Pronghorn Home Range - Mount Dome - 2019-2020 [ds2935]

The project lead for the collection of this data was Richard Shinn. Pronghorn (9 adult females) were captured and equipped with GPS collars (Sirtrack, Havelock North, NZ) transmitting data from 2019-2020. The Mount Dome herd contains short distance, elevation-based migrants, but this herd does not migrate between traditional summer and winter seasonal ranges. Instead, much of the herd displays a somewhat nomadic migratory tendency, slowly moving up or down elevational gradients. Some individuals used higher elevation areas throughout the summer, though this pattern was not ubiquitous. Therefore, annual home ranges were modeled using year-round data to demarcate high use areas in lieu of modeling the specific winter ranges commonly seen in other ungulate analyses in California. The plateau extending south of Sardine Flat is highly used during winter by many of the collared animals, while the higher elevation flatlands between Klamath Lake Sump and Mount Dome are used in summer. Overall, a much smaller area is used than adjacent pronghorn herds in California, with much of the full home range extent being high use. GPS locations were fixed between 1-2 hour intervals in the dataset. To improve the quality of the data set as per Bjrneraas et al. (2010), the GPS data were filtered prior to analysis to remove locations which were: i) further from either the previous point or subsequent point than an individual pronghorn is able to travel in the elapsed time, ii) forming spikes in the movement trajectory based on outgoing and incoming speeds and turning angles sharper than a predefined threshold , or iii) fixed in 2D space and visually assessed as a bad fix by the analyst.

The methodology used for this migration analysis allowed for the mapping of the herds home range. Brownian bridge movement models (BBMMs; Sawyer et al. 2009) were constructed with GPS collar data from 9 pronghorn, including 12 migration sequences, location, date, time, and average location error as inputs in Migration Mapper. BBMMs were produced at a spatial resolution of 50 m using a sequential fix interval of less than 27 hours and a fixed motion variance of 1000. Large water bodies were clipped from the final outputs. Home range is visualized as the 50 th percentile contour (high use) and the 99 th percentile contour of the year-round utilization distribution. Twelve years of collective movement data from 9 individuals were used to construct home ranges. Home range designations for this herd may expand with a larger sample.

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.

The user accepts sole responsibility for the correct interpretation of this report and the correct use of its accompanying dataset. Prior to using this dataset, please contact Richard Shinn, Kristin Denryter, or Christine Found-Jackson to ensure correct interpretation of the data. The data is best interpreted at a scale of 1:100,000 or larger. Given the small sample size used to construct home range utilization distributions from this population, the home range of these pronghorn likely extends beyond the borders of what is considered high-use home range in our analysis, and likely does not represent the true extent of the home range for this population. This analysis represents home range from one pronghorn population, and is one of a suite of datasets being developed for Californias ungulate herds by CDFW.

CDFW makes no warranty of any kind regarding these data, express or implied. By downloading these datasets, the user understands that these data are subject to change at any time as new information becomes available. The user will not seek to hold the State or the Department liable under any circumstances for any damages with respect to any claim by the user or any third party on account of or arising from the use of data or maps. CDFW reserves the right to modify or replace these datasets without notification. No statement or dataset shall by itself be considered an official response from a state agency regarding impacts to wildlife resulting from a management action subject to the California Environmental Quality Act (CEQA).