INTERSPECIFIC SPATIAL OVERLAP

Interspecific spatial overlap profiles are constructed for several pai rs of iguanid lizard species. The profiles depict the proportion of ac tivity points within the territories and home ranges of target lizards that are shared with individuals of other lizard species. Results sho w that within populations some individuals may incur little or no spat ial overlap from other lizard species, whereas others have high spatia l overlap. These patterns of overlap may be sustained through entire s easons of lizard activity. Profile shapes included distributions that were unimodal and strongly skewed, bimodal, and uniform with roughly e quivalent proportions of low, intermediate, and high overlaps. Spatial overlap profiles are idiosyncratic, neither characterizing a particul ar 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 populatio n level, but may include asymmetric effects targeted at specific indiv iduals. In addition, because spatial overlap profiles for a pair of sp ecies are variable, interactions cannot be characterized by the result s of an experimental manipulation conducted in just one habitat.