RESUMO

Women underrepresentation in science has frequently been associated with women being less productive than men (i.e. the gender productivity gap), which may be explained by women having lower success rates, producing science of lower impact and/or suffering gender bias. By performing global meta-analyses, we show that there is a gender productivity gap mostly supported by a larger scientific production ascribed to men. However, women and men show similar success rates when the researchers' work is directly evaluated (i.e. publishing articles). Men's success rate is higher only in productivity proxies involving peer recognition (e.g. evaluation committees, academic positions). Men's articles showed a tendency to have higher global impact but only if studies include self-citations. We detected gender bias against women in research fields where women are underrepresented (i.e. those different from Psychology). Historical numerical unbalance, socio-psychological aspects and cultural factors may influence differences in success rate, science impact and gender bias. Thus, the maintenance of a women-unfriendly academic and non-academic environment may perpetuate the gender productivity gap. New policies to build a more egalitarian and heterogeneous scientific community and society are needed to close the gender gap in science.

RESUMO

Waterbirds have a major functional role in wetlands, and understanding how functional traits of waterbirds depend on environmental characteristics can facilitate management of ecosystems and their services. We investigate how the waterbird community in a Neotropical river-floodplain system responds to environmental gradients, identifying how they affect waterbird species richness, functional diversity (measured as functional dispersion) and functional composition (specific functional traits). We sampled 22 lakes in the Upper Paraná floodplain system in southern Brazil, and modelled avian functional diversity and species richness as a function of environmental variables. Then we used a unified RLQ and fourth-corner analysis to evaluate environment-trait relationships. Waterbird species richness and functional diversity varied according to different environmental variables. Lake area and diversity of aquatic vegetation were associated with avian species richness, while relative abundance of grass and emergent macrophytes and mean and variation of depth were related to functional diversity. Furthermore, changes in functional diversity seemed to be mainly driven by presence of species that depend on perches for foraging (e.g. kingfishers, cormorants, and kites), whose presence was mainly associated with deep water and emergent macrophytes. Nevertheless, changes in functional diversity and functional composition did not depend on exactly the same set of environmental variables, suggesting that trait combinations (e.g. below surface feeders who feed on fish), not only specific traits, are important drivers of the variation in functional diversity between lakes. Given the observed differences in responses of species richness and functional diversity, both these diversity metrics should be used as complementary tools in ecosystem management. Furthermore, our results show that functional diversity and composition are partially coupled, suggesting that although functional diversity is influenced by the environmental filtering of particular traits, it also reflects other ecological mechanisms (e.g. competitive interactions among species).

Assuntos

RESUMO

The mutualistic interaction between frugivore birds and the fruiting plants they disperse presents an asymmetric interaction pattern, with some species having a more important role (i.e. being essential) for maintaining the structure and functioning of the interaction network. The identification of the biological characteristics of these species is of major importance for the understanding and conservation of seed-dispersal interactions. In this study, I use a network approach and avian seed-dispersal networks from 23 different geographical areas to test five hypotheses about species characteristics determining the structure of the assemblage. I expected (i) large birds to forage on a large number of fruits and (ii) large fruits to be dispersed by few bird species (because of morphological constraints), and (iii) highly energetic fruits to be dispersed by more bird species (in accordance with optimal foraging theory). Besides the number of interacting partners, I also expected (iv) large birds and (v) small energetic fruits to be important for the maintenance of the structure of the interactions in seed-dispersal networks. As species that are closely related are more likely to be similar to each other, I performed phylogenetically corrected analyses to account for this data dependence. Although bird size was not associated to species important in the maintenance of the structure of the seed-dispersal community, I identified that bird species whose diet was strongly dependent on fruits were important for the structure of the network. Regarding the plants, I found that large fruits were dispersed by fewer species, but the most important attribute to predict the role of a fruit was its energy content (higher energy, more bird species dispersing the plant, but low-energy fruits being of conservation concern because they are dispersed by specific species). The results of this study suggest that the role of the species in seed-dispersal assemblages seems to be determined by the role of the species as consumers (frugivory degree for animals) or by their nutritional inputs (energy content for fruits) rather than by morphological constrains.

Assuntos