Author: Hannah B. Manninen Publisher: ISBN: Category : Mule deer Languages : en Pages : 0
Book Description
Mule deer (Odocoileus hemionus) populations have declined throughout their range in the western United States since the 1980s. Habitat loss, overgrazing, disease, and predation contribute to the decline of mule deer populations. Navajo Nation, the largest federally recognized Indian tribe in the United States, encompassing 71,000 km2 in New Mexico, Arizona, and Utah, has experienced a 49% decline in mule deer over the past decade. Given knowledge of space use is an important component to recovery plans, my objectives were to (1) classify each deer as a migrant, resident, disperser, or nomad; (2) determine dates and durations of deer classified as migrants including means and ranges of spring and fall migration; (3) quantify distances traveled during spring and fall migration; (4) estimate sizes of seasonal home ranges and core ranges for migratory mule deer; and (5) develop resource selection functions. GPS collars were placed on 99 mule deer (79 F, 20 M) during 2018-2020. Movements were analyzed using net-squared displacement for individuals with >6 mo of data. Movement trajectories (n=108) from 67 unique mule deer were analyzed to determine whether they were migrants or non-migrants. An ANOVA was performed to determine whether sex, season (i.e., spring or fall), strategy (i.e., short-distance or long-distance migrant), or an interaction between migration duration and migration distance. Seasonal home ranges were defined using 95% kernel density estimates (KDE), and core ranges with 50% KDE. An ANOVA was performed to determine whether sex, migration strategy (i.e., short-distance or long-distance), or season (i.e., winter or summer) affected seasonal home range and core range size. I modeled third-order resource selection functions (RSF) following a use-availability design. Seventy-four percent (n=50) of mule deer were long-distance migrants, 18% (n=12) were short-distance migrants, and 6% (n=5) were non-migrants. Minimum, maximum, and mean distances traveled during migration were 2.6 km, 68.3 km, and 17.7 ± 1.1 km, respectively. Seasonal home ranges, core range, and resource selection were quantified for 84 (15 M, 69 F) trajectories from 63 mule deer. Mean female and male summer home ranges were 9.1 ± 11.1 km2 and 7.4 ± 6.6 km2, respectively, and mean female and male winter home ranges were 15.6 ± 21.5 km2 and 16.1 ± 7.5 km2, respectively. Season had a significant effect on home range size (F1,158=28.02, P
Author: Talesha Karish Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
White-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) occur in sympatric populations across the Great Plains in North America. Mule deer abundance and occupied range has been declining during the past three decades while white-tailed deer abundance and occupied range has been increasing. Factors contributing to the dichotomous population growth and distribution patterns across their sympatric range are unknown, but potentially include differential survival, space use, and resource selection, all of which may be contributing to indirect competition that may be negatively affecting mule deer populations. Overlap in resource use or space use between mule deer and white-tailed deer could be evidence of competition or competitive exclusion. Activity patterns could provide insights for temporal segregation or competition. Differential space use could allow these species to spatially segregate and co-occur without competing for the same resources. My objectives were to 1) estimate annual and seasonal survival rates, 2) identify cause-specific mortality of adult female mule deer and white-tailed deer, 3) compare behavior patterns between adult mule deer and white-tailed deer of both sexes at seasonal and fine temporal period scales, 4) evaluate the difference in movements between adult female mule deer and white-tailed deer at seasonal and fine temporal scales, 5) test for differences in home range area and composition of adult female mule deer and white-tailed deer at seasonal and fine temporal scales, and 6) evaluate differences in seasonal multi-scale resource selection by female mule deer and white-tailed deer in western Kansas. I deployed collars on 184 pregnant females (94 mule deer and 90 white-tailed deer) at two different study sites in western Kansas (North, South) over three years, 2018, 2019 and 2020. Each deer received a high-resolution GPS/VHF collar that recorded hourly locations, activity accelerometer data along 3 axes, and used an activity sensor to identify mortality events. I used a Kaplan-Meier model to estimate cumulative weekly and annual survival and fit a hazard function to each survival model. I tested for relative influence of factors on estimated survival. I categorized activity points into three behavioral states (feeding, resting, and running). I converted activity points into a proportion of total behavior for each deer and tested for differences in the proportion of behavior categories between species and