Elk Monitoring Summary

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Elk Monitoring Summary

August 1, 2013

Teagan Hayes shares a summary of elk population and location surveys to date. This update also introduces future directions for study.

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Elk Season Summary Fall Spring

100 elk graze near the forest edge and above the road near North Draw. April 1, 2013 Below: Two magpies eat insects on an unperturbed young elk. March 20, 2013

The largest herds of elk spend time in open grasslands and areas planted with forage grasses. These areas include cheatgrass, native grasses, and rhizomatous grasses like Kentucky bluegrass.

Year 1 elk observations: October 2011 – April 2012.

Year 2 elk observations: October 2012 – April 2013.

Spatial distribution of elk changes during hunting season, winter, and spring. These maps also reveal that elk use some areas all year, like the open grassland south of Tongue Creek.

A small herd of elk consistently used the west side of the Bitterroot valley. Observations from October to April clustered in a small area. The most use occurred in areas with the least development between Lolo and Florence.

Highway 93 and the Bitterroot River separate elk on the west side of the Bitterroot Valley from MPG. Movement between the herds is likely limited, but multiple elk mortalities still occur each year on the busy highway. The frequency of elk observations west of the river increased in 2012-13. Average elk herd size was 55 in 2012-13 and 62 in 2011-12.

Efficient wildlife monitoring requires accurate population estimates at specific times. Geography, field of view, and access time limit the usefulness of ground observations. Regular aerial monitoring records ungulates across the entire property at once, reduces the noise associated with ground-based observations, and opens a larger area for counting. Also, monitoring at the same time for each observation date reveals variation in group movement and habitat use. An iPad application for data entry could improve the accuracy of herd locations and numbers. This technology paired with aerial monitoring would record wildlife numbers and precise spatial distributions on detailed maps. This data would show plant community use and the spread of one group across different habitat types.

Pellet transects Current pellet surveys at point counts are limited to lower elevation areas of the ranch. Distance sampling using pellet transects can help estimate ungulate density and abundance across the property. Distance sampling surveys create a detection function to estimate the likelihood of pellet detection related to distance from the observer (Buckland et al. 1993). Pellet transects are useful for monitoring wildlife that are difficult to observe during surveys. MPG’s varied terrain makes observations difficult in draws, heavily forested areas, and higher elevations that are not accessible in winter. Additional pellet transects could be sampled after several years to show differences in ungulate use over time. This would prevent repeated disturbance at the same locations every year. Seed dispersal Elk are the most numerous large mammals that travel across this landscape. As they move, elk browse, graze, and deposit viable seeds and propagules. In this way, elk may introduce new species and genetic material to plant communities they visit. Seeds in elk scat samples from several habitat types could be planted in greenhouse trials. The species that germinate are likely candidate to be distributed through scat.


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01-07-13 Elk Monitoring Update

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Miller Creek Bat Survey