Interspecific Spatial Overlap

Abstract

Interspecific spatial overlap profiles are constructed for several pairs of iguanid lizard species. The profiles depict the proportion of activity points within the territories and home ranges of target lizards that are shared with individuals of other lizard species. Results show that within populations some individuals may incur little or no spatial overlap from other lizard species, whereas others have high spatial overlap. These patterns of overlap may be sustained through entire seasons of lizard activity. Profile shapes included distributions that were unimodal and strongly skewed, bimodal, and uniform with roughly equivalent proportions of low, intermediate, and high overlaps. Spatial overlap profiles are idiosyncratic, neither characterizing a particular pair of lizard species, nor typifying a specific habitat type. The observations provide insight into the results of experimental studies that show weak or undetectable effects of competition at the population level, but may include asymmetric effects targeted at specific individuals. In addition, because spatial overlap profiles for a pair of species are variable, interactions cannot be characterized by the results of an experimental manipulation conducted in just one habitat.