​​​PALMQUIST LAB

Plant Ecology at Marshall University​

Big sagebrush plant biodiversity patterns across space

A key challenge in ecology is to identify which community assembly processes influence biodiversity patterns across multiple scales. Despite the importance of sagebrush shrublands in the western US, very little work has focused on quantifying plant biodiversity patterns in the herbaceous layer. We address this knowledge gap by exploring the geographic patterns of plant biodiversity and examining how soil water availability, along with livestock grazing, influences multiple dimensions of plant biodiversity.

RESEARCH

Using functional and phylogenetic diversity to understand community assembly along gradients


The merging of community ecology and evolution have provided new theoretical insights and methodological approaches for inference of community assembly processes. Our work in this arena uses functional diversity of traits hypothesized to respond to competition and environmental filtering, respectively in combination with phylogenetic diversity to infer shifts in the relative importance of competition and environmental filtering along stress gradients.
Our research focuses on quantifying vegetation dynamics over space and time and identifying how the relative importance of ecological processes structuring plant communities changes with spatial and temporal scale. In addition, a key goal of our research is to understand how pattern and process in plant communities will be altered in the face of global environmental change. An important motivation is to understand ecological patterns and processes at large spatial scales to inform landscape conservation. We collect field data, use existing large observational data sets, and implement  simulation modeling to answer these questions in temperate shrublands, woodlands, and forests.
Modeling big sagebrush ecohydrology and plant comunities in response to changing climate, fire and livestock grazing


Climate change is predicted to increase the severity and number of drought events in parts of western North America, while soil water availability may increase in other portions of the landscape. Our current research uses two coupled simulation models to explore the impacts of climate change, livestock grazing, and fire on ecohydrology and big sagebrush community composition and biomass across the range of the big sagebrush distribution to guide landscape conservation and prioritization.

Community assembly in longleaf pine plant communities


Community assembly is the process in which species are filtered into ecological communities. Multiple processes, which often operate at different spatial and temporal scales, are thought to act synergistically to influence the number and identity of species in local communities. Thus, a key challenge in ecology is to identify those processes and determine their relative importance. In this body of research, we explore vegetation patterns in the longleaf pine ecosystem and quantify the relative importance of multiple ecological processes (fire, soil properties, climate, biogeography history, competition, stochasticity) structuring those patterns over both space and time.