Comparison of an Endangered Species’ Seed Bank Before and After Ungulate Removal

The purpose of this study was to assess the impact of the removal of ungulates on the soil seed bank of the endemic Santa Rosa Island manzanita (Arctostaphylos confertiflora). A. confertiflora was trampled and browsed by non-native ungulates between the years 1850 and 2011 which reduced its ability to produce seeds.This species is an obligate seeder, meaning that sprouting from seeds in the soil is its only method of reproduction. Due in part to the lack of its soil seed bank, this species was federally listed as endangered by the US Fish and Wildlife Service in 1997. In order to assess the trend in its seed bank density, researchers compared its density in 2004 to its density in 2018. There are three stands of of A. confertiflora on the island, and this study collected data on the seed banks in each location. The overall methodology for surveying the seed bank was by selecting sixteen random plants in each stand and collecting 12 soil samples under the canopy of each one, which were sieved to count the number of seeds. The number of seeds was extrapolated to determine the number of seeds per square meter (seeds/m2) of soil surface sampled. The data set examined for this poster focuses on only one of the three stands; data on the other two stands have yet to be examined. This pilot data set found a 213% increase in number of seeds/m2 in the stand from 2004 to 2018, although results were not statistically significant at the 95% confidence level (Mann-Whitney U=. A Mann-Whitney U test found that the 2018 seed bank at Telephone Road did not have a significantly higher number of seeds than the 2004 seed bank (U=88.5, p=0.13). These data can be used by agency scientists to evaluate status and plan further management for A. confertiflora conservation and recovery

Cultural Border Crossing: An Exploration of Power, Positionality, and Pedagogy in Context

This paper explores literature drawn from interdisciplinary scholarship that speaks to positionality as it applies to the complex dynamics of intercultural border crossing through the lens of two distinctly different institutional contexts – an adult service learning partnership at a private, Northeastern college and an indigenous adult cohort university program

Effects of Habitat Restoration on Santa Rosa Island’s Soil Retention

Ranching began on Santa Rosa Island in the 1840’s, consequently introducing nonnative megafauna that put novel selective grazing pressures on endemic plant species. Their movement patterns also altered substrate integrity as the land became denuded of any stabilizing vegetation. Dense groves of island oak (Q. tomentella) are known to aid in sediment deposition and retention. The groves also function to collect water during periods of intense fog common to the island. This experiment sought to determine whether sediment is being lost or deposited on a ridge in the middle of the island containing a grove of Q. tomentella. The slope was divided into three sections based on vegetation, severity of slope, and substrate type. Three transects were installed in each section. Each of the nine transects where 60 meters long and composed of nails that were a uniform 15 cm above the surface, installed in January 2016. The results show all three sites experienced soil deposition, but the three sites were not significantly different from one another. Three transect lines intersected with erosion control structures. In those locations, nails were additionally installed upslope and downslope of the structure to determine if there were differences between the two locations relative to the erosion control structure. The results show areas upslope of these structures experience more soil deposition than areas downslope. This data informs future restoration attempts in their decision for placement of erosion control structures. Future studies could focus on areas of the slope would benefit most from fog collecting devices, as lack of water on the slope is a factor currently preventing the colonization of many plant species

Soil Moisture on Soledad Ridge in Santa Rosa Island, Channel Islands National Park

Santa Rosa Island is one of the Channel Islands off the coast of southern California. Before the island was heavily grazed, Santa Rosa Island is thought to have had large stands of island oak trees, Quercus tomentella, that provided a critical source of water for the ecosystem by creating a “cloud forest”. Wind-borne fog collects on the leaves, branches, and twigs of the island oaks and other native shrubs. Once the water condenses it drips, falls, and soaks into the soil. Introducing cattle and especially sheep to the island has damaged the ecosystem and nearly decimated Santa Rosa Island of its native oaks and woodland plants. The Cloud Forest Restoration project aims to restore native trees and other plants to the central high ridge. Fog panels covered in mesh have been installed in areas on the ridge to collect fog and drip water down into the soil. In my study, soil moisture data was collected at areas 5 centimeters down slope from fog fences and above wattles (coconut fiber rolls used to prevent erosion of the slope). A second set of data was collected at areas with wattles only. Soil moisture readings were taken at 5 and 10 centimeters depths. The data suggests that the soil at fog fences is moister at both depths of 5 and 10 centimeters than at areas with wattles only. In addition, the soil was moister at 10 centimeters than 5 centimeters at sites with fog fences, suggesting substantial subsurface infiltration. This has implications for future planting projects because the extra fog drip provided by the panels does seem to be a significant source of moisture for new transplants

Monitoring Fog Potential on Santa Rosa Island

Fog moisture on Santa Rosa Island plays an integral role in its ecosystems. It is important to understand how fog patterns could potentially effect the flora and fauna. I hypothesized that north facing side of the ridge will have more potential fog moisture due to the predominant wind direction coming from the north. This study used Fog capturing Screens to determine relative amount of fog on the north and south sides of the main ridge of the island. Three locations along the ridge had two Fog Screens placed on the north and south side of the ridge at similar elevations. Fog Screens are 12 gauge 1” by 1” wire mesh fencing with 40% shade cloth attached to the mesh fencing. Each Fog Screen is 1 meter long by 0.5 meter high supported a wooden and metal structure. The amount of moisture collected by a Fog Screen was recorded by a HOBO Rain Gauge Data Logger #RG3-M. I found that more moisture was collected on the north facing slopes of the ridge compared to the south facing slopes, supporting my hypothesis. With more moisture on the north facing slope, there is more potential to see wetter local conditions for plants and animals

