In 2009, AGFD Research Branch completed a 3-year study
of Kaibab mule deer and winter range condition. One recommendation of that study was to develop a more comprehensive winter range monitoring approach which included multiple browse species and allowed measurement of trends in habitat quality over time. In Fall 2009, the Department initiated a 2-3 year effort, developing and testing new methods to monitor browse condition and use by wintering mule deer on the western portion of the Kaibab Plateau
We are conducting our study in northwestern Arizona on the Kaibab Plateau in GMU 12A-West. The study area ranges in elevation from 4,921 to 6,890 feet and is a mix of pinyon-juniper woodland and shrublands dominated by sagebrush, cliffrose, Mormon tea, and Rabbitbrush.
We will use browse and other vegetation data collected 2006-2008 to select a subset of permanent plots that best represent habitat conditions across the 12A-W winter range. We will also work with AGFD field personnel to identify portions of the winter range where additional sampling plots may be needed. Each plot will be permanently marked and located with GPS coordinates and sampled twice per year (Spring and Fall). At each plot, we will place 1 or more 50-100 m transects, on which we will sample woody browse and herbaceous understory vegetation. Browse plants will be classified with respect to species, age, vigor, and availability to deer. These data will be used to rate range quality on each plot and across the 12A-W winter range.
Each Fall, we will collect current annual growth samples from sagebrush and cliffrose, the 2 primary browse species in Kaibab deer winter diets. Our target sample size is 100 leaders from each. We will measure length, basal diameter, and tip diameter of each leader, to determine if these browse species exhibit consistent length-diameter relationships that can be used to estimate use from spring-only twig diameter measurements. We will also mark and measure 4 unbrowsed leaders on 50 sagebrush and 50 cliffrose plants.
We will collect browse use measurements immediately after deer depart the winter range. We will re-measure marked cliffrose and sagebrush leaders and directly estimate use from the proportion of material removed. If the twig-diameter method is viable for either or both species, we will also collect those measurements from the marked plants. We will also measure additional, unmarked leaders on cliffrose plants, and compare overall remnant leader length to browse use guidelines developed in previous studies.
The results of the study will help determine what type of long term monitoring strategies will be most effective to monitor overall browse condition on unit 12A-W.
For more information
Larisa Harding, Arizona Game and Fish Department
5000 W. Carefree Highway, Phoenix, AZ 85086-5000.
Phone: (623) 236-7301, E-mail: Lharding@azgfd.gov