Animal movement varies with resource availability, landscape configuration and body size: a conceptual model and empirical example
Animals must move to find food, shelter and mates, and escape predation and competition. Changes in landscape configuration and resource availability can disrupt natural movement, negatively impacting fitness and population persistence.
Here, we propose a conceptual model to better understand the interactive effects of landscape configuration, resource availability and body size on animal movement. We then apply this model to a field study of reptile movement in a fragmented farming landscape.
We radio-tracked dragons in a large rectangular remnant (with high tree cover) and a series of narrow linear remnants (low tree cover). Soil nutrients and beetle abundance (potential food) were higher in the linear remnants compared to the large rectangular remnant. Using 2301 tracking points from 59 individual × month combinations, we calculated activity area size and shape, daily movement rate and monthly displacement distance.
Activity area size and daily movement rate were lower in the linear remnants compared to the large rectangular remnant and increased with body size. Activity area linearity increased in linear remnants for larger animals only. Monthly displacement distance did not vary according to tree cover or body size.
Dragons reduced their movement in linear remnants that have higher resource availability. Larger animals were more affected by landscape configuration as the dimensions of their normal activity areas exceeded the typical widths of the linear remnants. Future studies of animal movement in production landscapes will benefit from incorporating measures of resource availability, body size and landscape configuration to test predictions derived from theory.
KeywordsBiodiversity conservation Habitat fragmentation Home range Land use change Movement ecology Spatial ecology
This research was generously funded by the Australian Academy of Science’s Margaret Middleton Fund Award and Deakin University’s Centre for Integrative Ecology. We gratefully acknowledge David and Bronwyn Heath for allowing us access to their property, and the National Parks and Wildlife Service for allowing us to work in Pulletop Nature Reserve. We thank Nick Porch and his assistants for sorting and counting the beetle collections, as well as the many volunteers who helped with fieldwork and two anonymous reviewers for their comments on an earlier version of this paper.
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