Multiscale approach to evaluate the occupation of stingless bees in Atlantic Forest patches

Studies at multiple scales are essential to obtain a holistic view of bee conservation. For the accomplishment of these studies, the importance of analyzes that evaluate the composition of the landscape, the habitat factors and the abiotic factors must be considered. This study aimed to develop models for identification of hotspots for stingless bees in forest patches, and to address possible factors that influence the presence of native bees. The study was conducted in Salto de Pirapora - SP, a municipality composed of small fragments of Atlantic Forest. The spatial model was developed based on fragment size, core size, distance from the nearest forest patch and distance from the nearest body of water. From the spatial model, 3 hotspot forest patches (with characteristics that favor the presence of stingless bees with arboreal nesting habit) and 3 control fragments (considered fragments with unfavorable characteristics) were selected, and the presence of bees was evaluated from the occupation of artificial hives installed in the fragments. The analysis of the artificial hives showed that bees were influenced by competition for nesting sites, by predation and by precipitation. The microclimatic analyzes resulted in very variable data and did not demonstrate a significant relation to the presence of bees. Concerning the local scale, the structure of the vegetation showed great importance to the occupation of the artificial hives, with emphasis on the height and diameter of the trees where the hive was installed and the presence of shrubs and grasses as foraging resources. Bees showed preference to occupy artificial hives that were located in the patches’ core. The analysis of the surroundings of each patch was an essential factor for the development of the spatial model, demonstrating that the silviculture activity was beneficial for the presence of bees and the presence of pastures and grasslands was a negative factor. The study suggests that, for the elaboration of multiscale approaches, it is essential to evaluate not only the size of the fragment and the presence of water bodies, but also the quality of foraging (flowers) and nesting (size of trees) resources and the surroundings of the fragment. The study provided content so that the information can be extrapolated to other scenarios and encourages the conservation of the small forest patches as a strategy for the conservation of stingless bees.Não recebi financiamentoEstudos em múltiplas escalas são essenciais para que se obtenha uma visão holística para a conservação das abelhas. Para a realização destes estudos, deve-se considerar a importância de análises que avaliem tanto a composição da paisagem quanto as variáveis das manchas de habitat e os fatores abióticos. Este estudo visou, portanto, desenvolver modelos para identificação de para abelhas sem ferrão em fragmentos florestais, e abordar os possíveis fatores que influenciam a presença destas abelhas nativas. O estudo foi realizado em de Salto de Pirapora – SP, um município composto por pequenos fragmentos de Mata Atlântica. O modelo espacial foi desenvolvido com base no tamanho do fragmento, tamanho do núcleo, distância até o fragmento mais próximo e distância até o corpo d'água mais próximo. A partir do modelo foram selecionados três fragmentos hotspot (com características que favorecem a presença de abelhas sem ferrão com hábito de nidificação arbórea) e três fragmentos controle (considerados fragmentos com características desfavoráveis), e a presença de abelhas foi avaliada a partir da ocupação de abrigos artificiais instalados nos fragmentos. A análise dos abrigos artificias mostrou que as abelhas estavam sujeitas à competição por recurso de nidificação, à predação e à precipitação. As análises microclimáticas resultaram em dados muito variáveis e não demonstraram correlação significativa com a presença de abelhas. A respeito da escala local, a estrutura da vegetação demonstrou grande importância nas evidências de colonização dos abrigos artificiais, com destaque para o diâmetro e a altura das árvores onde se instalou o abrigo e a presença de arbustos e gramíneas com recursos florais para forrageamento. Houve mais evidências de colonização em abrigos que se localizavam no núcleo dos fragmentos florestais. A análise do entorno de cada fragmento foi um fator essencial para o desenvolvimento do modelo espacial, demonstrando que a atividade de silvicultura foi benéfica para a presença de abelhas sem ferrão e a presença de campo limpo foi um fator negativo. O estudo demonstrou que, para a elaboração de abordagens multiescalas, é essencial que se avalie não somente o tamanho do fragmento e a presença de corpos d’água, mas também a qualidade dos recursos de forrageamento (flores) e nidificação (tamanho das árvores) e o entorno do fragmento. O estudo fornece dados para que as informações sejam extrapoladas para outros contextos fragmentados e incentiva a conservação de pequenos fragmentos florestais como uma estratégia de conservação para abelhas sem ferrão

Amphibian Beta Diversity in the Brazilian Atlantic Forest: Contrasting the Roles of Historical Events and Contemporary Conditions at Different Spatial Scales

<div><p>Current patterns of biodiversity distribution result from a combination of historical and contemporary processes. Here, we compiled checklists of amphibian species to assess the roles of long-term climate stability (Quaternary oscillations), contemporary environmental gradients and geographical distance as determinants of change in amphibian taxonomic and phylogenetic composition in the Brazilian Atlantic Forest. We calculated beta diversity as both variation in species composition (CBD) and phylogenetic differentiation (PBD) among the assemblages. In both cases, overall beta diversity was partitioned into two basic components: species replacement and difference in species richness. Our results suggest that the CBD and PBD of amphibians are determined by spatial turnover. Geographical distance, current environmental gradients and long-term climatic conditions were complementary predictors of the variation in CBD and PBD of amphibian species. Furthermore, the turnover components between sites from different regions and between sites within the stable region were greater than between sites within the unstable region. On the other hand, the proportion of beta-diversity due to species richness difference for both CBD and PBD was higher between sites in the unstable region than between sites in the stable region. The high turnover components from CBD and PBD between sites in unstable <i>vs</i> stable regions suggest that these distinct regions have different biogeographic histories. Sites in the stable region shared distinct clades that might have led to greater diversity, whereas sites in the unstable region shared close relatives. Taken together, these results indicate that speciation, environmental filtering and limited dispersal are complementary drivers of beta-diversity of amphibian assemblages in the Brazilian Atlantic Forest.</p></div

Partition of the variance of Compositional Beta Diversity (CBD, β_jac, β_jtu and β_jne) and Phylogenetic Beta Diversity (PBD, UniFrac_Total, UniFrac_Turn and UniFrac_PD) components explained by geographical distance (Space), current environmental gradients (Environ) and long-term climatic conditions (refugia) for 44 sites in the southern range of Brazilian Atlantic Forest.

<p>Res  =  unexplained variance. “-”  =  variation explained <0.</p

Distribution of the10% highest values of annual precipitation for the current time, the two last glacial maximum period (LGM), and the intersection of the three maps.

<p>Symbols (in the intersection map) indicate the 44 sites in the southern range of Brazilian Atlantic Forest. Dark shading indicates stable regions. White circles represent sites in an unstable region (Quaternary Climatic Oscillations). White triangles represent sites in a stable region (Quaternary Climatic Stability). Abbreviations of each site as in Appendix S1 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109642#pone.0109642.s002" target="_blank">File S1</a>.</p

Standardized effect size (SES) values for phylogenetic beta diversity (PBD, A = UniFrac_Total, B = UniFrac_Turn and C = UniFrac_PD) components among 44 sites in Brazilian Atlantic Forest.

<p>Values between dashed lines indicate that PBD components have no difference with respect to null expectation. Symbol colors indicate the region where the sites occur in the southern range of Brazilian Atlantic Forest. Black circles indicate SES between sites within stable region (Quaternary Climatic Stability). Gray circles indicates SES between sites within unstable region (Quaternary Climatic Oscillations). White circles indicate SES between unstable and stable sites (different regions).</p