COS 21-1 - How do we decide when to resist, accept, or direct climate-driven changes in ecosystems? A case study from Acadia National Park

Abstract: Ecologists and managers are having to make decisions about how to adjust management practices in response to climate-driven changes. Unfortunately, while the scientific literature thoroughly describes ways that climate change threatens ecosystems and protected areas, there are few published examples of how managers are responding to these threats and what they are learning. The National Park Service has adopted a resist-accept-direct framework to help guide management decisions in light of climate change. The framework asks ecologists and managers to consider when it is most appropriate to resist changes and preserve current or past conditions, when it is appropriate to accept changes as they occur, and when it is best to direct changes toward states that ecosystems might not achieve without active management. This presentation will describe how ecologists and managers are applying this framework in the restoration of Great Meadow, a large freshwater wetland in Acadia National Park, and what they are learning during the early stages of restoration. The health of Great Meadow has been degraded by non-native invasive shrubs, historic trails and ditches constructed in the wetland, and an undersized culvert at the outlet of the wetland, which exacerbates flooding during extreme rainfall events. The restoration project aims to restore natural hydrology and native plant species and aims to improve recreational opportunities around the wetland. Park staff and partners are taking an experimental approach to the restoration, and are testing a mix of resist, accept, and direct approaches. Specifically, managers are removing invasive plants (a resist strategy) to buy time to restore native plants. Managers are improving culverts and plugging ditches (accept strategies) to better accommodate extreme rainfalls, which are becoming more frequent. And managers are testing how well native plants sourced from locations south of Acadia perform relative to local plants (a direct strategy) at surviving, growing, and suppressing reinvasion by nonnative species. Early lessons suggest that large-scale management of hydrology and planting of native plants is necessary to achieve the management goals. Small-scale adjustments to hydrology, removing invasive plants, and allowing native plants to recolonize on their own is not adequate. An experimental approach is critical, given uncertainties of future conditions. And effective communication is necessary to bring along public support as management approaches change.