Trogloregions: delimiting subterranean faunistic identities in Afrotropics and Neotropics

Abstract

Studies regarding macroecological patterns involving subterranean fauna are challenging, since the environments where such species are found generally do not have the same ecological patterns observed on the surface, due to their isolation. Therefore, using data on the occurrence of invertebrate families, we tested the influence of ecological regions already established for surface environments (biogeographic domains, biomes, and ecoregions), lithology, and drainage basins as potential drivers of the similarity on the invertebrates communities. We observed that within the surface ecoregions there might still be subdivisions due to different drainage basins, a pattern that was repeated in both aquatic and terrestrial fauna. Thus, we present different bioregions in the Afrotropics and Neotropics, in which caves have distinct faunistic identities. We discuss the biogeographic relationships between the epigean and hypogean environments that may be behind these patterns. We believe that these results can assist in conservation strategies, in which these different compositions are considered.

Collecting eco‐evolutionary data in the dark: Impediments to subterranean research and how to overcome them

“…This impediment (also known as 'Linnean shortfall'; Hortal et al, 2015) is especially problematic in studies focusing on community structure and functioning. It is particularly severe for tropical areas, whose subterranean fauna were largely unknown until very recently (e.g., Alvarenga et al, 2021;Trajano & Bichuette, 2010;Trajano et al, 2016), as well as for certain small-sized animal groups which have been traditionally neglected despite being relatively abundant in subterranean habitats, such as diplurans (Sendra, Antić, et al, 2020;Sendra, Palero, et al, 2020), proturans (Galli et al, 2021), palpigrades (Mammola et al, 2021), nematodes (Du Preez et al, 2017), gastrotrichs (Kolicka et al, 2017), and other meiofaunal lineages (Martínez et al, 2019;Sánchez & Martínez, 2019). The lack of taxonomists for many groups surely hampers the conduction of more concise studies on cave communities in many regions; a situation that is further aggravated by the existence of often high cryptic diversity within most subterranean taxa (Delić et al, 2017;Eme et al, 2018;Esposito et al, 2015;Fišer et al, 2018;Gonzalez et al, 2017;Niemiller et al, 2012).…”