Mammals of medium and large size in a fragmented cerrado landscape in northeastern Minas Gerais state , Brazil

Materials and Methods Study area The study area is located at Três Rios farm (at 16°56’08.96” S, 46°16’05.83” W), approximately 36 km from Brasilândia de Minas, Minas Gerais state, Brazil (Figure 1). The region is characterized by a subtropical climate with two well-defined seasons: a dry cold season (May to September) and a rainy hot season (October to April). The mean annual temperature and precipitation are 22.5°C and 1439 mm, respectively. Três Rios is an 11,973 ha farm where much of the original vegetation has been replaced by pastures and sugar-cane plantations. Nevertheless, typical cerrado physiognomies are still found, such as: 1) savannas with scattered shrubs (‘campo sujo’); 2) open canopy woodland with a grassy savanna understory (cerrado strictu senso); 3) dense, closed, and semi-closed canopy tall woodland (‘cerradão’); and 4) riparian forests (‘mata ciliar’).


Introduction
Brazil has a high diversity of vertebrates and one of the largest Neotropical mammal fauna (over 650 species) (Reis et al. 2006;Pimm et al. 2010).Nevertheless, this exceptional diversity is still widely unknown and great part of it is seriously threatened by human activities (Drumond et al. 2005;Eduardo and Passamani 2009), especially in regions with high agricultural activity as the Brazilian cerrado (Trolle et al. 2007;Lessa et al. 2008).
The cerrado biome is a complex mosaic of plant physiognomies ranging from open grassland to closed woodlands (Ratter et al. 1997) and occupying almost 49% of the territory of the state of Minas Gerais, Brazil (Drumond et al. 2005;Bruna et al. 2010).Moreover, the cerrado holds around 13% of the Brazilian mammal diversity (approximately 194 species) (Marinho-Filho et al. 2002).Great part of this diversity is endangered since more than 40% of the biome has been converted into agriculture and the remaining is highly fragmented (Klink and Machado 2005;Drumond et al. 2005).
Most of the cerrado biome is being destroyed at high rates (Myer et al. 2000), leaving behind remnants immersed in a matrix of disturbed vegetation, pastures and crops.The matrix of altered vegetation in which the fragments are immersed can restrain the movements of the animals, change the local composition of species, and produce alterations in the community structure (Fonseca and Robinson 1990;Chiarello 2000;Lyra-Jorge et al. 2008).However, some mammal species seem to benefit from agriculture or silviculture expansion (Lyra-Jorge et al. 2008).
The study site was considered one of the priority areas for mammal conservation in Minas Gerais State (Drumond et al. 2005).However, this is the first field study aiming Abstract: The diversity of Brazilian mammals is among the highest of the world.However this exceptional diversity is still widely unknown and great part of it is seriously threatened by human activities.In the present study we estimated species richness and relative abundance of medium and large size mammals for the region of Brasilândia de Minas, a city situated in a fragmented and poorly studied cerrado area of Minas Gerais state, Brazil.We obtained 63 records of 24 species, including eight species threatened with extinction.Our results support the hypothesis that many of the cerrado mammal species may be able to persist in fragmented agricultural landscapes.This paper shows that despite the anthropogenic disturbances detected, the studied area plays an important role in the conservation of medium and large size mammals in the cerrado biome.fauna was surveyed daily for five consecutive days in four field trips, carried out in January, April and June 2010 and February 2011.We applied the following methods: (1) footprint traps (track plots) and (2) searching for mammal signs (e.g.direct observations, footprints, feces).Footprint traps were arranged along three trails created by resident farmers in different cerrado physiognomies: cerrado strictu senso, cerradão and a transitional area between a riparian forest and the sugar-cane matrix.In each of these physiognomies we set 20 footprint traps (50 X 50 cm) placed at a minimum distance of 10 meters between each other and containing food baits (banana, corn and bacon).In each month, all track plots were checked daily for five consecutive days.Searching for animal signs was conducted along trails and roads crossing the area summing 80 hours of observations in the field.Footprints were identified using field guides (Becker and Dalponte 1991;Emmons and Feer 1997;Carvalho-Junior and Luz 2008).
The relative abundance index of species (RAI) was calculated according to the model proposed by Eduardo and Passamani (2009): i/N, where i = number of records of each species; N = total number of records for all species.Only the species recorded in track plots were considered for RAI.To avoid overestimating abundance, footprints observed in the same day in each trail were treated as a single record.Representatives of the genus Mazama were not distinguished, being identified to the genus level only (Mazama spp.).The relatively completeness of the inventory was assessed through the inspection of the topology of cumulative curve (Voss et al. 2001).

