Stoney Point rock formation and city park, in the western San Fernando Valley. A Los Angeles Historic-Cultural Monument located near Chatsworth Park North, in Chatsworth, Los Angeles, California From: http://commons.wikimedia.org/wiki/File:Stoney_Point_Outcroppings.jpg
Flora of Eight Transects at Stoney Point: Significance Indications of Transition from CSS to Chaparral at Intersecting WTR and SCo region of California Floristic Province
Samantha Antu, Justin Chong, Gary Crethers, and Natalie Espinoza
Report written by Crethers. Data collected by Antu, Chong, Crethers and Espinoza.
Photos and tables as credited.
The flora data from eight transects taken in the southwest region of the Stony Point Park, Chatsworth area of Los Angeles County, was used to determine the vegetation type community according to the University of California Natural Reserve System and the Jepson Manual, Hierarchical Outline of Geographic Subdivisions. The data compared with data from three other groups examining other locations in the SW region of CA-FP, using Chi data analysis initially and then using Alpha, Beta and Gamma Biodiversity analysis. The determination that the vegetation in the Stony Point region was so divergent from that of the other regions, all of which were in the CSS, led to the tentative conclusions that this was a hard Chaparral plant community with some aspects of valley and foothill woodland vegetation. The plants in the region were suffering from prolonged drought conditions making plant species identification problematic. The constant use of the area by rock climbers also affected the vegetation. The authors recommend further study, including historical plant data correlated with climatic conditions and disturbance factors.
The Stony Point Park is a seventy-six acre complex of trails around a rocky outcrop located in the western region of the Valley in Los Angeles near the intersection of the 118 Highway and Route 27 Topanga Canyon Road, approximately 20 miles from the Pacific Ocean. This is an area where the California Floristic province or CA-FP, SW region (southwest region), WTR (western transverse region) intersects with the SCo (south coast) (Hickman; 1993, 44-45). The plant communities of this area are described in the NCR (University of California Natural Reserve System) as “Chaparral (Hard Chaparral) same in Muntz” and the “Valley and Foothill Woodland (includes Northern, Southern Oak Woodland; and Foothill Woodland)” (Ornduff, Faber and Keeler-Wolf; 2003, 115-118). The area is part of the Chatsworth Formation the oldest geological formation in the Simi Valley region, forming in the Upper Cretaceous period 75 to 70 million years ago. Sandstone is the major component of this formation originally part of deposits left by turbidity currents in a submarine canyon creating deposits 6000 feet thick. The transverse zone created by the end of subduction 30 million years ago with the beginning of the transverse slippage process by which the Pacific plate is moving in a northwesterly direction relative to the North American plate represented by the San Andreas fault has created the current geological conditions. Layers of grayish rock when exposed to weathering appear brown to reddish brown in layers of thick sandstone interleafed with thin layers of mudstone (Squires; 1997a, 294-296), figure 1.
Figure 1 us geological survey paper 1515 san andreas]fault 1990-1991. Map shows elevations.
The region fragmented in terms of urban development in relationship to natural ecosystems. Stoney Point itself is a popular rock climbing and hiking area. The area transected could be qualified as disturbed with many hikers seen tramping around the sites. There is a horse stable directly adjacent to the south of the region we selected. Datura Wrightii, the first species examined seemed to prefer the disturbed area with a lot of human activity. Stoney Point is part of the Mediterranean climate zone (mild, wet winters and hot dry summers), which has recently been undergoing drought conditions which may be a reflection of climate change. Recent studies of Brassica rapa have indicated that evolutionary change is occurring in species as well as natural plant plasticity (Franks, and Weis; 2008). Drought in the region cannot be specifically determined to be a result of warming in the SST due to the contradictory effects of the high abnormality over the eastern Pacific and the increased atmospheric humidity (Wang and Schubert; 2014). The vegetation is dispersed with clumps of denser vegetation near the dry water channel and at the edge of the horse stable and homes where there may be some runoff creating the potential for an oasis like microclimate, although no water flow was observed. These species included Centaurea melitensis, Quercus agrifolia, Rhus ovata, and Eucalyptus globulus. The rocky southern slope of the hill studded with large boulders that provide some shelter for vegetation. Stipa coronata especially seemed adapted to this environment. Santa Ana winds are particularly strong in the region, with the author experiencing gusty winds on a second visit to the site.
Materials and Methods
The group used a tape measure to divide each transect into segments of 1 meter over a 10 meter length for 11 identifications each. GPS data gathered at the beginning and end of each transect using GPS Status data available as an app for cell phones. The closeness to the rock wall of the hillside and some of the larger boulders made readings less than 100 percent reliable. Data was recorded manually on transect forms with pen and pencil with the tasks being shared by all participants. Eight transects were taken, sampling two on the trail entering the site from the Topanga Canyon Road. There was one transect taken among the rocks on the south side ridge of Stoney Point. One transect taken in a grove of trees among sheltering boulders. Another three transects were done along the dry watercourse and a final transect was made among trees that were on the edge of the park paralleling a housing development to the south. The choices made sampling different terrains and vegetation in a random manner as we moved in an easterly direction, and then doubled back for the last transects. Antu, Chong, Crethers, and Espinoza took data sampling on November 8, 2014. Crethers did a follow up on November 16,, 2014.
