Improved local inventory and regional contextualization for anuran (Amphibia) diversity assessment at an endangered habitat in southeastern Brazil

Abstract

Amphibians are suffering population declines around the world and the main causes are related to human activities, especially those involving direct habitat destruction. On the other hand, we are far behind in our knowledge of species distribution, natural history and even taxonomy. Some areas are under high levels of threat due to their economic relevance, as is the case for the Quadrilátero Ferrífero, a biodiverse area that is rich in iron deposits in the southernmost highlands of the Espinhaço Mountain Range, in southeastern Brazil. Using four lakes in the Quadrilátero Ferrífero as an example, we aimed to employ two approaches that we believe can improve short-term species inventories such as those needed to meet legal requirements for potentially impacting enterprises (e.g. mining). These approaches were (1) combination of tadpole and adult frog inventories and (2) regional contextualization of local species assemblages. We found adult frog and tadpole sampling to be complementary and representative of all anuran life stages. We also found the studied habitats to be considerably different from all other sampled habitats in the Quadrilátero Ferrífero (which also differed substantially among them). This high spatial heterogeneity could not be explained by geographic distance, even accounting for the effects of different types of bodies of water and sampling methods among sites. These findings have important conservation implications. Thorough inventories including both adult and tadpole stages are recommended for any new potentially destructive enterprise to be implemented in the Quadrilátero Ferrífero, because endemic species and unique anuran assemblages are likely to be lost.

Dynamic and diverse amphibian assemblages: Can we differentiate natural processes from human induced changes?

“…When we standardized sampling effort based on number of recorded individuals, species richness seemed equivalent in the two time periods. The records of tadpole and adult individuals were complementary for species inventory as also shown by [ 54 ], with the record of tadpoles aiding further to species inventory in 1998–1999. However, numbers of individuals detected in either life stage did not influence our results, considering that estimates based on both abundance and presence/absence data yielded very similar results.…”

“…Thus, in order to evaluate the effect of different sampling success (which could be due to weather conditions or chance, for instance), we also compared species richness between sampling periods based on number of individuals (adult frogs and tadpoles, both together and separately) recorded in all streams using all the available data in rarefaction curves (based on 1000 simulations) in the software EcoSim [ 53 ]. Inventories including both adult and larval stages are more efficient for anurans, especially during a short time span [ 54 ]. However, numbers of individuals can vary among life stages.…”

Ficha de Physalaemus crombiei

“…Endêmica do Brasil: Sim Physalaemus crombiei é endêmica do Brasil, tem distribuição para os estados da Bahia, Minas Gerais e Espírito Santo (Van Sluys, 1998;Tonini et al, 2010;Almeida et al, 2011;Haddad et al, 2013;Mascarenhas et al, 2015;Mageski et al, 2018), sendo amplamente distribuída neste ultimo. Sua localidadetipo é a Reserva Biológica de Nova Lombardia, no estado do Espírito Santo (Heyer & Wolf, 1989).…”

Environmental, spatial and biotic factors affect the tadpole distribution in Brazilian savannas

“…To test the effect such processes can have on determining the distribution of individuals and the composition of assemblages, we used anuran larvae as a model. Tadpoles are extremely vulnerable to desiccation, generally abundant in the bodies of water where they occur, and their distribution is spatially well delimited (Wells, 2007) which makes their capture easy (Mascarenhas et al, 2016). These larvae can occur in various types of aquatic environments from simple systems such as epiphyte tanks, tree trunk holes, or snail shells (Inger, 1985; Starrett, 1973) to more complex ones such as permanent pools.…”