Woody plant invasion into grasslands in the Konza Prairie Long-term Ecological Research site
Space grant funds were used to support the research activities of PhD student, Duncan McKinley in the Division of Biology at KSU. Duncan's work examines the ecosystem and biogeochemical consequences of ongoing changes in land-cover in the grasslands of the Central US. Woody plant invasion into grasslands is an important aspect of global change, and has been documented, as of yet little is known regarding the ecosystem-level consequences of this land cover change. This research focuses on areas that have undergone recent (last 40-60 years) shifts from tallgrass prairie plant communities to woodlands dominated by eastern red cedar (Juniperus virginiana). This is an integral part of a larger NASA-funded Land Cover/Land Use Change (LCLUC) project to (1) use remotely sensed data to determine rates and patterns of woody encroachment over space and time in the Great Plains, (2) assess the ecosystem and biogeochemical consequences of this change in land cover, and (3) develop a predictive model to forecast future rates of woody encroachment. Our approach is strongly multi-disciplinary, and involves in situ ecosystem and biogeochemical studies at the plot-level, linked with multi-temporal Landsat images and historical aerial photos, and development of predictive biogeochemical models. Duncan's research includes state-of-the-art stable isotope approaches combined with field-based assessment of soil N transformation rates to determine how tree invasion into grasslands alters the cycling and availability of nitrogen, and important limiting nutrient in these ecosystems. This research addresses some potentially important changes in ecosystem funtcion associated with land-cover change, and will also contribute to the parameterization of our biogeochemical model.