34 research outputs found
Birds of the Estação Ecológica de Itirapina, State of São Paulo, Brazil
O cerrado é um dos biomas mais ameaçados no mundo, apresentando algumas das maiores taxas de destruição causadas principalmente pela agropecuária. Poucos estudos têm avaliado a diversidade local de aves no cerrado, especialmente em áreas marginais desse bioma. A Estação Ecológica de Itirapina (EEI) contém um dos últimos remanescentes de campos naturais e cerrados do estado de São Paulo. Um levantamento das aves desta unidade de conservação, feito tanto por observações casuais como sistemáticas entre 1998 e 2007, e complementado por revisão de literatura, revelou que 231 espécies apresentaram ocorrência recente na área. Desse total, 38 espécies (16,4%) encontram-se na lista de espécies ameaçadas para o estado de São Paulo e/ou são endêmicas do Cerrado, um alto número quando comparado com outras áreas de cerrados paulistas ou mesmo em relação ao Brasil Central. Tal fato reforça a importância da EEI em relação à conservação da avifauna e demonstra que a mesma está mantendo sua função de conservar a biodiversidade. Adicionalmente, ao longo dos 10 anos de estudo foram detectadas várias ameaças à EEI, e neste sentido são recomendadas aqui algumas sugestões de manejo que consideramos essenciais para essa unidade de conservação manter ou mesmo aumentar sua diversidade de aves.Currently the Cerrado biome is one of the most threatened in the world because high taxes of destruction, mostly by agriculture and cattle. Few assessments of local bird diversity have been made in this biome, particularly in non core areas. The Estação Ecológica de Itirapina (EEI) maintains one of the last natural grassland savannah remnants of state of São Paulo, south-east Brazil. We conducted casual and systematic observations of birds in this reserve between 1998 and 2007, which altogether with additional literature revision yielded 231 species with recent occurrence. We report 38 species (16.4%) threatened with extinction in São Paulo and/or endemic to the Cerrado Region, an impressive result in comparison to other cerrado areas in São Paulo and even in Central Brazil. These results reinforce the importance of EEI for bird conservation and mean EEI is maintaining its function as a conservation unity. However, as a result of several menaces observed to this reserve during our ten years study, we suggest some management practices for the maintenance or even increasing of bird diversity in this reserve
Use of small Atlantic Forest fragments by birds in Southeast Brazil
Small forest fragments may play a major role in fragmented areas, but there is scarce empirical data to test this hypothesis. To understand in which context birds can use small Atlantic Forest fragments, we tested the presence of 11 bird species in 30 small fragments (4–10 ha), in a range of matrices (eucalyptus-pasture), and in different landscape configurations. The results showed that landscape composition is a good predictor for presence of birds in small fragments and their use can be further associated with matrix type. Considering the number of species, and the species Chiroxiphia caudata, we found a pattern in which models that consider the matrix composition are the most plausible. Relative importance of the variables indicates that matrix is the most important single variable among the selected species (five among eight). This suggests that small fragments are effective for increasing connectivity, mainly in landscapes with a higher percentage of permeable matrix
SURVEYING POPULATIONS OF RED-BILLED CURASSOWS (CRAX BLUMENBACHII) IN THE ATLANTIC FOREST OF BRAZIL
Threatened species are frequently difficult to monitor, leading to a lack of information for the selection of the best conservation strategies. A case in point is the Red-billed Curassow (Crax blumenbachii, Cracidae, Galliformes), whose populations have declined due to deforestation of the northern Atlantic Forest and increased poaching in the late 1960s. The species is presently absent from most forest frag- ments within its geographic range, occurring only in forest remnants on the states of Bahia and Espírito Santo, Brazil. In this study, we esti- mated encounter rates and recorded the periods of activity of the Red-billed Curassow in three large Atlantic Forest fragments in the north- eastern Brazilian state of Bahia, using line-transect sampling. The northern region of Serra do Conduru State Park (0.29 sighting/10 km) and Descobrimento National Park (0.27 sighting/10 km) presented slightly greater encounter rates of this endangered cracid, compared to the Una Biological Reserve (0.13 – 0.20 sighting/10 km). We recorded Red-billed Curassows throughout the day, mainly between 10:00–11:00 h and 14:00–17:00 h. Our study is the first step for long-term monitoring of the Red-billed Curassow. These findings serve as baseline infor- mation, which may contribute to future assessments of the conservation status and support future conservation actions for the species
Optimizing land use decision-making to sustain Brazilian agricultural profits, biodiversity and ecosystem services
