August 25, 2016 marks the 100 year anniversary of the National Park Service. Climate change is one of the biggest challenges facing parks today, and understanding its implications will be critical for effective park management into the future. As part of an effort to highlight research completed by the DOI Climate Science Centers in national parks, we are featuring the results of an assessment of  the exposure of national parks to climate and land use change, published in 2014. This research was funded in part by the North Central Climate Science Center.

Based on current climate change projections, it’s estimated that only 8% of protected areas worldwide will maintain their current average temperatures over the next century. Protected areas such as national parks are set aside specifically for the purpose of protecting biodiversity from the threats posed by human activities. It’s becoming increasingly clear, however, that changes occurring beyond park boundaries both regionally (such as land use change) and globally (such as climate change), are threatening protected areas.

The term ‘protected area-centered ecosystem’ (PACE) was coined to describe areas where human activities can negatively affect protected areas (see Diagram). For example, land use intensification in areas surrounding protected areas, such as increased housing density, can disrupt ecological processes and biodiversity within protected areas. Therefore, in order to develop effective management strategies for parks, managers may need to consider activities occurring beyond the park—such as infrastructure development and sources of pollution, like industry and agriculture. 

A study published in 2014 explored past and expected future conditions in PACEs surrounding U.S. national parks to better understand their exposure to the threats of climate and land use change. The publication provides important information that can help park managers adapt to changing conditions and ensure the protection of species and their habitat.

Using the boundaries of 49 PACEs delineated around 57 national parks, monuments, and recreation areas (collectively referred to as ‘parks’), researchers (1) identified the exposure of these areas to land use change, climate change, and invasive species over the past 100 years, and (2) projected their future exposure to land use and climate change over the next 100 years. 

Results: Historic Exposure (1900-2010)

1. Housing density increased on average by 741% in PACEs, from 1940-2000.
2. On average, 13.6% of plant flora found within parks was nonnative. Parks with fewer nonnatives were located in the Southwest, while parks with higher percentages of nonnatives were found in Florida and California.
3. PACEs warmed by an average of 1°C over the past century. The highest rates of warming occurred in the Southern Rockies and Colorado plateau region. Some parks, particularly those in the eastern U.S., did not experience any significant warming.
4. Precipitation increased significantly in 22% of PACEs, most of which were located in the Midwest.

Results: Future Exposure (2000-2100)

1. Housing density is projected to increase on average by 42% by 2030, 125% by 2060, and 255% by 2090. On average, projected increases in housing density are 82% of the past rate. PACEs in the Southwest are expected to experience particularly high increases.
2. PACEs are projected to warm by 0.9°–2.4°C by 2030, and by 2.5°–4.5°C by 2090. Those located in the southwest deserts and western mountains have the highest projected warming.
3. Average annual precipitation is projected to increase in all but four PACEs by 2030, particularly in the eastern and upper Midwestern regions. By 2090, precipitation is expected to decrease in 13 PACEs, particularly in the southwestern deserts. Precipitation will increase in the remaining PACEs.
4. On average, 30% of the area within PACEs is projected to experience changes in climate that are unsuitable for current vegetation and species composition by 2030. This proportion increases to 40% by 2090. Parks in the Southwest and Rocky Mountains, such as Yellowstone, Glacier, and Petrified Forest national parks, are projected to have significantly higher than average proportions of unsuitable area (up to 96%).

This study informs our understanding of the changes expected to take place within and outside park boundaries, and the extent to which these changes differ from past conditions. There is a wide variation in past and future exposure to climate and land use change, and some parks will pose a greater management challenge than others.

Effective stewardship of national parks into the future will require managers to continually adapt to evolving conditions, and management strategies will differ from park to park. Not only does this study provide an overview of the change that has and potentially will occur in parks across the country, but the results can also be used by park managers at a local level to tailor park-specific adaptation strategies.

Read the full paper here and learn more about the associated North Central CSC project here.