Increasing atmospheric CO₂ will likely affect both the hydrologic cycle and ecosystem productivity. Current assumptions that increasing CO₂ will lead to increased ecosystem productivity and plant water use efficiency (WUE) are driving optimistic predictions of higher crop yields as well as greater availability of freshwater resources due to a decrease in evapotranspiration.

Oribatid mites are among the most diverse soil mesofauna, and they possess a variety of metabolic and morphological feeding adaptations. Unfortunately, our understanding of the mechanisms by which oribatids may influence decomposition dynamics is incomplete. A microcosm experiment was conducted in which corn and oak leaf litter were incubated in the presence and absence of actively feeding oribatid mites Scheloribates sp. Our objective was to quantify the effects of Scheloribates sp. on microbial activity and carbon cycling within litter.

Recent ¹⁵N tracing studies have highlighted the important role biotic assimilation plays in stream N retention, yet the fate of N following assimilation is not well understood. One potentially important fate is indirect denitrification, a process in which locally mineralized and nitrified N is denitrified before being exported to the water column. We conducted a series of in-situ chamber experiments in which patches of stream bottom were labeled with ¹⁵N to investigate the fate of assimilated N.

Population growth and urban sprawl are two issues that have long concerned environmentalists. Another, more modern phenomenon is that of urban to rural migration, wherein residents of urban or suburban areas buy property in areas more rural, less developed. This study is concerned with the land use decisions made by these new rural residents. The study is centered in Southwest Michigan, Barry Township within Barry County. The area is one of shifting land use patterns and increasing residential development.

Impact of Agricultural Practices on Bacterial Carbon Use Efficiency
Z. M. Lee and T. M. Schmidt
Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI

Humans make decisions daily that impact biodiversity, and it is essential that citizens understand the implications of these decisions. Yet, ecological systems are extremely complex, with many details still being discovered. Our challenge is to identify the underlying principles and concepts governing the distribution of organisms, and then communicate these details to students in a way that influences their citizenship decisions as participants in local and global communities. 

Many ecosystems, including grassland, forest, alpine, and desert, have shown responses to N enrichment. These responses vary considerably but include changes in soil respiration rates, enzyme activities, and microbial community structure. Surprisingly, little work has examined the effects of N enrichment on soil communities and processes in agricultural systems despite the high rates of N applied in most crop production systems.

The KBS LTER site is in a diverse, rural-to-semirural landscape typical of the U.S. Great Lakes and upper Midwest regions. Research at KBS asks how diverse plants, animals, and microbes in agricultural landscapes can contribute to farm productivity, environmental performance, and profitability. We study annual and perennial crops including corn, soybean, and wheat rotations, forage crops such as alfalfa, and biofuel crops such as poplars, switchgrass, and native successional communities.

Landscapes provide ecosystem services to agricultural systems by supporting pollinators and predators of crop pests, services valued at $US 3 and $US 4.5 billion/yr respectively. Habitat management is the practice of providing nectar, pollen and shelter to beneficial insects in cropping systems, often in the form of flowering strips. However, the potential for flowering strips to increase biocontrol and pollination depends on the existing abundances of beneficial insects in the landscape, and highly simplified landscapes may support fewer beneficial insects than more diverse landscapes.