Factors influencing tropical lizard reproduction vary by microhabitat but not forest type

Abstract

Abstract To understand mechanisms behind enigmatic declines of tropical reptiles, knowledge of species interactions and how they vary over space and time is important. Some tropical lizard population dynamics can be highly influenced by egg survival. Yet relatively few studies have examined relationships between lizard reproductive success and egg predators across forest and microhabitat types. In this study, we examined variation in probability of egg depredation, predatory ant abundance, prey availability, and the number of lizards and eggs encountered across four different forest types (abandoned agroforestry, abandoned plantation, secondary forest, and old-growth forest) and three microhabitats (buttress, fallen log, and leaf-litter) at La Selva Biological Station, Costa Rica. Based on previous studies, we made three hypotheses about how lizard egg abundance, egg survival, and predatory ant numbers would be related across microhabitat and forest type. Of these hypotheses, only one was supported: we found more lizard eggs in buttress and fallen log microhabitats than leaf-litter. We did not observe any differences in lizard reproduction or numbers of invertebrates by forest type alone. Based on patterns observed in this study, we suggest that future studies investigating tropical leaf-litter lizard declines focus on environmental variation at the microhabitat scale.