Diversity and composition of the spider fauna in a semideciduous Atlantic forest area in Rio de Janeiro state, Brazil

Abstract

ABSTRACT This spider survey of a semidecidual forest area in the city of Mendes, in Rio de Janeiro state, Brazil, aims to increase the scant knowledge about spider communities in this Brazilian ecosystem. Samples were taken over a year, once every three months, in four different sites with seven sampling methods. An overall of 457 species/morphoespecies were recorded in 47 families, corresponding to 10,541 individuals sampled. Families with highest number of species were Theridiidae (91), Araneidae (72), and Salticidae (55). Families with highest abundance were Theridiidae (2,829 specimens), Pholcidae (2,328), and Araneidae (1,263). Most abundant species were Mesabolivar togatus(534), Carapoia lutea(499 individuals), and Cryptachaea digitus (387). Species accumulation curves indicate a minimum of 513 (Bootstrap) and a maximum of 653 species (Jackknife2) for sampled areas. Total Berger-Parker dominance index was low, 0.051, varying from 0.042 to 0.076, while total Pielou equitability Index was high, 0.805, ranging from 0.744 to 0.800. Total Shannon-Wiener diversity index was relatively high, 4.931, ranging from 4.559 to 4.899. The complex, very diverse and relatively well-structured spider community found in Mendes is remarkable, especially in an area with predominantly secondary forests and high anthropic influence.