Sustainable management in a changing world
CURRENT RESEARCH
Biological Control of the Emerald Ash Borer
Gruner Lab, University of Maryland
The emerald ash borer (EAB) is beetle that has invaded 35 states in the U.S and multiple Canadian provinces. As it's name suggests, EAB feed on species of ash with adults eating the leaves while the larvae feed on the inner bark by boring holes. Larval EAB do considerable damage to ash trees by disrupting the tree's flow of water and nutrients and have killed hunderds of millions of ash trees in North America.
To reduce the population of EAB, the United States Department of Agriculture (USDA) Animal and Plant Health Insepection Service (APHIS) has created a release program using four parasitic wasps that are natural enemies to the EAB in it's native range. In my research I assess the establishment and spread of these four parasitic wasps species as we try to determine their effectiveness as biological control agents of EAB.
Arthropod Community Responses to Cattle Grazing Intensity in Northern Mixed-Grass Prairie
Koerner Biodiversity Lab, University of North Carolina at Greensboro
Herbivory plays a vital role in shaping plant communities–altering plant growth rates and selecting for specific plant species or traits. Within an ecosystem, there are multiple herbivore types competing for resources, resulting in interactions between herbivores, such as those between mammals and insects. The ‘Trophic Level’ hypothesis states that the effects of herbivorous mammals on the plant community indirectly alter the insect community composition because insects are highly reliant on the food, shelter, and oviposition that their plant hosts provide. Large grazers, like cattle, typically reduce insect abundances.
My research explores the role of cattle grazing intensity in shaping insect communities leading to a better understanding of how to preserve the rangeland ecosystem. In particular, I am addressing the following questions: (1) Does grazing intensity affect insect herbivore communities? and (2) Does this pattern change temporally as precipitation regimes change from year to year?
Plant Community Responses to Multi-Year Drought on Working Rangelands
Koerner Biodiversity Lab, University of North Carolina at Greensboro
In rangelands such as the mixed-grass prairie (MGP) in the United States Great Plains, disturbance affects on plant communities are typically studied using plant species composition (proportion of each species present) and/or plant functional traits (attributes that affect plant fitness). However, when considering that droughts are increasing in severity and intensity and cattle grazing pressure is increasing, it is important to understand how ecosystem function may be affected. By combining plant species composition and functional traits, we can determine community-weighted means of each trait and functional diversity. This will allow us to scale up from organismal level fitness to community level fitness. Ultimately these data will assist land managers in making management decisions based on multi-year droughts to maintain the sustainability of MGP.
My research addresses this need to understand the interaction of multi-year drought and cattle grazing intensity, in particular determining how ecosystem function may be affect by measuring community-weighted means and functional diversity.
Fire Disturbance in Tallgrass Prairie: A Meta-Analysis
The Nature Conservancy and University of North Carolina at Greensboro
The North American tallgrass prairie-an ecosystem dependent on fire and grazing disturbance-is one of the most endangered ecosystems in the world. Throughout history, people have leveraged fire as a means to manage grasslands and grazers for food. While in the recent past, fire has been suppressed, it is clear now that prescribed fire can be a necessary tool in tallgrass prairie restoration and management. While many studies have addressed how fire alters particular ecological impacts, we do not have a full understanding of how fire return intervals (time between prescribed fires) alter a large suite of ecological impacts.
In this meta-analysis, we seek to fill this gap by examining the impacts of prescribed fire on multiple ecosystem properties, including soil carbon and nitrogen storage, microbial biomass, woody encroachment, invasion, and insect, bird, small mammal, and plant communities across the North American tallgrass prairie. Primarily, we are asking how different prescribed fire regimes affect multiple ecological outcomes and how these effects differ by climate or landscape within tallgrass prairie.
While working as a fellow at The Friends of Nachusa Grasslands with Dr. Elizabeth Bach this portion of my research will address how different prescribed fire regimes affect multiple ecological outcomes and how these effects differ by climate or landscape within tallgrass prairie with the goal of assisting land managers in fire management decisions based on their needs.
