Composition and ecology of a snake assemblage in an upland forest from Central Amazonia.

GABRIEL S. MASSELI,JUCIMARA G. DOS SANTOS,ALLAN D. BRUCE,IGOR L. KAEFER,TIMOTHY. VINCEN

doi:10.1590/0001-3765201920190080

Abstract

Most species of Amazonian snakes have wide geographic distributions. However, local environmental factors influence the formation of assemblages in different localities. In this study, we investigated the composition of the assemblage and the effect of environmental variables on the distribution of the species inhabiting an upland forest in the Experimental Farm area of the Federal University of Amazonas in Manaus, Brazil. Data collection was carried out in 24 standardized plots. Each plot was sampled four times between July 2015 and April 2017 by active search method. We recorded 83 individuals from 29 species belonging to six families. The richness in the study area corresponded to 78% of the snake species and 100% of the families previously recorded for Manaus. As observed in other localities, the most abundant species was the Amazonian lancehead (Bothrops atrox). Multiple linear regression models did not detect any effect of environmental variables on species richness and abundance of individuals. However, quadratic polynomial regression models revealed that intermediate canopy opening percentages positively influence the richness and abundance of snakes. It is possible that the result is related to a tradeoff between the thermoregulation behavior of these animals and to their susceptibility to predation.

Highlights

Knowledge about assemblages of Amazonian snakes is usually limited to compiling species from faunistic inventories, often supplemented by natural history observations (e.g., Guyer and Donnelly 1990, Martins and Oliveira 1998, Bernarde et al 2012, Fraga et al 2013a, Prudente et al 2018)
From these studies has emerged the idea that the fauna of Amazonian snakes is distinct from the rest of the Neotropical region (Cavalheri et al 2015) and that most Amazonian species have a wide geographic distribution, the composition of the assemblages differs between localities throughout the biome (Bernarde et al 2012)
Much of what is known about environmental effects on the composition of Amazonian snake assemblages is due to the implementation of a modular and standardized system of samplings known as RAPELD (Magnusson et al 2005, 2013)

Summary

Introduction

Knowledge about assemblages of Amazonian snakes is usually limited to compiling species from faunistic inventories, often supplemented by natural history observations (e.g., Guyer and Donnelly 1990, Martins and Oliveira 1998, Bernarde et al 2012, Fraga et al 2013a, Prudente et al 2018) From these studies has emerged the idea that the fauna of Amazonian snakes is distinct from the rest of the Neotropical region (Cavalheri et al 2015) and that most Amazonian species have a wide geographic distribution, the composition of the assemblages differs between localities throughout the biome (Bernarde et al 2012). Understanding these environmental effects continues to be a challenge because of the difficulty in detecting these cryptic species in the midst of the dense forest (Fraga et al 2014)

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Conclusion