Concepts of vertebrate succession in terrestrial habitats are based mainly on studies of birds and mammals. To provide a broader understanding of vertebrate succession and the organization of species assemblage, we studied the development of a herpetofaunal assemblage in a reforestation project. We sampled herpetofauna monthly between February 2001 and March 2002 and between June and September 2003 in a reforested limestone valley, and compared the composition and structure of the species assemblage in this valley with three reference sites and a deforested valley in a limestone region of Puerto Rico. In the reforested valley, the increase in vegetation heterogeneity and the decrease in microclimate variability facilitated herpetofaunal succession. Species richness increased rapidly from three to eleven species in 13 mo, with predatory species colonizing the reforested valley by the end of the study. The trophic structure changed more slowly with the density of individuals of (1) arboreal species increasing with increased woody vegetation cover, and (2) predatory species increasing with increased prey density. The pattern of herpetofaunal succession can be described by an assembly rule that considers microclimate as an important controller for the development of the species assembly. We suggest that including microclimate in assembly rules can help us broaden our understanding of factors that determine vertebrate succession in terrestrial habitats.