We are beginning new studies of phenology at the Andrews Forest to better understand influences of existing complex climatic gradients on timing of springtime life history events for multiple trophic levels. Phenological events are highly sensitive to temperature and climatic variations and are some of the most responsive indicators to climate change. By studying timing of events at multiple sites in a very heterogeneous climatic landscape, we expect to learn much about plant, insect and bird responses to current abiotic variability (i.e.

Alliaria petiolata (garlic mustard) is an herbaceous biennial herb that has been present in the New England landscape for over a century. We investigated the ecological and historical factors affecting A. petiolata's invasion pattern across the New England landscape, including forest community structure, geophysical attributes, and habitat fragmentation. One-hundred-and-seventy-five 25× 100 m roadside, forested plots across two ecoregions were visited in the summers of 2006 and 2007. A. petiolata presence and cover, dominant canopy species, slope, and soil moisture were recorded.

How will anticipated changes in climate interact with grassland plant community composition and diversity to affect the performance of seedlings? We ask this question for two reasons. 1) If plant species are to track spatial shifts in the locations of suitable climatic conditions, plant species must invade communities by means of seedling establishment; more diverse plant communities have been shown to be less invasible, but it is not known how warming will interact with diversity to affect invasion.

The Sevilleta LTER is located at the intersection of several aridland ecosystem types. Although it is axiomatic that water is the key limiting resource in aridland ecosystems, most arid land soils are also chronically low in nutrients and organic matter. Resource availability is a function of the frequency and size of precipitation events as well as the time between events. As a consequence, NPP and organic matter decomposition are often decoupled in space and time, and soil nutrient supply rates may limit NPP during periods when soil moisture is sufficient for plant growth.

Background/Questions/Methods

The Virginia Coast Reserve (VCR) is an extremely dynamic, heterogeneous coastal barrier landscape comprising mainland watersheds, tidal marshes, lagoons, and barrier islands. Our goal for the VCR LTER program is to develop a predictive understanding of the response of coastal barrier systems to long-term environmental changes in climate, sea level and land use, and to relate these to the ecological services the coastal barrier systems provide.

The Luquillo Forest Dynamics Plot (LFDP) is a 16-ha long-term study plot in subtropical wet forest in the Luquillo Mountains of Puerto Rico. It is part of the Luquillo LTER and the Center for Tropical Science (CTFS) network of large tropical forest plots. Forests are often subject to multiple, compounded disturbances, representing both natural and human-induced processes. Our goal is to understand forest structure, diversity and dynamics, and to predict long-term changes resulting from interactions of past human land use and intermittent hurricane damage.

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.

The Chicago Region ULTRA-Ex will address a question fundamental to understanding the dynamic interactions between biodiversity conservation, ecosystem processes, and human well being in urban landscapes: In a complex urban/metropolitan system, what are the synergies and tradeoffs between conserving biodiversity and providing ecosystem services to people? The project focuses on the Green Infrastructure Vision of the Chicago Wilderness alliance, a conservation consortium of over 240 organizations.

Some non-native invasive plant species are well suited for spread in forest-dominated landscapes and may pose a threat to forest communities. We determined the local and regional factors which the distribution of such species, in order to better understand the invasion process and to identify areas that are particularly susceptible to invasion. We conducted roadside surveys to determine the presence/absence and abundance of 15 non-native plant species known to invade forests in western North Carolina.