Efeito da área, da quantidade de habitat e do tipo de matriz sobre dieta de gato-maracajá (Leopardus wiedii)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da fragmentação sobre a persistência de anfíbios anuros (Amphibia: Anura) na Mata Atlântica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da desconexão de habitat na diversidade funcional de anfíbios anuros (Amphibia: Anura) na Mata Atlântica

Amphibian populations worldwide have been suffering declines generated by habitat degradation, loss, fragmentation and habitat split. With habitat loss and fragmentation in the landscape comes habitat split, which is the separation between the adult anuran habitat and breeding sites, forcing individuals to move through matrix during breeding seasons. Thus, habitat split increases the chance of extinction of amphibians with aquatic larval development and acts as a filter in the selection of species having great influence on species richness and community structure. The use of functional diversity allows us to consider the identity and characteristics of each species to understand the effects of fragmentation processes. The objective of this study was to estimate the effects of habitat split, as well as habitat loss in the landscape, on amphibians functional diversity (FD) and species richness (S). We selected 26 landscapes from a database with anuran surveys of Brazilian Atlantic Forest. For each landscape we calculated DF, S and landscape metrics at multiple scales. To calculate the DF we considered traits that influenced species use and persistence in the landscape. We refined maps of forest remnants and water bodies for metrics calculation. To relate DF and S (response variables) to landscape variables (explanatory variables), we used a model selection approach, fitting generalized linear models (GLMS) and making your selection with AICc. We compared the effect of model absence and models with habitat split, habitat amount and habitat connectivity effects, as well as their interaction. The most plausible models for S were the sum and interaction between habitat split in 7.5 km scale. For anurans with terrestrial development, habitat amount was the only plausible explanatory variable, in the 5 km scale. For anurans with aquatic larvae habitat amount in larger scales and the addition of habitat amount and habitat split were plausible...

Efeito do gradiente interior-borda-matriz, e do tipo de matriz sobre a entomofaúna edáfica em fragmentos de cerrado

edge effect. Thus, under the influence of the adjacent matrix, fragments undergo microclimatic alterations that accentuate changes in species composition and community structure. In order to better understand edge and matrix effects on the richness and abundance of edaphic arthropods, this study assessed: (a) the difference between habitat (fragment) and non-habitat (matrix); (b) whether there is a continuous interior-edge-matrix gradient; and (c) the difference between matrices for arthropod orders richness and abundance. We selected 15 landscapes, 5 of which contained a cerrado fragment surrounded by sugarcane cultivation, 5 with a cerrado fragment within eucalyptus and 5 with a cerrado fragment within pasture. In each landscape the soil fauna was collected along with the soil and then extracted with the aid of the modified Berlese-Tullgren funnel. We chose the orders Coleoptera, Collembola, Mesostigmata and Oribatida for analysis, and after separation of the individuals we used model selection analysis via AIC. The model type fragment x matrix was the most likely to explain richness, total and relative abundances of the four orders (wAICc between 0,6623 and 1,0). The model of edge distance (edge effect) was plausible to total abundance and relative abundance of Mesostigmata order (wAICc=0,2717 and 0,186). Local environmental variables (soil texture, temperature and relative humidity), and fragment size were also measured to avoid confounding factors and were not presented as plausible models to explain the patterns. So edaphic arthropods, despite protecting themselves under the ground, are extremely sensitive to fragmentation, even with the replacement of natural habitat by agricultural use, such as sugarcane, pasture and eucalyptus. This group should be studied environmental impact assessments because provides important ecosystem se ravincde s inacnludd eisd ainn efficient bio-indicator

Landscape-Genetic Analysis of Population Structure in the Texas Gray Fox Oral Rabies Vaccination Zone

