plasticity and intraspecific sex-dependent polymorphism of dispersal traits. We hypothesized that forest fragmentation could favor more mobile individuals within populations, but little empirical data have been published on the potentially sex-biased response of insect populations to habitat availability. We selected 88 fragmented woodlots in two European agricultural landscapes to cover different degrees of spatio-temporal fragmentation, from small, isolated and recently established woodlots to large, inter-connected ancient woodlots. In line with our hypothesis, the average wing loading (WL), used as a proxy for dispersal ability, for each of nine flight-dispersing saproxylic beetle species should be lower in recent, small, isolated woodlots than in ancient, large, inter-connected woodlots, respectively (i.e. ancient vs. recent, small vs. large, isolated vs. connected). Forest patch size did not significantly influence the average dispersal ability of beetle colonizers. However, WL of one-third of the tested species did significantly respond to forest ancientness or connectivity. Significant patterns were sex-biased, probably due to the contrasting role of males and females in species colonization dynamics. WL was lower in recent than in ancient forest plots for Melandrya barbata males, and it was lower in isolated than in connected woodlots for Tetratoma ancora and Phymatodes testaceus males. Contrary to expectations, we did not observe any decrease in polymorphism of dispersal abilities with decreasing woodlot size or increasing isolation. Our findings give support to the usefulness of gender consideration in insect conservation ecology studies.

  1. Determining coniferous forest cover and forest fragmentation with NOAA-9 advanced very high resolution radiometer data

    NASA Technical Reports Server (NTRS)

    Ripple, William J.

    1995-01-01

    NOAA-9 satellite data from the Advanced Very High Resolution Radiometer (AVHRR) were used in conjunction with Landsat Multispectral Scanner (MSS) data to determine the proportion of closed canopy conifer forest cover in the Cascade Range of Oregon. A closed canopy conifer map, as determined from the MSS, was registered with AVHRR pixels. Regression was used to relate closed canopy conifer forest cover to AVHRR spectral data. A two-variable (band) regression model accounted for more variance in conifer cover than the Normalized Difference Vegetation Index (NDVI). The spectral signatures of various conifer successional stages were also examined. A map of Oregon was produced showing the proportion of closed canopy conifer cover for each AVHRR pixel. The AVHRR was responsive to both the percentage of closed canopy conifer cover and the successional stage in these temperate coniferous forests in this experiment.

  2. Extinction debt of forest plants persists for more than a century following habitat fragmentation.

    PubMed

    Vellend, Mark; Verheyen, Kris; Jacquemyn, Hans; Kolb, Annette; Van Calster, Hans; Peterken, George; Hermy, Martin

    2006-03-01

    Following habitat fragmentation individual habitat patches may lose species over time as they pay off their "extinction debt." Species with relatively low rates of population extinction and colonization ("slow" species) may maintain extinction debts for particularly prolonged periods, but few data are available to test this prediction. We analyzed two unusually detailed data sets on forest plant distributions and land-use history from Lincolnshire, United Kingdom, and Vlaams-Brabant, Belgium, to test for an extinction debt in relation to species-specific extinction and colonization rates. Logistic regression models predicting the presence-absence of 36 plant species were first parameterized using data from Lincolnshire, where forest cover has been relatively low (approximately 5-8%) for the past 1000 years. Consistent with extinction debt theory, for relatively slow species (but not fast species) these models systematically underpredicted levels of patch occupancy in Vlaams-Brabant, where forest cover was reduced from approximately 25% to <10% between 1775 and 1900 (it is presently 6.5%). As a consequence, the ability of the Lincolnshire models to predict patch occupancy in Vlaams-Brabant was worse for slow than for fast species. Thus, more than a century after forest fragmentation reached its current level an extinction debt persists for species with low rates of population turnover.

  3. Frugivorous Bats Maintain Functional Habitat Connectivity in Agricultural Landscapes but Rely Strongly on Natural Forest Fragments

    PubMed Central

    Ripperger, Simon P.; Kalko, Elisabeth K. V.; Rodríguez-Herrera, Bernal; Mayer, Frieder; Tschapka, Marco

    2015-01-01

    Anthropogenic changes in land use threaten biodiversity and ecosystem functioning by the conversion of natural habitat into agricultural mosaic landscapes, often with drastic consequences for the associated fauna. The first step in the development of efficient conservation plans is to understand movement of animals through complex habitat mosaics. Therefore, we studied ranging behavior and habitat use in Dermanura watsoni (Phyllostomidae), a frugivorous bat species that is a valuable seed disperser in degraded ecosystems. Radio-tracking of sixteen bats showed that the animals strongly rely on natural forest. Day roosts were exclusively located within mature forest fragments. Selection ratios showed that the bats foraged selectively within the available habitat and positively selected natural forest. However, larger daily ranges were associated with higher use of degraded habitats. Home range geometry and composition of focal foraging areas indicated that wider ranging bats performed directional foraging bouts from natural to degraded forest sites traversing the matrix over distances of up to three hundred meters. This behavior demonstrates the potential of frugivorous bats to functionally connect fragmented areas by providing ecosystem services between natural and degraded sites, and highlights the need for conservation of natural habitat patches within agricultural landscapes that meet the roosting requirements of bats. PMID:25830222

  4. Frugivorous bats maintain functional habitat connectivity in agricultural landscapes but rely strongly on natural forest fragments.

    PubMed

    Ripperger, Simon P; Kalko, Elisabeth K V; Rodríguez-Herrera, Bernal; Mayer, Frieder; Tschapka, Marco

    2015-01-01

    Anthropogenic changes in land use threaten biodiversity and ecosystem functioning by the conversion of natural habitat into agricultural mosaic landscapes, often with drastic consequences for the associated fauna. The first step in the development of efficient conservation plans is to understand movement of animals through complex habitat mosaics. Therefore, we studied ranging behavior and habitat use in Dermanura watsoni (Phyllostomidae), a frugivorous bat species that is a valuable seed disperser in degraded ecosystems. Radio-tracking of sixteen bats showed that the animals strongly rely on natural forest. Day roosts were exclusively located within mature forest fragments. Selection ratios showed that the bats foraged selectively within the available habitat and positively selected natural forest. However, larger daily ranges were associated with higher use of degraded habitats. Home range geometry and composition of focal foraging areas indicated that wider ranging bats performed directional foraging bouts from natural to degraded forest sites traversing the matrix over distances of up to three hundred meters. This behavior demonstrates the potential of frugivorous bats to functionally connect fragmented areas by providing ecosystem services between natural and degraded sites, and highlights the need for conservation of natural habitat patches within agricultural landscapes that meet the roosting requirements of bats.

  5. Got Dung? Resource Selection by Dung Beetles in Neotropical Forest Fragments and Cattle Pastures.

    PubMed

    Bourg, A; Escobar, F; MacGregor-Fors, I; Moreno, C E

    2016-10-01

    Both the impact of habitat modification on the food preferences of species and its impact on ecosystem functioning are poorly understood. In this study, we analyzed food selection by dung beetles in 80 tropical forest fragments and their adjacent cattle pastures in the Los Tuxtlas Biosphere Reserve, Mexico. Ten pitfall traps were placed at each site, half baited with human dung and the other half with fish carrion. We assessed dung beetle food selection and classified any specialization in resource use quantitatively using a multinomial classification model. We collected 15,445 beetles belonging to 42 species, 8747 beetles (38 species) in forest fragments and 6698 beetles (29 species) in cattle pastures. Twenty-five species were present in both habitats. Of all the beetles captured, 76% were caught in dung traps (11,727 individuals) and 24% in carrion traps (3718 individuals). We found 21 species of dung specialists, 7 carrion specialists, 8 generalists, and 6 species too rare to classify. The bait most frequently selected by beetles in this study was dung in both forests and pastures. Specialists tended to remain specialists in both habitats, while generalists tended to change their selection of bait type depending on the habitat. In summary, our results show that replacing forests with cattle pastures modifies the patterns of resource selection by dung beetles and this could affect ecosystem functioning.

  6. Time-Lag in Responses of Birds to Atlantic Forest Fragmentation: Restoration Opportunity and Urgency

    PubMed Central

    Uezu, Alexandre; Metzger, Jean Paul

    2016-01-01

    There are few opportunities to evaluate the relative importance of landscape structure and dynamics upon biodiversity, especially in highly fragmented tropical landscapes. Conservation strategies and species risk evaluations often rely exclusively on current aspects of landscape structure, although such limited assumptions are known to be misleading when time-lag responses occur. By relating bird functional-group richness to forest patch size and isolation in ten-year intervals (1956, 1965, 1978, 1984, 1993 and 2003), we revealed that birds with different sensitivity to fragmentation display contrasting responses to landscape dynamics in the Brazilian Atlantic Forest. For non-sensitive groups, there was no time-lag in response: the recent degree of isolation best explains their variation in richness, which likely relates to these species’ flexibility to adapt to changes in landscape structure. However, for sensitive bird groups, the 1978 patch area was the best explanatory variable, providing evidence for a 25-year time-lag in response to habitat reduction. Time-lag was more likely in landscapes that encompass large patches, which can support temporarily the presence of some sensitive species, even when habitat cover is relatively low. These landscapes potentially support the most threatened populations and should be priorities for restoration efforts to avoid further species loss. Although time-lags provide an opportunity to counteract the negative consequences of fragmentation, it also reinforces the urgency of restoration actions. Fragmented landscapes will be depleted of biodiversity if landscape structure is only maintained, and not improved. The urgency of restoration action may be even higher in landscapes where habitat loss and fragmentation history is older and where no large fragment remained to act temporarily as a refuge. PMID:26820548

  7. Time-Lag in Responses of Birds to Atlantic Forest Fragmentation: Restoration Opportunity and Urgency.

    PubMed

    Uezu, Alexandre; Metzger, Jean Paul

    2016-01-01

    There are few opportunities to evaluate the relative importance of landscape structure and dynamics upon biodiversity, especially in highly fragmented tropical landscapes. Conservation strategies and species risk evaluations often rely exclusively on current aspects of landscape structure, although such limited assumptions are known to be misleading when time-lag responses occur. By relating bird functional-group richness to forest patch size and isolation in ten-year intervals (1956, 1965, 1978, 1984, 1993 and 2003), we revealed that birds with different sensitivity to fragmentation display contrasting responses to landscape dynamics in the Brazilian Atlantic Forest. For non-sensitive groups, there was no time-lag in response: the recent degree of isolation best explains their variation in richness, which likely relates to these species' flexibility to adapt to changes in landscape structure. However, for sensitive bird groups, the 1978 patch area was the best explanatory variable, providing evidence for a 25-year time-lag in response to habitat reduction. Time-lag was more likely in landscapes that encompass large patches, which can support temporarily the presence of some sensitive species, even when habitat cover is relatively low. These landscapes potentially support the most threatened populations and should be priorities for restoration efforts to avoid further species loss. Although time-lags provide an opportunity to counteract the negative consequences of fragmentation, it also reinforces the urgency of restoration actions. Fragmented landscapes will be depleted of biodiversity if landscape structure is only maintained, and not improved. The urgency of restoration action may be even higher in landscapes where habitat loss and fragmentation history is older and where no large fragment remained to act temporarily as a refuge.

  8. Fragmentation and Management of Ethiopian Moist Evergreen Forest Drive Compositional Shifts of Insect Communities Visiting Wild Arabica Coffee Flowers

    NASA Astrophysics Data System (ADS)

    Berecha, Gezahegn; Aerts, Raf; Muys, Bart; Honnay, Olivier

    2015-02-01

    Coffea arabica is an indigenous understorey shrub of the moist evergreen Afromontane forest of SW Ethiopia. Coffee cultivation here occurs under different forest management intensities, ranging from almost no intervention in the `forest coffee' system to far-reaching interventions that include the removal of competing shrubs and selective thinning of the upper canopy in the `semi-forest coffee' system. We investigated whether increasing forest management intensity and fragmentation result in impacts upon potential coffee pollination services through examining shifts in insect communities that visit coffee flowers. Overall, we netted 2,976 insect individuals on C. arabica flowers, belonging to sixteen taxonomic groups, comprising 10 insect orders. Taxonomic richness of the flower-visiting insects significantly decreased and pollinator community changed with increasing forest management intensity and fragmentation. The relative abundance of honey bees significantly increased with increasing forest management intensity and fragmentation, likely resulting from the introduction of bee hives in the most intensively managed forests. The impoverishment of the insect communities through increased forest management intensity and fragmentation potentially decreases the resilience of the coffee production system as pollination increasingly relies on honey bees alone. This may negatively affect coffee productivity in the long term as global pollination services by managed honey bees are expected to decline under current climate change scenarios. Coffee agroforestry management practices should urgently integrate pollinator conservation measures.

  9. Fragmentation and management of Ethiopian moist evergreen forest drive compositional shifts of insect communities visiting wild Arabica coffee flowers.

    PubMed

    Berecha, Gezahegn; Aerts, Raf; Muys, Bart; Honnay, Olivier

    2015-02-01

    Coffea arabica is an indigenous understorey shrub of the moist evergreen Afromontane forest of SW Ethiopia. Coffee cultivation here occurs under different forest management intensities, ranging from almost no intervention in the 'forest coffee' system to far-reaching interventions that include the removal of competing shrubs and selective thinning of the upper canopy in the 'semi-forest coffee' system. We investigated whether increasing forest management intensity and fragmentation result in impacts upon potential coffee pollination services through examining shifts in insect communities that visit coffee flowers. Overall, we netted 2,976 insect individuals on C. arabica flowers, belonging to sixteen taxonomic groups, comprising 10 insect orders. Taxonomic richness of the flower-visiting insects significantly decreased and pollinator community changed with increasing forest management intensity and fragmentation. The relative abundance of honey bees significantly increased with increasing forest management intensity and fragmentation, likely resulting from the introduction of bee hives in the most intensively managed forests. The impoverishment of the insect communities through increased forest management intensity and fragmentation potentially decreases the resilience of the coffee production system as pollination increasingly relies on honey bees alone. This may negatively affect coffee productivity in the long term as global pollination services by managed honey bees are expected to decline under current climate change scenarios. Coffee agroforestry management practices should urgently integrate pollinator conservation measures.

  10. [Response of the ant community to attributes of fragments and vegetation in a northeastern Atlantic Rain Forest area, Brazil].

    PubMed

    Gomes, Juliana P; Iannuzzi, Luciana; Leal, Inara R

    2010-01-01

    The objective of this study was to determine the effects of forest fragmentation on ant richness in a landscape of Atlantic Forest in Northeast Brazil. More specifically, the ant richness was related to the attributes of fragments (area and distance from the fragment central point to the edge), landscape (forest cover surrounding the fragments), and tree community (plant density, richness, and percentage of shade tolerant species). The surveys were carried out in 19 fragments located in Alagoas State from October 2007 to March 2008. Samples were collected through a 300 m transect established in the center of each fragment, where 30 1-m² leaf litter samples were collected at 10 m intervals. A total of 146 ant species was collected, which belonged to 42 genera, 24 tribes and nine subfamilies. The attributes of fragments and landscape did not influence ant richness. On the other hand, tree density explained ca. 23% of ant richness. In relation to functional groups, both density and richness of trees explained the richness of general myrmicines (the whole model explained ca. 42% of the variation in this group) and percentage of shade tolerant trees explained the richness of specialist predator ants (30% for the whole model). These results indicate that ant fauna is more influenced by vegetation integrity than by fragment size, distance to edge or forest cover surrounding fragments.

  11. Sleeping Sites and Latrines of Spider Monkeys in Continuous and Fragmented Rainforests: Implications for Seed Dispersal and Forest Regeneration

    PubMed Central

    González-Zamora, Arturo; Arroyo-Rodríguez, Víctor; Oyama, Ken; Sork, Victoria; Chapman, Colin A.; Stoner, Kathryn E.

    2012-01-01

    Spider monkeys (Ateles geoffroyi) use sites composed of one or more trees for sleeping (sleeping sites and sleeping trees, respectively). Beneath these sites/trees they deposit copious amounts of dung in latrines. This behavior results in a clumped deposition pattern of seeds and nutrients that directly impacts the regeneration of tropical forests. Therefore, information on the density and spatial distribution of sleeping sites and latrines, and the characteristics (i.e., composition and structure) of sleeping trees are needed to improve our understanding of the ecological significance of spider monkeys in influencing forest composition. Moreover, since primate populations are increasingly forced to inhabit fragmented landscapes, it is important to assess if these characteristics differ between continuous and fragmented forests. We assessed this novel information from eight independent spider monkey communities in the Lacandona rainforest, Mexico: four continuous forest sites and four forest fragments. Both the density of sleeping sites and latrines did not differ between forest conditions. Latrines were uniformly distributed across sleeping sites, but the spatial distribution of sleeping sites within the areas was highly variable, being particularly clumped in forest fragments. In fact, the average inter-latrine distances were almost double in continuous forest than in fragments. Latrines were located beneath only a few tree species, and these trees were larger in diameter in continuous than fragmented forests. Because latrines may represent hotspots of seedling recruitment, our results have important ecological and conservation implications. The variation in the spatial distribution of sleeping sites across the forest indicates that spider monkeys likely create a complex seed deposition pattern in space and time. However, the use of a very few tree species for sleeping could contribute to the establishment of specific vegetation associations typical of the

  12. Sleeping sites and latrines of spider monkeys in continuous and fragmented rainforests: implications for seed dispersal and forest regeneration.

    PubMed

    González-Zamora, Arturo; Arroyo-Rodríguez, Víctor; Oyama, Ken; Sork, Victoria; Chapman, Colin A; Stoner, Kathryn E

    2012-01-01

    Spider monkeys (Ateles geoffroyi) use sites composed of one or more trees for sleeping (sleeping sites and sleeping trees, respectively). Beneath these sites/trees they deposit copious amounts of dung in latrines. This behavior results in a clumped deposition pattern of seeds and nutrients that directly impacts the regeneration of tropical forests. Therefore, information on the density and spatial distribution of sleeping sites and latrines, and the characteristics (i.e., composition and structure) of sleeping trees are needed to improve our understanding of the ecological significance of spider monkeys in influencing forest composition. Moreover, since primate populations are increasingly forced to inhabit fragmented landscapes, it is important to assess if these characteristics differ between continuous and fragmented forests. We assessed this novel information from eight independent spider monkey communities in the Lacandona rainforest, Mexico: four continuous forest sites and four forest fragments. Both the density of sleeping sites and latrines did not differ between forest conditions. Latrines were uniformly distributed across sleeping sites, but the spatial distribution of sleeping sites within the areas was highly variable, being particularly clumped in forest fragments. In fact, the average inter-latrine distances were almost double in continuous forest than in fragments. Latrines were located beneath only a few tree species, and these trees were larger in diameter in continuous than fragmented forests. Because latrines may represent hotspots of seedling recruitment, our results have important ecological and conservation implications. The variation in the spatial distribution of sleeping sites across the forest indicates that spider monkeys likely create a complex seed deposition pattern in space and time. However, the use of a very few tree species for sleeping could contribute to the establishment of specific vegetation associations typical of the

  13. Efficiency of playback for assessing the occurrence of five bird species in Brazilian Atlantic Forest fragments.

    PubMed

    Boscolo, Danilo; Metzger, Jean Paul; Vielliard, Jacques M E

    2006-12-01

    Playback of bird songs is a useful technique for species detection; however, this method is usually not standardized. We tested playback efficiency for five Atlantic Forest birds (White-browed Warbler Basileuterus leucoblepharus, Giant Antshrike Batara cinerea, Swallow-tailed Manakin Chiroxiphia caudata, Whiteshouldered Fire-eye Pyriglena leucoptera and Surucua Trogon Trogon surrucura) for different time of the day, season of the year and species abundance at the Morro Grande Forest Reserve (South-eastern Brazil) and at thirteen forest fragments in a nearby landscape. Vocalizations were broadcasted monthly at sunrise, noon and sunset, during one year. For B. leucoblepharus, C. caudata and T. surrucura, sunrise and noon were more efficient than sunset. Batara cinerea presented higher efficiency from July to October. Playback expanded the favourable period for avifaunal surveys in tropical forest, usually restricted to early morning in the breeding season. The playback was efficient in detecting the presence of all species when the abundance was not too low. But only B. leucoblepharus and T. surrucura showed abundance values significantly related to this efficiency. The present study provided a precise indication of the best daily and seasonal periods and a confidence interval to maximize the efficiency of playback to detect the occurrence of these forest species.

  14. Temporal bird community dynamics are strongly affected by landscape fragmentation in a Central American tropical forest region

    USGS Publications Warehouse

    Blandón, A.C.; Perelman, S.B.; Ramírez, M.; López, A.; Javier, O.; Robbins, Chandler S.

    2016-01-01

    Habitat loss and fragmentation are considered the main causes of species extinctions, particularly in tropical ecosystems. The objective of this work was to evaluate the temporal dynamics of tropical bird communities in landscapes with different levels of fragmentation in eastern Guatemala. We evaluated five bird community dynamic parameters for forest specialists and generalists: (1) species extinction, (2) species turnover, (3) number of colonizing species, (4) relative species richness, and (5) a homogeneity index. For each of 24 landscapes, community dynamic parameters were estimated from bird point count data, for the 1998–1999 and 2008–2009 periods, accounting for species’ detection probability. Forest specialists had higher extinction rates and a smaller number of colonizing species in landscapes with higher fragmentation, thus having lower species richness in both time periods. Alternatively, forest generalists elicited a completely different pattern, showing a curvilinear association to forest fragmentation for most parameters. Thus, greater community dynamism for forest generalists was shown in landscapes with intermediate levels of fragmentation. Our study supports general theory regarding the expected negative effects of habitat loss and fragmentation on the temporal dynamics of biotic communities, particularly for forest specialists, providing strong evidence from understudied tropical bird communities.

  15. Does avian species richness in natural patch mosaics follow the forest fragmentation paradigm?

    USGS Publications Warehouse

    Pavlacky, D.C.; Anderson, S.H.

    2007-01-01

    As one approaches the north-eastern limit of pinyon (Pinus spp.) juniper (Juniperus spp.) vegetation on the Colorado Plateau, USA, woodland patches become increasingly disjunct, grading into sagebrush (Artemisia spp.)-dominated landscapes. Patterns of avian species richness in naturally heterogeneous forests may or may not respond to patch discontinuity in the same manner as bird assemblages in fragmented agricultural systems. We used observational data from naturally patchy woodlands and predictions derived from studies of human-modified agricultural forests to estimate the effects of patch area, shape, isolation and distance to contiguous woodland on avian species richness. We predicted that patterns of species richness in naturally patchy juniper woodlands would differ from those observed in fragmented agricultural systems. Our objectives were to (1) estimate the effect of naturally occurring patch structure on avian species richness with respect to habitat affinity and migratory strategy and (2) assess the concordance of the effects to predictions from agricultural forest systems. We used the analogy between populations and communities to estimate species richness, where species are treated as individuals in the application of traditional capture-recapture theory. Information-theoretic model selection showed that overall species richness was explained primarily by the species area relationship. There was some support for a model with greater complexity than the equilibrium theory of island biogeography where the isolation of large patches resulted in greater species richness. Species richness of woodland-dwelling birds was best explained by the equilibrium hypothesis with partial landscape complementation by open-country species in isolated patches. Species richness within specific migratory strategies showed concomitant increases and no shifts in species composition along the patch area gradient. Our results indicate that many patterns of species richness

  16. Habitat Fragmentation can Modulate Drought Effects on the Plant-soil-microbial System in Mediterranean Holm Oak (Quercus ilex) Forests.

    PubMed

    Flores-Rentería, Dulce; Curiel Yuste, Jorge; Rincón, Ana; Brearley, Francis Q; García-Gil, Juan Carlos; Valladares, Fernando

    2015-05-01

    Ecological transformations derived from habitat fragmentation have led to increased threats to above-ground biodiversity. However, the impacts of forest fragmentation on soils and their microbial communities are not well understood. We examined the effects of contrasting fragment sizes on the structure and functioning of soil microbial communities from holm oak forest patches in two bioclimatically different regions of Spain. We used a microcosm approach to simulate the annual summer drought cycle and first autumn rainfall (rewetting), evaluating the functional response of a plant-soil-microbial system. Forest fragment size had a significant effect on physicochemical characteristics and microbial functioning of soils, although the diversity and structure of microbial communities were not affected. The response of our plant-soil-microbial systems to drought was strongly modulated by the bioclimatic conditions and the fragment size from where the soils were obtained. Decreasing fragment size modulated the effects of drought by improving local environmental conditions with higher water and nutrient availability. However, this modulation was stronger for plant-soil-microbial systems built with soils from the northern region (colder and wetter) than for those built with soils from the southern region (warmer and drier) suggesting that the responsiveness of the soil-plant-microbial system to habitat fragmentation was strongly dependent on both the physicochemical characteristics of soils and the historical adaptation of soil microbial communities to specific bioclimatic conditions. This interaction challenges our understanding of future global change scenarios in Mediterranean ecosystems involving drier conditions and increased frequency of forest fragmentation.

  17. Higher temporal variability of forest breeding bird communities in fragmented landscapes

    USGS Publications Warehouse

    Boulinier, T.; Nichols, J.D.; Hines, J.E.; Sauer, J.R.; Flather, C.H.; Pollock, K.H.

    1998-01-01

    Understanding the relationship between animal community dynamics and landscape structure has become a priority for biodiversity conservation. In particular, predicting the effects of habitat destruction that confine species to networks of small patches is an important prerequisite to conservation plan development. Theoretical models that predict the occurrence of species in fragmented landscapes, and relationships between stability and diversity do exist. However, reliable empirical investigations of the dynamics of biodiversity have been prevented by differences in species detection probabilities among landscapes. Using long-term data sampled at a large spatial scale in conjunction with a capture-recapture approach, we developed estimates of parameters of community changes over a 22-year period for forest breeding birds in selected areas of the eastern United States. We show that forest fragmentation was associated not only with a reduced number of forest bird species, but also with increased temporal variability in the number of species. This higher temporal variability was associated with higher local extinction and turnover rates. These results have major conservation implications. Moreover, the approach used provides a practical tool for the study of the dynamics of biodiversity.

  18. Higher temporal variability of forest breeding bird communities in fragmented landscapes

    PubMed Central

    Boulinier, Thierry; Nichols, James D.; Hines, James E.; Sauer, John R.; Flather, Curtis H.; Pollock, Kenneth H.

    1998-01-01

    Understanding the relationship between animal community dynamics and landscape structure has become a priority for biodiversity conservation. In particular, predicting the effects of habitat destruction that confine species to networks of small patches is an important prerequisite to conservation plan development. Theoretical models that predict the occurrence of species in fragmented landscapes, and relationships between stability and diversity do exist. However, reliable empirical investigations of the dynamics of biodiversity have been prevented by differences in species detection probabilities among landscapes. Using long-term data sampled at a large spatial scale in conjunction with a capture-recapture approach, we developed estimates of parameters of community changes over a 22-year period for forest breeding birds in selected areas of the eastern United States. We show that forest fragmentation was associated not only with a reduced number of forest bird species, but also with increased temporal variability in the number of species. This higher temporal variability was associated with higher local extinction and turnover rates. These results have major conservation implications. Moreover, the approach used provides a practical tool for the study of the dynamics of biodiversity. PMID:9636178

  19. Loggers and Forest Fragmentation: Behavioral Models of Road Building in the Amazon Basin

    NASA Technical Reports Server (NTRS)

    Arima, Eugenio Y.; Walker, Robert T.; Perz, Stephen G.; Caldas, Marcellus

    2005-01-01

    Although a large literature now exists on the drivers of tropical deforestation, less is known about its spatial manifestation. This is a critical shortcoming in our knowledge base since the spatial pattern of land-cover change and forest fragmentation, in particular, strongly affect biodiversity. The purpose of this article is to consider emergent patterns of road networks, the initial proximate cause of fragmentation in tropical forest frontiers. Specifically, we address the road-building processes of loggers who are very active in the Amazon landscape. To this end, we develop an explanation of road expansions, using a positive approach combining a theoretical model of economic behavior with geographic information systems (GIs) software in order to mimic the spatial decisions of road builders. We simulate two types of road extensions commonly found in the Amazon basin in a region: showing the fishbone pattern of fragmentation. Although our simulation results are only partially successful, they call attention to the role of multiple agents in the landscape, the importance of legal and institutional constraints on economic behavior, and the power of GIs as a research tool.

  20. Impacts of forest fragmentation on species richness: a hierarchical approach to community modelling

    USGS Publications Warehouse

    Zipkin, Elise F.; DeWan, Amielle; Royle, J. Andrew

    2009-01-01

    1. Species richness is often used as a tool for prioritizing conservation action. One method for predicting richness and other summaries of community structure is to develop species-specific models of occurrence probability based on habitat or landscape characteristics. However, this approach can be challenging for rare or elusive species for which survey data are often sparse. 2. Recent developments have allowed for improved inference about community structure based on species-specific models of occurrence probability, integrated within a hierarchical modelling framework. This framework offers advantages to inference about species richness over typical approaches by accounting for both species-level effects and the aggregated effects of landscape composition on a community as a whole, thus leading to increased precision in estimates of species richness by improving occupancy estimates for all species, including those that were observed infrequently. 3. We developed a hierarchical model to assess the community response of breeding birds in the Hudson River Valley, New York, to habitat fragmentation and analysed the model using a Bayesian approach. 4. The model was designed to estimate species-specific occurrence and the effects of fragment area and edge (as measured through the perimeter and the perimeter/area ratio, P/A), while accounting for imperfect detection of species. 5. We used the fitted model to make predictions of species richness within forest fragments of variable morphology. The model revealed that species richness of the observed bird community was maximized in small forest fragments with a high P/A. However, the number of forest interior species, a subset of the community with high conservation value, was maximized in large fragments with low P/A. 6. Synthesis and applications. Our results demonstrate the importance of understanding the responses of both individual, and groups of species, to environmental heterogeneity while illustrating the utility

  1. Deforestation and fragmentation of natural forests in the upper Changhua watershed, Hainan, China: implications for biodiversity conservation.

    PubMed

    Zhai, De-Li; Cannon, Charles H; Dai, Zhi-Cong; Zhang, Cui-Ping; Xu, Jian-Chu

    2015-01-01

    Hainan, the largest tropical island in China, belongs to the Indo-Burma biodiversity hotspot. The Changhua watershed is a center of endemism for plants and birds and the cradle of Hainan's main rivers. However, this area has experienced recent and ongoing deforestation and habitat fragmentation. To quantify habitat loss and fragmentation of natural forests, as well as the land-cover changes in the Changhua watershed, we analyzed Landsat images obtained in 1988, 1995, and 2005. Land-cover dynamics analysis showed that natural forests increased in area (97,909 to 104,023 ha) from 1988 to 1995 but decreased rapidly to 76,306 ha over the next decade. Rubber plantations increased steadily throughout the study period while pulp plantations rapidly expanded after 1995. Similar patterns of land cover change were observed in protected areas, indicating a lack of enforcement. Natural forests conversion to rubber and pulp plantations has a general negative effect on biodiversity, primarily through habitat fragmentation. The fragmentation analysis showed that natural forests area was reduced and patch number increased, while patch size and connectivity decreased. These land-cover changes threatened local biodiversity, especially island endemic species. Both natural forests losses and fragmentation should be stopped by strict enforcement to prevent further damage. Preserving the remaining natural forests and enforcing the status of protected areas should be a management priority to maximize the watershed's biodiversity conservation value.

  2. Habitat Degradation and Seasonality Affect Physiological Stress Levels of Eulemur collaris in Littoral Forest Fragments

    PubMed Central

    Balestri, Michela; Barresi, Marta; Campera, Marco; Serra, Valentina; Ramanamanjato, Jean Baptiste; Heistermann, Michael; Donati, Giuseppe

    2014-01-01

    The littoral forest on sandy soil is among the most threatened habitats in Madagascar and, as such, it represents a hot-spot within a conservation hot-spot. Assessing the health of the resident lemur fauna is not only critical for the long-term viability of these populations, but also necessary for the future re-habilitation of this unique habitat. Since the Endangered collared brown lemur, Eulemur collaris, is the largest seed disperser of the Malagasy south-eastern littoral forest its survival in this habitat is crucial. In this study we compared fecal glucocorticoid metabolite (fGCM) levels, a measure of physiological stress and potential early indicator of population health, between groups of collared brown lemurs living in a degraded forest fragment and groups occurring in a more preserved area. For this, we analysed 279 fecal samples collected year-round from 4 groups of collared brown lemurs using a validated 11-oxoetiocholanolone enzyme immunoassay and tested if fGCM levels were influenced by reproductive stages, phenological seasons, sex, and habitat degradation. The lemurs living in the degraded forest had significantly higher fGCM levels than those living in the more preserved area. In particular, the highest fGCM levels were found during the mating season in all animals and in females during gestation in the degraded forest. Since mating and gestation are both occurring during the lean season in the littoral forest, these results likely reflect a combination of ecological and reproductive pressures. Our findings provide a clear indication that habitat degradation has additive effects to the challenges found in the natural habitat. Since increased stress hormone output may have long-term negative effects on population health and reproduction, our data emphasize the need for and may add to the development of effective conservation plans for the species. PMID:25229944

  3. Habitat degradation and seasonality affect physiological stress levels of Eulemur collaris in littoral forest fragments.

    PubMed

    Balestri, Michela; Barresi, Marta; Campera, Marco; Serra, Valentina; Ramanamanjato, Jean Baptiste; Heistermann, Michael; Donati, Giuseppe

    2014-01-01

    The littoral forest on sandy soil is among the most threatened habitats in Madagascar and, as such, it represents a hot-spot within a conservation hot-spot. Assessing the health of the resident lemur fauna is not only critical for the long-term viability of these populations, but also necessary for the future re-habilitation of this unique habitat. Since the Endangered collared brown lemur, Eulemur collaris, is the largest seed disperser of the Malagasy south-eastern littoral forest its survival in this habitat is crucial. In this study we compared fecal glucocorticoid metabolite (fGCM) levels, a measure of physiological stress and potential early indicator of population health, between groups of collared brown lemurs living in a degraded forest fragment and groups occurring in a more preserved area. For this, we analysed 279 fecal samples collected year-round from 4 groups of collared brown lemurs using a validated 11-oxoetiocholanolone enzyme immunoassay and tested if fGCM levels were influenced by reproductive stages, phenological seasons, sex, and habitat degradation. The lemurs living in the degraded forest had significantly higher fGCM levels than those living in the more preserved area. In particular, the highest fGCM levels were found during the mating season in all animals and in females during gestation in the degraded forest. Since mating and gestation are both occurring during the lean season in the littoral forest, these results likely reflect a combination of ecological and reproductive pressures. Our findings provide a clear indication that habitat degradation has additive effects to the challenges found in the natural habitat. Since increased stress hormone output may have long-term negative effects on population health and reproduction, our data emphasize the need for and may add to the development of effective conservation plans for the species.

  4. Contrasting Patterns of Species Richness and Functional Diversity in Bird Communities of East African Cloud Forest Fragments

    PubMed Central

    Ulrich, Werner; Lens, Luc; Tobias, Joseph A.; Habel, Jan C.

    2016-01-01

    Rapid fragmentation and degradation of large undisturbed habitats constitute major threats to biodiversity. Several studies have shown that populations in small and highly isolated habitat patches are prone to strong environmental and demographic stochasticity and increased risk of extinction. Based on community assembly theory, we predict recent rapid forest fragmentation to cause a decline in species and functional guild richness of forest birds combined with a high species turnover among habitat patches, and well defined dominance structures, if competition is the major driver of community assembly. To test these predictions, we analysed species co-occurrence, nestedness, and competitive strength to infer effects of interspecific competition, habitat structure, and species′ traits on the assembly of bird species communities from 12 cloud forest fragments in southern Kenya. Our results do not point to a single ecological driver of variation in species composition. Interspecific competition does not appear to be a major driver of species segregation in small forest patches, while its relative importance appears to be higher in larger ones, which may be indicative for a generic shift from competition-dominated to colonisation-driven community structure with decreasing fragment size. Functional trait diversity was independent of fragment size after controlling for species richness. As fragmentation effects vary among feeding guilds and habitat generalists, in particular, tend to decline in low quality forest patches, we plead for taking species ecology fully into account when predicting tropical community responses to habitat change. PMID:27855174

  5. Contrasting Patterns of Species Richness and Functional Diversity in Bird Communities of East African Cloud Forest Fragments.

    PubMed

    Ulrich, Werner; Lens, Luc; Tobias, Joseph A; Habel, Jan C

    2016-01-01

    Rapid fragmentation and degradation of large undisturbed habitats constitute major threats to biodiversity. Several studies have shown that populations in small and highly isolated habitat patches are prone to strong environmental and demographic stochasticity and increased risk of extinction. Based on community assembly theory, we predict recent rapid forest fragmentation to cause a decline in species and functional guild richness of forest birds combined with a high species turnover among habitat patches, and well defined dominance structures, if competition is the major driver of community assembly. To test these predictions, we analysed species co-occurrence, nestedness, and competitive strength to infer effects of interspecific competition, habitat structure, and species' traits on the assembly of bird species communities from 12 cloud forest fragments in southern Kenya. Our results do not point to a single ecological driver of variation in species composition. Interspecific competition does not appear to be a major driver of species segregation in small forest patches, while its relative importance appears to be higher in larger ones, which may be indicative for a generic shift from competition-dominated to colonisation-driven community structure with decreasing fragment size. Functional trait diversity was independent of fragment size after controlling for species richness. As fragmentation effects vary among feeding guilds and habitat generalists, in particular, tend to decline in low quality forest patches, we plead for taking species ecology fully into account when predicting tropical community responses to habitat change.

  6. Phylogeography of four frog species in forest fragments of northeastern Brazil--a preliminary study.

    PubMed

    Carnaval, Ana Carolina O Q

    2002-11-01

    I contrast mitochondrial DNA genealogies based on 612 bp of the cytochrome b gene across four co-distributed species of frogs in Northeastern Brazil. They are Hyla albomarginata, Hyla branneri, Proceratophrys boiei, and Scinax nebulosus. Samples were collected from the core or edge of six rainforest remnants in the states of Pernambuco and Alagoas. Three fragments are located within the humid Atlantic Forest morphoclimatic domain (municipalities of Cabo de Santo Agostinho, Ibateguara, and Jaqueira), two are located in the transition zone between the Atlantic Forest domain and the semi-arid Caatinga (Caruaru and Timbaúba), and one is found within the Caatinga (Brejo da Madre de Deus). Results show that local patterns and levels of genetic diversity are influenced by taxon-specific habitat requirements. Populations of the montane, closed-canopy species P. boiei show strong geographical structure, reflecting barriers to gene flow that predate human-driven habitat destruction. Species occurring along forest edges, such as H. albomarginata and S. nebulosus, show genetic patterns similar to those of P. boiei, but lower levels of genetic divergence. The more generalist Hyla branneri shows no geographic pattern. The data are in agreement with distribution and fossil data gathered for other groups of organisms, suggesting that mesic forests occupied the currently arid Caatinga in the recent past.

  7. Removal rates of native and exotic dung by dung beetles (Scarabaeidae: Scarabaeinae) in a fragmented tropical rain forest.

    PubMed

    Amézquita, Sandra; Favila, Mario E

    2010-04-01

    Many studies have evaluated the effect of forest fragmentation on dung beetle assemblage structure. However, few have analyzed how forest fragmentation affects the processes carried out by these insects in tropical forests where their food sources consist mainly of dung produced by native herbivore mammals. With the conversion of forests to pastures, cattle dung has become an exotic alternative and abundant food for dung beetles. This study compares dung removal rates of native (monkey) and exotic (cow) dung in different-sized fragments of tropical rain forests, during the dry and rainy seasons at the Los Tuxtlas Biosphere Reserve. Dung removal rates were affected by season, dung type, and the interaction between resource type and season. During the dry season, the removal rates of monkey dung were somewhat similar than during the rainy season, whereas the removal rates of cow dung were much higher during the rainy season. Dung beetle biomass and species richness were almost three times greater in monkey dung than in cow dung. Monkey dung attracted species belonging to the dweller, roller, and tunneler guilds; cow dung attracted mostly tunnelers. Therefore, the use of exotic dung may result in a biased misconception of the rates of dung removal in tropical forest and an underestimation of dung beetle diversity. This study highlights the importance of working with natural tropical forest resources when attempting to identify realistic tendencies concerning processes in natural habitats and those modified by fragmentation and by other human activities.

  8. Factors Associated with the Seroprevalence of Leishmaniasis in Dogs Living around Atlantic Forest Fragments

    PubMed Central

    Curi, Nelson Henrique de Almeida; Paschoal, Ana Maria de Oliveira; Massara, Rodrigo Lima; Marcelino, Andreza Pain; Ribeiro, Adriana Aparecida; Passamani, Marcelo; Demétrio, Guilherme Ramos; Chiarello, Adriano Garcia

    2014-01-01

    Canine visceral leishmaniasis is an important zoonosis in Brazil. However, infection patterns are unknown in some scenarios such as rural settlements around Atlantic Forest fragments. Additionally, controversy remains over risk factors, and most identified patterns of infection in dogs have been found in urban areas. We conducted a cross-sectional epidemiological survey to assess the prevalence of leishmaniasis in dogs through three different serological tests, and interviews with owners to assess features of dogs and households around five Atlantic Forest remnants in southeastern Brazil. We used Generalized Linear Mixed Models and Chi-square tests to detect associations between prevalence and variables that might influence Leishmania infection, and a nearest neighbor dispersion analysis to assess clustering in the spatial distribution of seropositive dogs. Our findings showed an average prevalence of 20% (ranging from 10 to 32%) in dogs. Nearly 40% (ranging from 22 to 55%) of households had at least one seropositive dog. Some individual traits of dogs (height, sterilization, long fur, age class) were found to positively influence the prevalence, while some had negative influence (weight, body score, presence of ectoparasites). Environmental and management features (number of cats in the households, dogs with free-ranging behavior) also entered models as negative associations with seropositivity. Strong and consistent negative (protective) influences of the presence of chickens and pigs in dog seropositivity were detected. Spatial clustering of cases was detected in only one of the five study sites. The results showed that different risk factors than those found in urban areas may drive the prevalence of canine leishmaniasis in farm/forest interfaces, and that humans and wildlife risk infection in these areas. Domestic dog population limitation by gonadectomy, legal restriction of dog numbers per household and owner education are of the greatest importance for the

  9. Mites associated with sugarcane crop and with native trees from adjacent Atlantic forest fragment in Brazil.

    PubMed

    Duarte, Mércia E; Navia, Denise; dos Santos, Lucas R; Rideiqui, Pedro J S; Silva, Edmilson S

    2015-08-01

    In some Brazilian regions the Atlantic forest biome is currently restrict to fragments occurring amid monocultures, as sugarcane crops in the Northeast region. Important influence of forest remnants over mite fauna of permanent crops have been showed, however it has been poorly explored on annual crops. The first step for understanding ecological relationship in an agricultural systems is known its composition. The objective of this study was to investigate the plant-inhabiting mite fauna associated with sugarcane crop (Saccharum officinarum L.) (Poaceae) and caboatã (Cupania oblongifolia Mart.) (Sapindaceae) trees in the state of Alagoas, Brazil. Sugarcane stalks and sugarcane and caboatã apical, middle and basal leaves were sampled. A total of 2565 mites were collected from sugarcane and classified into seven families of Trombidiformes and Mesostigmata orders, with most individuals belonging to the Eriophyidae, Tetranychidae and Tarsonemidae families. Among predatory mites, the Phytoseiidae were the most common. A total of 1878 mites were found on C. oblongifolia and classified into 13 families of Trombidiformes and Mesostigmata orders. The most abundant phytophagous mite family on caboatã was also Eriophyidae. In contrast to sugarcane, Ascidae was the most common predatory mite family observed in caboatã. No phytophagous species were common to both sugarcane and C. oblongifolia. However two predatory mites were shared between host plants. Although mites associated with only one native species in the forest fragment were evaluated in this study, our preliminary results suggest Atlantic forest native vegetation can present an important role in the sugarcane agricultural system as a source of natural enemies.

