Short-and long-term effects of fire and fire-induced vegetation cover on four lizard specieis in Amazonion Savannas.

Abstract

Ecological succession in tropical savannas is limited by seasonally predictable, but irregular fire, which consequently causes temporal variation in habitat quality for the fauna. Although fire may cause negligible or positive effects on animals occupying savannas, most short-term studies are based on a single temporal sampling snapshot, and long-term studies are rare. In this study, we sampled four lizard species in Amazonian savannas to test the effects of fire and fire-mediated vegetation cover on lizard densities at two temporal scales. In the short term, we use three sampling snapshots to test the effects of fire and vegetation cover on estimated lizard densities over the subsequent 1–5 years. In the long term, we test the cumulative effects of fire and changes in vegetation cover over 21 years on current lizard density differences. In the short term, we found some significant effects of fire and vegetation cover on lizard densities, usually consistent with foraging and thermoregulation modes. However, results varied widely among species and years, suggesting that firemediated ecological relationships depend on unknown, highly dynamic variables over time. In the long-term, the most significant effects of fire and vegetation cover show that variation in habitat quality may change density spatial structure, which does not necessarily imply temporal changes in lizard densities. Fire is a natural feature of savannas, and appears to have little impact on resident species of lizards that are adapted to seasonal and natural burning processes in these environments.