Individual variation changes dispersal distance and area requirements of a checkerspot butterfly
Authored by Leone M Brown, Elizabeth E Crone
Date Published: 2016
DOI: 10.1002/ecy.1216
Sponsors:
United States Department of Defense (DoD)
Platforms:
NetLogo
Model Documentation:
Other Narrative
Model Code URLs:
Model code not found
Abstract
Individual variation in movement can have important consequences for
spatial population dynamics. For instance, individual variation
increases leptokurtosis in dispersal distance, such that more
individuals move very short and very long distances relative to a
homogeneous population. We quantified individual variation in movement
of the Baltimore checkerspot butterfly (Euphydryas phaeton) to
investigate its importance for two conservation-related metrics: the
expected dispersal distance and the critical minimum patch size, or the
smallest area within which a population can persist based on loss due to
emigration. All movement parameters showed among-individual variation, with the greatest variation in move lengths and time spent resting.
Correlations in among-individual movement parameters indicated that some
butterflies were generally more mobile than others. We incorporated
empirically estimated movement and demographic parameters into two
individual-based models (IBMs), one with homogeneity in movement among
individuals, and one with heterogeneity in movement. As expected, individual variation in movement increased the leptokurtosis of lifetime
movement distance; the maximum difference in distance moved was
substantial (similar to 850m vs. similar to 5800m) and is likely of
significance for conservation. Individual variation also affected the
critical minimum patch size, but the difference (similar to 0.7ha vs.
similar to 0.5ha) is unlikely to be ecologically significant. Notably, populations with individual variation had higher growth rates in small
patches and lower growth rates in large patches, a logical consequence
of increased leptokurtosis. Individual variation in movement is fairly
straightforward to quantify using mixed effects models and is important
for spatial population dynamics, thus we encourage its inclusion in
studies of other systems.
Tags
Habitat restoration
Population-dynamics
Range expansion
Metabolic-rate
Metapopulation structure
Euphydryas-phaeton nymphalidae
Drury nymphalidae
Movement
behavior
Matrix habitats
Spatial
scale