Here are our 2006 cluster descriptions. Click on the links to get to abstracts for the projects that were conducted over summer.
Biodiversity, predation, and competition
What controls species coexistence and biodiversity, whether in bacteria or bats, are among the great puzzles of our time? How prey cope with predators, and how they compete for food play key roles in governing the coexistence and biodiversity of prey communities. Important pieces of these puzzles are missing, so this cluster will explore what we already know and what science needs to know about these connected issues. Students will perform field and/or laboratory experiments designed to find and perhaps orient these puzzle pieces to help increase our understanding of how competition and predation control coexistence and biodiversity.
Remote sensing of forest landscapes
The composition of forest stands may be an important determinant of the species composition of consumers and of landscape and ecosystem processes, including biological invasion. While tree and shrub composition can be determined directly by field sampling, this is impractical for large, landscape scale studies. We seek to explore the potential of remote sensing to describe patterns of canopy tree composition and understory shrub invasion in deciduous forest stands. Satellite images of reflectance patterns are widely used to distinguish different land cover types, including coniferous vs. deciduous forest, but there has been little application to finer scale vegetation classification in our area. We plan two collaborative investigations to advance the resolution of vegetation patterns. 1) Determine the patterns of reflectance that correspond to the abundance of the invasive shrub, Lonicera maackii (Amur honeysuckle), in forest understory (Gorchov & Henry). This shrub is likely to be detectable in satellite images from the spring and fall, because its leaves emerge earlier in the spring than those of native canopy trees and deciduous woody plants (about six weeks earlier in Ohio), and are retained later in the fall (about one month later in Ohio). A series of forest stands near Oxford that span a wide range of L. maackii density will be selected, and current L. maackii cover will be quantified. Satellite data for these areas will be obtained from free sources such as OhioView (http://www.ohioview.org/data/) and the University of Maryland’s Global Land Cover Facility (http://glcf.umiacs.umd.edu/index.shtml). 2) Determine the patterns of reflectance that correspond to the canopy tree composition, and relate this to moth species composition (Crist & Maingi). Because different tree species leaf out and drop leaves on different dates, there is potential to estimate canopy composition by analyzing a temporal series of satellite images. Canopy composition was shown by Summerville & Crist to influence the composition of the moth community in southern Ohio. We propose to quantify the tree composition in a set of stands near Oxford, likely overlapping with the set for Question 1, and use these as “training” data for the satellite images. The “training” data will be used together with recent multitemporal Landsat ETM+ data, image enhancements, and topographic data derived from a DEM, to construct a regression tree algorithm that will be used to model forest canopy composition. Once constructed, the regression tree algorithm will be used to predict forest stand composition within the study area. The accuracy of the predicted canopy composition map will be assessed using stand data previously gathered by Summerville and Crist (2004). Finally, we will test how well the predicted canopy composition explains the composition of the moth community, using data of Summerville & Crist.
Interactions between lakes and their surrounding landscapes
Lakes are embedded in landscapes. The water that fills them comes from those landscapes. Thus, lakes are greatly influenced by their watersheds and can serve as integrators of landscape processes and activities. Features of the surrounding landscape, especially human activities, may strongly affect the quantities of nutrients, sediments and pesticides entering lakes, as well as what species of plants and animals occur in the lakes. Landscape features may also determine the quantity and quality of carbon delivered to lakes, and lakes in turn may mediate the downstream transport of carbon. The role of lakes in mediating carbon dynamics has important implications for global climate change. Students in this cluster will focus on various aspects of landscape-lake interactions. In particular students will assess how land use (forest, agriculture and/or urban areas) affects the delivery of nutrients, carbon, sediments and pesticides to lakes, the consequences of these inputs for various aquatic species, and how lakes mediate the cycling and downstream transport of nutrients, carbon and pesticides. Students will be encouraged to develop projects that fit into this overall scheme, but which reflect students’ particular backgrounds and interests.
Animal behavior
Humans impose themselves on landscapes in a variety of very obvious ways. It is easy to see the changes we inflict on natural habitats as we destroy forests to build houses and roads. What is less obvious, especially for species adapted to coexist with humans, are the behavioral shifts that occur in response to our presence that can have long term effects on the survival of a species. The students in this cluster will explore the behavioral ecology of diverse species including rodents, ants and spiders, to understand what factors might affect survival, foraging and/or successful reproduction. Students will use basic techniques for censusing their study organism in natural systems, which might include trapping for mammals, looking in the nighttime for eyeshine of spiders or other basic censusing techniques. In addition, each project will entail a manipulation to determine how a specific environmental shift changes some aspect of the behavior of their study species. For example, students might look at how predation risk affects courtship and sexual selection in a wolf spider, how detritus or dead insects (e.g. the large numbers of cicadas that flourished and then died a few years ago) affect the foraging of ants, or they might explore the social structure of a rodent species to understand if and when they might be monogamous. These projects were not cast in stone and we gave participants some latitude in developing a specific question to address. Key topics include behavior, reproduction, foraging, arthropods, mammals, social structure, sexual selection.
