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Human recreation has immediate and long-term impacts on wildlife, and exposure to recreational activities might be particularly high in urban systems. We investigated the relationship between human recreation and the spatial and temporal activity patterns of large mammals in an urban nature reserve. Data from remotely triggered infra-red cameras (1999-2001) were used to assess activity for bobcat, coyote, mule deer, humans, and domestic dogs along paths in the Nature Reserve of Orange County (NROC), California. Forty-nine camera sites established across the NROC yielded 16,722 images of humans, dogs, and our three target large mammal species during 4232 observation nights. Results suggest that bobcats, and to a lesser degree coyotes, exhibited both spatial and temporal displacement in response to human recreation. Bobcats were not only detected less frequently along trails with higher human activity, but also appeared to shift their daily activity patterns to become more nocturnal in high human use areas; negative associations between bobcat and human activity were particularly evident for bikers, hikers, and domestic dogs. In general, both bobcats and coyotes displayed a relatively wide range of activity levels at sites with low human use, but a lower and markedly restricted range of activity at those sites with the highest levels of recreation. Although we did not find a clear and consistent pattern of avoidance of human recreation by deer, the probability of detecting deer during the day was lower with increasing levels of human recreation. Future studies that experimentally investigate the impacts of recreationists on wildlife, as well as relate behavioral responses to survival and reproduction, will allow further insight of the effects of urban recreation on large mammal populations.  相似文献   
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Context

Habitat loss, especially within agriculture, can be a threat to biodiversity. However, biodiversity may respond slowly to habitat loss, taking time to undergo successional change following a disturbance. Despite the fact that historic processes often mediate current patterns of biodiversity, most studies focus only on contemporary factors.

Objectives

Our research examines how both contemporary and historic environmental factors impact current pollinator community similarity, or beta-diversity. We examine two hypotheses: H1) contemporary land-use predicts community similarity, but also that land-use history has long-lasting effects on beta-diversity; H2) the specific response to contemporary and historic environmental factors is explained by variation in pollinator species life-history traits.

Methods

We sampled 36 pollinator communities over a three-year period across cotton fields varying in historic and contemporary land-use. Using multiple regression on distance matrices (MRDM), we investigate correlations between community similarity and differences in contemporary and historic environmental factors.

Results

First, we show that increased time between sampling events and the loss of semi-natural habitat over a 19-year period led to decreased community similarity. Interestingly, neither geographic distance nor contemporary environmental factors contributed to similarity. Second, we show that much of the variation in community similarity is due to variation in pollinator species life-history traits, such as foraging ability and diet breadth.

Conclusions

Results indicate that land-use history has long-lasting effects on community composition, greater than effects exhibited by contemporary factors. These legacy effects are critical considerations for conservation as their omission may lead to overly optimistic assessments of biodiversity in recently disturbed habitats.
  相似文献   
3.
Landscape Ecology - Bees are the most important pollinators of crops worldwide. For most bees, patches of semi-natural habitat within or adjacent to crops can provide important nesting and food...  相似文献   
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