  10. Geospatial characterization of deforestation, fragmentation and forest fires in Telangana state, India: conservation perspective.

    PubMed

    Sudhakar Reddy, C; Vazeed Pasha, S; Jha, C S; Dadhwal, V K

    2015-07-01

    Conservation of biodiversity has been put to the highest priority throughout the world. The process of identifying threatened ecosystems will search for different drivers related to biodiversity loss. The present study aimed to generate spatial information on deforestation and ecological degradation indicators of fragmentation and forest fires using systematic conceptual approach in Telangana state, India. Identification of ecosystems facing increasing vulnerability can help to safeguard the extinctions of species and useful for conservation planning. The technological advancement of satellite remote sensing and Geographical Information System has increased greatly in assessment and monitoring of ecosystem-level changes. The areas of threat were identified by creating grid cells (5 × 5 km) in Geographical Information System (GIS). Deforestation was assessed using multi-source data of 1930, 1960, 1975, 1985, 1995, 2005 and 2013. The forest cover of 40,746 km(2), 29,299 km(2), 18,652 km(2), 18,368 km(2), 18,006 km(2), 17,556 km(2) and 17,520 km(2) was estimated during 1930, 1960, 1975, 1985, 1995, 2005 and 2013, respectively. Historical evaluation of deforestation revealed that major changes had occurred in forests of Telangana and identified 1095 extinct, 397 critically endangered, 523 endangered and 311 vulnerable ecosystem grid cells. The fragmentation analysis has identified 307 ecosystem grid cells under critically endangered status. Forest burnt area information was extracted using AWiFS data of 2005 to 2014. Spatial analysis indicates total fire-affected forest in Telangana as 58.9% in a decadal period. Conservation status has been recorded depending upon values of threat for each grid, which forms the basis for conservation priority hotspots. Of existing forest, 2.1% grids had severe ecosystem collapse and had been included under the category of conservation priority hotspot-I, followed by 27.2% in conservation priority hotspot-II and 51.5% in conservation

  11. Forest fragmentation reduces parasitism via species loss at multiple trophic levels.

    PubMed

    Fenoglio, Maria Silvina; Srivastava, Diane; Valladares, Graciela; Cagnolo, Luciano; Salvo, Adriana

    2012-11-01

    Although there is accumulating evidence from artificially assembled communities that reductions of species diversity result in diminished ecosystem functioning, it is not yet clear how real-world changes in diversity affect the flow of energy between trophic levels in multi-trophic contexts. In central Argentina, forest fragmentation has led to species loss of plants, herbivore and parasitoid insects, decline in trophic processes (herbivory and parasitism), and food web contraction. Here we examine if and how loss of parasitoid species following fragmentation causes decreased parasitism rates, by analyzing food webs of leaf miners and parasitoids from 19 forest fragments of decreasing size. We asked three questions: Do reductions in parasitoid richness following fragmentation directly or indirectly affect parasitism rate? Are changes in community parasitism rate driven by changes in the parasitism rate of individual leaf miner species, or changes in leaf miner composition, or both? Which traits of species determine the effects of food web change on parasitism rates? We found that habitat loss initiated a bottom-up cascade of extinctions from plants to leaf miners to parasitoids, with reductions in parasitoid richness ultimately driving decreases in parasitism rates. This relationship between parasitoid richness and parasitism depended on changes in the relative abundance (but not occurrence) of leaf miners such that parasitoid-rich fragments were dominated by leaf miner species that supported high rates of parasitism. Surprisingly, we found that only a small subset of species in the food web could account for much of the increase in parasitism with parasitoid richness: lepidopteran miners that attained exceptionally high densities in some fragments and their largely specialist parasitoids. How specialized a parasitoid is, and the relative abundance of leaf miners, had important effects on the diversity-parasitism rate relationship, but not other leaf miner traits

  12. Hardwood snag fragmentation in a pine-oak forest of southeastern Arkansas

    SciTech Connect

    Cain, M.D.

    1996-12-31

    Because snags are importnat for forest wildlife as breeding, roosting and foraging sites, resource managers who wish to maintain this component in forest stands need to be aware of snag fragmentation rates. Measurements were taken in uneven-aged pine-hardwood standards in southeastern Arkansas to determine fragmentation rates for hardwood snags 2 to 6 yr after stem injection with herbicides. Crown and bole condition of snags were also assessed. Pinus eschinata Mill. and P. taeda L. were the dominant overstory components and were udisturbed. Quercus spp. accounted for 91% of hardwoods greater than 25 cm dbh. Since small diameter snags deteriorated first, snag diameter distributions changed from uneven-sized to even-sized structure as time since mortality increased. Within 3 yr of injection, 57% of snag boles had broken below crown height. Number of wildlife cavities per snag increased with time since mortality. At 6 yr after injection, 44% of residual snags had evidence of wildlife cavities. Less than 50% of hardwoods less then 25 cm dbh were still standing 5 yr after herbicide injection.

  13. Behavioral and physiological responses to fruit availability of spider monkeys ranging in a small forest fragment

    PubMed Central

    Rimbach, Rebecca; Link, Andrés; Montes-Rojas, Andrés; Di Fiore, Anthony; Heistermann, Michael; Heymann, Eckhard W

    2014-01-01

    Numerous animal species currently experience habitat loss and fragmentation. This might result in behavioral and dietary adjustments, especially because fruit availability is frequently reduced in fragments. Food scarcity can result in elevated physiological stress levels, and chronic stress often has detrimental effects on individuals. Some animal species exhibit a high degree of fission–fusion dynamics, and theory predicts that these species reduce intragroup feeding competition by modifying their subgroup size according to resource availability. Until now, however, there have been few studies on how species with such fission–fission dynamics adjust their grouping patterns and social behavior in small fragments or on how food availability influences their stress levels. We collected data on fruit availability, feeding behavior, stress hormone levels (measured through fecal glucocorticoid metabolites (FGCM)), subgroup size, and aggression for two groups of brown spider monkeys (Ateles hybridus) in a small forest fragment in Colombia and examined whether fruit availability influences these variables. Contrary to our predictions, spider monkeys ranged in smaller subgroups, had higher FGCM levels and higher aggression rates when fruit availability was high compared to when it was low. The atypical grouping pattern of the study groups seems to be less effective at mitigating contest competition over food resources than more typical fission–fusion patterns. Overall, our findings illustrate that the relationship between resource availability, grouping patterns, aggression rates, and stress levels can be more complex than assumed thus far. Additional studies are needed to investigate the long-term consequences on the health and persistence of spider monkeys in fragmented habitats. PMID:24820229

  14. BIOFRAG – a new database for analyzing BIOdiversity responses to forest FRAGmentation

    PubMed Central

    Pfeifer, Marion; Lefebvre, Veronique; Gardner, Toby A; Arroyo-Rodriguez, Victor; Baeten, Lander; Banks-Leite, Cristina; Barlow, Jos; Betts, Matthew G; Brunet, Joerg; Cerezo, Alexis; Cisneros, Laura M; Collard, Stuart; D'Cruze, Neil; da Silva Motta, Catarina; Duguay, Stephanie; Eggermont, Hilde; Eigenbrod, Felix; Hadley, Adam S; Hanson, Thor R; Hawes, Joseph E; Heartsill Scalley, Tamara; Klingbeil, Brian T; Kolb, Annette; Kormann, Urs; Kumar, Sunil; Lachat, Thibault; Lakeman Fraser, Poppy; Lantschner, Victoria; Laurance, William F; Leal, Inara R; Lens, Luc; Marsh, Charles J; Medina-Rangel, Guido F; Melles, Stephanie; Mezger, Dirk; Oldekop, Johan A; Overal, William L; Owen, Charlotte; Peres, Carlos A; Phalan, Ben; Pidgeon, Anna M; Pilia, Oriana; Possingham, Hugh P; Possingham, Max L; Raheem, Dinarzarde C; Ribeiro, Danilo B; Ribeiro Neto, Jose D; Douglas Robinson, W; Robinson, Richard; Rytwinski, Trina; Scherber, Christoph; Slade, Eleanor M; Somarriba, Eduardo; Stouffer, Philip C; Struebig, Matthew J; Tylianakis, Jason M; Tscharntke, Teja; Tyre, Andrew J; Urbina Cardona, Jose N; Vasconcelos, Heraldo L; Wearn, Oliver; Wells, Konstans; Willig, Michael R; Wood, Eric; Young, Richard P; Bradley, Andrew V; Ewers, Robert M

    2014-01-01

    Habitat fragmentation studies have produced complex results that are challenging to synthesize. Inconsistencies among studies may result from variation in the choice of landscape metrics and response variables, which is often compounded by a lack of key statistical or methodological information. Collating primary datasets on biodiversity responses to fragmentation in a consistent and flexible database permits simple data retrieval for subsequent analyses. We present a relational database that links such field data to taxonomic nomenclature, spatial and temporal plot attributes, and environmental characteristics. Field assessments include measurements of the response(s) (e.g., presence, abundance, ground cover) of one or more species linked to plots in fragments within a partially forested landscape. The database currently holds 9830 unique species recorded in plots of 58 unique landscapes in six of eight realms: mammals 315, birds 1286, herptiles 460, insects 4521, spiders 204, other arthropods 85, gastropods 70, annelids 8, platyhelminthes 4, Onychophora 2, vascular plants 2112, nonvascular plants and lichens 320, and fungi 449. Three landscapes were sampled as long-term time series (>10 years). Seven hundred and eleven species are found in two or more landscapes. Consolidating the substantial amount of primary data available on biodiversity responses to fragmentation in the context of land-use change and natural disturbances is an essential part of understanding the effects of increasing anthropogenic pressures on land. The consistent format of this database facilitates testing of generalizations concerning biologic responses to fragmentation across diverse systems and taxa. It also allows the re-examination of existing datasets with alternative landscape metrics and robust statistical methods, for example, helping to address pseudo-replication problems. The database can thus help researchers in producing broad syntheses of the effects of land use. The database

  15. BIOFRAG - a new database for analyzing BIOdiversity responses to forest FRAGmentation.

    PubMed

    Pfeifer, Marion; Lefebvre, Veronique; Gardner, Toby A; Arroyo-Rodriguez, Victor; Baeten, Lander; Banks-Leite, Cristina; Barlow, Jos; Betts, Matthew G; Brunet, Joerg; Cerezo, Alexis; Cisneros, Laura M; Collard, Stuart; D'Cruze, Neil; da Silva Motta, Catarina; Duguay, Stephanie; Eggermont, Hilde; Eigenbrod, Felix; Hadley, Adam S; Hanson, Thor R; Hawes, Joseph E; Heartsill Scalley, Tamara; Klingbeil, Brian T; Kolb, Annette; Kormann, Urs; Kumar, Sunil; Lachat, Thibault; Lakeman Fraser, Poppy; Lantschner, Victoria; Laurance, William F; Leal, Inara R; Lens, Luc; Marsh, Charles J; Medina-Rangel, Guido F; Melles, Stephanie; Mezger, Dirk; Oldekop, Johan A; Overal, William L; Owen, Charlotte; Peres, Carlos A; Phalan, Ben; Pidgeon, Anna M; Pilia, Oriana; Possingham, Hugh P; Possingham, Max L; Raheem, Dinarzarde C; Ribeiro, Danilo B; Ribeiro Neto, Jose D; Douglas Robinson, W; Robinson, Richard; Rytwinski, Trina; Scherber, Christoph; Slade, Eleanor M; Somarriba, Eduardo; Stouffer, Philip C; Struebig, Matthew J; Tylianakis, Jason M; Tscharntke, Teja; Tyre, Andrew J; Urbina Cardona, Jose N; Vasconcelos, Heraldo L; Wearn, Oliver; Wells, Konstans; Willig, Michael R; Wood, Eric; Young, Richard P; Bradley, Andrew V; Ewers, Robert M

    2014-05-01

    Habitat fragmentation studies have produced complex results that are challenging to synthesize. Inconsistencies among studies may result from variation in the choice of landscape metrics and response variables, which is often compounded by a lack of key statistical or methodological information. Collating primary datasets on biodiversity responses to fragmentation in a consistent and flexible database permits simple data retrieval for subsequent analyses. We present a relational database that links such field data to taxonomic nomenclature, spatial and temporal plot attributes, and environmental characteristics. Field assessments include measurements of the response(s) (e.g., presence, abundance, ground cover) of one or more species linked to plots in fragments within a partially forested landscape. The database currently holds 9830 unique species recorded in plots of 58 unique landscapes in six of eight realms: mammals 315, birds 1286, herptiles 460, insects 4521, spiders 204, other arthropods 85, gastropods 70, annelids 8, platyhelminthes 4, Onychophora 2, vascular plants 2112, nonvascular plants and lichens 320, and fungi 449. Three landscapes were sampled as long-term time series (>10 years). Seven hundred and eleven species are found in two or more landscapes. Consolidating the substantial amount of primary data available on biodiversity responses to fragmentation in the context of land-use change and natural disturbances is an essential part of understanding the effects of increasing anthropogenic pressures on land. The consistent format of this database facilitates testing of generalizations concerning biologic responses to fragmentation across diverse systems and taxa. It also allows the re-examination of existing datasets with alternative landscape metrics and robust statistical methods, for example, helping to address pseudo-replication problems. The database can thus help researchers in producing broad syntheses of the effects of land use. The database

  16. Arthropods on plants in a fragmented Neotropical dry forest: a functional analysis of area loss and edge effects.

    PubMed

    González, Ezequiel; Salvo, Adriana; Valladares, Graciela

    2015-02-01

    Loss and fragmentation of natural ecosystems are widely recognized as the most important threats to biodiversity conservation, with Neotropical dry forests among the most endangered ecosystems. Area and edge effects are major factors in fragmented landscapes. Here, we examine area and edge effects and their interaction, on ensembles of arthropods associated to native vegetation in a fragmented Chaco Serrano forest. We analyzed family richness and community composition of herbivores, predators, and parasitoids on three native plant species in 12 fragments of varying size and at edge/interior positions. We also looked for indicator families by using Indicator Species Analysis. Loss of family richness with the reduction of forest fragment area was observed for the three functional groups, with similar magnitude. Herbivores were richer at the edges without interaction between edge and area effects, whereas predators were not affected by edge/interior position and parasitoid richness showed an interaction between area and position, with a steeper area slope at the edges. Family composition of herbivore, predator, and parasitoid assemblages was also affected by forest area and/or edge/interior situation. We found three indicator families for large remnants and five for edges. Our results support the key role of forest area for conservation of arthropods taxonomic and functional diversity in a highly threatened region, and emphasize the need to understand the interactions between area and edge effects on such diversity.

  17. Bryophytes in fragments of Terra Firme forest on the great curve of the Xingu River, Pará state, Brazil.

    PubMed

    Pantoja, A C C; Ilkiu-Borges, A L; Tavares-Martins, A C C; Garcia, E T

    2015-08-01

    Microclimatic conditions of tropical forest favour the high richness of bryophytes, which by being sensitive to environmental changes, are important indicators of habitat conditions. The aim of this study was to determine the richness and species composition of the bryophyte flora in fragments of terra firme forest on the great curve of the Xingu River, Pará state, Brazil. The collections were made in August and September 2012 in 14 fragments, in which were installed two plots per fragment, one at the edge and one inside, measuring 10 × 10 m each. The results showed 77 species in 45 genera and 18 families. Lejeunea setiloba Spruce and Marchesinia brachiata (Sw.) Schiffn. are new records for Pará state. The richness families in this study were the ones typically found in tropical forest surveys. A high richness of rare species in comparison to common ones, a pattern usually observed for plants in tropical forests was not reported in this study, probably due to historical fragmentation and disturbance in the area. The richness and species composition were determined mainly by the physiognomic characteristics of the studied forest fragments.

  18. Effects of Habitat Structure and Fragmentation on Diversity and Abundance of Primates in Tropical Deciduous Forests in Bolivia.

    PubMed

    Pyritz, Lennart W; Büntge, Anna B S; Herzog, Sebastian K; Kessler, Michael

    2010-10-01

    Habitat structure and anthropogenic disturbance are known to affect primate diversity and abundance. However, researchers have focused on lowland rain forests, whereas endangered deciduous forests have been neglected. We aimed to investigate the relationships between primate diversity and abundance and habitat parameters in 10 deciduous forest fragments southeast of Santa Cruz, Bolivia. We obtained primate data via line-transect surveys and visual and acoustic observations. In addition, we assessed the vegetation structure (canopy height, understory density), size, isolation time, and surrounding forest area of the fragments. We interpreted our results in the context of the historical distribution data for primates in the area before fragmentation and interviews with local people. We detected 5 of the 8 historically observed primate species: Alouatta caraya, Aotus azarae boliviensis, Callithrix melanura, Callicebus donacophilus, and Cebus libidinosus juruanus. Total species number and detection rates decreased with understory density. Detection rates also negatively correlated with forest areas in the surroundings of a fragment, which may be due to variables not assessed, i.e., fragment shape, distance to nearest town. Observations for Alouatta and Aotus were too few to conduct further statistics. Cebus and Callicebus were present in 90% and 70% of the sites, respectively, and their density did not correlate with any of the habitat variables assessed, signaling high ecological plasticity and adaptability to anthropogenic impact in these species. Detections of Callithrix were higher in areas with low forest strata. Our study provides baseline data for future fragmentation studies in Neotropical dry deciduous forests and sets a base for specific conservation measures.

  19. Effects of Habitat Structure and Fragmentation on Diversity and Abundance of Primates in Tropical Deciduous Forests in Bolivia

    PubMed Central

    Büntge, Anna B. S.; Herzog, Sebastian K.; Kessler, Michael

    2010-01-01

    Habitat structure and anthropogenic disturbance are known to affect primate diversity and abundance. However, researchers have focused on lowland rain forests, whereas endangered deciduous forests have been neglected. We aimed to investigate the relationships between primate diversity and abundance and habitat parameters in 10 deciduous forest fragments southeast of Santa Cruz, Bolivia. We obtained primate data via line-transect surveys and visual and acoustic observations. In addition, we assessed the vegetation structure (canopy height, understory density), size, isolation time, and surrounding forest area of the fragments. We interpreted our results in the context of the historical distribution data for primates in the area before fragmentation and interviews with local people. We detected 5 of the 8 historically observed primate species: Alouatta caraya, Aotus azarae boliviensis, Callithrix melanura, Callicebus donacophilus, and Cebus libidinosus juruanus. Total species number and detection rates decreased with understory density. Detection rates also negatively correlated with forest areas in the surroundings of a fragment, which may be due to variables not assessed, i.e., fragment shape, distance to nearest town. Observations for Alouatta and Aotus were too few to conduct further statistics. Cebus and Callicebus were present in 90% and 70% of the sites, respectively, and their density did not correlate with any of the habitat variables assessed, signaling high ecological plasticity and adaptability to anthropogenic impact in these species. Detections of Callithrix were higher in areas with low forest strata. Our study provides baseline data for future fragmentation studies in Neotropical dry deciduous forests and sets a base for specific conservation measures. PMID:20949116

  20. Forest fragments as barriers to fruit fly dispersal: Anastrepha (Diptera: Tephritidae) populations in orchards and adjacent forest fragments in Puerto Rico.

    PubMed

    Jenkins, David A; Kendra, Paul E; Van Bloem, Skip; Whitmire, Stefanie; Mizell, Russ; Goenaga, Ricardo

    2013-04-01

    McPhail-type traps baited with ammonium acetate and putrescine were used to monitor populations of Anastrepha obliqua (Macquart) and Anastrepha suspensa (Loew) in two orchards with hosts of these flies (mango, Mangifera indica L., and carambola, Averrhoa carambola L.), as well as in forest fragments bordering these orchards. Contour maps were constructed to measure population distributions in and around orchards. Our results indicate that Anastrepha populations are focused around host fruit in both space and time, that traps do not draw fruit flies away from hosts, even when placed within 15 m of the host, and that lures continue to function for 6 mo in the field. The contour mapping analyses reveal that populations of fruit flies are focused around ovipositional hosts. Although the trapping system does not have a very long effective sampling range, it is ideal, when used in combination with contour analyses, for assessing fine-scale (on the order of meters) population distributions, including identifying resources around which fly populations are focused or, conversely, assessing the effectiveness of management tools. The results are discussed as they pertain to monitoring and detecting Anastrepha spp. with the McPhail-type trap and ammonium acetate and putrescine baiting system and the dispersal of these flies within Puerto Rico.

  1. Deforestation and Forest Fragmentation in South Ecuador since the 1970s – Losing a Hotspot of Biodiversity

    PubMed Central

    Tapia-Armijos, María Fernanda; Homeier, Jürgen; Espinosa, Carlos Iván; Leuschner, Christoph; de la Cruz, Marcelino

    2015-01-01

    Deforestation and fragmentation are major components of global change; both are contributing to the rapid loss of tropical forest area with important implications for ecosystem functioning and biodiversity conservation. The forests of South Ecuador are a biological ‘hotspot’ due to their high diversity and endemism levels. We examined the deforestation and fragmentation patterns in this area of high conservation value using aerial photographs and Aster satellite scenes. The registered annual deforestation rates of 0.75% (1976–1989) and 2.86% (1989–2008) for two consecutive survey periods, the decreasing mean patch size and the increasing isolation of the forest fragments show that the area is under severe threat. Approximately 46% of South Ecuador’s original forest cover had been converted by 2008 into pastures and other anthropogenic land cover types. We found that deforestation is more intense at lower elevations (premontane evergreen forest and shrubland) and that the deforestation front currently moves in upslope direction. Improved awareness of the spatial extent, dynamics and patterns of deforestation and forest fragmentation is urgently needed in biologically diverse areas like South Ecuador. PMID:26332681

  2. Associations between forest fragmentation patterns and geneticstructure in Pfrimer’s Parakeet (Pyrrhura pfrimeri), an endangered endemic to central Brazil’s dry forests

    USGS Publications Warehouse

    Haig, Susan M.; Miller, Leonard F.; Bianchi, Carlos; Mullins, Thomas D.

    2012-01-01

    When habitat becomes fragmented, populations of species may become increasingly isolated. In the absence of habitat corridors, genetic structure may develop and populations risk reductions in genetic diversity from increased genetic drift and inbreeding. Deforestation of the Cerrado biome of Brazil, particularly of the dry forests within the Parana˜ River Basin, has incrementally occurred since the 1970s and increased forest fragmentation within the region. We performed landscape genetic analyses of Pfrimer’s parakeet (Pyrrhura pfrimeri), a globally endangered endemic to the region, to determine if forest fragmentation patterns were associated with genetic structuring in this species. We used previously generated satellite imagery that identified the locations of Parana˜ River Basin forest fragments in 1977, 1993/94, and 2008. Behavioral data quantifying the affinity of Pfrimer’s parakeet for forest habitat was used to parameterize empirically derived landscape conductance surfaces. Though genetic structure was observed among Pfrimer’s parakeet populations, no association between genetic and geographic distance was detected. Likewise, least cost path lengths, circuit theorybased resistance distances, and a new measure of least cost path length complexity could not be conclusively associated with genetic structure patterns. Instead, a new quantity that encapsulated connection redundancy from the 1977 forest fragmentation data provided the clearest associations with pairwise genetic differentiation patterns (Jost’s D: r = 0.72, P = 0.006; FST: r = 0.741, P = 0.001). Our analyses suggest a 35-year or more lag between deforestation and its effect on genetic structure. Because 66 % of the Parana˜ River Basin has been deforested since 1977, we expect that genetic structure will increase substantially among Pfrimer’s Parakeet populations in the future, especially if fragmentation continues at its current pace.

  3. Characterizing fragmentation of the collective forests in southern China from multitemporal Landsat imagery: A case study from Kecheng district of Zhejiang province

    USGS Publications Warehouse

    Li, M.; Zhu, Z.; Vogelmann, J.E.; Xu, D.; Wen, W.; Liu, A.

    2011-01-01

    Tropical and subtropical forests provide important ecosystem goods and services including carbon sequestration and biodiversity conservation. These forests are facing increasing socioeconomic pressures and are rapidly being degraded and fragmented. This analysis focuses on the rate of change and patterns of fragmentation in a collective forest area in Zhejiang province, China, during the time period 1988–2005. The research consisted of two parts. The first was the development of general land cover maps and the identification of land cover changes by interpreting Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) time series imagery. The second part involved the computation and analysis of forest fragmentation metrics. For this portion of the study, fragmentation statistics were analyzed, and images were developed to depict forest fragmentation patterns and trends. Results revealed that there was a net loss of 7.8% in forest coverage, dropping from 66.8% in 1988 to 59.0% in 2005, primarily caused by agricultural expansion and poor forest management practices. An acceleration of forest fragmentation was also witnessed during the time intervals, which was evidenced by a decreasing trend in interior forest (57.2% in 1988, 55.0% in 1996 and 54.8% in 2005 respectively) coupled with the scales of the selected geospatial metrics. Continued forest loss and fragmentation are closely correlated with the existing political, educational, institutional and economic processes of contemporary China. To unlock the developmental potentials of the collective forests and to effectively mitigate the rate of forest loss and fragmentation, reforms of forest tenure and ecological immigration practices are recognized as a prospective alternative. The produced fragmentation maps further illustrates the importance of assessing landscape change history, especially the spatiotemporal patterns of forest fragments, when developing landscape level plans for biodiversity

  4. How large is large enough for insects? Forest fragmentation effects at three spatial scales

    NASA Astrophysics Data System (ADS)

    Ribas, C. R.; Sobrinho, T. G.; Schoereder, J. H.; Sperber, C. F.; Lopes-Andrade, C.; Soares, S. M.

    2005-02-01

    Several mechanisms may lead to species loss in fragmented habitats, such as edge and shape effects, loss of habitat and heterogeneity. Ants and crickets were sampled in 18 forest remnants in south-eastern Brazil, to test whether a group of small remnants maintains the same insect species richness as similar sized large remnants, at three spatial scales. We tested hypotheses about alpha and gamma diversity to explain the results. Groups of remnants conserve as many species of ants as a single one. Crickets, however, showed a scale-dependent pattern: at small scales there was no significant or important difference between groups of remnants and a single one, while at the larger scale the group of remnants maintained more species. Alpha diversity (local species richness) was similar in a group of remnants and in a single one, at the three spatial scales, both for ants and crickets. Gamma diversity, however, varied both with taxa (ants and crickets) and spatial scale, which may be linked to insect mobility, remnant isolation, and habitat heterogeneity. Biological characteristics of the organisms involved have to be considered when studying fragmentation effects, as well as spatial scale at which it operates. Mobility of the organisms influences fragmentation effects, and consequently conservation strategies.

  5. Independent effects of fragmentation on forest songbirds: an organism-based approach.

    PubMed

    Betts, Matthew G; Forbes, Graham J; Diamond, Antony W; Taylor, Philip D

    2006-06-01

    fragmentation effects, particularly in forest mosaics where boundaries between patches and matrix are ambiguous. Our results indicate that manipulating landscape pattern may reduce negative impacts of habitat loss for Ovenbird, but not Blackburnian Warbler. We emphasize that most variance in the occurrence of both species was explained by local scale or landscape composition variables rather than variables reflecting landscape pattern.

  6. 4300-Year Old 'Glacier Forests', Southern Coast Mountains, British Columbia and their Global Context

    NASA Astrophysics Data System (ADS)

    Koch, J.

    2014-12-01

    Dendrochronology and radiocarbon dating of in situ and detrital wood have been utilized to date Holocene glacier fluctuations in Garibaldi Provincial Park and at the Pemberton Icefield in the southern Coast Mountains of British Columbia. Fieldwork at over 30 glaciers has been carried out since 2002. The focus of this paper is on wood that has been radiocarbon dated between 4500 and 4000 years ago, which has been found at six glaciers. At four glaciers the wood was washing out from beneath present-day glacier snouts. At Helm Glacier in Garibaldi Park thirteen detrital branches and stumps were recovered, and at West Squamish Glacier at the Pemberton Icefield seven detrital branches, stems, and stumps were sampled. Some of these samples had diameters of up to 40 cm and were up to 250 cm long, and thus are much larger than any living trees near the present treeline. Tree-ring analysis shows that these glaciers advanced into and over mature forests that had grown near present-day glacier margins for at least 135 years (Helm) and 357 years (W Squamish). Evidence for permanent snow and ice patches forming, as well as glaciers advancing beyond present-day extents at this time is found in the central Coast Mountains, Yukon Territory, Arctic Canada, Norway, and the Swiss Alps. Glacier advances of similar age have been reconstructed not only in western Canada, but also in Europe, Asia, South America, New Zealand, and Antarctica indicating the global nature of this event. A peak in ice-rafted debris in the North Atlantic about 4200 years ago may have been the result of reduced solar output, and based on Earth's position in the obliquity cycle glaciers should have started to expand 4000 years ago. These 'glacier forests' thus could provide a probable start date for Neoglaciation.

  7. Effect of habitat fragmentation on ranging behavior of white-headed langurs in limestone forests in Southwest China.

    PubMed

    Huang, Zhonghao; Yuan, Peisong; Huang, Henglian; Tang, Xiaoping; Xu, Weijian; Huang, Chengming; Zhou, Qihai

    2017-02-14

    The critically endangered white-headed langur (Trachypithecus leucocephalus) is confined to fragmented karst forests of southwest Guangxi Province, China. A lack of information on the influence of habitat fragmentation on langur behavior has prevented a comprehensive understanding of their ranging behavior and the development of effective langur conservation strategies. We collected comparative data on time budgets, daily path lengths, home range and diets of four langur groups inhabiting the lightly fragmented Fusui forest (G1, G2) and the more heavily fragmented Chongzuo forest (G3, G4). The aim was to explore the effect of this fragmentation on langur ranging behavior. Our results showed that the Fusui groups spent more time on moving and less time on feeding and playing than the Chongzuo groups. Daily path lengths were 472.4-536.1 m for the Fusui groups and 449.6-480.7 m for the Chongzuo groups, indicating no marked inter-site variation. The Fusui groups occupied much larger home ranges (23.8-33.8 ha) than the Chongzuo groups (14.5-15.8 ha). However, all groups had similar monthly home ranges. Diets significantly differed among langur groups. The Fusui groups consumed more young leaves and had much lower diet diversity compared with the Chongzuo groups. Our findings indicate that habitat fragmentation is one of the crucial determinants of white-headed langur ranging behavior because fragmentation reduces and restricts the home range. Langurs in fragmented habitat adopt an energy conservation strategy characterized by devoting more time to feeding and less time to moving, with a smaller home range and consumption of more plant species. We argue that linking fragmented forests with corridors should be considered a priority in a wider and comprehensive longer term langur population conservation and habitat management strategy.

  8. Impact of forest fragment size on the population structure of three palm species (Arecaceae) in the Brazilian Atlantic rainforest.

    PubMed

    Portela, Rita de Cássia Quitete; dos Santos, Flavio Antonio Maes

    2014-06-01

    The main threats to natural populations in terrestrial ecosystems have been widly recognized to be the habitat fragmentation and the exploitation of forest products. In this study, we compared the density of the populations and the structure of three tropical palm species, Astrocaryum aculeatissimum, Euterpe edulis and Geonoma schottiana. For this, we selected five forest fragments of different sizes (3 500ha, 2 400ha, 57ha, 21ha and 19ha) where palms were censused in nine 30 x 30m plots. We tracked the palms survival from 2005 to 2007, and recorded all new individuals encountered. Each individual was assigned in one of the five ontogenetic stages: seedling, infant, juvenile, immature and reproductive. The demographic structure of each palm species was analyzed and compared by a generalized linear model (GLM). The analysis was performed per palm species. The forest fragment area and the year of observation were explanatory variables, and the proportion of individuals in each ontogenetic class and palm density were response variables. The total number of individuals (from seedlings to reproductives, of all species) monitored was 6 450 in 2005, 7 268 in 2006, and 8 664 in 2007. The densities of two palm species were not influenced by the size of the fragment, but the population density of A. aculeatissimum was dependent on the size of the fragment: there were more individuals in the bigger than in the smaller forest fragments. The population structure of A. aculeatissimum, E. edulis, and G. schottiana was not altered in the smaller fragments, except the infants of G. schottiana. The main point to be drawn from the results found in this study is that the responses of density and population structure seem not to be dependent on fragment size, except for one species that resulted more abundant in bigger fragments.

  9. Climatic gradients and human development pressure determine spatial patterns of forest fragmentation in the Great Lakes basin, USA

    NASA Astrophysics Data System (ADS)

    Currie, W. S.; Hart, S.

    2015-12-01

    Over half of temperate forest area globally has been fragmented or deforested by human activities. Our objective was to gain insight into the combination of climatic, ecological, and social factors that control complex spatial patterns of forest cover and fragmentation at the regional scale. Our study area was the US portion of the land area of the Laurentian Great Lakes basin (USGL basin) of the Upper Midwest, USA, covering ca. 300,000 km2 and home to 25 million people. While this region was historically forested, today there are regional gradients in forest cover as well as complex spatial patterns of agriculture, human settlements, and tree cover. This includes large expanses of fragmented forests in the wildland-urban interface or the forest transition zone. We used structural equation modeling to test models of social and climatic-ecological factors to explain spatial patterns of forest cover and fragmentation. This is a model-driven approach to statistical analysis that is used to test proposed causal "structures" of direct and indirect relationships among variables. It is an innovative approach that makes use of large spatial datasets to test understanding. We assembled numerous spatial data layers at 1 km2 resolution across the USGL basin. We found that 64% to 75% of variance in tree cover and forest connectivity was explained through a relatively simple model combining climatic gradients and human development pressure. Human development pressure was best represented as a measurement model that explained 45% of variance in road density and 87% of housing unit density, while significantly explaining patterns of forest fragmentation. Climate could be represented by a single variable, temperature: where temperature was higher, tree cover and forest connectivity was lower due to human land use. Temperatures did not help to explain patterns of human development as roads and housing, but did affect forest fragmentation through land use as cropland. This suggests

  10. Effects of patch size and type of coffee matrix on ithomiine butterfly diversity and dispersal in cloud-forest fragments.

    PubMed

    Muriel, Sandra B; Kattan, Gustavo H

    2009-08-01

    Determining the permeability of different types of landscape matrices to animal movement is essential for conserving populations in fragmented landscapes. We evaluated the effects of habitat patch size and matrix type on diversity, isolation, and dispersal of ithomiine butterflies in forest fragments surrounded by coffee agroecosystems in the Colombian Andes. Because ithomiines prefer a shaded understory, we expected the highest diversity and abundance in large fragments surrounded by shade coffee and the lowest in small fragments surrounded by sun coffee. We also thought shade coffee would favor butterfly dispersal and immigration into forest patches. We marked 9675 butterflies of 39 species in 12 forest patches over a year. Microclimate conditions were more similar to the forest interior in the shade-coffee matrix than in the sun-coffee matrix, but patch size and matrix type did not affect species richness and abundance in forest fragments. Furthermore, age structure and temporal recruitment patterns of the butterfly community were similar in all fragments, independent of patch size or matrix type. There were no differences in the numbers of butterflies flying in the matrices at two distances from the forest patch, but their behavior differed. Flight in the sun-coffee matrix was rapid and directional, whereas butterflies in shade-coffee matrix flew slowly. Seven out of 130 recaptured butterflies immigrated into patches in the shade-coffee matrix, and one immigrated into a patch surrounded by sun coffee. Although the shade-coffee matrix facilitated movement in the landscape, sun-coffee matrix was not impermeable to butterflies. Ithomiines exhibited behavioral plasticity in habitat use and high mobility. These traits favor their persistence in heterogeneous landscapes, opening opportunities for their conservation. Understanding the dynamics and resource requirements of different organisms in rural landscapes is critical for identifying management options that

  11. Blow Flies from Forest Fragments Embedded in Different Land Uses: Implications for Selecting Indicators in Forensic Entomology.

    PubMed

    de Souza, Mirian S; Pepinelli, Mateus; de Almeida, Eduardo C; Ochoa-Quintero, Jose M; Roque, Fabio O

    2016-01-01

    Given the general expectation that forest loss can alter biodiversity patterns, we hypothesize that blow fly species abundances differ in a gradient of native vegetation cover. This study was conducted in 17 fragments across different landscapes in central Brazil. Different land cover type proportions were used to represent landscape structure. In total, 2334 specimens of nine species of Calliphoridae were collected. We used principal component analysis (PCA) to reduce dimensionality and multicollinearity of the landscape data. The first component explained 70%, and it represented a gradient of forest-pasture land uses. Alien species showed a wide distribution in different fragments with no clear relationship between the abundance values and the scores of PCA axes, whereas native species occurred only in areas with a predominance of forest cover. Our study revealed that certain native species may be sensitive to forest loss at the landscape scale, and they represent a bioindicator in forensic entomology.

  12. Living in forest fragments reduces group cohesion in diademed sifakas (Propithecus diadema) in eastern Madagascar by reducing food patch size.

    PubMed

    Irwin, Mitchell T

    2007-04-01

    Forest fragmentation is thought to threaten primate populations, yet the mechanisms by which this occurs remain largely unknown. However, fragmentation is known to cause dietary shifts in several primate species, and links between food resource distribution and within-group spatial dynamics are well documented. Thus, fragmentation has the potential to indirectly affect spatial dynamics, and these changes may present additional stresses to fragmented populations. I present the results from a 12-month study of Propithecus diadema at Tsinjoarivo, eastern Madagascar, including two groups in fragments and two in continuous forest. Instantaneous data on activity and spatial position were collected during all-day focal animal follows. Fragment groups had much lower cohesion, being more likely to have no neighbor within 5 and 10 m. For continuous forest groups, cohesion was highest in the rainy season (when food patches are large) and lowest in winter (when the animals rely on small-crowned mistletoes), and the chance of having no neighbor within 5 m was positively correlated with mistletoe consumption. Thus their decreased cohesion in fragment groups is inferred to result from their increased reliance on mistletoes and other small resources, which causes them to spread out among multiple patches. This scenario is consistent with the reduced body mass of subordinate individuals (males and immatures) in fragments, and suggests the occurrence of steeper within-group fitness gradients. Further research is necessary to determine whether these patterns apply to other primates; however, since fragmentation tends to cause the loss of the largest trees, many primates in fragments may lose their largest food resources and undergo similar behavioral shifts.

  13. Multimodeling Framework for Predicting Water Quality in Fragmented Agriculture-Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Rose, J. B.; Guber, A.; Porter, W. F.; Williams, D.; Tamrakar, S.; Dechen Quinn, A.

    2012-12-01

    Both livestock and wildlife are major contributors of nonpoint pollution of surface water bodies. The interactions among them can substantially increase the chance of contamination especially in fragmented agriculture-forest landscapes, where wildlife (e.g. white tailed deer) can transmit diseases between remote farms. Unfortunately, models currently available for predicting fate and transport of microorganisms in these ecosystems do not account for such interactions. The objectives of this study are to develop and test a multimodeling framework that assesses the risk of microbial contamination of surface water caused by wildlife-livestock interactions in fragmented agriculture-forest ecosystems. The framework consists of a modified Soil Water Assessment Tool (SWAT), KINematic Runoff and EROSion model (KINEROS2) with the add-on module STWIR (Microorganism Transport with Infiltration and Runoff), RAMAS GIS, SIR compartmental model and Quantitative Microbial Risk Assessment model (QMRA). The watershed-scale model SWAT simulates plant biomass growth, wash-off of microorganisms from foliage and soil, overland and in-stream microbial transport, microbial growth, and die-off in foliage and soil. RAMAS GIS model predicts the most probable habitat and subsequent population of white-tailed deer based on land use and crop biomass. KINEROS-STWIR simulates overland transport of microorganisms released from soil, surface applied manure, and fecal deposits during runoff events at high temporal and special resolutions. KINEROS-STWIR and RAMAS GIS provide input for an SIR compartmental model which simulates disease transmission within and between deer groups. This information is used in SWAT model to account for transmission and deposition of pathogens by white tailed deer in stream water, foliage and soil. The QMRA approach extends to microorganisms inactivated in forage and water consumed by deer. Probabilities of deer infections and numbers of infected animals are computed

  14. Integration of ALOS/PALSAR backscatter with a LiDAR-derived canopy height map to quantify forest fragmentation

    NASA Astrophysics Data System (ADS)

    Pinto, N.; Dubayah, R.; Simard, M.; Fatoyinbo, T. E.