among seasons. I calculated individual hourly and daily movements seasonally and compared them between species and among seasons. I calculated annual and seasonal 95% home ranges and 50% core areas for each individual deer using a Biased Brownian Bridge movement model. Using logistic regression, I modeled resource selection by mule deer and white-tailed deer at the landscape scale, within home range scale, and within the core home range to identify selection for potential habitat variables and cover types. There was no difference in annual survival of adult female deer between species (mule deer [0.78 ± 0.04] and white-tailed deer [0.77 ± 0.05]). Harvest was the leading known cause of female mortality at 14% of the total mortality, but it was low compared to other studies in the Great Plains. Behavior of both species was similar in all seasons except for rut for males. In rut, males doubled their running behavior. Firearm season produced no changes in behavior for either species or sex. However, the greatest movements and home ranges were in the firearm season. There were greater movements and home ranges in the cold seasons than in the warm seasons. Mule deer were found to use steeper slopes than white-tailed deer, and white-tailed deer used riparian and woodland areas more than mule deer. Habitat patches enrolled in the U.S. Department of Agriculture Conservation Reserve Program were strongly selected by both species in every season and scale. Managers should focus on preserving CRP to stabilize the mule deer population. Given harvest rates of females are low, survival of adult females of both species of deer appears to be little affected by harvest, so there is no need to alter harvest rates of either species.
Author: Mallory Sandoval Lambert Publisher: ISBN: Category : Mule deer Languages : en Pages : 108
Book Description
Human-induced rapid environmental change (HIREC) underlies the Anthropocene. One principal difference between present-day and historical environmental change is the pace and scale. Just 300 years ago, 95% of Earth’s ice-free land was considered wildlands or semi-natural. Today, almost ~55% of ice-free land has been converted for human uses. This poses a challenge for animals, who must move through landscapes to eat, mate, and escape from predators. Indeed, this rapid rate of landscape change has likely not been experienced by animals in their evolutionary past. Further, animals that rely on long-term memory of past environmental conditions are struggling to track environmental change. In this thesis, I examined two key gaps in knowledge in how animals respond to HIREC. First, I assessed how the movement mechanism (oriented versus memory-based) an animal employs influences its response to HIREC (Chapter 1). Second, I assessed how responses develop over time while HIREC is occurring (Chapter 2). I used long-term datasets from 183 collared mule deer (Odocoileus hemionus) and 89 pronghorn (Antilocapra americana) that migrate through and winter on a natural gas field in western Wyoming to carry out this work. Mule deer and pronghorn rely on memory-based movements during their up to 200 km migrations and on oriented movements while on their smaller and constrained winter ranges. Mule deer use strong spatial memory during migration and have extremely high fidelity to their migration routes. Pronghorn, in contrast, are more plastic and tend to change whether and where they migrate from year to year. We evaluated responses to surface disturbance (native habitat converted to roads and well pads) using habitat use and selection analyses across three spatial scales during winter and migration periods. While using memory-based movements during migration, both species were reluctant to abandon traditional migratory routes until a disturbance threshold was surpassed, after which they avoided HIREC. For pronghorn, thresholds ranged from 1-9% surface disturbance, whereas mule deer thresholds were consistently ~3%. In contrast to the migratory responses, both species avoided HIREC across a gradient of low-high amounts of HIREC while using oriented movements on winter range. Once these overall responses were established, I then assessed whether they changed or remained constant over time (Chapter 2). Animal populations may have immediate responses to HIREC or they may develop a response over time, resulting in a time-lag between the onset of HIREC and a population’s response. With immediate responses, it is likely that individual behavioral plasticity is the underlying mechanism of a population’s response to HIREC. For time lags, it is likely that natural selection acts on personalities within a given population. Using the mule deer dataset only, I fit resource selection functions (RSF) using a Generalized Additive Mixed Model (GAMM) to evaluate temporal trends in the behavioral response to the natural gas development during both migration and while on winter range. At the population level for both migration and winter range, mule deer exhibited a time-lag response to HIREC (i.e., natural gas development). During