Look for complete geospatial metadata in this layer's associated xml document available from the download link * Metric Name: Least Bell’s Vireo Suitable Nesting Habitat * Tier: 2 * Data Vintage: 2020 * Unit Of Measure: Thematic, suitable riparian vegetation types that include at least 15% shrub willow/mulefat cover and/or >15% tree willow cover. * Metric Definition and Relevance: Least Bell’s Vireos (LBVI) are a state and federally listed endangered species that nests exclusively in riparian areas in California. Conservation Science and Data Visualization and Aerial Information Systems co-developed a standardized mapping protocol, called VireoVegMap, with the objective of providing a comprehensive map of potential LBVI nesting habitat. Dominant vegetation map units and secondary map attributes were chosen to provide specific information relevant to LBVI ecology, conservation, and management. We then applied this protocol, using 2020 aerial imagery, to create a baseline map of riparian vegetation to support vireo recovery planning and status evaluation. Mapping of 2020 riparian vegetation establishes a baseline for range-wide LBVI nesting habitat conditions that can be used to: * Evaluate the range-wide status and distribution of riparian vegetation that LBVI may use for nesting. * Develop A _rundo donax_ (Giant Reed) removal strategies at the scale of HUC8 subbasins that will maintain or expand existing areas of native riparian vegetation nesting habitat. These areas, with follow-up management, will help LVBI reoccupy formerly suitable nesting habitat that has been lost to Arundo _._ * Understand the extent of the threat to riparian vegetation that is imposed by the emerging stressor of shot-hole borer invasion and develop potential management strategies. * Evaluate the potential impacts of groundwater management issues on vireo habitat across the species’ potential breeding range. * Evaluate the potential impacts of wastewater management issues on vireo habitat across the species’ potential breeding range. * Develop habitat-based management and restoration strategies. * Creation Method: The overall study area consists of twenty-eight USGS Hydrologic Unit Code (HUC) 8 subbasins in Central and Southern Coastal California and Southern California Deserts. This study area is represented by a polygon feature class in the project geodatabase called “Total Study Extent”. Within this large study area, a Focused Mapping Area was developed to ensure near-complete coverage of all riparian vegetation within active channels and floodplains of Level 1 stream networks (e.g., streams that terminate in the Pacific Ocean) within each HUC8 subbasin. Similar protocols were developed to cover active channels and floodplains of desert streams that flow eastward from Peninsular Ranges and terminate in playa lakes. Work was performed on the project between 2021 and 2023. Project data was produced applying heads-up digitizing techniques in an Esri ArcMap environment using 2020 National Agricultural Imagery Program (NAIP) imagery (60-centimeter base; true-color and color infrared). Ancillary imagery and data sources provided context during mapping. Original data are in vector format. Each original map polygon was assessed for 6 attributes: * Dominant vegetation map unit type (defined as the vegetation type with >50% relative cover, regardless of total percent vegetation). * Tree Willow Cover (absolute percent cover of all species of willow trees combined). This ensures that all mapped stands include information on this primary tree nesting habitat type for LBVI. * Shrub Willow/Mulefat Cover (absolute percent cover of all shrub willow species and mulefat, _Baccharis salicifolia_ ). This ensures that all mapped stands include information on this primary shrub nesting habitat type for LBVI. * Arundo Cover (absolute percent cover of _Arundo donax_ ). This ensures that all mapped stands include information on this invasive exotic species, which degrades LBVI habitat and in some cases, replaces it. * Tamarisk Cover (absolute percent cover of _Tamarix_ spp _.)._ This ensures that all mapped stands include information on this invasive exotic species. * Dieback Index (absolute percent cover of all trees and/or shrubs within a mapped polygon that show signs of dieback). This provides useful information about vegetation conditions and potential drought effects on vireo habitat. For all but one map unit, the minimum mapping unit (MMU) polygon size was 1 acre. Due to the importance of early detection of Arundo, in order to plan for its removal, smaller _Arundo donax_ stands were mapped, with polygons as small as a half-acre. Download link for the original vector data:[ https://drive.google.com/file/d/1mfwlqJq1upEPIQ1f3pVbrmOOyBNb31DV/view](https://drive.google.com/file/d/1mfwlqJq1upEPIQ1f3pVbrmOOyBNb31DV/view) Download link for the final report describing mapping methods and summarizing results:[ https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=215147](https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=215147) The original vector data were simplified to create a raster layer that represents Least Bell’s Vireo nesting habitat for the Southern and Central California Coast Regions by: 1 Including only the subset of polygons within these two geographic regions 2 Including only the subset of polygons that had >15% shrub willow/mulefat cover and/or >15% tree willow cover (primary characteristics of Least Bell’s Vireo nesting habitat). 3 Including only the subset of polygons at elevations less than 512 meters (LBVI rarely nest above this) 4 Rasterizing this subset of polygons on the VegName field (which represents the dominant classified vegetation type). Dominant riparian vegetation map units with Least Bell’s Vireo Habitat were, from highest to lowest acreage: Willow/Mulefat Shrub, Tree Willow, Cottonwood, Sycamore, Elderberry, Riparian Tamarisk, Riparian Oak, Riparian Alluvial Scrub, Alder, Post-fire disturbance, Post-disturbance (unknown cause), and Exotic Trees. * Credits: Lott, C.A., Reyes, E., A. Glass, and D. Johnson. 2023. A Range Wide Map of Least Bell's Vireo Nesting Vegetation: Mapping Protocol. Conservation Science and Data Visualization; Boise, ID; and Aerial Information Systems, Inc.; Redlands, CA.; 111pp. Available at:[ https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=215147](https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=215147)