West Nile virus (WNV) was first detected in the western hemisphere during the summer of 1999, reawakening U.S. public awareness to the potential severity of vector–borne pathogens. American crows (Corvus brachyrhynchos) are a highly susceptible WNV host, and spatio-temporal changes in crow abundances can serve as a proxy for the latent (unobserved) WNV prevalence in host populations. Crow population dynamics in the five years before and after WNV emergence were modeled from Breeding Bird Survey (BBS) data for the eastern US. Crow declines following WNV emergence were found to be significantly associated with reduced forest cover and higher urban land use, as well as with above-average local winter temperatures. However, urban cover and winter temperature deviations did not vary independently and sites with more urban land cover were generally warmer than more rural sites within the same latitude. Although these findings support an urban-pathogen link, the current study highlights the need for greater understanding of how interactions between structural land-use patterns and climate regulate WNV amplification in host and vector communities to support pathogen persistence in the environment.

Pollination is a valuable ecosystem service, providing a variety of benefits including food and fiber, plant-derived medicines, ornamentals and other aesthetics, genetic diversity, and overall ecosystem resilience. The issue of pollinator declines began to receive widespread attention in 2006 when the popular press reported on the mysterious disappearances of managed honey bee colonies across the U.S.

At the global scale, declines in pollinator populations and species diversity more broadly have raised concerns regarding potential risks to global food security and economic development, particularly in countries where agriculture is a large portion of the economy. We synthesize the literature on pollinator declines with the objective of characterizing the associated risks, and quantifying what those risks might mean in terms of adverse shocks to yields in different crop categories and regions. We then briefly review existing methods for valuing such shocks before introducing a novel general equilibrium assessment approach and highlighting a few of its preliminary results.

This presentation will summarize results from three regional studies conducted over the last four years to investigate climate's influence on floods: (1) flood magnitude trends at New England stream gauges; (2) flood frequency trends at New England stream gauges (in collaboration with Boston College); and (3) an evaluation of the precipitation events that caused each flood event in the record of selected New England and Atlantic Canada stream gauges (in collaboration with NOAA's National Climatic Data Center, Cornell University, and Environment Canada). The potential influence of the North Atlantic Oscillation (NAO), a large-scale upper atmospheric circulation pattern, will be discussed as will implications for predicting the magnitude and frequency of future floods.

Acid deposition during the 20th century depleted base cations in the northeast United States and around the globe, substantially altering terrestrial ecosystem function. To understand ecological response to depleted calcium (Ca) soil concentrations, watershed 1 (W1) at the Hubbard Brook Experimental Forest was amended with enough Ca to bring soil Ca concentrations to pre-industrial levels. Following the amendment, the hydrology of W1 changed; annual evapotranspiration (ET; calculated as the difference between precipitation and runoff) increased by 25%, 18%, and 19% respectively for the three years following treatment, followed by a return to normal ET rates ever since. Concurrently, stream water chemistry changed, showing high Ca retention following the wollastonite addition. We hypothesize that trees in W1 responded to the Ca amendment through a few possible mechanisms that stimulated transpiration for the three years following treatment. Hydrologic change resulting from the Ca amendment suggests that historical and future changes to soil Ca concentrations may have concurrently altered or will alter water cycle dynamics.

Producing knowledge and linking it to actions that meet human needs while preserving the planet's life-support systems has emerged as one of the most fundamental and difficult challenges of our time. There is growing consensus that traditional methods of generating and using knowledge must be fundamentally restructured to confront the breadth, magnitude, and urgency of many problems now facing society. Maine's Sustainability Solutions Initiative (SSI), which is supported in part by a $20 million NSF EPSCoR grant, represents an institutional experiment designed to learn how research universities can contribute more effectively to the solution of pressing societal problems with intersecting ecological, social and economic dimensions.

SSI is guided by a belief that efforts to solve sustainability problems require unprecedented levels of program integration and organizational learning, including a deep commitment to interdisciplinary teamwork, robust stakeholder – university partnerships, and an innovative institutional culture. SSI's approach to advancing the theory and practice of sustainability science involves three interrelated areas of research: 1) investigating the dynamics of coupled social-ecological systems; 2) examining and improving links between knowledge and action; and 3) analyzing and fostering organizational innovation. SSI's initial focus is on landscape dynamics, with particular emphasis on three interacting drivers of landscape change (i.e. urbanization, forest ecosystem management, and the climate/energy nexus).

To date, more than 70 faculty with diverse expertise from UMaine, University of Southern Maine, and many other Maine colleges and universities have begun working together to develop creative solutions to challenging problems involving town planning processes, management of the North Woods, renewable energy development, and other pressing issues. Our partners include towns throughout Maine, tribal communities, NGOs, state and federal agencies, business and industry, and many others. After explaining SSI's rationale, strategy, and goals, I will describe some of the challenges and opportunities we have encountered in using Maine as a laboratory for accelerating the transition to sustainability.

Northeastern US forests are important sinks for rising concentrations of atmospheric CO2. Climate-carbon cycle connections are well established but the constraints imposed by the N cycle on the C sink remain poorly understood and articulated in current-generation conceptual and quantitative models. This talk will provide a brief history of the (dis)connections between the biogeochemical cycles of C and N, and then present work from New England forests which provides a basis for linking the N cycle to C cycle in a manner that could be incorporated into models. In our studies, we find the temperature sensitivity of enzyme activity and belowground C allocation by trees are critical to C balance of forest ecosystems through their effects on soil organic matter decomposition and the release of organic forms of N which support net primary production.