Santa Cruz Island Reserve

13 Apr, 03 AM - 27 Apr, 08 AM

Abstract: Island oak has been severely impacted by grazing pressures over the last two centuries. Restoration efforts on Santa Rosa, Santa Cruz and Anacapa Islands could be aided if island oak's environmental requirements (soil characteristics, plant community types, slope and aspect) were better understood. Accordingly, I propose to construct a GIS model and conduct ordination analyses of the habitat preferences of the island oak. These models will be used to show where island oak could have been in the past, which is also where restorationists could plant it in the future. Keywords: restoration ecology, island oak, biogeography, soil science, GIS, ordination, phytosociology Overview: Statement of Issue Rarest of California's tree oaks (Pavlik et al. 1991), island oak (Quercus tomentella) is considered by the National Park Service to be a species of special environmental concern and in need of restoration efforts (Junak et. al 1995). Island oak is found naturally only on six California islands: Santa Cruz, Santa Rosa, Anacapa, San Clemente, Santa Catalina, and Guadalupe (off Baja California), but has been cultivated horticulturally (Junak et al. 1995). The main research objective for this project is to investigate the current range of habitats of the island oak (Quercus tomentella) in order to aid future restoration and conservation of both this species, and oaks in general. Field measurements on Santa Rosa and Santa Cruz Islands will be used to construct a geographic information system (GIS) model and conduct ordination analyses of the current range of environmental factors correlated with the island oak, and island oak regeneration, in the Northern Channel Islands. As part of my study, I will investigate whether sexual reproduction is currently significant for the island oak, by measuring seedling recruitment. Like many oak species in California (Brooks and Merenlender, 2001), island oak had regenerated poorly in the last 150 years. Park researchers originally theorized that the tree was relying solely upon clonal reproduction and that it was incapable of regenerating naturally from seed (Halvorsen, 1991). However, in 1998, cattle were removed from Santa Rosa Island and populations of non-native deer and elk were culled substantially by park management. Similarly, sheep were removed from Santa Cruz Island in the early 1990s, and park staff are in the process of removing feral pigs. Park staff continue to reduce the number of non-native herbivores. In addition, as an island ecosystem, the Channel Islands have fewer species of small, native herbivores, which browse oak seedlings and harvest acorns, and have been implicated as major seed predators for valley and coast live oak on the mainland (Tyler et al., 2001). If island oak seedling recruitment has since become significant, this has important implications for possible regeneration in mainland oak ecosystems. Habitat models that compare current distributions of a particular species to hypothesized causal factors have been frequently employed for purposes of conservation and restoration of animal species. Utilizing a multiple logistic regression, Franco et al. (2000) found that common crane (Grus grus) distribution was negatively related to distance from open holm oak (Quercus rotundifolia) woodlands and roosts, and that the cranes avoided orchards, unsuitable vegetation, roads and villages. Similarly, a study by Ganey et al. (2000) examined roost sites of Mexican spotted owls (Strix occidentalis lucida) and discovered that roosts in pine-oak forest were more likely to occur on moderate slopes, on southwest to northwest aspects, and on the higher portions of slopes. In an effort to restore bighorn sheep (Ovis canadensis) to several national parks, researchers utilized a GIS to identify 73 potential habitats (Singer et al. 2000); subsequently the bighorn sheep were translocated to 36 of these sites. A follow-up study (Zeigenfuss et al., 2000) showed that the habitat suitability model for bighorn sheep was 64% accurate in predicting success or failure of the translocations. Habitat models constructed for purposes of plant conservation and restoration are less common; indeed, in general, there is a large need for developing new approaches for monitoring and recovering rare plants (Pavlik, 1997). In instances where historical data is available, comparisons of historical