Diversity of spiders (Arachnida: Araneae) of an urban forest fragment in the Atlantic rainforest (São Paulo, Brazil)

Abstract

The abundance of spiders in most terrestrial ecosystems makes them good indicators of habitat changes because they are common animals in most terrestrial ecosystems. Due to the importance of knowing the diversity of spiders for conservation efforts and the lack of studies on the spider fauna in urban parks, this work aimed to collect and identify the diversity of spiders present in an isolated fragment of native Atlantic Rainforest vegetation, in an urban area on Diadema, São Paulo. We used pitfall traps over 28 days and active nocturnal search for two hours per night over 6 nights as collection methods. We found a total of 328 individuals, of which 118 adult spiders were assigned to 13 families and 37 morphospecies. Species of families Nemesiidae, Theraphosidae and Deinopidae were found, which are not expected in urban areas. The highest values of abundance were found for the Theridiidae family, with 59 individuals and Araneidae with 28, totaling 73.7% of the total sampled, with Nephilingis cruentata and Parasteatoda tepidariorum being the most abundant morphospecies, with 15 and 11 adult individuals collected, respectively. The richness found in this work was 37 morphospecies and according to the diversity estimators Chao 1 and 2 and Jacknife 1 and 2, it was estimated that the richness of the Diadema Botanical Garden is between 44 and 54 species, a result close to the number of species collected, which indicates that the sampling effort of this work was satisfactory. This work is one of the few inventories of spider fauna in urban fragments of the Atlantic Rainforest and the first study in the Diadema city, one of the cities with the highest population density in the country. It is important to empathize that the results showed a rich and diverse araneofauna when compared with other similar studies, even in an extremely isolated fragment in one of the cities with the highest population density in the state. Public policies specifically aimed at the conservation of these areas should be encouraged so that their preservation is secured.