LTER: From Microbes to Macrosystems: Understanding the response of ecological systems to global change drivers and their interactions

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For thirty years the Harvard Forest Long Term Ecological Research (LTER) program has been dedicated to understanding New England's forests. The heart of the program is a group of scientists and students who do experiments and measure the many ways that forests change over time. They are especially interested in how forests are linked to society. In the next six years they will study how forests respond to changes in climate, the spread of invasive species, and use of land by humans. Scientists will start some new studies and continue others, all connected by what they'll reveal about how and why forests change over time. Many of the studies have been designed in partnership with natural resource professionals to ensure that they help solve real-world problems. Scientists will mentor college students from many backgrounds, who will work together in interdisciplinary teams. The students will learn new skills and collect important data. Public school teachers and students in their classrooms will also be engaged through activities at Harvard Forest. Data from a network of permanent forest plots will continue to document long-term changes in forest characteristics and provide validation sites for three eddy-flux towers, multiple remote sensing observations, and an integrated modeling framework. This network will be augmented by a new system of soil ecology plots and a 35-hectare stem-mapped forest dynamics plot. Collectively, the plot-based studies will be used to describe the drivers of primary production, composition, and structure across broad scales of space and time. To understand the consequences of observed trends in climate and atmospheric chemistry, the LTER program will continue to support a long-running suite of soil warming and chronic nitrogen addition experiments. In addition, paleoecological studies, based on analysis of pollen in lake cores and of tree rings, will be coupled to simulation models to test hypotheses related to the long-term influence of climate on forests. The researchers will build upon their 20-year history of studying hemlock-decline due to an invasive insect by including observations of the changes in belowground microbial communities, stream biochemistry, and the regional pattern of hemlock loss based on a 30-year Landsat time-series. Studies to understand the consequences of invasive insects will be expanded to the newly arrived emerald ash borer and the reemergence of gypsy moth. The Harvard Forest continues to maintain some of the world's canonical studies of human land-use impacts on forest ecosystems, spanning the persistent legacies of colonial agriculture to the modern land-use regime. LTER studies of land-use impacts will be expanded to the scale of New England, using diverse remote sensing platforms, forest inventory databases, and spatial modeling, to understand how the spatio-temporal patterns of land use affects forest dynamics. Finally, the LTER program will continue to support the development of a regional simulation framework that projects the individual and interactive effects of global change drivers on the New England landscape.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.