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URI permanente desta comunidadehttps://bdc.icmbio.gov.br/handle/cecav/1401
Centro Nacional de Pesquisa e Conservação de Répteis e Anfíbios
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2 resultados
Resultados da Pesquisa
Item The agricultural transformation of Brazil’s Cerrado is influencing the diversity and distribution of tadpoles via lentification(Biodiversity and Conservation, 2024) With, Kimberly A.; Ramalho, Werther P.; McIntosh, Tanner.; Signorelli, LucianaMore than half of Brazil’s Cerrado has been converted to agricultural land use, threatening its rich biodiversity that includes > 200 anuran species, most of which have aquatic larvae and are thus doubly susceptible to the environmental impacts of agriculture. Past research has largely focused on how land-use change affects adult anurans, which ignores potential impacts on the critical larval stage. We therefore investigated how agricultural land use (250–1000 m scale) and the local pond environment affect the diversity and distribution of tadpole assemblages across the central Cerrado. Tadpole richness declined significantly with increasing cropland within 250 m of ponds and with increasing water pH in permanent ponds. Permanent ponds are more prevalent in agricultural areas where streams are impounded to provide water for irrigation and livestock, and water pH increases with increasing agriculture, likely due to the widespread use of agricultural lime in the Cerrado. Tadpole communities exhibited high beta diversity (81–86% dissimilarity), with species replacement rather than nestedness accounting for 90–97% of species differences between ponds, which was largely driven by hydroperiod. Six species accounted for 70% of the dissimilarity, with most species either more abundant or found only in temporary ponds. Increased lentification, a corollary of agricultural land use, is profoundly altering tadpole assemblages, which has consequences for overall anuran diversity in the Cerrado given that permanent ponds support a different and less-diverse larval assemblage than ephemeral wetlands. Anuran conservation in the Cerrado should therefore additionally consider maintaining or restoring wetland hydrology and native-vegetation buffers around wetlands.Item Assessing Brazilian turtles’ vulnerability BY USING species distribution models AND dispersal constraints(Biodiversity and Conservation, 2024-01-27) Pinto, Hugo Bonfim de Arruda; Valadão, Rafael Martins; Andrade, André Felipe Alves de; Batista, Flavia Regina de Queiroz; Marco Júnior, Paulo DeMost assessments of the conservation status of Brazilian turtles use the IUCN geographic range criteria performed by the Minimum Convex Polygon (MCP). This technique often leads to over- or under-estimating the geographic distribution of rare, vulnerable, or endangered species. We aimed to demonstrate that using Species Distribution Models (SDM) on the geographic range assessment of turtles could be more accurate than using the minimum polygon convex. We reduced overestimation of species’ extent of occurrence by adding dispersal constraints, which avoids under- or over-estimating the impact of threatening events. The extent of occurrence derived from MCP was 31% higher than SDM on average, ranging from 4 to 311% higher. Using remaining habitat variables, we found that habitat loss within the predicted extent of occurrence increased by 79% from 1985 to 2019, and inferred population fragmentation increased by 161%. The distribution of turtles Acanthochelys radiolata, Acanthochelys spixii, Hydromedusa maximiliani, Hydromedusa tectifera, Mesoclemmys vanderhaegei, Phrynops williamsi, and Ranacephala hogei is severely fragmented, with most of their extent of occurrence being split into patches that are unavailable to the species persistence. Our findings highlight the importance of using SDM combined with dispersal constraints, which may further benefit from future information about the dispersal capacity of turtles. Furthermore, adding environmental layers to this combination makes it possible to discuss processes affected by habitat fragmentation, such as the fragmentation of species populations, an aspect essential to evaluate population viability and local extinctions.