File Geodatabase Feature Class
Tags
Habitat Mapping, Recovery Planning, Least Bells Vireo, Central California, Southern California, California Desert, Vegetation Classification, Aerial Photography Interpretation, Riparian Vegetation, Endangered Species
Least Bells Vireos (LBVI) are a state and federally listed endangered species that nests exclusively in riparian areas in California. Despite being listed for ~40 years, there has never been a single map, with high thematic resolution, of riparian vegetation covering the entire breeding range of this species. 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. Vegetation classification does not conform to Survey of California Vegetation standards and is not based in the National Vegetation Classification System. To meet the objective of mapping potential LBVI nesting habitat, a more vireo-centric mapping classification was developed for the VireoVegMap protocol . Stand classification criteria for VireoVegMap used straight dominance as the primary criteria for delineation of map units. More information is available from the report: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=215147
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. 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. Each map polygon was assessed for 6 attributes:
1. Dominant vegetation map unit type (defined as the vegetation type with >50% relative cover, regardless of total percent vegetation) .
2. 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.
3. 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.
4. 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.
5. Tamarisk Cover (absolute percent cover of Tamarix spp .). This ensures that all mapped stands include information on this invasive exotic species.
6. 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 condition 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 importance of early detection of Arundo, in order to plan for its removal, smaller Arundo donaxstands were mapped with polygons as small as a half-acre.
This dataset was produced by Conservation Science and Data Visualization and Aerial Information Systems
Disclaimer : The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.
Extent
| West | -121.947238 | East | -115.598473 |
| North | 37.162897 | South | 32.495270 |
| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |
Disclaimer : The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.