The Causes and Consequences of Phenotypic Variation in Plants
Plants are particularly interesting study organisms because they are sessile and must match their phenotype and phenology to the local environment. The time frame for evolutionary change in plants can be quite rapid, and considering the pace of human-mediated changes to land use and climate, understanding evolution over a shorter “ecological” time frame is very relevant. Furthermore, in plants, the connection between habitat and phenotype is pronounced, and so the potential for adaptation (local and broad-scale) is wide-ranging.
We have been studying natural variation in plant phenotypes, such as flowering time, tolerance to apical meristem damage, and root morphology, with the goal of understanding the networks of genes that influence the patterns of phenotypic variation in the wild. We have identified polymorphic genes associated with phenotypic variation, and confirmed associations using knockout mutants and other approaches. We have also followed up by investigating the ecological context of several of these genes and the phenotypes associated with them, making connections to macroecological properties of species using the genetic information.
Integrative Conservation Biology: Understanding Diversity at Different Levels
Integrative biology is the study of the living world that combines two or more different scales of analysis (genes and biochemical mechanisms, individuals, populations, species, communities, landscapes, and/or ecosystems) simultaneously in order to answer important biological questions. The idea is that constraints imposed by one level of study percolate up or filter down to other levels of study, and therefore one must understand the phenomena occurring at other levels of analysis to understand the phenomena at the focal level. For instance, if genetic pathways for two different traits are physiologically interrelated (perhaps because they share common metabolic intermediates), then this will cause those traits to covary in ways that may not be “breakable” by opposing selection gradients on the two traits; or if two populations of a species are separated by physical barriers on the landscape, then they will not exchange alleles to the extent predicted by non-spatially explicit population genetic models.
The nuance provided by an integrative approach is necessary to model species dynamics appropriately. This becomes particularly important when studying taxa of conservation concern, whether invasive taxa or rare/threatened/endangered taxa. For instance, to model the susceptibility of a region to an invasive species, an understanding of the conditions allowing for the spread of an the species must be paired with an understanding of where these conditions occur on the landscape; or to model the effect of a particular management strategy (or perhaps no management at all) for the preservation of an endangered species, one must understand how that strategy affects the species’ metabolism and the downstream (perhaps physiologically interrelated) consequences for multiple traits.