The project titles and abstracts for each graduate fellow are organized alphabetically within their year of award.
For an alphabetical list of all fellows, click here:
Fellows Project Overview
To read project abstracts, click on the fellow's year of award:
2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | 1998
1998 Awards
Dana Blumenthal
Awarded 1998, Renewed 1999, 2000
University of Minnesota, Agronomy Dept.
Major Professor: Nick Jordan
Does prairie restoration control weeds? The interactive effects of ecological restoration, resource addition and litter removal on weed invasion
Current weed control practices are both self defeating and environmentally unsound. Ecological theory suggests that ecosystem restoration could provide long term weed control while increasing biological diversity. The experiment proposed here will measure the weed control benefits of prairie restoration and examine two hypotheses that might explain those benefits: resource competition and safe site availability. By doing so it will provide insights into both the degree to which and mechanisms by which analogs of natural ecosystems are able to reduce weed invasion. 20 weed species will be seeded into replicated plots of restored prairie and old field. Subplots will be treated with all combinations of nitrogen addition and litter removal. Weed biomass will be measured one and two years after seed addition, and the interactive effects of restoration, nitrogen addition and litter removal will be examined.
Robert Corry
Awarded 1998, Renewed 1999, 2000
University of Michigan, School of Natural Resources and Environment
Major Professor: Joan Iverson Nassauer
The role of small-patch perennial agriculture in enhancing landscape ecological health
The ecological health of agricultural landscapes is altered by the large-scale cover types, practices, and management associated with much of contemporary agriculture. Aggregation of fields into larger blocks of similar management systems has often resulted in decreased biodiversity. Annual crop systems common in many areas of the nation typically incorporate technologies that reduce variability among nutrients, flora, and fauna. Our cropped landscapes are simply managed to reduce diversity.
Small-patch agriculture systems could re-introduce perennial plants into annual crop system landscapes. Perennial cover would result in increased floral diversity and probable increased faunal diversity. Designing for small-patch perennial agriculture systems could improve ecological health over current annual crop systems. This research investigates how small-patch agriculture could fit into landscapes dominated by annual crop systems by altering attributes of landscape ecological structure. It further compares the ecological health of a current landscape without small-patch perennial agriculture to a prospective landscape designed to increase ecological functions through inclusion of small-patch perennial agriculture.
Charles Mitchell
Awarded 1998, Renewed 1999
University of Minnesota, Dept. of Ecology, Evolution and Behavior
Major Professor: G. David Tilman
The role of plant disease in native grassland: Implications for Natural Systems Agriculture
Disease would often severely limit the production of modem agricultural systems were it not for the ubiquitous application of chemical control agents, yet a major goal for natural systems agriculture is minimizing such chemical inputs. In low-input production systems modeled on nature, will the effects of disease on production still be strongly limiting, minimal but still negative, or qualitatively different from modem agricultural systems? I am addressing this question by investigating feedbacks between disease and the plant community in a species-diverse perennial grassland, the model ecosystem for midwestern natural systems agriculture. Using this approach, I have begun to answer several more specific questions about disease in natural systems agriculture: Will higher plant species diversity reduce losses to disease? Will disease limit total production of perennial polycultures? Will disease limit production of some of the component species of perennial polycultures, determining their respective yields? Will disease promote coexistence of these component species? Will controlled burning be a useful tool for managing pathogen populations? Answering these questions will begin to outline the role of plant pathology in natural systems agriculture.
Corey Samuels
Awarded 1998, Renewed 1999
University of Tennessee, Dept. of Ecology and Environmental Biology
Major Professor: Mark Kot
Modeling community assembly for Natural Systems Agriculture: Toward prescriptive guidelines for creating specific communities
Agricultural systems modeled on the structure of natural communities must be comprised of specific desired species in combinations that persist over time. Computer models of community assembly have led to the idea that the steps of development, the timing and order of species introductions, can play a key role in determining community composition (see Drake 1989 for a review). These assembly rules are derived from computer models and laboratory experiments, but less is known about their role in specific natural systems (Samuels and Drake 1997, Samuels and Hewitt in prep). The Land Institute's (TLI) field experiment in community assembly incorporates assembly principles in constructing natural systems agriculture cropping systems. Here, I propose to develop simulation models of grassland community assembly that will build upon and complement this theoretical and applied work. These models will test the robustness of previous assembly rules and contribute prescriptive guidelines for community construction. These simulations are specific to grasslands, using a mathematical model of plant succession by competition for light and nutrients. Prairie species will provide the parameters, and the results can be compared with data from the experiment at TLI. I will do the computer modeling at the University of Tennessee. I will measure some parameters in the field and greenhouse at TLI and derive some from the literature. The result will be a new tool for natural systems agriculture in the Great Plains. Ultimately, it will be possible to adapt this model for use in other regions.
Dan Wildy
Awarded 1998, Renewed 1999, 2000
University of Western Australia, Department of Botany
Major Professor: John Pate
Comparison of water use of two remnant Eucalyptus woodlands with oil mallees planted on farmland for hydrologic control
I propose to investigate the water cycling in a Eucalyptus loxophleba subsp. lissophloia (smooth-barked york gum) woodland in the Western Australian wheatbelt so that these processes may be incorporated into the design of sustainable farming systems. York gum grows naturally over a large area of the eastern wheatbelt, often in monospecific stands with a herbaceous understorey (Mattiske, 1995). Much of this land has been cleared (>90%) for grain growing and now suffers from rapidly rising saline water tables since the hydrological balance has been altered. It is currently thought that 30% of the wheatbelt will be affected by salinity in the next 30 to 50 years (Ferdowsian 1996). Contrasting this, the vegetation prior to clearing was characterized by morphological structures which functioned to provide long-term stability of soil and hydrology (Lefroy et al. 1993), however, these are poorly understood.
I aim to determine the sources and amount of water used by a york gum community throughout the year and the physiology behind the use of this water within the plant. The specific questions to be answered will be:
- what are the main functions in the natural ecosystem responsible for hydrological stability,
- how would these functions be best replicated in a farming system, and
- how closely must the original vegetation be mimicked for the farming system to be sustainable hydrologically?
I propose to utilize new stable isotope techniques involving 13C and deuterium, as well as neutron moisture meter probes, sap flow meters and collection of climatic and seasonal plant growth data to follow seasonal trends in capture and cycling of water by the dominant woody species.
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