SDE Feature Class
Tags
elk, rocky mountain elk, Cervus canadensis, GPS, Brownian bridge movement model, migration mapper, stopover, winter range, telemetry, connectivity, California, Modoc, Siskiyou
Migration corridor, stopover, and winter range locations for Rocky Mountain elk (Cervus canadensis nelsoni) developed by the California Department of Fish and Wildlife (CDFW) for the Egg Lake herd, Modoc and Siskiyou counties, California. Corridors, stopovers, and winter ranges were developed in Migration Mapper with Brownian Bridge Movement Models using GPS locations from collared elk. Migration corridors represent movement routes used by elk between winter and summer range habitats. High use corridors were used by greater than or equal to 20% of the animals sampled. Migration stopovers and winter range polygons also represent high use areas.
The project leads for the collection of this data were Erin Zulliger and Richard Shinn. Elk (6 adult females, 3 juvenile [less than 1 year of age] males, and 2 juvenile females) were captured in 2017 and equipped with Lotek satellite GPS collars or VHF tags, transmitting data from 2017-2020. Additional GPS data was collected from elk (6 females) in 2001-2002 and included in the analysis to supplement the small sample size of the 2017-2020 dataset. The Egg Lake elk herd migrates from a winter range surrounding Egg Lake in Modoc County, California eastward into Siskiyou County for the summer. GPS locations were fixed at 4-hour intervals in the 2017-2020 dataset and 3 to 8-hour intervals in the 2001-2002 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 elk 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 winter ranges and the identification and prioritization of migration corridors. Brownian Bridge Movement Models (BBMMs; Sawyer et al. 2009) were constructed with GPS collar data from 11 migrating elk, including 22 migration sequences, location, date, time, and average location error as inputs in Migration Mapper. Nine migration sequences from 5 elk, with an average migration time of 6.78 days and an average migration distance of 26.83 km, were used from the 2000-2001 dataset. Fourteen migration sequences from 6 elk, with an average migration time of 7.79 days and an average migration distance of 42.40 km, were used from the 2017-2020 dataset. Corridors and stopovers were prioritized based on the number of animals moving through a particular area. 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 1400. Winter range analyses were based on data from 11 individual elk and 22 wintering sequences using a fixed motion variance of 1400. Winter range designations for this herd may expand with a larger sample, filling in some of the gaps between winter range polygons in the map. Large water bodies were clipped from the final outputs.
Corridors are visualized based on elk use per cell, with greater than or equal to 1 elk and greater than or equal to 3 elk (20% of the sample) representing migration corridors and high use corridors, respectively. Stopovers were calculated as the top 10 percent of the population level utilization distribution during migrations and can be interpreted as high use areas. Stopover polygon areas less than 20,000 m 2 were removed, but remaining small stopovers may be interpreted as short-term resting sites, likely based on a small concentration of points from an individual animal. Winter range is visualized as the 50 th percentile contour of the winter range utilization distribution.
Migration Mapper: https://migrationinitiative.org/content/migration-mapper Bjrneraas, K., Van Moorter, B., Rolandsen, C. M., and Herfindal, I. (2010). Screening global positioning system location data for errors using animal movement characteristics. The Journal of Wildlife Management, 74(6), 1361-1366. Sawyer, H., Kauffman, M. J., Nielson, R. M., and Horne, J. S. (2009). Identifying and prioritizing ungulate migration routes for landscapelevel conservation. Ecological Applications, 19(8), 2016-2025. California Department of Fish and Wildlife (CDFW)
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 Kristin Denryter, Erin Zulliger, or Richard Shinn 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 winter range utilization distributions and migration corridors from this herd, winter range for elk likely extends beyond the borders of what is considered winter range in our analysis, and likely does not represent the true extent of the winter range for this herd. Moreover, our sample only represents a small fraction of the possible population of elk migrating in this area; therefore, other corridors may have gone undetected in our analysis. This analysis represents migration corridors, stopovers, and winter range from one elk herd, one study, 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).
License: This work is licensed under Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ ). Using the citation standards recommended for BIOS datasets ( https://www.wildlife.ca.gov/Data/BIOS/Citing-BIOS ) satisfies the attribution requirements of this license.
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 | -122.027236 | East | -121.065698 |
North | 41.561283 | South | 41.193070 |
Maximum (zoomed in) | 1:5,000 |
Minimum (zoomed out) | 1:150,000,000 |
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 Kristin Denryter, Erin Zulliger, or Richard Shinn 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 winter range utilization distributions and migration corridors from this herd, winter range for elk likely extends beyond the borders of what is considered winter range in our analysis, and likely does not represent the true extent of the winter range for this herd. Moreover, our sample only represents a small fraction of the possible population of elk migrating in this area; therefore, other corridors may have gone undetected in our analysis. This analysis represents migration corridors, stopovers, and winter range from one elk herd, one study, 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).
License: This work is licensed under Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ ). Using the citation standards recommended for BIOS datasets ( https://www.wildlife.ca.gov/Data/BIOS/Citing-BIOS ) satisfies the attribution requirements of this license.
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.