The West Tavaputs Plateau on the Nine Mile Range Creek unit is one of the few places in Utah where large acreages of summer range have been treated to mitigate fire risk and improve habitat for wildlife. This unit is very similar to the Book Cliffs and many mountain ranges in southern Utah where there is a narrow belt of high-quality summer habitat and abundant winter range, which is unlikely be limiting. Mule deer (Odocoileus hemionus) populations on this plateau are well below population objectives and have shown minimal growth in recent years. Potential explanations for this lack of growth may include intraspecific competition, drought and associated poor nutrition, predation, and degradation or fragmentation of habitat (Pojar and Bowden 2004, Bishop et al. 2005, Harrington and Conover 2007, Lomas and Bender 2007). Additionally, the narrow band of summer habitat atop the West Tavaputs Plateau has a complex predator community with assumed high density. It has been well documented that complex, high-density communities of predators can limit population growth, especially when populations are well below carrying capacity (Ballard et al. 2001, Laundre et al. 2006, Griffin et al. 2011). This unit has chronically low fawn/doe ratios during post-hunt classifications in November, but the putative cause (habitat limitations and poor condition versus predation) is unclear. The West Tavaputs Plateau is primarily private land. Most landowners on the Plateau have active habitat enhancement programs aimed at improving summer habitat for mule deer and other wildlife species. Two primary methods have been used to improve summer habitat. The first method includes using heavy equipment and a chain along with a large cylinder (to elevate the chain) to reset succession in mature and decadent stands of Englemann Spruce (Picea englemannii) and Subapline fir (Abies labiocarpa) to restore aspen stands and improve forb abundance. A second method includes mimicking wet meadow habitat by creating mosaics in high elevation Mountain sagebrush (Artemisia tridentate vaseyana) stands by mechanically chopping, discing, or harrowing methods. Initial evaluation of the vegetation response to these treatments is promising with strong regrowth of aspen observed. Given the focus by these private landowners on restoration of summer range at high elevations, this unit provides a unique opportunity to assess the value of summer habitat treatments on condition, production, and survival of mule deer in a control-treatment design.

The objectives of this project are to evaluate habitat selection and condition of adult female mule deer in relation to summer habitat treatments and then to monitor marked animals to understand how treatments influence selection of parturition sites, weight of neonates, growth rate of neonates to 6-months old, and survival of neonates during the initial months after parturition. The monitoring area lends itself to a control-treatment design where we can monitor the response (adult condition; habitat selection; weight of neonates; survival) of mule deer in treated areas and compare those metrics to mule deer using areas of similar elevation and habitat type that have not yet been treated.

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The mule deer management has a strategy to implement research projects on populations that are chronically below objectively. Additionally, it is of great importance to understand which habitats are of the greatest importance for mule deer and when the use of those projects provides the greatest benefit.

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To determine the effects of summer habitat treatment projects on nutritional condition of adult mule deer, we will capture adult deer in both spring and fall across the West Tavaputs Plateau to estimate condition. Some initial summer capture will likely be necessary to determine migration patterns and identify which animals are using treatments. We will measure condition of mule deer by estimating percent ingesta-free body fat (IFBF) based on a proven combination of palpation and ultrasonography measures (Cook et al. 2007). This metric has been collected on multiple units around the state and comparison of initial measurements of IFBF for mule deer on the Nine Mile, Range Creek unit with units from similar latitude will build understanding of the limiting factors affecting this mule deer herd. We will fit each captured individual mule deer with a GPS collars to identify preferences in habitat selection related to restoration areas, determine space-use and migratory patterns, estimate survival, and determine probable causes of death. GPS collars will collect a location every 2 hours providing a robust data set to use in a resource selection framework (RSF) to evaluate relative seasonal and annual selection for habitat types across the entire study area at both 2nd and 3rd order selection scales (Johnson 1980). These selection coefficients can then be used as predictors of IFBF at the individual animal level in addition to mean comparisons between control and treatment areas. By recovering deceased animals within 48 hours of a mortality signal, these collars will also enable us to determine survival and cause-specific mortality. We will use model selection and either known-fate models in Program MARK (White and Burnham 1999) or Cox proportional hazards models to estimate seasonal and annual survival rates and examine the influence of body condition (see below), use of summer habitat treatments, movement patterns, and environmental conditions on these rates. To examine herd production and recruitment, we will determine pregnancy rates and survival of neonate animals. During the February and March captures, all pregnant adults will be fitted with vaginal implant transmitters (VITs; Bishop et al. 2007). These VITs will allow us to capture and collar neonates in spring to estimate survival, recruitment, and cause-specific mortality of this under-studied age class. Neonate deer collars will last for 6-8 months and then a sample of 6-month old fawns will be recaptured and fitted with a GPS collar to measure growth (body mass at 6 months -- body mass at birth) and survival from 6 months to 1.5 years of age. This project will be initiated in fiscal year 2023 and will be completed in fiscal year 2025. Most captures will be conducted by the UDWR contracted capture company using standard net-gunning techniques. There may be a need for some summer/fall darting of deer by ground crews. Once a deer is captured, the capture company will transport it back to a staging area for processing by UDWR employees/volunteers. Data collected from the animal will include age, sex, various body measurements, blood samples, reproductive condition, and body condition (Cook et al. 2010).

Animals will be monitored using satellite GPS collars

This project will be a partnership between UDWR, BYU, conservation organizations, and private landowners.

This project will help identify the influence of summer range habitat treatments on mule deer, which may help improve future implementation of habitat treatment projects and mule deer management.

This project will help identify the influence of summer range habitat treatments on mule deer, which may help improve future implementation of habitat treatment projects and mule deer management.

07/01/2023

06/30/2024

2024

We captured 80 deer in December on the Range Creek Unit to assess condition and monitor overwinter survival. We captured an additional 64 deer in March 2024 to examine overwinter condition decline and check pregnancy. For 60 of the pregnant does, we inserted VITs to aid in neonate capture. In June, we captured 56 deer neonates to monitor survival and cause of death. Data will be analyzed based on use and selection for summer treatment projects to determine potential impacts on mule deer adults and fawns.

As we continue to monitor mule deer condition across Utah, the importance of body condition entering winter is becoming more apparent. As such, the importance of summer habitat for mule deer is also becoming clearer. On the Range Creek Unit, much work has been conducted to improve summer habitat for mule deer, which provides an excellent opportunity to assess if and how these treatments may benefit mule deer. The objectives of this project are to evaluate habitat selection and condition of adult female mule deer in relation to summer habitat treatments and then to monitor marked animals to understand how treatments influence selection of parturition sites, weight of neonates, growth rate of neonates to 6-months old, and survival of neonates during the initial months after parturition. The monitoring area lends itself to a control-treatment design where we can monitor the response (adult condition; habitat selection; weight of neonates; survival) of mule deer in treated areas and compare those metrics to mule deer using areas of similar elevation and habitat type that have not yet been treated.

Deer will continue to be monitored with GPS collars. This project will provide a better understanding the impacts of summer habitat treatment use on mule deer condition entering winter.