Ecologia reprodutiva e análise de viabilidade de uma população do cágado Hydromedusa maximiliani (Testudines, Chelidae) no Parque Estadual Carlos Botelho / Reproduction ecology and population viability analysis of the neotropical freshwater turtle Hydromedusa maximiliani (Testudines, Chelidae) at the Parque Estadual Carlos Botelho, São Paulo, Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The reproductive strategies of Hydromedusa maximiliani at the Carlos Botelho State Park, SP, was verified by X-ray in females and juveniles between September 2007 and December 2008. Throughout the study two reproductive seasons were detected, both beginning in September. From a total of 33 X-rayed females, only 19 showed eggs, and three of them showed eggs in the two reproductive seasons. Clutch size varied from 1 to 3 eggs, but only one female presented one egg and another female presented three eggs. Clutch volume was 22128.01 ± 4939.8 mm³ (10493.422136.12 mm³; N = 44). Female body size was positively correlated to clutch volume, a pattern usually detected in chelonians. Reproductive information acquired in the present study together with population data available for H. maximiliani in the study site makes it possible a population viability analysis using the software VORTEX (version 9.92). A principal scenario (Real Population) was created based on life-history data collected throughout 10 years. In order to compare the protected area with an unprotected hypothetical area regarding the persistence of the population, this scenario was modified by altering some variables (10% increasing of mortality rate, 10% increasing of inbreeding depression, decreasing of carrying capacity), which generates a scenario named Hypothetical Isolated Population. Results were compared and sensitivity tests were carried out to verify the influence of variation in mortality ratio, catastrophes and inbreeding depression. There was a significant difference between the two scenarios (p = 0.0005). The extinction risk was 31% for Real Population and 90% for Hypothetical Isolated Population. The sensitivity analysis indicated that mortality ratio, deforestation, forest fires and inbreeding depression strongly influence the population survival. Long-term studies and biological information on species inhabiting areas subjected to anthropogenic impacts, like the Atlantic Rainforest, are vital to conservation actions, since they make it possible population viability analyses and the design of management strategies to threatened populations.

ASSUNTO(S)

animal reproduction. threatened animals dinâmica de populações cágado freshwater turtle chelidae population dynamics chelidae reprodução animal. animais em extinção

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