Legume Invasion Success: A global meta-analysis
Komatsu Ecosystem Conservation Lab, Smithsonian Environmental Research Center
There are estimated to be more than 1,000 invasive species worldwide and generalists are theorized to be more successful as invaders due to the lack of specialized niches which promotes their success in a wide variety of habitats. While this theory can apply to all aspects of a species’ life history (e.g., habitat preference, resource use, etc.), it may be particularly relevant to non-native species that rely on mutualists during their life cycle. The legume-rhizobia mutualism is an ideal model system to test the hypothesis that non-native species should be mutualistic generalists, as plants in the legume family frequently form mutualistic associations with rhizobia and they are prolific invaders world-wide.
Working with Dr. Kim Komatsu at the Smithsonian Environmental Research Center, we are performing a meta-analysis using data compiled from 255 articles published between 1984-2014. We are asking the question: Are non-native legumes more commonly rhizobial generalists or specialists?
PAST RESEARCH PROJECTS
My interest in ecological research began during sophomore year of my undergraduate studies and from that moment on, each research project I was involved in, whether at Eastern University, The Kellogg Biological Station, or the Smithsonian Environmental Research Center, had a part in developing the research interests that I pursue today.
Effects of White-Tailed Deer on the Plant Community Composition in Tallgrass Prairie
Komatsu Ecosystem Conservation Lab, Smithsonian Environmental Research Center
Grasslands worldwide are diminishing in area and understanding the drivers shaping the remaining grasslands is critical for their maintenance and to conserve the ecosystem services and biodiversity that they promote. North American tallgrass prairie in particular, covers only about 13% of its historical range. Shaped by fire and herbivory disturbance, tallgrass prairie historically was grazed by bison. However, bison have been nearly eradicated, leaving deer as the primary large bodied herbivore in this ecosystem. Due to the differential feeding preferences of bison and deer, it can be hypothesized that deer alter the plant community in a different way than bison have in the past. Therefore, we addressed two main questions: (1) What are the impacts of deer on plant diversity, species identities, and relative abundances? and (2) Is there an interactive effect between the pressures exerted by deer and the well documented effects of fire in driving plant community responses?
After two decades of deer exclusion in the uplands of Konza Prairie Biological Station and Long Term Ecological Research site, we found that exclusion did not have an impact on herbaceous plant community composition, including plant species richness, evenness, and functional group composition. Further, our results indicated that the competitive dominance of C4 grasses in the absence of bison may constrain the impact that deer herbivory has in the tallgrass prairie ecosystem.
An examination of root exudates on soil denitrification
While earning my Bachelor of Science in biology from Eastern University I was awarded a SEEDS Partnership for Undergraduate Researchers (SPUR) Fellowship position from The Ecological Society of America (ESA). As part of this position, I spent three months as a National Science Foundation Research Experience for Undergraduates (REU) intern at the Kellogg Biological Station. There, I worked in Dr. Sarah Evans’ lab to develop and execute a research project to more comprehensively determine if switchgrass is a sustainable biofuel. This experience gave me the opportunity to present at my first three scientific symposiums--the Kellogg Biological Station’s Annual Undergraduate Research Symposium, the World Congress on Undergraduate Research in Qatar, and the 2017 ESA Annual meeting.
Nematode Research
While earning my Bachelor of Science in biology from Eastern University I worked with Dr. Benjamin Dube and conducted research assessing effective biological control agents for root-knot nematodes on tomato plants. While working with Dr. Dube for 2.5 years, I also taught new student researchers root-knot nematode extraction techniques and assisted with research project development for new students. Further, I presented this work at the St. Joseph's Sigma Xi Research Symposium. As my first experience in ecological research, I not only learned skills specific to my research, but also developed scientific writing skills, oral and written presentation skills, and expanded my knowledge of the scientific process.