and current vegetation cover can be drawn (Radeloff, 1998; Brooks and Merenlender, 2001). A recent study of oak regeneration in a northern coastal region following human clearing, burning and application of herbicides, found that some natural regeneration did occur, and that it occurred preferentially with respect to slope, aspect, and soil type (Brooks and Merenlender, 2001). Regeneration was mostly by evergreen oak species (interior live oak, Quercus wislizenii) on moister and steeper northerly slopes, and was most commonly associated with Josephine, Los Gatos, and Maymen soils. The change in vegetation cover with respect to physiographic and biological parameters was analysed by utilizing a GIS. However, when historical data or reference sites are lacking, restoration biologists need alternative methodologies when setting their target goals or performance standards. One approach is to develop a habitat model based on ecological requirements that are described for the species and its close relatives in the scientific literature (Zalba et al., 2000). Using this method, Zalba et al. evaluated habitat quality for the germination and establishment of seedlings of Atriplex nummularia, an invasive weed, according to slope, soil microtopography, susceptibility to flooding of the soil, and other factors. This approach, however, would be difficult to apply to island oak because very little has been published about its purported ecological requirements. One rare plant habitat model was generated for a subspecies of the endemic island ironwood, Lyonothamnus floribundus subsp. asplenifolius, using a logistic regression and based upon the following explanatory variables: geologic substrates, geologic features, aspect, elevation, slope, and plant community (Junak, 1987). This research examined all ironwood stands on Santa Cruz Island, whereas my research on island oak will adapt the approach to consider two islands and examine the possibility of an island effect. In addition, my study will differ in that I will consider the effect of environmental factors upon seedling recruitment, and I will add detailed soils data to the list of explanatory variables. Relevant literature Brooks, C. N. and A. M. Merenlender. 2001. Determining the pattern of oak woodland regeneration for a cleared watershed in northwest California: a necessary first step for restoration. Restoration Ecology, 9(1): 1-12. Buol, S. W., F. D. Hole, R. J. McCracken, and R. J. Southard. 1997. Soil Genesis and Classification. Fourth edition, Iowa State University Press. Butterworth, J.B., J.A. Jones and S. Jones. 1992. Soil forming factors, morphology and classification-Santa Cruz Island, California. In: Hochberg, F.G. (ed.), Third California Islands Symposium-Recent Advances in Research on the California Islands, Santa Barbara Museum of Natural History, pp. 39-44. Dibblee, T. W., J. J. Woolley, and H. E. Ehrenspeck. 1998. Geologic map of Santa Rosa Island, Santa Barbara County, California. Published by the Dibblee Geological Foundation. Franco, A. M. A., J. C. Brito, and J. Almeida. 2000. Modelling habitat selection of Common Cranes Grus grus wintering in Portugal using multiple logistic regression. Ibis 142: 351-358. Ganey, J. L. and W. M. Block. 2000. Roost sites of radio-marked Mexican Spotted Owls in Arizona and New Mexico: Sources of variability and descriptive characteristics. Journal of Raptor Research 34(4): 270-278. Griffin, J. R. 1995. Oak woodland. In: Barbour, M.G. and J. Major (eds.), Terrestrial Vegetation of California, California Native Plant Society, pp. 384-415. Halvorson, W. L. 1991. The status of two endemic woodland species on Santa Rosa Island, California, USA. Bulletin of the Ecological Society of America, vol. 72, no. 2 suppl., p. 134. Holland, F. R. 1962. Santa Rosa Island: An archeological and historical study. Journal of the West, 1(1-2):45-62. Jones, J.A. and D. Grice. 1993. A computer-generated soils map of Santa Cruz Island, California. In: Hochberg, F.G. (ed.), Third California Islands Symposium-Recent Advances in Research on the California Islands, Santa Barbara Museum of Natural History, pp. 45-56. Jones, J.A., S.A. Junak and R.J. Paul. 1993. Progress in mapping vegetation on Santa Cruz Island and a preliminary analysis of relationships with environmental factors. In: Hochberg, F.G. (ed.), Third California Islands Symposium-Recent Advances in Research on the California Islands, Santa Barbara Museum of Natural History, pp. 97-104. Junak, S. A. 1987. Environmental factors correlated with the distribution of island ironwood (Lyonothamnus floribundus subsp. asplenifolius). M.A. thesis, UC Santa Barbara. Junak, S.A., T. Ayers, R. Scott, D. Wilken and D. Young. 