DOI: 10.7280/d1f30c
title: Vegetation Classification for the Nature Reserve of Orange County

description: The ultimate goal of this project is to create an updated fine‐scale
 vegetation map for about 58,000 acres of Orange County, consisting of the
 37,000‐acre Orange County Central and Coastal Subregions Natural Community
 Conservation Plan (NCCP)/Habitat Conservation Plan (HCP) Habitat Reserve
 System; approximately 9,500 acres of associated NCCP/HCP Special Linkages,
 Existing Use Areas, and Non‐Reserve Open Space; and approximately 11,000
 acres of adjoining conserved open space (study area). The project
 consisted of three phases.Phase 1: To update vegetation mapping, the
 Natural Reserve of Orange County (NROC) proposes to use Manual of
 California Vegetation (MCV) methods (2009), which will be implemented in
 two stages: Stage 1 – Development of a vegetation classification system
 for the Central and Coastal Subregions of Orange County that is consistent
 with the MCV. Stage 2 – Application of the vegetation classification
 system to create a vegetation map through photointerpretation of available
 aerial imagery and ground reconnaissance. The MCV methods were developed
 by the California Department of Fish and Game (CDFG) Vegetation
 Classification and Mapping Program in collaboration with the California
 Native Plant Society (CNPS). This approach relies on the collection of
 quantifiable environmental data to identify and classify biological
 associations that repeat across the landscape. For areas where
 documentation is lacking to effectively define all of the vegetation
 patterns found in California, CDFG and CNPS developed the Vegetation Rapid
 Assessment Protocol. This protocol guides data collection and analysis to
 refine vegetation classifications that are consistent with CDFG and MCV
 standards. Based on an earlier classification by Gray and Bramlet (1992),
 Orange County is expected to have vegetation types not yet described in
 the MCV. Using the MCV approach, Rapid Assessment (RA) data was collected
 throughout the study area and analyzed to characterize these new
 vegetation types or show concurrence with existing MCV types.Phase 2:
 Aerial Information Systems, Inc. (AIS) was contracted by the Nature
 Reserve of Orange County (NROC) to create an updated fine-scale regional
 vegetation map consistent with the California Department of Fish &
 Wildlife (CDFW) classification methodology and mapping standards. The
 mapping area covers approximately 86,000 acres of open space and adjacent
 urban and agricultural lands including habitat located in both the Central
 and Coastal Subregions of Orange County. The map was prepared over a
 baseline digital image created in 2012 by the US Department of Agriculture
 – Farm Service Agency’s National Agricultural Imagery Program (NAIP).
 Vegetation units were mapped using the National Vegetation Classification
 System (NVCS) to the Alliance level as depicted in the second edition of
 the Manual of California Vegetation (MCV2). One of the most important data
 layers used to guide the conservation planning process for the 1996 Orange
 County Central & Coastal Subregion Natural Community Conservation
 Plan/Habitat Conservation Plan (NCCP/HCP) was the regional vegetation map
 created in the early 1990s by Dave Bramlett & Jones &
 Stokes Associates, Inc. (Jones & Stokes Associates, Inc. 1993). Up
 until now, this same map continues to be used to direct monitoring and
 management efforts in the NCCP/HCP Habitat Reserve. An updated map is
 necessary in order to address changes in vegetation makeup due to
 widespread and multiple burns in the mapping area, urban expansion, and
 broadly occurring vegetation succession that has occurred over the past 20
 years since the original map was created. This update is further necessary
 in order to conform to the current NVCS, which is supported by the
 extensive acquisition of ground based field data and subsequent analysis
 that has ensued in those same 20 years over the region and adjacent
 similar habitats in the coastal and mountain foothills of Southern
 California. Vegetative and cartographic comparisons between the newly
 created 2012 image-based map and the original 1990s era vegetation map are
 documented in a separate report produced by the California Native Plant
 Society at the end of 2014.Phase 3: The California Native Plant Society
 (CNPS) Vegetation Program conducted an independent accuracy assessment of
 a new vegetation map completed for the natural lands of Orange County in
 collaboration with Aerial Information Systems (AIS), the California
 Department of Fish and Wildlife (CDFW), and the Nature Reserve of Orange
 County (NROC). This report provides a summary of the accuracy assessment
 allocation, field sampling methods, and analysis results; it also provides
 an in-depth crosswalk and comparison between the new map and the existing
 1992 vegetation map. California state standards (CDFW 2007) require that a
 vegetation map should achieve an overall accuracy of 80%. After final
 scoring, the new Orange County vegetation map received an overall user’s
 accuracy of 87%. The new fine-scale vegetation map and supporting field
 survey data provide baseline information for long-term land management and
 conservation within the remaining natural lands of Orange County.Data made
 available in the OC Data Portal in partnership with UCI Libraries.
description: The project consisted of three phases, each with its own methodology.
 
 Phase 1: To update vegetation mapping, the Natural Reserve of Orange
 County (NROC) usedManual of California Vegetation (MCV) methods (2009),
 which will be implemented in two stages: Stage 1 – Development of a
 vegetation classification system for the Central and Coastal Subregions of
 Orange County that is consistent with the MCV. Stage 2 – Application of
 the vegetation classification system to create a vegetation map through
 photointerpretation of available aerial imagery and ground reconnaissance.
 
 Phase 2: Aerial Information Systems, Inc. (AIS) was contracted by the
 Nature Reserve of Orange County (NROC) to create an updated fine-scale
 regional vegetation map consistent with the California Department of Fish
 & Wildlife (CDFW) classification methodology and mapping standards.
 
 Phase 3: The California Native Plant Society (CNPS) Vegetation Program
 conducted an independent accuracy assessment of a new vegetation map
 completed for the natural lands of Orange County in collaboration with
 Aerial Information Systems (AIS), the California Department of Fish and
 Wildlife (CDFW), and the Nature Reserve of Orange County (NROC).
 
 For more detailed methodology information please consult the README.txt
 file included with dataset.