Dinâmica de populações e metapopulações de Mesoclemmys vanderhaegei (Testudines: Chelidae) na bacia do alto rio Paraguai, Brasil

Abstract

This study aimed to assess the population structure and the metapopulation of Mesoclemmys vanderhaegei an Neotropical water turtle in the Upper Rio Paraguay basin, between November 2010 and August 2013 in two federal conservation units (Parque Nacional da Chapada dos Guimarães, PNCG; and Serra das Araras ecological station, EESA). We evaluated the population in relation to the capture and recapture rates, density, ratio, sexual dimorphism, survival, recruitment and metapopulation dynamics. As well as the assess the probability of survival and the annual recruitment rates in order to evaluation and understanding of the metapopulation dynamics of M. vanderhaegei at three spatial scales. For the population analyses we used the method of capture-mark-recapture over nine sampling period. We captured 300 individuals (77 PNCG and 223 EESA) and 343 recaptured in the two protected areas. Recapture rates were higher when compared to other studies, and the highest density was recorded in lentic waterbody. The sex ratio was biased in EESA, biased for females. Dimorphism was detected in seven morphological variables out of 34, including variables related to the individuals size, bridge, head and tail. Both populations showed little growth rates above 1, indicating slow growth, and low probabilities of survival when compared to other species of turtles, mainly related to species that do not suffer anthropic pressure. Metapopulation dynamics analysis showed that the rescue effect model was the most that influenced the structure of metapopulations with the variable occupation being the largest predictor of extinction and colonization in the three spatial scales analyzed.