Plant identification was done with a combination of photographic images taken on the spot and cuttings from species observed at the transect points. The images checked against Calflora, Google images, the NPIN: Native Plant Database at Wildflower.org, Wiki articles, Jepson Manual of Higher Plants and Introduction to California Plant Life as well as consulting with Professor Rodrigue who initiated the research site and methodology proposal. The plant data analyzed by Gary Crethers and Justin Chong; Chong then created an excel spreadsheet with the data. This data further modified by Crethers and Professor Rodrigue and reviewed by Antu and Espinoza. The data gathered was subject to a Chi-square test by Samantha Antu, and then Antu performed a comparison analysis with alpha, beta and gamma diversity tests against the data gathered by three other groups for the Southern California region. These included data from transects taken from the Bolsa Chica Wetlands, Palos Verdes at the Portuguese Bend Reserve, and Sepulveda Basin Wildlife Reserve.
The identifications hampered by the extremely dry conditions of the drought. (Swain et. al., 2014, S3; Wang and Schubert, 2014, S7). See figure 2.
Figure 2 California Precipitation over long historical periods. From: http://icons.wxug.com/hurricane/2014/pdsi-ca-dec-2013.png
Plant images for identification purposes were almost universally from when the plants are flowering. There were large areas with no visible plant life or unidentifiable plant debris. Of the 88 separate identification locations, 38 were bare ground or rock face or 43 percent of the area. This indicates the discontinuous nature of the vegetation. Species tended to clump together. Only twelve species identified in transects with dirt being the most common. Only twelve species identified in transects with dirt being the most common. See Table 1 below.
Chi-Square results showed the region to be anomalous in relationship to the other groups. Bolsa Chica Reserve and Portuguese Bend Reserve are both CSS environments directly on the Pacific coast. Sepulveda Basin Reserve has riparian CSS, with indications of a transition to the chaparral of the WTR, as the SepulvedaF14 data shows. Species Salix goodingii, or Gooding’s willow, Baccharis salicifoila, or mule fat, and Baccharis pilularis, or coyote brush, predominant in the groups transects, indigenous species. Whereas Datura wrightii, jimsom weed, Ambrosia psilostachya, or ragweed, and Hirshfeldia incana or Mediterranean Mustard predominated in StonyPointF14 data, with ragweed and mustard both invasive species, according to the results posted by Rodrigue (Geog.442, 2014).
The Alpha Beta diversity comparison below indicates the degree of diversity of the other sites. We have twelve different species at Stoney Point indicating the least diversity among the sites. But then when compared to the other sites on the Beta diversity Stoney Point has the least divergence with Sepulveda and the greatest with Bolsa Chica. The Gamma diversity of the region is 52.
Figure 3 Alpha Beta Diversity comparing Stony Point Data to the other three sites (Samantha Antu 2014).
That would indicate that geographical distance maybe significant as a factor, as Bolsa Chica is the furthest away from Stoney Point at approximately 50 miles. Palos Verdes is next at 38 miles and Sepulveda is closest at 10 miles, but physical distance is not necessarily significant in and of itself, if the climatic conditions are the same over the entire regional environment. A more important factor would be the distance from the maritime influence of the ocean. As has been stated, Stoney Point is 20 miles from the Pacific Ocean. It is almost due north from the mouth of Topanga Canyon. Bolsa Chica and Palos Verdes sites are both less than a mile from the Pacific Ocean. Sepulveda site is approximately 10 miles from the ocean, almost exactly half the distance that Stoney Point is from the Ocean. Looking at the topography, the Palos Verdes site has a rapid increase of altitude from near sea level at about 50 meters to 280 meters or almost 1000 feet. Bolsa Chica has elevations that are all very near sea level all less than 5 meters, 15 feet or less elevation. Sepulveda is on the other side of the Mulholland Pass. It is a riparian site with the LA River running through it and as figure above indicates it is in the 205 to 220 meters altitude range about 600 feet. Whereas the Stoney Point readings were at about the 310-340 meter level over 1000 feet. Elevation in itself clearly is not the distinguishing factor. A combination of elevation, distance from the ocean, wind currents affecting rainfall, whether or not the microclimate is within a rain shadow or not all are factors. Stoney Point partially blocked by the higher Simi Hills to the west and the Santa Monica Mountains to the south does not benefit as directly from the coastal CSS climate as the other areas.
Figure 4 California Floristic Province Map from the Jepson Herbarium From: http://ucjeps.berkeley.edu/IJM_geography.html
The constant influx of visiting humans and the proximity to residential areas, provide many opportunities for invasive species to infiltrate the park that is isolated from the larger, more natural ecosystems of the Simi Hills. The species along the dry watercourses were a mixture of introduced species such as the Eucalyptus globulus, brought from Australia to provide drought resistant timber in the nineteenth century, Rhus Ovata or sugar bush, and Quercus agrifolia, or coast live oak. The last two are native and the coast live oak used by Native Americans for the acorns to produce one of their dietary staples. This expected as the climatic conditions change from SCo with its milder temperature range due to the mitigating effects of the maritime ecosystem along the coast inland. In addition, the coastal fog in the summers mitigates the transfers a greater degree of moisture to coastal plants spared some of the effects of the hotter and dryer conditions as one moves inland. The hot, dry summers and cool wet winters reflect a Mediterranean climate, which transits to a montane environment moving inland and upland, with its Chaparral, Valley, and Foothill ecosystem.