    2011-12-01

    Habitat loss is the main predictor of species extinctions and must be characterized in high-biodiversity ecosystems where land cover change is pervasive. Forests' ability to support viable animal populations is typically modeled as a function of the presence of linkages or corridors, and quantified with fragmentation metrics. In this scenario, small forest patches and linear (e.g. riparian) zones can act as keystone structures. Fine-resolution, all-weather Synthetic Aperture Radar (SAR) data from ALOS/PALSAR is well-suited to resolve forest fragments in tropical sites. This study summarizes a technique for integrating fragmentation metrics from ALOS/PALSAR with vertical structure data from ICESat/GLAS to produce fine-resolution (30 m) forest habitat metrics that capture both local quality (canopy height) as well as spatial context and multi-scale connectivity. We illustrate our approach with backscatter images acquired over the Brazilian Atlantic Forest, a biodiversity hotspot. ALOS/PALSAR 1.1 images acquired over the dry season were calibrated to calculate gamma naught and map forest cover via tresholding. We employ network algorithms to locate dispersal bottlenecks between conservation units. The location of keystone structures is compared against a model that uses coarse (500m) percent tree cover as an input.

  15. Assessment of organochlorine pesticide residues in Atlantic Rain Forest fragments, Rio de Janeiro, Brazil.

    PubMed

    Quinete, Natalia Soares; de Oliveira, Elba dos Santos; Fernandes, Daniella R; Avelar, Andre de Souza; Santelli, Ricardo Erthal

    2011-12-01

    A superficial water quality survey in a watershed of the Paraíba do Sul River, the main water supply for the most populated cities of southeastern Brazil, was held in order to assess the impact of the expansion of agricultural activity in the near border of the Atlantic Rain Forest. The aim of this study was to investigate the presence of priority organochlorine pollutants in soils and superficial waters of Atlantic rainforest fragments in Teresópolis, Rio de Janeiro State. Soil sample preparations were compared by using ultrasound, microwave assisted extraction and Soxhlet extraction. Recoveries of matrix spiked samples ranged from 70 to 130%. Analysis of a certified soil material showed recoveries ranging from 71 to 234%. Although low concentrations of organochlorine residues were found in water and soil samples, this area is of environmental importance and concern, thus demanding a monitoring program of its compartments.

  16. Yeast communities in two Atlantic rain Forest fragments in Southeast Brazil

    PubMed Central

    Pimenta, Raphael S.; Alves, Priscila D. D.; Almeida, Gabriel M. F.; Silva, Juliana F.M; Morais, Paula B.; Corrêa Jr., Ary; Rosa, Carlos A.

    2009-01-01

    We studied the yeast communities associated with fruits, mushrooms, tree exudates, and flies of the genus Drosophila, in two Atlantic Rain Forest fragments in state of Minas Gerais, Brazil. A total of 456 samples were collected from Rio Doce State Park and 142 from Ecological Station of Universidade Federal de Minas Gerais. From these samples, 608 yeast isolates were obtained, belonging to 71 different species. Among the yeasts isolated from Rio Doce State Park, 17 isolates were recovered from fruits, 12 from mushrooms, 13 from tree exudates, and 299 from Drosophila spp. In the Ecological Station of Universidade Federal de Minas Gerais, 24 isolates were recovered from fruits and 243 from Drosophila spp. Distinct communities of yeast were observed in Drosophila flies, fruits, mushrooms and tree exudates. The highest number of yeast species was recovered from Drosophila flies suggesting that flies are the natural vectors of these microorganisms. PMID:24031324

  17. Better Few than Hungry: Flexible Feeding Ecology of Collared Lemurs Eulemur collaris in Littoral Forest Fragments

    PubMed Central

    Donati, Giuseppe; Kesch, Kristina; Ndremifidy, Kelard; Schmidt, Stacey L.; Ramanamanjato, Jean-Baptiste; Borgognini-Tarli, Silvana M.; Ganzhorn, Joerg U.

    2011-01-01

    Background Frugivorous primates are known to encounter many problems to cope with habitat degradation, due to the fluctuating spatial and temporal distribution of their food resources. Since lemur communities evolved strategies to deal with periods of food scarcity, these primates are expected to be naturally adapted to fluctuating ecological conditions and to tolerate a certain degree of habitat changes. However, behavioral and ecological strategies adopted by frugivorous lemurs to survive in secondary habitats have been little investigated. Here, we compared the behavioral ecology of collared lemurs (Eulemur collaris) in a degraded fragment of littoral forest of south-east Madagascar, Mandena, with that of their conspecifics in a more intact habitat, Sainte Luce. Methodology/Principal Findings Lemur groups in Mandena and in Sainte Luce were censused in 2004/2007 and in 2000, respectively. Data were collected via instantaneous sampling on five lemur groups totaling 1,698 observation hours. The Shannon index was used to determine dietary diversity and nutritional analyses were conducted to assess food quality. All feeding trees were identified and measured, and ranging areas determined via the minimum convex polygon. In the degraded area lemurs were able to modify several aspects of their feeding strategies by decreasing group size and by increasing feeding time, ranging areas, and number of feeding trees. The above strategies were apparently able to counteract a clear reduction in both food quality and size of feeding trees. Conclusions/Significance Our findings indicate that collared lemurs in littoral forest fragments modified their behavior to cope with the pressures of fluctuating resource availability. The observed flexibility is likely to be an adaptation to Malagasy rainforests, which are known to undergo periods of fruit scarcity and low productivity. These results should be carefully considered when relocating lemurs or when selecting suitable areas for

  18. Spatial and Temporal Stream Temperature Response to Contemporary Forest Harvesting in the Oregon Coast Range

    NASA Astrophysics Data System (ADS)

    Bladon, K. D.; Cook, N. A.; Light, J. T.; Segura, C.; Teply, M.

    2015-12-01

    Historical research at the Alsea Watershed Study (1958-1973), in the Oregon Coast Range, demonstrated that clear-cut harvesting, with complete removal of riparian vegetation, can result in large and dramatic changes in mean daily, maximum daily, diurnal variation, and annual patterns in stream temperature (Ts). This previous research was instrumental in the addition of regulations in the Oregon Forest Practices Act of 1971, necessitating retention of streamside vegetation (riparian management zones) in harvest units to maintain water quality and aquatic habitat. Due to the ecological importance of Ts, preventing or mitigating changes in the thermal regime following land use activities, such as forest harvesting, is a primary focus of contemporary forest watershed management. The Alsea Watershed Study Revisited (2006-Present) has provided a unique opportunity to investigate the Ts responses to contemporary forest harvesting practices and compare these with the impacts from the 1960's harvest. In general, Ts increases from late spring through about mid-July, with peak Ts occuring between about mid-July and mid-August, after which Ts decreases into the fall. During the pre-harvest period (2006-2008; n=244) the June to September mean daily maximum Ts was 13.0°C in Flynn Creek (control) and 12.0°C in Needle Branch (harvested). In the post-harvest period (2010-2012; n=240) the June to September mean daily maximum Ts was 12.4°C in Flynn Creek (control) and 12.0°C in Needle Branch (harvested). Similarly, the difference (Flynn Ck - Needle Branch) in 7 day moving mean of daily maximum Ts decreased from the pre-harvest (1.0°C) to the post-harvest (0.3°C) period, which was principally driven by a decrease in Ts in the control catchment. Longitudinal sampling of Ts within Needle Branch indicated a cooling trend such that the slight increases in post-harvest Ts weren't detectable in downstream, unharvested stream reaches.

  19. Coupled nitrogen and calcium cycling in forests of the Oregon Coast Range

    USGS Publications Warehouse

    Perakis, Steven S.; Maguire, Douglas A.; Bullen, Thomas D.; Cromack, Kermit; Waring, Richard H.; Boyle, James R.

    2006-01-01

    Nitrogen (N) is a critical limiting nutrient that regulates plant productivity and the cycling of other essential elements in forests. We measured foliar and soil nutrients in 22 young Douglas-fir stands in the Oregon Coast Range to examine patterns of nutrient availability across a gradient of N-poor to N-rich soils. N in surface mineral soil ranged from 0.15 to 1.05% N, and was positively related to a doubling of foliar N across sites. Foliar N in half of the sites exceeded 1.4% N, which is considered above the threshold of N-limitation in coastal Oregon Douglas-fir. Available nitrate increased five-fold across this gradient, whereas exchangeable magnesium (Mg) and calcium (Ca) in soils declined, suggesting that nitrate leaching influences base cation availability more than soil parent material across our sites. Natural abundance strontium isotopes (87Sr/86Sr) of a single site indicated that 97% of available base cations can originate from atmospheric inputs of marine aerosols, with negligible contributions from weathering. Low annual inputs of Ca relative to Douglas-fir growth requirements may explain why foliar Ca concentrations are highly sensitive to variations in soil Ca across our sites. Natural abundance calcium isotopes (I'44Ca) in exchangeable and acid leachable pools of surface soil measured at a single site showed 1 per mil depletion relative to deep soil, suggesting strong Ca recycling to meet tree demands. Overall, the biogeochemical response of these Douglas-fir forests to gradients in soil N is similar to changes associated with chronic N deposition in more polluted temperate regions, and raises the possibility that Ca may be deficient on excessively N-rich sites. We conclude that wide gradients in soil N can drive non-linear changes in base-cation biogeochemistry, particularly as forests cross a threshold from N-limitation to N-saturation. The most acute changes may occur in forests where base cations are derived principally from atmospheric

  20. Coupled nitrogen and calcium cycles in forests of the Oregon Coast Range

    USGS Publications Warehouse

    Perakis, S.S.; Maguire, D.A.; Bullen, T.D.; Cromack, K.; Waring, R.H.; Boyle, J.R.

    2006-01-01

    Nitrogen (N) is a critical limiting nutrient that regulates plant productivity and the cycling of other essential elements in forests. We measured foliar and soil nutrients in 22 young Douglas-fir stands in the Oregon Coast Range to examine patterns of nutrient availability across a gradient of N-poor to N-rich soils. N in surface mineral soil ranged from 0.15 to 1.05% N, and was positively related to a doubling of foliar N across sites. Foliar N in half of the sites exceeded 1.4% N, which is considered above the threshold of N-limitation in coastal Oregon Douglas-fir. Available nitrate increased five-fold across this gradient, whereas exchangeable magnesium (Mg) and calcium (Ca) in soils declined, suggesting that nitrate leaching influences base cation availability more than soil parent material across our sites. Natural abundance strontium isotopes (87Sr/86Sr) of a single site indicated that 97% of available base cations can originate from atmospheric inputs of marine aerosols, with negligible contributions from weathering. Low annual inputs of Ca relative to Douglas-fir growth requirements may explain why foliar Ca concentrations are highly sensitive to variations in soil Ca across our sites. Natural abundance calcium isotopes (??44Ca) in exchangeable and acid leachable pools of surface soil measured at a single site showed 1 per mil depletion relative to deep soil, suggesting strong Ca recycling to meet tree demands. Overall, the biogeochemical response of these Douglas-fir forests to gradients in soil N is similar to changes associated with chronic N deposition in more polluted temperate regions, and raises the possibility that Ca may be deficient on excessively N-rich sites. We conclude that wide gradients in soil N can drive non-linear changes in base-cation biogeochemistry, particularly as forests cross a threshold from N-limitation to N-saturation. The most acute changes may occur in forests where base cations are derived principally from atmospheric

  1. Functional traits variation explains the distribution of Aextoxicon punctatum (Aextoxicaceae) in pronounced moisture gradients within fog-dependent forest fragments

    PubMed Central

    Salgado-Negret, Beatriz; Canessa, Rafaella; Valladares, Fernando; Armesto, Juan J.; Pérez, Fernanda

    2015-01-01

    Climate change and fragmentation are major threats to world forests. Understanding how functional traits related to drought tolerance change across small-scale, pronounced moisture gradients in fragmented forests is important to predict species’ responses to these threats. In the case of Aextoxicon punctatum, a dominant canopy tree in fog-dependent rain forest patches in semiarid Chile, we explored how the magnitude, variability and correlation patterns of leaf and xylem vessel traits and hydraulic conductivity varied across soil moisture (SM) gradients established within and among forest patches of different size, which are associated with differences in tree establishment and mortality patterns. Leaf traits varied across soil-moisture gradients produced by fog interception. Trees growing at drier leeward edges showed higher leaf mass per area, trichome and stomatal density than trees from the wetter core and windward zones. In contrast, xylem vessel traits (vessels diameter and density) did not vary producing loss of hydraulic conductivity at drier leeward edges. We also detected higher levels of phenotypic integration and variability at leeward edges. The ability of A. punctatum to modify leaf traits in response to differences in SM availability established over short distances (<500 m) facilitates its persistence in contrasting microhabitats within forest patches. However, xylem anatomy showed limited plasticity, which increases cavitation risk at leeward edges. Greater patch fragmentation, together with fluctuations in irradiance and SM in small patches, could result in higher risk of drought-related tree mortality, with profound impacts on hydrological balances at the ecosystem scale. PMID:26257746

  2. Functional traits variation explains the distribution of Aextoxicon punctatum (Aextoxicaceae) in pronounced moisture gradients within fog-dependent forest fragments.

    PubMed

    Salgado-Negret, Beatriz; Canessa, Rafaella; Valladares, Fernando; Armesto, Juan J; Pérez, Fernanda

    2015-01-01

    Climate change and fragmentation are major threats to world forests. Understanding how functional traits related to drought tolerance change across small-scale, pronounced moisture gradients in fragmented forests is important to predict species' responses to these threats. In the case of Aextoxicon punctatum, a dominant canopy tree in fog-dependent rain forest patches in semiarid Chile, we explored how the magnitude, variability and correlation patterns of leaf and xylem vessel traits and hydraulic conductivity varied across soil moisture (SM) gradients established within and among forest patches of different size, which are associated with differences in tree establishment and mortality patterns. Leaf traits varied across soil-moisture gradients produced by fog interception. Trees growing at drier leeward edges showed higher leaf mass per area, trichome and stomatal density than trees from the wetter core and windward zones. In contrast, xylem vessel traits (vessels diameter and density) did not vary producing loss of hydraulic conductivity at drier leeward edges. We also detected higher levels of phenotypic integration and variability at leeward edges. The ability of A. punctatum to modify leaf traits in response to differences in SM availability established over short distances (<500 m) facilitates its persistence in contrasting microhabitats within forest patches. However, xylem anatomy showed limited plasticity, which increases cavitation risk at leeward edges. Greater patch fragmentation, together with fluctuations in irradiance and SM in small patches, could result in higher risk of drought-related tree mortality, with profound impacts on hydrological balances at the ecosystem scale.

  3. A Framework to Predict the Impacts of Shale Gas Infrastructures on the Forest Fragmentation of an Agroforest Region

    NASA Astrophysics Data System (ADS)

    Racicot, Alexandre; Babin-Roussel, Véronique; Dauphinais, Jean-François; Joly, Jean-Sébastien; Noël, Pascal; Lavoie, Claude

    2014-05-01

    We propose a framework to facilitate the evaluation of the impacts of shale gas infrastructures (well pads, roads, and pipelines) on land cover features, especially with regards to forest fragmentation. We used a geographic information system and realistic development scenarios largely inspired by the PA (United States) experience, but adapted to a region of QC (Canada) with an already fragmented forest cover and a high gas potential. The scenario with the greatest impact results from development limited by regulatory constraints only, with no access to private roads for connecting well pads to the public road network. The scenario with the lowest impact additionally integrates ecological constraints (deer yards, maple woodlots, and wetlands). Overall the differences between these two scenarios are relatively minor, with <1 % of the forest cover lost in each case. However, large areas of core forests would be lost in both scenarios and the number of forest patches would increase by 13-21 % due to fragmentation. The pipeline network would have a much greater footprint on the land cover than access roads. Using data acquired since the beginning of the shale gas industry, we show that it is possible, within a reasonable time frame, to produce a robust assessment of the impacts of shale gas extraction. The framework we propose could easily be applied to other contexts or jurisdictions.

  4. Deagrarianisation and Forest Revegetation in a Biodiversity Hotspot on the Wild Coast, South Africa

    PubMed Central

    Shackleton, Ross; Shackleton, Charlie; Shackleton, Sheona; Gambiza, James

    2013-01-01

    Deagraianisation is a worldwide phenomenon with widespread social, ecological and economic effects yet with little consensus on the local or higher level causes. There have been contested views on the causes and consequences of deagrarianisation on South Africa’s Wild Coast, which is an international biodiversity hotspot. Using GIS, household interviews and ecological sampling, we compared the perspectives of current and former cultivators as to why some have abandoned farming, whilst also tracking the uses and woody plant cover and composition of fields abandoned at different periods. The GIS analysis showed that field abandonment had been ongoing over several decades, with a decline from 12.5 % field cover in 1961 to 2.7 % in 2009. The area of forests and woodlands almost doubled in the corresponding period. There was a distinct peak in field abandonment during the time of political transition at the national level in the early 1990s. This political change led to a decrease in government support for livestock farming, which in turn resulted in reduced animal draught power at the household and community level, and hence reduced cropping. The study showed it is largely the wealthier households that have remained in arable agriculture and that the poorer households have abandoned farming. The abandoned fields show a distinct trend of increasing woody biomass and species richness with length of time since abandonment, with approximately three woody plant species added per decade. Most local respondents dislike the increases in forest and woodland extent and density because of anxiety about wild animals causing harm to crops and even humans, and the loss of an agricultural identity to livelihoods and the landscape. PMID:24155911

  5. Deagrarianisation and forest revegetation in a biodiversity hotspot on the Wild Coast, South Africa.

    PubMed

    Shackleton, Ross; Shackleton, Charlie; Shackleton, Sheona; Gambiza, James

    2013-01-01

    Deagraianisation is a worldwide phenomenon with widespread social, ecological and economic effects yet with little consensus on the local or higher level causes. There have been contested views on the causes and consequences of deagrarianisation on South Africa's Wild Coast, which is an international biodiversity hotspot. Using GIS, household interviews and ecological sampling, we compared the perspectives of current and former cultivators as to why some have abandoned farming, whilst also tracking the uses and woody plant cover and composition of fields abandoned at different periods. The GIS analysis showed that field abandonment had been ongoing over several decades, with a decline from 12.5 % field cover in 1961 to 2.7 % in 2009. The area of forests and woodlands almost doubled in the corresponding period. There was a distinct peak in field abandonment during the time of political transition at the national level in the early 1990s. This political change led to a decrease in government support for livestock farming, which in turn resulted in reduced animal draught power at the household and community level, and hence reduced cropping. The study showed it is largely the wealthier households that have remained in arable agriculture and that the poorer households have abandoned farming. The abandoned fields show a distinct trend of increasing woody biomass and species richness with length of time since abandonment, with approximately three woody plant species added per decade. Most local respondents dislike the increases in forest and woodland extent and density because of anxiety about wild animals causing harm to crops and even humans, and the loss of an agricultural identity to livelihoods and the landscape.

  6. Deagrarianisation and forest revegetation in a biodiversity hotspot on the Wild Coast, South Africa.

    PubMed

    Shackleton, Ross; Shackleton, Charlie; Shackleton, Sheona; Gambiza, James

    2014-01-01

    Deagraianisation is a worldwide phenomenon with widespread social, ecological and economic effects yet with little consensus on the local or higher level causes. There have been contested views on the causes and consequences of deagrarianisation on South Africa's Wild Coast, which is an international biodiversity hotspot. Using GIS, household interviews and ecological sampling, we compared the perspectives of current and former cultivators as to why some have abandoned farming, whilst also tracking the uses and woody plant cover and composition of fields abandoned at different periods. The GIS analysis showed that field abandonment had been ongoing over several decades, with a decline from 12.5 % field cover in 1961 to 2.7 % in 2009. The area of forests and woodlands almost doubled in the corresponding period. There was a distinct peak in field abandonment during the time of political transition at the national level in the early 1990 s. This political change led to a decrease in government support for livestock farming, which in turn resulted in reduced animal draught power at the household and community level, and hence reduced cropping. The study showed it is largely the wealthier households that have remained in arable agriculture and that the poorer households have abandoned farming. The abandoned fields show a distinct trend of increasing woody biomass and species richness with length of time since abandonment, with approximately three woody plant species added per decade. Most local respondents dislike the increases in forest and woodland extent and density because of anxiety about wild animals causing harm to crops and even humans, and the loss of an agricultural identity to livelihoods and the landscape.

  7. Role of storms and forest practices in sedimentation of an Oregon Coast Range lake

    NASA Astrophysics Data System (ADS)

    Richardson, K.; Hatten, J. A.; Wheatcroft, R. A.; Guerrero, F. J.

    2014-12-01

    The design of better management practices in forested watersheds to face climate change and the associated increase in the frequency of extreme events requires a better understanding of watershed responses to extreme events in the past and also under management regimes. One of the most sensitive watershed processes affected is sediment yield. Lake sediments record events which occur in a watershed and provide an opportunity to examine the interaction of storms and forest management practices in the layers of the stratigraphy. We hypothesize that timber harvesting and road building since the 1900s has resulted in increases in sedimentation; however, the passage of the Oregon Forest Practices Act (OFPA) in 1972 has led to a decrease in sedimentation. Sediment cores were taken at Loon Lake in the Oregon Coast Range. The 32-m deep lake captures sediment from a catchment highly impacted by recent land use and episodic Pacific storms. We can use sedimentological tools to measure changes in sediment production as motivated by extreme floods before settlement, during a major timber harvesting period, and after installation of forestry Best Management Practices. Quantification of changes in particle size and elemental composition (C, N, C/N) throughout the cores can elucidate changes in watershed response to extreme events, as can changes in layer thickness. Age control in the cores is being established by Cesium-137 and radiocarbon dating. Given the instrumental meteorological data and decadal climate reconstructions, we will disentangle climate driven signals from changes in land use practices. The sediment shows distinct laminations and varying thickness of layers throughout the cores. Background deposition is composed of thin layers (<0.5 cm) of fine silts and clays, punctuated by thicker layers (3-25 cm) every 10 to 75 cm. These thick layers consist of distinctly textured units, generally fining upward. We interpret the thick layers in Loon Lake to be deposited by

  8. Low functional richness and redundancy of a predator assemblage in native forest fragments of Chiloe island, Chile.

    PubMed

    Farias, Ariel A; Jaksic, Fabian M

    2011-07-01

    1. Changes in land use and habitat fragmentation are major drivers of global change, and studying their effects on biodiversity constitutes a major research programme. However, biodiversity is a multifaceted concept, with a functional component linking species richness to ecosystem function. Currently, the interaction between functional and taxonomic components of biodiversity under realistic scenarios of habitat degradation is poorly understood. 2. The expected functional richness (FR)-species richness relationship (FRSR) is positive, and attenuated for functional redundancy in species-rich assemblages. Further, environmental filters are expected to flatten that association by sorting species with similar traits. Thus, analysing FRSR can inform about the response of biodiversity to environmental gradients and habitat fragmentation, and its expected functional consequences. 3. Top predators affect ecosystem functioning through prey consumption and are particularly vulnerable to changes in land use and habitat fragmentation, being good indicators of ecosystem health and suitable models for assessing the effects of habitat fragmentation on their FR. 4. Thus, this study analyses the functional redundancy of a vertebrate predator assemblage at temperate forest fragments in a rural landscape of Chiloe island (Chile), testing the existence of environmental filters by contrasting an empirically derived FRSR against those predicted from null models, and testing the association between biodiversity components and the structure of forest fragments. 5. Overall, contrasts against null models indicate that regional factors determine low levels of FR and redundancy for the vertebrate predator assemblage studied, while recorded linear FRSR indicates proportional responses of the two biodiversity components to the structure of forest fragments. Further, most species were positively associated with either fragment size or shape complexity, which are highly correlated. This, and the

  9. Implications of Fine-Grained Habitat Fragmentation and Road Mortality for Jaguar Conservation in the Atlantic Forest, Brazil.

    PubMed

    Cullen, Laury; Stanton, Jessica C; Lima, Fernando; Uezu, Alexandre; Perilli, Miriam L L; Akçakaya, H Reşit

    2016-01-01

    Jaguar (Panthera onca) populations in the Upper Paraná River, in the Brazilian Atlantic Forest region, live in a landscape that includes highly fragmented areas as well as relatively intact ones. We developed a model of jaguar habitat suitability in this region, and based on this habitat model, we developed a spatially structured metapopulation model of the jaguar populations in this area to analyze their viability, the potential impact of road mortality on the populations' persistence, and the interaction between road mortality and habitat fragmentation. In more highly fragmented populations, density of jaguars per unit area is lower and density of roads per jaguar is higher. The populations with the most fragmented habitat were predicted to have much lower persistence in the next 100 years when the model included no dispersal, indicating that the persistence of these populations are dependent to a large extent on dispersal from other populations. This, in turn, indicates that the interaction between road mortality and habitat fragmentation may lead to source-sink dynamics, whereby populations with highly fragmented habitat are maintained only by dispersal from populations with less fragmented habitat. This study demonstrates the utility of linking habitat and demographic models in assessing impacts on species living in fragmented landscapes.

  10. Implications of Fine-Grained Habitat Fragmentation and Road Mortality for Jaguar Conservation in the Atlantic Forest, Brazil

    PubMed Central

    Cullen, Laury; Stanton, Jessica C.; Lima, Fernando; Uezu, Alexandre; Perilli, Miriam L. L.; Akçakaya, H. Reşit

    2016-01-01

    Jaguar (Panthera onca) populations in the Upper Paraná River, in the Brazilian Atlantic Forest region, live in a landscape that includes highly fragmented areas as well as relatively intact ones. We developed a model of jaguar habitat suitability in this region, and based on this habitat model, we developed a spatially structured metapopulation model of the jaguar populations in this area to analyze their viability, the potential impact of road mortality on the populations' persistence, and the interaction between road mortality and habitat fragmentation. In more highly fragmented populations, density of jaguars per unit area is lower and density of roads per jaguar is higher. The populations with the most fragmented habitat were predicted to have much lower persistence in the next 100 years when the model included no dispersal, indicating that the persistence of these populations are dependent to a large extent on dispersal from other populations. This, in turn, indicates that the interaction between road mortality and habitat fragmentation may lead to source-sink dynamics, whereby populations with highly fragmented habitat are maintained only by dispersal from populations with less fragmented habitat. This study demonstrates the utility of linking habitat and demographic models in assessing impacts on species living in fragmented landscapes. PMID:27973584

  11. Quantifying habitat requirements of tree-living species in fragmented boreal forests with Bayesian methods.

    PubMed

    Berglund, Håkan; O'Hara, Robert B; Jonsson, Bengt Gunnar

    2009-10-01

    Quantitative conservation objectives require detailed consideration of the habitat requirements of target species. Tree-living bryophytes, lichens, and fungi are a critical and declining biodiversity component of boreal forests. To understand their requirements, Bayesian methods were used to analyze the relationships between the occurrence of individual species and habitat factors at the tree and the stand scale in a naturally fragmented boreal forest landscape. The importance of unexplained between-stand variation in occurrence of species was estimated, and the ability of derived models to predict species' occurrence was tested. The occurrence of species was affected by quality of individual trees. Furthermore, the relationships between occurrence of species at the tree level and size and shape of stands indicated edge effects, implying that some species were restricted to interior habitats of large, regular stands. Yet for the habitat factors studied, requirements of many species appeared similar. Species occurrence also varied between stands; most of the seemingly suitable trees in some stands were unoccupied. The models captured most variation in species occurrence at tree level. They also successfully accounted for between-stand variation in species occurrence, thus providing realistic simulations of stand-level occupancy of species. Important unexplained between-stand variation in species occurrence warns against a simplified view that only local habitat factors influence species' occurrence. Apparently, similar stands will host populations of different sizes due to historical, spatial, and stochastic factors. Thus, habitat suitability cannot be assessed simply by population sizes, and stands lacking a species may still provide suitable habitat and merit protection.

  12. Hurricane Mitch: Landscape Analysis of Damaged Forest Resources of the Bay Islands and Caribbean Coast of Honduras

    USGS Publications Warehouse

    Doyle, Thomas W.; Michot, Thomas C.; Roetker, Fred; Sullivan, Jason; Melder, Marcus; Handley, Benjamin; Balmat, Jeff

    2002-01-01

    The advent of analog and digital video has provided amateur photographers with professional-like technology to capture dynamic images with ease and clarity. Videography is also rapidly changing traditional business and scientific applications. In the natural sciences, camcorders are being used largely to record timely observations of plant and animal behavior or consequence of some catastrophic event. Spectacular video of dynamic events such as hurricanes, volcanic eruptions and wildfire document the active process and aftermath. Scientists can analyze video images to quantify aspects of a given event, behavior, or response, temporally and spatially. In this study we demonstrate the simple use of an aerial application of videography to record the spatial extent and damage expression of mangrove forest in the Bay Islands and mainland coast of northern Honduras from wind damage following Hurricane Mitch (1998). In this study, we conducted a video overflight of coastal forests of the Bay Islands and mainland coast of northern Honduras 14 months after impact by Hurricane Mitch (1998). Coastal areas were identified where damage was evident and described relative to damage extent to forest cover, windfall orientation, and height of downed trees. The variability and spatial extent of impact on coastal forest resources is related to reconstructed wind profiles based on model simulations of Mitch's path, strength, and circulation during landfall.

  13. Forest fire ash impact on micro- and macroalgae in the receiving waters of the east coast of South Korea.

    PubMed

    Shin, Hyun-Woung; Sidharthan, M; Young, Kim Shin

    2002-01-01

    Mountain forest fire ash flushed into the eastern coastal waters of South Korea is known to contain cadmium as one of its significant constituents. To study its impact, two representatives of the micro- and macroalgal communities, Ulva pertusa and Nannochloropsis oculata, were exposed to the concentration range of Cd indicated from the forest fire localities. At low concentrations of 0.224-0.448 mg L(-1), a 20% reduction in growth rate of N. oculata was observed. Chlorophyll a pigment concentration was proportionate to the growth reduction while at higher concentrations (1.792 mg L(-1)) pigments were completely leached. In the macrophyte U. pertusa, a similar trend of pigment leaching was observed. Bioaccumulation factors obtained for these rapidly growing algal species revealed excessive bioconcentration of Cd. Variations in the concentration of Cd among the samples collected along the Korean coast clearly indicated the additional source of metal influx from the forest fires.

  14. Mechanisms Driving Galling Success in a Fragmented Landscape: Synergy of Habitat and Top-Down Factors along Temperate Forest Edges.

    PubMed

    Kelch, Nina-S; Neves, Frederico S; Fernandes, G Wilson; Wirth, Rainer

    2016-01-01

    Edge effects play key roles in the anthropogenic transformation of forested ecosystems and their biota, and are therefore a prime field of contemporary fragmentation research. We present the first empirical study to address edge effects on the population level of a widespread galling herbivore in a temperate deciduous forest. By analyzing edge effects on abundance and trophic interactions of beech gall midge (Mikiola fagi Htg.), we found 30% higher gall abundance in the edge habitat as well as lower mortality rates due to decreased top-down control, especially by parasitoids. Two GLM models with similar explanatory power (58%) identified habitat specific traits (such as canopy closure and altitude) and parasitism as the best predictors of gall abundance. Further analyses revealed a crucial influence of light exposure (46%) on top-down control by the parasitoid complex. Guided by a conceptual framework synthesizing the key factors driving gall density, we conclude that forest edge proliferation of M. fagi is due to a complex interplay of abiotic changes and trophic control mechanisms. Most prominently, it is caused by the microclimatic regime in forest edges, acting alone or in synergistic concert with top-down pressure by parasitoids. Contrary to the prevailing notion that specialists are edge-sensitive, this turns M. fagi into a winner species in fragmented temperate beech forests. In view of the increasing proportion of edge habitats and the documented benefits from edge microclimate, we call for investigations exploring the pest status of this galling insect and the modulators of its biological control.

  15. Domestic dogs in a fragmented landscape in the Brazilian Atlantic Forest: abundance, habitat use and caring by owners.

    PubMed

    Torres, P C; Prado, P I

    2010-11-01

    This study aimed at estimating the population size and attitudes of residents towards caring for domestic dogs, through questionnaire surveys, as well as the frequency of these animals in different habitats (anthropic and forest patch), using scent stations. The study was conducted in a severely fragmented area of the Brazilian Atlantic Forest. A large number of unrestricted dogs was recorded, averaging 6.2 ind/km². These dogs have owners and are regularly fed. Dog records decreased from the anthropogenic matrix to the forest patch edge, which suggests that dogs act as an edge effect on forest patches. Encounters between domestic dog and wild animals can still be frequent in severely fragmented landscapes, mainly at the forest edges. However the fact that most dogs have an owner and are more frequent in the anthropic habitat suggests that their putative effects are less severe than expected for a carnivore of such abundance, but the reinforcement of responsible ownership is needed to further ameliorate such effects.

  16. Feather mites (Acari, Astigmata) associated with birds in an Atlantic Forest fragment in Northeastern Brazil.

    PubMed

    Silva, H M; Hernandes, F A; Pichorim, M

    2015-08-01

    The present study reports associations between feather mites (Astigmata) and birds in an Atlantic Forest fragment in Rio Grande do Norte state, in Brazil. In the laboratory, mites were collected through visual examination of freshly killed birds. Overall, 172 individuals from 38 bird species were examined, between October 2011 and July 2012. The prevalence of feather mites was 80.8%, corresponding to 139 infested individuals distributed into 30 species and 15 families of hosts. Fifteen feather mite taxa could be identified to the species level, sixteen to the genus level and three to the subfamily level, distributed into the families Analgidae, Proctophyllodidae, Psoroptoididae, Pteronyssidae, Xolalgidae, Trouessartiidae, Falculiferidae and Gabuciniidae. Hitherto unknown associations between feather mites and birds were recorded for eleven taxa identified to the species level, and nine taxa were recorded for the first time in Brazil. The number of new geographic records, as well as the hitherto unknown mite-host associations, supports the high estimates of diversity for feather mites of Brazil and show the need for research to increase knowledge of plumicole mites in the Neotropical region.

  17. Effects of forest fragmentation on the seedling recruitment of a tropical herb: assessing seed vs. safe-site limitation.

    PubMed

    Uriarte, María; Bruna, Emilio M; Rubim, Paulo; Anciães, Marina; Jonckheere, Inge

    2010-05-01

    Studies simultaneously evaluating the importance of safe-site and seed limitation for plant establishment are rare, particularly in human-modified landscapes. We used spatially explicit neighborhood models together with data from 10 0.5-ha mapped census plots in a fragmented landscape spanning 1000 km2 to (1) evaluate the relative importance of seed production, dispersal, and safe-site limitation for the recruitment of the understory herb Heliconia acuminata; and (2) determine how these processes differ between fragments and continuous forests. Our analyses demonstrated a large degree of variation in seed production, dispersal, and establishment among and within the 10 study plots. Seed production limitation was strong but only at small spatial scales. Average dispersal distance was less than 4 m, leading to severe dispersal limitation at most sites. Overall, safe-site limitation was the most important constraint on seedling establishment. Fragmentation led to a more heterogeneous light environment with negative consequences for seedling establishment but had little effect on seed production or dispersal. These results suggest that the effects of fragmentation on abiotic processes may be more important than the disruption of biotic interactions in driving biodiversity loss in tropical forests, at least for some functional groups. These effects may be common when the matrix surrounding fragments contains enough tree cover to enable movement of dispersers and pollinators.

  18. Dynamic anthropogenic edge effects on the distribution and diversity of fungi in fragmented old-growth forests.

    PubMed

    Ruete, Alejandro; Snäll, Tord; Jönsson, Mari

    2016-07-01

    Diversity patterns and dynamics at forest edges are not well understood. We disentangle the relative importance of edge-effect variables on spatio-temporal patterns in species richness and occupancy of deadwood-dwelling fungi in fragmented old-growth forests. We related richness and log occupancy by 10 old-growth forest indicator fungi and by two common fungi to log conditions in natural and anthropogenic edge habitats of 31 old-growth Picea abies forest stands in central Sweden. We compared edge-to-interior gradients (100 m) to the forest interior (beyond 100 m), and we analyzed stand-level changes after 10 yr. Both richness and occupancy of logs by indicator species was negatively related to adjacent young clear-cut edges, but this effect decreased with increasing clear-cut age. The occupancy of logs by indicator species also increased with increasing distance to the natural edges. In contrast, the occupancy of logs by common species was positively related or unrelated to distance to clear-cut edges regardless of the edge age, and this was partly explained by fungal specificity to substrate quality. Stand-level mean richness and mean occupancy of logs did not change for indicator or common species over a decade. By illustrating the importance of spatial and temporal dimensions of edge effects, we extend the general understanding of the distribution and diversity of substrate-confined fungi in fragmented old-growth forests. Our results highlight the importance of longer forest rotation times adjacent to small protected areas and forest set-asides, where it may take more than 50 yr for indicator species richness levels to recover to occupancy levels observed in the forest interior. Also, non-simultaneous clear-cutting of surrounding productive forests in a way that reduces the edge effect over time (i.e., dynamic buffers) may increase the effective core area of small forest set-asides and improve their performance on protecting species of special concern for

  19. Change and fragmentation trends of Zhanjiang mangrove forests in southern China using multi-temporal Landsat imagery (1977-2010)

    NASA Astrophysics Data System (ADS)

    Li, M. S.; Mao, L. J.; Shen, W. J.; Liu, S. Q.; Wei, A. S.

    2013-09-01

    Mangrove forests, which are found in saline coastal environments around the tropical and subtropical latitudes, are among the most productive terrestrial ecosystems in the world and provide valuable ecological and societal goods and services. The objective of this work was to characterize the spatio-temporal changes in mangrove distribution and fragmentation patterns in the Zhanjiang National Mangrove Forest Nature Reserve, Guangdong province of Southern China, from 1977 through 2010. In addition, a major goal was to assess the socio-economic drivers contributing to the chronic changes taking place within and around the mangrove reserve. Land use and land cover data sets were generated for the reserve for multiple years via unsupervised classification using Landsat time series images. Mangrove fragmentation patterns were then assessed with a fragmentation model. Results revealed that the mangrove spatial extent decreased sharply during the period from 1977 to 1991 due to deforestation caused by diverse development programs, particularly shrimp farming. Afterwards, there was a continuous increase in mangrove extent from 1991 to 2010 due to afforestation and conservation efforts. The mangrove fragmentation trends depicted by the fragmentation model had a high degree of correlation with the observed areal changes. Additionally, the recorded dynamics of the local biodiversity (mainly birds) were consistent with the mangrove ecosystem fragmentation trends over time, and different fragmentation components, including interior, perforated and edge, had distinct impacts on the local mangrove-dependent biodiversity. The most effective way to protect and expand the current mangroves include the following: (1) establishment of mangrove natural reserves, (2) forceful implementation of regulations, (3) establishment of educational programs related to mangrove management, (4) deepening international exchanges and cooperation and (5) increasing the transparency of the project

  20. Snake richness in urban forest fragments from Niterói and surroundings, state of Rio de Janeiro, southeastern Brazil

    PubMed Central

    Citeli, Nathalie; Hamdan, Breno

    2016-01-01

    Abstract Background The Atlantic Forest is a hotspot for biodiversity, an area which houses high species richness and endemism, but with high level of threat. With reference to the herpetofauna, until recently there has been no detailed information regarding diversity of snakes recorded in the Atlantic Forest, the number of endemic species and their distribution ranges. While these basic data were missing, large areas of original forest have continued to be lost to increased urbanization and human population, representing a severe threat to the biodiversity. New information We recorded 28 snake species in our study area. Dipsadidae was the richest family with 14 species, followed by Colubridae (eight species), Boidae (two species), Viperidae (two species), and Anomalepididae, Elapidae and Typhlopidae (one species each). Most species were forest inhabitants (61%), of which 13 are endemic to the Atlantic Forest. There were no clearly defined species clusters regarding species composition. None of the species recorded in Niterói are listed as threatened in the Brazilian Redlist. However, most of them are strongly associated with forested areas and, perhaps, are not adapted to live in small fragments. Thus, more initiatives should be implemented to evaluate the true conservation status of these species in order to better protect them. PMID:26929711

  1. Bat-Fruit Interactions Are More Specialized in Shaded-Coffee Plantations than in Tropical Mountain Cloud Forest Fragments

    PubMed Central

    Hernández-Montero, Jesús R.; Saldaña-Vázquez, Romeo A.; Galindo-González, Jorge; Sosa, Vinicio J.

    2015-01-01

    Forest disturbance causes specialization of plant-frugivore networks and jeopardizes mutualistic interactions through reduction of ecological redundancy. To evaluate how simplification of a forest into an agroecosystem affects plant-disperser mutualistic interactions, we compared bat-fruit interaction indexes of specialization in tropical montane cloud forest fragments (TMCF) and shaded-coffee plantations (SCP). Bat-fruit interactions were surveyed by collection of bat fecal samples. Bat-fruit interactions were more specialized in SCP (mean H2 ' = 0.55) compared to TMCF fragments (mean H2 ' = 0.27), and were negatively correlated to bat abundance in SCP (R = -0.35). The number of shared plant species was higher in the TMCF fragments (mean = 1) compared to the SCP (mean = 0.51) and this was positively correlated to the abundance of frugivorous bats (R= 0.79). The higher specialization in SCP could be explained by lower bat abundance and lower diet overlap among bats. Coffee farmers and conservation policy makers must increase the proportion of land assigned to TMCF within agroecosystem landscapes in order to conserve frugivorous bats and their invaluable seed dispersal service. PMID:25992550

  2. Bat-fruit interactions are more specialized in shaded-coffee plantations than in tropical mountain cloud forest fragments.

    PubMed

    Hernández-Montero, Jesús R; Saldaña-Vázquez, Romeo A; Galindo-González, Jorge; Sosa, Vinicio J

    2015-01-01

    Forest disturbance causes specialization of plant-frugivore networks and jeopardizes mutualistic interactions through reduction of ecological redundancy. To evaluate how simplification of a forest into an agroecosystem affects plant-disperser mutualistic interactions, we compared bat-fruit interaction indexes of specialization in tropical montane cloud forest fragments (TMCF) and shaded-coffee plantations (SCP). Bat-fruit interactions were surveyed by collection of bat fecal samples. Bat-fruit interactions were more specialized in SCP (mean H2 ' = 0.55) compared to TMCF fragments (mean H2 ' = 0.27), and were negatively correlated to bat abundance in SCP (R = -0.35). The number of shared plant species was higher in the TMCF fragments (mean = 1) compared to the SCP (mean = 0.51) and this was positively correlated to the abundance of frugivorous bats (R= 0.79). The higher specialization in SCP could be explained by lower bat abundance and lower diet overlap among bats. Coffee farmers and conservation policy makers must increase the proportion of land assigned to TMCF within agroecosystem landscapes in order to conserve frugivorous bats and their invaluable seed dispersal service.

