Quantifying Responses of Dung Beetles to Fire Disturbance in Tropical Forests: The Importance of Trapping Method and Seasonality

Rafael Barreto De Andrade,Fernando Zagury Vaz-De-Mello,Juliana M Silveira,Jos Barlow,Julio Louzada,Mark A Cochrane,Mateus Souza,Nicolas Chaline

doi:10.1371/journal.pone.0026208

Rafael Barreto De Andrade, Fernando Zagury Vaz-De-Mello + Show 6 more

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https://doi.org/10.1371/journal.pone.0026208

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Abstract

Understanding how biodiversity responds to environmental changes is essential to provide the evidence-base that underpins conservation initiatives. The present study provides a standardized comparison between unbaited flight intercept traps (FIT) and baited pitfall traps (BPT) for sampling dung beetles. We examine the effectiveness of the two to assess fire disturbance effects and how trap performance is affected by seasonality. The study was carried out in a transitional forest between Cerrado (Brazilian Savanna) and Amazon Forest. Dung beetles were collected during one wet and one dry sampling season. The two methods sampled different portions of the local beetle assemblage. Both FIT and BPT were sensitive to fire disturbance during the wet season, but only BPT detected community differences during the dry season. Both traps showed similar correlation with environmental factors. Our results indicate that seasonality had a stronger effect than trap type, with BPT more effective and robust under low population numbers, and FIT more sensitive to fine scale heterogeneity patterns. This study shows the strengths and weaknesses of two commonly used methodologies for sampling dung beetles in tropical forests, as well as highlighting the importance of seasonality in shaping the results obtained by both sampling strategies.

Highlights

Understanding how biodiversity responds to environmental changes is essential to provide the evidence-base that underpins conservation initiatives [1]
Our results indicate that seasonality had a stronger effect than trap type, with baited pitfall traps (BPT) more effective and robust under low population numbers, and flight intercept traps (FIT) more sensitive to fine scale heterogeneity patterns
We address the following specific hypotheses: 1. The two methodologies (FITs and BPTs) sample complimentary parts of the dung beetle assemblage, and there would be a significant difference in the biodiversity metrics recorded by each method

Summary

Introduction

Understanding how biodiversity responds to environmental changes is essential to provide the evidence-base that underpins conservation initiatives [1]. Forest fires are considered a major threat to tropical natural environments [8,9,10], affecting vegetation structure, local biodiversity and forest dynamics [11,12,13,14,15]. Studies on tree mortality and forest structure (see [11] for review), understory avian communities [12], fruit production and large vertebrates [13] and invertebrates [17] show the multiple consequences of fires in the humid Neotropics. Seasonality can play a significant role in biodiversity parameters when assessing disturbance impacts on invertebrates [21,22]

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