This project addresses a critical question at the intersection of ecology and evolution: what ecological factors maintain genetic variation within a keystone species in an ecosystem and how does that genetic variation feedback on food web interactions to influence temporal variation in the structure and function of ecosystems? This project further extends that question to a metacommunity perspective by explicitly considering spatial variation in ecological communities across a landscape. The research focuses on Daphnia pulex, which is a common grazer species of zooplankton in freshwater ponds. Daphnia reproduce by facultative parthenogenesis and populations are composed of different clones known to vary in ecological traits. Molecular genetic approaches will be used to quantify spatial and temporal clonal variation within and among different pond populations. Hypotheses concerning the relationship of this clonal variation to ecological function will be tested in manipulative experiments conducted in field mesocosms. One trait that is hypothesized to vary among clones is their thermal tolerance; experiments will test for the significance of this variation in enabling populations to adapt to climate warming. This research is ambitious and risky, but also has high potential to produce results that could be transformative to the science of ecology. This project is being funded as an EAGER: Early concept Grant for Exploratory Research.
This project will provide research training in aquatic evolutionary ecology for undergraduate and graduate students, including individuals from underrepresented groups. The results from this project will aid in understanding how climate warming will impact aquatic habitats and the relationship between biodiversity and ecosystem processes. The project provides support to a beginning investigator at an early career stage.
As anthropogenic threats continue to impact the diversity of natural systems it has become imperative to identify the mechanisms that maintain patterns of diversity and to understand how alterations in diversity can impact population and community stability. Central to this issue is the maintenance of genetic and phenotypic variation within and among populations of species. This question has long received attention from evolutionary biologists, and an important recurring theme from this work is the role of biotic interactions such as exploitative resource competition. While these forces are widely recognized as potentially important drivers of population-level variation, much less understood is how their action and importance varies with spatiotemporal variation in abiotic conditions and dispersal among populations. This grant focused on the effects of environmental variation on the genetic diversity and stability of Daphnia pulex (a vital species of zooplankton important for the integrity and health of natural ponds and lakes). Experiments showed that dispersal of individuals among ecosystems can play an important role in the prolonged persistence and stability of populations that experience short-term environmental fluctuations in pH and nutrient variability. This grant supported one female graduate student and one female, minority student as a summer REU participant. Three undergraduates have participated as paid research assistants (one female, one minority), one of which is a co-author on one publication (Steiner et al. 2011). I have also involved several undergraduates in this project who have received course credits for participating (11 students total, five of which were female).