1995. A Flora of Santa Cruz Island, Santa Barbara Botanic Garden and the California Native Plant Society. Kent, M. and P. Coker. 1992. Vegetation description and analysis: a practical approach. John Wiley & Sons, New York, pp. 247-264. Manos, P. S., J. J. Doyle, and K. C. Nixon. 1999. Phylogeny, biogeography, and processes of molecular differentiation in Quercus subgenus Quercus (Fagaceae). Molecular Phylogenetics and Evolution 12(3): 333-349. Minnich, R. A. 1980. Vegetation of Santa Cruz and Santa Catalina Islands. In: Power, D. M. (ed), The California Islands: Proceedings of a multidisciplinary symposium, Santa Barbara Museum of Natural History, pp. 123-137. Pavlik, B. M. 1997. Perspectives, tools, and institutions for conserving rare plants. The Southwestern Naturalist 42(4): 375-383. Pavlik, B.M., P.C. Muick, S.G. Johnson and M. Popper. 1991. Oaks of California, Cachuma Press and the California Oak Foundation, pp. 34-35. Radeloff, V. C., D. J. Mladenoff, K. L. Manies, and M. S. Boyce. 1998. Analyzing forest landscape restoration potential: pre-settlement and current distribution of oak in the northwest Wisconsin pine barrens. Transactions of the Wisconsin Academy of Sciences, Arts and Letters 86: 189-206. Singer, F. J., V. C. Bleich and M. A. Gudorf. 2000. Restoration of bighorn sheep metapopulations in and near western national parks. Restoration Ecology 8(4S): 14-24. Soil Survey Staff. 1999. Keys to Soil Taxonomy. Eighth edition, Soil Conservation Service, U.S. Department of Agriculture, Pocahontas Press, Inc., Blacksburg, Virginia. Tyler, C. M., B. E. Mahall, and F. W. Davis. 2001. Factors limiting recruitment in valley and coast live oak. In: Conference literature, "Oaks in California's Changing Landscape: Fifth Symposium on Oak Woodlands," Oct. 22 to 25, San Diego, California. Zalba, S. M., M. I. Sonaglioni, C. A. Compagnoni, and C. J. Belenguer. 2000. Using a habitat model to assess the risk of invasion by an exotic plant. Biological Conservation 93: 203-208. Zeigenfuss, L. C., F. J. Singer and M. A. Gudorf. 2000. Test of a modified habitat suitability model for bighorn sheep. Restoration Ecology 8(4S): 38-46. Scope of study In order to map and analyze a potential range in environmental factors as related to the island oak, I plan to sample soils and collect plant community, slope, and aspect data in island oak groves, near individual trees, and in areas with no island oak in 20 different locations on Santa Rosa and 20 locations on Santa Cruz Islands. Intended use of results The outcome of this research should provide useful information for management of the island oak in Channel Islands National Park with respect to its environmental preferences. This information could be useful to park staff who are making decisions regarding collection of acorns, seedling propagation, and planting of oak seedlings in restoration efforts. GIS data layers created by Laura Kindsvater during the study (e.g., of oak populations) will be given to NPS staff. Research results will be reported in Laura Kindsvater's Ph.D. dissertation. Nothing of commercial use will be derived from this study. Objectives: The main research objective for this project is to investigate the current range of habitats of the island oak (Quercus tomentella) in order to aid future restoration and conservation of both this species, and oaks in general. Field measurements on Santa Rosa and Santa Cruz Islands will be used to construct a geographic information system (GIS) model and conduct ordination analyses of the current range of environmental factors correlated with the island oak, and island oak regeneration, in the Northern Channel Islands. The island oak habitat model generated by my research is intended to help island restorationists decide where to plant island oak seedlings based on the most likely habitat requirements or preferences of island oak. It is not known how broad the distribution of the species was 150 years ago, before the advent of heavy sheep grazing--as many as 125,000 sheep were reported on Santa Rosa Island at the end of the nineteenth century (Holland, 1962), but it is believed that much of the vegetation was destroyed by starving