Differential effects of land use on ant and herbivore insect communities associated with Caryocar brasiliense (Caryocaraceae)

Frederico S Neves,Ricardo I Campos,Marcílio Fagundes,Rodrigo F Braga,Lucimar S Araújo

doi:10.15517/rbt.v60i3.1758

Abstract

Simplification of natural habitats leads to a modification of the community associated with a host plant. Pequi trees (Caryocar brasiliense) are common to find in central Brazil, especially in the middle of monocultures, such as soy, corn, pasturelands or Eucalyptus plantations. On this scenario we hypothesized that habitat modification differentially affects the diversity of ants and herbivore insects associated with this species. The aim of the work was to test if C. brasiliense trees located in human modified habitats, support a lower species richness and abundance of ants, and a greater species richness and abundance of insect herbivores, compared to preserved cerrado habitats. The study was conducted in a Cerrado area located in Northern Minas Gerais State, Brazil. Ants and herbivore insects were collected monthly during 2005 using beating technique. The results showed that ant species richness was higher in pequi trees located in preserved Cerrado, followed by trees in pastureland and Eucalyptus plantation, respectively. The ant abundance was lower in the Eucalyptus plantation but no difference in ant abundance was observed between trees in pastureland and the preserved Cerrado. Moreover, herbivore insects exhibited lower number of species and individuals in trees located in the preserved Cerrado than in the pastureland and Eucalyptus plantation. We concluded that habitats simplified by human activities may result in diversity loss and may change species interactions.

Highlights

The cerrado represent around 1.5 to 2.0 million km2 and less than 50% of cerrado’s original area remains preserved, mainly because of agricultural expansion in central Brazil (Klink & Machado 2005)
The pequi tree is legally protected in Minas Gerais State (Law 10,883 of 02-201992), but their natural habitat has been constantly altered by different human land uses such as cattle-raising pasturelands and agroforestry systems
The ant species richness associated with pequi trees varied among habitats (Table 2)

Summary

Introduction

The cerrado represent around 1.5 to 2.0 million km (approximately 20% of the country’s surface) and less than 50% of cerrado’s original area remains preserved, mainly because of agricultural expansion in central Brazil (Klink & Machado 2005). The pequi tree is legally protected in Minas Gerais State (Law 10,883 of 02-201992), but their natural habitat has been constantly altered by different human land uses such as cattle-raising pasturelands and agroforestry systems. The pequi phenology change among different habitats (Fagundes et al 2007) and recently, several herbivorous insects have been observed causing damage to the trees located in pasture (M.F. personal observation). The aim of the present study was to test the hypothesis that pequi trees located in human modified habitats, which are structurally simpler, support a lower species richness and abundance of ants, and a greater species richness and abundance of insect herbivores, compared to more complex preserved cerrado habitats

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Conclusion