SDE Feature Class
Tags
management area, Peirson's milk-vetch, Algodones Dunes, off-highway vehicle, environment, Imperial County, biota
The purpose of the monitoring program was to obtain population size and density (plants/ha) estimates of the three special status species and the percent cover of associated perennial vegetation in the management areas in which Peirson's milk-vetch is found. The BLM is confident that they captured the core distribution for Peirson's milk-vetch even though the precisions of the population estimates were below the 30% target. Perennial vegetation cover is not reported in this database.
In 2004, the Bureau of Land Management (BLM) implemented a monitoring program of three special status plants (Peirson's milk-vetch, Algodones Dunes sunflower, and sand food) and associated vegetation in the Algodones Dunes as part of the Imperial Sand Dunes Recreation Area (ISDRA) Management Plan. This data layer represents the presence of Peirson's milk-vetch in the study area. Peirson's milk-vetch (Astragalus magdalenae var. peirsonii) is found in seven of the eight designated management areas of the ISDRA. A sample of 135 belt transects, 25m wide and ranging from 2.35km to 14.16km long, were surveyed in the spring of 2004 in 12 sampling areas within the seven management areas in which Peirson's milk-vetch occurs. These sampling areas were positioned to encompass most of the Peirson's milk-vetch habitat in the Dunes. Data were recorded in contiguous 25m segments along each transect. These segments are called cells. A total of 37,169 cells were visited. Only the values for the occupied cells (represented in this data layer as points, each point being the southeast corner of an occupied cell) are included in this data layer. Counts were made of the total number of Peirson's milk-vetch plants, and were categorized based upon life stages (seedlings and young non-flowering plants, flowering plants, and plants over 1 year old). Precision of these estimates, calculated for each management area, ranged from 35% - 132%, probably due to the variation in the distribution of Pierson's milk-vetch in each management area. The number of plants with evidence of damage from off-highway vehicles and other sources was also noted. Detailed study methodology is described in Willoughby 2005a.
U.S. Bureau of Land Management, California State Office
For use by California Department of Fish and Wildlife (CDFW) staff and California Natural Diversity Database (CNDDB) subscribers. Due to the sensitive status of the species in this data, CDFW policy restricts its access.
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 | -115.315729 | East | -114.884022 |
| North | 33.134042 | South | 32.708813 |
| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |
For use by California Department of Fish and Wildlife (CDFW) staff and California Natural Diversity Database (CNDDB) subscribers. Due to the sensitive status of the species in this data, CDFW policy restricts its access.
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.