sheep during droughts in the late 1800s. Island oak is a paleoendemic species, thought to have evolved in a climate cooler and wetter than California's current climate, perhaps 7 to 20 million years ago (Pavlik et al., 1991). Therefore, the most likely reason that its current natural distribution is restricted to California islands is that it has fairly stringent water requirements, and the islands' maritime climates offer habitats with more effective precipitation. With respect to the question of how soil and plant community requirements limit island oak recruitment, I have developed the following hypotheses, which may be tested in combination using a multivariate approach. 1. Island oak (in its arboreal form, and in its purest morphological forms) will be mostly or entirely found in areas with a high availability of precipitation or stream flow (e.g. ridgetops that catch fog or canyon bottoms; Chaney 2001, Pavlik et al. 1991). 2. Island oak will be frequently found in soils with increased clay content or depth (characteristics that increase water-holding capacity). 3. Island oak will grow more frequently on north-facing slopes than on south-facing slopes (Jones et al. 1993). 4. Island oak will be most frequently found in riparian woodland, followed by chaparral. 5. Island oak seedlings will be more numerous in those soils containing some volcanic parent material (Jones et al. 1993, Dibblee et al. 1998), perhaps due to elevated nutrient levels. Methods: Description of study area In order to map and analyze a potential range in environmental factors as related to the island oak, I plan to sample soils and collect plant community, slope, and aspect data in island oak groves, near individual trees, and in areas with no island oak in 20 different locations on Santa Rosa and 20 locations on Santa Cruz Islands. On Santa Rosa, I will sample in island oak groves along Main/Burma roads, on Black Mountain, in upper Water Canyon, and in Cherry Canyon. On Santa Cruz, I will sample in island oak groves on the isthmus, on Diablo Peak, and on Alta 2. Maps of proposed soil sampling sites will be provided to the park in advance. Procedures Mapping of oak trees on Santa Rosa Island has been partially completed using Trimble GPS units. This information will be exported into a text file and then into Arc/Info or ArcView by Laura Kindsvater. It will be combined with existing vegetation coverages and aerial photos to generate a map of where island oak are located. At the selected sampling sites, I will collect the following data: number of island oak stems in each of 5 size classes (seedling, sapling, browsed shrub, young tree, and older tree), percent slope (using a clinometer), aspect (using a compass), geographic location (using a GPS unit), plant community data (using the Braun-Blanquet releve method, Kent and Coker 1992), and soil samples. On Santa Rosa, the climate and water availability of each site location will be interpolated from meteorological station data using elevation, slope, aspect, and windward/leeward position. Complete field descriptions of soils will be made using standard soil survey methods (Buol et al., 1997; Soil Survey Staff, 1999). For each site, I will use a soil augur or soil probe to core in 5 to 7 places. I will remove one core from the A horizon and one core from the B horizon of the soil. These will be taken back to UC Davis for analysis by the DANR laboratory. Elevation will be derived from the USGS digital elevation model and compared to the elevation recorded by GPS. The measurements of slope, aspect, stand location, plant community type, soil variables, moisture availability, and elevation will be imported into a GIS and the density of island oak, as well as the number of seedlings, will be analyzed with respect to the potential determining factors. A habitat model will be constructed and ordination analysis conducted for the Northern Channel Islands, with comparisons drawn between the islands, using Arc/Info GIS software and CART statistical software. Collections Soil samples will be collected at each site in order to analyze the following: particle size (percent clay, silt, sand), soil fertility (N, P, K), micronutrients (zinc, copper, manganese), organic matter, bulk density, electrical conductivity, water holding capacity, and pH. For each sampling point, soil samples will be collected from A and B horizons. This is equivalent to about two pint-size containers