In west-central Texas, USA, abatement efforts for the gray fox (Urocyon cinereoargenteus) rabies epizootic illustrate the difficulties inherent in large-scale management of wildlife disease. The rabies epizootic has been managed through a cooperative oral rabies vaccination program (ORV) since 1996. Millions of edible baits containing a rabies vaccine have been distributed annually in a 16-km to 24-km zone around the perimeter of the epizootic, which encompasses a geographic area >4 x 105 km2. The ORV program successfully halted expansion of the epizootic into metropolitan areas but has not achieved the ultimate goal of eradication. Rabies activity in gray fox continues to occur periodically outside the ORV zone, preventing ORV zone contraction and dissipation of the epizootic. We employed a landscape-genetic approach to assess gray fox population structure and dispersal in the affected area, with the aim of assisting rabies management efforts. No unique genetic clusters or population boundaries were detected. Instead, foxes were weakly structured over the entire region in an isolation by distance pattern. Local subpopulations appeared to be genetically non-independent over distances >30 km, implying that long-distance movements or dispersal may have been common in the region. We concluded that gray foxes in west-central Texas have a high potential for long-distance rabies virus trafficking. Thus, a 16-km to 24-km ORV zone may be too narrow to contain the fox rabies epizootic. Continued expansion of the ORV zone, although costly, may be critical to the long-term goal of eliminating the Texas fox rabies virus variant from the United States.

Landscape Genetics of Raccoons (Procyon lotor) Associated with Ridges and Valleys of Pennsylvania: Implications for Oral Rabies Vaccination Programs

Raccoons are the reservoir for the raccoon rabies virus variant in the United States. To combat this threat, oral rabies vaccination (ORV) programs are conducted in many eastern states. To aid in these efforts, the genetic structure of raccoons (Procyon lotor) was assessed in southwestern Pennsylvania to determine if select geographic features (i.e., ridges and valleys) serve as corridors or hindrances to raccoon gene flow (e.g., movement) and, therefore, rabies virus trafficking in this physiographic region. Raccoon DNA samples (n = 185) were collected from one ridge site and two adjacent valleys in southwestern Pennsylvania (Westmoreland, Cambria, Fayette, and Somerset counties). Raccoon genetic structure within and among these study sites was characterized at nine microsatellite loci. Results indicated that there was little population subdivision among any sites sampled. Furthermore, analyses using a model-based clustering approach indicated one essentially panmictic population was present among all the raccoons sampled over a reasonably broad geographic area (e.g., sites up to 36 km apart). However, a signature of isolation by distance was detected, suggesting that widths of ORV zones are critical for success. Combined, these data indicate that geographic features within this landscape influence raccoon gene flow only to a limited extent, suggesting that ridges of this physiographic system will not provide substantial long-term natural barriers to rabies virus trafficking. These results may be of value for future ORV efforts in Pennsylvania and other eastern states with similar landscapes.

Efeito da área, da quantidade de habitat e do tipo de matriz sobre dieta de gato-maracajá (Leopardus wiedii)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da fragmentação sobre a persistência de anfíbios anuros (Amphibia: Anura) na Mata Atlântica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da desconexão de habitat na diversidade funcional de anfíbios anuros (Amphibia: Anura) na Mata Atlântica

Amphibian populations worldwide have been suffering declines generated by habitat degradation, loss, fragmentation and habitat split. With habitat loss and fragmentation in the landscape comes habitat split, which is the separation between the adult anuran habitat and breeding sites, forcing individuals to move through matrix during breeding seasons. Thus, habitat split increases the chance of extinction of amphibians with aquatic larval development and acts as a filter in the selection of species having great influence on species richness and community structure. The use of functional diversity allows us to consider the identity and characteristics of each species to understand the effects of fragmentation processes. The objective of this study was to estimate the effects of habitat split, as well as habitat loss in the landscape, on amphibians functional diversity (FD) and species richness (S). We selected 26 landscapes from a database with anuran surveys of Brazilian Atlantic Forest. For each landscape we calculated DF, S and landscape metrics at multiple scales. To calculate the DF we considered traits that influenced species use and persistence in the landscape. We refined maps of forest remnants and water bodies for metrics calculation. To relate DF and S (response variables) to landscape variables (explanatory variables), we used a model selection approach, fitting generalized linear models (GLMS) and making your selection with AICc. We compared the effect of model absence and models with habitat split, habitat amount and habitat connectivity effects, as well as their interaction. The most plausible models for S were the sum and interaction between habitat split in 7.5 km scale. For anurans with terrestrial development, habitat amount was the only plausible explanatory variable, in the 5 km scale. For anurans with aquatic larvae habitat amount in larger scales and the addition of habitat amount and habitat split were plausible...

