Juxtaposition and Disturbance: Disentangling the Determinants of Lizard Community Structure

Abstract

Disturbance alters the structure and dynamics of communities. Here, we examined the effects of seasonal flooding on the lizard community structure by comparing two adjacent habitats, a seasonally flooded and a non-flooded forest, in a Cerrado-Amazon ecotone area, the Cantão State Park, Tocantins state, Brazil. Despite the strong potential impact of seasonal flooding, the only significant environmental difference detected was more termite mounds in non-flooded forests. Species richness was significantly higher in the non-flooded forest. Colobosaura modesta, followed by Mabuya frenata and Anolis brasiliensis, were the only species that differed in number of captures between sites. Colobosaura modesta was exclusively found in the non-flooded forest, while Anolis brasiliensis was the most captured in the flooded forest. Mabuya frenata is indicated as an indicator species in the flooded forest, and Colobosaura modesta in the non-flooded forest. We found a significant association between lizard abundances and habitat characteristics, with flooding, canopy cover, and logs being the best predictors. A phylogenetic community structure analysis indicated a lack of structure in both lizard assemblages. Overall, we show that seasonal flooding can strongly impact species richness and species occurrence patterns, but not phylogenetic community structure. The Amazon-Cerrado transition is undergoing pronounced transformations due to deforestation and climate change. Despite being species-poor compared with central areas in Amazon or Cerrado, this ecotone harbors species with important adaptations that could hold the key to persistence in human-disturbed landscapes or during periods of climate change.Abstract in Portuguese is available with online material.

The role of environmental gradients and microclimates in structuring communities and functional groups of lizards in a rainforest-savanna transition area

“…Spatial heterogeneity of vegetation and vegetation cover are known to affect the occurrence and abundance of squamates in the tropics, as they are related to the availability of resources and sites for nesting, foraging, thermoregulation ( Vitt & Zani, 1998 ; Vitt et al, 2007 ; Pringle, Webb & Shine, 2003 ; Masseli et al, 2019 ; Mesquita et al, 2015 ) and variation of light incidence, humidity and temperature ( Pringle, Webb & Shine, 2003 ; Peixoto et al, 2020 ). The communities sampled herein are also affected by these factors since they are structured along a gradient of plant structure, which is represented by canopy reflectance, varying in the availability of open environments with a high incidence of light, temperature, and humidity, as well as forest environments with a lower incidence of direct light and milder temperatures.…”

Deforestation limits evolutionary rescue under climate change in Amazonian lizards

“…In Amazonia, a west‐to‐east climate gradient is marked by an increase in climate seasonality eastwards and in the direction of the Cerrado (Cheng et al., 2013). These gradients influence biodiversity patterns of multiple taxonomic groups at various levels, with biodiversity generally decreasing towards the east (Mesquita et al., 2015; Ter Steege et al., 2015). The distribution of K. calcarata mostly in eastern Amazonia may explain the dominance of the dry/seasonal genotype relative to the wet/non‐seasonal one.…”

Taxonomic, functional, and phylogenetic diversity of lizard assemblages across habitats and seasons in a Brazilian Cerrado area

“…The species Cercosaura parkeri, Stenocercus sinesaccus and Tropidurus lagunablanca were not included in that phylogeny, so we substituted them by C. schreibersii, Stenocercus caducus and Tropidurus spinulosus respectively. We assumed that these substitutions would not affect the results, because evolutionary changes generally occur in deep nodes (Mesquita et al 2015). We then calculated two indices: phylogenetic species variability (PSV)which quantifies the variance in phylogenetic relationships between species in a community and phylogenetic species richness (PSR), a measure of local species richness multiplied by PSV, to penalize strongly related species within the community (Helmus et al 2007).…”

“…We assumed that these substitutions would not affect the results, because evolutionary changes generally occur in deep nodes (Mesquita et al . 2015). We then calculated two indices: phylogenetic species variability (PSV) – which quantifies the variance in phylogenetic relationships between species in a community – and phylogenetic species richness (PSR), a measure of local species richness multiplied by PSV, to penalize strongly related species within the community (Helmus et al .…”