Influence of Productivity and Disturbance on Plant Species Diversity Across the Grasslands of the Great Plains
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Plant species diversity is a critical element for the stability and functionality of all types of ecosystems. The drivers of plant species diversity remain up for debate with varying views of how a high level is achieved and maintained across all ecosystems. Literature states that intermediate levels of productivity and disturbance are essential for these high levels to be present. This logic has been disputed through empirical tests; however, other claims hold that these intermediate levels have not been appropriately examined. Here, I investigate the influence of productivity and disturbance (i.e., fire) on plant species diversity. I set up experimental plots across the grassland prairies of Kansas where diversity, productivity, and fire patterns vary considerably. I conducted this study in the wetter, tallgrass prairies of eastern Kansas at Konza Prairie Biological Station and in the drier, mid- to short-grass prairies of western Kansas at Smoky Valley Ranch. Based on these locations, I positioned plots under different fire frequencies across moisture gradients topographically and regionally. I assessed productivity by clipping standing vegetation, drying it, and then weighing it. I controlled for the fire variable by examining areas under prescribed burn treatments based on time since most recently burned. I found that plant species diversity does not significantly differ across topography in tallgrass prairies though it did differ significantly across the climatic regional gradient of Kansas. From my results, I have concluded that productivity and disturbance influence plant species diversity of the Great Plains though other variables likely drive plant species diversity as well such as annual versus perennial dominance, season of burn, and grazing.
Intermediate Productivity Hypothesis
Intermediate Disturbance Hypothesis
Dynamic Equilibrium Model
McConaghy, Scott Carlton (2016). Influence of Productivity and Disturbance on Plant Species Diversity Across the Grasslands of the Great Plains. Master's thesis, Texas A & M University. Available electronically from