Population density and conservation status of the teiid lizard Cnemidophorus littoralis, an endangered species endemic to the sandy coastal plains (restinga habitats) of Rio de Janeiro state, Brazil

Abstract

The threatened lizard Cnemidophorus littoralis occurs in only four restinga habitats of Brazilian coast and its current conservation status is “endangered”. Due to its restricted distribution, the effects of habitat degradation are especially harmful to them. To prevent a local or even total extinction, we analyzed changes in population density and in amount of disturbances of three restinga areas during a seven-year gap. This study took place in three restingas of Rio de Janeiro State, Brazil: Marica, Jurubatiba and Grussai. We compared C. littoralis current density with the one registered in 2005 by Menezes and Rocha (2013) with 2 ha transections in each restinga. We also made another group of transects to estimate population density along the entire extension of the restingas. Conservation index of each site was based on satellite images and field samplings. Data showed a decreasing trend of Cnemidophorus littoralis population density over the years. Grussai had the lowest population density and the highest degradation index among the three sites, whereas Jurubatiba had the lowest degree of disturbance, the largest area and the highest lizard population density. Data showed an increase in the amount of disturbance in restingas over the years, which seemed to have a negative effect in C. littoralis population density. Improvement of surveillance and implementation of education programs in the protected areas and its surroundings, and periodic monitoring of C. littoralis populations to follow their density changes, are essential for the maintenance of the species.