Results and Discussion
We registered 23 medium to large-sized mammal species during our surveys (Table 1).The order Carnivora was the most commonly observed, with nine species of five families.In 20 days of data collection by track plots, 63 records were obtained, resulting in a sampling success of 3.1 records/day.The richness reported here for medium and large size mammals (23 species) is in accordance with other surveys carried out in cerrado areas in Brazil, which generally present between 18-29 species (Rocha and Dalponte 2006;Trolle et al. 2007;Moreira et al. 2009;Bruna et al. 2010).However, the topology of the species accumulation curve (Figure 3) does not show an asymptotic tendency, indicating that the inventory is not complete.Additional fieldwork with combination of different sampling methodologies (Moreira et al. 2008) may result in the record of more species.
Our record of species considered rare or extinct in other cerrado areas, such as P. concolor, T. terrestris and O. bezoarticus (see Trolle et al. 2007;Lyra-Jorge et al. 2008;Bruna et al. 2010), may be related to the large size of the study site (11,973 ha) which increases the probability of occurrence of suitable habitats for these species.O. bezoarticus seems to be an open habitat specialist whereas P. concolor and T. terrestris are habitat generalist species (Fonseca et. al. 1996;Reis et al. 2011).Some other generalist species with high adaptability to different kinds of habitat, such as C. thous, D. novemcinctus and Mazama sp.(Fonseca et al. 1996), were recorded with high abundance index (RAI) (Figures 4 and 5).
Other species that deserves remark is L. braccatus, which was visually identified in two occasions by the reddish fur and the characteristic dark stripes on the fore and hind limbs (Eisenberg and Redford 1999;Reis et al. 2011).The presence of the species in the Northwestern region of Minas Gerais state is somewhat unexpected, but Bagno et al. (2004) reported its presence at Grande Sertão Veredas National Park in 1998 and Cáceres et al. (2007) believe that the distribution of L. braccatus is continuous from central and Western Brazil to central Argentina, throughout the semi-open habitats of the Brazilian cerrado.Our results support the hypothesis that many of cerrado mammal species may be able to persist in fragmented landscapes (Lyra-Jorge et al. 2008;Bruna et al. 2010).Medium and large-sized mammals in fragmented agricultural landscapes may explore the region as a whole and are not constrained to the native vegetation areas (Chiarello 2000;Lyra-Jorge et al. 2008).In this study, species with large home ranges such as P. concolor, T. terrestris and P. tajacu (Emmons and Feer 1997;Chiarello 2000) confirm their ability to use landscapes that are a mosaic of natural vegetation patches and agriculture.However, the effects of fragmentation may explain why some forest species, such as Panthera onca, which are considered to be more susceptible to habitat fragmentation (Chiarello 2000;Lyra-Jorge et al. 2008), no longer occur in the study site.The fragmentation of natural vegetation is one of the main problems affecting mammal community conservation in the cerrado (Trolle et al. 2007;Lessa et al. 2008).
In this study we present the first inventory of species richness and relative abundance by medium and large size mammals in Brasilândia de Minas, a municipality inserted in a priority area for mammal conservation in Minas Gerais state, Brazil (see Drumond et al. 2005).Despite the anthropogenic influence detected, the study site plays an important regional role, promoting the persistence of threatened mammal species, consequently contributing for their conservation in the cerrado biome.

Figure 1 .
Figure 1.Map showing Brasilândia de Minas limits and study site (black dot) in Minas Gerais state, Brazil.
Four species are included in the Brazilian official list of endangered species and eight are in Minas Gerais State red list (Machado et al. 2008 -IBAMA; COPAM/MG 2010).Ozotocerus bezoarticus and Tapirus terrestris are considered Near Threatened by COPAM/MG (2010), but do not appear in the IBAMA list.Lontra longicaudis and Pecari tajacu appear as Vulnerable in Minas Gerais state red list and four carnivores (Leopardus braccatus, Leopardus pardalis, Puma concolor and Chrysocyon brachyurus) are classified as Vulnerable species in both lists (Machado et al. 2008 -IBAMA; COPAM/MG 2010) and Near Threatened by the IUCN (IUCN 2010).The endangered species recorded in this study correspond to 5.8% of the Brazilian threatened species (Machado et al. 2008 -IBAMA), and 17.8% of Minas Gerais state red list (COPAM 2010).Considering the footprints records, 3 species of the 16 species (Cerdocyon thous, Mazama sp. and Dasypus novemcinctus) presented the highest indices of relative abundance (RAI = 0.12, RAI = 0.10 and RAI = 0.09, respectively).The lowest indices (RAI = 0.01) were registered for Eira barbara, Conepatus semistriatus and O. bezoarticus (Figure2).

Figure 3 .
Figure 3. Cumulative number of species recorded per field trips during systematic survey in Brasilândia de Minas, Minas Gerais state, Brazil.

Table 1 .
Method of record and conservation status of medium and large size mammal's taxa recorded in Brasilândia de Minas, Minas Gerais state, Brazil.*Abbreviations: F = Footprints; O = Other vestiges (burrows, feces); V = Vocalization; Vi = Visualization.