What happens to U.S. landscape when protected areas vanish?

© Yang Song

Editor’s note: Following an unprecedented four-month review period of 27 of America’s national monuments, Interior Secretary Ryan Zinke in September made two significant recommendations to U.S. President Trump: Change some boundaries and open the door to drilling and mining. New research shows, however, that boundary changes and other alterations to protected lands leave a lasting legacy on the land — and it’s not always good. Ph.D. candidate and Conservation International (CI) grantee Rachel Golden Kroner explains to Human Nature how the histories of places like Yosemite National Park show us the implications of relaxing restrictions within America’s protected lands —even 100 years later.

Question: Walk us through your research on Yosemite National Park.

Answer: Yosemite National Park has quite a dynamic past, as I’ve discovered through my research on PADDD (protected area downgrading, downsizing and degazettement) with Mike Mascia, CI’s senior director of social science. Yosemite was established as a land grant in 1864 and officially as a national park in 1890. Several years later, it started to experience legal changes that affected its status and size. In 1905 and 1906, it was reduced in size by nearly one-third, and soon after in 1913, the O’Shaunessy dam was built in Hetch Hetchy Valley.

I examined the fate of the lands that were removed from Yosemite in 1905 and 1906 to allow forestry and mining activities. How do they look today? Is there any difference between the places that were removed from protection and those that remain protected, or were re-protected later as wilderness areas? We looked at forest fragmentation by roads as an indicator. The more fragmentation there is, the more disconnected the landscape is, making it harder for species to migrate between these separate pieces of land. Fragmentation can also reduce certain species’ diversity and population sizes and leads to “edge effects,” which can result in an increased fire risk and reduce the quality of the habitat. Our results show that there is a big difference between lands that were removed from protection and those that remain unprotected today — unprotected lands are more highly fragmented by roads compared to lands that were re-protected or have remained protected within the boundaries of Yosemite the entire time.

Q: What are some of the lasting impacts of these PADDD events in Yosemite?

A: If some modification to the land was not previously allowed, and a new legal change had to be passed to allow this new use — for example, if mining or drilling is newly authorized inside a national monument— that’s a PADDD event.

In Yosemite, originally the area had connected forests. More intact, larger forests support higher species diversity that helps keep the entire forest ecosystem healthy. Once the dam was built in 1913, suddenly a reservoir was created at a site that was once contiguous forest, which dramatically altered the landscape and local hydrology, affecting aquatic communities. The dam also provided a water source for San Francisco, so it was politically desirable to make this tradeoff between preservation and development. Infrastructure is good for communities up to a point, depending on the scenario; it comes down to a decision of where we should avoid installing new infrastructure because a place is particularly valuable for biodiversity or for providing other services such as clean air, water, and climate regulation that would be degraded by new infrastructure.

Q: How could PADDD events in the United States, such as national monument downsizing, impact both the U.S. and other countries?

A: The U.S. is seen as a leader in conservation — our national parks were the first of their kind in the world. Places like Yellowstone, Yosemite and Grand Canyon national parks are the crown jewels of our country. Other countries, including China, are using the U.S. National Park Service as a model to enhance their conservation programs. While national monuments are in a different category than national parks, they both have the same bedrock values: protect special places for now and for future generations.

One of the best predictors of the future is the past, so looking at PADDD events that shaped Yosemite can help us understand what might happen with similar PADDD events — even though places like Bears Ears and Papahānaumokuākea national monuments protect vastly different resources and have their own unique histories. The choices that we as a society make in terms of how we manage our land and what we decide to protect have enduring impacts. Land set aside in Yosemite that has remained protected for over a century has successfully maintained its ecological connectivity and will continue to do so as long as it stays protected and well-managed.

Protection isn’t the end of the story; good management is key for these places to continue to preserve habitat as well as cultural, economic and ecological benefits to people. We see that the reverse is true as well: The implications today of choices to adjust the rules or reduce the boundaries of national monuments may have lasting consequences.

Rachel Golden Kroner is a Ph.D. candidate and Conservation International grantee. Sophie Bertazzo is a senior editor at Conservation International.

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