  3. Population density, sex ratio, body size and fluctuating asymmetry of Ceroglossus chilensis (Carabidae) in the fragmented Maulino forest and surrounding pine plantations

    NASA Astrophysics Data System (ADS)

    Henríquez, Paula; Donoso, Denise S.; Grez, Audrey A.

    2009-11-01

    Habitat fragmentation results in new environmental conditions that may stress resident populations. Such stress may be reflected in demographical or morphological changes in the individuals inhabiting those landscapes. This study evaluates the effects of fragmentation of the Maulino forest on population density, sex ratio, body size, and fluctuating asymmetry (FA) of the endemic carabid Ceroglossus chilensis. Individuals of C. chilensis were collected during 2006 in five locations at Los Queules National Reserve (continuous forest), in five forest fragments and in five areas of surrounding pine plantations (matrix). In each location, once a season, 40 pitfall traps (20 in the centre, 20 in the edge), were opened for 72 h. Population density of C. chilensis was higher in the small fragments than in the pine matrix, with intermediate densities in the continuous forest; sex ratio did not differ significantly from 1:1 in the three habitats. Individuals from the centre of fragments were smaller than those from the centre of continuous forest, and FA did not vary significantly among habitats. These results suggest that small forest fragments maintain dense populations of C. chilensis and therefore they must be considered in conservation strategies. Although the decrease of the body size suggests that small remnants should be connected by managing the structure of the surrounding matrix, facilitating the dispersion of this carabid across the landscape and avoiding possible antagonistic interactions inside small fragments.

  4. Habitat fragmentation and haemoparasites in the common fruit bat, Artibeus jamaicensis (Phyllostomidae) in a tropical lowland forest in Panamá.

    PubMed

    Cottontail, V M; Wellinghausen, N; Kalko, E K V

    2009-09-01

    Anthropogenic influence on ecosystems, such as habitat fragmentation, impacts species diversity and interactions. There is growing evidence that degradation of habitats favours disease and hence affects ecosystem health. The prevalence of haemoparasites in the Common Fruit Bat (Artibeus jamaicensis) in a tropical lowland forest in Panamá was studied. We assessed the relation of haemoparasite to the general condition of the animals and tested for possible association of haemoparasite prevalence to habitat fragmentation, with special focus on trypanosomes. Overall, a total of 250 A. jamaicensis sampled from fragmented sites, here man-made, forested islands in Lake Gatùn, and sites in the adjacent, continuous forest in and around the Barro Colorado Nature Monument were examined. Using microscopy and DNA-sequencing 2 dominant types of haemoparasite infections, trypanosomes and Litomosoides (Nematoda) were identified. Trypanosome prevalence was significantly higher in bats from forest fragments, than in bats captured in continuous forest. We attribute this to the loss of species richness in forest fragments and specific characteristics of the fragments favouring trypanosome transmission, in particular changes in vegetation cover. Interestingly, the effect of habitat fragmentation on the prevalence of trypanosomes as multi-host parasites could not be observed in Litomosoides which probably has a higher host specificity and might be affected less by overall diversity loss.

  5. Edge-interior differences in the species richness and abundance of drosophilids in a semideciduous forest fragment.

    PubMed

    Penariol, Leiza V; Madi-Ravazzi, Lilian

    2013-12-01

    Habitat fragmentation is the main cause of biodiversity loss, as remnant fragments are exposed to negative influences that include edge effects, prevention of migration, declines in effective population sizes, loss of genetic variability and invasion of exotic species. The Drosophilidae (Diptera), especially species of the genus Drosophila, which are highly sensitive to environmental variation, have been used as bioindicators. A twelve-month field study was conducted to evaluate the abundance and richness of drosophilids in an edge-interior transect in a fragment of semideciduous forest in São Paulo State, Brazil. One objective of the study was to evaluate the applied methodology with respect to its potential use in future studies addressing the monitoring and conservation of threatened areas. The species abundance along the transect showed a clear gradient, with species associated with disturbed environments, such as Drosophila simulans, Scaptodrosophila latifasciaeformis and Zaprionus indianus, being collected at the fragment edge and the species D. willistoni and D. mediostriata being found in the fragment's interior. Replacement of these species occurred at approximately 60 meters from the edge, which may be a reflection of edge effects on species abundance and richness because the species found within the habitat fragment are more sensitive to variations in temperature and humidity than those sampled near the edge. The results support the use of this methodology in studies on environmental impacts.

  6. Increased autumn rainfall disrupts predator-prey interactions in fragmented boreal forests.

    PubMed

    Terraube, Julien; Villers, Alexandre; Poudré, Léo; Varjonen, Rauno; Korpimäki, Erkki

    2016-07-02

    There is a pressing need to understand how changing climate interacts with land-use change to affect predator-prey interactions in fragmented landscapes. This is particularly true in boreal ecosystems facing fast climate change and intensification in forestry practices. Here, we investigated the relative influence of autumn climate and habitat quality on the food-storing behaviour of a generalist predator, the pygmy owl, using a unique data set of 15 850 prey items recorded in western Finland over 12 years. Our results highlighted strong effects of autumn climate (number of days with rainfall and with temperature <0 °C) on food-store composition. Increasing frequency of days with precipitation in autumn triggered a decrease in (i) total prey biomass stored, (ii) the number of bank voles (main prey) stored, and (iii) the scaled mass index of pygmy owls. Increasing proportions of old spruce forests strengthened the functional response of owls to variations in vole abundance and were more prone to switch from main prey to alternative prey (passerine birds) depending on local climate conditions. High-quality habitat may allow pygmy owls to buffer negative effects of inclement weather and cyclic variation in vole abundance. Additionally, our results evidenced sex-specific trends in body condition, as the scaled mass index of smaller males increased while the scaled mass index of larger females decreased over the study period, probably due to sex-specific foraging strategies and energy requirements. Long-term temporal stability in local vole abundance refutes the hypothesis of climate-driven change in vole abundance and suggests that rainier autumns could reduce the vulnerability of small mammals to predation by pygmy owls. As small rodents are key prey species for many predators in northern ecosystems, our findings raise concern about the impact of global change on boreal food webs through changes in main prey vulnerability.

  7. EFFECTS OF HYDROGEOMORPHIC REGION, WATERSHED STORAGE, AND FOREST FRAGMENTATION ON WATERSHED EXPORTS

    EPA Science Inventory

    Turbidity was highest for South Shore streams overall, but exhibited a significant HGM x storage x fragmentation effect, with highest levels observed in South Shore low storage/high fragmentation watersheds.

  8. Effects of logging, hunting, and forest fragment size on physiological stress levels of two sympatric ateline primates in Colombia

    PubMed Central

    Rimbach, Rebecca; Link, Andrés; Heistermann, Michael; Gómez-Posada, Carolina; Galvis, Nelson; Heymann, Eckhard W.

    2013-01-01

    Habitat fragmentation and anthropogenic disturbances are of major concern to the conservation of endangered species because of their potentially negative impact on animal populations. Both processes can impose physiological stress (i.e. increased glucocorticoid output) on animals, and chronically elevated stress levels can have detrimental effects on the long-term viability of animal populations. Here, we investigated the effect of fragment size and human impact (logging and hunting pressure) on glucocorticoid levels of two sympatric Neotropical primates, the red howler monkey (Alouatta seniculus) and the critically endangered brown spider monkey (Ateles hybridus). These two species have been reported to contrast strongly in their ability to cope with anthropogenic disturbances. We collected faecal samples from eight spider monkey groups and 31 howler monkey groups, living in seven and 10 different forest fragments in Colombia, respectively. We measured faecal glucocorticoid metabolite (FGCM) levels in both species using previously validated methods. Surprisingly, fragment size did not influence FGCM levels in either species. Spider monkeys showed elevated FGCMs in fragments with the highest level of human impact, whereas we did not find this effect in howler monkeys. This suggests that the two species differ in their physiological responsiveness to anthropogenic changes, further emphasizing why brown spider monkeys are at higher extinction risk than red howler monkeys. If these anthropogenic disturbances persist in the long term, elevated FGCM levels can potentially lead to a state of chronic stress, which might limit the future viability of populations. We propose that FGCM measurements should be used as a tool to monitor populations living in disturbed areas and to assess the success of conservation strategies, such as corridors connecting forest fragments. PMID:27293615

  9. Temporal Changes in Forest Contexts at Multiple Extents: Three Decades of Fragmentation in the Gran Chaco (1979-2010), Central Argentina.

    PubMed

    Frate, Ludovico; Acosta, Alicia T R; Cabido, Marcelo; Hoyos, Laura; Carranza, Maria Laura

    2015-01-01

    The context in which a forest exists strongly influences its function and sustainability. Unveiling the multi-scale nature of forest fragmentation context is crucial to understand how human activities affect the spatial patterns of forests across a range of scales. However, this issue remains almost unexplored in subtropical ecosystems. In this study, we analyzed temporal changes (1979-2010) in forest contexts in the Argentinean dry Chaco at multiple extents. We classified forests over the last three decades based on forest context amount (Pf) and structural connectivity (Pff), which were measured using a moving window approach fixed at eight different extents (from local, ~ 6 ha, to regional, ~ 8300 ha). Specific multi-scale forest context profiles (for the years 1979 and 2010) were defined by projecting Pf vs. Pff mean values and were compared across spatial extents. The distributions of Pf across scales were described by scalograms and their shapes over time were compared. The amount of agricultural land and rangelands across the scales were also analyzed. The dry Chaco has undergone an intensive process of fragmentation, resulting in a shift from landscapes dominated by forests with gaps of rangelands to landscapes where small forest patches are embedded in agricultural lands. Multi-scale fragmentation analysis depicted landscapes in which local exploitation, which perforates forest cover, occurs alongside extensive forest clearings, reducing forests to small and isolated patches surrounded by agricultural lands. In addition, the temporal diminution of Pf's variability along with the increment of the mean slope of the Pf 's scalograms, indicate a simplification of the spatial pattern of forest over time. The observed changes have most likely been the result of the interplay between human activities and environmental constraints, which have shaped the spatial patterns of forests across scales. Based on our results, strategies for the conservation and sustainable

  10. The influence of habitat fragmentation on helminth communities in rodent populations from a Brazilian Mountain Atlantic Forest.

    PubMed

    Cardoso, T S; Simões, R O; Luque, J L F; Maldonado, A; Gentile, R

    2016-07-01

    The influence of habitat structure on helminth communities of three sigomdontinae rodent species (Akodon cursor, A. montensis and Oligoryzomys nigripes) was investigated in forest fragments within an agricultural landscape in south-eastern Brazil. This is a pionner study correlating the occurrence of helminth species of rodent hosts with microhabitat characteristics. Rodents were collected from 12 fragments and in a continuous conserved area. Up to 13 nematode, three cestode and two trematode species were identified, and habitat fragmentation was found to have more influence on the helminth composition of O. nigripes compared to the other two rodent species. Fragmentation appeared to limit the development of some helminths' life cycles, e.g. with some species such as Trichofreitasia lenti, Protospirura numidica, Cysticercus fasciolaris and Avellaria sp., occurring mostly in areas with less anthropic impact. However, fragmentation did not seem to affect the life cycles of other dominant helminths, such as the trematode Canaania obesa, the nematodes Stilestrongylus lanfrediae, S. eta and S. aculeata, and the cestode Rodentolepis akodontis. The helminth community structure followed a nested pattern of distribution in A. montensis and O. nigripes. Stilestrongylus lanfrediae seemed to be more associated with dense understorey, C. obesa with open canopy and dense understorey, and Guerrerostrongylus zetta with organic matter on the ground. Their presence in each area may be explained by aspects of their life cycles that take place in the external environment outside the host.

  11. Mechanisms Driving Galling Success in a Fragmented Landscape: Synergy of Habitat and Top-Down Factors along Temperate Forest Edges

    PubMed Central

    Kelch, Nina-S.; Neves, Frederico S.; Fernandes, G. Wilson

    2016-01-01

    Edge effects play key roles in the anthropogenic transformation of forested ecosystems and their biota, and are therefore a prime field of contemporary fragmentation research. We present the first empirical study to address edge effects on the population level of a widespread galling herbivore in a temperate deciduous forest. By analyzing edge effects on abundance and trophic interactions of beech gall midge (Mikiola fagi Htg.), we found 30% higher gall abundance in the edge habitat as well as lower mortality rates due to decreased top-down control, especially by parasitoids. Two GLM models with similar explanatory power (58%) identified habitat specific traits (such as canopy closure and altitude) and parasitism as the best predictors of gall abundance. Further analyses revealed a crucial influence of light exposure (46%) on top-down control by the parasitoid complex. Guided by a conceptual framework synthesizing the key factors driving gall density, we conclude that forest edge proliferation of M. fagi is due to a complex interplay of abiotic changes and trophic control mechanisms. Most prominently, it is caused by the microclimatic regime in forest edges, acting alone or in synergistic concert with top-down pressure by parasitoids. Contrary to the prevailing notion that specialists are edge-sensitive, this turns M. fagi into a winner species in fragmented temperate beech forests. In view of the increasing proportion of edge habitats and the documented benefits from edge microclimate, we call for investigations exploring the pest status of this galling insect and the modulators of its biological control. PMID:27310599

  12. Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species.

    PubMed

    Prospere, Kurt; McLaren, Kurt P; Wilson, Byron

    2016-10-01

    The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.

  13. Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species

    NASA Astrophysics Data System (ADS)

    Prospere, Kurt; McLaren, Kurt P.; Wilson, Byron

    2016-10-01

    The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.

  14. Hunting and use of terrestrial fauna used by Caiçaras from the Atlantic Forest coast (Brazil)

    PubMed Central

    2009-01-01

    Background The Brazilian Atlantic Forest is considered one of the hotspots for conservation, comprising remnants of rain forest along the eastern Brazilian coast. Its native inhabitants in the Southeastern coast include the Caiçaras (descendants from Amerindians and European colonizers), with a deep knowledge on the natural resources used for their livelihood. Methods We studied the use of the terrestrial fauna in three Caiçara communities, through open-ended interviews with 116 native residents. Data were checked through systematic observations and collection of zoological material. Results The dependence on the terrestrial fauna by Caiçaras is especially for food and medicine. The main species used are Didelphis spp., Dasyprocta azarae, Dasypus novemcinctus, and small birds (several species of Turdidae). Contrasting with a high dependency on terrestrial fauna resources by native Amazonians, the Caiçaras do not show a constant dependency on these resources. Nevertheless, the occasional hunting of native animals represents a complimentary source of animal protein. Conclusion Indigenous or local knowledge on native resources is important in order to promote local development in a sustainable way, and can help to conserve biodiversity, particularly if the resource is sporadically used and not commercially exploited. PMID:19930595

  15. TRANSITIONS IN FOREST FRAGMENTATION: IMPLICATIONS FOR RESTORATION OPPORTUNITIES AT REGIONAL SCALES

    EPA Science Inventory

    Where the potential natural vegetation is continuous forest (e.g., eastern US), a region can be divided into smaller units (e.g., counties, watersheds), and a graph of the proportion of forest in the largest patch versus the proportion in anthropogenic cover can be used as an ind...

  16. Distance from edge determines fruit-feeding butterfly community diversity in afrotropical forest fragments.

    PubMed

    Bossart, J L; Opuni-Frimpong, E

    2009-02-01

    We studied the impact of forest edges on the fruit-feeding butterfly communities of three forest remnants in Ghana, West Africa. Community diversity was assessed using traps baited with fermenting banana. Two 200-m, edge-to-interior transects of five traps each were established in each forest. Sampling spanned 1 yr for a total of 180-210 trap days per site and resulted in 2,634 specimens and 56 species. We found significant support for an effect of forest edge on butterfly diversity. The impact of distance from edge on point estimates of diversity, i.e., total trap captures, weighted species richness, and Simpson's diversity, was unique to each forest. Multivariate analyses, which integrated species composition along with relative abundance and richness, uncovered two broad community types, interior communities (those 100, 150, and 200 m distant from the edge) and exterior communities (edge communities and those 50 m distant), indicating that edge habitat generally extends at least 50 m into the forest. However, effects of edges on community diversity were still detected as far as 100 m into the forest. Three species relatively tolerant of forest degradation emerged as indicators of edge habitat. No species were indicative of core habitat.

  17. Characterization of environmental quality of forest fragments changes in Jundiaí-Mirim river basin-Brazil using the Markov Chain model

    NASA Astrophysics Data System (ADS)

    Hasimoto Fengler, Felipe; Leite de Moraes, Jener Fernando; Irio Ribeiro, Admilson; Peche Filho, Afonso; Araujo de Medeiros, Gerson; Baldin Damame, Desirée; Márcia Longo, Regina

    2015-04-01

    In Brazil is common practice the concurrency of large urban centers water catchment in distant sites. There's no policy to preserve strategic springs in the urban territory. Thus, rural areas, located in the surrounds of municipals, usually provide water and others environment services to the population that reside on cities. The Jundiaí-Mirim river basin, located in the most urbanized state in Brazil, São Paulo, composes an interesting example of this situation. It is located in a rural area near large urban centers, with large industrial parks, near the capital of state. As result of expansion of the cities on its surrounds their lands have had a historic of monetary valorization, making its territories attractive to the housing market. Consequently, the region has an intense process of urbanization that resulted in an increasing environmental disturbance in the areas of natural vegetation. In the other hand, the watershed is the principal water supplier of Jundiaí city, and houses forest remaining of an important Biome in Brazil, the Atlantic Rain Forest. Given the need to preserve its water production capacity and the forest remnants there, this study modeled the environmental quality of forest fragments through indicators of disturbance and evaluated the changes that occur between 1972 and 2013 using the Markov Chain model. The environment quality was determined by nine indicators of environmental disturbance (distance of urban areas, roads, edge land use, size, distance of others forest fragments, land capacity of use, watershed forest cover, number of forest fragments in the watersheds, shape of the forest fragment), obtained by techniques of Geoprocessing, and integrated by Multicriteria Analysis. The Markov Chain model showed a constant tendency of deteriorating in natural vegetation environmental quality, attributed to the intense process of occupation of the river basin. The results showed a historical trend of transformation in forest fragments with

  18. The composition of arbuscular mycorrhizal fungal communities in the roots of a ruderal forb is not related to the forest fragmentation process.

    PubMed

    Grilli, Gabriel; Urcelay, Carlos; Galetto, Leonardo; Davison, John; Vasar, Martti; Saks, Ülle; Jairus, Teele; Öpik, Maarja

    2015-08-01

    Land-use changes and forest fragmentation have strong impact on biodiversity. However, little is known about the influence of new landscape configurations on arbuscular mycorrhizal fungal (AMF) community composition. We used 454 pyrosequencing to assess AMF diversity in plant roots from a fragmented forest. We detected 59 virtual taxa (VT; phylogenetically defined operational taxonomic units) of AMF - including 10 new VT - in the roots of Euphorbia acerensis. AMF communities were mainly composed of members of family Glomeraceae and were similar throughout the fragmented landscape, despite variation in forest fragment size (i.e. small, medium and large) and isolation (i.e. varying pairwise distances). AMF communities in forest fragments were phylogenetically clustered compared with the global, but not regional and local AMF taxon pools. This indicates that non-random community assembly processes possibly related to dispersal limitation at a large scale, rather than habitat filtering or biotic interactions, may be important in structuring the AMF communities. In this system, forest fragmentation did not appear to influence AMF community composition in the roots of the ruderal plant. Whether this is true for AMF communities in soil and the roots of other ecological groups of host plants or in other habitats deserves further study.

  19. Forest Vegetation Monitoring Protocol for National Parks in the North Coast and Cascades Network

    USGS Publications Warehouse

    Woodward, Andrea; Hutten, Karen M.; Boetsch, John R.; Acker, Steven A.; Rochefort, Regina M.; Bivin, Mignonne M.; Kurth, Laurie L.

    2009-01-01

    Plant communities are the foundation for terrestrial trophic webs and animal habitat, and their structure and species composition are an integrated result of biological and physical drivers (Gates, 1993). Additionally, they have a major role in geologic, geomorphologic and soil development processes (Jenny, 1941; Stevens and Walker, 1970). Throughout most of the Pacific Northwest, environmental conditions support coniferous forests as the dominant vegetation type. In the face of anthropogenic climate change, forests have a global role as potential sinks for atmospheric carbon (Goodale and others, 2002). Consequently, knowledge of the status of forests in the three large parks of the NCCN [that is, Mount Rainier (MORA), North Cascades (NOCA), and Olympic (OLYM) National Parks] is fundamental to understanding the condition of Pacific Northwest ecosystems. Diverse climate and soil properties across the Pacific Northwest result in a variety of forest types (Franklin and Dyrness, 1973; Franklin and others, 1988; Henderson and others, 1989, 1992). The mountainous terrain of Mount Rainier, North Cascades, and Olympic National Parks create steep elevational and precipitation gradients within and among the parks: collectively, these parks span from sea level to more than 4,200 m; and include areas with precipitation from 90 to more than 500 cm. The resulting forests range from coastal rainforests with dense understories and massive trees draped with epiphytes; to areas with drought-adapted Ponderosa pines; to high-elevation subalpine fir forests interspersed with meadows just below treeline (table 1). These forests, in turn, are the foundation for other biotic communities constituting Pacific Northwest ecosystems.

  20. Presettlement and modern disturbance regimes in coast redwood forests: Implications for the conservation of old-growth stands

    USGS Publications Warehouse

    Lorimer, Craig G.; Porter, Daniel J.; Madej, Mary Ann; Stuart, John D.; Veirs, Stephen D.; Norman, Steven P.; O'Hara, Kevin L.; Libby, William J.

    2009-01-01

    Coast redwood (Sequoia sempervirens), a western North American conifer of ancient lineage, has a paradoxical combination of late-successional characteristics and strong adaptations to disturbance. Despite its shade tolerance and heavy dominance of the canopy on many sites, redwood saplings are uncommon in upland old-growth stands. Information needed to ensure the conservation of old-growth redwood forests has been limited. In this review paper, we integrate evidence on redwood biology with data on the historic and modern disturbance regimes to help clarify the degree to which key attributes of redwood forests may have been dependent upon periodic disturbance. Available evidence suggests that episodes of fire, flooding, and slope failure prior to European settlement were frequent but predominantly of low to moderate severity and extent, resulting in broadly uneven-aged forests. The majority of fires prior to European settlement were apparently of human origin. Frequency and severity of the major disturbance agents have been radically changed in modern times. Fires have been largely excluded, and flooding has been altered in ways that have often been detrimental to old-growth redwoods on alluvial terraces. However, because of the apparent anthropogenic origin of most presettlement fires, the long-term evolutionary role of fire for coast redwood is ecologically ambiguous. With fire exclusion, redwood possibly could be displaced to some extent on upland sites by increasing abundance of fire-sensitive competitors. Alternatively, redwood may be able to maintain dominance by vegetative sprouting and new seedling establishment on root-wad mounds, fallen logs, and on soil exposed by slope failure. Future research priorities are suggested that will help resolve some of the current ambiguities.

  1. Functional decay in tree community within tropical fragmented landscapes: Effects of landscape-scale forest cover.

    PubMed

    Rocha-Santos, Larissa; Benchimol, Maíra; Mayfield, Margaret M; Faria, Deborah; Pessoa, Michaele S; Talora, Daniela C; Mariano-Neto, Eduardo; Cazetta, Eliana

    2017-01-01

    As tropical rainforests are cleared, forest remnants are increasingly isolated within agricultural landscapes. Understanding how forest loss impacts on species diversity can, therefore, contribute to identifying the minimum amount of habitat required for biodiversity maintenance in human-modified landscapes. Here, we evaluate how the amount of forest cover, at the landscape scale, affects patterns of species richness, abundance, key functional traits and common taxonomic families of adult trees in twenty Brazilian Atlantic rainforest landscapes. We found that as forest cover decreases, both tree community richness and abundance decline, without exhibiting a threshold. At the family-level, species richness and abundance of the Myrtaceae and Sapotaceae were also negatively impacted by the percent forest remaining at the landscape scale. For functional traits, we found a reduction in shade-tolerant, animal-dispersed and small-seeded species following a decrease in the amount of forest retained in landscapes. These results suggest that the amount of forest in a landscape is driving non-random losses in phylogenetic and functional tree diversity in Brazil's remaining Atlantic rainforests. Our study highlights potential restraints on the conservation value of Atlantic rainforest remnants in deforested landscapes in the future.

  2. Heterozygote excess through life history stages in Cestrum miradorense Francey (Solanaceae), an endemic shrub in a fragmented cloud forest habitat.

    PubMed

    Reyes-Zepeda, F; González-Astorga, J; Montaña, C

    2013-01-01

    Comparisons of genetic diversity and population genetic structure among different life history stages provide important information on the effect of the different forces and micro-evolutionary processes that mould diversity and genetic structure after fragmentation. Here we assessed genetic diversity and population genetic structure using 32 allozymic loci in adults, seeds, seedlings and juveniles of eight populations of the micro-endemic shrub Cestrum miradorense in a highly fragmented cloud forest in central-eastern Mexico. We expected that due to its long history or rarity, this species may have endured the negative effects of fragmentation and would show moderate to high levels of genetic diversity. High genetic diversity (H(e) = 0.445 ± 0.03), heterozygote excess (F(IT) = -0.478 ± 0.034, F(IS) = -0.578 ± 0.023) and low population differentiation (F(ST) = 0.064 ± 0.011) were found. Seeds had higher genetic diversity (H(e) = 0.467 ± 0.05) than the later stages (overall mean for adults, seedlings and juveniles H(e) = 0.438 ± 0.08). High gene flow was observed despite the fact that the fragmentation process began more than 100 years ago. We conclude that the high genetic diversity was the result of natural selection, which favours heterozygote excess in all stages, coupled with a combination of a reproductive system and seed/pollen dispersal mechanisms that favour gene flow.

  3. Mating patterns and pollinator mobility are critical traits in forest fragmentation genetics.

    PubMed

    Breed, M F; Ottewell, K M; Gardner, M G; Marklund, M H K; Dormontt, E E; Lowe, A J

    2015-08-01

    Most woody plants are animal-pollinated, but the global problem of habitat fragmentation is changing the pollination dynamics. Consequently, the genetic diversity and fitness of the progeny of animal-pollinated woody plants sired in fragmented landscapes tend to decline due to shifts in plant-mating patterns (for example, reduced outcrossing rate, pollen diversity). However, the magnitude of this mating-pattern shift should theoretically be a function of pollinator mobility. We first test this hypothesis by exploring the mating patterns of three ecologically divergent eucalypts sampled across a habitat fragmentation gradient in southern Australia. We demonstrate increased selfing and decreased pollen diversity with increased fragmentation for two small-insect-pollinated eucalypts, but no such relationship for the mobile-bird-pollinated eucalypt. In a meta-analysis, we then show that fragmentation generally does increase selfing rates and decrease pollen diversity, and that more mobile pollinators tended to dampen these mating-pattern shifts. Together, our findings support the premise that variation in pollinator form contributes to the diversity of mating-pattern responses to habitat fragmentation.

  4. Different pollinator assemblages ensure reproductive success of Cleisostoma linearilobatum (Orchidaceae) in fragmented holy hill forest and traditional tea garden.

    PubMed

    Zhou, Xiang; Liu, Qiang; Han, Jessie Yc; Gao, JiangYun

    2016-02-24

    Orchids are generally recognized to have specialist pollination systems and low fruit set is often thought to be characteristic of the family. In this study, we investigated the reproductive ecology of Cleisostoma linearilobatum, an epiphytic tropical orchid, in a holy hill forest fragment and a traditional tea garden in SW China using comparable methods. C. linearilobatum is self-compatible and dependent on insects for pollination. Fruit production in natural conditions was both pollinator- and resource-limited. However, the natural fruit set remained stable over multiple years at both sites. Pollination observations showed that C. linearilobatum has a generalized pollination system and seven insect species were observed as legitimate pollinators. Although the visit frequencies of different pollinators were different in the two sites, the pollinator assemblages ensured reproductive success of C. linearilobatum in both study sites over multiple years. The results partly explain why C. linearilobatum is so successful in the area, and also suggest that holy hill forest fragments and traditional tea gardens in Xishuangbanna are important in preserving orchids, especially those with generalist pollination.

  5. Parasitic infections of three Mexican howler monkey groups (Alouatta palliata mexicana) living in forest fragments in Mexico.

    PubMed

    Cristóbal-Azkarate, Jurgi; Hervier, Blanca; Vegas-Carrillo, Sira; Osorio-Sarabia, David; Rodríguez-Luna, Ernesto; Veà, Joaquim J

    2010-07-01

    In order to better understand how patterns of parasitism in howler monkeys are affected by forest fragmentation, we carried out a 1 year survey of gastrointestinal parasites in fecal samples from three groups of Mexican howler monkeys inhabiting different forest fragments in the Los Tuxtlas Biosphere Reserve, Mexico. The study groups were chosen because the conditions in which they lived suggested a potentially negative gradient for parasite richness and a positive gradient for levels of parasitism. We report for the first time the presence of Entamoeba coli in Alouatta palliata mexicana and of hookworms (Family Ancylostomidae) in A. palliata. A reduction in home range size and an increase in disturbance was associated with a loss of parasite richness, which in general was high. Parasite prevalence and the proportion of contaminated samples in which each parasite taxon was present was also high in general and there were no differences between groups. A factor related to the generally high levels of parasitism in our study groups could be the high humidity in the study area, because this favors the survival of parasitic free forms and increases the chances of infection. This would also account for the tendency towards higher levels of parasitism observed in the rainy season. Finally we did not find a pattern relating sex and parasitism.

  6. Different pollinator assemblages ensure reproductive success of Cleisostoma linearilobatum (Orchidaceae) in fragmented holy hill forest and traditional tea garden

    PubMed Central

    Zhou, Xiang; Liu, Qiang; Han, Jessie Yc; Gao, JiangYun

    2016-01-01

    Orchids are generally recognized to have specialist pollination systems and low fruit set is often thought to be characteristic of the family. In this study, we investigated the reproductive ecology of Cleisostoma linearilobatum, an epiphytic tropical orchid, in a holy hill forest fragment and a traditional tea garden in SW China using comparable methods. C. linearilobatum is self-compatible and dependent on insects for pollination. Fruit production in natural conditions was both pollinator- and resource-limited. However, the natural fruit set remained stable over multiple years at both sites. Pollination observations showed that C. linearilobatum has a generalized pollination system and seven insect species were observed as legitimate pollinators. Although the visit frequencies of different pollinators were different in the two sites, the pollinator assemblages ensured reproductive success of C. linearilobatum in both study sites over multiple years. The results partly explain why C. linearilobatum is so successful in the area, and also suggest that holy hill forest fragments and traditional tea gardens in Xishuangbanna are important in preserving orchids, especially those with generalist pollination. PMID:26907369

  7. [Establishment and development of Tabebuia rosea (Bignoniaceae) seedlings in a semideciduous tropical forest under management, Pacific coast of Mexico].

    PubMed

    Santacruz, Antonio Mora; Valdez Herández, Juan Ignacio; Angeles Pérez, Gregorio; Musálem Santiago, Miguel Angel; Vaquera Huerta, Humberto

    2006-12-01

    We evaluated the effect of soil "scarification" and vegetation clearing treatments on the natural regeneration and initial development of Tabebuia rosea (Bertold) DC. seedlings in a moderate sized semideciduous tropical forest subjected to wood harvesting on the coast of Jalisco, Mexico. The treatments were applied under "seed" trees, and the number of germinated seedlings and their development were evaluated for nine months. Soil "scarification" promoted seed germination and initial seedling development, while the control of the competing vegetation increased the seedling growth and reduced their mortality. These results should be taken into account for the natural regeneration of this species, after clearing, to improve wood production, and should be incorporated into the silvicultural techniques currently developed in the region.

  8. Fate of added nitrate and ammonium-nitrogen entering a Louisiana gulf coast swamp forest

    SciTech Connect

    Lindau, C.W.; De Laune, R.D.; Jones, G.L.

    1988-03-01

    Added /sup 15/N labeled inorganic nitrogen was used to determine the significance of nitrification-denitrification in flooded swamp soil in removing nitrogen. Nitrogen-15 labeled (NH/sub 2/)/sub 2/SO/sub 4/ and KNO/sub 3/ were added to replicated plots in a swamp forest receiving agricultural runoff. Nitrous oxide and N/sub 2/ fluxes were measured and maximum fluxes were estimated at 24g N/m/sup 2/ x yr and 110 g N/m/sup 2/ x yr, respectively. The capacity of the swamp forest to remove large quantities of nitrogen via nitrification-denitrification processes was demonstrated.

  9. Secondary seed dispersal by dung beetles in an Amazonian forest fragment of Colombia: influence of dung type and edge effect.

    PubMed

    Santos-Heredia, Carolina; Andresen, Ellen; Stevenson, Pablo

    2011-12-01

    Seeds of many plant species are secondarily dispersed by dung beetles, but the outcome of this interaction is highly context-specific. Little is known about how certain anthropogenic disturbances affect this plant-animal interaction. The aims of this study were to assess the effect of dung type on secondary dispersal by dung beetles in a forest fragment, and to determine whether this interaction is affected by edge effects. Using pitfall traps, we captured dung beetles attracted to dung of 2 frugivorous mammals: woolly monkeys and howler monkeys. We found differences between both dung beetle assemblages, but these differences were not consistent in time. Using seeds surrounded by both dung types, we carried out a field experiment using seeds of 2 plant species. We found that the probability of secondary dispersal by dung beetles was higher for seeds placed in woolly monkey dung. Finally, we carried out a field experiment using plastic beads as seed mimics to assess edge effects. We found that secondary seed dispersal by dung beetles was negatively affected by edges. The disruption of plant-animal interactions along anthropogenic forest edges could have long-term negative effects on forest dynamics by affecting processes of regeneration.

  10. Forest-stressing climate factors on the US West Coast as simulated by CMIP5

    NASA Astrophysics Data System (ADS)

    Rupp, D. E.; Buotte, P.; Hicke, J. A.; Law, B. E.; Mote, P.; Sharp, D.; Zhenlin, Y.

    2013-12-01

    The rate of forest mortality has increased significantly in western North America since the 1970s. Causes include insect attacks, fire, and soil water deficit, all of which are interdependent. We first identify climate factors that stress forests by reducing photosynthesis and hydraulic conductance, and by promoting bark beetle infestation and wildfire. Examples of such factors may be two consecutive years of extreme summer precipitation deficit, or prolonged vapor pressure deficit exceeding some threshold. Second, we quantify the frequency and magnitude of these climate factors in 20th and 21st century climates, as simulated by global climate models (GCMs) in Coupled Model Intercomparison Project phase 5 (CMIP5), of Washington, Oregon, and California in the western US. Both ';raw' (i.e., original spatial resolution) and statistically downscaled simulations are considered, the latter generated using the Multivariate Adaptive Constructed Analogs (MACA) method. CMIP5 models that most faithfully reproduce the observed historical statistics of these climate factors are identified. Furthermore, significant changes in the statistics between the 20th and 21st centuries are reported. A subsequent task will be to use a selected subset of MACA-downscaled CMIP5 simulations to force the Community Land Model, version 4.5 (CLM 4.5). CLM 4.5 will be modified to better simulate forest mortality and to couple CLM with an economic model. The ultimate goal of this study is to understand the interactions and the feedbacks by which the market and the forest ecosystem influence each other.

  11. From the forest to the sea and back again: Biogeochemistry in the Oregon Coast Range

    EPA Science Inventory

    Variations in plant community composition across the landscape can influence nutrient retention and loss at the watershed scale. A striking example of plant species influence is the role of N2-fixing red alder (Alnus rubra) in the biogeochemistry of Pacific Northwest forests. A...

  12. Pollinator limitation and the effect of breeding systems on plant reproduction in forest fragments

    NASA Astrophysics Data System (ADS)

    Nayak, K. Geetha; Davidar, Priya

    2010-03-01

    Reproduction of plants in fragmented habitats may be limited because of lower diversity or abundance of pollinators, and/or variation in local plant density. We assessed natural fruit set and pollinator limitation in ten species of woody plants in natural and restored fragments in the Pondicherry region of southern India, to see whether breeding system of plants (self-compatible and self-incompatible) affected fruit set. We tested whether the number of flowering individuals in the fragments affected the fruit set and further examined the adult and sapling densities of self-compatible (SC) and self-incompatible (SI) species. We measured the natural level of fruit set and pollinator limitation (calculated as the difference in fruit set between hand cross-pollinated and naturally pollinated flowers). Our results demonstrate that there was a higher level of pollinator limitation and hence lower levels of natural fruit set in self-incompatible species as compared to self-compatible species. However, the hand cross-pollinated flowers in SC and SI species produced similar levels of fruit set, further indicating that lower fruit set was due to pollinator limitation and not due to lack of cross-compatible individuals in the fragments. There was no significant relation between number of flowering individuals and the levels of natural fruit set, except for two species Derris ovalifolia, Ixora pavetta. In these species the natural fruit set decreased with increasing population size, again indicating pollinator limitation. The adult and sapling densities in self-compatible species were significantly higher than in self-incompatible species. These findings indicate that the low reproductive output in self-incompatible species may eventually lead to lower population sizes. Restoration of pollinator services along with plant species in fragmented habitats is important for the long-term conservation of biodiversity.

  13. Forest structure and litter production of naturally re-generated white mangrove Avicennia marina in sub-tropical estuarine coast.

    PubMed

    Abu Hena, M K; Sidik, B Japar; Idris, M H; Nesarul, M H; Aysha, A; Islam, M S; Nazmul, H

    2015-09-01

    The present work deals with plant structure, phenology, litter production and decomposition of mangrove Avicennia marina in the newly re-generated mangrove forest in sub-tropical coast. The natural generation in this accreted coastal land of mono-specific A. marina forest stand was prominent, with 45% seedlings and 32% saplings. Peak flowering and fruiting were noticed in May and August, respectively. Reproductive components contribute countable percent into the total litter production during the peak flowering (60%) and fruiting (86%) season. The percentage of leaf litter fall fluctuated throughout the year and contributed 13-99% (73% in average) of the total litter production of 11.53 tones ha(-1)'yr(-1). The total litter production differed with season and influenced by local climate, pore water salinity and phenology of the mangrove. The naturally generated young (7 years) A. marina with 1.8 m height produced more leaf litter as compared to similar tree height elsewhere. Decomposition rate was related to season, with higher litter loss during rainy season which could help cycling nutrients and support estuarine food web by supplying organic matter into the sub-tropical coastal environment.

  14. Temporal Changes in Forest Contexts at Multiple Extents: Three Decades of Fragmentation in the Gran Chaco (1979-2010), Central Argentina

    PubMed Central

    Frate, Ludovico; Acosta, Alicia T. R.; Cabido, Marcelo; Hoyos, Laura; Carranza, Maria Laura

    2015-01-01

    The context in which a forest exists strongly influences its function and sustainability. Unveiling the multi-scale nature of forest fragmentation context is crucial to understand how human activities affect the spatial patterns of forests across a range of scales. However, this issue remains almost unexplored in subtropical ecosystems. In this study, we analyzed temporal changes (1979–2010) in forest contexts in the Argentinean dry Chaco at multiple extents. We classified forests over the last three decades based on forest context amount (Pf) and structural connectivity (Pff), which were measured using a moving window approach fixed at eight different extents (from local, ~ 6 ha, to regional, ~ 8300 ha). Specific multi-scale forest context profiles (for the years 1979 and 2010) were defined by projecting Pf vs. Pff mean values and were compared across spatial extents. The distributions of Pf across scales were described by scalograms and their shapes over time were compared. The amount of agricultural land and rangelands across the scales were also analyzed. The dry Chaco has undergone an intensive process of fragmentation, resulting in a shift from landscapes dominated by forests with gaps of rangelands to landscapes where small forest patches are embedded in agricultural lands. Multi-scale fragmentation analysis depicted landscapes in which local exploitation, which perforates forest cover, occurs alongside extensive forest clearings, reducing forests to small and isolated patches surrounded by agricultural lands. In addition, the temporal diminution of Pf’s variability along with the increment of the mean slope of the Pf ‘s scalograms, indicate a simplification of the spatial pattern of forest over time. The observed changes have most likely been the result of the interplay between human activities and environmental constraints, which have shaped the spatial patterns of forests across scales. Based on our results, strategies for the conservation and

  15. Testing Dragonflies as Species Richness Indicators in a Fragmented Subtropical Atlantic Forest Environment.

    PubMed

    Renner, S; Sahlén, G; Périco, E

    2016-06-01

    We surveyed 15 bodies of water among remnants of the Atlantic Forest biome in southern Brazil for adult dragonflies and damselflies to test whether an empirical selection method for diversity indicators could be applied in a subtropical ecosystem, where limited ecological knowledge on species level is available. We found a regional species pool of 34 species distributed in a nested subset pattern with a mean of 11.2 species per locality. There was a pronounced difference in species composition between spring, summer, and autumn, but no differences in species numbers between seasons. Two species, Homeoura chelifera (Selys) and Ischnura capreolus (Hagen), were the strongest candidates for regional diversity indicators, being found only at species-rich localities in our surveyed area and likewise in an undisturbed national forest reserve, serving as a reference site for the Atlantic Forest. Using our selection method, we found it possible to obtain a tentative list of diversity indicators without having detailed ecological information of each species, providing a reference site is available for comparison. The method thus allows for indicator species to be selected in blanco from taxonomic groups that are little known. We hence argue that Odonata can already be incorporated in ongoing assessment programs in the Neotropics, which would also increase the ecological knowledge of the group and allow extrapolation to other taxa.

  16. Edge effects in the primate community of the biological dynamics of Forest Fragments Project, Amazonas, Brazil.

    PubMed

    Lenz, Bryan B; Jack, Katharine M; Spironello, Wilson R

    2014-11-01

    While much is known about abiotic and vegetative edge effects in tropical forests, considerably less is known about the impact of forest edges on large mammals. In this study, we examine edge effects in a primate community to determine: 1) the distance from the edge over which edge effects in primate density are detectable, 2) whether individual species exhibit edge effects in their density, and 3) whether biological characteristics can be used to predict primate presence in edge habitats. Given their importance to many primate species, we also examine the influence of the number of large trees. We found edge penetration distances of 150 m for the five species that experienced edge effects, suggesting that primates respond to edge-related changes in the plant community that are known to be strongest over the first 150 m. Four species had higher edge densities: Alouatta macconnelli (folivore-frugivore), Chiropotes chiropotes (frugivorous seed predator), Saguinus midas (frugivore-faunivore), and Sapajus apella apella (frugivore-faunivore); one species' density was lower: Ateles paniscus (frugivore); and the final species, Pithecia chrysocephala (frugivorous seed predator), did not show an edge-related pattern. The lone significant relationship between the biological characteristics examined (body weight, diet, group size, and home range size) and primate presence in edge habitats was a negative relationship with the amount of fruit consumed. Though we did not examine primate responses to edges that border a denuded matrix, we have shown that edges influence primate distribution even following decades of secondary forest regeneration at habitat edges.

