Effects of fire and cattle grazing on amphibians and lizards in northeastern Argentina (Humid Chaco)

Richness, diversity and abundance of amphibians and lizards were compared in four sites subjected to different fire and grazing regimes in Mburucuya National Park (Corrientes, Argentina). The surveys were performed using drift fence-pitfall traps randomly distributed in four sites subjected to the following prescribed fire and grazing regimes: (A) no fire or grazing for the last 12 years (control), (B) 3 years since the last prescribed fire, (C) annual prescribed fire and (D) annual prescribed fire and grazing. Fourteen species of amphibians and six species of lizards were captured during the study period (80 days). The lowest values of amphibian richness and abundance were found in sites C and D. The amphibian species Leptodactylus ocellatus and Leptodactylus podicipinus were most abundant in the control site (A). In lizards, no significant differences were found among sites, although Kentropyx viridistriga and Teius oculatus were more abundant in annually burnt sites (C and D). Vegetation variables were correlated with amphibian and lizard species composition. The species differed in their preference for the differently managed sites. The combination of fire and grazing had a negative effect on diversity of amphibians and lizards, with a greater effect on amphibians. Also, fire favoured the presence of some lizard species.