Research

The ability of a plant species to move its seeds across space determines its rate of invasion or range expansion, geographic range size, and ability to withstand climate change and habitat fragmentation. For seed dispersal to be successful, individuals must survive and reproduce in the post-dispersal environment. Both the quantity and genetic/phenotypic composition of dispersed individuals contribute to post-dispersal population success.

In a field-greenhouse study, I set-up seed capture trays at 2 distances (Close and Far, see figure to the left) from GrENE-net source trays consisting of ~200 native ecotypes of Arabidopsis thaliana in a field site in North Carolina. The seed capture trays were brought into the greenhouse after the natural seed dispersal season and given optimal growth conditions. I counted the number of plants that emerged, measured various individual traits, and pool-sequenced leaf tissue in trays from both distances.

Check back here soon for results!

Continuous seed dispersal among populations can affect population size, the distribution of phenotypic and genetic variation within and between populations, and density-dependence. Dispersal can supplement population sizes and increase the genetic variation within populations, both of which can increase the probability of population persistence.

In an add-on to GrENE-net, I set-up population trays that were either open to dispersal (no cages) or closed to dispersal (open-top cages). These populations with high starting genetic variation were allowed to naturally cycle for 3 years. Throughout the experiment, I collected floral tissue for pool-sequencing and measured population size, size at reproduction, reproductive output, and various reproductive traits.

Check back here soon for results!

Phenological tracking has been shown to be important for species persistence in response to climate change. Phenological tracking via germination time regulation may be especially impactful since germination time determines the environmental conditions that a plant will experience throughout the life cycle.

I established 112 genetically variable experimental populations of A. thaliana with about 620 seeds from one of three recombinant inbred line sets (RIL sets) that differed at 2-3 major dormancy loci. I imposed environmental manipulations of soil composition, temperature, and moisture conditions. 48 “Mixed” populations were composed of both dormant and non-dormant genetic lines to investigate the evolution of dormancy itself during the experiment. I monitored environmental conditions, germination timing, population size, population persistence, and measured various individual traits.

Check back here soon for results!

Since both spatial and temporal dispersal are expected to be key to population persistence in response to climate change, it is important to understand their combined and relative effects.

Combining data from both my spatial dispersal and seed dormancy experiments, I will use a population viability model to test for the joint long-term metapopulation effects of spatial and temporal dispersal.

Check back here soon for more details and results!