Vegetation - Garrapata State Park [ds2945]

The study area for this project was Garrapata State Park in northwestern Monterey County, California. Development of Garrapata State Park land by Spanish missionaries began in the late 1700s (Costanoan Rumsen Carmel Tribe 2001). Cattle ranching on the land began in the 1830s with land grants to ranchers, beginning a long stint of grazing on most of the land south of the Carmel River. In 1980, the state of California began purchasing parcels of land and the area was officially classified as a state park in 1985 (Garrapata State Park Monterey Sector 2003). Garrapata State Park encompasses 2,866 acres along the pacific coast, immediately south of Carmel Highlands. The area is largely dominated by steep foothills of the coastal Santa Lucia Range and is dissected by several steep creeks: Wildcat Creek, Malpaso Creek, Soberanes Creek, Doud Creek and Granite Creek. Elevation ranges from sea level to 2,011 ft atop Rocky Ridge. The park also contains an approximately 4.1-mile stretch of coastal bluff, rocky intertidal zone, and beach west of Highway. The park’s Mediterranean climate is characterized by dry summers and cool wet winters and receives approximately 28 inches of mean annual precipitation (PRISM 2012). Wildfire is a prominent disturbance in this landscape; the Soberanes Fire which began in Garrapata State Park in 2016 was one of the largest fires recorded in California history, burning 132,127 acres (CAL Fire 2016). The National Vegetation Classification System allows vegetation to be mapped at three broad levels— physiognomy, biogeography, and floristics—each of which can be broken down into multiple sublevels (USNVC 2020). Floristic-level mapping provides the finest resolution and is the only level to reflect local environmental conditions. Such fine-scale data resolution helps establish a more precise inventory of native and non-native vegetation communities, which benefits land managers interested in protecting valued natural resources, monitoring fuel loads for fire management, and understanding habitat requirements of wildlife. We attempted to map vegetation communities to the alliance sublevel, which is the broadest sublevel at the floristic level of mapping. We did not attempt to map associations, which occur at the level below alliances. Vegetation community mapping comprised preliminary delineation of somewhat homogeneous vegetation stands, field-based classification of alliances and other mapping units, and quality assurance. We first estimated the boundaries of stands using aerial and satellite-derived orthoimagery which were later classified through field observations. Most of the stands we mapped were conformant with previously defined alliances. Non-conformant stands were classified within novel mapping units, defined in Appendix B. We also used novel mapping units for two situations where the exact alliance could not be readily determined in fall; these classes were “Willows” and “Unidentified annual grasses”. We examined aerial and satellite imagery to initially digitize polygons around areas where vegetation looked homogenous and distinct from surrounding areas. We used a mosaic of natural color (red, green, blue [RGB] band) and color infrared (CIR) National Agriculture Imagery Program (NAIP) orthophotos to conduct initial digitizing of vegetation alliance polygons. Polygons were delineated based on areas of visible homogeneity within the landscape; breaks or abrupt changes in color, structure, or relative height of vegetation usually indicated the need to create separate vegetation community polygons. We established minimum mapping units (MMUs) of 0.25 acres for common mapping units and 0.1 acres for uncommon classes, to maximize the level of detail conveyed in vegetation maps given time constraints and clarity of aerial and satellite imagery. The status of each vegetation community polygon was indicated as “unconfirmed” until field crews verified whether initial delineations were correct. Polygons were classified based on the dominant species composition of each polygon. Classification rules were based on rules provided by CNPS, and where rules contradicted each other, we adopted a rule based on either the most recent or the most locally relevant CNPS-listed rule. Most rules were based on the percent cover of the tallest stratum of vegetation. Rules for novel mapping units were that the nominate dominant species should have 50% relative cover. The vegetation map was prepared for publication in California Department of Fish and Wildlife's Biogeographic Information and Observation System by staff from the Vegetation Classification and Mapping Program.