Occupancy and detectability of a critically threatened lizard endemic from sandy coastal plains areas of Rio de Janeiro State, Brazil

Abstract

AbstractLiolaemus lutzae is a small liolaemid lizard critically endangered and restricted to coastal restinga (salty sand dune habitats covered by herbaceous and shrubby vegetation by seaside) habitats of the state of Rio de Janeiro in Brazil. This lizard has been predicted to be extinct by 2080. We studied some of the environmental factors that influence occupancy by the species and detectability by the observer, in addition to investigating which populations remain occupying the areas along its original geographical distribution. We sampled 25 different beach habitats of restinga areas in the state, by 100‐meter replicates of linear transects. The estimated probability of occupancy was 69% (0.69 ± 0.05), and the estimated detectability was 50% (0.50 ± 0.03). The detection model with the best fit contained only the air temperature variable. Occupancy was best described by four variables: number of disturbance sources on the transect, vegetation cover in a 50‐meter buffer, exposed sand cover substrate in a 20‐meter buffer, and built‐up area cover in a 50‐meter buffer. No observations of L. lutzae were made in eight of the 25 restinga areas sampled along the original distribution of the lizard. In seven of these areas, the species had its populations extirpated many years ago, based on the 2007/2008 monitoring data. Conversely, in one area where the species was frequently observed during field surveys and different ecological studies on the species made in last decade, it was not recorded in the present study, indicating a possible recent population extirpation. We recommend that conservation measures be urgently implemented to mitigate anthropogenic impacts on the areas of the remaining populations of this lizard throughout its range, especially preserving the structure and functions of the remaining vegetation of beach habitat along restinga areas.