Canopy and Litter Cover Do Not Alter Diaspore Removal by Ants in the Cerrado

Mariana Azevedo Rabelo,Graziele Santiago Silva,Marina Acero Angotti,Ariel Da Cruz Reis,Carla Rodrigues Ribas

doi:10.13102/sociobiology.v67i4.5658

Abstract

Diaspore removal by ants is a crucial stage for successful myrmecochory and can be directly or indirectly affected by natural or anthropic changes to environments. Among the consequences of such changes is variation in habitat attributes, such as changes in conditions and resources and, consequently, decreased diaspore removal or even the loss of this ecological function. The aim of this study was to assess whether canopy and litter cover affect diaspore removal by ants in the Cerrado. We considered canopy and litter cover as proxies of humidity and temperature and evaluated whether changes in these environmental conditions could affect diaspore removal by ants. We hypothesized that the greater the canopy and litter cover (higher humidity and lower temperature), the greater the number of diaspores removed by ants. We tested this hypothesis by establishing three classes of cover for each proxy: low, intermediate, and high. We placed artificial diaspores under each cover class and quantified the number of diaspores removed. We found that variation in canopy and litter cover did not affect the number of diaspores removed by ants in areas of cerrado sensu stricto. Variation in habitat attributes in natural environments were less important for diaspore removal than in modified areas. Our results indicate that understanding the processes and habitat atributes involved in diaspore removal by ants is important for conserving the Cerrado.

Highlights

Increased habitat fragmentation and habitat loss, and the consequent decline in species richness, due to anthropogenic activities can have direct and indirect effects on ecological processes, such as diaspore removal by ants (Christianini et al, 2007; Bieber et al, 2014)
To determine whether the number of diaspores removed by ants is influenced by environmental conditions and resources, we considered canopy and litter cover as proxies for such environmental characteristics, temperature and humidity
Of the 300 artificial diaspores provided for each canopy cover class, 253 diaspores were removed for Low cover (LC), 278 for intermediate cover (IC), and 231 for high cover (HC)

Summary

Introduction

Increased habitat fragmentation and habitat loss, and the consequent decline in species richness, due to anthropogenic activities can have direct and indirect effects on ecological processes, such as diaspore removal by ants (myrmecochory) (Christianini et al, 2007; Bieber et al, 2014). Highlighted among the direct effects are changes in the composition of ant assemblages, which could involve a decrease or loss of highquality diaspore removing species and increased removal by generalist species, with a negative effect on removal success (Zelikova & Breed, 2008; Leal et al, 2014). The main indirect effects of habitat disturbance are associated with effects on habitat structure, microclimate, resource availability and competitive interactions (Andersen, 2018).

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