Revista de Biología Tropical ISSN: 0034-7744 [email protected] Universidad de Costa Rica Costa Rica Neves, Frederico S.; Braga, Rodrigo F.; Araújo, Lucimar S.; Campos, Ricardo I.; Fagundes, Marcílio Differential effects of land use on ant and herbivore insect communities associated with Caryocar brasiliense (Caryocaraceae) Revista de Biología Tropical, vol. 60, núm. 3, septiembre, 2012, pp. 1065-1073 Universidad de Costa Rica San Pedro de Montes de Oca, Costa Rica Available in: http://www.redalyc.org/articulo.oa?id=44923907009 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Differential effects of land use on ant and herbivore insect communities associated with Caryocar brasiliense (Caryocaraceae) Frederico S. Neves1,2*, Rodrigo F. Braga1, Lucimar S. Araújo1, Ricardo I. Campos3 & Marcílio Fagundes1 1. Laboratório de Biologia da Conservação, Departamento de Biologia Geral, Universidade Estadual de Montes Claros, Montes claros, MG, Brasil; [email protected], [email protected], [email protected] 2. Laboratório de Ecologia de Insetos, Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil; [email protected] 3. Laboratório de Ecologia de Formigas,Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brasil; [email protected] * Corresponding author Received 03-VIII-2011. Corrected 08-II-2012. Accepted 09-III-2012. 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 mono- cultures, 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 planta- tion 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. Rev. Biol. Trop. 60 (3): 1065-1073. Epub 2012 September 01. Key words: environmental complexity, habitat management, insect diversity, pequi trees, tri-trophic interactions. Understanding natural patterns of species In fact, the cerrado represent around 1.5 to distribution and mechanisms, which determine 2.0 million km2 (approximately 20% of the these patterns, constitute the basic informa- country’s surface) and less than 50% of cer- tion for biodiversity conservation (Basset et rado’s original area remains preserved, mainly al. 2003, Samways 2007). In Brazil, studies because of agricultural expansion in central that describe the patterns of species richness Brazil (Klink & Machado 2005). and distribution have primarily focused on Caryocar brasiliense Camb. (Caryocara- the Amazon and Atlantic Forests (Myers et al. ceae) is a typical tree of the Brazilian Cerrado 2000). However, studies of this nature in the and it can be found from the Southern of Pará Brazilian cerrado (savanna) deserve special State, along the edge of the Amazon region, attention because it is considered a conserva- until the South of Paraná State and also in tion priority biome (Silva & Bates 2002). Paraguay (Gribel & Hay 1993). The extraction Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 60 (3): 1065-1073, September 2012 1065 of pequi fruits is considered an important eco- that, the aim of the present study was to test the nomic activity in different regions of Brazil, hypothesis that pequi trees located in human since these fruits are used in preparation of modified habitats, which are structurally sim- dishes, condiments, oils and sweetened bever- pler, support a lower species richness and abun- ages (Almeida & Silva 1994). During the sum- dance of ants, and a greater species richness mer, in Northern Minas Gerais State, the pequi and abundance of insect herbivores, compared fruit collection engages approximately 50% to more complex preserved cerrado habitats. of the population in rural areas, representing 54.7% of the annual income of these people MATERIALS AND METHODS (Fagundes et al. 2007). The pequi tree is legally protected in Study area: The study was conducted in Minas Gerais State (Law 10,883 of 02-20- the Cerrado biome, in Morro Alto (16°53’17” 1992), but their natural habitat has been con- S - 44°00’06’’ W), a district that belongs to stantly altered by different human land uses Montes Claros municipality, Northern of Minas such as cattle-raising pasturelands and agrofor- Gerais State (Brazil). The climate of the region estry systems. Thus these trees are commonly is considered as tropical semi-arid (Peel et found isolated in these structurally simpler al. 2007), characterized by the existence of a habitats (Fernandes et al. 2004). However, severe dry season during the winter. The aver- the pequi phenology change among different age temperature is 21°C and the annual rainfall habitats (Fagundes et al. 2007) and recently, is approximately 1 100mm, concentrated from several herbivorous insects have been observed November to January. To test the hypothesis, causing damage to the trees located in pasture three adjacent habitats (500m), with similar (M.F. personal observation). In this system, soil characteristics and density of pequi trees, ants are an important component controlling were chosen in the study area. Two habitats insect herbivores. In fact, extrafloral nectaries have been modified by human activities: cattle located on the pequi leaves serve as attractors grazing pastureland and Eucalyptus planta- to several ant species which can decrease her- tion; and one preserved area (Cerrado strictu bivore abundance (Oliveira 1997). sensu physiognomy). In each habitat 15 trees Besides the direct negative effect of ants of similar sizes (5-8m heights and diameter at on herbivores, habitat structure can modify ant breast height above 5cm) were marked in order diversity, causing an indirect effect on herbi- to characterize the herbivore insects, and ant vores (Hoffmann & Andersen 2003, Lassau & richness and abundance. Hochuli 2004, Rosumek et al. 2009). Few stud- ies have focused on insect diversity in human Sampling of ants and herbivore insects: modified habitats, including both, Eucalyptus The effects of human impact on insect fauna forests and agricultural systems (Szinicz et al. associated with pequi trees were evaluated 2005, Tylianakis et al. 2007). In studies about monthly throughout 2005. Ants and herbivore moth species from forest fragments and from insects were sampled (08:00-11:00am) using different surrounding agricultural habitats, the the beating technique (Neves et al. 2010): for species richness decreased with increasing dis- each selected plant, a branch was chosen at ran- tance to the forest fragments. It was also found dom (selected branches in small and large trees that the majority of moth species frequently had approximately the same amount of leaves), moved between forest and agricultural habitats and the branch was hit ten times with a beating (Ricketts et al. 2001). Thus, habitat simplifi- stick in order to dislodge the associated arthro- cation around the pequi trees could decrease pods on to a tray placed beneath. The insects ant diversity and, consequently, decreases the collected were taken to the laboratory and pressure of this predator on the insect herbivore sorted to the lowest taxonomic level possible, fauna associated with the same tree. Based on and deposited at the Laboratório de Biologia 1066 Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 60 (3): 1065-1073, September 2012 da Conservação, Universidade Estadual de with these trees differed significantly among Montes Claros (Unimontes). habitats (Table 2): these were lower in pequi A generalized linear model was used to trees located in the preserved area (p<0.05) verify the habitat effect on ant and insect herbi- than those from either pastureland or Eucalyp- vore richness and abundance. The mean num- tus plantation (Fig. 1C, D). ber of species or individuals per tree over the The guild of sap-sucking insects sampled 12 months of sampling was used as response was grouped into 15 Hemiptera families. Aeta- variables in order to remove the temporal pseu- lionidae (234 individuals) and Cicadellidae (21 doreplication. The habitats (preserved Cerrado, morphospecies) were the most abundant and pastureland and Eucalyptus plantation)