For more than 100 years, the Unite States National Park Service (NPS) has been guided by a mandate to preserve parks and their resources for the enjoyment of present and future generations. But all parks are subject to conditions that may frustrate preservation efforts. Climate change is melting the glaciers. Rising seas are sweeping away protected shorelines. Development projects, accompanied by air, water, light, and noise pollution, edge closer to parks and fragment habitats. The number of visitors and vested interests are swelling and diversifying. Resources for preservation, such as funds and staff, seem to be continuously shrinking, at least relative to demand.

Still, the NPS remains committed to the preservation of our natural and cultural heritage. Yet the practice of that promise is evolving, slowly and iteratively, but detectably. Through explorations of legal and scholarly literature, as well as interviews across the government, non-profit, and academic sectors, I’ve tracked the evolution of preservation in parks. How is preservation shifting to address socio-ecological change? How has preservation evolved before? How should the NPS preserve parks moving forward?

The practice of preservation has come to rely on science, including partnerships with academic researchers, as well as inventory and monitoring programs. That shift has in part been guided by goals that have also become more informed by science, like ecological integrity. While some interviewees see science as a solution to the NPS’s challenges, others wonder how applying science can get “gnarly,” due to uncertainty, lack of clear policies, and the diversity of parks and resources. “Gnarly” questions stem in part from the complexity of the NPS as a socio-ecological system, as well as from disputed, normative concepts that underpin the broader philosophy of preservation, including naturalness. What’s natural in the context of pervasive anthropogenic change? Further, I describe how parks hold deep, sometimes conflicting, cultural and symbolic significance for their local and historical communities and for our nation. Understanding and considering those values is part of the gnarly task park managers face in their mission to preserve parks. I explain why this type of conceptual and values-based uncertainty cannot be reduced through science.