Ecosystems in topographically complex (mountainous) terrain are responsible for a majority of land-atmosphere CO2 exchange (net ecosystem exchange; NEE) across the western United States due to high inputs of winter precipitation as snowfall. NEE in these regions has been historically difficult to quantify using the eddy covariance (EC) method, however, due to complexities in surface terrain that lead to irregularities in streamline air flow, particularly advective fluxes during periods of low turbulent mixing.

Urbanization is one of the major threats to stream ecosystems worldwide. The phrase “urban stream syndrome” has been coined to describe patterns in degraded streams draining urban land. In Puerto Rico, urbanization now covers 16% of the island. The fully protected Luquillo Experimental Forest (focus of the LUQ-LTER) is only 23 km from the center of San Juan, a city of 1.3 million. Therefore, LUQ is assessing the impacts of urbanization on tropical stream ecosystem structure and function.

Despite substantial changes in climate, sea-ice and glacier extent, and vegetation in much of the Arctic, the area near Toolik Lake, Alaska has experienced no significant trends of increasing temperature, altered precipitation, or increasing active-layer thaw depth. There has been, however, a near doubling of alkalinity in Toolik Lake since 1975 and increases in alkalinity in many lakes of all depths and sizes in the surrounding area. Lake monitoring indicates that in-lake processes such as sulfate or nitrate reduction cannot account for these alkalinity increases.

Fragmentation of natural habitats, driven by urban growth and other land use modifications, acts to decrease the amount of core habitat as well as the connectivity among core areas. As a result, landscape fragmentation can have negative impacts on the ecological communities, ecosystem services, and metapopulation dynamics.

Cities are specific environments for testing paradigms related to water, biodiversity and resource management. Permanent interaction of a number of factors: anthropogenic, natural, social and economic, imposing pressures on environment and raising quality expectations, makes development and effective implementation of new theories and foundings a real challenge. Another challenge is general lack of paradigm linking water management and biodiversity management in urban areas.

As demonstrated in many studies, mostly in rural settings, successful resource management requires collaboration among many groups. This is likely to be even more pronounced in densely settled urban areas. Cities generally consist of many fragmented land parcels under different types of use and ownership, which produces a large and diverse group of stakeholders with an interest in resource management decisions.

Environmental justice research seeks to understand the patterns and processes shaping the distribution of environmental burdens and amenities across society. While environmental justice research in the US has generally focused on toxics, urban design, hazard management, and segregation have reshaped patterns of risk associated with environmental processes, such as flooding, and the social patterns of exposure to those risks. In Baltimore, flood risks have been a major impetus behind the engineering of the hydrologic systems of the city.

Climate change, residential development, and timber harvesting are likely to be the primary disturbance agents affecting the forests of Massachusetts in the coming decades. One source of uncertainty is the potential rise of a forest biomass energy industry and the ensuing increases in harvesting to meet demand for feedstock. Under Massachusetts’ Renewable Portfolio Standard, potential future demand for biomass electricity could be around 165 MW, which would require up to 2 million Mg of woody biomass annually.

Ecosystems worldwide are faced with climate change. In the northeastern United States, climate change is coupled with nitrogen deposition from air pollution. The objective of this study is to determine how soil warming and nitrogen deposition influence species richness, diversity, and abundance of vegetation in a northeastern forest. Our study site is the chronic Soil Warming and Nitrogen Fertilization experiment at the Harvard Forest Long Term Ecological Research site.

Numerous physical, chemical, and biological processes operate in positive feedback loops during the invasion of C3 shrubs into C4 grasslands. These processes occur at multiple spatial and temporal scales, ranging from a few mm2 over a period of weeks to hundreds of km2 over a period of millennia.