The effectiveness of the larger atlantic rainforest corridor in the connectivity maintenance of large bodied mammal populations, such as the lowland tapir (Tapirus terrestris)

Abstract

This present project intends to continue a recently concluded project supported by Fapesp to researchers of the present team (2007/03392-3 - Biota-Temático for MGR and 2007/04073-1 pos-doc fellowship for AS), which had its final report well evaluated and its continuity encouraged. Mammal populations, especially the large bodied species, have suffered significant reductions as a result of hunting, habitat loss and fragmentation caused by human economic development. These environmental changes discontinue functionally habitats and consequently the gene flow of several species. The functional connectivity or the gene flow maintenance is the primary conservation strategy for the persistence of animal and vegetal species in long term. A number of studies have reported the occurrence of genetic structuring even within continuous habitats, which should function as corridors facilitating gene flow between populations. These results emphasize that other features not only the discontinuity of habitat may represent a barrier to gene flow, such as the edge effect, habitat heterogeneity along the continuum, hunting pressure, and behavioral aspects and evolutionary history of the own species. However, these studies were conducted with small bodied species. Such studies on the gene flow of larger animals in continuous areas are rare; most of them have been carried out in fragmented areas. Serra do Mar is the largest continuous of Brazilian Atlantic Rainforest representing an ideal control area for the analysis of the natural extension of the genetic structure of populations, the dispersion capacity and behavior of species, as well as effectiveness in maintaining functionally connected natural populations of different species. In a previous study, we identified a significant genetic differentiation between two populations, situated at opposite ends of this corridor, of a large bodied mammal, the lowland tapir (Tapirus terrestris). This structuring may be a result of the isolation by distance, in which the restricted dispersion and the local genetic drift create a clinal pattern with the increase of the genetic differentiation with the geographic distance. However, since this study was conducted at only two areas of the corridor, this result reveals the need to expand the sampling sites, allowing the test of the isolation by distance, and the investigation of the factors involved with the genetic pattern found, such as landscape features, behavioral of the species or historical factors of the moment colonization. Therefore, this project proposes an analysis of the genetic variability distribution in T. terrestris populations along the Serra do Mar Corridor. We will use non-invasive samples (faeces) as DNA source; microsatellite markers for the individual identification and to detect the pattern of genetic diversity contemporary distribution. New sites along the corridor are being sampled by a graduate student and a postdoctoral researcher (Bolsa PDJ CNPq 50565/2013-9). These results will be compared to mitochondrial DNA (citocromo b, citocromo c oxidase or RNA 12S) analysis in order to include a historical factor in this population study. Even the lowland tapir being present throughout the corridor, data on landscape features will be investigated, especially hunting pressure, presence of highways and proximity to urban centers, seeking to explain the genetic patterns found in this study. (AU)