Sally Koerner receives NSF Doctoral Dissertation Improvement Award!

Sally Koerner recently learned that her NSF Doctoral Dissertation Improvement Grant was recommended for funding by the Ecology Program. This funding will allow Sally to expand her research at Konza Prairie and in Kruger National Park, South Africa.

Project Summary: Intellectual Merit: Humans are altering the environment locally and globally through climate and land use change. Global temperature is increasing, precipitation patterns are becoming more variable, disturbance regimes are being altered, and ecosystems are being simplified as multi-species communities are replaced by monocultures of crops or livestock. Grasslands, which cover approximately one third of the terrestrial lands, are ecologically and economically significant, thus their responses to environmental change will have dramatic consequences for global patterns of productivity, biodiversity, and food production. This dissertation research investigates how changes in these three main drivers of mesic grassland ecosystems – precipitation, grazing, and fire - interact to affect community composition, structure, and dynamics.
Currently this dissertation research investigates the interactive effects of (1) grazing and fire, and (2) grazing and precipitation on plant community structure in North American (NA – Konza Prairie, KS) and South African (SA – Kruger National Park) savanna grasslands. Funding from NSF will significantly enhance this dissertation by aiding in the addition of two experiments. The first experiment will investigate the interactive effects of all three drivers – grazing, fire, and precipitation – on plant community structure in NA and SA. The second proposed experiment will assess how small-scale patch structure and dynamics in SA grasslands respond to fire along a grazing utilization gradient. Preliminary results show that grass patch structure has no relationship to forb richness or cover, yet higher plant species diversity is found in more heavily grazed areas in both NA and SA. The second experiment will provide information that will help tease apart how fire and grazing intensity alter grass-forb interactions in SA. Little is known about how climate, fire, and grazing interact to affect community properties especially in SA. The current and proposed research will illuminate processes affecting community structure in mesic savanna grasslands that are predicted to experience more extreme droughts, altered fire regimes, and loss of herbivore diversity.