Abstracts (first author)


Incorporating intraspecific variation in conservation prioritization: a multi-taxa approach

Author(s): Thomassen HA, Fuller T, Buermann W, Mila B, Kieswetter CM, Jarrin-V. P, Modro N, Cameron SE, Mason E, Schweizer R, Schlunegger J, Chan J, Wang O, Peralvo M, Schneider CJ, Graham CH, Pollinger JP, Saatchi S, Wayne RK, Smith TB


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)

Author(s): Thomassen HA, Waider C, Dekker RWRJ, Smith TB


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.

Abstracts (coauthor)


To determine the plausibility of sympatric speciation, we need to determine its relative rate of occurrence across different speciation events. Here we focus on a small taxonomic group and a particular speciation mechanism which requires sympatry: the emergence of a large and small species pair where the large cannibalizes the small. This scenario has been named “giant-dwarf” diversification. A comparative analysis of body size measures of Austrolebias South-American annual killifish suggests that species evolve towards one of three size optima. Species evolving towards the largest optimal size appeared at least three times from small in the Austrolebias genus. The first large ancestral species per event appeared in a trait change with relatively high speed in all three cases, consistent with expectations of cannibalism evolution. A comparative analysis of lower jaw length, a proxy for the level of specialization in piscivory suggests that in one clade of large species trait values indicate a very weak or no specialization towards piscivory, and that in the two other clades species are selected towards two optima with relatively large jaw lengths. By means of a reconstruction of ancestral species ranges we show that speciation events leading to a large and smaller species pair were sympatric with a large likelihood. For the clade of large species with little specialization, the probability that speciation was non-sympatric is largest among the three events. Conditional on the data we analysed, one can therefore conclude that giant-dwarf speciation by cannibalism most probably occurred twice in Austrolebias and that a third appearance of large species in the genus likely occurred by other selective or non-selective processes.


Chairman: Octávio S. Paulo
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XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon


Computational Biology & Population Genomics Group