Joshua tree is a visually distinctive plant found in California''s Mojave Desert and adjacent areas. The unique silhouette and tall stature of Joshua tree relative to typical surrounding vegetation make it one of the most recognizable native plants of California deserts. There are two species of Joshua tree in California, western Joshua Tree (Yucca brevifolia) and eastern Joshua tree (Yucca jaegeriana). Eastern Joshua tree (Yucca brevifolia ssp. jaegeriana) distribution is represented in the data incidentally, but the primary purpose of this dataset is to illustrate the distribution of western Joshua tree. Western Joshua tree is distributed in discontinuous populations in the Mojave Desert and in a portion of the Great Basin Desert. Western Joshua tree is often noted as being abundant near the borders of the Mojave Desert in transition zones. No attempt was made to map Joshua tree distribution outside of California, and therefore the data are limited to geographic areas within California. CDFW possesses vegetation maps that cover a large portion of the California deserts where Joshua tree generally occurs. CDFWs Vegetation Classification and Mapping Program (VegCAMP) uses a combination of aerial imagery and fieldwork to delineate polygons with similar vegetation and to categorize the polygons into vegetation types. In 2013, an effort was made to create a vegetation map that covers a large portion of the California deserts. The vegetation data from this project includes percent absolute cover of Joshua tree and in some instances only Joshua tree presence and absence data. Western Joshua tree and eastern Joshua tree were lumped together as one species in these vegetation maps. A rigorous accuracy assessment of Joshua tree woodland vegetation alliance was performed using field collected data and it was determined to be mapped with approximately 95 percent accuracy. This means that approximately 95 percent of field-verified, polygons mapped as Joshua tree woodland alliance were mapped correctly. While Joshua tree woodland alliance requires even cover of Joshua tree at greater than or equal to 1 percent, the vegetation dataset has polygons recorded with less than 1 percent cover of Joshua tree as well as simple presence and absence data. The CDFW used Joshua tree polygons from vegetation mapping combined with additional point data from other sources including herbarium records, Calflora, and iNaturalist to create the western Joshua tree range boundary used in the March 2022 Status Review of Western Joshua Tree. CDFW reviewed publicly available point observations that appeared to be geographic outliers to ensure that incorrectly mapped and erroneous observations did not substantially expand the presumed range of the species. In a limited region, hand digitized points were used where obvious Joshua tree occurrences that had not been mapped elsewhere were present on aerial photographs. Creating a range map with incomplete presence data can sometimes be misleading because the absence of data does not necessarily mean the absence of the species. Some of the observations used to produce the range map may also be old, particularly if they are based on herbarium records, and trees may no longer be present in some locations. Additionally, different buffer distances around data points can yield wildly different results for occupied areas. To create the the western Joshua tree range boundary used in the March 2022 Status Review of Western Joshua Tree, CDFW buffered presence locations, but did not use a specific buffer value, and instead used the data described above in a geographic information system exercise to extend the range polygons to closely follow known occurrence boundaries while eliminating small gaps between them.

The 17,158 acre Johnson Valley project area is located in San Bernardino County, 32 miles east of Victorville, CA bisected by highway 247. The fine-scale vegetation map was created as part of a collaborative project between the United States Geological Survey (USGS) and the Vegetation Classification and Mapping Program of the California Department of Fish and Wildlife (CDFW) to show the correlation between vegetation and geomorphology. The vegetation mapping types are based on the vegetation classification that was developed for the larger Desert Renewable Energy Conservation Plan (DRECP) mapping project (CDFW 2013). The vegetation classification was developed using a compilation of data collected for several projects including Anza-Borrego Desert State Park and Environs (Keeler-Wolf et al. 1998), the Mojave Desert Ecosystem Program''s Vegetation Database (Thomas et al. 2004), Vegetation of Joshua Tree National Park (La Doux et al. 2013), and Vegetation Classification and Mapping at Lake Mead National Recreation Area, Mojave National Preserve and Death Valley National Park (in progress, draft as of 2014).

The Colorado Desert study area covers approximately 11,000 square miles (28,500 km. sq.) of which over two-thirds is managed by the Bureau of Land Management. The land is divided among the Imperial, Santa Rosa, Orocopia, Twentynine Palms, Bristol/Cadiz, Palen, Turtle Mountain, Whipple Mountain, Big Maria and Picacho planning units, which together will be referred to here as the Colorado Desert planning units.

The area is bounded on the north by Interstate 40. Its southern boundary is the United States/Mexican border, and its eastern boundary is the Colorado River and its delta lands. The western boundary is a winding line defined by the Twentynine Palms Marine Corps Base, Joshua Tree National Monument, the San Bernardino National Forest and the path of the Coachella and East Highland canals.

