The Presidio is a beautiful natural habitat that promotes native wildlife and plants. Although it is now a blossoming ecosystem that is flourishing, it has not always been this way! 

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It was during my Ecology lab last year on a hike through the Tennessee Hollow trail that I learned about the history of this now nature preserve. I was personally very inspired by the conservation efforts done to this area despite its past.  The Presidio’s official website provides the following summary of the Presidio’s history. Originally, the Presidio was territory to the Yelamu, a local tribe of the Ramaytush Ohlone peoples, for thousands of years. In the year that the United States was founded, Spain built a military fort on this land. After gaining its independence, Mexico operated the fort until the United States won the Mexican-American war, and the U.S. Army took the fort over. Image 2 shows what this base used to look like.

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The Tennessee Hollow watershed and Crissy Field were then used as landfills for the U.S. Army. A few decades after this, Congress created the Golden Gate National Recreation Area (GGNRA), a new national park under the National Park Service. There was a law when the GGNRA was created that stated if the Army were ever to leave, then the land would become a part of the national park as well—and just that happened. There were then problems transitioning the Presidio as it needed lots of cleanup. However, Representative Nancy Pelosi led a bipartisan effort to save the space as a public park. It is now managed by the Presidio Trust thanks to their work. 

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Its use as a military base and a trash dump caused a lot of harm to the Presidio. There needed to be a full restoration effort in order to bring back the natural ecosystem that was destroyed. The landfill had to be dug up as it filled up the Tennessee Hollow watershed, and the trash was removed as part of a massive project to clean up the environment. Once dug up, the water that once ran below ground was daylighted. According to this article by Princeton Hydro, daylighting water sources is important as it promotes biodiversity, mitigates flooding, improves water quality, and more. The daylighted stream can be seen in Image 3.

On one of the information signs along the hike, I learned that currently the water source is only partially daylighted, but there are plans to get all of Tennessee Hollow daylighted. The practice of bringing water to the surface is common in the work of restoring natural areas. It allows for the wildlife and plants to access this water source. The water flows from the underground water transportation next to the Presidio Golf Course down to the bay. The Tennessee Hollow watershed is also a freshwater source for Crissy Marsh. The water running into the bay is another important impact of this clean up! This landfill runoff was contaminating the bay prior. And now with the Presidio Golf Course being upstream, there needs to be efforts gone into making sure that fertilizer runoff and other pollutants don’t enter the bay as well. This is why it is important for the willow trees growing along the daylighted stream to be there. The roots of the willows work to clean the water before it enters the bay. Their roots pick up contaminating particles before they get too far down the Presidio’s riparian zone. A riparian zone is the land that meets a water source. It is a very important part of this ecosystem as it provides an important habitat for birds and frogs in the area.

The main portion of the restoration work was done by the community, park volunteers, and partners. It is big thanks to this community that made the Presidio into a place of such change and environmental victory. There are still clean ups in the Presidio if you ever want to volunteer. You must register with the Presidio Habitat Stewardship every Saturday and on the first and third Wednesdays of every month, both from 9:00 a.m.–noon. This volunteer work allows the park to continue to thrive.

If you visit the Presidio now, there are beautiful displays of native plants on the hillsides, a small section below Inspiration Point with redwood trees, a clean watershed that works to keep the San Francisco Bay unpolluted, a rich diversity of bird species for birdwatching, views from the Palace of Fine Arts to Alcatraz, and a selection of beautiful hiking trails that wind through the park. The Presidio Nature Snapshot reveals that there are now 323+ bird species, 300+ native plant species, 12 native plant communities, five endangered species, 82 butterfly and moth species, 21 land mammal species, five reptilian species, and four amphibian species. You can really feel the vast biodiversity as you walk around this park. 

When walking through the trail to capture all the photos included in this post, I was transported into the magic of the Presidio once more. There are many signs along the trail where you can stop and learn about its history. A trip to the Presidio can even be interactive! In between the willow trees of the riparian zone lives a field station, seen below, with free adventure map guides of the Presidio as well as bird, plant, wildlife, and bug identification sheets. There are songbirds singing all along the hike. Many friendly residents of the area regularly walk their dogs or jog. I even stumbled upon a community garden in the neighborhood with tomatoes, kale, peppers, flowers, zucchini, and more! It is always a beautiful, welcoming escape into nature every time I visit.

I recommend everyone who lives in the city go to this area. It really goes to show how effective conservation can become and how important it is to continue to save the failing ecosystems of this world. I recommend walking the Tennessee Hollow trail, Ecology trail, and Lover’s Lane. I hope you are able to find your way to experience what the Presidio has to offer!

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