a b s t r a c tLandscape changes can lead to bee species loss, what impairs proper landscape level pollination processes, impacting both nature conservation and human welfare. Although landscape heterogeneity can rescue bee communities from collapsing, these insects seem sensitive to reduced functional connectivity, hindering pollen transfer among plants. Our objective was to verify which of these two factors, landscape heterogeneity or functional connectivity, can better explain variations of bee abundance and richness in a fragmented Atlantic Forest region. We sampled flower-visiting bees in 12 landscapes with varying heterogeneity and functional connectivity measured using a Functional Ecological Corridors framework. Both richness and abundance were affected by landscape factors, reaching its highest levels at intermediate levels of functional connectivity in highly heterogeneous landscapes, indicating the existence of strong regime shifts in the system. In low-forested landscapes, conservation actions for pollinating bees should focus on implementing diversified environments with high quality which are interspersed among each other and with native vegetation.
Context Loss of natural habitat can isolate pollinator populations and negatively affect sexual reproduction of animal-pollinated plants.Objective We evaluated how the loss of natural forest affects pollinator diversity in the understory of the Atlantic Rainforest in Northeastern Brazil. Methods We focused on bees, the main group of pollinators for angiosperms. We assessed how changes in forest cover at regional (36 km 2 ) and local (0.36 km 2 ) scales affect bee richness and abundance. Results We sampled 492 bees from 59 species, of which 58 % were above ground nesting species and 73 % exhibited some level of sociality. Our results show that the loss of forest had negative effects on understory bee abundance, which was particularly accentuated for species that nest above ground. However, for social bees the effect of changes in forest cover at a local scale depended on regional forest cover, negative effects being only detected when landscapes had at least 35 % of forest. For bee richness, the null model was among the best models bringing considerable uncertainty about landscape effects on bee richness. Conclusions These findings suggest that management strategies and conservation practices must integrate proper actions that consider both local and regional scales. For existing fragmented landscapes, it is important to increase forest availability at the regional scale, while also maintaining high environmental heterogeneity at the local scale. We believe that with proper landscape planning this multiscalar approach can be not only more effective, but also easier to implement.Electronic supplementary material The online version of this article (
Agriculture driven landscape changes has caused worldwide forest loss and fragmentation, seriously affecting biodiversity and ecosystem services, amongst which pollination is remarkably important. Bees are an essential pollinator group for forest plant populations and food production in tropical landscapes. They are also dependent on forested environments which are essential to maintain their diversity and pollination services. We analyzed bee diversity in contrasting forest and adjacent non-forest patches to evaluate if bees can use complementary non-native environments in heterogeneous altered tropical landscapes. The effect of landscape level heterogeneity and forest amount on bee diversity was also assessed. Our hypothesis was that bee communities would be more rich and diverse inside the forest understory, but due to supplementary foraging behaviors they would be more abundant in non-forested areas where flower availability is higher. We actively sampled bees visiting flowers within forest patches and in surrounding non-forest open areas between the Cantareira and Mantiqueira mountain ranges in São Paulo, Brazil. We found higher bee richness and diversity in open areas than in forest patches, partially denying our initial hypothesis but supporting that bees are more abundant in non-forest areas. We found strong indication that landscapes with higher amount of forest and environmental heterogeneity can provide more resources for bees through resource complementation processes, maintaining their diversity in the landscape. The presence of forest patches close to crop and open areas is of utmost importance for the conservation of bees and pollination services with important consequences for land management in tropical environments.
Objective: To accomplish a systematic review of literature with overall survival meta-analysis about the role of microRNA in epithelial ovarian cancer as prognostic and predictive factor to chemotherapy response. Methods: A search was conducted in the PubMed database, using the keywords "microRNA" and "ovarian cancer" or "miRNA" and "ovarian cancer". Original articles published before 02/02/2019 that had as main subject microRNA (miRNA) and ovarian cancer were included. We considered for inclusion only studies that associated microRNA to chemotherapy-related diagnosis, prognosis, or response in ovarian cancer. Results: The literature search returned 1,482 articles, 497 of which fulfilled inclusion criteria, yielding 350 miRNAs. The status of each miRNA was assessed in serum and tissue of ovarian cancer, benign tumors, and healthy tissue. The status of up-/downregulation of miRNAs was related to prognostic features (overall survival and disease-free survival) and response predictive features such as platinum and paclitaxel sensitivity/resistance. The miRNAs that had been cited three or more times were selected for prognostic and response predictive features analysis. Twelve miRNAs fulfilled all these criteria and were included in the overall survival metaanalysis. Conclusions: miRNAs affect virtually all mechanisms of carcinogenesis, working as either oncogenes or tumor suppressor genes. In this systematic review we identified miRNAs that may be related to prognosis, diagnosis, and chemotherapy sensitivity. The 12 miRNAs identified here should be included in future studies for validation.
Mutualistic interactions between plants and pollinators play an essential role in the organization and persistence of biodiversity. The structure of interaction networks mediates the resilience of local communities and ecosystem functioning to environmental changes. Hence, network structure conservation may be more critical for maintaining biodiversity and ecological services than the preservation of isolated species in changing landscapes. Here, we intensively surveyed seven 36 km 2 landscapes to empirically investigate the effects of forest loss and landscape configuration on the structure of plantpollinator networks in understory vegetation of Brazilian Atlantic Forest. Our results indicate that forest loss and isolation affect the structure of the plant-pollinator networks, which were smaller in deforested landscapes, and less specialized as patch isolation increased. Lower nestedness and degree of specialization (Hʹ 2 ) indicated that the remaining plant and bee species tend to be generalists, and many of the expected specialized interactions in the network were already lost. Because generalist species generate a cohesive interaction core in these networks, these simplified networks might be resistant to loss of peripheral species, but may be susceptible to the extinction of the most generalist species. We suggest that such a network pattern is an outcome of landscapes with a few remaining isolated patches of natural habitat. Our results add a new perspective to studies of plant-pollinator networks in fragmented landscapes, showing that those interaction networks might also be used to indicate how changes in natural habitat affect biodiversity and biotic interactions.
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