Diversidade da herpetofauna em uma área com diferentes estágios de sucessão natural de Caatinga, no semiárido paraibano.

Abstract

Caatinga is a biome located in the semi-arid region, which receives little attention for studies on fauna composition, especially in regions with high levels of degradation. Therefore, this study aimed to understand the relationship between herpetofauna, abiotic factors and environmental variables in an area undergoing natural succession located between the cities of Santa Luzia-PB and Várzea-PB. The site is classified as an area of arboreal shrub caatinga in process of succession and is divided into: 1-advanced stage; 2-medium stage; 3-initial stage; 4- native pasture. The survey occurred through active search, pitfall traps, occasional encounters coupled with the collection of abiotic and vegetational data (4x4m plots) along the pitfalls sets (n=96 plots). We recorded 484 sightings of amphibians, 1,004 of lizards and 32 of snakes, totaling 35 species: 17 amphibians, 12 lizards and 6 snakes. The anurans consisted of 6 families, with Leptodactylidae and Hylidae having the highest richness. The lizards showed 7 families, with Gekkonidae having the highest richness (n=3) and for the snakes, 3 families, with Dipsadidae being the richest. Kruskal-Wallis found no differences among the four areas (H=1.301; p=0.605). Principal Component Analysis (PCA) showed correlation between richness and sightings with the number of rocks, degree of canopy cover, height of burlap, approximate height of vegetation, height and density of understory, number of trees, PAC, number of fallen branches, air humidity, soil moisture, and percentage of herbaceous plants. The Kruskal-Wallis test also showed that 9 of the 22 variables were correlated with species occurrence. From these results, it is possible to infer that the dry season is a restrictive factor, occurring the predominance of generalist species such as A. ocellifera, T. hispidus, T. semitaeniatus and also species that are only sighted after the first rains such as C. greeningi and D. muelleri. Environmental heterogeneity acts as one of the main factors explaining local diversity, since the richness for each study area was directly correlated to environmental variables.