Estrutura das comunidades de répteis e anfibios terrestres em ambientes nativos e antrópicos na floresta nacional de Nisia Floresta, Rio Grande do Norte, Brasil

Abstract

One of the objectives in community ecology is to understand which factors are responsible for biological diversity. Landscape parameters provide fundamental answers about the patterns of distribution, species richness, and abundance. Amphibians and reptiles are model groups in studies that relate communities to landscape alterations and habitat structure. The Atlantic Forest is a global biodiversity hotspot and has been subjected to high anthropogenic pressure for years. The Nísia Floresta National Forest is a protected area that protects a remnant of the Atlantic Forest in the state of Rio Grande do Norte. The area is characterized by native vegetation (Atlantic Forest, "Restinga or Tabuleiros") as well as abandoned exotic plantation areas. This study is divided into two chapters. The first chapter had the following objectives: 1- Conduct a survey of the herpetofauna of the Nísia Floresta National Forest and create an official list for the unit. 2- Compare the diversity of reptiles and amphibians in different areas considering variations in vegetation types. The second chapter aimed to: 3- Investigate the relationship between the diversity of reptiles and amphibians with landscape and microhabitat variables, identifying which factors best explain diversity. To achieve the objectives of the first chapter, we used standardized and long-term sampling, along with visual and occasional encounters. We conducted monthly surveys throughout the area using 84 pitfall traps randomly distributed in 21 arrays across the three phytogeographic zones (restinga, forest, and regeneration). We collected a total of 39 species of reptiles (including lizards, snakes, turtles, crocodilians, and amphisbaenians) and 24 species of amphibians. The most numerous reptile family was Dipsadidae, followed by Colubridae. For amphibians, the most numerous was Leptodactylidae, followed by Hylidae. The diversity of herpetofauna in regeneration areas is lower than in forests, which in turn are marginally less diverse than Restinga. Although diversity in regeneration areas is lower, it is similar to natural areas. For the second chapter, we used richness and abundance data obtained only from the traps. We measured 10 microhabitat parameters at each pitfall trap array, and we used two landscape metrics to test the effect on communities, using QGIS. To identify which variables best explained the richness and diversity of the herpetofauna, we employed a GLM with the minimal adequate model approach. Distance to the pond explained total richness. Distance to the pond and vegetation density explained total diversity. Also, distance to the pond and vegetation density explained amphibian richness and diversity, while canopy cover explained reptile richness.