PATTERNS OF REPRODUCTION AND HABITAT USE IN AN ASSEMBLAGE OF NEOTROPICAL HYLID FROGS

We censused pond-breeding hylid frogs in northeastern Costa Rica weekl y for 15 months to describe patterns of reproduction, habitat use, and to establish baseline data on relative abundance for members of the a ssemblage. Reproduction in the Costa Rican assemblage was seasonal and occurred only during wet months. Some species called, but none reprod uced, during the dry season. Three species (Agalychnis callidryas, Hyl a ebraccata, and Scinax elaeochroa) accounted for more than 75% of the observations made during the study. The species overlapped broadly in time and space, but differed in substrate use and phenology. Two spec ies of leaf-breeding frogs (A. callidryas and A. saltator) used perche s that were significantly higher than those used by the other species. Some phenological differences were associated with different mating s trategies. Explosive breeders (Scinax elaeochroa and Smilisca baudinii ) were most common early in the wet seasons. Prolonged breeders (A. ca llidryas and H. ebraccata) were the most persistent members of this as semblage. Predation affects early and late life history stages of thes e hylids. Predation on arboreal egg masses by two snake species was ob served. Ctenid spiders preyed on recently metamorphosed frogs and smal l adults. Our weekly samples were pooled into 21-day periods so that w e could compare our results with those obtained for two communities of breeding anurans from South America. The patterns observed in the Cos ta Rican assemblage differed from those reported for South American po nd-breeding frogs, but in all three assemblages reproduction was assoc iated with wet periods.