Species composition and reproductive modes of anurans from a transitional Amazonian forest, Brazil

Abstract

ABSTRACT. The aim of the present study was to describe the species composition and reproductive modes of an anuran community from a transition area between the Amazonia and Cerrado biomes. Data were collected in habitats exhibiting different degrees of anthropogenic degradation. The community (35 species) identified during the present study presented a larger number of reproductive modes when compared with those from Cerrado communities, but smaller than those of other sites in the Amazon. While all nine modes were recorded in the gallery forests of local rivers and streams, anthropogenic habitats (rubber tree orchards and soybean fields) were occupied only by species adapted to environments where humidity is low, typical of the Cerrado. Overall, the anuran fauna of the study area was characterized by species that depend on access to water bodies for their reproduction, with only a few specialized species able to reproduce in dry environments.

Composition and ecological patterns of snake assemblages in an Amazon-Cerrado Transition Zone in Brazil

“…Thus, the disturbances have not turned the study site (when we analyzed the total area) into a homogeneous area, which is associated to an overt loss of species (Olden et al, 2004). However, we can observe losses when analyzing the sites separately, as observed for amphibians (Bitar et al, 2012).…”

Ponds, puddles, floodplains and dams in the Upper Xingu Basin: could we be witnessing the ‘lentification’ of deforested Amazonia?

“…Because calling involves not only benefits (mate attraction and selection) but also costs (energetic costs, increased risk of predation and parasitism), males usually call in, at or close to their breeding sites [30]. Therefore, the lack of water bodies is a sufficient explanation for the absence of calling amphibians in forested plateaus, as 35 of 38 amphibian species in the region depend on water for egg laying and/or premetamorphic development [31]. We suspect the lack of a statistical effect of density of ponds and puddles on amphibian richness and abundance results primarily from the need to exclude forested plateaus from the analysis, and secondarily from a mismatch in the scale of habitat assessment (ponds that could be seen from transect, i.e., tens of meters) and that of faunal assessment (frogs that could be heard from transect, i.e., hundreds of meters).…”

“…The increase in species richness is, by contrast, unexpected. Differences in observed gamma diversity are likely artifacts of abundance; Chao estimators predict 29 species in forests, less than the 38 recorded [31] but more than the 22 predicted in converted land. Differences in alpha diversity, in turn, do not appear to be artifacts and could be due to the particular biogeographical scenario of our study site and/or the spread of generalistic open area species with deforestation (see also 34).…”

Anuran Beta Diversity in a Mosaic Anthropogenic Landscape in Transitional Amazon

“…In the gallery forests, these environments are perennial and are naturally impounded in many locations, providing breeding sites for species that reproduce in both lotic and lentic environments (Bitar et al, 2012). Also, forest habitats are much less susceptible to sudden changes in temperature and humidity, which makes these habitats more stable and, thus, more favorable to a larger number of species than areas of secondary habitat, which may be more variable to temperature and humidity fluctuations and also be at a successional stage characterized by the recolonization of native species and the colonization of invasive species (Scott, 1982;Heinen, 1992).…”

“…Study Area.-The study area is located on the Fazenda Tanguro, a ranch in the municipality of Querˆencia, in the Brazilian state of Mato Grosso (datum SAD 69, 13804 0 35.39 00 S, 52823 0 08.85 00 W), within a transition zone between the Amazonian forest and Cerrado savanna biomes, which is vulnerable to the ongoing expansion of agricultural frontiers in the region known as the ''Arc of deforestation'' (Balch et al, 2008;Hayhoe et al, 2011;Bitar et al, 2012). This property encompasses an area of 82,000 ha, of which 38,000 ha are agricultural land (soybean and rubber plantations) and 44,000 ha are forest, natural gallery forest, or regenerating habitat.…”