Drivers of Ecosystem Recovery on Santa Rosa Island

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The Channel Islands were used as ranches for almost 150 years. Sheep, cattle, pigs and other livestock grazed on native perennial scrub, leaving behind barren landscapes that could not collect moisture from coastal fog. In time, ranching ended and livestock were removed. WERC’s Dr. Kathryn McEachern is monitoring habitat recovery and testing the efficacy of restoration practices on the islands for the National Park Service.

Screenshot of moisture condensing on tree branches
(Public domain.) Screenshot from the video "Harnessing Fog on Santa Rosa Island" of fog moisture condensing on a tree branch. Video shot by Susan Bloom, CAiMedia.

Monitoring and Modeling Fog Drip Patterns on Santa Rosa Island

Fog plays an important role across the islands of Channel Islands National Park. Its moisture contributes just as much, if not more, water to the environment as rainfall. This water is especially important for keeping native vegetation alive from May through September, during California’s summer drought.

The National Park Service is currently restoring ecosystems damaged by ranching livestock on Santa Rosa Island, the second largest of the northern Channel Islands, and has asked Dr. McEachern to identify areas on the island with reliable fog. Using rain gauges, Dr. McEachern and collaborators have established “fog weather stations” across the island to measure the amount of fog moisture dripping from trees and artificial structures set up by their team. Together wtih a team lead by the University of Oregon lab of Dr. Chris Still, McEachern has also used satellite data to develop fog inundation models for the northern islands. Her studies will help the National Park Service understand how water contributes to Santa Rosa ecosystems, how fog varies seasonally and geographically, and provide the Service with guidance on how to “jump start” the ecosystems’ recovery using this natural part of the environment.


Restoring Santa Rosa Island Cloud Forests, Rare Plants, and Watersheds

A forest of sturdy oaks and pines once thrived in the heart of Santa Rosa Island. Nicknamed the “cloud forest,” these trees drank from the heavy fog that rolled over Santa Rosa’s upland ridges, and dropped their seeds under chaparral shrubs that sheltered new plants from the wind and sun. However, more than a century of ranching on the island stripped Santa Rosa of its upland shrubs. Today, Santa Rosa’s cloud forest struggles to recover in dry, eroding soils without the shrubs that once collected water from the fog.

At the request of the National Park Service, Dr. McEachern and colleagues are working on a four-year cloud forest recovery research project that uses artificial structures to slow erosion, capture fog, increase soil moisture and establish plants from nursery-grown stock and seeds. The project’s long-term goals are to create self-sustaining stands of trees and shrubs that can re-start the upland hydrologic cycle, and demonstrate the local effects of fog on plant growth, soil moisture, erosion rates, sustainability and ecological complexity.

View local news on this project (source: The Ventura County Star).

Video Transcript
The familiar marine fog of Southern California’s coasts evokes more than just beauty and emotion — it also brings life. At the remote and hauntingly gorgeous Channel Islands National Park off the coast of Los Angeles, USGS scientists are helping the National Park Service understand how the loss of native plants has changed the natural water cycle of these islands. Scientists are studying how these plants capture life-giving water from the daily fog to quench these isolated landscapes. The research is helping park managers restore native plants after decades of human impact, in hopes to bring life-giving moisture back to this National Park. Kathryn McEachern, U.S. Geological Survey (Public domain.)