Biology subjects

Igea, J.

Publications and source records attributed to Igea, J..

3 recordsLinked to original sources

bioRxiv2018

Different macroevolutionary routes to becoming a biodiversity hotspot

Why is species diversity so unevenly distributed across different regions on Earth? Regional differences in biodiversity may stem from differences in rates of speciation and dispersal and colonization times, but these hypotheses have rarely been tested simultaneously at a global scale. Here we uncovered the routes that generated hotpots of mammal and bird biodiversity by analyzing the tempo and mode of diversification and dispersal within major biogeographic realms. Hotspots in tropical realms had higher rates of speciation whereas those in temperate realms received more immigrant species from their surrounding regions. We also found that hotspots had higher spatial complexity and energy availability, providing a link between the environment and macroevolutionary history. Our study highlights how assessing differences in macroevolutionary history can help to explain why biodiversity varies so much worldwide.

evolutionary biology↗

bioRxiv2018

Trait evolution and historical biogeography shape assemblages of annual killifish

Reconstructions of evolutionary and historical biogeographic processes can improve our understanding of how species ssemblages developed and permit inference of ecological drivers affecting coexistence. We explore this approach in Austrolebias, a genus of annual fishes possessing a wide range of body sizes. Regional assemblages composed of different species with similar size distributions are found in four areas of eastern South America. Using phylogenetic trees, species distribution models and size data we show how trait evolution and historical biogeography have affected the composition of species assemblages. We extend age-range correlations to improve estimates of local historical biogeography. We find that size variation principally arose in a single area and infer that ecological interactions drove size divergence. This large-size lineage spread to two other areas. One of these assemblages was likely shaped by adaptation to a new environment, but this was not associated with additional size divergence. We found only weak evidence that environmental filtering has been important in the construction of the remaining assemblage with the smallest range of sizes. The repeated assemblage structures were the result of different evolutionary and historical processes. Our approach sheds light on how species assemblages were built when typical clustering approaches may fall short.

evolutionary biology↗

bioRxiv2017

Evolutionarily younger and faster diversifying plants are more threatened by extinction

Extinction threatens many species, yet few factors predict this risk across the plant Tree of Life (ToL). Taxon age is one factor that may associate with extinction if occupancy of geographic and adaptive zones varies with time, but evidence for such an association has been equivocal. Age-dependent occupancy can also influence diversification rates and thus extinction risk where new taxa have small range and population sizes. Here we analysed 509 well-sampled genera from across the plant ToL. We found that a greater proportion of species were threatened by extinction in younger and faster-diversifying genera. Repeating our analyses in two large, well-sampled groups, we found that extinction risk increased with evolutionary age in conifer species but not palms. Potential range size decreased in older, non-threatened conifers more strongly than in threatened taxa, suggesting that range size dynamics may explain differing patterns of extinction risk across the ToL with consequences for biodiversity conservation.

evolutionary biology↗