Life history changes in the eastern collared lizard in response to varying demographic phases and management policies

Abstract

AbstractBy 1980 eastern collared lizards (Crotaphutus collaris collaris) had experienced massive local extinction on glades (open, rocky areas imbedded in a woodland matrix) in the Ozarks, a highland region in central North America. Lizards were translocated to the Peck Ranch Conservation Area in Missouri on three restored glades starting in 1984, and went through three demographic phases: (1) an isolate phase with initial growth followed by decline in population size and no colonization of nearby glades; (2) a colonizing phase of high dispersal and population growth that started with the onset of prescribed woodland burning, and (3) a stable metapopulation phase. We used mark/recapture information on over 1500 lizards with high sample coverage to estimate life history parameters. Life history was homogeneous within each phase, but differed significantly between phases. Changes occurred in less than a generation, indicating plasticity in life history. The isolate phase was characterized by low juvenile survivorship, high adult survivorship, long generation times, an old age structure, and almost no dispersal. The colonization phase had increased yearling survival, decreased adult survival, shorter generation times, a younger age structure, and much dispersal. The stable metapopulation phase was intermediate between these two extremes. These transitions indicated trade‐offs among different life history parameters. These plastic life history attributes show that species cannot be regarded as static units, resulting in not a life history, but rather a set of feasible life histories. Ignoring this set of feasible life histories can result in poor conservation decisions.