The effect of the adjacent non-forested environment on the forest near the edge, edge influence (EI), is an important impact in fragmented landscapes and is believed to vary with factors such as forest structure and edge contrast. In order to improve our understanding of the factors governing the variability in EI, we studied microclimate and vegetation at cerrado edges surrounded by variable land uses in southeastern Brazil, a system with both forest and savanna fragments. We determined the significance, magnitude and distance of EI on microclimate, vegetation structure and grass biomass which we measured along five transects perpendicular to fourteen edges in forest or savanna next to different land uses. We introduce a quantitative measure of edge contrast that considers land uses at different distances from the same edge (e.g., a firebreak between a forest edge and a plantation) and verified whether edge contrast is correlated with EI in this system. Notwithstanding the large variation in EI among variables and study sites, there were some similarities in the patterns of EI between forest and savanna edges. Edge contrast was successfully quantified by our measure but was only correlated with EI on moisture and grass biomass. Our results point to the high variability in EI within a region. Our quantitative measure of edge contrast may be useful in explaining variability in EI. However, much unexplained variation remains in the highly fragmented cerrado system which is affected by EI in both forest and savanna fragments.
particularly in landscapes with a pasture matrix. However, this land use disrupts the species composition of communities, indicating that communities located in cerrado and pasture have a distinct species composition, and that both communities are afected by edge distance. Thus, anthropogenic land uses may severely afect dung beetles, and this impact can extend to communities located in cerrado remnants as well as to those in matrices, with possible consequences for ecological processes such as decomposition and nutrient cycling.
Habitat loss represents one of the main threats to tropical forests, which have reached extremely high rates of species extinction. Forest loss negatively impacts biodiversity, affecting ecological (e.g., seed dispersal) and genetic (e.g., genetic diversity and structure) processes. Therefore, understanding how deforestation influences genetic resources is strategic for conservation. Our aim was to empirically evaluate the effects of landscape‐scale forest reduction on the spatial genetic structure and gene flow of Euterpe edulis Mart (Arecaceae), a palm tree considered a keystone resource for many vertebrate species. This study was carried out in nine forest remnants in the Atlantic Forest, northeastern Brazil, located in landscapes within a gradient of forest cover (19–83%). We collected leaves of 246 adults and 271 seedlings and performed genotyping using microsatellite markers. Our results showed that the palm populations had low spatial genetic structure, indicating that forest reduction did not influence this genetic parameter for neither seedlings nor adults. However, forest loss decreased the gene flow distance, which may negatively affect the genetic diversity of future generations by increasing the risk of local extinction of this keystone palm. For efficient strategies of genetic variability conservation and maintenance of gene flow in E. edulis, we recommend the maintenance of landscapes with intermediary to high levels of forest cover, that is, forest cover above 40%.
Maintaining connectivity is one of the main challenges for biodiversity conservation world-wide. Ecological corridors are important to maintain landscape connectivity, but their efficiency depends on landscape patterns and species responses at different spatial extents and landscape contexts. 2. We developed a new ecologically oriented free software package, LandScape Corridors (LSCORRIDORS), to improve ecological corridor design by considering biodiversity responses to landscape attributes at a variety of spatial extents. LandScape Corridors considers stochastic variation, species perception and landscape influence on organisms in the design of ecological corridors. In addition to the least cost path algorithm, we propose four different methods for the simulation of multiple-path functional ecological corridors. One method uses the information for each pixel separately, whereas the three other methods permit corridor simulation considering the landscape context at different spatial extents. 3. LandScape Corridors permits to simulate corridors for species with different requirements and considers that different species perceive and respond to the surrounding landscape in different ways, as many species may choose to move through areas that may not be the most permeable ones in the landscape. Two parameters in LSCORRIDORS modulate the stochasticity in corridors simulations. The first parameter is the level of variability added to the input resistance map in each simulation, resulting in more variable and spatially spread-out corridors. The other parameter is the spatial extent that may influence each pixel; larger extents result in larger spatial zones affecting each pixel during corridors simulations. In addition, when considering spatial influence, the simulations may be performed for species highly, medially or less sensitive to habitat quality. 4. Some currently available software are not free or depend on a paid GIS software to work. In addition, some software do not support large matrices in their simulations, limiting their use. LandScape Corridors is designed to deal with large rasters, is based on strictly freeware software, and is freely available online. This allows the users to implement new methods for modelling multi-scale and ecologically based corridors. 5. LandScape Corridors is a potential tool for the identification of protected areas, as corridor simulation considers species movement and landscape connectivity, essential characteristics to aid in large-scale biodiversity conservation, especially in anthropogenic landscapes. LandScape Corridors provides what we may call a zone for conservation, showing a set of connected areas in the landscape which may be ordered according to their potential for ecological corridors or which may be used as an aid for conservation strategies or ecological restoration projects.
RESUMO: O objetivo deste trabalho foi realizar um estudo exploratório sobre as ações de educação ambiental desenvolvidas em unidades de conservação (UCs) brasileiras em relação a público, parcerias, linha pedagógica, objetivos, atividades, temas, avaliação e documentos de referência. Além disso, analisamos uma possível influência do Programa Nacional de Educação Ambiental (ProNEA) nessas práticas. Utilizamos dados de 56 UCs brasileiras coletados em questionário distribuído em 2007. Analisamos o total de UCs e dois grupos distintos: as que citaram e as que não citaram o ProNEA como referência. As ações educativas apresentam alguns princípios das novas tendências da educação ambiental e das políticas públicas elaboradas nos últimos anos no Brasil. Concluímos que embora uma política pública de larga escala, como o ProNEA, seja importante para orientar as mudanças desejadas, não é suficiente para que essas mudanças sejam incorporadas às práticas educativas. Palavras-chave:
Background: Plant community assemblage is influenced by many factors, including soil characteristics and the arrival of diaspores from surrounding areas. These factors may be especially important in transition areas, leading to spatial gradients in the plant community. Methods: This study was performed in the understorey of an abandoned Eucalyptus grandis W. Hill ex Maiden plantation between a savanna and a forest, 490 m apart, in south-eastern Brazil. This study assessed whether the spatial variation in several variables related to the understorey's structure and composition is best described by linear or non-linear (quadratic) models. The linear model would indicate a gradient between the two vegetation types, whereas the quadratic model would indicate a stronger effect of the plantation's edges. Results: There was a gradient in species composition between the two edges of the plantation. Mean vegetation height was greatest at the savanna edge and lowest in the centre of the plantation. The total number of individuals per plot and the phylogenetic diversity decreased with distance from the savanna edge. Different patterns were observed for different dispersal syndromes, with animal dispersal being more common at the savanna edge, wind dispersal in the centre of the plantation and self dispersal at the forest edge. Conclusions: The greater number of individuals at the savanna edge may indicate that dispersal and arrival of diaspores are the most important factors influencing community structure and composition of the understorey of this abandoned E. grandis plantation, with most propagules coming from the savanna area. The smaller vegetation height in the centre of the fragment may also indicate older colonisation at the edges. Therefore, in addition to highlighting the recovery potential of undergrowth beneath abandoned Eucalyptus spp. plantations, these results show that this recovery is spatially heterogeneous and that dispersal plays a large role in it. This should be taken into account in restoration projects. The authors recommend careful consideration before removing regenerating Eucalyptus spp. trees as part of the site restoration. Instead the focus should be on the recovery potential of the undergrowth, with gradual removal of Eucalyptus trees, if necessary.
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