PARENT SESSION
Poster Session 30: Invertebrate Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Habitat structure and spatial distribution of a para-epigean cave community, Brazil.

Prous, Xavier¹, Ferreira, Rodrigo¹, Jacobi, Claudia^*,1, ¹ Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil

ABSTRACT- Caves are ecosystems characterized by a permanent absence of light, constant temperature, moisture approaching saturation and low food availability. The distribution of cave organisms is influenced by several factors, such as potential food resources and habitat structure, and diversity is comparatively low. These conditions make caves a good model system for ecological studies. Para-epigean communities are those occurring near the cave entrance, the part of the cave more subjected to environmental changes. They are composed of epigean (aboveground) and hypogean (underground) organisms. The aim of this research was to detect possible overlaps among habitat, trophic structure, and the spatial distribution of arthropod species in a limestone cave. The study was carried out in Lapa do Mosquito cave, southeastern Brazil. Spatially constrained clustering and the lattice wombling algorithm were used to map the distribution of the species and habitat features, and to detect zones of rapid changes (boundaries) on species richness and total arthropod abundance. The first 80 m of the main conduct of the cave was divided into 278 square sections (4 m²). In each one, ground arthropods were collected, and temperature, moisture, light, organic matter and structural habitat complexity were measured. Organic mater, light, moisture, and temperature did not show significant correlation with either species richness or arthropod density. However, some trophic categories were spatially structured. Three generalist predators, two spiders (Loxosceles similis and Oecobius navus), and one true bug (Zelurus sp.) showed significant boundary avoidance in their distribution, suggesting interspecific competition or different strategies of habitat exploitation on account of their size and mobility.

Key words: cave arthropod community, spatial structure, spatial analysis