AbstractDesigning landscapes that can meet human needs, while maintaining functioning ecosystems, is essential for long-term sustainability. To achieve this goal, we must better understand the trade-offs and thresholds in the provision of ecosystem services and economic returns. To this end, we integrate spatially explicit economic and biophysical models to jointly optimize agricultural profit (sugarcane production and cattle ranching), biodiversity (bird and mammal species), and freshwater quality (nitrogen, phosphorus, and sediment retention) in the Brazilian Cerrado. We generate efficiency frontiers to evaluate the economic and environmental trade-offs and map efficient combinations of agricultural land and natural habitat under varying service importance. To assess the potential impact of the Brazilian Forest Code (FC), a federal policy that aims to promote biodiversity and ecosystem services on private lands, we compare the frontiers with optimizations that mimic the habitat requirements in the region. We find significant opportunities to improve both economic and environmental outcomes relative to the current landscape. Substantial trade-offs between biodiversity and water quality exist when land use planning targets a single service, but these trade-offs can be minimized through multi-objective planning. We also detect non-linear profit-ecosystem services relationships that result in land use thresholds that coincide with the FC requirements. Further, we demonstrate that landscape-level planning can greatly improve the performance of the FC relative to traditional farm-level planning. These findings suggest that through joint planning for economic and environmental goals at a landscape-scale, Brazil's agricultural sector can expand production and meet regulatory requirements, while maintaining biodiversity and ecosystem service provision
Deforestation alters species interactions
Interspecific interactions are a major determinant of stability in ecological communities and are known to vary with biotic and abiotic conditions. Deforestation is the primary driver of the ongoing sixth mass extinction, yet its effect on species interactions remains largely unexplored. We investigate how deforestation affects species interactions using a complex systems model and a co-occurrence dataset of 363 bird species, observed across 134 sites, from 5 regions across the Brazilian Atlantic Forest totalling 27,226 interactions. Both theoretical and empirical results show that interspecific interactions vary non-monotonically with forest cover and are more positive than average in areas with higher forest cover, and to a lesser extent in highly deforested areas. Observed differences in interactions reflect both species turnover and changes in pairwise interactions. Our results point to changes in stability across the gradient of deforestation that may lead to varying community resilience to environmental perturbations
Intraspecific variation in sensitivity to habitat fragmentation is influenced by forest cover and distance to the range edge
The relative effects of habitat loss and fragmentation on biodiversity have been a topic of discussion for decades. While it is acknowledged that habitat amount can mediate the effects of habitat fragmentation, it is unclear what other factors may drive inter- and intraspecific variation in fragmentation effects and their implications for conservation. We tested whether the effects of forest fragmentation on 362 bird species' occurrence in the Atlantic Forest of Brazil are mediated by distance to geographic range edge and habitat amount, and whether these effects explain intraspecific variation across populations. Using a single binomial linear mixed effects model, we found that fragmentation had mostly negative effects on occurrence probability up to 1080 km from the species' range edge, independent of habitat amount. We also show that above this distance, fragmentation has predominantly positive effects, more accentuated in deforested landscapes. We demonstrate that fragmentation effects can be both positive and negative, indicating that different populations of the same species can respond differently depending on distance to range edge and local forest cover. Our results help clarify one of the drivers of contradictory results found in the fragmentation literature and highlight the importance of preventing habitat fragmentation for the conservation of endangered populations. Conservation initiatives should focus on minimising fragmentation closer to range edges of target species and in regions where species range edges overlap
PROTOCOLO PARA MONITORAMENTO DE COMUNIDADES DE AVES EM UNIDADES DE CONSERVAÇÃO FEDERAIS
Este protocolo de monitoramento de comunidades de aves foi construído no contexto do Programa de Monitoramento in situ da Biodiversidade em unidades de conservação federais do Instituto Chico Mendes de Conservação da Biodiversidade. As unidades de conservação federais possuem diferentes condições de gestão, relacionadas aos recursos humanos, financeiros e materiais, e que, consequentemente, influenciam sua capacidade de execução de propostas e programas ambientais. Com essa realidade em mente, foi construído um protocolo mínimo que fosse factível mesmo em unidades de conservação que não apresentassem condições ideais de estrutura e logística. Com base em uma análise sistemática, e com a finalidade de fornecer dados sobre a estrutura de comunidade de aves, o método de ponto fixo foi o selecionado para compor o protocolo por ser versátil, apresentar melhores características de custo-benefício e ser amplamente utilizado em outros projetos de monitoramento de comunidades de aves. O protocolo apresentado propõe a adoção de uma estação de amostragem constituída por 12 pontos fixos com uma distância mínima de 200 metros entre eles e raio de detecção máximo de 50 metros. Em cada unidade de conservação deverá ser implementado um mínimo de três estações de amostragem independentes, totalizando 36 pontos avaliados durante a estação reprodutiva. Esperamos que este protocolo contribua com a coleta de dados padronizada nas unidades de conservação – e até mesmo em projetos similares, e dessa maneira seja possível que os resultados desse monitoramento permitam avaliar o grau de integridade dessas unidades assim como comparar as informações entre as unidades de conservação, avaliando a efetividade do Sistema Nacional de Unidades de Conservação (SNUC)