Vegetation - State Vehicle Recreation Areas - 2020 [ds3194]

The California Department of Parks and Recreation contracted Geographical Information Center (GIC) to conduct vegetation sampling across multiple California State Vehicle Recreation Areas (SVRA). The purpose of this map is to characterize the vegetation in various SVRAs, which includes Alameda Tesla, Carnegie, Claypit, Heber Dunes, Hollister Hills, Hungry Valley, Oceano Dunes, Ocotillo Wells and Prairie City. The development of this vegetation map was prompted by the passage of Senate Bill 249, in which California Department of Parks and Recreation’s Off-Highway Motor Vehicle Recreation Division (OHMVRD) was charged with meeting new legislative mandates to ensure resources compliance within all SVRAs. These mandates require (among other things) that OHMVRD compile an inventory of native plant communities within each SVRA [PRC 5090.35 (c)(1)]. To meet this requirement, OHMVRD has consulted the California Department of Fish and Wildlife’s Vegetation Classification and Mapping Program (VegCAMP) to source finescale vegetation maps that cover the SVRA footprint, or, if not available, used the VegCAMP methods to develop new finescale vegetation maps. This finescale vegetation map and associated data is intended to provide an inventory of native plant communities, inform the park’s natural resource management planning including the Wildlife Habitat Protection Plan (WHPP), and establish a baseline for measuring future vegetation change. About the individual SVRAs: Alameda Tesla: The finescale vegetation map for the Alameda Tesla area was created in 2021-2022 using CDFW's VegCAMP standard methods. At the time of surveying, this parcel was part of Carnegie SVRA and was sampled and analyzed together with that project, as part of informing the Carnegie SVRA Wildlife Habitat Protection Plan. However, after the legal separation of these two units in 2021, the mapping projects have also been separated. Carnegie: The finescale vegetation map for Carnegie SVRA was created in 2021-2022 for the park's Wildlife Habitat Protection Plan, using CDFW's VegCAMP standard methods. Field surveys were conducted in 2021. This mapping effort was part of a larger project within the Off Highway Motor Vehicle Division of State Parks to create updated vegetation maps and an inventory of native plant communities for each SVRA. When the project began in 2021, Carnegie SVRA and the adjacent Alameda-Tesla area were sampled and analyzed together. However, because of the legal the separation of these two units in 2021, the mapping projects were separated Clay Pit: Clay Pit SVRA is a small, 220-acre park in unincorporated Butte County, three miles southwest of Oroville. It consists of a narrow terrace surrounding a large bowl-shaped depression that was excavated for clay substrate to use in the construction of the Oroville Dam. It was a popular unofficial off-highway vehicle (OHV) riding area, and became an SVRA in 1981. The entire park is designated as open riding, except for an exclusion zone where a drainage canal flows through the park and into the Feather River oxbow. The park frequently floods from rainfall in wet months, and dries out in the summer. Because of the clay substrate, the shallow depressions formed from OHV use create vernal pools in the spring, providing habitat for native vernal pool plant species and branchiopod species. However, due to the history of disturbance and lack of original topography, many species at the park are ruderal non-natives. Heber Dunes: Heber Dunes SVRA is a small, 364-acre park in unincorporated Imperial County, seven miles northeast of Calexico, and is surrounded by agricultural fields, irrigation canals, and an undeveloped parcel owned by California Department of Transportation (CalTrans). It consists of open sand dunes, planted athel tamarisk (Tamarix aphylla) trees, and native and exotic desert scrub vegetation. The entire park is designated as open riding for off-highway vehicles. Hollister Hills: Hollister Hills SVRA is a 6,750 acre park located in northwest San Benito County, eight miles south of the city of Hollister. It is situated within the Gabilan Range of the California Coast ranges, in an area surrounded by primarily by rangelands. Hungry Valley: Hungry Valley SVRA is a 19,800 acre park within the Transverse Mountain Ranges, just south of Tejon Pass and the town of Gorman. The park is surrounded by National Forest land and by Tejon Ranch. Before becoming a SVRA in 1980, the park had a history of homesteading, mining, and unofficial OHV use. Oceano Dunes: This finescale vegetation map for Oceano Dunes SVRA was created to inform the park's Wildlife Habitat Protection Plan, using CDFW's VegCAMP standard methods. Field surveys were conducted in May 2022 by Chico State Geographic Information Center. Linework was conducted by Chico State Geographic Information Center. State Park staff provided edits to the draft map before it was finalized in 2023. An existing finescale map of the park was completed in 2013 (field surveys done in 2012) by MIG, report available here: https://nrm.dfg.ca.gov/documents/ContextDocs.aspx?cat=VegCAMP. Since vegetation in this park shifts frequently, and since large restoration projects have been conducted since the previous mapping effort, it was determined that an update to the map was needed. Chico State's Geographic Information Center (GIC) sampled the park in 2022 and conducted the linework to create this updated finescale vegetation map, with input from State Park staff. Vegetation was classified using a draft classification for the Santa Cruz-Santa Clara counties project, and by consulting with CDFW staff. Since GIC was also sampling and mapping other central coast State Parks in the region at the same time, the data for Pismo Beach is included here. Ocotillo Wells: This vegetation map was created in 2022-2023 to meet the above requirements and inform the Ocotillo Wells Wildlife Habitat Protection Plan. It was created by combining the existing maps from the DRECP mapping project 2016-2017 additions (Reyes et al.2021), and the Anza Borrego (1998) mapping project (See the VegCAMP website). State park staff including Melissa Patten, Leah Gardner, and Casey Paredes, conducted 25 recon surveys and additional map checks in March 2022 to groundtruth some areas, with a focus on the footprint of the older Anza Borrego project. Linework to edit the Anza Borrego project footprint area was done in 2023 using information from field surveys, and heads-up digitizing of NAIP 2020 imagery. Surveys conducted by State Parks staff in March 2022 focused on the Anza Borrego project footprint within the park, and then linework was done to update the vegetation polygons based on field surveys and 2020 NAIP aerial imagery. Prairie City: Prairie City SVRA is a 1,344 acre park located 20 miles east of Sacramento, in an ecological transition zone between the Central Valley and the Sierra foothills. Parts of the park have a history of dredge mining, and mine tailings form mounds and undulating topography in places. Other portions of the current park were formerly owned by Aerojet and used for a rocket engine program, contaminating groundwater and resulting in modern remediation and groundwater treatment efforts in the park, including monitoring and extraction wells. The imagery interpreted was NAIP 2020No accuracy assessment was done because almost all polygons were visited in the field. Minimum Mapping Units: Alameda Tesla, Carnegie, Heber Dunes, Hollister Hills, Hungry Valley, Prairie City.: The minimum mapping unit was 1 acre for upland vegetation types and ¼ acre for wetland vegetation types. Polygons were divided based on a change in cover class according to Braun-Blanquet categories (<1%, 1-5%, >5-15%, >15-25%, >25-50%, >50-75%, >75%). Breaks for the dominant overstory vegetation cover class required a 3-acre minimum mapping unit, and breaks for understory vegetation cover class required a 5-acre minimum mapping unit. Claypit: The minimum mapping unit was 1 acre, and ¼ acre for wetland or special types, which at the park includes only two small riparian stands and one patch of perennial grassland. The herbaceous stands that compose most of the park were split according to cover, but there was no maximum mapping unit size. Ocotillo Wells, Oceano Dunes: No minimum mapping unit was reported. Imagery: NAIP 2020 imagery was used for all SVRAs.