Plant community changes on restored grasslands across a largescale environmental gradient
Abstract
Identifying the factors that structure communities across an environmental gradient is a
commonly studied and often debated topic in plant community ecology. Despite substantial
attention, a consensus has not been reached regarding which factors are the most important or
how communities respond. This is especially true for grasslands, where habitat loss has limited
opportunities for systematic study across key environmental gradients. Here we overcome these
limitations by examining CRP restored plant community responses to a large-scale
environmental gradient and to two, common management approaches. We acquired 55 CRP
sites across the state of Kansas representing short, mixed, and tallgrass prairie that were restored
and managed using either CP2 or CP25 management strategies. The longitudinal environmental
gradient was composed of changes in mean annual precipitation, temperature, elevation, soils,
and disturbance regimes. Plant community and soil data were collected in the spring and
summer of 2017. Mean annual precipitation was the most important predicator of species
richness which had a positive, linear response across the gradient. To a lesser degree,
management practices also played a role in determining community structure. The linear
increase in richness that we observed across the precipitation gradient reflects the increase in
species pool size from short to tallgrass plant communities and explained most of the richness
variation despite large changes in plant communities. This linear richness response contrasts
with unimodal responses to gradients reported elsewhere, highlighting uncertainties at the high
end of resource gradients. These findings provide insight into the diversity constraints and
fundamental drivers of change across a large-scale gradient representing a wide variety of
habitats and conditions in grassland systems.
Description
Thesis (M.S.)-- Wichita State University, College of Liberal Arts and Sciences, Dept. of Biological Sciences