Vulnerability of U.S. National Parks to Changes in Climate and Land Use

A. J. Hansen, Montana State University, Bozeman
S. Running, University of Montana, Missoula
C. Davis, Montana State University, Bozeman
J. Haas, University of Montana, Missoula

The U.S. National Park Service faces the challenge of maintaining healthy ecosystems in its parks despite increasingly rapid changes in climate and land use. Using satellite imagery and other datasets, we can produce detailed reconstructions of changes that have taken place in the last few decades and detect how ecosystem processes have responded. These reconstructions show that changes in climate, net primary productivity (a measure of total plant growth), fire risk, and stream flows are very heterogeneous and vary greatly on a fine spatial scale. This complexity makes it difficult to generalize about the changes that take place across large areas, such as national parks.  

The goal of this study is to assess the vulnerability of 70 national parks to land use and climate changes. It includes parks in the U.S. that are relatively large in area (>27,000 hectares, ~67,000 acres) and that represent the full range of regions across the U.S.  

Specific objectives are:

1. Quantify changes from 1900 to present in land use, climate, and biodiversity during 1900–2003 (coarse spatial resolution) and 1982–2003 (fine spatial resolution).  
2. Evaluate the vulnerability of parks to current and near-term future land use and climate based on past ecosystem and biodiversity response to changes.  
3. Evaluate statistical patterns of association between land use, climate, ecosystem function, and biodiversity during this time period as a means of validating vulnerability indices.  
4. Derive guidelines for mitigating the primary vulnerabilities of each park.  

As part of the analysis, our study will determine the boundaries of the ecosystem surrounding each park. Recently, managers have realized the importance of designing parks along ecological boundaries, but in the past many national parks were designed with respect to factors other than ecological completeness, such as scenic value, geological features, or value for human recreation. Thus, many national parks today are only part of larger ecosystems and do not contain all of the resources required to maintain ecological processes. Disturbance regimes, nutrient flows, and animal movements all may operate over a larger area.

The results of this study will suggest which national parks are most vulnerable to climate and land use changes predicted for the next few decades, and they will describe particular threats that park managers may need to address.