  17. Bat assemblages from three Atlantic Forest fragments in Rio de Janeiro state, Southeastern Brazil

    PubMed Central

    Rosa, Daniel Tavares Cassilhas; Vrcibradic, Davor; Avilla, Leonardo dos Santos

    2015-01-01

    Abstract Bat species richness in Neotropical localities is generally higher than that of any other group of mammals, and surveys of local bat assemblages may provide useful data for conservation management plans. Although the bat fauna of the Rio de Janeiro state is currently one of the best known in Brazil, there are several localities not adequately surveyed yet, and most of them are in the mountainous regions and in the northern portion of the state. From January 2008 to November 2009, we conducted surveys of bats in three localities in the state of Rio de Janeiro (municipalities of Varre-Sai, Sumidouro, and Cantagalo), and our fieldwork constitutes the first assessment of the bat assemblages of these localities. Surveys were conducted using mist nets in four different habitat types in each locality (forest interior, forest edge, riparian forest, and open areas [pastures]). We captured a total of 148 individuals in 17 species, 14 genera and 3 families. Among them, 11 species were recorded in Sumidouro, seven in Cantagalo, and nine in Varre-Sai. Although species richness was low compared with previous surveys in other close localities, we recorded species that have been rarely sampled in Southeastern Brazil (e.g., Macrophyllum macrophyllum [Phyllostomidae]). The results reinforce the importance of sampling different habitats in short surveys to improve the number of species registered. PMID:25632263

  18. Trait-mediated seed predation, dispersal and survival among frugivore-dispersed plants in a fragmented subtropical forest, Southwest China.

    PubMed

    Lai, Xin; Guo, Cong; Xiao, Zhishu

    2014-06-01

    By tracking the fate of individual seeds from 6 frugivore-dispersed plants with contrasting seed traits in a fragmented subtropical forest in Southwest China, we explored how rodent seed predation and hoarding were influenced by seed traits such as seed size, seed coat hardness and seed profitability. Post-dispersal seed fates varied significantly among the 6 seed species and 3 patterns were witnessed: large-seeded species with a hard seed coat (i.e. Choerospoadias axillaries and Diospyros kaki var. silvestris) had more seeds removed, cached and then surviving at caches, and they also had fewer seeds predated but a higher proportion of seeds surviving at the source; medium-sized species with higher profitability and thinner seed coat (i.e. Phoebe zhennan and Padus braohypoda) were first harvested and had the lowest probability of seeds surviving either at the source or at caches due to higher predation before or after removal; and small-seeded species with lower profitability (i.e. Elaeocarpus japonicas and Cornus controversa) had the highest probability of seeds surviving at the source but the lowest probability of seeds surviving at caches due to lower predation at the source and lower hoarding at caches. Our study indicates that patterns of seed predation, dispersal and survival among frugivore-dispersed plants are highly determined by seed traits such as seed size, seed defense and seed profitability due to selective predation and hoarding by seed-eating rodents. Therefore, trait-mediated seed predation, dispersal and survival via seed-eating rodents can largely affect population and community dynamics of frugivore-dispersed plants in fragmented forests.

  19. Composition and distribution of ground-dwelling beetles among oak fragments and surrounding pine plantations in a temperate forest of North China.

    PubMed

    Yu, Xiao-Dong; Luo, Tian-Hong; Zhou, Hong-Zhang

    2014-02-01

    In this study, we compared ground-dwelling beetle assemblages (Coleoptera) from a range of different oak fragments and surrounding conifer plantations to evaluate effects of forest size and surrounding matrix habitat in a temperate forest of north China. During 2000, beetles were sampled via pitfall traps within two large oak fragments (ca. 2.0-4.0 ha), two small oak fragments (ca. 0.2-0.4 ha) and two surrounding matrices dominated by pine plantations (>4 ha) in two sites of different aspects. Overall, no significantly negative effects from forest patch size and the surrounding matrix habitat were detected in total species number and abundance of ground-dwelling beetles. However, compared with small oak patches or pine plantations, more species were associated with an affinity for at least one large oak patch of the two aspects. Multivariate regression trees showed that the habitat type better determined the beetle assemblage structure than patch size and aspect, indicating a strong impact of the surrounding matrix. Linear mixed models indicated that species richness and abundance of all ground-dwelling beetles or beetle families showed different responses to the selected environmental variables. Our results suggest that more disturbed sites are significantly poorer in oak forest specialists, which are usually more abundant in large oak fragments and decrease in abundance or disappear in small fragments and surrounding matrix habitats. Thus, it is necessary to preserve a minimum size of forest patch to create conditions characteristic for forest interior, rather than the more difficult task of increasing habitat connectivity.

  20. [Detection of anti-Lassa antibodies in the Western Forest area of the Ivory Coast].

    PubMed

    Akoua-Koffi, C; Ter Meulen, J; Legros, D; Akran, V; Aïdara, M; Nahounou, N; Dogbo, P; Ehouman, A

    2006-10-01

    Lassa fever is an African viral hemorrhagic fever (VHF) known to be endemic in a number of West African countries including Nigeria, Sierra Leone, Liberia and Guinea. Despite having common borders with Liberia and Guinea, Côte d'Ivoire has never reported any cases of Lassa fever. In March 2000, as part of a research project on VHF--mainly yellow fever, Lassa fever and Ebola fever--in Guinea and Cote d'Ivoire, an exploratory survey was conducted to assess knowledge about VHF and immunological status against Lassa virus among forest workers in the Duekoue and Guiglo regions. One hundred and sixty-three male forest workers were interviewed using a questionnaire designed to assess risk factors for VHF exposure and personal medical history over the last 12 months. Detection of IgG antibodies against Lassa virus was performed by immunofluorescence assay with Lassa virus antigens from the Josiah and Las/AV strains. The overall prevalence of IgG antibodies was 26% (42/161). Among the Lassa IgG positive subjects, 38.5% were loggers including 20% that were positive at a serum dilution of 1/40 and 46.7% were national park workers or forest rangers including 69% that were positive at a dilution of 1/40 and more. Forty-one percent of subjects had heard of VHF including 14% who attributed it to animals and 2% who attributed it to plants. Contact with rodents was frequent and more than 50% of subjects had either eaten or skinned rodents. Although the prevalence of anti-Lassa IgG antibodies seemed high in the study population, no conclusion can be about level of exposure to Lassa virus.

  1. Small effect of fragmentation on the genetic diversity of Dalbergia monticola, an endangered tree species of the eastern forest of Madagascar, detected by chloroplast and nuclear microsatellites

    PubMed Central

    Andrianoelina, O.; Favreau, B.; Ramamonjisoa, L.; Bouvet, J.-M.

    2009-01-01

    Background and Aims The oriental forest ecosystem in Madagascar has been seriously impacted by fragmentation. The pattern of genetic diversity was analysed on a tree species, Dalbergia monticola, which plays an important economic role in Madagascar and is one of the many endangered tree species in the eastern forest. Methods Leaves from 546 individuals belonging to 18 small populations affected by different levels of fragmentation were genotyped using eight nuclear (nuc) and three chloroplast (cp) microsatellite markers. Key Results For nuclear microsatellites, allelic richness (R) and heterozygosity (He,nuc) differed between types of forest: R = 7·36 and R = 9·55, He,nuc = 0·64 and He,nuc = 0·80 in fragmented and non-fragmented forest, respectively, but the differences were not significant. Only the mean number of alleles (Na,nuc) and the fixation index FIS differed significantly: Na,nuc = 9·41 and Na,nuc = 13·18, FIS = 0·06 and FIS = 0·15 in fragmented and non-fragmented forests, respectively. For chloroplast microsatellites, estimated genetic diversity was higher in non-fragmented forest, but the difference was not significant. No recent bottleneck effect was detected for either population. Overall differentiation was low for nuclear microsatellites (FST,nuc = 0·08) and moderate for chloroplast microsatellites (FST,cp = 0·49). A clear relationship was observed between genetic and geographic distance (r = 0·42 P < 0·01 and r = 0·42 P = 0·03 for nuclear and chloroplast microsatellites, respectively), suggesting a pattern of isolation by distance. Analysis of population structure using the neighbor-joining method or Bayesian models separated southern populations from central and northern populations with nuclear microsatellites, and grouped the population according to regions with chloroplast microsatellites, but did not separate the fragmented populations. Conclusions Residual diversity and genetic structure of populations of D. monticola in

  2. Seasonal variation of volatile organic compounds exchange above a periurban Holm oak forest on the Mediterranean coast

    NASA Astrophysics Data System (ADS)

    Savi, Flavia; Juráň, Stanislav; Fares, Silvano

    2015-04-01

    Bi-directional exchanges of Volatile Organic Compounds (VOCs) were investigated on a Mediterranean Holm oak forest in Castelporziano presidential estate, a peri-urban forest near the coast of Tyrrhenian sea, 20 Km from Rome downtown, Italy. Two field campaigns were carried out in January and August 2014 to explore VOCs fluxes in two seasons with different climate conditions and physiological activity of plants. Concentration of 23 compounds was measured using a proton transfer reaction - mass spectrometer (PTR-MS). These included biogenic products (BVOC - isoprene, monoterpenes), oxygenated BVOC (OVOC - methanol, acetaldehyde acetone) and VOC of anthropogenic origin (AVOC - acetonitrile, benzene, hexenal, toluene, xylenes). Each half-hour, we switched between measurement at high frequency above the canopy and sampling through a 5-levels gradient from soil to above the canopy. We used the eddy covariance technique to calculate fluxes above the canopy, while gradient measurements were used to estimate in-canopy source and sink distribution by applying an Inverse Lagrangian Transport Model (Karl et al., 2004, J.Geophys.Res). Ozone and NOx concentrations were also measured to better correlate VOCs exchanges with this important secondary pollutant. Low temperatures lead to almost negligible BVOC fluxes during Winter. Summer fluxes were largely represented by BVOC (mainly monoterpenes). The highest fluxes (up to 2.4 nmol m-2 s-1) were recorded in the central hour of the day in response to high light and temperature. Oxygenated compounds (methanol and acetone) showed different behaviour during the two seasons: in Winter a net release of these compounds was observed, while in Summer the canopy acted as a sink for OVOC except for the hottest hours when we observed significant emissions. OVOC source-sink distribution analysis helped identifying the canopy layers which mostly contributed to VOCs exchanges, thus underlining the importance of forest canopies in VOCs exchanges

  3. Alouatta seniculus: density, home range and group structure in a bamboo forest fragment in the Colombian Andes.

    PubMed

    Gómez-Posada, Carolina; Londoño, Jorge Mario

    2012-01-01

    We evaluated population density, group structure and home range of red howler monkeys in a bamboo forest fragment in the Cordillera Central mountain range of Colombia. We estimated a density of 377.7 individuals/km(2), which is a higher density than normally reported for this species. The average home range size was 3.6 ± 1.1 ha. We found large groups (15.1 ± 4.0 individuals) with subgrouping behavior (daily divisions in foraging subgroups), and a high number of adult and subadult individuals of both sexes per group (mean of 5 males and 7 females per group). The small home range and large group size observed may be related to the high density of howler monkeys in this fragment, which we suggest could be the result of limited dispersal opportunities for these monkeys. The results illustrate the great plasticity of the genus Alouatta, which enables the monkeys to live in a wide range of conditions.

  4. Interspecific infanticide and infant-directed aggression by spider monkeys (Ateles hybridus) in a fragmented forest in Colombia.

    PubMed

    Rimbach, Rebecca; Pardo-Martinez, Alejandra; Montes-Rojas, Andres; Di Fiore, Anthony; Link, Andres

    2012-11-01

    Interspecific aggression amongst nonhuman primates is rarely observed and has been mostly related to scenarios of resource competition. Interspecific infanticide is even rarer, and both the ultimate and proximate socio-ecological factors explaining this behavior are still unclear. We report two cases of interspecific infanticide and five cases of interspecific infant-directed aggression occurring in a well-habituated primate community living in a fragmented landscape in Colombia. All cases were initiated by male brown spider monkeys (Ateles hybridus) and were directed toward infants of either red howler monkeys (Alouatta seniculus: n = 6 cases) or white-fronted capuchins (Cebus albifrons: n = 1 case). One individual, a subadult spider monkey male, was involved in all but one case of interspecific infanticide or aggression. Other adult spider monkeys participated in interspecific aggression that did not escalate into potentially lethal encounters. We suggest that competition for food resources and space in a primate community living in high population densities and restricted to a forest fragment of ca. 65 ha might partly be driving the observed patterns of interspecific aggression. On the other hand, the fact that all but one case of interspecific infanticide and aggression involved the only subadult male spider monkey suggests this behavior might either be pathological or constitute a particular case of redirected aggression. Even if the underlying principles behind interspecific aggression and infanticide are poorly understood, they represent an important factor influencing the demographic trends of the primate community at this study site.

  5. [Polymorphism of the cytochrome b gene fragment of mitochondrial DNA of chum salmon Oncorhynchus keta (Walbaum) from the Ola River (northern coast of the Sea of Okhotsk)].

    PubMed

    Bachevskaia, L T; Pereverzeva, V V

    2010-01-01

    Sequencing of 395 bp long fragments of cytochrome b gene occupying the 15396-15790 bp positions of mtDNA, the data on the structure and variability of the studied region in chum salmon from the Ola River (northern coast of the Sea of Okhtosk) were obtained for the first time. Nine haplotype variants and four protein modifications were obtained. The medial net was built reflecting the variability and phylogenetic relationships of haplotypes in the gene pool of the studied population of the chum salmon from the Ola River. Comparative analysis of the published and original data showed that the Ola chum salmon differs from the Canadian salmon ninth genotypically (in structure of cytochrome b gene) and in the amino acid sequence of the studied site of the enzyme.

  6. Enhancement of Carbon Sequestration in west coast Douglas-fir Forests with Nitrogen Fertilization

    NASA Astrophysics Data System (ADS)

    Chen, B.; Jassal, R.; Black, A.; Brummer, C.; Spittlehouse, D.; Nesic, Z.

    2008-12-01

    Fertilization is one of the eligible management practices for C sequestering and hence reducing CO2 emissions under Article 3.4 of the Kyoto Protocol. In the coastal regions of British Columbia, which have very little nitrogen (N) deposition from pollution sources owing to their remote location, and soils deficient in N (Hanley et al., 1996), Douglas-fir stands respond to N fertilization (Brix, 1981; Fisher and Binkley, 2000; Chapin et al., 2002). However, a major concern with N fertilization is the potential loss from the soil surface of the highly potent greenhouse gas N2O, and little is known about such losses in N-fertilized forest soils. While it is necessary to determine and quantify the effects of N fertilization on stand C sequestration, it is also important to address environmental concerns by measuring N2O emissions to determine the net greenhouse gas (GHG) global warming potential (GWP). The GWP of N2O is 296 times (100-year time horizon) greater than that of CO2 (Ehhalt and Prather, 2001), yet there is little information on its net radiative forcing as a result of forest fertilization. We report two years of results on the effects of N fertilization in a chronosequence of three Douglas-fir stands (7, 19 and 58 years old, hereafter referred to as HDF00, HDF88 and DF49, respectively) on net C sequestration or net primary productivity measured using the eddy-covariance technique. DF49 (110 ha) and HDF88 (20 ha) were aerially fertilized with urea at 200 kg N ha-1 on Jan 13 and Feb 17, 2007, respectively, while due to its young age and competing understory, fertilizer to HDF00 (5 ha) was manually applied at 80 g urea/tree (60 kg N ha-1) along the tree drip line on Feb 13-14, 2007. Additionally, we calculate the net change in GHG GWP resulting from fertilization of DF49 by accounting for N2O emissions and energy costs of fertilizer production, transport, and application. We also compare polymer-coated slow-release urea (Environmentally Smart Nitrogen (ESN

  7. Diversity and genetic connectivity among populations of a threatened tree (Dalbergia nigra) in a recently fragmented landscape of the Brazilian Atlantic Forest.

    PubMed

    Resende, Luciana Cunha; Ribeiro, Renata Acácio; Lovato, Maria Bernadete

    2011-09-01

    In this study we evaluated the influence of recent landscape fragmentation on the dynamics of remnant fragments from the Brazilian Atlantic Forest. This biome is one of the richest in the world and has been extensively deforested and fragmented. We sampled five populations of the threatened Dalbergia nigra, a tree endemic to the Brazilian Atlantic Forest, two located in a large reserve of continuous forest and three in fragments of different sizes and levels of disturbance. In order to assess historical changes, considering the longevity of the analyzed species, 119 adults and 116 saplings were genotyped for six microsatellite loci. Lower levels of genetic diversity were found in the most impacted fragments when compared to the most preserved population located inside the reserve, and there was significant genetic structure among the populations studied (pairwise F(ST) = 0.031-0.152; pairwise D(EST) = 0.039-0.301). However, genetic structure among saplings (F ST) = 0.056; D(EST) = 0.231) was significantly lower than among adults (F(ST) = 0.088; D(EST) = 0.275). Estimates of contemporary gene flow based on assignment tests corroborated this result, suggesting that fragmentation led to an increase in gene flow. This connectivity among remnant fragments could mitigate the loss of genetic diversity through a metapopulation dynamic, but the high rate of habitat loss and the unknown long-term genetic effects add uncertainty. These results, taken together with the presence of private alleles in disturbed populations, highlight the importance of preserving the extant fragments.

  8. Old Fragments of Forest Inside an Urban Area Are Able to Keep Orchid Bee (Hymenoptera: Apidae: Euglossini) Assemblages? The Case of a Brazilian Historical City.

    PubMed

    Ferreira, R P; Martins, C; Dutra, M C; Mentone, C B; Antonini, Y

    2013-10-01

    Retention of habitat fragments within the urban matrix can provide critical resources for the maintenance of regional biodiversity while still providing socio-economic value. Euglossini bees are important components in a community as they are important pollinators for economically valuable plants as well as hundreds of orchid species. However, some species are very sensitive to environmental impacts like urbanization. This study presents the role of antique urban fragments in a historical city in Brazil and compares it with a conservation area on the aspects of orchid bee assemblage, such as richness, composition, and abundance. Four fragments inside the city of Ouro Preto and three inside Parque Estadual do Itacolomi (PEIT) were sampled for Euglossini bees. Sorensen similarity index was used to compare community composition. The Mantel test was applied to verify the hypothesis that an urban center is a barrier for the mobility of the individuals. Fourteen Euglossini species from the region were registered. Close to 75% of the sampled bees were collected from the PEIT sampling areas. The fragments presented differences in Euglossini richness and abundance. A majority of the sampled fragments were dominated by the Eulaema cingulata Fabricius, Eulaema nigrita Lepeletier, and Euglossa securigera Dressler species. We found differences on community composition between the fragments localized in PEIT and those located in the urban center. The data suggest that there is a possible flux of individuals between the sampled fragments. The various small forest fragments in Ouro Preto, primarily in backyards, may also serve as stepping stones between sampled fragments.

  9. The utility of contemporary and historical estimates of dispersal in determining response to habitat fragmentation in a tropical forest-dependent bird community.

    PubMed

    Bowie, Rauri C K

    2011-05-01

    It is often assumed that species which exhibit a greater propensity for dispersal are less susceptible to the impacts of habitat fragmentation; however, a growing body of literature suggests that such generalizations should be carefully evaluated as not all species appear to be equally sensitive to fragmentation. In this issue of Molecular Ecology, Callens et al. (2011) take an innovative approach to compare contemporary estimates of dispersal from an extensive mark-recapture and patch occupancy data set with historical estimates derived from multilocus population genetic models for seven sympatric forest-dependent species in the Taita Hills, Africa. As has been observed for forest-dependent species from the Amazon, populations of sedentary species were more strongly differentiated and clustered when compared to those of more dispersive taxa. The most intriguing result recovered though, was that the five species with similar historical estimates of gene flow (dispersal) differed substantially in their contemporary dispersal rates, suggesting that for some species the propensity for dispersal has decreased over time. As a consequence, the authors suggest that post-fragmentation estimates of dispersal on their own may not be the best predictors of how habitat fragmentation could affect forest-dependent animal communities.This work significantly advances our understanding of the dynamics of habitat fragmentation and makes a strong case for the need to integrate data on historical processes with contemporary data.

  10. Historical ecology and the conservation of large, hermaphroditic fishes in Pacific Coast kelp forest ecosystems.

    PubMed

    Braje, Todd J; Rick, Torben C; Szpak, Paul; Newsome, Seth D; McCain, Joseph M; Elliott Smith, Emma A; Glassow, Michael; Hamilton, Scott L

    2017-02-01

    The intensive commercial exploitation of California sheephead (Semicossyphus pulcher) has become a complex, multimillion-dollar industry. The fishery is of concern because of high harvest levels and potential indirect impacts of sheephead removals on the structure and function of kelp forest ecosystems. California sheephead are protogynous hermaphrodites that, as predators of sea urchins and other invertebrates, are critical components of kelp forest ecosystems in the northeast Pacific. Overfishing can trigger trophic cascades and widespread ecological dysfunction when other urchin predators are also lost from the system. Little is known about the ecology and abundance of sheephead before commercial exploitation. Lack of a historical perspective creates a gap for evaluating fisheries management measures and marine reserves that seek to rebuild sheephead populations to historical baseline conditions. We use population abundance and size structure data from the zooarchaeological record, in concert with isotopic data, to evaluate the long-term health and viability of sheephead fisheries in southern California. Our results indicate that the importance of sheephead to the diet of native Chumash people varied spatially across the Channel Islands, reflecting modern biogeographic patterns. Comparing ancient (~10,000 calibrated years before the present to 1825 CE) and modern samples, we observed variability and significant declines in the relative abundance of sheephead, reductions in size frequency distributions, and shifts in the dietary niche between ancient and modern collections. These results highlight how size-selective fishing can alter the ecological role of key predators and how zooarchaeological data can inform fisheries management by establishing historical baselines that aid future conservation.

  11. Arthropod prey for riparian associated birds in headwater forests of the Oregon Coast Range

    USGS Publications Warehouse

    Hagar, Joan C.; Li, Judith; Sobota, Janel; Jenkins, Stephanie

    2012-01-01

    Headwater riparian areas occupy a large proportion of the land base in Pacific Northwest forests, and thus are ecologically and economically important. Although a primary goal of management along small headwater streams is the protection of aquatic resources, streamside habitat also is important for many terrestrial wildlife species. However, mechanisms underlying the riparian associations of some terrestrial species have not been well studied, particularly for headwater drainages. We investigated the diets of and food availability for four bird species associated with riparian habitats in montane coastal forests of western Oregon, USA. We examined variation in the availability of arthropod prey as a function of distance from stream. Specifically, we tested the hypotheses that (1) emergent aquatic insects were a food source for insectivorous birds in headwater riparian areas, and (2) the abundances of aquatic and terrestrial arthropod prey did not differ between streamside and upland areas during the bird breeding season. We found that although adult aquatic insects were available for consumption throughout the study period, they represented a relatively small proportion of available prey abundance and biomass and were present in only 1% of the diet samples from only one of the four riparian-associated bird species. Nonetheless, arthropod prey, comprised primarily of insects of terrestrial origin, was more abundant in streamside than upland samples. We conclude that food resources for birds in headwater riparian areas are primarily associated with terrestrial vegetation, and that bird distributions along the gradient from streamside to upland may be related to variation in arthropod prey availability. Because distinct vegetation may distinguish riparian from upland habitats for riparian-associated birds and their terrestrial arthropod prey, we suggest that understory communities be considered when defining management zones for riparian habitat.

  12. Historical ecology and the conservation of large, hermaphroditic fishes in Pacific Coast kelp forest ecosystems

    PubMed Central

    Braje, Todd J.; Rick, Torben C.; Szpak, Paul; Newsome, Seth D.; McCain, Joseph M.; Elliott Smith, Emma A.; Glassow, Michael; Hamilton, Scott L.

    2017-01-01

    The intensive commercial exploitation of California sheephead (Semicossyphus pulcher) has become a complex, multimillion-dollar industry. The fishery is of concern because of high harvest levels and potential indirect impacts of sheephead removals on the structure and function of kelp forest ecosystems. California sheephead are protogynous hermaphrodites that, as predators of sea urchins and other invertebrates, are critical components of kelp forest ecosystems in the northeast Pacific. Overfishing can trigger trophic cascades and widespread ecological dysfunction when other urchin predators are also lost from the system. Little is known about the ecology and abundance of sheephead before commercial exploitation. Lack of a historical perspective creates a gap for evaluating fisheries management measures and marine reserves that seek to rebuild sheephead populations to historical baseline conditions. We use population abundance and size structure data from the zooarchaeological record, in concert with isotopic data, to evaluate the long-term health and viability of sheephead fisheries in southern California. Our results indicate that the importance of sheephead to the diet of native Chumash people varied spatially across the Channel Islands, reflecting modern biogeographic patterns. Comparing ancient (~10,000 calibrated years before the present to 1825 CE) and modern samples, we observed variability and significant declines in the relative abundance of sheephead, reductions in size frequency distributions, and shifts in the dietary niche between ancient and modern collections. These results highlight how size-selective fishing can alter the ecological role of key predators and how zooarchaeological data can inform fisheries management by establishing historical baselines that aid future conservation. PMID:28164155

  13. Mangrove forest against dyke-break-induced tsunami on rapidly subsiding coasts

    NASA Astrophysics Data System (ADS)

    Takagi, Hiroshi; Mikami, Takahito; Fujii, Daisuke; Esteban, Miguel; Kurobe, Shota

    2016-07-01

    Thin coastal dykes typically found in developing countries may suddenly collapse due to rapid land subsidence, material ageing, sea-level rise, high wave attack, earthquakes, landslides, or a collision with vessels. Such a failure could trigger dam-break tsunami-type flooding, or "dyke-break-induced tsunami", a possibility which has so far been overlooked in the field of coastal disaster science and management. To analyse the potential consequences of one such flooding event caused by a dyke failure, a hydrodynamic model was constructed based on the authors' field surveys of a vulnerable coastal location in Jakarta, Indonesia. In a 2 m land subsidence scenario - which is expected to take place in the study area after only about 10-20 years - the model results show that the floodwaters rapidly rise to a height of nearly 3 m, resembling the flooding pattern of earthquake-induced tsunamis. The depth-velocity product criterion suggests that many of the narrow pedestrian paths behind the dyke could experience strong flows, which are far greater than the safe limits that would allow pedestrian evacuation. A couple of alternative scenarios were also considered to investigate how such flood impacts could be mitigated by creating a mangrove belt in front of the dyke as an additional safety measure. The dyke-break-induced tsunamis, which in many areas are far more likely than regular earthquake tsunamis, cannot be overlooked and thus should be considered in disaster management and urban planning along the coasts of many developing countries.

  14. Aerosol characterization over Sundarban mangrove forest at the north-east coast of Bay of Bengal, India

    NASA Astrophysics Data System (ADS)

    Chatterjee, Abhijit; Das, Sanat Kumar; Sarkar, Chirantan; Ghosh, Sanjay; Raha, Sibaji; Singh, Soumendra; Roy, Arindam

    2016-07-01

    A comprehensive study was conducted on chemical characterization of size segregated and cumulative aerosols during winter, 2015 and summer 2016 over a remote mangrove forest at Sundarban at the north-east coast of Bay of Bengal. Aerosols originated from the surf zone at the land-ocean boundary of Sundarban mangrove forest and aerosols advected from Kolkata and other metropolitan and urban cities at Indo-Gangetic Plain were characterized in terms of major water soluble inorganic species. Attempt was made to investigate the combined effect of locally generated sea-salt and advected anthropogenic aerosols could change the pristine marine character at this region during the above mentioned periods. Significant chloride depletion from sea-salt aerosols was observed in coarse and ultrafine mode compared to fine mode in winter whereas reverse trend was observed during summer. On an average the chloride to sodium ratio in PM10 aerosol was found to be around 0.6 which was much lower than that in sea-water. It was observed that non-sea-sulphate and nitrate aerosols were the major species depleting chloride from sea-salt aerosols. This supported the interaction between fresh marine and polluted anthropogenic aerosols. The average concentration of PM10 aerosols was 64 μg m-3 in winter and 89 μg m-3 in summer. Major water soluble ionic species were used for the source apportionment of aerosol during the two seasons. On an average it was observed that 60-70 % of total PM10 aerosols were constituted by the major water soluble ionic species. Emission flux and deposition flux of aerosols were also studied over this remote forest region. It was also observed that anthropogenic ionic species were mostly accumulated in the ultrafine and fine mode region both during winter and summer. On the other hand sea-salt species were mostly accumulated in the coarse mode region. Sulphate aerosol showed bimodal distribution with prominent peaks both at ultrafine/fine and coarse mode region

  15. Effects of Hurricane Katrina on the forest structure of taxodium distichum swamps of the Gulf Coast, USA

    USGS Publications Warehouse

    Middleton, B.A.

    2009-01-01

    Hurricane Katrina pushed mixed Taxodium distichum forests toward a dominance of Taxodium distichum (baldcypress) and Nyssa aquatica (water tupelo) because these species had lower levels of susceptibility to wind damage than other woody species. This study documents the volume of dead versus live material of woody trees and shrubs of T. distichum swamps following Hurricane Katrina along the Gulf Coast of Mississippi and Louisiana. Pearl River Wildlife Management Area near Canton, Mississippi had the highest winds of the study areas, and these forests were located in the northeast quadrant of Hurricane Katrina (sustained wind 151 kph (94 mph)). Jean Lafitte National Historical Park and Preserve south of New Orleans had medium to high winds (sustained winds 111 kph (69 mph) at the New Orleans lakefront). Cat Island National Wildlife Refuge had a lower level of winds and was positioned on the western edge of the storm. The forests at Pearl River and to a lesser extent at Jean Lafitte had the highest amount of structural damage in the study. For Cat Island, Jean Lafitte, and Pearl River, the total volume of dead material (debris) was 50, 80, and 370 m3 ha-1, respectively. The ratio of dead to live volume was 0.010, 0.082, and 0.039, respectively. For both of the dominant species, T. distichum and N. aquatica, the percentage of dead to live volume was less than 1. Subdominant species including Acer rubrum, Liquidambar styraciflua, Quercus lyrata, and Quercus nigra were more damaged by the storm at both Pearl River and Jean Lafitte. Only branches were damaged by Hurricane Katrina at Cat Island. Shrubs such as Morella cerifera, Euonymous sp., and Vaccinium sp. were often killed by the storm, while other species such as Cephalanthus occidentalis, Forestiera acuminata, and Cornus florida were not killed. Despite the fact that Hurricane Katrina was a Category 3 storm and struck Pearl River and Jean Lafitte fairly directly, dominant species of the T. distichum swamps were

  16. Ectoparasites of bats (Mammalia: Chiroptera) in Atlantic forest fragments in north-eastern Brazil.

    PubMed

    Bezerra, Rayanna Hellem Santos; de Vasconcelos, Pedro Fonseca; Bocchiglieri, Adriana

    2016-10-01

    In Brazil, most studies involving parasites of bats (bat flies) treat the mid-west, south-east, and south of the country. This work aimed to characterize the ectoparasites community associated with bats in the Atlantic forest in the state of Sergipe, north-eastern Brazil. Sampling was conducted between January and June 2013 in the Serra de Itabaiana National Park (PNSI) and between November 2013 and June 2015 in the Wildlife Refuge Mata do Junco (RVSMJ). Parasitological indexes were determined, and the influence of host sex and the seasonality in prevalence rates and mean intensity for the most abundant parasites was evaluated. Some 129 parasites were collected in PNSI and 296 in RVSMJ, and 100 and 70.6 %, respectively, belong to the family Streblidae. The differences in parasitological rates in Sergipe in relation to other studies may be associated with the environmental characteristics and the composition of the host community. The influence of sex and the seasonal prevalence of Speiseria ambigua and Trichobius joblingi, associated with Carollia perspicillata, may be associated with a lower rate of female captures and low sampling in the dry season. This is a pioneer study in Sergipe that reveals the occurrence of 16 species of streblids and representatives of Acari and Basilia spp., highlighting the need for more studies to increase the wealth and understanding of host-parasite associations in the state.

  17. Role of edge effect on small mammal populations in a forest fragment

    SciTech Connect

    Wike, L.D.

    2000-06-27

    In many cases, edge effect may determine the distribution and densities of small mammal populations. In 1995 and 1998, a mark and recapture study was conducted at the Savannah River Site (SRS), Aiken, SC, to evaluate the role of forest edge habitat. The area studied was an abandoned home site that had been recently isolated by a timber harvest. Harvest activities left a distinct edge of old field and planted pine contrasting with a relatively xeric, mixed hardwood stand. Trapping was conducted for 17 days in 1995 and 14 days in 1998. Three 30 m by 150 m grids were placed in the clear-cut, edge, and hardwood interior habitats. For both years the principal species captured were Peromyscus gossypinus, P. polionotus, and Neotoma floridana. The edge habitat accounted for approximately 55 percent of all captures and nearly four times as many recaptures as the interior and clear-cut habitats. In 1998, greater numbers of N. floridana were trapped than in 1995. The results indicate that the use of edge habitat can be pronounced even within simple communities. Stewards of managed or restored habitats need to carefully consider the role of edge in these systems. In managed areas such as waste sites, movement of material within the food chain could be reduced by minimizing edge habitat around the points of contamination.

  18. Interspecific Infanticide and Infant-Directed Aggression by Spider Monkeys (Ateles hybridus) in a Fragmented Forest in Colombia

    PubMed Central

    Rimbach, Rebecca; Pardo-Martinez, Alejandra; Montes-Rojas, Andres; Di Fiore, Anthony; Link, Andres

    2012-01-01

    Interspecific aggression amongst nonhuman primates is rarely observed and has been mostly related to scenarios of resource competition. Interspecific infanticide is even rarer, and both the ultimate and proximate socio-ecological factors explaining this behavior are still unclear. We report two cases of interspecific infanticide and five cases of interspecific infant-directed aggression occurring in a well-habituated primate community living in a fragmented landscape in Colombia. All cases were initiated by male brown spider monkeys (Ateles hybridus) and were directed toward infants of either red howler monkeys (Alouatta seniculus: n = 6 cases) or white-fronted capuchins (Cebus albifrons: n = 1 case). One individual, a subadult spider monkey male, was involved in all but one case of interspecific infanticide or aggression. Other adult spider monkeys participated in interspecific aggression that did not escalate into potentially lethal encounters. We suggest that competition for food resources and space in a primate community living in high population densities and restricted to a forest fragment of ca. 65 ha might partly be driving the observed patterns of interspecific aggression. On the other hand, the fact that all but one case of interspecific infanticide and aggression involved the only subadult male spider monkey suggests this behavior might either be pathological or constitute a particular case of redirected aggression. Even if the underlying principles behind interspecific aggression and infanticide are poorly understood, they represent an important factor influencing the demographic trends of the primate community at this study site. Am. J. Primatol. 74:990–997, 2012. © 2012 Wiley Periodicals, Inc. PMID:22767357

  19. Genetic differentiation of Octopus minor (Mollusca, Cephalopoda) off the northern coast of China as revealed by amplified fragment length polymorphisms.

    PubMed

    Yang, J M; Sun, G H; Zheng, X D; Ren, L H; Wang, W J; Li, G R; Sun, B C

    2015-12-02

    Octopus minor (Sasaki, 1920) is an economically important cephalopod that is found in the northern coastal waters of China. In this study, we investigated genetic differentiation in fishery populations using amplified fragment length polymorphisms (AFLPs). A total of 150 individuals were collected from five locations: Dalian (DL), Yan-tai (YT), Qingdao (QD), Lianyungang (LY), and Zhoushan (ZS), and 243 reproducible bands were amplified using five AFLP primer combinations. The percentage of polymorphic bands ranged from 53.33 to 76.08%. Nei's genetic identity ranged from 0.9139 to 0.9713, and the genetic distance ranged from 0.0291 to 0.0900. A phylogenetic tree was constructed using the unweighted pair group method with arithmetic mean, based on the genetic distance. The DL and YT populations originated from one clade, while the QD, LY, and ZS populations originated from another. The results indicate that the O. minor stock consisted of two genetic populations with an overall significantly analogous FST value (0.1088, P < 0.05). Most of the variance was within populations. These findings will be important for more sustainable octopus fisheries, so that this marine resource can be conserved for its long-term utilization.

  20. Does long-distance pollen dispersal preclude inbreeding in tropical trees? Fragmentation genetics of Dysoxylum malabaricum in an agro-forest landscape.

    PubMed

    Ismail, S A; Ghazoul, J; Ravikanth, G; Shaanker, R Uma; Kushalappa, C G; Kettle, C J

    2012-11-01

    Tropical trees often display long-distance pollen dispersal, even in highly fragmented landscapes. Understanding how patterns of spatial isolation influence pollen dispersal and interact with background patterns of fine-scale spatial genetic structure (FSGS) is critical for evaluating the genetic consequences of habitat fragmentation. In the endangered tropical timber tree Dysoxylum malabaricum (Meliaceae), we apply eleven microsatellite markers with paternity and parentage analysis to directly estimate historic gene flow and contemporary pollen dispersal across a large area (216 km(2)) in a highly fragmented agro-forest landscape. A comparison of genetic diversity and genetic structure in adult and juvenile life stages indicates an increase in differentiation and FSGS over time. Paternity analysis and parentage analysis demonstrate high genetic connectivity across the landscape by pollen dispersal. A comparison between mother trees in forest patches with low and high densities of adult trees shows that the frequency of short-distance mating increases, as does average kinship among mates in low-density stands. This indicates that there are potentially negative genetic consequences of low population density associated with forest fragmentation. Single isolated trees, in contrast, frequently receive heterogeneous pollen from distances exceeding 5 km. We discuss the processes leading to the observed patterns of pollen dispersal and the implications of this for conservation management of D. malabaricum and tropical trees more generally.

  1. Biomass, production and woody detritus in an old coast redwood (Sequoia sempervirens) forest

    USGS Publications Warehouse

    Busing, R.T.; Fujimori, T.

    2005-01-01

    We examined aboveground biomass dynamics, aboveground net primary production (ANPP), and woody detritus input in an old Sequoia sempervirens stand over a three-decade period. Our estimates of aboveground biomass ranged from 3300 to 5800 Mg ha-1. Stem biomass estimates ranged from 3000 to 5200 Mg ha-1. Stem biomass declined 7% over the study interval. Biomass dynamics were patchy, with marked declines in recent tree-fall patches <0.05 ha in size. Larger tree-fall patches approaching 0.2 ha in size were observed outside the study plot. Our estimates of ANPP ranged from 6 to 14 Mg ha -1yr-1. Estimates of 7 to 10 Mg ha-1yr -1 were considered to be relatively accurate. Thus, our estimates based on long-term data corroborated the findings of earlier short-term studies. ANPP of old, pure stands of Sequoia was not above average for temperate forests. Even though production was potentially high on a per stem basis, it was moderate at the stand level. We obtained values of 797 m3 ha -1 and 262 Mg ha-1 for coarse woody detritus volume and mass, respectively. Fine woody detritus volume and mass were estimated at 16 m3 ha-1 and 5 Mg ha-1, respectively. Standing dead trees (or snags) comprised 7% of the total coarse detritus volume and 8% of the total mass. Coarse detritus input averaged 5.7 to 6.9 Mg ha -1yr-1. Assuming steady-state input and pool of coarse detritus, we obtained a decay rate constant of 0.022 to 0.026. The old-growth stand of Sequoia studied had extremely high biomass, but ANPP was moderate and the amount of woody detritus was not exceptionally large. Biomass accretion and loss were not rapid in this stand partly because of the slow population dynamics and low canopy turnover rate of Sequoia at the old-growth stage. Nomenclature: Hickman (1993). ?? Springer 2005.

  2. An environmental perspective of the post-tsunami scenario along the coast of Tamil Nadu, India: role of sand dunes and forests.

    PubMed

    Mascarenhas, Antonio; Jayakumar, Seelam

    2008-10-01

    An endeavor to feel the pulse of a coast devastated by a powerful oceanographic event is made. Results of field investigations along Tamil Nadu seaside revealed that the tsunami of December 2004 demolished dwellings within strips ranging from 6 to 132 m (average width, 41 m) from the dune, and flooded up to 862 m (average, 247 m) from the shore. The event damaged sand dunes, ripped dune vegetation, created new water bodies and shattered high value assets. Comparatively, casuarina forests performed remarkably. Uprooting of trees was exclusively restricted to a frontal strip ranging from 5 to 25 m (average width, 14 m) nearest to the shore where the maximum wave run-up was 6.5m above sea level. Sand dunes in general, and casuarina forests in particular, possess an innate capacity to dissipate powerful waves. This inference is supported by (a) negligible over wash along belts characterized by high dune complexes, (b) intact villages shielded by dense forests as well as sand dunes, and (c) maximum destruction of open beach front influenced by intense human activity. In this context, the coastal regulation zone (CRZ) Notification of 1991 offers sufficient scientific validity to be endorsed. However, post-tsunami ecosystem management initiatives lack a scientific basis. Therefore, a coastal hazards policy, that considers adaptation, dune restoration and forested buffer zones, is a sustainable long-term option for Indian coasts.

  3. Edge effects and landscape matrix use by a small mammal community in fragments of semideciduous submontane forest in Mato Grosso, Brazil.

    PubMed

    Santos-Filho, M; Silva, D J da; Sanaiotti, T M

    2008-11-01

    A community of small mammals was studied in seasonal semideciduous submontane forest in the state of Mato Grosso, Brazil. This study evaluated the use of edge and matrix pasture, by different small mammal species. Overall, 31 areas were studied, with a total sampling effort of 33,800 trap x nights. Only seven of the 25 species captured in the study sites were able to use the pasture matrix; we classified these species as generalists. Fourteen species were found to be intermediate in habits, being able to use forest edges. We found only four species habitat specialists, occurring only on transect lines in the interior of the fragment, at least 150 m from the edge. Transects located in the pasture matrix and 50 m from the edge had significantly lower species richness and abundance than transects located in the fragment edge or in the interior of the fragment. All transects located within the fragment had similar species richness and abundance, but transects located 50 m from the edge had slightly lower, but non-significant, species richness than transects located 100 m apart from edges. Rarefaction curves demonstrated that only medium-sized fragments (100-300 ha) reached an asymptote of species accumulation. The other areas require further sampling, or more sampling transect, before species accumulation curves stabilize, due to a continued increase in species number.