of soil per sampling point. The soil samples will be processed in the UC Davis Division of Agriculture and Natural Resources (DANR) Analytical Laboratory. To aid in plant community classification, plant samples will also be collected. The amount of plant material needed is small (a twig with a few leaves, a flower or fruit if available). No state or federally listed species will be collected. Plant specimens will either be deposited at the UC Davis Herbarium or the Santa Barbara Botanic Garden Herbarium. Analysis Analysis and modeling will be conducted using Arc/Info, CART and PC-ORD, which are available on the UC Davis campus. Methods of analysis will include regression trees and ordination. Schedule Mapping of island oak populations on Santa Rosa was conducted in the summer of 2001. Plant community surveys began on Santa Rosa and Santa Cruz in July through September of 2002. GIS analysis and modeling will began in the fall of 2002. I would like to conduct plant community and soil surveys from mid-April to mid-May of 2003, with follow-up plant community surveys in July of 2003 and follow-up soil surveys in winter of 2003 (after the first rains). Field work should be completed by December of 2004 and the dissertation should be completed by June of 2005. Budget This project is being funded by UC Davis Jastro-Shields research awards, work study funds provided by Dr. Deborah Elliott-Fisk, and personal funds. Expenses include travel to and from the site, housing or campground fees, subsistence, film purchase and development, and soil and plant sample processing. I will also continue to apply for fellowships from the Canon Park Scholar program and the University of California system. Products Publications and reports See "intended use of results" section above. Collections All soil samples collected during this project will be consumed during analysis. Plant samples will be deposited at either the UC Davis Herbarium or the Santa Barbara Botanic Garden in order to aid in their identification. Data and other materials I will photograph the study sites periodically during the study. I will produce a GIS coverage of the known locations of island oak on Santa Rosa Island and distribute it to NPS staff. I will generate a GIS model that will predict ideal habitat for island oak and give it to NPS staff. Literature cited See "relevant literature" above. Qualifications Laura Kindsvater has experience in mapping using a GPS and in conducting GIS modeling of oak populations. She is trained in botanical field identification, soil surveys, and vegetation classification techniques. See attached curriculum vitae for more information. Her permit was approved in fall of 2002. Supporting documentation and special concerns Safety Mapping of oaks may include traveling on steep terrain. I have made and will continue to make every effort to avoid unnecessary risks and be as careful as possible. Access to study sites Several island oak populations are fairly close to roads. Others are located in canyons, which can be accessed by hiking in from a road. I anticipate no need to enter any restricted areas. Use of mechanized and other equipment Soil surveys may require the use of a shovel, pick, soil probe, and/or soil augur. After each survey, the soil will be returned to the pit and the equipment removed. Marking of location will usually be done using a GPS, although in some cases plastic flagging may be used. Chemical use No chemicals will be needed for this study's field work. Ground disturbance Soil samples will be collected after the park archaeologist has determined that the collections will not disturb an archaeological or cultural site. The samples will be collected using soil probe, soil augur, shovel and/or pick depending on the hardness and rockiness of the soil. Animal welfare n/a NPS assistance It would be helpful if NPS staff could provide vehicle transportation to the study sites or their vicinity, on Santa Rosa Island. If NPS housing is not available at the time of my visits, I am comfortable with camping. Wilderness "minimum requirement" protocols n/a

Visit #1095 @Santa Cruz Island Reserve

Approved

Under Project # 929 | Research

Quercus tomentella spring fieldwork

volunteer - University of California, Davis

Reservation Members(s)

Laura Kindsvater Apr 13 - 27, 2003 (15 days)
Laura Kindsvater Apr 13 - 27, 2003 (15 days)

Reserve Resources(s) | Create Invoice

Dorm 2 Apr 13 - 27, 2003