Conservation biology: predicting birds' responses to forest fragmentation.

Center for Conservation Biology, Department of Biological Sciences, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA.
Current Biology (Impact Factor: 9.49). 11/2007; 17(19):R838-40. DOI: 10.1016/j.cub.2007.07.037
Source: PubMed

ABSTRACT Understanding species' ecological responses to habitat fragmentation is critical for biodiversity conservation, especially in tropical forests. A detailed recent study has shown that changes in the abundances of bird species following fragmentation may be dramatic and unpredictable.

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    ABSTRACT: Aim Few studies have attempted to assess the overall impact of fragmentation at the landscape scale. We quantify the impacts of fragmentation on plant diversity by assessing patterns of community composition in relation to a range of fragmentation measures.Location The investigation was undertaken in two regions of New Zealand – a relatively unfragmented area of lowland rain forest in south Westland and a highly fragmented montane forest on the eastern slopes of the Southern Alps.Methods We calculated an index of community similarity (Bray–Curtis) between forest plots we regarded as potentially affected by fragmentation and control forest plots located deep inside continuous forest areas. Using a multiple nonlinear regression technique that incorporates spatial autocorrelation effects, we analysed plant community composition in relation to measures of fragmentation at the patch and landscape levels. From the resulting regression equation, we predicted community composition for every forest pixel on land-cover maps of the study areas and used these maps to calculate a landscape-level estimate of compositional change, which we term ‘BioFrag’. BioFrag has a value of one if fragmentation has no detectable effect on communities within a landscape, and tends towards zero if fragmentation has a strong effect.Results We detected a weak, but significant, impact of fragmentation metrics operating at both the patch and landscape levels. Observed values of BioFrag ranged from 0.68 to 0.90, suggesting that patterns of fragmentation have medium to weak impacts on forest plant communities in New Zealand. BioFrag values varied in meaningful ways among landscapes and between the ground-cover and tree and shrub communities.Main conclusions BioFrag advances methods that describe spatial patterns of forest cover by incorporating the exact spatial patterns of observed species responses to fragmentation operating at multiple spatial scales. BioFrag can be applied to any landscape and ecological community across the globe and represents a significant step towards developing a biologically relevant, landscape-scale index of habitat fragmentation.
    Global Ecology and Biogeography. 04/2010; 19(5):741 - 754.
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    ABSTRACT: We evaluated the response of male Reeves's pheasants Syrmaticus reevesii to different forest edges in a fragmented forest landscape in central China using radio-telemetry. Our fieldwork was carried out from April 2000 to August 2003 in the Dongzhai National Nature Reserve within the Dabie Mountains, China. We identified four major types of forest edges: shrub, farmland, road and residential edge. The association of male Reeves's pheasants with these edges was non-random and varied by season, suggesting that land-cover and land-use patterns surrounding forest fragments could have variable effects on habitat use of Reeves's pheasants. Shrub edges were preferred by males in all seasons and male Reeves's pheasant seldom moved > 200 m from this type of edge. Pheasants tended to avoid farmland edges in summer, stayed within 100 m of the nearest road edges in spring and moved farther from residential edges with season shifts. Furthermore, edge use by male Reeves's pheasants also differed between winter and the other three seasons. Our data demonstrated the relationships between edge effects and the spatial distribution patterns of Reeves's pheasants, and suggested that landscape configuration, including juxtaposition of forest and shrubby vegetation, should be incorporated into management and conservation for addressing edge effects at landscape scales. We suggest monitoring the spatial responses of this species to different forest edges over a longer term and at a larger landscape scale.
    Wildlife Biology 05/2011; · 1.10 Impact Factor
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    ABSTRACT: Seed dispersing animals, ranging from small insects to large mammals, provide a crucial service for a large number of plant species worldwide. However, a decline in dispersers due to direct and indirect threats leads to disruptions of seed dispersal processes. As disperser species are differently susceptible to these threats, consequences for ecosystems are hard to predict. Impacts range from hampered regeneration of plant species to shifts in communities and a decline in ecosystem function. Here, we review these threats as well as expected consequences for communities and for the entire ecosystem. We further introduce options to protect dispersers and consider future research directions.
    Basic and Applied Ecology 01/2012; 13:109-115. · 2.70 Impact Factor

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