Correlates of Amphibian Diversity in an Altered Landscape of Amazonian Ecuador

There is disagreement on the effects of logging and habitat alteration on amphibians and few studies have addressed this issue in tropical forests. I addressed whether the habitat variation associated with logging and agriculture is correlated with the species richness and community structure in an assemblage of amphibians in the Tropical Wet Forest life zone in Amazonian Ecuador. I evaluated 10 variables describing environmental variation and forest structure at 23 0.5‐ha sites and sampled amphibians using nocturnal visual searches of transects. Overall amphibian species richness increased weakly with distance to pasture but taxa differed in correlates of diversity. Species richness in the genus Eleutherodactylus increased markedly with distance to pasture. Eleutherodactylus species richness was highest at intermediate values of stand basal area, which contributed to my detecting only weak differences in species richness between primary and selectively logged sites. Overall, distance to pasture, basal area, and understory density explained much of the variation in Eleutherodactylus species richness. In contrast to Eleutherodactylus, species richness of hylid frogs was relatively greater in sites with low basal area, predominantly in selectively‐logged forest. Patterns of amphibian species richness poorly represented eleutherodactyline frogs because the absence of Eleutherodactylus from disturbed sites was sometimes masked by increasing richness of disturbance‐tolerant species. Canonical correspondence analysis indicated that species occurrence varied with measured environmental variation; some species distinctly prefer less‐disturbed forest. The generality of these patterns should be confirmed in additional studies. The results suggest that overall amphibian richness is not a good indicator of conservation value for disturbance‐sensitive eleutherodactylines, which are nocturnal, rare, and difficult to identify. Elutherodactylines in Tropical Wet Forest provide a good opportunity for the development of indicator relationships for the conservation of a disturbance‐sensitive assemblage. The mechanisms that result in the patterns of diversity described here are unknown and warrant further study. These observations, and the quantitative relationships developed here, suggest the use of empirical environment/diversity relationships for preliminary assessment of tropical amphibian diversity and in predicting the effects of forest management on disturbance‐sensitive species.