Adapting to Climate Change-Driven Loss of Ecologically Important Species and Processes from Park Ecosystems: A Study of Management Options for Glacier National Park Streams in the Context of National Park Service Policy and Guidance—Public Version

Schuurman, Gregor; Lawrence, David

doi:10.36967/2317228

The traditional paradigm in mainstream environmental stewardship assumes a stationary climate in which climatic and ecological change generally occur within bounds (e.g., “natural range of variability”) and managers can conserve ecosystems by preserving their historically co-occurring species, natural communities, and physical and biological processes. For example, 2006 Management Policies, the current NPS management policies document, suggests that by preserving ecosystem components and processes in their natural condition, the NPS will prevent resource degradation and thus avoid any subsequent need for resource restoration. But climate change challenges these long-held assumptions. As local climates become increasingly inhospitable for historically occurring species, managers confront the paradox that maintaining historical (i.e., natural) ecosystem structure and ecological processes may be increasingly difficult with such species. This report examines the NPS policy context for a diversity of potential management responses to this paradox in Glacier National Park, illustrating a type of resource-management challenge that many other parks face. Here, the focus is on a mid- to lower-elevation reach of a lake-connected stream in Glacier National Park that is losing its native top-predator fish species—the bull trout (Salvelinus confluentus)—due to synergistic impacts of (1) climate change (e.g., stream warming and increasingly frequent and long low-flow periods in summer and fall, as well as increasing frequency of rain-on-snow events and associated streambed scour) and (2) the nonnative lake trout (Salvelinus namaycush), which preys on and competes with bull trout. Loss of a top predator in stream ecosystems can cause cascading changes in abundances of other species and in resource flows throughout the aquatic food web and interconnected terrestrial ecosystems. To inform ongoing development of policy and guidance for climate-informed stewardship, this analysis considers potential management strategies developed using the resist–accept–direct (RAD) framework. It considers these strategies against NPS policies to identify where policy is prescriptive, permissive, prohibitory, or unclear, and concludes that current policy—as augmented by the August 2024 Policy Memorandum 24-03 (Managing National Parks in an Era of Climate Change)—recognizes the challenge and instructs managers not to expect park ecosystems to resemble those of the past and to plan and manage for future climatic and associated ecological conditions. Furthermore, NPS policy both expects managers to adapt to climate change “including by proactively resisting, accepting, or directing its impacts” and acknowledges that such actions may entail novel approaches, including substantial interventions or divestment of activities.

Adapting to Climate Change-Driven Loss of Ecologically Important Species and Processes from Park Ecosystems: A Study of Management Options for Glacier National Park Streams in the Context of National Park Service Policy and Guidance—Public Version

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