September 1, 2019.
Santa Rosa Island, Channel Islands National Park, was grazed by cattle, sheep, pigs, elk, and deer for 154 years, degrading the island’s vegetation and causing erosion. In 1998, the livestock were removed, and in 2011 the remaining big game animals were removed, allowing ecosystem recovery to begin. This study evaluated growth of two native species planted in 2016, at the cloud forest restoration site on the Soledad Ridge. Baccharis pilularis (coyote brush) was planted as nursery stock from 2-inch pots, while Quercus pacifica (island scrub oak) was planted as sprouted acorns. The plants were watered with drip irrigation 2016-2018, and some had “fog fences” of galvanized 1-inch wire covered with 40% shade cloth installed to intercept blowing fog and deposit it as fog drip along the planting line. The restoration area had three sites with different substrate types: Site 1 consisted of soil, Site 2 was bedrock, and Site 3 had bedrock covered by 1-2 cm of silt. In 2019, we inventoried species present, species height and canopy area. The purpose was to evaluate if the plants planted near a fog fence were larger in height and canopy area than those planted without a fog fence. Plants growing with fog fences were only found larger than those without when observing all the sites together for Baccharis pilularis (p=0.000 for average height; p=0.001 for average canopy area) and were not found larger when observing all the sites together for Quercus pacifica (p=0.289 for average height; p=0.083 for average canopy area). However, all three sites had different substrate types so the data was analyzed for the individual sites as well. The study shows that there are significant differences in height between plants planted with fog fences versus plants planted with no fences, but that the differences vary across different substrate types.
Botany | Plant Biology
California State University, Channel Islands (CSUCI)
Thank you to Marisol Villarreal, Stephen Bednar, Dulce Lopez, Lauren Smith, Emma Akmakdjian, Russell Bradley, Robyn Shea, and Aspen Coty. The 2019 STEM Teacher and Researcher Program and this project have been made possible through support from Chevron (www.chevron.com), the National Marine Sanctuary Foundation (www.marinesanctuary.org), the California State University Office of the Chancellor, and California Polytechnic State University SLO in partnership with the Santa Rosa Island Research Station at CSU Channel Islands, U.S. Geological Survey, Channel Islands National Park, and Mountains Restoration Trust. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funders.