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Because gene flow plays a key role in evolutionary processes, quantitative analyses of gene flow have been conducted for half a century (Dobzhansky and Wright 1943; Wright 1946) and are [...]

Summary: Ironstone outcrop habitats harbour rare and endemic rupicolous plants. In southeast Brazil, they concentrate on mountaintops in the Iron Quadrangle (IQ), an intensively exploited iron ore reserve. To evaluate the current habitat availability of 32 plants endemic to canga (ironstone outcrops) and to support priority conservation areas and actions, we compared their functional connectivity in the IQ before (1960s) and after (2014) massive habitat loss to opencast mining. The Integral Index of Connectivity and associated metrics of habitat availability were used to evaluate present and past connectivity at a threshold distance of 500 m. The overall canga habitat loss up to 2014 was 50%. The historical configuration of 334 patches totalling 18 654 ha was already disconnected and the proportion of patches acting as relevant stepping stones was thus very low. Furthermore, in both the historical and current settings, the largest contribution to habitat availability came from 'intrapatch connectivity' (i.e., patch area), especially in the east sector. All the IQ canga endemics fall into the International Union for Conservation of Nature (IUCN) Critically Endangered category and require protection. The recommended strategy for their conservation is to protect large, preferably well-preserved ironstone patches. This measure will require finding the middle ground between economic development and conservation of natural heritage. [ABSTRACT FROM AUTHOR]

Seed dispersal effectiveness (SDE) is a useful framework to explore the evolutionary and ecological consequences of seed dispersal to plant fitness. However, SDE is poorly studied in tropical open grasslands. Here, we studied both quantitative and qualitative components of SDE in two species of Miconia (Melastomataceae) from ferruginous campo rupestre, a vegetation highly threatened by mining activities. We determined fruit traits and fruit availability and found that fruits of both species are produced in times of resource scarcity at the study site. Based on the number of visits and the number of fruits removed per visit, we calculated the quantitative component of SDE for both species. Finally, we explored the qualitative component of SDE by means of a controlled experiment that simulated the effects of gut passage on seed germination. Bird species differed strongly in the quantitative component of SDE. Gut passage did not affect germination compared with hand-extracted seeds, except for a minor negative effect on germination time in M. pepericarpa. However, seeds within intact fruits showed lower germination percentages compared with hand-extracted seeds. Our data indicate that Miconia species from ferruginous campo rupestre are visited by a diverse assemblage of generalist birds that differ in quantitative, but not qualitative, seed dispersal effectiveness. We argue that planting Miconia species can overcome seed limitation in degraded areas and thus assist ecological restoration after mining abandonment. [ABSTRACT FROM AUTHOR]

Vriesea minarum is a bromeliad endemic to the Iron Quadrangle region in Minas Gerais state, Brazil and is currently listed as an endangered species. The aim of our study was to investigate the species floral biology, breeding system, and post-seminal development. Observations and experiments were conducted in the Rola-Moça State Park. Flowers have morphological characteristics typical for the genus but we discuss the position of the ovary, oversimplified in some papers as superior. Seed set indicates that V. minarum is predominantly outcrossing, but self-compatible as well. The floral biology indicates flower protandry, and suggests a mixed pollination syndrome, as was observed recently in other bromeliads. Due to the survival risk facing this species, we suggest that more studies investigating the potential to preserve germplasm should be conducted, since its seeds appear to have a limited viability. [ABSTRACT FROM AUTHOR]

The floral biology of the sand dune shrubEriope blanchetii(Benth) Harley was investigated in a wild population located within an environment protection area near Salvador, NE Brazil. Inflorescence and flower development were monitored, and the reproductive biology was assessed. Inflorescences are terminal panicles, each bearing from one to 38 small, zygomorphic flowers. The duration of an inflorescence is about 2 months, with few new flowers each day. The rewards to visitors are pollen and nectar, the latter being produced in small quantities at the corolla base, near the stylopodium. Three sequential phases of flower development were identified, based on colour changes, pollen and nectar availability, and stigmatic receptivity. Anthesis takes place throughout the day within each plant, and flowers are strongly protandrous. Flowers are short-lived, with individual variations of 7–30 h until corolla abscission. This variation is probably associated to a post-pollinating response, which reduces the length of the female phase and could be advantageous for the economy of nectar production and for increased efficient pollination of the remaining flowers on a plant. The results of the pollination tests (apomixis, spontaneous and manual autogamy, manual cross-pollination, and control) reinforced the role of pollinators for the reproductive success ofE. blanchetii, given that the production of fruits from spontaneous pollination is unlikely to be resulting from protandry and given the morphological floral features. Taken together, the morphological and physiological aspects ofE. blanchetiifloral biology favour cross-pollination, and it is likely that most of the fruits in nature are produced by outcrossing. [ABSTRACT FROM AUTHOR]

Cave entrances are transition zones with intermediate characteristics between epigean environments, which bear lower environmental stability, and hypogean environments, with lower food resources. Associated to these interfaces there is a specific community, capable of exploiting its unique and intermediate characteristics. This work investigated this community in a Brazilian limestone cave, identifying its arthropod species composition and spatial distribution, and exploring its relationships with climatic and structural environment characteristics and trophic relations. An ecotone zone was identified, with 55 species found only in the ecotone, 49 species were shared with the epigean community, 37 species with the hypogean community, and 14 species were found in the three communities. Although detritus is the base of the trophic web in the entrance, light allows the establishment of some producers and even herbivores. Species diversity in the ecotone was intermediate to that of the adjacent environments. Light is the main filter that acts near the cave entrance and determines the presence and distribution of several species in the ecotone. Therefore, this region is important for the cave ecosystem as a whole, considering that a considerable amount of trophic resources is transferred from the epigean to the hypogean environment through this area. Accordingly, conservation and management strategies regarding cave communities should incorporate actions to study and protect ecotonal communities. [ABSTRACT FROM AUTHOR]

An analysis of the foraging behavior of the bee Xylocopa (Neoxylocopa) cearensis Ducke among shrubs of Cuphea brachiata Koehne (Lythraceae), a key component in the Abaeté coastal sand dunes, Salvador, BA, Brazil, suggests that this bee is very important for the maintenance of the plant population, performing the pollination. This dispersal, however, is spatially restricted, so the populations in the area are likely to be highly structured genetically.