Comunidades de lagartos dos remanescentes de restinga do Estado do Rio de Janeiro: Riqueza, diversidade e onde estão as espécies endêmicas e ameaçadas de extinção

Abstract

Currently there is a continuing loss of biodiversity, which occurs primarily due to intense modification of landscapes by human activities. The coast of the state of Rio de Janeiro is occupied for hundreds of years, and one of the main threats is the increasing demography rate. In general, the knowledge of different groups of terrestrial vertebrates and its relation to the restinga environment is still incipient. We conducted this study in ten different areas of restinga remnants in the state of Rio de Janeiro, to understand how the communities of lizards vary between different environments and how they structure locally, as well as the main factors that affect them negatively. We performed a set of linear transects limited by time, over three years. The lizard species were identified and quantified, and the structure and anthropogenic factors threatening environments were measured. We recorded a total of nine species of lizards comnposing the communities of the restinga areas sampled in the state of Rio de Janeiro, including an exotic and invasive species (Hemidactylus mabouia), and two endemic and threatened with extinction (Cnemidophorus littoralis and Liolaemus lutzae). Most species were recorded in different meso-habitats, and in general can be considered opportunistic and generalist. The restinga remnants differed mainly in terms of abundance and density of species of lizards, while the richness was comparatively lower in island environments. Probably these differences are the result of the interaction between historical and ecological processes acting in synergy. For the restinga of Grussaí, the data show that the community is structured in the time axis, considering the three niche dimensions evaluated (time, space and diet). The analysis of the anthropogenic factors threatening the restingas shows that thefragments remained the mostly the same in recent years. Probably, the current public policies are not enough to increase the degree of preservation and conservation of the restinga areas of the state of Rio de Janeiro due to continued real estate speculation. It is necessary to employ periodic monitoring to supervise the situation of the populations of endemic and endangered species, and promote physical changes (e.g. removal of waste and exotic species), socio-educational (e.g. reduced access of domestic animals, disposal of material ) and government (e.g. increase in protected areas). In relation to the endemic species L. lutzae threatened with extinction, we identified a niche overlap in relation to space use of Tropidurus torquatus, which variated between the sampled locations. Probably this variation results from the environmental structure that differs between the areas and consequently causes different responses in terms of interaction between species that compose the lizard communities. The new records of H. mabouia in natural restinga habitat were inserted to the literature records of the species occurring in natural environments in Brazil, in order to identify potential areas of invasion of the species. The results show a high probability mainly in the coastal region. This study provides a better understanding of the community ecology of lizards in the state of Rio de Janeiro.