Browsing by Subject "local adaptation"

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Adaptations Between Ecotypes And Along Environmental Gradients In Panicum Virgatum*
(2014-05) Lowry, David B.; Behrman, Kathrine D.; Grabowski, Paul; Morris, Geoffrey P.; Kiniry, James R.; Juenger, Thomas E.; Lowry, David B.; Juenger, Thomas E.
Determining the patterns and mechanisms of natural selection in the wild is of fundamental importance to understanding the differentiation of populations and the evolution of new species. However, it is often unknown the extent to which adaptive genetic variation is distributed among ecotypes between distinct habitats versus along large-scale geographic environmental gradients, such as those that track latitude. Classic studies of selection in the wild in switchgrass, Panicum virgatum, tested for adaptation at both of these levels of natural variation. Here we review what these field experiments and modern agronomic field trials have taught us about natural variation and selection at both the ecotype and environmental gradient levels in P. virgatum. With recent genome sequencing efforts in P. virgatum, it is poised to become an excellent system for understanding the adaptation of grassland species across the eastern half of North America. The identification of genetic loci involved in different types of adaptations will help to understand the evolutionary mechanisms of diversification within P. virgatum and provide useful information for the breeding of high-yielding cultivars for different ecoregions.
Evolution In Metacommunities: On The Relative Importance Of Species Sorting And Monopolization In Structuring Communities
(2008-06) Loeuille, Nicolas; Leibold, Mathew A.; Loeuille, Nicolas; Leibold, Mathew A.
Adaptive evolution within species and community assembly involving multiple species are both affected by dispersal and spatiotemporal environmental variation and may thus interact with each other. We examined this interaction in a simple three-patch metacommunity and found that these two processes produce very different associations between species composition and local environment. In most conditions, we find a pattern we call >species sorting,> wherein local adaptation by resident species cannot prevent invasions by other preadapted species as environmental conditions change (strong association between local environmental conditions and local community composition). When dispersal rates are very low relative to the other two rates, local adaptation by resident species predominates, leading to strong priority effects that prevent successful colonization by other species that would have been well adapted, a pattern we call > local monopolization.> When dispersal and evolutionary rates are both very high, we find that an evolving species outcompetes other species in all patches, a pattern we call > global monopolization.> When environmental oscillations are very frequent, local monopolization predominates. Our findings indicate that there can be strong modification of community assembly by local adaptive processes and that these depend strongly on the relative rates of evolution, dispersal, and environmental change.