The results would tend to indicate with the lack of shared species, that the Stoney Point data is from a different plant community, than that directly on the Pacific coast, in this case identified as Chaparral and Valley and Foothill Woodland. Dirt appearing as the most common identifier indicates the lack of foliage density. This seems to be the result of human use of trail areas and the severe drought conditions have caused many species to die back and subsequently become hard to identify. Still we concluded the species reflect those found in Inland Scrub or Chaparral zone. Twenty miles from the ocean, species in Stoney Point have more of the characteristics of species found in the inland scrub rather than CSS, although identification was somewhat problematic. The group bolstered fieldwork by checking the Jepson Manual of Higher Plants and Introduction to California Plant Life area maps to confirm this conclusion. See Figure 4 above.
Prepare a historical study of introduction of invasive species and the advisability of removing them from such a small ecological island.
Pre-Colonial Indigenous influence on species and habitat has been profound and needs further research, see Appendix 1.
Effects of Climate change and extended drought on whether the CSS area is reduced and replaced by Chaparral species or if the opposite occurs or some more complex adaptation.
The Urbanization effect on habitat and species resilience, including the effects of pollution, small versus large ecological islands and the possible linking of the park with other areas to provide corridors for native fauna and flora is another area for further study.
Appendix 1: Notes on Native American Land Use and Datura Wrightii
Datura Wrightii used by the indigenous people of the region for a variety of purposes. According to Edward D. Castillo in his article on California Native Americans, Datura or Jimsonweed was used male puberty rituals due to its hallucinogenic properties (Castillo 1998). The area around Stony Point was a traditional site for the local Tataviam tribal people called Momonga and was a mortuary area according to the tribal web site of the Fernandeño Tataviam Band of Mission Indians. They also claim the use of jimson weed in the making of baskets. “The historical Tataviam ate acorns, yucca, juniper berries, sage seeds and islay, and they hunted small game. Jimsonweed, native tobacco, and other plants found along the local rivers and streams provided raw materials for baskets, cordage, and netting” (Fernandeño Tataviam Band, History).
“Momoy (Chumash) – Datura wrightii
Also called California Jimson Weed or in Spanish, toloache, this small bush is common in disturbed areas and often considered one of the most sacred plants in the Chumash world. According to Cecilia, Momoy protects and tickles the soul, brings you back to earth. Ingestion of the root mixture would initiate young boys or girls into adulthood and can induce sacred dreams or hallucinations. Unfortunately, the dreaming-dose can inhibit breathing, become poisonous, or induce blindness. It can be dangerous or deadly, and not recommended outside of sacred, not psychedelic, Chumash ceremonies. In small amounts it can help a patient breathe as aromatherapy mixed with yerba santa leaves (Eriotdictyon crassifolium) or destress as a foot soak” From: http://www.wilderutopia.com/health/self-healing-with-chumash-native-plant-medicine/
The issue of how First Nation Californians managed their ecosystems largely through controlled burns and the introduction and removal of species makes the issue of what is native, even more complex. The example of the fox population on the Channel Islands has become an issue as Sharon Levy points out that there are strong indications that the fox was introduced by Chumash or other early human arrivals (Levy 333), which has become controversial in determining how far back one should go in restoring original ecosystems. It also brings up the question as to whether there is such a thing as an original ecosystem since the complex nature of the environment is constantly adapting and changing, at what point is restoration simply advocacy for an ideological position? Standards seemingly based on some aesthetic of diversity as an aspect of beauty, rather than a vain attempt to recreate a frozen moment in time because of some purported scientific reason, or perhaps based on the best pragmatic determination as to what will enhance our own survivability. Self-interest ecology seems like it might appeal to the rightward shift in Congress for continued funding.
Jan Timbrook points out that before the arrival of Europeans the local Chumash and Tongva peoples used controlled burns to modify the natural environment. The practice ended by the Spanish missionaries causing the ecosystem to change and gradually lose much of the character it had at the time of the arrival of Europeans (Timbrook, 244). This has led some such as Kat Anderson and Michael Moratto to suggest that the Native American land use practices led to much healthier forests in the Sierra Nevada and bringing Naïve practices back into use. The claim is that protection of supposedly pristine eco-islands is not even historically an accurate view of pre-invasion California, particularly in the Sierra Nevada Mountains (Anderson and Moratto, 187-188).
Certainly a deeper look at what is the natural environment to be preserved needs to take into account thousands of years of Native American husbandry practices as well as the world wide phenomena going back perhaps hundreds of thousands of years in Africa in particular.
If you would like to see the original paper in full color you can contact me at “Garyrumor2@yahoo.com” and will gladly email you the article.
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