  4. Heavy metal concentrations in some macrobenthic fauna of the Sundarbans mangrove forest, south west coast of Bangladesh.

    PubMed

    Ahmed, Kawser; Mehedi, Yousuf; Haque, Rezaul; Mondol, Pulakesh

    2011-06-01

    Heavy metal concentrations in some macrobenthic fauna have been reported for the first time from the Sundarbans mangrove forest, south west coast of Bangladesh, in the northern part of Bay of Bengal. The concentration of Fe, Cu, Zn, Cd and Pb in macrobenthos ranged from 235 ± 10.11 to 1,051 ± 38.42, 3.66 ± 0.89 to 7.55 ± 1.29, 76.8 ± 8.55 to 98.5 ± 6.49, 0.46 ± 0.11 to 0.859 ± 0.2 and 4.66 ± 1.17 to 6.77 ± 2.1 μg/g, respectively. Significant variations (p ≤ 0.05) in heavy metal concentrations have been observed among the mud crab, mudskipper and gastropod. However, heavy metal burdens did not vary significantly among the hermit and horseshoe crabs. In mud crab, horseshoe crab and gastropod, heavy metal concentrations were recorded in the sequence: Fe > Zn > Pb > Cu > Cd. Hermit crab and mudskipper contained heavy metals in the order of Fe > Zn > Cu > Pb > Cd. Fe and Zn concentrations were found significantly (p ≤ 0.05) higher in macrobenthos. The lead (Pb) concentration found in the edible portion of macrobenthos exceeded the international permissible limits certified by the WHO. Bioconcentration factors >1.00 obtained for Fe (17.05 in mudskipper) and Cd (1.87 in gastropod) indicated that these metals were highly bioaccumulated and biomagnified in benthic fauna of Sundarbans. The findings of this study refer to the potential impact of heavy metals in the mangrove ecosystem of Bangladesh.

  5. Prevention educational program of human rabies transmitted by bats in rain forest preserved area of southern Brazilian coast.

    PubMed

    Kikuti, M; Paploski, I A D; Silva, M d C P; de Oliveira, E A; da Silva, A W C; Biondo, A W

    2011-12-01

    Guaraqueçaba city is a rain forest environmental protected area located on the southern coast of Brazil. Recently, the local Animal Health Service has noticed haematophagous bats feeding from humans and domestic animals, as well as bat colonies located in houses and public schools. In 2007, two non-haematophagous bats were tested positive by direct immunofluorescence for rabies in a nearby city. Native fauna and environmental laws protect non-haematophagous bats in Brazilian preserved areas such as Guaraqueçaba, making non-haematophagous bat population control almost impossible. Accordingly, the aim of this study was to evaluate a simple and feasible educational protocol applied by a multi-institutional task force in local elementary schools to prevent rabies transmitted by bats. Information was transmitted to children by video, lectures and oral question-answer section; evaluation was made by written questionnaires to teachers and students. Interinstitutional task force included public and animal health public services, a federal university and the city secretary of environment, of education, of agriculture and of animal health, and also participation of local community. Information was effectively absorbed by children when evaluated just after being given. As important, questionnaires showed that handling and playing with bats at day time was common in several elementary school students, exposing themselves to what may represent higher risk of rabies transmission than haematophagous bat feeding directly from humans. Training of teachers and students may effectively prevent rabies by bats in such communities. Insertion of this subject into science content of local elementary school educational programme was proposed in order to establish a continuing education programme on rabies transmitted by bats in environmental preserved areas.

  6. Association of the occurrence of Brazilian spotted fever and Atlantic rain forest fragmentation in the São Paulo metropolitan region, Brazil.

    PubMed

    Scinachi, Claudia A; Takeda, Gabriela A C G; Mucci, Luís Filipe; Pinter, Adriano

    2017-02-01

    Brazilian Spotted Fever (BSF) is a zoonotic disease caused by the bacterium Rickettsia rickettsii. In the São Paulo Metropolitan Region (SPMR) it is transmitted by Amblyomma aureolatum ticks. In this region, annual lethality of the disease can reach 80% and spatial occurrence depends on environmental factors and more particularly on the presence and interaction of domestic and wild carnivores as well as the presence and characteristics of the remnant Atlantic Rain Forest patches. This study analyzed the association between forest fragmentation and its influence on the risk of occurrence of the disease in the human population. Domestic dogs tested for R. rickettsii antibodies in nine different areas under the influence of different patterns of Rain Forest fragmented landscapes and human occupancy. Landscape metrics were obtained by analyzing satellite images and high-resolution orthophotos. Principal component analysis (PCA) was used to determine among the different landscape variables the one that could best explain the data variance, and the results were tested against canine seroprevalence in order to address disease occurrence risk levels. From 270 canine samples, the seroprevalence ranged from 0 to 37%. PCA showed an inverse correlation between functionally connected large forest patches and the canine seroprevalence for R. rickettsii (p=0.030; Spearman's R=-0.683), while there was a positive correlation between forest border effect and canine seroprevalence (p=0.037; Spearman's R=- 0.909). The further attributed disease occurrence risk level supported the real spatial prevalence of the disease reported for the last eight years (p=0.023; Spearman's R=0.63). The results suggest an important relation of deforestation and fragmentation with the occurrence of BSF in the SPMR.

  7. Dietary variability in the western black crested gibbon (Nomascus concolor) inhabiting an isolated and disturbed forest fragment in Southern Yunnan, China.

    PubMed

    Ni, Qing-Yong; Huang, Bei; Liang, Zong-Li; Wang, Xiao-Wei; Jiang, Xue-Long

    2014-03-01

    Forest fragmentation and isolation can reduce the size of available habitat and lead to lower food availability for some primate species. The persistence of nonhuman primates in fragments depends largely on their ability to adjust their diet in response environmental change. The western black crested gibbon (Nomascus concolor) is distributed in northern Vietnam, northwestern Laos, and southwestern China, but little is known about its diet except from studies in the well-protected forests of Mt. Wuliang and Mt. Ailao, central Yunnan. We studied food abundance and diet over 2 years in a small group surviving in an isolated and disturbed forest at Bajiaohe, southern Yunnan, and drew a comparison with the population at Dazhaizi in Mt. Wuliang. We found that gibbons at Bajiaohe consumed mostly fruit, but did not eat figs, unlike most other gibbon populations. Liana fruits and mature leaves were used as alternative foods during periods of tree fruit scarcity. Our results indicate that gibbons in Bajiaohe respond to habitat fragmentation and isolation by consuming a variety of plant species, depending on those that are locally available, and increasing time spent feeding on fruits of trees and lianas rather than increasing time spent consuming leaves.

  8. Forest carbon response to management scenarios intended to mitigate GHG emissions and reduce fire impacts in the US West Coast region

    NASA Astrophysics Data System (ADS)

    Hudiburg, T. W.; Law, B. E.; Thornton, P. E.; Luyssaert, S.

    2012-12-01

    US West coast forests are among the most carbon dense biomes in the world and the potential for biomass accumulation in mesic coastal forests is the highest recorded (Waring and Franklin 1979, Hudiburg et al. 2009). Greenhouse gas (GHG) mitigation strategies have recently expanded to include forest woody biomass as bioenergy, with the expectation that this will also reduce forest mortality. We examined forest carbon response and life cycle assessment (LCA) of net carbon emissions following varying combinations of bioenergy management scenarios in Pacific Northwest forests for the period from 2010-2100. We use the NCAR CLM4 model combined with a regional atmospheric forcing dataset and account for future environmental change using the IPCC RCP4.5 and RCP 8.5 scenarios. Bioenergy management strategies include a repeated thinning harvest, a repeated clearcut harvest, and a single salvage harvest in areas with projected insect-related mortality. None of the bioenergy management scenarios reduce net emissions to the atmosphere compared to continued business-as-usual harvest (BAU) by the end of the 21st century. Forest regrowth and reduced fire emissions are not large enough to balance the wood removals from harvest. Moreover, the substitution of wood for fossil fuel energy and products is not large enough to offset the wood losses through decomposition and combustion. However, in some ecoregions (Blue Mountains and East Cascades), emissions from the thinning harvests begin to improve over BAU at the end of the century and could lead to net reductions in those ecoregions over a longer time period (> 100 years). For salvage logging, there is no change compared to BAU emissions by the end of the 21st century because the treatment area is minimal compared to the other treatments and only performed once. These results suggest that managing forests for carbon sequestration will need to include a variety of approaches accounting for forest baseline conditions and in some

  9. Natural vegetation cover in the landscape and edge effects: differential responses of insect orders in a fragmented forest.

    PubMed

    González, Ezequiel; Salvo, Adriana; Valladares, Graciela

    2016-07-22

    Human activities have led to global simplification of ecosystems, among which Neotropical dry forests are some of the most threatened. Habitat loss as well as edge effects may affect insect communities. Here, we analyzed insects sampled with pan traps in 9 landscapes (at 5 scales, in 100-500 m diameter circles) comprising cultivated fields and Chaco Serrano forests, at overall community and taxonomic order level. In total 7043 specimens and 456 species of hexapods were captured, with abundance and richness being directly related to forest cover at 500 m and higher at edges in comparison with forest interior. Community composition also varied with forest cover and edge/interior location. Different responses were detected among the 8 dominant orders. Collembola, Hemiptera, and Orthoptera richness and/or abundance were positively related to forest cover at the larger scale, while Thysanoptera abundance increased with forest cover only at the edge. Hymenoptera abundance and richness were negatively related to forest cover at 100 m. Coleoptera, Diptera, and Hymenoptera were more diverse and abundant at the forest edge. The generally negative influence of forest loss on insect communities could have functional consequences for both natural and cultivated systems, and highlights the relevance of forest conservation. Higher diversity at the edges could result from the simultaneous presence of forest and matrix species, although "resource mapping" might be involved for orders that were richer and more abundant at edges. Adjacent crops could benefit from forest proximity since natural enemies and pollinators are well represented in the orders showing positive edge effects.

  10. The role of sex and age in the architecture of intrapopulation howler monkey-plant networks in continuous and fragmented rain forests.

    PubMed

    Benitez-Malvido, Julieta; Martínez-Falcón, Ana Paola; Dattilo, Wesley; González-DiPierro, Ana María; Lombera Estrada, Rafael; Traveset, Anna

    2016-01-01

    We evaluated the structure of intrapopulation howler monkey-plant interactions by focusing on the plant species consumed by different sex and age classes in continuous and fragmented forests in southern Mexico. For this we used network analysis to evaluate the impact of fragmentation on howler population traits and on resource availability and food choice. A total of 37 tree and liana species and seven plant items (bark, immature fruits, flowers, mature fruits, immature leaves, mature leaves and petioles) were consumed, but their relative consumption varied according to sex and age classes and habitat type. Overall, adult females consumed the greatest number of plant species and items while infants and juveniles the lowest. For both continuous and fragmented forests, we found a nested diet for howler monkey-plant networks: diets of more selective monkeys represent subsets of the diets of other individuals. Nestedness was likely due to the high selectivity of early life stages in specific food plants and items, which contrasts with the generalized foraging behaviour of adults. Information on the extent to which different plant species and primate populations depend on such interactions in different habitats will help to make accurate predictions about the potential impact of disturbances on plant-animal interaction networks.

  11. The role of sex and age in the architecture of intrapopulation howler monkey-plant networks in continuous and fragmented rain forests

    PubMed Central

    Martínez-Falcón, Ana Paola; Dattilo, Wesley; González-DiPierro, Ana María; Lombera Estrada, Rafael; Traveset, Anna

    2016-01-01

    We evaluated the structure of intrapopulation howler monkey-plant interactions by focusing on the plant species consumed by different sex and age classes in continuous and fragmented forests in southern Mexico. For this we used network analysis to evaluate the impact of fragmentation on howler population traits and on resource availability and food choice. A total of 37 tree and liana species and seven plant items (bark, immature fruits, flowers, mature fruits, immature leaves, mature leaves and petioles) were consumed, but their relative consumption varied according to sex and age classes and habitat type. Overall, adult females consumed the greatest number of plant species and items while infants and juveniles the lowest. For both continuous and fragmented forests, we found a nested diet for howler monkey-plant networks: diets of more selective monkeys represent subsets of the diets of other individuals. Nestedness was likely due to the high selectivity of early life stages in specific food plants and items, which contrasts with the generalized foraging behaviour of adults. Information on the extent to which different plant species and primate populations depend on such interactions in different habitats will help to make accurate predictions about the potential impact of disturbances on plant-animal interaction networks. PMID:26989638

  12. Long-term colonization ecology of forest-dwelling species in a fragmented rural landscape – dispersal versus establishment

    PubMed Central

    Lõhmus, Kertu; Paal, Taavi; Liira, Jaan

    2014-01-01

    Species colonization in a new habitat patch is an efficiency indicator of biodiversity conservation. Colonization is a two-step process of dispersal and establishment, characterized by the compatibility of plant traits with landscape structure and habitat conditions. Therefore, ecological trait profiling of specialist species is initially required to estimate the relative importance of colonization filters. Old planted parks best satisfy the criteria of a newly created and structurally matured habitat for forest-dwelling plant species. We sampled species in 230 ancient deciduous forests (source habitat), 74 closed-canopy manor parks (target habitats), 151 linear wooded habitats (landscape corridors), and 97 open habitats (isolating matrix) in Estonia. We defined two species groups of interest: forest (107 species) and corridor specialists (53 species). An extra group of open habitat specialists was extracted for trait scaling. Differing from expectations, forest specialists have high plasticity in reproduction mechanisms: smaller seeds, larger dispersules, complementary selfing ability, and diversity of dispersal vectors. Forest specialists are shorter, less nutrient-demanding and mycorrhizal-dependent, stress-tolerant disturbance-sensitive competitors, while corridor specialists are large-seeded disturbance-tolerant competitors. About 40% of species from local species pools have immigrated into parks. The historic forest area, establishment-related traits, and stand quality enhance the colonization of forest specialists. The openness of landscape and mowing in the park facilitate corridor specialists. Species traits in parks vary between a forest and corridor specialist, except for earlier flowering and larger propagules. Forest species are not dispersal limited, but they continue to be limited by habitat properties even in the long term. Therefore, the shady parts of historic parks should be appreciated as important forest biodiversity-enhancing landscape

  13. Long-term colonization ecology of forest-dwelling species in a fragmented rural landscape - dispersal versus establishment.

    PubMed

    Lõhmus, Kertu; Paal, Taavi; Liira, Jaan

    2014-08-01

    Species colonization in a new habitat patch is an efficiency indicator of biodiversity conservation. Colonization is a two-step process of dispersal and establishment, characterized by the compatibility of plant traits with landscape structure and habitat conditions. Therefore, ecological trait profiling of specialist species is initially required to estimate the relative importance of colonization filters. Old planted parks best satisfy the criteria of a newly created and structurally matured habitat for forest-dwelling plant species. We sampled species in 230 ancient deciduous forests (source habitat), 74 closed-canopy manor parks (target habitats), 151 linear wooded habitats (landscape corridors), and 97 open habitats (isolating matrix) in Estonia. We defined two species groups of interest: forest (107 species) and corridor specialists (53 species). An extra group of open habitat specialists was extracted for trait scaling. Differing from expectations, forest specialists have high plasticity in reproduction mechanisms: smaller seeds, larger dispersules, complementary selfing ability, and diversity of dispersal vectors. Forest specialists are shorter, less nutrient-demanding and mycorrhizal-dependent, stress-tolerant disturbance-sensitive competitors, while corridor specialists are large-seeded disturbance-tolerant competitors. About 40% of species from local species pools have immigrated into parks. The historic forest area, establishment-related traits, and stand quality enhance the colonization of forest specialists. The openness of landscape and mowing in the park facilitate corridor specialists. Species traits in parks vary between a forest and corridor specialist, except for earlier flowering and larger propagules. Forest species are not dispersal limited, but they continue to be limited by habitat properties even in the long term. Therefore, the shady parts of historic parks should be appreciated as important forest biodiversity-enhancing landscape

  14. Allele frequencies and genetic diversity in two groups of wild tufted capuchin monkeys (Cebus apella nigritus) living in an urban forest fragment.

    PubMed

    Amaral, Jeanne Margareth Jimenes; Simões, Aguinaldo Luiz; De Jong, David

    2005-12-30

    There have been numerous studies genetically characterizing Old World Primates using microsatellites. However, few studies have been made of New World species and none on free-ranging Cebus apella, even though it is probably the most widely distributed species of monkey in the New World. The paucity of studies is due, in part, to the lack of polymorphisms described for this species. We studied two groups of wild tufted capuchins, Cebus apella nigritus, which inhabit Mata Santa Teresa, the Ecological Reserve of Ribeirão Preto, a 158-ha forest fragment in a semi-urban zone of Ribeirão Preto, SP, Brazil. Group 1 had about 60 animals, 35 of which were sampled, and group 2 had about 40 animals, 20 of which were sampled. These group sizes are much larger than the published reports of 6-30 for this species, despite, or perhaps due to the isolation and the size of the forest fragment. Allele PEPC59*1 was the most frequent of all alleles at all loci in both groups (55.7 and 55%), allele PEPC8*1 was the most common allele in group 2 (46.9%) and PEPC8*4 in group 1 (41.1%), allele PEPC3*2 was the most common in group 1 (35.7%) and allele PEPC3*4 in group 2 (31.6%). The genetic diversity, considering each locus in each group, varied from 61.9% at locus PEPC59 to 78.6% at locus PEPC3, both in group 1. The mean genetic diversity (H(S)), considering both groups for all of the loci, was 71.1%. The inter-group diversity (F(ST)) was 1.9%, indicating that these groups belong to the same population. These groups apparently have a high genetic diversity, despite their isolation in a limited forest fragment, although more data are needed to adequately characterize this population.

  15. The effect of habitat fragmentation on the genetic structure of a top predator: loss of diversity and high differentiation among remnant populations of Atlantic Forest jaguars (Panthera onca).

    PubMed

    Haag, T; Santos, A S; Sana, D A; Morato, R G; Cullen, L; Crawshaw, P G; De Angelo, C; Di Bitetti, M S; Salzano, F M; Eizirik, E

    2010-11-01

    Habitat fragmentation may disrupt original patterns of gene flow and lead to drift-induced differentiation among local population units. Top predators such as the jaguar may be particularly susceptible to this effect, given their low population densities, leading to small effective sizes in local fragments. On the other hand, the jaguar's high dispersal capabilities and relatively long generation time might counteract this process, slowing the effect of drift on local populations over the time frame of decades or centuries. In this study, we have addressed this issue by investigating the genetic structure of jaguars in a recently fragmented Atlantic Forest region, aiming to test whether loss of diversity and differentiation among local populations are detectable, and whether they can be attributed to the recent effect of drift. We used 13 microsatellite loci to characterize the genetic diversity present in four remnant populations, and observed marked differentiation among them, with evidence of recent allelic loss in local areas. Although some migrant and admixed individuals were identified, our results indicate that recent large-scale habitat removal and fragmentation among these areas has been sufficiently strong to promote differentiation induced by drift and loss of alleles at each site. Low estimated effective sizes supported the inference that genetic drift could have caused this effect within a short time frame. These results indicate that jaguars' ability to effectively disperse across the human-dominated landscapes that separate the fragments is currently very limited, and that each fragment contains a small, isolated population that is already suffering from the effects of genetic drift.

  16. Patterns and predictors of β-diversity in the fragmented Brazilian Atlantic forest: a multiscale analysis of forest specialist and generalist birds.

    PubMed

    Morante-Filho, José Carlos; Arroyo-Rodríguez, Víctor; Faria, Deborah

    2016-01-01

    Biodiversity maintenance in human-altered landscapes (HALs) depends on the species turnover among localities, but the patterns and determinants of β-diversity in HALs are poorly known. In fact, declines, increases and neutral shifts in β-diversity have all been documented, depending on the landscape, ecological group and spatial scale of analysis. We shed some light on this controversy by assessing the patterns and predictors of bird β-diversity across multiple spatial scales considering forest specialist and habitat generalist bird assemblages. We surveyed birds from 144 point counts in 36 different forest sites across two landscapes with different amount of forest cover in the Brazilian Atlantic forest. We analysed β-diversity among points, among sites and between landscapes with multiplicative diversity partitioning of Hill numbers. We tested whether β-diversity among points was related to within-site variations in vegetation structure, and whether β-diversity among sites was related to site location and/or to differences among sites in vegetation structure and landscape composition (i.e. per cent forest and pasture cover surrounding each site). β-diversity between landscapes was lower than among sites and among points in both bird assemblages. In forest specialist birds, the landscape with less forest cover showed the highest β-diversity among sites (bird differentiation among sites), but generalist birds showed the opposite pattern. At the local scale, however, the less forested landscape showed the lowest β-diversity among points (bird homogenization within sites), independently of the bird assemblage. β-diversity among points was weakly related to vegetation structure, but higher β-diversity values were recorded among sites that were more isolated from each other, and among sites with higher differences in landscape composition, particularly in the less forested landscape. Our findings indicate that patterns of bird β-diversity vary across scales

  17. Deforestation and plant diversity of Madagascar's littoral forests.

    PubMed

    Consiglio, Trisha; Schatz, George E; McPherson, Gordon; Lowry, Porter P; Rabenantoandro, Johny; Rogers, Zachary S; Rabevohitra, Raymond; Rabehevitra, David

    2006-12-01

    Few studies have attempted to quantify the reduction or document the floristic composition of forests in Madagascar. Thus, we focused specifically on deforestation and plant diversity in Madagascar's eastern littoral community. We used a data set of approximately 13,500 specimen records compiled from both historical and contemporary collections resulting from recent intensive inventory efforts to enumerate total plant species richness and to analyze the degree of endemism within littoral forests. Change in littoral forest cover from original to current extent was estimated using geographical information systems tools, remote sensing data (satellite imagery and low-elevation digital photography), and environmental data layers. Of the original littoral forest only 10.3% remains in the form of small forest parcels, and only 1.5% of these remaining fragments are included within the existing protected-areas network. Additionally, approximately 13% of Madagascar's total native flora has been recorded from these forests that originally occupied <1% of its total land surface, and over 25% of the 1535 plant species known from littoral forests are endemic to this community. Given the ongoing pressure from human settlement along Madagascar's eastern coast, protection of the remaining forest fragments is critical for their survival. Fifteen of the largest intact littoral forest fragments we identified, collectively representing 41.5% of remaining littoral forest, are among priority sites recommended to the government of Madagascar for plant conservation and incorporation into the protected-areas network.

  18. Population signatures of large-scale, long-term disjunction and small-scale, short-term habitat fragmentation in an Afromontane forest bird.

    PubMed

    Habel, J C; Mulwa, R K; Gassert, F; Rödder, D; Ulrich, W; Borghesio, L; Husemann, M; Lens, L

    2014-09-01

    The Eastern Afromontane cloud forests occur as geographically distinct mountain exclaves. The conditions of these forests range from large to small and from fairly intact to strongly degraded. For this study, we sampled individuals of the forest bird species, the Montane White-eye Zosterops poliogaster from 16 sites and four mountain archipelagos. We analysed 12 polymorphic microsatellites and three phenotypic traits, and calculated Species Distribution Models (SDMs) to project past distributions and predict potential future range shifts under a scenario of climate warming. We found well-supported genetic and morphologic clusters corresponding to the mountain ranges where populations were sampled, with 43% of all alleles being restricted to single mountains. Our data suggest that large-scale and long-term geographic isolation on mountain islands caused genetically and morphologically distinct population clusters in Z. poliogaster. However, major genetic and biometric splits were not correlated to the geographic distances among populations. This heterogeneous pattern can be explained by past climatic shifts, as highlighted by our SDM projections. Anthropogenically fragmented populations showed lower genetic diversity and a lower mean body mass, possibly in response to suboptimal habitat conditions. On the basis of these findings and the results from our SDM analysis we predict further loss of genotypic and phenotypic uniqueness in the wake of climate change, due to the contraction of the species' climatic niche and subsequent decline in population size.

  19. Population signatures of large-scale, long-term disjunction and small-scale, short-term habitat fragmentation in an Afromontane forest bird

    PubMed Central

    Habel, J C; Mulwa, R K; Gassert, F; Rödder, D; Ulrich, W; Borghesio, L; Husemann, M; Lens, L

    2014-01-01

    The Eastern Afromontane cloud forests occur as geographically distinct mountain exclaves. The conditions of these forests range from large to small and from fairly intact to strongly degraded. For this study, we sampled individuals of the forest bird species, the Montane White-eye Zosterops poliogaster from 16 sites and four mountain archipelagos. We analysed 12 polymorphic microsatellites and three phenotypic traits, and calculated Species Distribution Models (SDMs) to project past distributions and predict potential future range shifts under a scenario of climate warming. We found well-supported genetic and morphologic clusters corresponding to the mountain ranges where populations were sampled, with 43% of all alleles being restricted to single mountains. Our data suggest that large-scale and long-term geographic isolation on mountain islands caused genetically and morphologically distinct population clusters in Z. poliogaster. However, major genetic and biometric splits were not correlated to the geographic distances among populations. This heterogeneous pattern can be explained by past climatic shifts, as highlighted by our SDM projections. Anthropogenically fragmented populations showed lower genetic diversity and a lower mean body mass, possibly in response to suboptimal habitat conditions. On the basis of these findings and the results from our SDM analysis we predict further loss of genotypic and phenotypic uniqueness in the wake of climate change, due to the contraction of the species' climatic niche and subsequent decline in population size. PMID:24713824

  20. Use of space, activity patterns, and foraging behavior of red howler monkeys (Alouatta seniculus) in an Andean forest fragment in Colombia.

    PubMed

    Palma, Ana Cristina; Vélez, Adriana; Gómez-Posada, Carolina; López, Harrison; Zárate, Diego A; Stevenson, Pablo R

    2011-10-01

    Howler monkeys are among the most studied primates in the Neotropics, however, behavioral studies including estimation of food availability in Andean forests are scarce. During 12 months we studied habitat use, behavior, and feeding ecology of two groups of red howler monkeys (Alouatta seniculus) in an isolated fragment in the Colombian Andes. We used a combination of focal animal and instantaneous sampling. We estimated fruit production (FP) using phenology transects, and calculated young leaf abundance by observing marked trees. The home range area used by each group was 10.5 and 16.7 ha and daily distances traveled were 431 ± 228 and 458 ± 259 m, respectively. We found that both groups spent most of their time resting (62-64%). Resting time did not increase with leaf consumption as expected using a strategy of energy minimization. We did not find a relationship between daily distances traveled and leaf consumption. However, howlers consumed fruits according to their availability, and the production of young leaves did not predict feeding time on this resource. Overall, our results are similar to those found on other forest types. We found that despite limited FP in Andean forests, this did not lead to a higher intake of leaves, longer resting periods, or shorter traveling distances for red howlers.

  1. NITROGEN EXPORT FROM FORESTED WATERSHEDS IN THE OREGON COAST RANGE: THE ROLE OF N2-FIXING RED ALDER

    EPA Science Inventory

    Variations in plant community composition across the landscape can influence nutrient retention and loss at the watershed scale. A striking example of plant species influence is the role of N2-fixing red alder (Alnus rubra) in the biogeochemistry of Pacific Northwest forests. T...

  2. An evaluation of the impact of forest biomass harvest for biofuels on carbon storage in the US west coast states under different management scenarios

    NASA Astrophysics Data System (ADS)

    Hudiburg, T. M.; Law, B. E.

    2009-12-01

    Mitigation strategies to reduce fossil fuel emissions of carbon dioxide have lead to investigation of alternative sources of fuels. National and state forest policies have been implemented to both reduce risk of wildfire and promote use of forest biomass as a secondary biofuels energy source. However, the cost and biomass availability have been estimated without quantifying the impact on current and future terrestrial carbon balances. This study uses a combination of Federal Inventory Analysis data (FIA) and supplementary plot data for Washington, Oregon and California to quantify the current forest carbon stocks, net ecosystem production (NEP), and net biome production (NBP = NEP - removals) for the period from 2001-2006. Varying management treatments were applied to determine the net cost, carbon debt, and biofuels energy potential. The treatments were designed to meet multiple objectives emphasizing carbon storage, economic gain, or energy production. The hazardous fuels reduction treatment minimizes carbon loss by only harvesting biomass in forested areas classified by moderate to high risk fire condition classes (FRCC class). This scenario assumes no additional harvest in ecoregions characterized by long fire return intervals (>100 years) such as the Coast Range and the West Cascades and limits removals to an 18 in diameter at breast height (DBH). The energy production treatment maximizes biomass removal by harvesting areas regardless of FRCC class and allows removals up to a 24 inch DBH. Statewide estimates of carbon for 2001-2006 prior to harvest scenarios for California, Oregon, and Washington respectively are as follows: 1) Total land-based carbon stocks (excluding soils) averages 1680, 1663, and 1278 Tg C; 2) NEP is positive in most ecoregions averaging 213, 180, and 191 g C m-2 yr-1; 3) Actual harvest removals averaged 2.7, 6.5, and 5.1 Tg C yr-1 for the same period. In Oregon, the amount of biomass available for biofuels varies from 128 g C m-2 in the

  3. Strongyloides infections of humans and great apes in Dzanga-Sangha Protected Areas, Central African Republic and in degraded forest fragments in Bulindi, Uganda.

    PubMed

    Hasegawa, Hideo; Kalousova, Barbora; McLennan, Matthew R; Modry, David; Profousova-Psenkova, Ilona; Shutt-Phillips, Kathryn A; Todd, Angelique; Huffman, Michael A; Petrzelkova, Klara J

    2016-10-01

    DNA sequence analysis was carried out on Strongyloides spp. larvae obtained from fecal samples of local humans, a wild western lowland gorilla (Gorilla gorilla gorilla) and a central chimpanzee (Pan troglodytes troglodytes) inhabiting Dzanga-Sangha Protected Areas (DSPA), Central African Republic, and eastern chimpanzees (Pan troglodytes schweinfurthii) living in degraded forest fragments on farmland in Bulindi, Uganda. From humans, both Strongyloides fuelleborni and Strongyloides stercoralis were recorded, though the former was predominant. Only S. fuelleborni was present in the great apes in both areas. Phylogenetic analysis of partial mtDNA cytochrome c oxidase subunit 1 gene (Cox1) and comparison of 18S rDNA hyper variable region IV (HVR-IV) sequences implied that in DSPA S. fuelleborni populations in humans differ from those in the nonhuman great apes.

  4. Feeding and general activity patterns of a howler monkey (Alouatta palliata) troop living in a forest fragment at Los Tuxtlas, Mexico.

    PubMed

    Estrada, A; Juan-Solano, S; Ortíz Martínez, T; Coates-Estrada, R

    1999-01-01

    The feeding behavior and general activity patterns of a howler monkey troop living in a 3.6 ha forest fragment were studied at Los Tuxtlas, Mexico, for an annual cycle. Monthly samples of their feeding behavior indicated that they used 52 species of 24 plant families as sources of food. Of these, 67% were trees, which accounted for 96% of total feeding time recorded. Ten species of Moraceae, Cecropiaceae, Anacrdiaceae. and Sapotaceae contributed to 70% of the trees used and to almost 90% of feeding time. The number of plant species used per monthly record varied from 7 to 31 with an average of 19.9 species. Young leaves and ripe fruit were the principal items in the monthly diet of howlers and average percent of time spent consuming these plant parts was 46.7% and 34.8%, respectively. The use of tree species was found to be associated to their importance value and to their pattern of spatial dispersal in the study site. Availability of young leaves was fairly constant from month to month, but it presented a seasonal pattern, and there was a significantly lower number of tree species bearing ripe fruit through the year with brief pulses of production. The monthly activity pattern was found to be related to variations in the availability of young leaves and ripe fruit as well as to the values of the intermonthly overlap in plant species used. Resting and feeding presented a bimodal pattern of occurrence throughout the day that seemed to be related to variations in maximum ambient temperatures. Results are discussed in light of the small size and shape of the forest fragment inhabited by the howler troop.

  5. The effects of timber harvesting on the structure and composition of adjacent old-growth coast redwood forest, California, USA

    USGS Publications Warehouse

    Russell, W.H.; Jones, C.

    2001-01-01

    Data collected across timber harvest boundaries on nine sites within the Redwood National and State Park management area in California, USA, were used to estimate the effective size of old-growth coast redwood preserves. Fourteen variables related to stand structure and composition, wildlife habitat, and physical environment were significantly correlated to distance from the timber harvest boundary using multiple regression analysis. A maximum depth of edge influence of 200 m was determined for variables exhibiting a significant correlation to the distance from the harvest edge. A spatial analysis using ArcView indicated that 53% of the old growth preserved within the study area was influenced by edge conditions, leaving 47% as effective old-growth.

  6. Redox potential characterization and soil greenhouse gas concentration across a hydrological gradient in a Gulf coast forest

    USGS Publications Warehouse

    Yu, K.; Faulkner, S.P.; Patrick, W.H.

    2006-01-01

    Soil redox potential (Eh), concentrations of oxygen (O2) and three greenhouse gases (CO2, CH4, and N2O) were measured in the soil profile of a coastal forest at ridge, transition, and swamp across a hydrological gradient. The results delineated a distinct boundary in soil Eh and O2 concentration between the ridge and swamp with essentially no overlap between the two locations. Critical soil Eh to initiate significant CH4 production under this field conditions was about +300 mV, much higher than in the homogenous soils (about -150 mV). The strength of CH4 source to the atmosphere was strong for the swamp, minor for the transition, and negligible or even negative (consumption) for the ridge. Maximum N2O concentration in the soils was found at about Eh +250 mV, and the soil N2O emission was estimated to account for less than 4% for the ridge and transition, and almost negligible for the swamp in the cumulative global warming potential (GWP) of these three gases. The dynamic nature of this study site in response to water table fluctuations across a hydrological gradient makes it an ideal model of impact of future sea level rise to coastal ecosystems. Soil carbon (C) sequestration potential due to increasing soil water content upon sea level rise and subsidence in this coastal forest was likely limited and temporal, and at the expense of increasing soil CH4 production and emission. ?? 2005 Elsevier Ltd. All rights reserved.

  7. Spillover from adjacent crop and forest habitats shapes carabid beetle assemblages in fragmented semi-natural grasslands.

    PubMed

    Schneider, Gudrun; Krauss, Jochen; Boetzl, Fabian A; Fritze, Michael-Andreas; Steffan-Dewenter, Ingolf

    2016-12-01

    Semi-natural grasslands in Europe are insect biodiversity hotspots and important source habitats delivering ecosystem services to adjacent agricultural land by species spillover. However, this spillover might also occur in the opposite direction, affecting the diversity of semi-natural grasslands. This opposite spillover has got little attention in scientific literature even though generalist species penetrating into the grasslands can affect local biotic interactions, community composition and the conservation value of grassland habitats. In this study, we examined spillover effects from two different adjacent habitat types on carabid beetle assemblages in 20 semi-natural calcareous grasslands. The grasslands were either adjacent to a cereal crop field or to a coniferous forest. We found distinct differences in carabid beetle assemblages in calcareous grasslands depending on adjacent habitat type. Species richness and activity density were higher, but the evenness was lower in calcareous grasslands adjacent to crop fields compared with calcareous grasslands adjacent to coniferous forests. Further, we found a strong spillover of carabid beetles from adjacent crop fields after crop harvest, which may result in transiently increased predation pressure and resource competition in calcareous grasslands. Our results highlight that species composition, diversity and presumably ecosystem functions within semi-natural habitats are affected by the type and management of surrounding habitats. This needs to be considered by nature conservation measures, which aim to protect the unique insect communities of semi-natural European grasslands.

  8. Assessing impact of climate change on Mundra mangrove forest ecosystem, Gulf of Kutch, western coast of India: a synergistic evaluation using remote sensing

    NASA Astrophysics Data System (ADS)

    Srivastava, Prashant K.; Mehta, Abhinav; Gupta, Manika; Singh, Sudhir Kumar; Islam, Tanvir

    2015-05-01

    Mangrove cover changes have globally raised the apprehensions as the changes influence the coastal climate as well as the marine ecosystem services. The main goals of this research are focused on the monitoring of land cover and mangrove spatial changes particularly for the Mundra forest in the western coast of Gujarat state, India, which is famous for its unique mangrove bio-diversity. The multi-temporal Indian Remote Sensing (IRS) Linear Imaging Self Scanning (LISS)-II (IRS-1B) and III (IRS P6/RESOURCESAT-1) images captured in the year 1994 and 2010 were utilized for the spatio-temporal analysis of the area. The land cover and mangrove density was estimated by a unique hybrid classification which consists of K means unsupervised following maximum likelihood classification (MLC) supervised classification-based approach. The vegetation and non-vegetation layers has been extracted and separated by unsupervised classification technique while the training-based MLC was applied on the separated vegetation and non-vegetation classes to classify them into 11 land use/land cover classes. The climatic variables of the area involves wind, temperature, dew point, precipitation, and mean sea level investigated for the period of 17 years over the site. To understand the driving factors, the anthropogenic variables were also taken into account such as historical population datasets. The overall analysis indicates a significant change in the frequency and magnitude of sea-level rise from 1994 to 2010. The analysis of the meteorological variables indicates a high pressure and changes in mangrove density during the 17 years of time, which reveals that if appropriate actions are not initiated soon, the Mundra mangroves might become the victims of climate change-induced habitat loss. After analyzing all the factors, some recommendations and suggestions are provided for effective mangrove conservation and resilience, which could be used by forest official to protect this precious

  9. Free-living ixodid ticks in an urban Atlantic Forest fragment, state of Rio de Janeiro, Brazil.

    PubMed

    Pinheiro, Michele da Costa; Lourenço, Elizabete Captivo; Patrício, Priscilla Maria Peixoto; Sá-Hungaro, Iwine Joyce Barbosa de; Famadas, Kátia Maria

    2014-01-01

    As a consequence of the importance of ticks in forests in protected areas, was conducted survey of species of free-living ticks in the Natural Park Municipal Curió, state of Rio de Janeiro, Brazil. Monthly samples were taken by dragging method, dry ice traps and visual search in two transects. Adults and nymphs of Amblyomma cajennense (n= 147), Amblyomma brasiliense (n= 4) and Amblyomma parvum (n= 1) were collected. This is the first occurrence of A. parvum in the state. No correlation was found between the abundance of stages of A. cajennense and rainfall, temperature and relative humidity. The highest abundances of adults were in the months of January and May, and nymphs in September and October. The low diversity of parasites on Curió Park can be attributed to the proximity of households with pets, which would also explain the higher abundance of A. cajennense that is commonly found in areas impacted by anthropogenic pressure.

  10. Occurrence of anti-Leptospira spp. antibodies in Rhipidomys spp. from a forest fragment of the Brazilian Cerrado.

    PubMed

    Gomes, D O; Ramos, G B; Alves, V B A; Ciuffa, A Z; Cuccato, L P; Dos Reis, T F M; Lima, A M C; Gonçalves, M C; Tolesano, G V; Rodrigues, V S; Szabó, M P J

    2017-03-01

    Leptospirosis is a zoonotic disease of world importance, and its transmission depends on the interaction between humans and animals. Given the necessity to investigate potential hosts of Leptospira spp., this study verified the prevalence of different serovars in the species of Rhipidomys spp., a widespread sigmodont rodent in Brazil. The studied population originates from a semi-evergreen forest located in the county of Uberlândia, in the state of Minas Gerais. The microscopic agglutination test (MAT) was performed with 14 serovars. Thirteen out of the 43 wild rodents captured showed a positive agglutination reaction, with a greater prevalence of the serovars Pyrogenes, Copenhageni, and Canicola. This study found a prevalence of 30.3% anti-Leptospira spp. antibodies; all positive animals were reactive to more than one serovar.

  11. Metacommunity composition of web-spiders in a fragmented neotropical forest: relative importance of environmental and spatial effects.

    PubMed

    Baldissera, Ronei; Rodrigues, Everton N L; Hartz, Sandra M

    2012-01-01

    The distribution of beta diversity is shaped by factors linked to environmental and spatial control. The relative importance of both processes in structuring spider metacommunities has not yet been investigated in the Atlantic Forest. The variance explained by purely environmental, spatially structured environmental, and purely spatial components was compared for a metacommunity of web spiders. The study was carried out in 16 patches of Atlantic Forest in southern Brazil. Field work was done in one landscape mosaic representing a slight gradient of urbanization. Environmental variables encompassed plot- and patch-level measurements and a climatic matrix, while principal coordinates of neighbor matrices (PCNMs) acted as spatial variables. A forward selection procedure was carried out to select environmental and spatial variables influencing web-spider beta diversity. Variation partitioning was used to estimate the contribution of pure environmental and pure spatial effects and their shared influence on beta-diversity patterns, and to estimate the relative importance of selected environmental variables. Three environmental variables (bush density, land use in the surroundings of patches, and shape of patches) and two spatial variables were selected by forward selection procedures. Variation partitioning revealed that 15% of the variation of beta diversity was explained by a combination of environmental and PCNM variables. Most of this variation (12%) corresponded to pure environmental and spatially environmental structure. The data indicated that (1) spatial legacy was not important in explaining the web-spider beta diversity; (2) environmental predictors explained a significant portion of the variation in web-spider composition; (3) one-third of environmental variation was due to a spatial structure that jointly explains variation in species distributions. We were able to detect important factors related to matrix management influencing the web-spider beta

  12. Metacommunity Composition of Web-Spiders in a Fragmented Neotropical Forest: Relative Importance of Environmental and Spatial Effects

    PubMed Central

    Baldissera, Ronei; Rodrigues, Everton N. L.; Hartz, Sandra M.

