Diversidade e conservação de quelônios no estado do Tocantins: uma análise das lacunas de conhecimento de ocorrência e a indicação de áreas prioritárias para conservação

Abstract

Testudines originated in the Triassic Period and, to the present day, exhibit relatively few morphological changes. They are of paramount importance to ecosystems because they contribute to the maintenance of biogeochemical cycles. However, impacts caused by human activities have been emerging as a major threat to chelonian populations. Of the 365 species recognized worldwide, more than half are classified as threatened with extinction. In Brazil, 40 species are recognized, making the country the third richest in chelonian diversity. Of these, 9 species are recorded in the state. This dissertation aimed to analyze the chelonians recorded in the state of Tocantins, determining the current species diversity, their areas of occurrence, and the knowledge gaps regarding geographic distribution, as well as developing a strategic approach to identify priority areas for species protection in the state. To achieve these objectives, we employed three methodological components: (1) compilation of records made up to 2009 and acquisition of new records from 2010 to 2023; searches in the technical– scientific literature; queries to platforms on Brazilian biodiversity; and requests for records from collections and museums; (2) review of a technical report containing information from the Projeto Quelônios da Amazônia (Amazon Chelonian Project; PQA); and (3) identification of priority areas for chelonian conservation in the state of Tocantins through a multicriteria analysis. We assembled 700 chelonian occurrence records for the state of Tocantins: 195 compiled through 2009 and 505 obtained between 2010 and 2023, totaling 10 chelonian species. Sampling effort indicated the potential occurrence of 11 species, and percentages of 69.44% and 96.16% of the area (depending on the spatial criterion applied) remain unsampled for chelonians when using the requirement of the presence of at least four species. Analysis of PQA areas was based on sites for which data and information were available. The scores obtained for these sites exceeded the threshold considered “high importance,” highlighting the effectiveness of the projects in defining geographic limits and sampling populations of the protected species. Areas outside the program’s scope lack organized data and information sufficient for evaluation under the criteria applied. The prioritization analysis of hydrographic regions in Tocantins yielded total scores ranging from 466 to 734 points. Elevated total scores were driven primarily by the socioeconomic factor, followed by the logistical factor; the ecological factor exerted the least influence. This study represents an important advance in knowledge of chelonian diversity in Tocantins and opens opportunities for new research. It is essential to encourage scientific studies directed at understanding species distributions and nesting sites. Finally, the analysis conducted here—focused on the hydrographic regions proposed for Tocantins—showed that chelonian protection in the state cannot rely solely on biological attributes, underscoring the need to incorporate logistical and socioeconomic factors into area-prioritization analyses.