Livros e Publicações
URI permanente para esta coleçãohttps://bdc.icmbio.gov.br/handle/cecav/1481
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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.Item Vulnerability of Cerrado threatened mammals(Biodiversity and Conservation, 2020) Marco Jr, Paulo De; Villén, Sara; Mendes, Poliana; Nóbrega, Caroline; Cortes, Lara; Castro, Tiago; Souza, RodrigoSpecies vulnerability is defined based on their exposition, sensitivity and adaptive capacity to a given impact. Considering limitations to estimate the sensitivity component, we developed a framework integrating the knowledge on ecological niche models and extinction thresholds, generating species sensitivity scenarios at the landscape scale. Our aim was to assess species and landscape vulnerability for threatened mammal species from the Brazilian Cerrado by considering seven types of human-impacts and climatic suitability. We assumed that climatic-suitable landscapes with less than 50% of remaining natural vegetation are not suitable for species, while in landscapes with 50–60% of remaining natural vegetation, populations are highly vulnerable. We found a spatial match between climatic-suitable areas and highly-impacted landscape (< 50% of remaining vegetation), specifically in southern Cerrado. We attribute this result to two main reasons: (1) similar characteristics affecting both suitability for species and human activities; and (2) highly impacted landscapes are likely to shelter threatened species. Vulnerable cells, with 50–60% of remaining vegetation, were distributed throughout Cerrado, meaning that there is no spatial bias within their distribution. Range-restricted species exhibited higher variability in vulnerability compared to widely-distributed species, what could be explained by human occupation being spatially clumped. Agriculture is the major impact affecting highly-impacted landscapes (< 50% of remaining vegetation), transport infra-structure has higher impact on vulnerable landscapes. We believe that our approach can be easily applied for assessing species and landscape vulnerability in many ecological domains by adapting extinction thresholds according to the focus taxon.