IMPACT OF LANDSCAPE DISTURBANCE AND HABITAT FRAGMENTATION ON THE EVOLUTIONARY TRAJECTORIES OF PLANT SPECIES
Anthropogenic habitat disturbance has become nearly ubiquitous, often resulting in a mosaic of habitat patches within a matrix of disturbance. Fragmentation of once continuous habitat can have multiple consequences for species occupying surviving patches, including loss of rare alleles, increased inbreeding, and reduced rates of gene flow. Our lab investigates levels and spatial partitioning of genetic variation in natural plant populations to develop insights into how well genes are exchanged between populations and whether species are effectively maintaining species wide levels of genetic variation. Of particular interest is the relative importance of pollen mediated gene flow versus seed mediated gene movement among populations, one or both of which often require animal vectors. While we work on a variety of plant taxa, we have had a particular focus on Neotropical orchids and epiphytes.
COLONIZATION, LONG DISTANCE SEED DISPERSAL AND POTENTIAL RANGE EXPANSION, PARTICULARLY IN THE CONTEXT OF CLIMATE CHANGE
Colonization is a fundamental ecological process that affects the ability of all species to persist and undergo range shifts and/or expansion in continually shifting landscapes. Understanding the mechanisms that affect colonization is therefore of critical importance at a time of widespread habitat degradation and rapid climate change. The role of rare long distance seed dispersal events in colonization is of particular interest in the context of a rapidly changing climate, as the current rate of change will challenge the ability of sedentary species to modify their ranges to climatic zones within their physiological limits.
Our lab is interested in using phylogeographic analyses for the purpose of identifying ancient refugia associated with Pleistocene glacial maxima and subsequent expansion zones of plant taxa in response to a warming climate. Refugia during the last glacial maximum often leave a genetic footprint and by comparing the locations and genetic composition of refugial populations with the current range and genetic makeup of species, insights can be gained regarding the dispersal and colonization ability of focal taxa.