Johnson et al. Power laws are also used as scale-independent descriptors of the movement characteristics of beetles. They find that beetle movement patterns fall into several distinct scale ranges, being bordered on the upper end by a kind of home range. Thus beetle movement depends on intrinsic movement rules, landscape pattern, and the spatial and temporal scales of observation. Using percolation theory, fractal geometry and diffusion models, they are able to construct a fairly parsimonious model of the movement patterns of beetles over a range of scales and a variety of habitats.
Conclusions Describing the movement of organisms across landscapes is quite difficult.
One must consider the effects of spatial and temporal scales, landscape pattern, physiological organism movement constraints, and the intended use of the predictions or model when constructing models of organism movement. Diffusion models work well because they allow scientists to make quantitative predictions about the aggregate movement of organisms based on a few simple empirical observations. Fractal geometry and percolation theory are useful for quantifying heterogeneity in landscape patterns and animal movement patterns across scales, again with only a few simple observations. Work still needs to be done to make these models more robust for a broad range of organisms and situations. Return to table of contents Bibliography Andow, D. A., P. M. Kareiva, S. A. Levin, and A. Okubo.