The Colorado Desert planning units are almost entirely in the low, hot desert below 2000 feet (610 m.). It is one of the harshest and most arid environments in North America. The interior of the Colorado Desert planning units is among the most sparsely settled in the United States.

This overview pulls together existing data relating to the cultural resources of the Imperial, Santa Rosa, Orocopia, Twenty-Nine Palms, Bristol/Cadiz, Palen, Turtle Mountain, Whipple Mountain, Big Maria, and Picacho planning units of the Colorado Desert. The goals here are a description and evaluation of these resources that may serve as a basis for cultural resource recommendations and, in turn, for an educated and enlightened management of these resources.

The cultural resources have been presented in terms of the chronological sequences, quality of collections and special studies. These cultural resources are presented against a background of environmental conditions of the Colorado Desert. The primary direction of the study was to outline the cultural resources in terms of man's use of the desert from prehistoric times through the ethnographic present to European occupation of the area. Most of the data relevant to the relationship of man to past environment are still to be recovered through archaeological, ethnohistoric, and historical fieldwork and analysis. Areas of greatest intensity of cultural activities have been identified for some periods. Land use in limited areas for short periods of time has been defined and the major direction in historical developments have been outlined. The paucity of data, however, makes it impossible to identify with certainty the systemic relationships of the all too often isolated fragments that make up the cultural resources of the Colorado Desert.

Originally the information in this record was migrated into tDAR from the National Archaeological Database Reports Module (NADB-R) and updated. In 2014, as part of its effort to improve tDAR content, the Center for Digital Antiquity uploaded a copy of the document and further improved the record metadata.

The University of California Riverside’s Center for Conservation Biology (CCB) has created fine-scale vegetation maps for a number of Conservation Areas under the jurisdiction of the Coachella Valley Multiple Species Habitat Conservation Plan (CVMSHCP) under contract with the Coachella Valley Conservation Commission (CVCC). The primary purpose for creating these maps is provide a landscape-scale approach to monitoring changes due to land use, invasive species, recreation, hydrology, and climate. These digital maps, documenting changes and their causes, are then tools for prioritizing future conservation actions. The vegetation classification follows Federal Geographic Data Committee (FGDC) and National Vegetation Classification Standards (NVCS; Federal Geographic Data Committee 2008). The classification is meant to align with previous and concurrent efforts previous survey and classification work done by California Department of Fish and Wildlife's Vegetation Classification and Mapping Program (VegCaMP) and Aerial Information Systems (AIS) for the Desert Renewable Energy Conservation Plan Area as well as the southeastern Salton Sea Mid-Desert Area, and by the National Park Service for Joshua Tree National Park.This unit was mapped using the California Department of Fish and Wildlife (CDFW) and California Natural Plant Society Combined (CNPS) Vegetation Classification and Mapping Program protocol (CNPS 2014). The primary purpose was to develop a dynamic and accurate vegetation map for the Coachella Valley Floor Reserve Management Unit, so that it may be applied to further conservation efforts and assist with management of the 27 species and 27 natural communities listed within the plan. Map polygons were assessed for vegetation type, percent cover, presence of exotics, anthropogenic disturbance, and roadedness. This map is an updated map for the year 2018 for the area within the 95,000 acres that fall within the 18 CVMSHCP Management Units on the Coachella “Valley Floor.” Within the study areas, rapid assessment protocol vegetation plots, basic vegetation assessment plots and supplemental reconnaissance observations were obtained within the study at pre-determined points in order to document the plant community, disturbances, and invasive species across space and types. Heads-up photo-interpretation of 2013 local flight true-color imagery and field information were combined to produce delineations of vegetation alliances and associations according to the California Department of Fish and Wildlife classification system, outlined in the Manual of California Vegetation (MCV) Second Edition (Sawyer et al.2009). Additional field data was collected in 2018 and incorporated into the 2018 map update. The 2018 map delineation was done by photo-interpretation of updated imagery, with a focus on stand changes, mortality, cover and land use changes, and other anthropogenic changes.To better focus on conservation of particular habitats, there are several alliances where the minimum mapping unit (MMU) is less than an acre; including Prosopis glandulosaWoodland Alliance (MMU .5 acres), and Washingtonia fillifera Shrubland Alliance(MMU .34 acres), as well as wetlands and certain wash types which displayed complexity that would necessitate delineation. In order to better delineate habitat for the aeolian suite of species covered under the Plan, the following provisional alliances were used: Dicoria canescens--Oenothera deltoides Sparsely Vegetated Active Dune Provisional Alliance; Larrea tridentata / Abronia villosa Stabilized Sand Fields Provisional Alliance; andPsorothamnus arboresens / Dicoria canescens Ephemeral Sand Fields Provisional Alliance.