Soil and forest structure predicts large-scale patterns of occurrence and local abundance of a widespread Amazonian frog

Abstract

The distribution of biodiversity within the Amazon basin is often structured by sharp environmental boundaries, such as large rivers. The Amazon region is also characterized by subtle environmental clines, but how they might affect the distributions and abundance of organisms has so far received less attention. Here, we test whether soil and forest characteristics are associated with the occurrence and relative abundance of the forest-floor dwelling Aromobatid frog, Allobates femoralis. We applied a structured sampling regime along an 880 km long transect through forest of different density. High detection probabilities were estimated for A. femoralis in each of the sampling modules. Using generalized linear mixed-effects models and simple linear regressions that take detectability into account, we show that A. femoralis is more abundant in open forests than in dense forests. The presence and relative abundance of A. femoralis is also positively associated with clay-rich soils, which are poorly drained and therefore likely support the standing water bodies required for reproduction. Taken together, we demonstrate that relatively easy-to-measure environmental features can explain the distribution and abundance of a widespread species at different spatial scales. Such proxies are of clear value to ecologists and conservation managers working in large inaccessible areas such as the Amazon basin.

Spatio-Temporal Characteristics of the Prolonged Courtship in Brilliant-Thighed Poison Frogs, Allobates femoralis

“…Allobates femoralis (Dendrobatidae: Aromobatinae; Pyron and Wiens 2011; AmphibiaWeb 2019; but see Grant et al 2017 andGuillory et al 2019) is a small, diurnal, leaf litter frog distributed in the Amazon basin and the Guiana shield (Amézquita et al 2009(Amézquita et al , 2017Ferreira et al 2018). During the prolonged reproductive season, which coincides with the local rainy season (Gottsberger and Gruber 2004;Montanarin et al 2011), male Al.…”

Environmental filtering and deforestation shape frog assemblages in Amazonia: An empirical approach assessing species abundances and functional traits

“…The species most common to these areas were terrestrial species known to be associated with deforestation in other areas in the Amazon (Menin et al, 2019;Tsuji-Nishikido & Menin, 2011), so it is unlikely that they were more common there only because of the greater silt availability. Additionally, some species that did not occur in these areas are found in areas with high silt content (e.g., Allobates femoralis, Ferreira et al, 2018), so it is unlikely that their absence from the most disturbed areas was because of excess silt. Future studies should focus For species and trait abbreviations, see Tables 1 and 2, respectively on investigating the effects of deforestation on soil structure, especially in regard to silt content, which has been little discussed in studies of Amazonian frogs.…”

Not as widespread as thought: Integrative taxonomy reveals cryptic diversity in the Amazonian nurse frog Allobates tinae Melo‐Sampaio, Oliveira and Prates, 2018 and description of a new species

“…The northern portion of the IPM is characterized by high silt and shallow groundwater soils, and it is covered by dense lowland forest predominantly formed by trees and shrubs of small basal area (Cintra et al., 2013; Ferreira et al., 2018; IBGE, 2012; Schietti et al., 2016). On the other hand, the southern portion of the IPM has predominantly clayish soils, being mainly covered by open lowland forest constituted by trees of larger basal area when compared to the northern portion (Cintra et al., 2013; Ferreira et al., 2018; IBGE, 2012; Schietti et al., 2016). Besides that, the average annual rainfall in the IPM ranges from ~2,100 mm in the southern portion to ~2,800 mm in the northern portion of the interfluve (Alvares, Stape, Sentelhas, Gonçalves, & Sparovek, 2014).…”

“…Recent taxonomic (e.g., Simões, Rojas, & Lima, 2019), systematic (e.g., Grant et al., 2017), phylogeographic (e.g., Maia, Lima, & Kaefer, 2017), and ecological (e.g., Ferreira, Jehle, Stow, & Lima, 2018) studies have improved our understanding of the diversity and geographic distribution of Allobates . It is currently known that most Amazonian Allobates species are not widely distributed.…”