Organization of a taxonomically diverse lizard assemblage in Amazonian Ecuador

Abstract

Of 22 lizard species studied in eastern Ecuador, 21 were diurnal. Ten were active foragers and 12 were sit-and-wait foragers. Considerable variation existed in habitat and microhabitat distribution and body temperatures among species. Body size varied over an order of magnitude (20–270 mm snout–vent length). Most morphological (size-free) variation among species (77%) was accounted for by two principal component axes and appears tied to phylogeny. Prey size was correlated with lizard size and species were separated by prey size. Low overlaps in microhabitat, habitat, and prey type also separated species. Pseudocommunity analysis indicated structure in the consumer–resource matrix. In some comparisons, prey overlaps among species were greater within than between higher taxa, and closely related species tended to be found in similar habitat patches and microhabitats, suggesting that resource-use patterns are determined to some extent by phylogeny. Ecology, morphology, and phylogeny appear tied together in a complex manner, with resource partitioning contributing to maintenance of structure. Historical interactions among closely related species may have been important in determining which species within particular clades invaded and persisted within local assemblages in lowland forest.