Efeito do gradiente interior-borda-matriz, e do tipo de matriz sobre a entomofaúna edáfica em fragmentos de cerrado

edge effect. Thus, under the influence of the adjacent matrix, fragments undergo microclimatic alterations that accentuate changes in species composition and community structure. In order to better understand edge and matrix effects on the richness and abundance of edaphic arthropods, this study assessed: (a) the difference between habitat (fragment) and non-habitat (matrix); (b) whether there is a continuous interior-edge-matrix gradient; and (c) the difference between matrices for arthropod orders richness and abundance. We selected 15 landscapes, 5 of which contained a cerrado fragment surrounded by sugarcane cultivation, 5 with a cerrado fragment within eucalyptus and 5 with a cerrado fragment within pasture. In each landscape the soil fauna was collected along with the soil and then extracted with the aid of the modified Berlese-Tullgren funnel. We chose the orders Coleoptera, Collembola, Mesostigmata and Oribatida for analysis, and after separation of the individuals we used model selection analysis via AIC. The model type fragment x matrix was the most likely to explain richness, total and relative abundances of the four orders (wAICc between 0,6623 and 1,0). The model of edge distance (edge effect) was plausible to total abundance and relative abundance of Mesostigmata order (wAICc=0,2717 and 0,186). Local environmental variables (soil texture, temperature and relative humidity), and fragment size were also measured to avoid confounding factors and were not presented as plausible models to explain the patterns. So edaphic arthropods, despite protecting themselves under the ground, are extremely sensitive to fragmentation, even with the replacement of natural habitat by agricultural use, such as sugarcane, pasture and eucalyptus. This group should be studied environmental impact assessments because provides important ecosystem se ravincde s inacnludd eisd ainn efficient bio-indicator

Influence of landscape evolution on the distribution of floristic patterns in northern Amazonia revealed by delta 13C data

The Amazonian lowlands include large patches of open vegetation which contrast sharply with the rainforest, and the origin of these patches has been debated. This study focuses on a large area of open vegetation in northern Brazil, where d13C and, in some instances, C/N analyses of the organic matter preserved in late Quaternary sediments were used to achieve floristic reconstructions over time. The main goal was to determine when the modern open vegetation started to develop in this area. The variability in d13C data derived from nine cores ranges from -32.2 to -19.6 parts per thousand, but with nearly 60% of data above -26.5 parts per thousand. The most enriched values were detected only in ecotone and open vegetated areas. The development of open vegetation communities was asynchronous, varying between estimated ages of 6400 and 3000 cal a BP. This suggests that the origin of the studied patches of open vegetation might be linked to sedimentary dynamics of a late Quaternary megafan system. As sedimentation ended, this vegetation type became established over the megafan surface. In addition, the data presented here show that the presence of C4 plants must be used carefully as a proxy to interpret dry paleoclimatic episodes in Amazonian areas. Copyright (c) 2012 John Wiley & Sons, Ltd.

Landscape changes in Serra do Japi: legal protection or scientific expectation?

The creation of new legally protected areas brings many conflicts that distance the real landscape from the expected according to environmental law or conservation researchers. In this study, we mapped and compared the changes in Serra da Japi (Sao Paulo State, Brazil) throughout 40 years with scenarios of legal protection and scientific expectation on forest conservation, to evaluate the distance between them. This may allow us to infer the direction of historical changes and assist in the debate among decision makers. The results showed that most legal requirements on forest protection in the current landscape have been met. The 1960s was the period when the forest cover was closest to the desirable conservation stage. Although the Serra do Japi has maintained large areas of forests during the entire study period, human interference increased with the expansion of reforestation and urban areas, and access roads were identified as a primary potential driving forces of change. In addition, habitat loss was observed in the landscape, which can represent the first phase of a sequence of modifications detrimental to the environmental conservation of this protected area, including decision changes to land use. In conclusion, the changes evolved toward conservation expectations, but not toward the forest configuration of scientific expectation.