    2012-01-01

    The distribution of beta diversity is shaped by factors linked to environmental and spatial control. The relative importance of both processes in structuring spider metacommunities has not yet been investigated in the Atlantic Forest. The variance explained by purely environmental, spatially structured environmental, and purely spatial components was compared for a metacommunity of web spiders. The study was carried out in 16 patches of Atlantic Forest in southern Brazil. Field work was done in one landscape mosaic representing a slight gradient of urbanization. Environmental variables encompassed plot- and patch-level measurements and a climatic matrix, while principal coordinates of neighbor matrices (PCNMs) acted as spatial variables. A forward selection procedure was carried out to select environmental and spatial variables influencing web-spider beta diversity. Variation partitioning was used to estimate the contribution of pure environmental and pure spatial effects and their shared influence on beta-diversity patterns, and to estimate the relative importance of selected environmental variables. Three environmental variables (bush density, land use in the surroundings of patches, and shape of patches) and two spatial variables were selected by forward selection procedures. Variation partitioning revealed that 15% of the variation of beta diversity was explained by a combination of environmental and PCNM variables. Most of this variation (12%) corresponded to pure environmental and spatially environmental structure. The data indicated that (1) spatial legacy was not important in explaining the web-spider beta diversity; (2) environmental predictors explained a significant portion of the variation in web-spider composition; (3) one-third of environmental variation was due to a spatial structure that jointly explains variation in species distributions. We were able to detect important factors related to matrix management influencing the web-spider beta

  13. Hydrologic monitoring of a landslide-prone hillslope in the Elliott State Forest, Southern Coast Range, Oregon, 2009-2012

    USGS Publications Warehouse

    Smith, Joel B.; Godt, Jonathan W.; Baum, Rex L.; Coe, Jeffrey A.; Burns, William J.; Morse, Michael M.; Sener-Kaya, Basak; Kaya, Murat

    2014-01-01

    The Oregon Coast Range is dissected by numerous unchanneled headwater basins, which can generate shallow landslides and debris flows during heavy or prolonged rainfall. An automated monitoring system was installed in an unchanneled headwater basin to measure rainfall, volumetric water content, groundwater temperature, and pore pressures at 15-minute intervals. The purpose of this report is to describe and present the methods used for the monitoring as well as the preliminary data collected during the period from 2009 to 2012. Observations show a pronounced seasonal variation in volumetric water content and pore pressures. Increases in pore pressures and volumetric water content from dry-season values begin with the onset of the rainy season in the fall (typically early to mid October). High water contents and pore pressures tend to persist throughout the rainy season, which typically ends in May. Heavy or prolonged rainfall during the wet season that falls on already moist soils often generates positive pore pressures that are observed in the deeper instruments. These data provide a record of the basin’s hydrologic response to rainfall and provide a foundation for understanding the conditions that lead to landslide and debris-flow occurrence.

  14. Primate remains from African crowned eagle (Stephanoaetus coronatus) nests in Ivory Coast's Tai Forest: implications for primate predation and early hominid taphonomy in South Africa.

    PubMed

    McGraw, W Scott; Cooke, Catherine; Shultz, Susanne

    2006-10-01

    Understanding the initial processes of deposition can help with interpretations of fossil assemblages. Here we discuss the taphonomy of primate remains collected under 16 nests of African crowned eagles (Stephanoaetus coronatus) in the Tai Forest, Ivory Coast. From 1,200 bones collected, including 669 primate bones, we calculated minimum number of individuals (MNI), survivability profiles, and damage profiles using methods identical to those employed by Sanders et al. (2003 J. Hum. Evol. 44:87-105) in their analysis of bones from eagle nests in Uganda. Crowned eagles leave a consistent taphonomic signature on their prey remains; hence, results from our analysis of the Tai assemblage are similar to those from the Ugandan sample. Hindlimb and cranial bones are relatively abundant in the sample, while ribs, vertebrae, carpals, and tarsals do not survive well. Primate crania typically display puncture marks around the eye, long bones remain largely intact, and scapulae exhibit raked breakage. These data have implications for understanding the dynamic between extant primates and one of their principle predators, as well as the taphonomy of hominid-bearing caves in South Africa. We concur with Berger and Clarke (1995 J. Hum. Evol. 29:275-299) that a large raptor could have been responsible for the death of the Taung child, Australopithecus africanus.

  15. Toxoplasma gondii in domestic and wild animals from forest fragments of the municipality of Natal, northeastern Brazil.

    PubMed

    Fournier, Gislene Fátima da Silva Rocha; Lopes, Marcos Gomes; Marcili, Arlei; Ramirez, Diego Garcia; Acosta, Igor Cunha Lima; Ferreira, Juliana Isabel Giuli da Silva; Cabral, Aline Diniz; Lima, Júlia Tereza Ribeiro de; Pena, Hilda Fátima de Jesus; Dias, Ricardo Augusto; Gennari, Solange Maria

    2014-01-01

    Toxoplasmosis stands out as a global disease that has felines as definitive hosts. In the municipality of Natal, Rio Grande do Norte State, Brazil, two parks are notable for their ecological and social importance. This study aimed to investigate the presence of Toxoplasma gondii in short hair cats, bats and small non-volant mammals in these two ecological reserves. Altogether, biological samples were obtained from 154 mammals, 92 wild animals from both areas and 62 domestic cats of the Parque da Cidade. In total, 22 (53.7%) non-volant wild mammals, 11 (21.5%) bats and 28 (52.8%) cats were positive for IgG anti-T. gondii antibodies using the Modified Agglutination Test (≥ 25). It was possible to detect the presence of T. gondii DNA, by means of a molecular amplification of a B1 gene fragment (155bp), in 92 tissue samples from wild animals, including Didelphis albiventris, Monodelphis domestica, Artibeus lituratus, Carollia perspicillata and Glossophaga soricina. Of the 62 cats examined by the same molecular method, T. gondii DNA could be detected in 4 cats. In this study, it was observed the circulation of T. gondii in wild species and domestic cats, demonstrating the involvement of wild and domestic animals in the cycle of T. gondii.

  16. Habitat and landscape correlates of presence, density, and species richness of birds wintering in forest fragments in Ohio

    USGS Publications Warehouse

    Doherty, P.F.; Grubb, T.C.

    2000-01-01

    We investigated the distribution of wintering woodland bird species in 47 very small, isolated, woodland fragments (0.54-6.01 ha) within an agricultural landscape in north-central Ohio. Our objectives were to determine correlations between temporal, habitat, and landscape variables and avian presence, density, and species richness within the smallest woodlots occupied by such species. Our results suggest that even common species are sensitive to variation in habitat, landscape, and season. Woodlot area explained the most variation in presence, density, and species richness. Shrub cover was also an important predictor variable for presence of the smallest resident birds. Shrub cover might function as both a refuge from predators and as a windbreak, reducing thermal costs in a flat, open landscape. Landscape factors related to isolation and connectedness were also correlated with species presence and density. The species composition of the community changed through the winter, as did the density of individual species, suggesting that the winter season may play an important role in determining the distributions of bird populations across woodlots. The models presented here for Ohio birds in this specific landscape may have biological inference for other species in similar landscapes.

  17. Soil pretreatment and fast cell lysis for direct polymerase chain reaction from forest soils for terminal restriction fragment length polymorphism analysis of fungal communities.

    PubMed

    Cheng, Fei; Hou, Lin; Woeste, Keith; Shang, Zhengchun; Peng, Xiaobang; Zhao, Peng; Zhang, Shuoxin

    Humic substances in soil DNA samples can influence the assessment of microbial diversity and community composition. Using multiple steps during or after cell lysis adds expenses, is time-consuming, and causes DNA loss. A pretreatment of soil samples and a single step DNA extraction may improve experimental results. In order to optimize a protocol for obtaining high purity DNA from soil microbiota, five prewashing agents were compared in terms of their efficiency and effectiveness in removing soil contaminants. Residual contaminants were precipitated by adding 0.6mL of 0.5M CaCl2. Four cell lysis methods were applied to test their compatibility with the pretreatment (prewashing+Ca(2+) flocculation) and to ultimately identify the optimal cell lysis method for analyzing fungal communities in forest soils. The results showed that pretreatment with TNP+Triton X-100+skim milk (100mM Tris, 100mM Na4P2O7, 1% polyvinylpyrrolidone, 100mM NaCl, 0.05% Triton X-100, 4% skim milk, pH 10.0) removed most soil humic contaminants. When the pretreatment was combined with Ca(2+) flocculation, the purity of all soil DNA samples was further improved. DNA samples obtained by the fast glass bead-beating method (MethodFGB) had the highest purity. The resulting DNA was successfully used, without further purification steps, as a template for polymerase chain reaction targeting fungal internal transcribed spacer regions. The results obtained by terminal restriction fragment length polymorphism analysis indicated that the MethodFGB revealed greater fungal diversity and more distinctive community structure compared with the other methods tested. Our study provides a protocol for fungal cell lysis in soil, which is fast, convenient, and effective for analyzing fungal communities in forest soils.

  18. CONTROLS ON WATER CHEMISTRY OF AN OREGON COAST RANGE STREAM

    EPA Science Inventory

    Numerous factors may control losses of dissolved nutrients from forested basins in the Oregon Coast Range. Potentially important factors include forest composition, stand age, forest management, grazing, agriculture, sewage inputs and bedrock types, as well as others perhaps not...

  19. Substrate dependent talitrid amphipods from fragmented beaches on the north coast of Crete (Crustacea, Amphipoda, Talitridae), including a redefinition of the genus Orchestia and descriptions of Orchestia xylino sp. nov. and Cryptorchestia gen. nov.

    PubMed

    Lowry, J K; Fanini, Lucia

    2013-01-01

    Four species of talitrid amphipods (Orchestia montagui Audouin, 1826, Orchestia stephenseni Cecchini, 1928, Orchestia xylino sp. nov. and Talitrus saltator (Montagu, 1808)) are reported from a set of fragmented pocket beaches to the east of Heraklion on the north coast of Crete. Aside from a previous record of O. stephenseni these are the first records of talitrid amphipods from the island of Crete. 2) Along a coastal segment of only 4.36 km, characterised by habitat fragmentation and substrate patchiness, a clear correlation between talitrid species and beach type is indicated. Talitrus saltator occurs only on sandy beaches. Orchestia montagui and O. xylino occur on banquette beaches and O. montagui, O. stephenseni and O. xylino occur on mixed sand/gravel and cobble beaches. 3) The genus Orchestia is redefined and confined to 15 marine supralittoral species from eastern North America, islands in the North-eastern Atlantic, and western-Europe, including the Baltic and the Mediterranean Seas plus a perplexing group in New Zealand. 4) The new genus Cryptorchestia is described, based on nine terrestrial species previously included in the genus Orchestia and occurring in western Europe, the Mediterranean Sea and the Azores and Canary islands in the North-eastern Atlantic. 5) The new species Orchestia xylino sp. nov. is described. 6) An extensive bibliography for the species in this study is provided.

  20. [Trap-nests used by Centris (Heterocentris) terminata Smith (Hymenoptera: Apidae, Centridini) at secondary Atlantic Forest fragments, in Salvador, Bahia State].

    PubMed

    Drummont, Patrícia; Silva, Fabiana O da; Viana, Blandina F

    2008-01-01

    Ninety-five nests of Centris (Heterocentris) terminata Smith were collected in trap-nests, during November/2001 and January/2003, at two fragments (PZGV e CFO-UFBA) of secondary Atlantic Forest, in Salvador, Bahia State (13 degrees 01' W e 38 degrees 30' S). The highest nest frequencies occurred from December to February (summer), with no nests foundations from August to October (winter - early spring). Two-hundred eight adults emerged from 347 brood cells, being 164 males and 116 females (1: 0.42). During the study period sex ratio was male biased (chi2 = 9.342; gl = 10; P < 0.05). C. terminata nested in holes with diameters 6, 8, 10 mm, but 84,2% were constructed in 8 and 10 mm. nests had one to seven cells arranged in a linear series with the cells partitions built with a mixture of sand and resin or oil. Male is significantly smaller than female, which emerges from the first cells constructed. Immature mortality occurred in 14.1% of brood cells (n = 49), of which 13.0% were due fail in development and 1.2% due to parasitism of Coelioxys sp. (Hymenoptera: Megachilidae) e Tetraonyx sp. (Coleoptera: Meloidae). In the study site, weather, mainly pluviosity, rather than natural enemies influenced seasonal population abundance. The long period of nesting activity, local abundance and usage of trap nests, suggest the potential of C. terminata for management aiming at pollination of native and cultivated plants.

  1. Use of a precipitation-runoff model for simulating effects of forest management on streamflow in 11 small drainage basins, Oregon Coast Range

    USGS Publications Warehouse

    Risley, J.C.

    1994-01-01

    The Precipitation-Runoff Modeling System (PRMS) model of the U.S. Geological Survey was used to simulate the hydrologic effects of timber management in 11 small, upland drainage basins of the Coast Range in Oregon. The coefficients of determination for observed and simulated daily flow during the calibration periods ranged from 0.92 for the Flynn Creek Basin to 0.68 for the Priorli Creek Basin; percent error ranged from -0.25 for the Deer Creek Basin to -4.49 for the Nestucca River Basin. The coefficients of determination during the validation periods ranged from 0.90 for the Flynn Creek Basin to 0.66 for the Wind River Basin; percent error during the validation periods ranged from -0.91 for the Flynn Creek Basin to 22.3 for the Priorli Creek Basin. In addition to daily simulations, 42 storms were selected from the time-series periods in which the 11 basins were studied and used in hourly storm-mode simulations. Sources of simulation error included the quality of the input data, deficiencies in the PRMS model-algorithms, and the quality of parameter estimation. Times-series data from the Flynn Creek and Needle Branch Basins, collected during an earlier U.S. Geological Survey paired-watershed study, were used to evaluate the PRMS as a tool for predicting the hydrologic effects of timber-management practices. The Flynn Creek Basin remained forested and undisturbed during the data-collection period, while the Needle Branch Basin had been clearcut 82 percent at a midpoint during the period of data collection. Using the PRMS, streamflow at the Needle Branch Basin was simulated during the postlogging period using prelogging parameter values. Comparison of postlogging observed streamflow with the simulated data showed an increase in annual discharge volume of approximately 8 percent and a small increase in peak flows of from 1 to 2 percent. The simulated flows from the basins studied were generally insensitive to the number of hydrologic-response units used to replicate

  2. Assessment of forest geospatial patterns over the three giant forest areas of China

    USGS Publications Warehouse

    Li, M.-S.; Zhu, Z.-L.; Lu, H.; Xu, D.; Liu, A.-X.; Peng, S.-K.

    2008-01-01

    Geospatial patterns of forest fragmentation over the three traditional giant forested areas of China (Northeastern, southwestern and Southern China) were analyzed comparatively and reported based on a 250-m resolution land cover dataset. Specifically, the spatial patterns of forest fragmentation were characterized by combining geospatial metrics and forest fragmentation models. The driving forces resulting in the differences of the forest spatial patterns were also investigated. Results suggested that forests in southwest China had the highest severity of forest fragmentation, followed by south region and northeast region. The driving forces of forest fragmentation in China were primarily the giant population and improper exploitation of forests. In conclusion, the generated information in the study provided valuable insights and implications as to the fragmentation patterns and the conservation of biodiversity or genes, and the use of the chosen geospatial metrics and forest fragmentation models was quite useful for depicting forest fragmentation patterns. ?? 2008 Northeast Forestry University.

  3. Future scenarios of land-use and land-cover change in the United States--the Marine West Coast Forests Ecoregion

    USGS Publications Warehouse

    Wilson, Tamara S.; Sleeter, Benjamin M.; Sohl, Terry L.; Griffith, Glenn; Acevedo, William; Bennett, Stacie; Bouchard, Michelle; Reker, Ryan; Ryan, Christy; Sayler, Kristi L.; Sleeter, Rachel; Soulard, Christopher E.

    2012-01-01

    conterminous United States, followed by a description of the Marine West Coast Forests Ecoregion, and lastly a description of the data being published as part of this report.

  4. Palynological evidence of the replacement of the hygrophilous forest by field vegetation during the last 7,000 years B.P. in the northern coast of Rio de Janeiro, Brazil.

    PubMed

    Luz, Cynthia F P da; Barth, Ortrud M; Martin, Louis; Silva, Cleverson G; Turcq, Bruno J

    2011-09-01

    Historians claim that European colonizers of the northern coast of Rio de Janeiro State found vast herbaceous fields when arrived in this region. Hypotheses about the origin of these fields include forest burning by the Goitacás indians and periodical floods by the Paraíba do Sul River and the lagoon system. The palynologycal analysis of two lake cores obtained in the municipality of Campos dos Goytacazes revealed opening episodes of hygrophilous forest and the establishment of field vegetation, recorded at ca. 6,500 and ca. 4,000 (14)C yr BP. The partial replacement of forest by field vegetation in the first episode was probably caused by floods of the lower areas during the development of the Holocene lagoon phase. During the second episode, successions of vegetational patterns occurred due to lowering of the sea level. Drying and enlarging of the coastal plain have allowed its colonization by herbs and heliophyte plants. The palynological analysis does not provide any evidence that sustains the theories of use of fire and agricultural activities by indigenous groups during these periods.

  5. Degree of Landscape Fragmentation Influences Genetic Isolation among Populations of a Gliding Mammal

    PubMed Central

    Taylor, Andrea C.; Walker, Faith M.; Goldingay, Ross L.; Ball, Tina; van der Ree, Rodney

    2011-01-01

    Forests and woodlands are under continuing pressure from urban and agricultural development. Tree-dependent mammals that rarely venture to the ground are likely to be highly sensitive to forest fragmentation. The Australian squirrel glider (Petaurus norfolcensis) provides an excellent case study to examine genetic (functional) connectivity among populations. It has an extensive range that occurs in a wide band along the east coast. However, its forest and woodland habitat has become greatly reduced in area and is severely fragmented within the southern inland part of the species' range, where it is recognised as threatened. Within central and northern coastal regions, habitat is much more intact and we thus hypothesise that genetic connectivity will be greater in this region than in the south. To test this we employed microsatellite analysis in a molecular population biology approach. Most sampling locations in the highly modified south showed signatures of genetic isolation. In contrast, a high level of genetic connectivity was inferred among most sampled populations in the more intact habitat of the coastal region, with samples collected 1400 km apart having similar genetic cluster membership. Nonetheless, some coastal populations associated with urbanisation and agriculture are genetically isolated, suggesting the historic pattern observed in the south is emerging on the coast. Our study demonstrates that massive landscape changes following European settlement have had substantial impacts on levels of connectivity among squirrel glider populations, as predicted on the basis of the species' ecology. This suggests that landscape planning and management in the south should be focused on restoring habitat connectivity where feasible, while along the coast, existing habitat connectivity must be maintained and recent losses restored. Molecular population biology approaches provide a ready means for identifying fragmentation effects on a species at multiple scales

  6. Ten-year development of douglas-fir and associated vegetation after different site preparation on coast range clearcuts. Forest Service research paper

    SciTech Connect

    Stein, W.I.

    1995-02-01

    Ten-years results are presented from an operational-sized, replicated experiment in the Coast Ranges of Oregon to determine the effects of six site-preparation methods on the subsequent survival and growth of Douglas-fir and associated species. Site preparation and seedling protection with plastic mesh tubing significantly enhanced tree development. Site preparation also produced large differences in frequency and cover of associated species but only minor differences in the species represented.

  7. Coast Guard

    SciTech Connect

    Meed, R.M.

    1991-10-01

    This paper testifies that water pollution by oil remains significant, and noncompliance with federal regulations to prevent oil pollution continues to be great in the four ports GAO visited. Additionally, the impact of the Coast Guard's efforts to reduce oil spill in unknown because the agency does not compile and analyze inspection and spill data needed to make this determination. Further, the Coast Guard has not been inspecting portions of pipes that transport oil between docks and storage tanks. Coast Guard officials now acknowledge this responsibility.

  8. Coasts under pressure.

    PubMed

    Hinrichsen, D

    1994-01-01

    In most areas of the world, too many people live or play along the coast. Municipal and industrial wastes pollute coastal waters. Rivers spew erosion sediment and pollutants into these waters. Economic development is often the only management strategy for coastal zones, and economic development has little concern for resource degradation and watershed management. 53 countries have coastal management plans, but few have adequately implemented them. Almost 66% of the world's population lives within 150 km of the coast; by 2025, 75% will live as close to the coast. In the US, the coastal population has grown faster than that of the entire US, so that the population density is now almost 400 persons/sq m compared to 275 persons/sq m in 1960. Urbanization continues in the US coastal zones, where 7 of the 10 US largest cities exist. 94% of China's population lives in the eastern 3rd of the country. The population density along China's coast is more than 600/sq km. In Shanghai, it is more than 2000/sq km. Many people are moving from poorer provinces in the central and western regions to the economic free zones and special economic zones along the coast. At any moment, 30-60 million Chinese are moving. Most everyone in southeastern Asia, the Caribbean, and Latin America live in coastal areas. By 2025, the coastal zone between Rio de Janeiro and Sao Paulo will be all urbanized This is also occurring on Chile's coast between Valparaiso and Concepcion. The Mediterranean has the most overcrowded coastline in the developed world. Unchecked development could lead to continuous urban sprawl between Spain and Greece. Development pressures have caused a sizable decline in or a collapse of coastal fisheries. In Asia, all waters within 15 km of the coastline have been overfished. Coral reefs and mangrove forests are being destroyed with inadequate resources targeted for their protection.

  9. 75 FR 13252 - Oregon Coast Provincial Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Oregon Coast Provincial Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Oregon Coast Province Advisory Committee will meet at the Siuslaw National...

  10. Dom Export from Coastal Temperate Bog Forest Watersheds to Marine Ecosystems: Improving Understanding of Watershed Processes and Terrestrial-Marine Linkages on the Central Coast of British Columbia

    NASA Astrophysics Data System (ADS)

    Oliver, A. A.; Giesbrecht, I.; Tank, S. E.; Hunt, B. P.; Lertzman, K. P.

    2014-12-01

    The coastal temperate bog forests of British Columbia, Canada, export high amounts of dissolved organic matter (DOM) relative to the global average. Little is known about the factors influencing the quantity and quality of DOM exported from these forests or the role of this terrestrially-derived DOM in near-shore marine ecosystems. The objectives of this study are to better understand patterns and controls of DOM being exported from bog forest watersheds and its potential role in near-shore marine ecosystems. In 2013, the Kwakshua Watershed Ecosystems Study at Hakai Beach Institute (Calvert Island, BC) began year-round routine collection and analysis of DOM, nutrients, and environmental variables (e.g. conductivity, pH, temperature, dissolved oxygen) of freshwater grab samples from the outlets of seven watersheds draining directly to the ocean, as well as near-shore marine samples adjacent to freshwater outflows. Dissolved organic carbon (DOC) varied across watersheds (mean= 11.45 mg L-1, sd± 4.22) and fluctuated synchronously with seasons and storm events. In general, higher DOC was associated with lower specific UV absorbance (SUVA254; mean= 4.59 L mg-1 m-1, sd± 0.55). The relationship between DOC and SUVA254 differed between watersheds, suggesting exports in DOM are regulated by individual watershed attributes (e.g. landscape classification, flow paths) as well as precipitation. We are using LiDAR and other remote sensing data to examine watershed controls on DOC export. At near-shore marine sites, coupled CTD (Conductivity Temperature Depth) and optical measures (e.g. spectral slopes, slope ratios (SR), EEMs), showed a clear freshwater DOM signature within the system following rainfall events. Ongoing work will explore the relationship between bog forest watershed attributes and DOM flux and composition, with implications for further studies on biogeochemical cycling, carbon budgets, marine food webs, and climate change.

  11. Open and disturbed habitats support higher diversity of Syrphidae (Diptera)? A case study during three yr of sampling in a fragment of Araucaria forest in southern Brazil.

    PubMed

    Souza, Jana Magaly Tesserolli de; Marinoni, Renato Contin; Marinoni, Luciane

    2014-01-01

    The diversity of hoverflies in five different habitats of the Parque Estadual de Vila Velha, Ponta Grossa, Paraná, Brazil, from September 1999 to August 2002 was studied. These five areas had been exposed to various types of anthropogenic disturbance at different times, which resulted in different stages of plant succession. In total, 2,841 specimens of 151 species of Syrphidae were collected using malaise traps. The highest species richness and abundance were found at the edge of the forest (Forest Edge), whereas the lowest was found in the most conserved areas. Evenness values increased along the succession gradient. The accumulation curve of new occurrences of syrphid species nearly approached an asymptote starting on the third month of the third year. Estimates of syrphid species richness using different methods indicated that between 155 and 288 species are found in the study area, according the Michaelis-Menten and the Chao2 estimators, respectively. The richness and abundance of representatives of the subfamily Syrphinae were higher in more open areas, where herbaceous plants predominate. Nineteen hoverfly species can be considered as environmental indicators, as they were collected exclusively or mainly in one of the defined habitat types. The degree of opening of the vegetation seems to be the factor determining the distribution of Syrphidae species, a conclusion based on the finding that grassy clearings in Araucaria Forests had more species. Hence, we conclude that, to become established, Syrphidae communities need conserved mosaic landscapes.

  12. Black bear (Ursus americanus Pallas) feeding damage across timber harvest edges in northern California coast redwood (Sequoia sempervirens[D. Don] Endl.) forests, USA

    USGS Publications Warehouse

    Russell, W.H.; Carnell, K.; McBride, J.R.

    2001-01-01

    Feeding damage to trees by black bears (Ursus americanus Pallas) was recorded in proximity to timber harvest edges in harvested and old-growth stands of coast redwood (Sequoia sempervirens [D. Don] Endl.) in northern California, USA. Bears exhibited distinct preference in their feeding patterns related to stand structure and composition and to distance from the timber-harvest edge. Most damage was recorded within regenerating stands. Regression analysis indicated that density of damaged trees was negatively correlated with distance from timber harvest edges within old-growth stands. A significant negative correlation was also found between the density of trees damaged by bears and habitat diversity (H') as measured by the Shannon diversity index. In addition, bears exhibited preference for pole-size trees (dbh = 10-50 cm) over all other size classes, and coast redwood over other species. In general, damage by bears appeared to act as a natural thinning agent in even-aged stands. No damage was recorded in old-growth stands except in close proximity to the timber-harvest edge where subcanopy recruitment was high.

  13. Fusion of LiDAR and Imagery to Estimate Stand-level Tree Mortality Following Wildfire in a Coast Redwood Forest

    NASA Astrophysics Data System (ADS)

    Bishop, B. D.; Dietterick, B. C.; White, R. A.; Mastin, T.

    2013-12-01

    Discrete-return airborne LiDAR and digital orthophotography are commonly used to assess the condition of vegetation, including change detection following disturbance events, such as wildland fire. Forest managers have a need for information about fire effects and the spatial distribution of mortality following wildfire, but direct assessment from the field is time-consuming and expensive. Remote sensing may be used to estimate varying levels of mortality and provide a more efficient, timely, scalable, and potentially more cost-effective means for post-fire assessment. Similar past studies have generally used an index of fire 'severity' rather than estimating mortality directly. While useful, estimates of severity are not generally sufficient to make stand-level forest management decisions about post-fire response. This study modeled mortality of trees following the Lockheed fire, which burned 3,163 ha in the Santa Cruz Mountains in California from August 12-23, 2009. All trees in forty-seven 0.08 ha continuous forest inventory plots were assessed in the field for three years following the fire. Plot percent mortality of trees 25.4 cm DBH and greater was sorted into three categories: <25%, 25-50%, and >50%. A variety of predictor variables derived from pre- and post-fire airborne LiDAR and 1m resolution color infrared aerial imagery (NAIP) were evaluated. A model using four variables: the normalized difference vegetation index (NDVI) from 2010 NAIP imagery, change in ratio of 95th percentile to mean height, and change in percent of points in two height bins, 11-12 and 14-15m, classified plots with 83% accuracy. All plots in the most severe class (mortality >50%) were correctly classified. Models with variables derived from post-fire LiDAR alone, and NDVI alone, were also examined, and had overall accuracies of 76.6 and 68.1%, respectively. These findings indicate that remote sensing data can be used to estimate and map the distribution of tree mortality following

  14. Coast Guard

    SciTech Connect

    Not Available

    1990-02-01

    GAO found the situation in the Philadelphia and New York ports similar to that in Prince William Sound-neither industry nor the Coast Guard are prepared to respond to major oil spills. This report discusses how this unpreparedness is due to a lack of specificity in the industry and Coast Guard's plan on how to deal with spills of various sizes and Coast Guard authority to require ship owners and operators to have contingency plans or to require changes in existing plans. On the basic of recent experiences, GAO believes that prevention of oil spills rather than responding to them should be the main priority. Experiences in Price William Sound and in Philadelphia, however, show that much needs to be done to improve prevention measures like monitoring and guiding ship movements and using harbor pilots or vessel escorts.

  15. Coast Guard

    SciTech Connect

    Not Available

    1991-09-01

    The 11-million gallon Exxon Valdez oil spill highlighted deficiencies in the nation's ability to contain and recover spilled oil. The Oil Pollution Act of 1990 represents a major effort by Congress to address these deficiencies and to clarify the roles and responsibilities of the private sector and the federal government in preventing, preparing for, and responding to oil spills. This report examines the Coast Guard's efforts to avoid unnecessary and wasteful duplication by coordinating with the private sector and others, including federal and state agencies, its plans to buy oil spill response equipment and the new responsibilities the act places on the private sector and the Coast Guard and if these responsibilities call for a shift in emphasis in Coast Guard oil spill response activities.

  16. Towards a standard framework to describe behaviours in the common-sloth (Bradypus variegatus Schinz, 1825): novel interactions data observed in distinct fragments of the Atlantic forest, Brazil.

    PubMed

    Silva, S M; Clozato, C L; Moraes-Barros, N; Morgante, J S

    2013-08-01

    The common three-toed sloth is a widespread species, but the location and the observation of its individuals are greatly hindered by its biological features. Their camouflaged pelage, its slow and quiet movements, and the strictly arboreal habits resulted in the publication of sparse, fragmented and not patterned information on the common sloth behaviour. Thus, herein we propose an updated standardized behavioural categories' framework to the study of the species. Furthermore we describe two never reported interaction behaviours: a probable mating / courtship ritual between male and female; and apparent recognition behaviour between two males. Finally we highlight the contribution of small-duration field works in this elusive species ethological study.

  17. Fragmentation of random trees

    NASA Astrophysics Data System (ADS)

    Kalay, Z.; Ben-Naim, E.

    2015-01-01

    We study fragmentation of a random recursive tree into a forest by repeated removal of nodes. The initial tree consists of N nodes and it is generated by sequential addition of nodes with each new node attaching to a randomly-selected existing node. As nodes are removed from the tree, one at a time, the tree dissolves into an ensemble of separate trees, namely, a forest. We study statistical properties of trees and nodes in this heterogeneous forest, and find that the fraction of remaining nodes m characterizes the system in the limit N\\to ∞ . We obtain analytically the size density {{φ }s} of trees of size s. The size density has power-law tail {{φ }s}˜ {{s}-α } with exponent α =1+\\frac{1}{m}. Therefore, the tail becomes steeper as further nodes are removed, and the fragmentation process is unusual in that exponent α increases continuously with time. We also extend our analysis to the case where nodes are added as well as removed, and obtain the asymptotic size density for growing trees.

  18. Fragmentation of random trees

    NASA Astrophysics Data System (ADS)

    Kalay, Ziya; Ben-Naim, Eli

    2015-03-01

    We investigate the fragmentation of a random recursive tree by repeated removal of nodes, resulting in a forest of disjoint trees. The initial tree is generated by sequentially attaching new nodes to randomly chosen existing nodes until the tree contains N nodes. As nodes are removed, one at a time, the tree dissolves into an ensemble of separate trees, namely a forest. We study the statistical properties of trees and nodes in this heterogeneous forest. In the limit N --> ∞ , we find that the system is characterized by a single parameter: the fraction of remaining nodes m. We obtain analytically the size density ϕs of trees of size s, which has a power-law tail ϕs ~s-α , with exponent α = 1 + 1 / m . Therefore, the tail becomes steeper as further nodes are removed, producing an unusual scaling exponent that increases continuously with time. Furthermore, we investigate the fragment size distribution in a growing tree, where nodes are added as well as removed, and find that the distribution for this case is much narrower.

  19. Influence of Elevated CO2 on the Fungal Community in a Coastal Scrub Oak Forest Soil Investigated with Terminal-Restriction Fragment Length Polymorphism Analysis

    PubMed Central

    Klamer, Morten; Roberts, Michael S.; Levine, Lanfang H.; Drake, Bert G.; Garland, Jay L.

    2002-01-01

    Sixteen open-top chambers (diameter, 3.66 m) were established in a scrub oak habitat in central Florida where vegetation was removed in a planned burn prior to chamber installation. Eight control chambers have been continuously exposed to ambient air and eight have been continuously exposed to elevated CO2 at twice-ambient concentration (∼700 ppm) for 5 years. Soil cores were collected from each chamber to examine the influence of elevated atmospheric CO2 on the fungal community in different soil fractions. Each soil sample was physically fractionated into bulk soil, rhizosphere soil, and roots for separate analyses. Changes in relative fungal biomass were estimated by the ergosterol technique. In the bulk soil and root fractions, a significantly increased level of ergosterol was detected in the elevated CO2 treatments relative to ambient controls. Fungal community composition was determined by terminal-restriction fragment length polymorphism (T-RFLP) analysis of the internal transcribed spacer (ITS) region. The specificities of different ITS primer sets were evaluated against plant and fungal species isolated from the experimental site. Changes in community composition were assessed by principal component analyses of T-RFLP profiles resolved by capillary electrophoresis. Fungal species richness, defined by the total number of terminal restriction fragments, was not significantly affected by either CO2 treatment or soil fraction. PMID:12200289

  20. California Coast

    Atmospheric Science Data Center

    2014-05-15

    ... of the San Joaquin valley. Santa Catalina and San Clemente Islands, warmed by the morning sun, are visible through the marine stratus ... bank is San Nicolas Island, and further up the coast are the Channel Islands. The Los Angeles basin is just south of center; San Diego is at ...

  1. Species–fragmented area relationship

    PubMed Central

    Hanski, Ilkka; Zurita, Gustavo A.; Bellocq, M. Isabel; Rybicki, Joel

    2013-01-01

    The species–area relationship (SAR) gives a quantitative description of the increasing number of species in a community with increasing area of habitat. In conservation, SARs have been used to predict the number of extinctions when the area of habitat is reduced. Such predictions are most needed for landscapes rather than for individual habitat fragments, but SAR-based predictions of extinctions for landscapes with highly fragmented habitat are likely to be biased because SAR assumes contiguous habitat. In reality, habitat loss is typically accompanied by habitat fragmentation. To quantify the effect of fragmentation in addition to the effect of habitat loss on the number of species, we extend the power-law SAR to the species–fragmented area relationship. This model unites the single-species metapopulation theory with the multispecies SAR for communities. We demonstrate with a realistic simulation model and with empirical data for forest-inhabiting subtropical birds that the species–fragmented area relationship gives a far superior prediction than SAR of the number of species in fragmented landscapes. The results demonstrate that for communities of species that are not well adapted to live in fragmented landscapes, the conventional SAR underestimates the number of extinctions for landscapes in which little habitat remains and it is highly fragmented. PMID:23858440

  2. Chameleon fragmentation

    SciTech Connect

    Brax, Philippe

    2014-02-01

    A scalar field dark energy candidate could couple to ordinary matter and photons, enabling its detection in laboratory experiments. Here we study the quantum properties of the chameleon field, one such dark energy candidate, in an ''afterglow'' experiment designed to produce, trap, and detect chameleon particles. In particular, we investigate the possible fragmentation of a beam of chameleon particles into multiple particle states due to the highly non-linear interaction terms in the chameleon Lagrangian. Fragmentation could weaken the constraints of an afterglow experiment by reducing the energy of the regenerated photons, but this energy reduction also provides a unique signature which could be detected by a properly-designed experiment. We show that constraints from the CHASE experiment are essentially unaffected by fragmentation for φ{sup 4} and 1/φ potentials, but are weakened for steeper potentials, and we discuss possible future afterglow experiments.

  3. Slow death for a swamp forest: Implications of salinity, infrastructure and their interactions for ecosystems in transition along North Carolina's estuarine coast

    NASA Astrophysics Data System (ADS)

    Moody, A.; Emanuel, R. E.

    2015-12-01

    Freshwater-dependent ecosystems of coastal North Carolina have been altered by humans over many centuries, mainly by draining these ecosystems to facilitate forestry and farming operations. In recent decades the quickening pace of sea level rise and infrequent but large coastal storms have exposed these ecosystems to additional pressures associated with the intrusion of brackish and salty water. Infrastructure, including roadbeds, levees, and other water management structures add additional complexity to this system by acting as either exacerbating or mitigating factors depending on time and location. This study investigates the dynamics of surface water and salinity in a critically stressed, freshwater swamp forest at Goose Creek State Park in coastal North Carolina. We evaluate temporal patterns of surface water elevation and salinity following a major inundation event (Hurricane Irene, 2011) at locations both upstream and downstream of an earthen roadbed that bisects the wetland. Results suggest that climatic conditions together with poor drainage through the roadbed caused harmful salinity levels to persist in the wetland for nearly a year following the hurricane, yet the potential also exists for the roadbed to protect the wetland from less extreme exposures to saltwater. This case study illustrates one facet of a complex, coupled natural-human system that is currently being reshaped by climate change. The work has implications for larger efforts to understand and assess the vulnerability of low-lying coastal regions to sea level rise and the preceding salinization.

  4. Thelephora versatilis and Thelephora pseudoversatilis: two new cryptic species with polymorphic basidiomes inhabiting tropical deciduous and sub-perennial forests of the Mexican Pacific coast.

    PubMed

    Ramírez-López, Itzel; Villegas-Ríos, Margarita; Salas-Lizana, Rodolfo; Garibay-Orijel, Roberto; Alvarez-Manjarrez, Julieta

    2015-01-01

    Thelephora is a genus of ectomycorrhizal basidiomycetes with basidiomes of varied shape which has been poorly studied in tropical ecosystems. In this paper, we present Thelephora versatilis and Thelephora pseudoversatilis, two new species collected in the same localities of deciduous and sub-perennial tropical forests of Jalisco, Mexico. Basidiomes of both species are brownish gray to violet brown with clavarioid-mesopodal, sub-resupinate or completely resupinate growth forms. In turn, phylogenetic analyses using nrDNA ITS sequences showed that these species are not closed related, nevertheless they are part of a well-supported clade conformed by several species of Thelephora, Tomentella and some undescribed Thelephorales. Morphological segregation of these species was attained by analyzing spore and hyphae characters using a wide sample. Significant statistical differences between the new species were observed regarding spore size, spine size and context hyphae width. This work exemplifies the relevance of integrating both morphological and molecular data, as well of the use of an appropriate sample size in order to discriminate among morphological cryptic species.

  5. Coast Guard

    SciTech Connect

    Not Available

    1991-06-01

    This paper reports that about 16,000 oil spills involving the release of more than 46 million gallons of oil took place in U.S. navigable waters in 1988; spills at water-front facilities, where vessels load and unload oil, accounted for about half of the oil spilled. While the Coast Guard acknowledges its responsibility for regulating and inspecting waterfront facilities, it efforts in this area have fallen short because it has not been inspecting portions of intrafacility pipes that transport oil between docks and storage tanks. Water pollution and noncompliance with federal oil pollution prevention regulations continue to be high at waterfront facilities. Yet the Coast Guard cannot determine how effective its inspection program has been in reducing the risk of oil spills because information on program results, such as the types, severity, and frequency of deficiencies found by inspectors, is not compiled an linked with information on the causes of oil spills found by investigators. Until the Coast Guard collects this type of information, it will not be in a position to establish measurable goals.

  6. Transforming Pinus pinaster forest to recreation site: preliminary effects on LAI, some forest floor, and soil properties.

    PubMed

    Öztürk, Melih; Bolat, İlyas

    2014-04-01

    This study investigates the effects of forest transformation into recreation site. A fragment of a Pinus pinaster plantation forest was transferred to a recreation site in the city of Bartın located close to the Black Sea coast of northwestern Turkey. During the transformation, some of the trees were selectively removed from the forest to generate more open spaces for the recreationists. As a result, Leaf Area Index (LAI) decreased by 0.20 (about 11%). Additionally, roads and pathways were introduced into the site together with some recreational equipment sealing parts of the soil surface. Consequently, forest environment was altered with a semi-natural landscape within the recreation site. The purpose of this study is to assess the effects of forest transformation into recreation site particularly in terms of the LAI parameter, forest floor, and soil properties. Preliminary monitoring results indicate that forest floor biomass is reduced by 26% in the recreation site compared to the control site. Soil temperature is increased by 15% in the recreation site where selective removal of trees expanded the gaps allowing more light transmission. On the other hand, the soil bulk density which is an indicator of soil compaction is unexpectedly slightly lower in the recreation site. Organic carbon (C(org)) and total nitrogen (N(total)) together with the other physical and chemical parameter values indicate that forest floor and soil have not been exposed to much disturbance. However, subsequent removal of trees that would threaten the vegetation, forest floor, and soil should not be allowed. The activities of the recreationists are to be concentrated on the paved spaces rather than soil surfaces. Furthermore, long-term monitoring and management is necessary for both the observation and conservation of the site.

  7. Fragmentation Processes

    NASA Astrophysics Data System (ADS)

    Whelan, Colm T.

    2012-12-01

    Preface; 1. Direct and resonant double-photoionization: from atoms to solids L. Avaldi and G. Stefani; 2. The application of propagation exterior complex scaling to atomic collisions P. L. Bartlett and A. T. Stelbovics; 3. Fragmentation of molecular-ion beams in intense ultra-short laser pulses I. Ben-Itzhak; 4. Atoms with one and two active electrons in strong laser fields I. A. Ivanov and A. S. Kheifets; 5. Experimental aspects of ionization studies by positron and positronium impact G. Laricchia, D. A. Cooke, Á. Kövér and S. J. Brawley; 6. (e,2e) spectroscopy using fragmentation processes J. Lower, M. Yamazaki and M. Takahashi; 7. A coupled pseudostate approach to the calculation of ion-atom fragmentation processes M. McGovern, H. R. J. Walters and C. T. Whelan; 8. Electron Impact Ionization using (e,2e) coincidence techniques from threshold to intermediate energies A. J. Murray; 9. (e,2e) processes on atomic inner shells C. T. Whelan; 10. Spin resolved atomic (e,2e) processes J. Lower and C. T. Whelan; Index.

  8. Coasts in Crisis

    SciTech Connect

    Hinrichsen, D.