Impacts of Fog Drip on Survivorship and Growth of Native Herb and Shrub Seedlings on Santa Rosa Island

Overgrazing on Santa Rosa Island led to loss of topsoil in ridgeline groves of endemic island oaks (Quercus tomentella). Restoration specialists attempting to mitigate the impacts of wind and water erosion must determine efficient methods of reestablishing native vegetation. Planting pillows, burlap sacks filled with planting mix and attached to the bedrock substrate, may nurture seedlings long enough for their roots to penetrate the underlying sandstone. Since the island’s ridgeline habitat is often inaccessible during the rainy season, restoration efforts are largely confined to the dry summer months, during which condensed fog is an important source of moisture for plants. This study examined the performance of native seedlings in planting pillows under different conditions. Groups of seedlings including coyote brush (Baccharis pilularis), purple needle grass (Stipa pulchra), and yarrow (Achillea millefolium) were planted into each pillow, along with pretreated seeds of island ceanothus (Ceanothus arboreus). Seedling growth and survivorship was compared between pillows placed in the dripline of existing oak canopy, pillows fitted with fog capture structures, and pillows lacking any specific fog capture mechanism. Over a five week period, dripline seedlings demonstrated the highest growth and survivorship, seedlings planted with fog capture structures demonstrated intermediate success, and seedlings without the support of any fog capture source were the least successful

Effects of Habitat Restoration on Soil Retention on Santa Rosa Island

Ranching began on Santa Rosa Island in the 1840’s, consequently introducing nonnative megafauna that put novel selective grazing pressures on endemic plant species. Their movement patterns also altered substrate integrity as the land became denuded of any stabilizing vegetation. Dense groves of island oak (Q. tomentella) are known to aid in sediment deposition and retention. The groves also function to collect water during periods of intense fog common to the island. This experiment sought to determine whether sediment is being lost or deposited on a ridge in the middle of the island containing a grove of Q. tomentella. The slope was divided into three sections based on vegetation, severity of slope, and substrate type. Three transects were installed in each section. Each of the nine transects where 60 meters long and composed of nails that were a uniform 15 cm above the surface, installed in January 2016. The results show all three sites experienced soil deposition, but the three sites were not significantly different from one another. Three transect lines intersected with erosion control structures. In those locations, nails were additionally installed upslope and downslope of the structure to determine if there were differences between the two locations relative to the erosion control structure. The results show areas upslope of these structures experience more soil deposition than areas downslope. This data informs future restoration attempts in their decision for placement of erosion control structures. Future studies could focus on areas of the slope would benefit most from fog collecting devices, as lack of water on the slope is a factor currently preventing the colonization of many plant species

Irrigation Efficiency of Santa Rosa Island Cloud Forest Restoration Project

Beginning in the 1800s, sheep and cattle ranching have caused significant erosion and devegetation of Santa Rosa Island, Channel Islands National Park. In an effort to contain what little soil is left and rebuild the native chaparral, the Cloud Forest Restoration Project is testing erosion control structures such as wattles, leaf litter fences and silt dams. This summer a drip irrigation system was installed along with fog capturing fences to supply water to native plants transplanted near the erosion control structures. As the project has grown, more irrigation has been added to increase the area available for transplanting. This irrigation system varies in elevation, slope, and diameter and lengths of irrigation lines. Because this project is experimentally monitored, it is important that all the transplants obtain the same amount of water. To check the efficiency of this system, the flow rates of 1.9L/hr rated pressure-compensating emitters along ¾” diameter polyethylene irrigation tubing were checked. Flow rates were relatively consistent at 1.53 L/hr, 1.60 L/hr and 1.59 L/hr for 1/3, 2/3 and the whole system turned on, respectively. Although one might expect the addition of more irrigation line and emitters to decrease water pressure and thus the flow rate of individual emitters, the flow rates of emitters were found to be unaffected, indicating the effectiveness of the pressure-compensation. However, the flow rates of emitters were consistently lower than their 1.9 L/hr rating. In conclusion, the irrigation system is currently providing equal water to each of the transplants, but at a rate lower than expected

Santa Rosa Island Restoration Study: Fog Fences vs. No Fences

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

Understanding Soil Moisture Levels on Soledad Ridge, Santa Rosa Island, California during the Summer Months

Santa Rosa Island located off the coast of Santa Barbara County was grazed by non-native ungulates leaving the island stripped of vegetation topsoil layer. With the removal of ungulates, the National Park Service began restoring the Cloud Forest on Soledad Ridge. Soledad Ridge is said to have once been covered by large stands of island oaks (Quercus tometella) and other endemic and native plants. The unique leaf and structural morphology of such vegetation collects water from wind derived fog which serves as the main source of water for this unique ecosystem. In an effort to jump-start ecosystem vegetation recovery, a total of 12 two by ten-meter restoration plots under three restoration treatments were installed across four sites. Two sites are characterized as soil sites and two are characterized as bedrock sites. The restoration techniques and treatments include the installation of wattles for erosion control, shade cloth covered 1-inch mesh fences to harvest water from fog, short-term drip irrigation, and the establishment of native plants. This specific study focused on understanding if there is a significant difference in how much fog derived moisture is being absorbed under various restoration treatments, and at what depth in the soil is moisture the most intense. Data was collected using soil moisture probes and using the gravimetric soil moisture technique on soil samples. Based on a soil moisture index, probe results showed that soil moisture under the fog fence treatment was highest. Both soil probe and gravimetric readings showed that soil moisture is more intense at 10 centimeters than at five centimeters. This study aids in showcasing how and if soil moisture conditions are optimal for plant growth and ecosystem recovery