Abstracts (first author)
Incorporating intraspecific variation in conservation prioritization: a multi-taxa approach
Human-induced land use changes are causing rapid habitat fragmentation. Species are therefore exceedingly limited in shifting their ranges in response to climate change, and likely need to adapt in situ to changing climate conditions. A prudent strategy to maintain the ability of populations to adapt is to focus conservation efforts on areas where levels of standing intraspecific variation are high. By doing so, the potential for an evolutionary response to environmental change is maximized. We used spatially explicit ecological modeling approaches in conjunction with environmental variables to model species distributions and patterns of genetic and morphological variation in seven Ecuadorian amphibian, bird, and mammal species. We then used reserve selection software to prioritize areas for conservation based on evolutionary process (intraspecific genetic and morphological variation) or biodiversity patterns (species-level diversity). Reserves selected using species-level data showed little overlap with those based on genetic and morphological variation. Priority areas for intraspecific variation were mainly located along the slopes of the Andes, and were largely concordant among species, but were not well represented in existing reserves. Our results imply that in order to maximize representation of intraspecific variation in reserves, genetic and morphological variation should be included in conservation prioritization. To test the general applicability of our conservation prioritization framework, we are now applying this approach to target areas with varying levels of disturbance, different environmental gradients, and at small to large scales across four continents. Preliminary analyses indicate that the approach may be particularly useful at large scales, whereas other approaches should inform small-scale prioritization efforts.
A potential role for ecologically mediated sexual selection in the divergence of Tropical Pacific honeyeaters (Myzomela)
The relative roles of neutral and selective processes in divergence are of key interest in evolutionary biology. Due to the many large and small islands, the Indopacific area constitutes an ideal natural laboratory to study the different modes of diversification. It is a biotically extremely rich region, and as a result is designated as several distinct biodiversity hotspots. It was suggested that the islands of the Pacific are a likely source of biodiversity, rather than a sink of species that originated on the mainland, as has long been the established hypothesis. We use landscape genetic approaches to study the potential roles of drift, natural selection, and sexual selection to study the divergence among island and mainland species of sexually dimorphic honeyeaters, Myzomela sp. Sequence and microsatellite data indicate that these populations either very recently diverged or experience ongoing gene flow, and planned coalescence-based analyses will be useful in distinguishing these two hypotheses. We found that males exhibit distinct differences between islands in plumage coloration and song, but not in other, fitness-related morphological traits. Females did not show divergence in any morphological traits between islands. Environmental heterogeneity explained the observed divergence in song frequency characteristics, whereas oceanic barriers better explained divergence in temporal traits. These results suggest that sexual selection is a potential factor in maintaining and deepening population differentiation, and that environmental conditions pose selection pressures on some but not all sexual traits. The role of sexual selection in population divergence will be further evaluated using mate choice experiments.