Field Collective

Eco-Patch Test Garden

PROJECT LOCATION: Potrero Hill, San Francisco, CA
SIZE: 900 sq foot (first stage)
PROJECT PARTNERS: Dogpatch & NW Potrero Hill Green Benefit District & Potrero Gateway Park & California Native Plant Society 
PROJECT TYPOLOGY: Biodiversity demonstration garden
ROLE: Project manager, designer and volunteer coordination
STATUS: Installation completed 2020, currently undergoing monitoring

The Potrero Gateway Eco-Patch builds on the work done to establish 17th Street, San Bruno Avenue and Vermont Street as the Potrero Gateway. The Eco-Patch features native San Francisco plants with the intention of providing wildlife habitat and restoring biodiversity in San Francisco. This particular piece of land is situated above serpentine bedrock, which underlies portions of San Francisco (see map below). The selection of plants that survive and thrive in serpentine conditions highlights the natural history of the site and creates habitat for wildlife, such as the Bay Checkerspot Butterfly, which have coevolved with those plants.

This project posits that the Eco-Patch can grow into a demonstration garden to serve as a resource for the greater community that showcases the ecological and aesthetic benefits of habitat restoration. By design, the Eco-Patch encourages imitation, as it seeks to show the positive impact that a network of habitat patches can have on biodiversity. Geographic isolation caused by habitat fragmentation is one of the leading causes of biodiversity loss and so a network of patches in close proximity helps remedy this.

In San Francisco there is already a precedent for habitat corridors composed of patches that create stepping stones for wildlife. In particular, the project is inspired by the success of the Green Hairstreak Butterfly Corridor led by Nature in the City. Currently, the habitat corridors needed to get rare and endangered wildlife that depend on serpentine adapted plants from their current locations to the Potrero Eco-Patch do not exist. However, if enough patches are planted, wildlife can access the Eco-Patch and beyond.

TEST PATCH
The first stage of the Eco-Patch is a 900 square foot test patch that includes a select number of plants from our proposed list. Monitoring of the test patch will determine the site suitability of specific plants and the success of different weed management strategies. Installation, maintenance, and monitoring of the test patch is a volunteer effort with funding for material costs from the Dogpatch & NW Potrero Green Benefit District. The test patch is adjacent an existing Coast Live Oak that serves as a keystone species. Plant selection is based on the criteria of being native to San Francisco, and of having high habitat value. Additional considerations include being low-water use, wind tolerant, and adapted to or tolerant of serpentine soils. Eight combinations of plants will be tested to ensure dynamic seasonal changes and aesthetic harmony. Each combination of plants is then divided into three different management zones to test alternative management approaches to removing existing vegetation and weed removal. The knowledge and experience gained in the test patch, including cost, time and labor will inform the management approach for the full Eco-Patch project.

Map of serpentinite within San Francisco. The current fragmented native patch network. A connected native patch network, achieved through the community planting native habitat in their own backyards.

PHOTO CREDITS: 1. ©2019 Zoya Akulova – CalPhotos, used under CC BY-NC 3.0* / Cropped from original, 5. © eddie@naturetrip.com    |     CalPhotos. 2020. Regents of the University of California, Berkeley. Accessed on December, 19, 2020. Available online at: http://calphotos.berkeley.edu/     |   *To view a copy of the license, visit www.creativecommons.org/licenses/by-nc/3.0/

An Eco-Patch volunteer sheet mulching. We are testing three different weed management strategies at the Eco-Patch Test Garden: 1) Sheet mulching; 2) Sheet mulching + filler species; 3) Solarization. Photo credit: Scott Cole

PHOTO CREDITS: 1. ©2007 Matt Lavin – Wikipedia, used under CC BY-SA 2.0*** / Cropped from original; 2. Image by Stanley Spencer; 3. ©2011 Barry Breckling – CalPhotos, used under CC BY-NC-SA 3.0* / Cropped from original; 5. ©Noreen Weeden; 6. © 2020 Terri McFarland Landscape Architecture (TMLA); 7. ©2011 Eric Wrubel/NPS – CalPhotos, used under CC BY-NC 3.0** / Cropped from original; 8. ©2005 Steve Matson – CalPhotos, used under CC BY-NC 3.0** / Cropped from original; 9. © eddie@naturetrip.com; 10. © 2020 Terri McFarland Landscape Architecture (TMLA); 11. ©2020 Barry Breckling – CalPhotos, used under CC BY-NC-SA 3.0* / Cropped from original; 12. ©2020 Jean Pawek – CalPhotos, used under CC BY 3.0**** / Cropped from original CalPhotos. 2020.    |    Regents of the University of California, Berkeley. Accessed on December, 19, 2020. Available online at: http://calphotos.berkeley.edu/     |    *To view a copy of the license, visit www.creativecommons.org/licenses/by-nc-sa/3.0/ **To view a copy of the license, visit www.creativecommons.org/licenses/by-nc/3.0/ ***To view a copy of the license, visit www.creativecommons.org/licenses/by-sa/2.0/dee ****To view a copy of the license, visit www.creativecommons.org/licenses/by/3.0/

Eco-Patch Test Garden plant procurement – Ecotype locations and quantities secured.    |   Using local ecotypes (plants of known genetic origin) was important for our project partners, the California Native Plant Society. Using local ecotypes aids in sustaining local genetic diversity and takes advantage of a plant’s evolutionary adaptations to local conditions.

The test garden layout – eight different plant mixes to be tested, each trialed with a different weed management strategy.

We are inviting the community to join us in the process of monitoring and observation through the citizen science app, iNaturalist. Through data collected on iNaturalist, we can monitor the presence of wildlife and plant phenology within a quarter mile of the site. This diagram shows how you can view recent observations within the Eco-Patch monitoring area using the iNaturalist interface.
Photo credit: eddie@naturetrip.com
iNaturalist: https://www.inaturalist.org/projects/potrero-eco-patch-monitoring-area

Additional signage designed by neighbor, artist, and Eco-Patch volunteer Michael Kerbow. Photo credit: Jean Bogiages