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The relative effects of habitat loss, fragmentation, and degradation on population extinction
Citation:
Heinrichs, J., D. Bender, AND N. H. SCHUMAKER. The relative effects of habitat loss, fragmentation, and degradation on population extinction. Presented at 2010 US-IALE Twenty-fifth Anniversary Symposium, Athens, GA, April 05 - 09, 2010.
Impact/Purpose:
The most prominent conservation concerns are typically habitat loss and habitat fragmentation.
Description:
The most prominent conservation concerns are typically habitat loss and habitat fragmentation. The role of habitat degradation has received comparatively little attention. But research has shown that the quality of habitat patches can significantly influence wildlife population dynamics, suggesting that habitat degradation may be a key variable explaining population responses to landscape change and disturbance. We conducted a simulation modeling study to determine the relative influence of habitat quantity, fragmentation, and quality on regional population persistence. We adopted a life history strategy approach stratified by dispersal ability and resource requirements. Population dynamics were simulated in landscapes which varied in their degree of habitat loss, fragmentation, and habitat degradation according to a factorial design. Population dynamics were evaluated using a spatially-explicit individual-based computer simulation model. Landscape configurations ranged from contiguous to highly fragmented. The importance of habitat quantity, fragmentation, and quality for population persistence was evaluated using generalized linear models. For the most part, habitat amount and quality outweighed the influence of habitat fragmentation. Dramatic extinction thresholds were observed in scenarios that combined habitat loss and degradation, indicating that the interactive effects of these variables may greatly affect population persistence. The results also suggest that in some circumstances the population viability consequences of habitat loss might be effectively mitigated through improvements to habitat quality. While the current paradigm for conservation emphasizes the role of habitat fragmentation, our results demonstrate that habitat quality may at times be of greater importance.