Creekside Science

Bringing the Bay Checkerspot Back to San Bruno Mountain

In Bay Checkerspot on March 19, 2021 at 10:48 am


Creeksiders and volunteers hunting for caterpillars on Coyote Ridge

Bay checkerspot butterflies were once much more widespread throughout the SF Bay Area. Many factors, including loss of habitat and host plants (Plantago erecta), have contributed to the local extirpation of the species in many sites. Coyote Ridge is the exception, where a large, healthy population can still be found. This spring, Creekside Science estimated nearly 800,000 Bay checkerspot larvae on the the ridge.

San Bruno Mountain is one site where Bay checkerspots were once common, but were then locally extirpated. For the past four years, Creekside Science has been working on bringing this population back. This February/March, armed with a team of volunteers to help collect caterpillars, we brought Bay checkerspot caterpillars from Coyote Ridge to San Bruno Mountain, and dispersed them onto good habitat. The interesting thing about habitat at San Bruno Mountain, though, is that we are seeing the caterpillars happily utilizing a new, much more common host plant, which we believe will increase their chance of persisting on San Bruno. Plantago lanceolata, a weedy invasive plant that is closely related to their host plant seems to also work well as a host plant, so these butterflies will have much more potential habitat than if they relied solely on the dwindled patches of Plantago erecta. This year we translocated 3,859 caterpillars, which we hope will be happy in their new home!

Bay checkerspot caterpillar happily munching on Plantago lanceolata
Bay checkerspot chrysalis

San Francisco Presidio Restoration Monitoring

In Restoration on March 19, 2021 at 9:19 am

Like many military bases, the Presidio of San Francisco had a truly mixed bag of environmental effects on its land when it was an active military base. Military bases often preserve land from development, which is great, but also tend to contaminate soils, and bring in invasive plants both actively and passively. Since the decommissioning of the base, the National Park Service acquired the land. With the help of the Golden Gate National Parks Commission and the Presidio Trust, there has been massive remediation of the land to remove invasive plants, clean soils, and improve the habitat for native plants and animals. They have removed Eucalyptus and Cape Ivy, turned soils over, restored dunes, etc. In one particular spot, the endangered San Francisco Lessingia, which was once nearly extirpated, now thrives on restored dune habitat where a large stand of eucalyptus was removed.    


In the fall of 2020, Creekside Science partnered with the Presidio Trust to monitor vegetation at several of these remediated sites. In most of these sites, we found high native plant cover and great habitat for both these plants and the native fauna. The Presidio is a remaining refuge for plants that were once likely more common before the development of the city of San Francisco. Thus, many of these native plants are rare, and some are even endemic to the Presidio itself. We were grateful to work with the knowledgeable and wonderful employees of the Trust on this important post-remediation monitoring, and learn a few new plants in the process! Thank you to the Presidio Trust for the opportunity, and especially to Esperanza Pimentel, Diony Gamoso, Amy Chong, and Marion Anthonisen, who led us through these amazing Presidio restoration sites!

Creekside Science Tackles Monarch Butterfly Overwintering Habitat Across California

In Monarchs, Research, Restoration, Stewardship on August 23, 2020 at 9:49 am

The Western monarch butterfly population that overwinters in California is in a state of collapse from a panoply of causes, including pesticide use, climate change, land use-change, and deterioration of the overwintering sites along the coast.  Stu has been working with overwintering monarchs since 1990, using hemispherical (fisheye) photography to quantify canopy structure and map wind and sun exposure within the sites.  As of summer 2020, Creekside Science is assessing more than 20 monarch sites from Sonoma to Orange Counties, working with various cities, California State Parks, Resource Conservation Districts, and the Xerces Society to assess the current conditions of groves and to develop long-term management plans.  One fascinating aspect is that conserving monarchs requires thoughtful management of specific non-native eucalyptus forests, which the monarchs have occupied because eucalyptus groves provide the exacting microclimatic conditions sought by the butterflies.

Here is Stu with his venerable fisheye camera rig, while he and Chris were bushwhacking through the dense poison oak understory of a Eucalyptus grove at Andrew Molera State Park in Big Sur.  Stu had worked this site in 2001, and noted densification of the forest that will be captured with the fisheye photos and a novel application of LiDAR (laser mapping from aircraft).

A LiDAR image of Andrew Molera, looking like a 19th Century Japanese woodblock print, provides 3-D structural information.  Note the peaked roof of the Cooper Cabin, built in 1861, and the large trunks of the eucalyptus trees planted around the same time that the cabin was constructed.

Here is a fisheye photo from which canopy openings in different directions can be used to estimate wind and sun penetration.  The cabin is to the upper right, and the Santa Lucia Range can be seen through the large trees surrounding the cabin.