Influência das mudanças climáticas sobre a produção de ninhos e filhotes de quelônios (Podocnemis expansa, Schweigger, 1812, Podocnemis Unifilis, Troschel, 1848; e Podocnemis sextuberculata, Cornalia, 1849) em áreas de manejo comunitário no Médio Rio Amazonas

Abstract

Chelonians have always been an important source of protein for riverside populations. Extreme climatic events that have occurred in the Amazon over the past two decades may be influencing the biological behavioral changes of certain chelonians species, such as the Amazon River turtle (Podocnemis expansa). The objective of this study was to analyze possible relationships between reproductive parameters (number of nests, hatching rate, number of hatchlings) of Podocnemis expansa, P. unifilis, and P. sextuberculata with climatic variations at nesting sites in Barreirinha, Itacoatiara, Parintins, and Nhamundá-AM in the middle Amazon River region. To do this, we used rainfall (mm), water level (cm), and temperature data from INMET (National Institute of Meteorology) and ANA (National Water Agency), along with reproductive databases (daily number of nests/year and number of hatchlings/year) of the studied species, collected by volunteers from the Pé-de-Pincha Program from 2000 to 2024. We performed descriptive statistical analysis (mean, standard deviation, maximum, and minimum) and normality tests for all evaluated variables. Spearman correlation tests were conducted between the analyzed parameters, and when significant, linear regression tests were applied. Using Generalized Linear Models (GLM), we found that the number of turtle and tracajá nests was highly correlated with river levels during droughts and floods (p = 0.92 and 0.98). For tracajás, very rainy summers influenced a reduction in hatching (P < 0.01; R² = 68%). Therefore, the number of turtle and iaçá nests was influenced by the river's minimum level: the lower the river level (severe droughts), the greater the number of nests and hatchling production for turtles and iaçás. The number of tracajá nests was influenced by the river’s minimum level: the higher the minimum river level (milder summers and droughts), the greater the tendency for more nests and hatchlings of tracajás. Turtles, followed by iaçás, appear to be more sensitive to variations in climatic factors such as higher temperatures and more severe river droughts (lower minimum levels) than tracajás. Due to annual climate changes, studies that provide information on biological changes in turtles are crucial for wildlife management actions.