migration, during the first 8 years of this study, mule deer avoided development only after a threshold of development was surpassed and this threshold varied from year to year. Following the 8-year lag, mule deer consistently avoided development year to year once development surpassed a ~2% threshold. For winter range, during the first 9 years, mule deer responses to development varied year to year, although they mainly avoided development. Following the 9-year lag, the avoidance of development became stronger and more consistent. At the individual level for both migration and winter range, mule deer collared for > 1 year avoided development and their response to development did not change over subsequent years, suggesting little behavioral plasticity in this population. Overall, my work demonstrates that responses to HIREC by moving animals can be non-linear, are mediated by the movement mechanism animals are primarily relying on, and may not be consistent and strong until years after the onset of landscape change. Additionally, the disturbance thresholds identified herein for mule deer and pronghorn provide land and wildlife managers in western Wyoming with specific, actionable targets that can help to maintain the ecological function of migration routes and winter ranges. Energy development is, and will continue to be, a major source of disturbance for migratory ungulates, and other sagebrush obligate species, in western North America. An estimated 800,000 km2 of land is projected to be converted for energy extraction by the year 2040. Because this and other forms of land development will continue, it is increasingly important to understand how, when, to what degree, and over what time-scale animals respond to human disturbance so that potential impacts can be minimized.
Author: Rebekah A. Hellesto Publisher: ISBN: Category : Habitat selection Languages : en Pages : 0
Book Description
Converting wildlife habitat to agricultural monoculture is one of the greatest drivers of habitat loss and can be a severe threat to many wildlife species. However, because mule deer (Odocoileus hemionus) typically live in rugged, less arable landscapes, little is known about how they use habitat fragmented by agriculture. Using Global Positioning System (GPS) data from a partially migratory herd of 62 adult female mule deer from 2018-2022, we examined migration strategies and modeled habitat selection at three spatial scales in southeastern Washington, which is a mosaic of mostly privately owned cereal grain agriculture, shrubland, grassland, and restored cropland in the Conservation Reserve Program (CRP). A minority of the mule deer population was migratory (30%), with relatively short and fast migrations. During migration, they primarily selected for shrubland and grassland in both fall and spring. Mule deer used various components of the landscape throughout the year but selected grassland as their highest-ranked habitat year-round when selecting for home ranges within the study area (second order) and in winter when selecting habitat within their home ranges (third order). During summer, mule deer focused on shrubland and forested habitats within their home range, likely because it provided increased security and thermal cover for fawn-rearing. In the winter, they selected agricultural habitats to a greater degree, which might reflect the growing winter wheat (Triticum aestivum) providing more nutrition during that time. Survival from birth to recruitment into the adult population can greatly influence population dynamics of wild ungulates like mule deer and is affected by both nutrition and cover found in high-quality habitats. We used the GPS data from our population to create resource selection function models during parturition and early fawn-rearing and for fawn bed site characteristics (fourth order). We searched for fawns and fawn bed sites in 2021 and 2022 and used a parturition model to predict birthing events of collared females for which we were unable to find fawns in 2018-2022. For parturition, fawn-rearing habitat, and fawn bed sites, vegetation types that provided more vertical structure, including shrubs and trees, were consistently selected and agriculture avoided. Both intact (i.e., never plowed) shrubland and CRP shrubland were equally selected. These vegetation types provided vertical and horizontal concealment cover for fawns that were also important characteristics of fawn bed site selection. Our research suggests that to promote sustainable populations of mule deer in a landscape dominated by agriculture, managers and landowners could increase the prevalence of quality shrubs and trees where possible to improve habitat and continue support for the CRP program that provides economic incentive to restore croplands for the benefit of wildlife like mule deer.
Author: Hannah B. Manninen
Author: Kenneth J. Rodgers
Author: Richard M. Kerr
Author: Talesha Karish
Author: Woodrow L. Myers
Author: Woodrow L. Myers
Author: Elizabeth S. Bellantoni
Author: Tony G. Dickinson
Author: Mallory Sandoval Lambert
Author: Rebekah A. Hellesto