Prescient thinking and the future of ecosystem services in New England
The nature and extent of land-use and land-cover change (LULCC) in New England is influenced by large-scale economic, social, and policy conditions which are difficult to predict but that can be bracketed by scenarios describing a range of plausible future land-use conditions. Through engagement of key decision makers from state and federal agencies, and representatives from conservation organizations, academic institutions, and landowner organizations we develop a set of scenarios of future land use in Massachusetts over 50 years (2005-2055) varying from a “free market future” – with large and unregulated forest conversion - to a green future – with extensive conservation easements and clustered forest conversion. These scenarios are then used to parameterize a coupled forest succession and land use change model (PnET/Landis II) with established IPCC climate change projections to estimate landscapes at a high spatial (50m) and temporal (5yr) resolution. Modeled landscapes are used to address the principal research question of: how do projected changes alter a broad suite of ecosystem services at the scale of the state, and for individual towns and watersheds, including carbon storage, water regulation, nutrient retention, and ecosystem fragmentation and degradation, employing both analysis of Landis outputs and the InVEST approach.
Results highlight the variability of future landscape changes, with simple extrapolation of current trends resulting in an increase in aboveground biomass (AGB) from ~125 to 150 Tg, primarily related to extensive carbon sequestration by aging secondary forests currently dominating the landscape. The conversion of forest to crops and pasture within the “regional self-sufficiency scenario”, however, results in a reduction of AGB from ~125 to ~120 Tg. Forest degradation – using year 2005 forests as a baseline – increases up to 250% in some scenarios over the study period. Dramatic increases in water yield are also observed across all scenarios as forest conversion alters the balance of evapotranspiration and precipitation, and climate change results in large increases in precipitation. This study both develops a novel framework for integrating and quantifying future changes in ecosystem services from coupled land use and climate change, and applies them to a study area at a pivotal transition between different future trajectories. The implications and utility of this approach to other landscapes are also discussed.