Invertebrates diversity in mountain Neotropical quartzite caves: which factors can influence the composition, richness, and distribution of the cave communities?

Marconi Souza Silva,Luiz Felipe Moretti Iniesta,Rodrigo Lopes Ferreira

doi:10.3897/subtbiol.33.46444

Abstract

Twenty caves located in a high altitudinal quartzite area in Brazil were examined for invertebrate richness and composition and in terms of environmental factors that determine community structure. We evaluate how distance, altitude, cave extension, environmental stability, number and size of cave entrances and stream presence can act on species composition and richness. The caves presented a high richness of troglophilic (463 spp.) and troglobitic species (6 spp.) in relation to other siliciclastic caves around the world. The average richness was 39.55 species per cave (sd = 21.87), the quantitative similarity among caves was 41% and turnover was βrepl. = 0.769. Araneae (20% of the sampled species), Diptera (18%) and Coleoptera (14%) were the dominant orders regarding species richness. Only twenty percent of the caves were placed out of the confidence interval of the average taxonomic distinctness (∆+); however, the ∆+ decreased with the increase of environmental stability. Cave extension and stream presence were the main factors determining the variation of species composition among caves. Cave extension also influenced species richness variations. Furthermore, the total richness and richness of troglobitic species increased with cave extension. The threats to these habitats further revealed that the fauna is at risk due to tourism, trampling and natural soil erosion that can promote microhabitat alterations. Therefore, quartzite caves also require special attention regarding conservation actions in order to keep their natural biological dynamics.

Highlights

Studies related to ecology and conservation of subterranean fauna have been receiving increasing attention in recent years (Mammola 2018, Mammola and Isaia 2018, Pellegrini et al 2018, Moldovan et al 2018)
Despite quartzite caves being less frequent than caves in other lithologies, studies with fauna from these habitats have been conducted in some regions of the world, as in Cape Peninsula in South Africa (Sharratt et al 2000), in the Northwestern United States (Peck and Peck 1982), in the Amazon Tepuis in South America (Galán and Herrera 2006, Aubrecht et al 2012), in the Brazilian Atlantic Rain Forest (Zeppelini et al 2003, Gallão and Bichuette 2015) and in Brazilian Savannah (Guadanucci et al 2015)
Besides the influence of potential epigean colonizers, the higher average richness found in the present work (39.55 spp., SD = 21.87 spp.) may have been influenced by the size of the studied caves, which can promote a greater heterogeneity of habitats and support richer fauna

Summary

Introduction

Studies related to ecology and conservation of subterranean fauna have been receiving increasing attention in recent years (Mammola 2018, Mammola and Isaia 2018, Pellegrini et al 2018, Moldovan et al 2018). Despite quartzite caves being less frequent than caves in other lithologies, studies with fauna from these habitats have been conducted in some regions of the world, as in Cape Peninsula in South Africa (Sharratt et al 2000), in the Northwestern United States (Peck and Peck 1982), in the Amazon Tepuis in South America (Galán and Herrera 2006, Aubrecht et al 2012), in the Brazilian Atlantic Rain Forest (Zeppelini et al 2003, Gallão and Bichuette 2015) and in Brazilian Savannah (Guadanucci et al 2015). Most of the knowledge on cave ecology in Brazil comes from works conducted in limestone caves (Bento et al 2016, Pellegrini et al 2016, Simões et al 2015, Rabelo et al 2018)

Objectives

Methods

Results

Conclusion