The risk of ignoring fear: underestimating the effects of habitat loss and fragmentation on biodiversity

摘要

Context Habitat loss and fragmentation threaten species not only through structural landscape changes and resource reduction, but also through modifications to species' interactions. In particular, the observed consequences of landscape changes for predator-prey interactions often lack a clear pattern, indicating a range of complex behavioral adaptations and interactions. One potentially important contributing factor shaping these consequences is perceived predation risk and hence fear, which is rarely explicitly addressed in studies on habitat modification. Objectives We investigated how fear changes prey community structures under habitat loss and fragmentation and identified habitat properties driving these changes. Methods We applied a spatially-explicit, individual-based model which simulates home range formation of a mammalian prey community based on food availability and perceived predation risk. With the model we predicted prey community structures under different landscape scenarios. Results Fear intensified the negative effects of habitat loss and fragmentation on prey communities, causing a non-proportional diversity loss of up to 30%. Shifts in community composition from large to small animals were reinforced. The highest prey diversity was supported in landscapes with non-fragmented safe areas. Our findings highlight the importance of fear in shaping prey community structures under conditions of landscape change. Conclusions Our modelling approach addresses the mechanisms that link individual space use with community structure. It reveals the key role played by the spatial distribution of safe patches in mitigating the negative effects of landscape changes. Thereby, it supports modern conservation efforts that go beyond single-species approaches by taking changes in community structure into account.