Tamaño poblacional, uso del hábitat y relaciones interespecíficas de Agalychnis spurrelli (anura: hylidae) en un bosque húmedo tropical remanente del noroccidente de Ecuador

Abstract

Throughout 2006 and 2007, at a small swamp in San Francisco del Cabo, northwestern Ecuador, monthly field expeditions were done to monitor a population of the leaf frog Agalychnis spurrelli with the following aims: (1) to determine population size and annual fluctuation; (2) to determine spatial distributional patterns and microhabitat resource partitioning; and (3) to analyze associations with other nocturnal frogs. We employed standardized sampling methods to study the population size, which included capture-recapture analysis using toe clip codes. In northwestern Ecuador, Agalychnis spurrelli presents highly effective population sizes, with local increments in relative density through rainy and breeding seasons, beginning in February. A low recapture rate was obtained and population size was projected between 1400 to 6000 individuals of Agalychnis spurrelli for Laguna del Diablo. Throughout the dry season this particular frog prefers the canopy of higher trees, descending only to low vegetation which occurs around the swamp when the breeding season begins. We obtained low rates in overlap and amplitude functional niche values, demonstrating a high level of specialization in resource partitioning in the habitat. Nine species of nocturnal anurans were identified around this body of water, among which, Hypsiboas rosenbergi and H. pellucens were the most similar species to A. spurrelli in resource use and spatial distribution at the swamp. The snake Leptodeira septentrionalis is its principal predator.