Recipient Organization
UNIVERSITY OF NEVADA
(N/A)
RENO,NV 89557
Performing Department
Natural Resources & Environmental Sciences
Non Technical Summary
Mule deer (Odocoileus hemionus) occupy a variety of habitats throughout western North America and require relatively large areas to assure persistence of viable populations, especially in the Chihuahuan, Sonoran, Mojave, and Great Basin deserts. Mule deer are dependent upon resources, including water and forage, adequate to meet the demands of growth, reproduction, and lactation. Resources that often are assessed to determine the distribution of desert mule deer are availability of forage, nutritional quality of forage, cover, mating sites, natal sites, and availability of water. In arid regions, mule deer are dependent on free water, and often are located close to sources of water, particularly during dry seasons. Indeed, physiological demands may dictate that during times of water scarcity, ungulates remain close to water rather than ranging widely to forage. Mule deer in the Sonoran Desert tended to remain close to sources of water during the hot-dry season when
water was most scarce, a common occurrence in the southwestern United States. Moreover, water developments in Arizona received heavy use by desert mule deer, primarily during hot summer months. Thus, distribution, abundance, and seasonal availability of water affect the distribution of mule deer across the landscape. The longer that water sources remain available the more use they receive by mule deer and other species of wildlife.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
The purpose of this investigation is to assess responses of mule deer inhabiting the eastern Mojave Desert to the provision of water at locations where it had been, but is no longer available. Secondarily, we address interactions between mule deer and vegetation as influenced by availability of surface water. This project will test 4 hypotheses. H1: Provision of permanent, year around water will be beneficial to mule deer populations. H2: Provision of water at historic wells will not be detrimental to habitat for other wildlife species. H3: Availability and quality of forage for mule deer and other species will be greatest in areas around developed water, seeps, and springs than away from sources of water or water catchments that are not functional. H4: Mule deer will actively select for areas near permanent sources of water and home range size of mule deer will be smaller in areas with permanently available water.
Project Methods
Assessment of hypothesis 1 will entail capturing 30 female and 10 male mule deer in the area which has permanent water available including developed springs and wells reinstated by NPS and 30 female and 10 male mule deer in areas without permanent, developed water sources. Capture effort will be concentrated on female mule deer, and males will be equipped with radio collars opportunistically. Individuals will be captured either using net guns from a helicopter or clover traps placed near water sources. All individuals will be eartagged to obtain individual marks, fitted with a small standard VHF transmitter, and a subsample of individual females will be equipped with additional GPS radio collars to record their locations up to 7 times/day. VHF collars on animals equipped with GPS collars will remain on the individual after the GPS collar drops off of the animal. For hypothesis 2,we will monitor vegetation to assess potential impacts of increased wildlife use areas near
permanent water (developed springs and wells). Shrub cover will be estimated for each transect using the line intercept method, annually. Treatment and control sites will be compared using a repeated measures design, with specific locations treated as random effects. Differences between treatment and control sites for shrub cover will be interpreted as evidence for an impact on shrub habitat. For hypothesis 3,we will sample biomass of forbs and shrubs 2 times per year (spring-wet and summer-dry season) at locations of treatment sites (permanent water) and control (wells not reinstated) and random sites located a minimum distance of 250 m from known site.Treatment and random sites will be compared using a repeated measures design, with specific locations treated as random effects. Differences between treatment and control sites in trend for shrub cover will be interpreted as evidence for an impact on shrub habitat. For hypothesis 4, we will use locations in combination with a GIS
database maintained by the National Park Service. We will obtain random locations in each of the study areas and compare variables such as vegetation type, slope, aspect, elevation, distance to permanent water, distance to developed and undeveloped springs, in locations randomly selected from the GIS database to locations obtained from mule deer in each study area. Random locations will be used to characterize availability of habitats and locations of mule deer will characterize those used by mule deer.