    1996-11-01

    Coastal areas are staggering under an onslaught of human activity. We are presently in the process of destroying 70 percent of the world`s 600,000 square kilometers of coral reefs, an ecosystem containing some 200,000 different species and rivaling tropical rain forests in biodiversity. A combination of pollution, habitat destruction, and gross overfishing has led to the collapse of major fisheries and paved the way for malnutrition and disease in regions where people fish for subsistence. Globally, little is being done to manage the crisis of our coasts. Management strategies, if they exist at all, often deal with economic development along a wafer-thin strip of coastal land. Resource degradation is ignored, and watershed management is mostly rhetoric. Although some 55 countries have drawn up coastal management plans, only a handful have been properly implemented. Coasts must be managed in an integrated manner that takes into account the full range of human activities. Initiating this process is costly, time-consuming, and difficult. Yet we have more than three decades of accumulated experience to draw on.

  9. Effect of multi-temporal forest cover change trajectories on forest plant diversity

    EPA Science Inventory

    One of the principal tenets of landscape ecology is that forest loss and fragmentation negatively affects biodiversity. However, historical fluctuations in forest cover resulting from repeated cycles of deforestation and reforestation are likely important in influencing patterns ...

  10. Importance of riparian remnants for frog species diversity in a highly fragmented rainforest

    PubMed Central

    Rodríguez-Mendoza, Clara; Pineda, Eduardo

    2010-01-01

    Tropical forests undergo continuous transformation to other land uses, resulting in landscapes typified by forest fragments surrounded by anthropogenic habitats. Small forest fragments, specifically strip-shaped remnants flanking streams (referred to as riparian remnants), can be particularly important for the maintenance and conservation of biodiversity within highly fragmented forests. We compared frog species diversity between riparian remnants, other forest fragments and cattle pastures in a tropical landscape in Los Tuxtlas, Mexico. We found similar species richness in the three habitats studied and a similar assemblage structure between riparian remnants and forest fragments, although species composition differed by 50 per cent. Frog abundance was halved in riparian remnants compared with forest fragments, but was twice that found in pastures. Our results suggest that riparian remnants play an important role in maintaining a portion of frog species diversity in a highly fragmented forest, particularly during environmentally stressful (hot and dry) periods. In this regard, however, the role of riparian remnants is complementary, rather than substitutive, with respect to the function of other forest fragments within the fragmented forest. PMID:20554561

  11. Fractal forest: Fractal geometry and applications in forest science. Forest Service general technical report

    SciTech Connect

    Lorimer, N.D.; Haight, R.G.; Leary, R.A.

    1994-07-20

    Fractal geometry is a tool for describing and analyzing irregularity. Because most of what we measure in the forest is discontinuous, jagged, and fragmented, fractal geometry has potential for improving the precision of measurement and description. The study reviews the literature on fractal geometry and its applications to forest measurements.

  12. Year of the Coast.

    ERIC Educational Resources Information Center

    Jacobik, Gray; Lux, Gretchen

    1980-01-01

    President Carter has designated 1980 as the "Year of the Coast" through the efforts of a coalition known as the Coast Alliance. The Coast Alliance will alert people to changes along the coastline, and the need for public participation in the decisions which govern the use and abuse of the coastline. (DS)

  13. Forest Management.

    ERIC Educational Resources Information Center

    Weicherding, Patrick J.; And Others

    This bulletin deals with forest management and provides an overview of forestry for the non-professional. The bulletin is divided into six sections: (1) What Is Forestry Management?; (2) How Is the Forest Measured?; (3) What Is Forest Protection?; (4) How Is the Forest Harvested?; (5) What Is Forest Regeneration?; and (6) What Is Forest…

  14. Forest management is associated with physiological stress in an old-growth forest passerine.

    PubMed Central

    Suorsa, Petri; Huhta, Esa; Nikula, Ari; Nikinmaa, Mikko; Jäntti, Ari; Helle, Heikki; Hakkarainen, Harri

    2003-01-01

    We investigated how physiological stress in an area-sensitive old-growth forest passerine, the Eurasian treecreeper (Certhia familiaris), is associated with forest fragmentation and forest structure. We found evidence that the concentrations of plasma corticosterone in chicks were higher under poor food supply in dense, young forests than in sparse, old forests. In addition, nestlings in large forest patches had lower corticosterone levels and a better body condition than in small forest patches. In general, corticosterone levels were negatively related to body condition and survival. We also found a decrease in corticosterone levels within the breeding season, which may have been a result of an increase in food supply from the first to the second broods. Our results suggest that forest fragmentation may decrease the fitness of free-living individual treecreepers. PMID:12803912

  15. A tale of two storms: Surges and sediment deposition from Hurricanes Andrew and Wilma in Florida’s southwest coast mangrove forests: Chapter 6G in Science and the storms-the USGS response to the hurricanes of 2005

    USGS Publications Warehouse

    Smith, Thomas J.; Anderson, Gordon H.; Tiling, Ginger

    2007-01-01

    Hurricanes can be very different from each other. Here we examine the impacts that two hurricanes, Andrew and Wilma, had in terms of storm surge and sediment deposition on the southwest coast of Florida. Although Wilma was the weaker storm, it had the greater impact. Wilma had the higher storm surge over a larger area and deposited more sediment than did Andrew. This effect was most likely due to the size of Wilma's eye, which was four times larger than that of Andrew.

  16. Parton fragmentation functions

    NASA Astrophysics Data System (ADS)

    Metz, A.; Vossen, A.

    2016-11-01

    The field of fragmentation functions of light quarks and gluons is reviewed. In addition to integrated fragmentation functions, attention is paid to the dependence of fragmentation functions on transverse momenta and on polarization degrees of freedom. Higher-twist and di-hadron fragmentation functions are considered as well. Moreover, the review covers both theoretical and experimental developments in hadron production in electron-positron annihilation, deep-inelastic lepton-nucleon scattering, and proton-proton collisions.

  17. Fragmentation Analysis - Fundamental Processes

    DTIC Science & Technology

    Wausau quartzite and anorthosite of 3.0 to 3.5 inch size were fragmented in this device. An analysis of the fragment distribution results of the drop...disc-shaped specimens of Wausau quartzite, anorthosite , and Felch marble were then fragmented with the impact pendulum device. Computer programs were

  18. Selectable fragmentation warhead

    DOEpatents

    Bryan, Courtney S.; Paisley, Dennis L.; Montoya, Nelson I.; Stahl, David B.

    1993-01-01

    A selectable fragmentation warhead capable of producing a predetermined number of fragments from a metal plate, and accelerating the fragments toward a target. A first explosive located adjacent to the plate is detonated at selected number of points by laser-driven slapper detonators. In one embodiment, a smoother-disk and a second explosive, located adjacent to the first explosive, serve to increase acceleration of the fragments toward a target. The ability to produce a selected number of fragments allows for effective destruction of a chosen target.

  19. Universality of fragment shapes

    PubMed Central

    Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

    2015-01-01

    The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism. PMID:25772300

  20. Universality of fragment shapes

    NASA Astrophysics Data System (ADS)

    Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

    2015-03-01

    The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism.

  1. Fragmentation of habitats used by neotropical migratory birds in Southern Appalachians and the neotropics

    SciTech Connect

    Pearson, S.M.; Dale, V.H.; Offerman, H.L. |

    1993-12-31

    Recent declines in North American breeding populations have sparked great concern over the effects of habitat fragmentation. Neotropical migrant birds use and are influenced by two biomes during a single life span. Yet assessment of the relative importance of changes in tropical wintering areas versus temperate breeding areas is complicated by regional variation in rates and extent of habitat change. Landscape-level measurements of forest fragmentation derived from remotely-sensed data provide a means to compare the patterns of habitat modification on the wintering and breeding grounds of migrant birds. This study quantifies patterns of forest fragmentation in the Southern Appalachian Mountains and tropical Amazon and relates these patterns to the resource needs of neotropical migrant birds. Study sites were selected from remotely-sensed images to represent a range of forest fragmentation (highly fragmented landscape to continuous forest).

  2. Fragmentation properties of metals

    SciTech Connect

    Grady, D.E.; Kipp, M.E.

    1996-06-01

    In the present study we are developing an experimental fracture material property test method specific to dynamic fragmentation. Spherical test samples of the metals of interest are subjected to controlled impulsive stress loads by acceleration to high velocities with a light-gas launcher facility and subsequent normal impact on thin plates. Motion, deformation and fragmentation of the test samples are diagnosed with multiple flash radiography methods. The impact plate materials are selected to be transparent to the x-ray method so that only test metal material is imaged. Through a systematic series of such tests, both strain-to-failure and fragmentation resistance properties are determined through this experimental method. Fragmentation property data for several steels, copper, aluminum, tantalum and titanium have been obtained to date. Aspects of the dynamic data have been analyzed with computational methods to achieve a better understanding of the processes leading to failure and fragmentation, and to test an existing computational fragmentation model.

  3. Effects of habitat fragmentation and degradation on flocks of African ant-following birds.

    PubMed

    Peters, Marcell K; Likare, Smith; Kraemer, Manfred

    2008-06-01

    Tropical rain forests are rapidly cleared, fragmented, and degraded in sub-Saharan Africa; however, little is known about the response of species and even of key ecological groups to these processes. One of the most intriguing (but often neglected) ecological phenomena in African rain forests is the interaction between swarm-raiding army ants and ant-following birds. Similar to their well-known Neotropical representatives, ant-following birds in Africa track the massive swarm raids of army ants and feed on arthropods flushed by the ants. In this study we analyzed the effect of habitat fragmentation and degradation of a mid-altitude Congo-Guinean rain forest in western Kenya on the structure of ant-following bird flocks. Significant numbers of swarm raids were located in all forest fragments and in both undegraded and degraded forest. Fifty-six different species of birds followed army ant raids, forming bird flocks of one to 15 species. We quantitatively differentiated the bird community into five species of specialized ant-followers and 51 species of opportunistic ant-followers. Species richness and size of bird flocks decreased with decreasing size of forest fragments and was higher in undegraded than in degraded habitat. This was caused by the decrease of the species richness and number of specialized ant-followers at swarms, while the group of opportunistic ant-followers was affected little by habitat fragmentation and degradation. The composition of bird flocks was more variable in small fragments and degraded forest, compared to undegraded habitat in large fragments. The effect of habitat fragmentation on flock structure was best explained by the strong decline of the abundance of specialized ant-followers in small forest fragments. To conserve the association of army ants and ant-following birds in its natural state, vast areas of unfragmented and undegraded tropical rain forest are necessary.

  4. Oceans and Coasts

    EPA Pesticide Factsheets

    An overview of EPA’s oceans, coasts, estuaries and beaches programs and the regulatory (permits/rules) and non-regulatory approaches for managing their associated environmental issues, such as water pollution and climate change.

  5. Methane Emissions from Upland Forests

    NASA Astrophysics Data System (ADS)

    Megonigal, Patrick; Pitz, Scott; Wang, Zhi-Ping

    2016-04-01

    Global budgets ascribe 4-10% of atmospheric methane sinks to upland soils and assume that soils are the sole surface for methane exchange between upland forests and the atmosphere. The dogma that upland forests are uniformly atmospheric methane sinks was challenged a decade ago by the discovery of abiotic methane production from plant tissue. Subsequently a variety of relatively cryptic microbial and non-microbial methane sources have been proposed that have the potential to emit methane in upland forests. Despite the accumulating evidence of potential methane sources, there are few data demonstrating actual emissions of methane from a plant surface in an upland forest. We report direct observations of methane emissions from upland tree stems in two temperate forests. Stem methane emissions were observed from several tree species that dominate a forest located on the mid-Atlantic coast of North America (Maryland, USA). Stem emissions occurred throughout the growing season while soils adjacent to the trees simultaneously consumed methane. Scaling fluxes by stem surface area suggested the forest was a net methane source during a wet period in June, and that stem emissions offset 5% of the soil methane sink on an annual basis. High frequency measurements revealed diurnal cycles in stem methane emission rates, pointing to soils as the methane source and transpiration as the most likely pathway for gas transport. Similar observations were made in an upland forest in Beijing, China. However, in this case the evidence suggested the methane was not produced in soils, but in the heartwood by microbial or non-microbial processes. These data challenge the concept that forests are uniform sinks of methane, and suggest that upland forests are smaller methane sinks than previously estimated due to stem emissions. Tree emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration.

  6. Forest Resources

    SciTech Connect

    2016-06-01

    Forest biomass is an abundant biomass feedstock that complements the conventional forest use of wood for paper and wood materials. It may be utilized for bioenergy production, such as heat and electricity, as well as for biofuels and a variety of bioproducts, such as industrial chemicals, textiles, and other renewable materials. The resources within the 2016 Billion-Ton Report include primary forest resources, which are taken directly from timberland-only forests, removed from the land, and taken to the roadside.

  7. Fragments and Coherence

    ERIC Educational Resources Information Center

    Watson, Anne

    2008-01-01

    Can teachers contact the inner coherence of mathematics while working in a context fragmented by always-new objectives, criteria, and initiatives? How, more importantly, can learners experience the inner coherence of mathematics while working in a context fragmented by testing, modular curricular, short-term learning objectives, and lessons that…

  8. Fragment Hazard Investigation Program

    DTIC Science & Technology

    1978-10-01

    53 Ballistic Density (k) ............................................. 53 Ejection A ngle (a...54 Ejection Velocity (V) ................................................. 54 DEVELOPMENT OF EMPIRICAL RELATION...5S 54 Fragment Weight Versus Gamma for Test QD-155-08 ......................... 56 55 Fragment Range Versus Ejection Angle as a Function of

  9. Fragmentation of fullerenes

    NASA Astrophysics Data System (ADS)

    Chancey, Ryan T.; Oddershede, Lene; Harris, Frank E.; Sabin, John R.

    2003-04-01

    We have performed classical molecular-dynamics simulations of the fragmentation collisions of neutral fullerenes (C24, C60, C100, and C240) with a hard wall. The interactions between the carbon atoms are modeled by a Tersoff potential and the position of each carbon atom at each time step is calculated using a sixth-order predictor-corrector method. The statistical distribution of the fragments depends on impact energy. At low energies, the fragment distribution appears symmetric, with both the large and small fragment distributions well fitted by an exponential function of the same exponent, the value of which decreases with impact energy. At intermediate energies, the distribution of the smallest fragments can be fitted equally well by a power law or an exponential function. At high impact energies, the entire fragmentation pattern is well described by a single exponential function, the exponent increasing with energy. The observed tendencies in fragment distributions as well as the obtained exponents are in agreement with experimental observations. The fragmentation behavior of the four investigated fullerenes is very similar, and it is noted that C60 appears to be the most stable.

  10. Changes in Orchid Bee Communities Across Forest-Agroecosystem Boundaries in Brazilian Atlantic Forest Landscapes.

    PubMed

    De Aguiar, Willian Moura; Sofia, Silvia H; Melo, Gabriel A R; Gaglianone, Maria Cristina

    2015-12-01

    Deforestation has dramatically reduced the extent of Atlantic Forest cover in Brazil. Orchid bees are key pollinators in neotropical forest, and many species are sensitive to anthropogenic interference. In this sense understanding the matrix permeability for these bees is important for maintaining genetic diversity and pollination services. Our main objective was to assess whether the composition, abundance, and diversity of orchid bees in matrices differed from those in Atlantic forest. To do this we sampled orchid bees at 4-mo intervals from 2007 to 2009 in remnants of Atlantic Forest, and in the surrounding pasture and eucalyptus matrices. The abundance, richness, and diversity of orchid bees diminished significantly from the forest fragment toward the matrix points in the eucalyptus and pasture. Some common or intermediate species in the forest areas, such as Eulaema cingulata (F.) and Euglossa fimbriata Moure, respectively, become rare species in the matrices. Our results show that the orchid bee community is affected by the matrices surrounding the forest fragments. They also suggest that connections between forest fragments need to be improved using friendly matrices that can provide more favorable conditions for bees and increase their dispersal between fragments.

  11. Prioritizing bottomland hardwood forest sites for protection and augmentation

    USGS Publications Warehouse

    Carter, J.; Biagas, J.

    2007-01-01

    Bottomland hardwood forest has been greatly diminished by conversion to agriculture. Less than 25% of the pre-Columbian bottomland hardwood forests remain in the southeastern United States. Because of the valuable ecological and hydrological functions performed by these forests, their conservation and restoration has been a high priority. Part of these restoration efforts has focused on developing tools that can be used for both assessments at the landscape level and policy implementation at the local level. The distribution of bottomland hardwood forests in the Cache and White River watersheds in eastern Arkansas were examined using existing GIS databases. Criteria were developed to select areas that should be conserved or augmented for wildlife habitat. Over 67% of the study area was classified as agriculture, with bottomland hardwood forest the next largest habitat class. The thickness of a forest fragment was defined as the radius of the largest circle that can be inscribed in a fragment. Thickness was used in three ways. First, individual forest fragments were identified and selected based on ecological function using criteria we established. Second, individual fragments that were too small to support interior species, but large enough that if moderately augmented they could recover that function, were identified and selected. These augmentable fragments were further prioritized by adjacency to habitat that might be suitable for reforestation, namely agriculture. Third, watersheds were prioritized for conservation and augmentation based on the size and distributions of forest fragment thickness and area within each watershed.

  12. Amount of Forest Edge at a 65 Hectare Scale

    EPA Pesticide Factsheets

    Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and ecological values. EDGE65 is the percent of forest that is classified as edge using a 65 ha scale. More information about these resources, including the variables used in this study, may be found here: https://edg.epa.gov/data/Public/ORD/NERL/ReVA/ReVA_Data.zip.

  13. Amount of Future Forest Edge at a 65 Hectare scale

    EPA Pesticide Factsheets

    Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and ecological values. EDGE65 is the percent of forest that is classified as edge using a 65 ha scale. More information about these resources, including the variables used in this study, may be found here: https://edg.epa.gov/data/Public/ORD/NERL/ReVA/ReVA_Data.zip.

  14. Amount of Forest Edge at a 2 Hectare Scale

    EPA Pesticide Factsheets

    Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and ecological values. EDGE2 is the percent of forest that is classified as edge using a 2 ha scale. More information about these resources, including the variables used in this study, may be found here: https://edg.epa.gov/data/Public/ORD/NERL/ReVA/ReVA_Data.zip.

  15. Amount of Future Forest Edge at a 2 Hectare Scale

    EPA Pesticide Factsheets

    Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and ecological values. EDGE2 is the percent of forest that is classified as edge using a 2 ha scale. More information about these resources, including the variables used in this study, may be found here: https://edg.epa.gov/data/Public/ORD/NERL/ReVA/ReVA_Data.zip.

  16. Opaque rock fragments

    SciTech Connect

    Abhijit, B.; Molinaroli, E.; Olsen, J.

    1987-05-01

    The authors describe a new, rare, but petrogenetically significant variety of rock fragments from Holocene detrital sediments. Approximately 50% of the opaque heavy mineral concentrates from Holocene siliciclastic sands are polymineralic-Fe-Ti oxide particles, i.e., they are opaque rock fragments. About 40% to 70% of these rock fragments show intergrowth of hm + il, mt + il, and mt + hm +/- il. Modal analysis of 23,282 opaque particles in 117 polished thin sections of granitic and metamorphic parent rocks and their daughter sands from semi-arid and humid climates show the following relative abundances. The data show that opaque rock fragments are more common in sands from igneous source rocks and that hm + il fragments are more durable. They assume that equilibrium conditions existed in parent rocks during the growth of these paired minerals, and that the Ti/Fe ratio did not change during oxidation of mt to hm. Geothermometric determinations using electron probe microanalysis of opaque rock fragments in sand samples from Lake Erie and the Adriatic Sea suggest that these rock fragments may have equilibrated at approximately 900/sup 0/ and 525/sup 0/C, respectively.

  17. Deforestation trends of tropical dry forests in central Brazil

    USGS Publications Warehouse

    Bianchi, Carlos A.; Haig, Susan M.

    2013-01-01

    Tropical dry forests are the most threatened forest type in the world yet a paucity of research about them stymies development of appropriate conservation actions. The Paranã River Basin has the most significant dry forest formations in the Cerrado biome of central Brazil and is threatened by intense land conversion to pastures and agriculture. We examined changes in Paranã River Basin deforestation rates and fragmentation across three time intervals that covered 31 yr using Landsat imagery. Our results indicated a 66.3 percent decrease in forest extent between 1977 and 2008, with an annual rate of forest cover change of 3.5 percent. Landscape metrics further indicated severe forest loss and fragmentation, resulting in an increase in the number of fragments and reduction in patch sizes. Forest fragments in flatlands have virtually disappeared and the only significant forest remnants are mostly found over limestone outcrops in the eastern part of the basin. If current patterns persist, we project that these forests will likely disappear within 25 yr. These patterns may be reversed with creation of protected areas and involvement of local people to preserve small fragments that can be managed for restoration.

  18. Fragmentation of monoclonal antibodies

    PubMed Central

    Vlasak, Josef

    2011-01-01

    Fragmentation is a degradation pathway ubiquitously observed in proteins despite the remarkable stability of peptide bond; proteins differ only by how much and where cleavage occurs. The goal of this review is to summarize reports regarding the non-enzymatic fragmentation of the peptide backbone of monoclonal antibodies (mAbs). The sites in the polypeptide chain susceptible to fragmentation are determined by a multitude of factors. Insights are provided on the intimate chemical mechanisms that can make some bonds prone to cleavage due to the presence of specific side-chains. In addition to primary structure, the secondary, tertiary and quaternary structures have a significant impact in modulating the distribution of cleavage sites by altering local flexibility, accessibility to solvent or bringing in close proximity side chains that are remote in sequence. This review focuses on cleavage sites observed in the constant regions of mAbs, with special emphasis on hinge fragmentation. The mechanisms responsible for backbone cleavage are strongly dependent on pH and can be catalyzed by metals or radicals. The distribution of cleavage sites are different under acidic compared to basic conditions, with fragmentation rates exhibiting a minimum in the pH range 5–6; therefore, the overall fragmentation pattern observed for a mAb is a complex result of structural and solvent conditions. A critical review of the techniques used to monitor fragmentation is also presented; usually a compromise has to be made between a highly sensitive method with good fragment separation and the capability to identify the cleavage site. The effect of fragmentation on the function of a mAb must be evaluated on a case-by-case basis depending on whether cleavage sites are observed in the variable or constant regions, and on the mechanism of action of the molecule. PMID:21487244

  19. South Oregon Coast Reinforcement.

    SciTech Connect

    United States. Bonneville Power Administration.

    1998-05-01

    The Bonneville Power Administration is proposing to build a transmission line to reinforce electrical service to the southern coast of Oregon. This FYI outlines the proposal, tells how one can learn more, and how one can share ideas and opinions. The project will reinforce Oregon`s south coast area and provide the necessary transmission for Nucor Corporation to build a new steel mill in the Coos Bay/North Bend area. The proposed plant, which would use mostly recycled scrap metal, would produce rolled steel products. The plant would require a large amount of electrical power to run the furnace used in its steel-making process. In addition to the potential steel mill, electrical loads in the south Oregon coast area are expected to continue to grow.

  20. Universality in Fragmentation

    NASA Astrophysics Data System (ADS)

    Åström, J. A.; Holian, B. L.; Timonen, J.

    2000-04-01

    Fragmentation of a two-dimensional brittle solid by impact and ``explosion,'' and a fluid by ``explosion'' are all shown to become critical. The critical points appear at a nonzero impact velocity, and at infinite explosion duration, respectively. Within the critical regimes, the fragment-size distributions satisfy a scaling form qualitatively similar to that of the cluster-size distribution of percolation, but they belong to another universality class. Energy balance arguments give a correlation length exponent that is exactly one-half of its percolation value. A single crack dominates fragmentation in the slow-fracture limit, as expected.

  1. Fragmentation and hydration of tektites and microtektites

    USGS Publications Warehouse

    Glass, B.P.; Muenow, D.W.; Bohor, B.F.; Meeker, G.P.

    1997-01-01

    An examination of data collected over the last 30 years indicates that the percent of glass fragments vs. whole splash forms in the Cenozoic microtektite strewn fields increases towards the source crater (or source region). We propose that this is due to thermal stress produced when tektites and larger microtektites fall into water near the source crater while still relatively hot (>1150 ??C). We also find evidence (low major oxide totals, frothing when melted) for hydration of most of the North American tektite fragments and microtektites found in marine sediments. High-temperature mass spectrometry indicates that these tektite fragments and microtektites contain up to 3.8 wt% H2O. The H2O-release behavior during the high-temperature mass-spectrometric analysis, plus high Cl abundances (???0.05 wt%), indicate that the North. American tektite fragments and microtektites were hydrated in the marine environment (i.e., the H2O was not trapped solely on quenching from a melt). The younger Ivory Coast and Australasian microtektites do not exhibit much evidence of hydration (at least not in excess of 0.5 wt% H2O); this suggests that the degree of hydration increases with age. In addition, we find that some glass spherules (with 65 wt% SiO2 can undergo simple hydration in the marine environment, while impact glasses (with <65 wt% SiO2) can also undergo palagonitization.

  2. Fragmentation in Biaxial Tension

    SciTech Connect

    Campbell, G H; Archbold, G C; Hurricane, O A; Miller, P L

    2006-06-13

    We have carried out an experiment that places a ductile stainless steel in a state of biaxial tension at a high rate of strain. The loading of the ductile metal spherical cap is performed by the detonation of a high explosive layer with a conforming geometry to expand the metal radially outwards. Simulations of the loading and expansion of the metal predict strain rates that compare well with experimental observations. A high percentage of the HE loaded material was recovered through a soft capture process and characterization of the recovered fragments provided high quality data, including uniform strain prior to failure and fragment size. These data were used with a modified fragmentation model to determine a fragmentation energy.

  3. Unveiling a mechanism for species decline in fragmented habitats: fragmentation induced reduction in encounter rates

    PubMed Central

    Wosniack, M. E.; Santos, M. C.; Pie, M. R.; Marques, M. C. M.; Raposo, E. P.; Viswanathan, G. M.; da Luz, M. G. E.

    2014-01-01

    Several studies have reported that fragmentation (e.g. of anthropogenic origin) of habitats often leads to a decrease in the number of species in the region. An important mechanism causing this adverse ecological impact is the change in the encounter rates (i.e. the rates at which individuals meet other organisms of the same or different species). Yet, how fragmentation can change encounter rates is poorly understood. To gain insight into the problem, here we ask how landscape fragmentation affects encounter rates when all other relevant variables remain fixed. We present strong numerical evidence that fragmentation decreases search efficiencies thus encounter rates. What is surprising is that it falls even when the global average densities of interacting organisms are held constant. In other words, fragmentation per se can reduce encounter rates. As encounter rates are fundamental for biological interactions, it can explain part of the observed diminishing in animal biodiversity. Neglecting this effect may underestimate the negative outcomes of fragmentation. Partial deforestation and roads that cut through forests, for instance, might be responsible for far greater damage than thought. Preservation policies should take into account this previously overlooked scientific fact. PMID:24258156

  4. Forest Cover Estimation in Ireland Using Radar Remote Sensing: A Comparative Analysis of Forest Cover Assessment Methodologies.

    PubMed

    Devaney, John; Barrett, Brian; Barrett, Frank; Redmond, John; O Halloran, John

    2015-01-01

    Quantification of spatial and temporal changes in forest cover is an essential component of forest monitoring programs. Due to its cloud free capability, Synthetic Aperture Radar (SAR) is an ideal source of information on forest dynamics in countries with near-constant cloud-cover. However, few studies have investigated the use of SAR for forest cover estimation in landscapes with highly sparse and fragmented forest cover. In this study, the potential use of L-band SAR for forest cover estimation in two regions (Longford and Sligo) in Ireland is investigated and compared to forest cover estimates derived from three national (Forestry2010, Prime2, National Forest Inventory), one pan-European (Forest Map 2006) and one global forest cover (Global Forest Change) product. Two machine-learning approaches (Random Forests and Extremely Randomised Trees) are evaluated. Both Random Forests and Extremely Randomised Trees classification accuracies were high (98.1-98.5%), with differences between the two classifiers being minimal (<0.5%). Increasing levels of post classification filtering led to a decrease in estimated forest area and an increase in overall accuracy of SAR-derived forest cover maps. All forest cover products were evaluated using an independent validation dataset. For the Longford region, the highest overall accuracy was recorded with the Forestry2010 dataset (97.42%) whereas in Sligo, highest overall accuracy was obtained for the Prime2 dataset (97.43%), although accuracies of SAR-derived forest maps were comparable. Our findings indicate that spaceborne radar could aid inventories in regions with low levels of forest cover in fragmented landscapes. The reduced accuracies observed for the global and pan-continental forest cover maps in comparison to national and SAR-derived forest maps indicate that caution should be exercised when applying these datasets for national reporting.

  5. Forest Cover Estimation in Ireland Using Radar Remote Sensing: A Comparative Analysis of Forest Cover Assessment Methodologies

    PubMed Central

    Devaney, John; Barrett, Brian; Barrett, Frank; Redmond, John; O`Halloran, John

    2015-01-01

    Quantification of spatial and temporal changes in forest cover is an essential component of forest monitoring programs. Due to its cloud free capability, Synthetic Aperture Radar (SAR) is an ideal source of information on forest dynamics in countries with near-constant cloud-cover. However, few studies have investigated the use of SAR for forest cover estimation in landscapes with highly sparse and fragmented forest cover. In this study, the potential use of L-band SAR for forest cover estimation in two regions (Longford and Sligo) in Ireland is investigated and compared to forest cover estimates derived from three national (Forestry2010, Prime2, National Forest Inventory), one pan-European (Forest Map 2006) and one global forest cover (Global Forest Change) product. Two machine-learning approaches (Random Forests and Extremely Randomised Trees) are evaluated. Both Random Forests and Extremely Randomised Trees classification accuracies were high (98.1–98.5%), with differences between the two classifiers being minimal (<0.5%). Increasing levels of post classification filtering led to a decrease in estimated forest area and an increase in overall accuracy of SAR-derived forest cover maps. All forest cover products were evaluated using an independent validation dataset. For the Longford region, the highest overall accuracy was recorded with the Forestry2010 dataset (97.42%) whereas in Sligo, highest overall accuracy was obtained for the Prime2 dataset (97.43%), although accuracies of SAR-derived forest maps were comparable. Our findings indicate that spaceborne radar could aid inventories in regions with low levels of forest cover in fragmented landscapes. The reduced accuracies observed for the global and pan-continental forest cover maps in comparison to national and SAR-derived forest maps indicate that caution should be exercised when applying these datasets for national reporting. PMID:26262681

  6. Gulf Coast Wetlands

    Atmospheric Science Data Center

    2014-05-15

    article title:  Wetlands of the Gulf Coast     ... web of estuarine channels and extensive coastal wetlands that provide important habitat for fisheries. The city of New Orleans ... or below sea level. The city is protected by levees, but the wetlands which also function as a buffer from storm surges have been ...

  7. Coast Guard Firefighting Module

    NASA Technical Reports Server (NTRS)

    1977-01-01

    NASA and the U.S. Coast Guard are jointly developing a lightweight, helicopter-transportable, completely self-contained firefighting module for combating shipboard and dockside fires. The project draws upon NASA technology in high-capacity rocket engine pumps, lightweight materials and compact packaging.

  8. Northwest Coast Indian Art.

    ERIC Educational Resources Information Center

    Manning, Thomas; Knecht, Elizabeth

    The visual art forms of the Northwest Coast Indian Tribes of Alaska (Haida, Tlingit, and Tsimshian) share common distinctive design elements (formline, ovoid, U-form, and curvilinear shapes) which are referred to as the "Northern Style." Designs represent events or characters taken from the oral tradition of song and legend.…

  9. Post-Glacial Expansion and Population Genetic Divergence of Mangrove Species Avicennia germinans (L.) Stearn and Rhizophora mangle L. along the Mexican Coast

    PubMed Central

    Sandoval-Castro, Eduardo; Dodd, Richard S.; Riosmena-Rodríguez, Rafael; Enríquez-Paredes, Luis Manuel; Tovilla-Hernández, Cristian; López-Vivas, Juan Manuel; Aguilar-May, Bily; Muñiz-Salazar, Raquel

    2014-01-01

    Mangrove forests in the Gulf of California, Mexico represent the northernmost populations along the Pacific coast and thus they are likely to be source populations for colonization at higher latitudes as climate becomes more favorable. Today, these populations are relatively small and fragmented and prior research has indicated that they are poor in genetic diversity. Here we set out to investigate whether the low diversity in this region was a result of recent colonization, or fragmentation and genetic drift of once more extensive mangroves due to climatic changes in the recent past. By sampling the two major mangrove species, Rhizophora mangle and Avicennia germinans, along the Pacific and Atlantic coasts of Mexico, we set out to test whether concordant genetic signals could elucidate recent evolution of the ecosystem. Genetic diversity of both mangrove species showed a decreasing trend toward northern latitudes along the Pacific coast. The lowest levels of genetic diversity were found at the range limits around the Gulf of California and the outer Baja California peninsula. Lack of a strong spatial genetic structure in this area and recent northern gene flow in A. germinans suggest recent colonization by this species. On the other hand, lack of a signal of recent northern dispersal in R. mangle, despite the higher dispersal capability of this species, indicates a longer presence of populations, at least in the southern Gulf of California. We suggest that the longer history, together with higher genetic diversity of R. mangle at the range limits, likely provides a gene pool better able to colonize northwards under climate change than A. germinans. PMID:24699389

  10. Post-glacial expansion and population genetic divergence of mangrove species Avicennia germinans (L.) Stearn and Rhizophora mangle L. along the Mexican coast.

    PubMed

    Sandoval-Castro, Eduardo; Dodd, Richard S; Riosmena-Rodríguez, Rafael; Enríquez-Paredes, Luis Manuel; Tovilla-Hernández, Cristian; López-Vivas, Juan Manuel; Aguilar-May, Bily; Muñiz-Salazar, Raquel

    2014-01-01

    Mangrove forests in the Gulf of California, Mexico represent the northernmost populations along the Pacific coast and thus they are likely to be source populations for colonization at higher latitudes as climate becomes more favorable. Today, these populations are relatively small and fragmented and prior research has indicated that they are poor in genetic diversity. Here we set out to investigate whether the low diversity in this region was a result of recent colonization, or fragmentation and genetic drift of once more extensive mangroves due to climatic changes in the recent past. By sampling the two major mangrove species, Rhizophora mangle and Avicennia germinans, along the Pacific and Atlantic coasts of Mexico, we set out to test whether concordant genetic signals could elucidate recent evolution of the ecosystem. Genetic diversity of both mangrove species showed a decreasing trend toward northern latitudes along the Pacific coast. The lowest levels of genetic diversity were found at the range limits around the Gulf of California and the outer Baja California peninsula. Lack of a strong spatial genetic structure in this area and recent northern gene flow in A. germinans suggest recent colonization by this species. On the other hand, lack of a signal of recent northern dispersal in R. mangle, despite the higher dispersal capability of this species, indicates a longer presence of populations, at least in the southern Gulf of California. We suggest that the longer history, together with higher genetic diversity of R. mangle at the range limits, likely provides a gene pool better able to colonize northwards under climate change than A. germinans.

  11. Ranging, activity budget, and diet composition of red titi monkeys (Callicebus cupreus) in primary forest and forest edge.

    PubMed

    Kulp, Jenna; Heymann, Eckhard W

    2015-07-01

    Deforestation and fragmentation of tropical rainforests are increasingly creating forest edges and corresponding edge effects. Furthermore, primary forest is increasingly being replaced by secondary forest. The presence of high population densities of titi monkeys in fragmented and secondary forests suggests that they are capable of adapting to such habitat alterations. The aim of our study was to examine the ability of the red titi monkey (Callicebus cupreus) to adapt to forest edges and secondary forest. We compared home-range use, activity budgets, and diet composition in two groups of monkeys: one in primary forest and the other in primary forest with a long edge bordering secondary forest. The latter group avoided the secondary forest and used the edge in proportion to its availability. Groups did not differ in activity budgets but did show slight differences in diet composition. Taken together, our results suggest that there are no major effects of forest edges and secondary forest on red titi monkeys; however, given the relatively short study period, generalizations should be avoided until more comparative data become available. Furthermore, the age or successional stage of the secondary forest must be taken into consideration when drawing conclusions about its suitability as a primate habitat.

  12. Beyond the fragmentation threshold hypothesis: regime shifts in biodiversity across fragmented landscapes.

    PubMed

    Pardini, Renata; Bueno, Adriana de Arruda; Gardner, Toby A; Prado, Paulo Inácio; Metzger, Jean Paul

    2010-10-27

    Ecological systems are vulnerable to irreversible change when key system properties are pushed over thresholds, resulting in the loss of resilience and the precipitation of a regime shift. Perhaps the most important of such properties in human-modified landscapes is the total amount of remnant native vegetation. In a seminal study Andrén proposed the existence of a fragmentation threshold in the total amount of remnant vegetation, below which landscape-scale connectivity is eroded and local species richness and abundance become dependent on patch size. Despite the fact that species patch-area effects have been a mainstay of conservation science there has yet to be a robust empirical evaluation of this hypothesis. Here we present and test a new conceptual model describing the mechanisms and consequences of biodiversity change in fragmented landscapes, identifying the fragmentation threshold as a first step in a positive feedback mechanism that has the capacity to impair ecological resilience, and drive a regime shift in biodiversity. The model considers that local extinction risk is defined by patch size, and immigration rates by landscape vegetation cover, and that the recovery from local species losses depends upon the landscape species pool. Using a unique dataset on the distribution of non-volant small mammals across replicate landscapes in the Atlantic forest of Brazil, we found strong evidence for our model predictions--that patch-area effects are evident only at intermediate levels of total forest cover, where landscape diversity is still high and opportunities for enhancing biodiversity through local management are greatest. Furthermore, high levels of forest loss can push native biota through an extinction filter, and result in the abrupt, landscape-wide loss of forest-specialist taxa, ecological resilience and management effectiveness. The proposed model links hitherto distinct theoretical approaches within a single framework, providing a powerful tool

  13. IMPACT fragmentation model developments

    NASA Astrophysics Data System (ADS)

    Sorge, Marlon E.; Mains, Deanna L.

    2016-09-01

    The IMPACT fragmentation model has been used by The Aerospace Corporation for more than 25 years to analyze orbital altitude explosions and hypervelocity collisions. The model is semi-empirical, combining mass, energy and momentum conservation laws with empirically derived relationships for fragment characteristics such as number, mass, area-to-mass ratio, and spreading velocity as well as event energy distribution. Model results are used for several types of analysis including assessment of short-term risks to satellites from orbital altitude fragmentations, prediction of the long-term evolution of the orbital debris environment and forensic assessments of breakup events. A new version of IMPACT, version 6, has been completed and incorporates a number of advancements enabled by a multi-year long effort to characterize more than 11,000 debris fragments from more than three dozen historical on-orbit breakup events. These events involved a wide range of causes, energies, and fragmenting objects. Special focus was placed on the explosion model, as the majority of events examined were explosions. Revisions were made to the mass distribution used for explosion events, increasing the number of smaller fragments generated. The algorithm for modeling upper stage large fragment generation was updated. A momentum conserving asymmetric spreading velocity distribution algorithm was implemented to better represent sub-catastrophic events. An approach was developed for modeling sub-catastrophic explosions, those where the majority of the parent object remains intact, based on estimated event energy. Finally, significant modifications were made to the area-to-mass ratio distribution to incorporate the tendencies of different materials to fragment into different shapes. This ability enabled better matches between the observed area-to-mass ratios and those generated by the model. It also opened up additional possibilities for post-event analysis of breakups. The paper will discuss

  14. Maine coast winds

    SciTech Connect

    Avery, Richard

    2000-01-28

    The Maine Coast Winds Project was proposed for four possible turbine locations. Significant progress has been made at the prime location, with a lease-power purchase contract for ten years for the installation of turbine equipment having been obtained. Most of the site planning and permitting have been completed. It is expect that the turbine will be installed in early May. The other three locations are less suitable for the project, and new locations are being considered.

  15. CTFS-ForestGEO: a worldwide network monitoring forests in an era of global change.

    PubMed

    Anderson-Teixeira, Kristina J; Davies, Stuart J; Bennett, Amy C; Gonzalez-Akre, Erika B; Muller-Landau, Helene C; Wright, S Joseph; Abu Salim, Kamariah; Almeyda Zambrano, Angélica M; Alonso, Alfonso; Baltzer, Jennifer L; Basset, Yves; Bourg, Norman A; Broadbent, Eben N; Brockelman, Warren Y; Bunyavejchewin, Sarayudh; Burslem, David F R P; Butt, Nathalie; Cao, Min; Cardenas, Dairon; Chuyong, George B; Clay, Keith; Cordell, Susan; Dattaraja, Handanakere S; Deng, Xiaobao; Detto, Matteo; Du, Xiaojun; Duque, Alvaro; Erikson, David L; Ewango, Corneille E N; Fischer, Gunter A; Fletcher, Christine; Foster, Robin B; Giardina, Christian P; Gilbert, Gregory S; Gunatilleke, Nimal; Gunatilleke, Savitri; Hao, Zhanqing; Hargrove, William W; Hart, Terese B; Hau, Billy C H; He, Fangliang; Hoffman, Forrest M; Howe, Robert W; Hubbell, Stephen P; Inman-Narahari, Faith M; Jansen, Patrick A; Jiang, Mingxi; Johnson, Daniel J; Kanzaki, Mamoru; Kassim, Abdul Rahman; Kenfack, David; Kibet, Staline; Kinnaird, Margaret F; Korte, Lisa; Kral, Kamil; Kumar, Jitendra; Larson, Andrew J; Li, Yide; Li, Xiankun; Liu, Shirong; Lum, Shawn K Y; Lutz, James A; Ma, Keping; Maddalena, Damian M; Makana, Jean-Remy; Malhi, Yadvinder; Marthews, Toby; Mat Serudin, Rafizah; McMahon, Sean M; McShea, William J; Memiaghe, Hervé R; Mi, Xiangcheng; Mizuno, Takashi; Morecroft, Michael; Myers, Jonathan A; Novotny, Vojtech; de Oliveira, Alexandre A; Ong, Perry S; Orwig, David A; Ostertag, Rebecca; den Ouden, Jan; Parker, Geoffrey G; Phillips, Richard P; Sack, Lawren; Sainge, Moses N; Sang, Weiguo; Sri-Ngernyuang, Kriangsak; Sukumar, Raman; Sun, I-Fang; Sungpalee, Witchaphart; S