Ecologia e conservação de Podocnemis expansa (Testudines, Podocnemididae) no Médio Tapajós

Abstract

P. expansa is the largest neotropical freshwater chelonian species and largest geographical distribution, categorized as low-endangered and conservation-dependent species on the IUCN list. In this Thesis, we start a discussion about the relationship between traditional people and the wildlife management in Brazil, how the legal frameworks that conduct the topic are underused and what are the prospects for the future of the management and conservation of this specie. We investigated the P. expansa population in the Middle Tapajós region between 2013 and 2019, addressing its reproductive ecology, population structure, capture, consumption and trade. We collected biometric data from 144 females and their eggs and nests. We found a significant positive correlation between female and eggs amount and size, but not with nest measurements. Female size showed a significantly positive correlation with hatching rate, as well as nest initial height, nest height in relation to river level and substrate with predominance of coarse sand. The Tapajós River level and substrate with predominance of fine sand showed a significant negative correlation with the hatching rate. Through experimental captures we captured 969 individuals, with a male-biased sex ratio was 5.83:1 . The total biomass obtained in these captures was 4.850,8 kg. The estimated size of the population of P. expansa varied between 296.679 and 319.084 individuals, and estimated biomass was between 1 .492,1 and 1 .604,8 tons. We applied 4.404 interviews, in which we recorded 193 captures, with 658 chelonians captured, corresponding to 3 .417 kg. The average capture frequency was 6,42 in the dry season and 2,48 in the high season. Long-hook and “camurim” were the most used techniques, with most captures for consumption. We found a high correlation between capture and distance traveled to capture, distance to the Monte Cristo “Tabuleiro” and the monthly quota of the Tapajós River. At the same time, we investigated P. expansa and P. unifilis consumption, that differed between urban and rural areas. The P. expansa and P. unifilis commercialized values and their eggs were higher in urban areas than in rural areas. We conclude that it is necessary to continuous monitoring of P. expansa reproduction and population dynamics, and that sustainable community management can be a viable alternative for conservation, food security and income generation.