The Harvard Forest LTERV Program: Long-term trajectories and new results

Background/Question/Methods

The goal of the Harvard Forest LTER-V is to apply its site-to-regional-scale strengths in research, education, and outreach to address a fundamental research question: What will be the interactive effects of climate change, biological processes, and human land-use on ecosystem dynamics, processes, and the services they provide to humans and wildlife over the next 50 years? Integrated scenarios analyses provide scientists and decision makers a structured framework for understanding a complex world. Landscape simulations  link a range of stakeholder-defined scenarios describing plausible future conditions with socio-ecological and environmental drivers based on new and long-term monitoring and experiments. The consequences of multiple stressors on forest dynamics and ecosystem processes are evaluated in terms of their effect on ecosystem services (carbon, water, wildlife etc.). The inclusion of diverse stakeholders in the production of the scenarios, and public outreach of those results, fills critical knowledge gaps for scientists and the public, and helps decision-makers better use science to address societally relevant questions.

Results/Conclusions

Here, we highlight new results and how they provide insights to the scenarios framework.  For example, eddy-flux measurements and phenological observations combined with modeling show that increasing CO₂ levels and longer growing season partially drive increasing carbon uptake by the forest ecosystem over the past two decades. Synthesis of permanent plot data show how forest development and species composition also contribute to this trend. Paleoecological reconstructions of abrupt vegetation and climate change put these results into a 15,000 year context.   How species and trophic effects control ecosystem function are the subjects of ongoing research on moose and deer browsing, microbial communities, and foundation species loss. Landowner survey studies illuminate the drivers of the decision-making process that leads to timber harvest and land conservation across urban-rural gradients. Analysis of land fragmentation shows that ‘hot-spots’ of ecosystem services are becoming more concentrated. These socio-ecological inputs are used in a landscape modeling framework, and scenario development is underway for New England, utilizing a coordinated network of scientists and practitioners from across the region. Results are communicated with targeted audiences via the Science Policy Exchange, graduate student training, K-12 teacher trainings on four Schoolyard Ecology protocols, and the Summer Research Program in Ecology for Undergraduates.