Litterfall and leaf decomposition in forest fragments under different successional phases on the Atlantic Plateau of the state of Sao Paulo, Brazil

Litterfall and litter decomposition are vital processes in tropical forests because they regulate nutrient cycling. Nutrient cycling can be altered by forest fragmentation. The Atlantic Forest is one of the most threatened biomes in the world due to human occupation over the last 500 years. This scenario has resulted in fragments of different size, age and regeneration phase. To investigate differences in litterfall and leaf decomposition between forest successional phases, we compared six forest fragments at three different successional phases and an area of mature forest on the Atlantic Plateau of Sao Paulo, Brazil. We sampled litter monthly from November 2008 to October 2009. We used litterbags to calculate leaf decomposition rate of an exotic species, Tipuana tipu (Fabaceae), over the same period litter sampling was performed. Litterfall was higher in the earliest successional area. This pattern may be related to the structural properties of the forest fragments, especially the higher abundance of pioneer species, which have higher productivity and are typical of early successional areas. However, we have not found significant differences in the decomposition rates between the studied areas, which may be caused by rapid stabilization of the decomposition environment (combined effect of microclimatic conditions and the decomposers activities). This result indicates that the leaf decomposition process have already been restored to levels observed in mature forests after a few decades of regeneration, although litterfall has not been entirely restored. This study emphasizes the importance of secondary forests for restoration of ecosystem processes on a regional scale.

Unraveling the drivers of community dissimilarity and species extinction in fragmented landscapes

Communities in fragmented landscapes are often assumed to be structured by species extinction due to habitat loss, which has led to extensive use of the species-area relationship (SAR) in fragmentation studies. However, the use of the SAR presupposes that habitat loss leads species to extinction but does not allow for extinction to be offset by colonization of disturbed-habitat specialists. Moreover, the use of SAR assumes that species richness is a good proxy of community changes in fragmented landscapes. Here, we assessed how communities dwelling in fragmented landscapes are influenced by habitat loss at multiple scales; then we estimated the ability of models ruled by SAR and by species turnover in successfully predicting changes in community composition, and asked whether species richness is indeed an informative community metric. To address these issues, we used a data set consisting of 140 bird species sampled in 65 patches, from six landscapes with different proportions of forest cover in the Atlantic Forest of Brazil. We compared empirical patterns against simulations of over 8 million communities structured by different magnitudes of the power-law SAR and with species-specific rules to assign species to sites. Empirical results showed that, while bird community composition was strongly influenced by habitat loss at the patch and landscape scale, species richness remained largely unaffected. Modeling results revealed that the compositional changes observed in the Atlantic Forest bird metacommunity were only matched by models with either unrealistic magnitudes of the SAR or by models ruled by species turnover, akin to what would be observed along natural gradients. We show that, in the presence of such compositional turnover, species richness is poorly correlated with species extinction, and z values of the SAR strongly underestimate the effects of habitat loss. We suggest that the observed compositional changes are driven by each species reaching its individual extinction threshold: either a threshold of forest cover for species that disappear with habitat loss, or of matrix cover for species that benefit from habitat loss.

DNA fragmentation by gamma radiation and electron beams using atomic force microscopy

Double-stranded pBS plasmid DNA was irradiated with gamma rays at doses ranging from 1 to 12 kGy and electron beams from 1 to 10 kGy. Fragment-size distributions were determined by direct visualization, using atomic force microscopy with nanometer-resolution operating in non-tapping mode, combined with an improved methodology. The fragment distributions from irradiation with gamma rays revealed discrete-like patterns at all doses, suggesting that these patterns are modulated by the base pair composition of the plasmid. Irradiation with electron beams, at very high dose rates, generated continuous distributions of highly shattered DNA fragments, similar to results at much lower dose rates found in the literature. Altogether, these results indicate that AFM could supplement traditional methods for high-resolution measurements of radiation damage to DNA, while providing new and relevant information.