Telemetry Studies of Mountain Ungulates in the Greater Yellowstone Area
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GPS-VHF TELEMETRY STUDIES OF MOUNTAIN UNGULATES IN THE GREATER YELLOWSTONE AREA Introduction………………………………………………………………………………. 1 Capture and Instrumentation Methodology………………….………………………… 3 Dual Collar Strategy………………………………………..……………………… 3 Multiple Deployment Strategy……………………………..……………………… 9 Study Sites…………………………………………………………………..…....... 10 Capture Techniques………………………………………….…..………………… 19 Chemical Immobilization………………………………….…….………………… 24 Collaring Technique……………………………………………..………………… 26 Health and Disease Sampling…………………………………...…………………. 27 Biological Samples and Morphological Measures……...…………………. 27 Analysis of Biological Samples…………………………………………….29 Field Studies for Population Dynamics…………………………………………………. 30 Database Overview…………………………………………………….…………………. 31 Capture and Monitoring Database…………………………………………………. 32 Spatiotemporal GPS Database……………………………………………………... 33 Literature Cited…………………………………………………..………………………. 35 INTRODUCTION The greater Yellowstone area (GYA) embodies a variety of mountain ranges with diverse geology, topography, and climate regimes that result in differing ecological settings for the two mountain ungulates that occupy the region, bighorn sheep and mountain goats. Both species are important large mammals with high intrinsic value to the people occupying the region as well as the millions of visitors each year that come from throughout the world to enjoy the natural beauty and wildlife of this last relatively intact temperate ecosystem. Basic research to understand the ecology of these two prominent large mammals in the GYA have been quite limited compared to all the other large mammals that occupy the region, with most agency resources expended on routine population monitoring. The GYA Mountain Ungulate Research Project was initiated in fall 2009 with funding from Yellowstone National Park to begin filling this scientific void in order to inform policy and enhance management and conservation of these species. We have developed a strong collaboration with all the state and federal agencies responsible for wildlife and public land management in the mountainous regions of the GYA including the National Park Service (Yellowstone and Grand Teton NP), US Forest Service, Wyoming Game and Fish Department, Idaho Department of Fish and Game, and Montana Fish Wildlife and Parks, and have also received support from several non-government sportsman organizations and the Canon Corporation. 1 All of these organizations have varying and overlapping interest for initiating comparative telemetry studies of bighorn sheep and mountain goats in the region to address a myriad of important ecological questions. Basic ecological information is needed on population dynamics and vital rates (survival, reproduction) and the factors that influence annual variation in demographic performance. There is also a dearth of information on spatial ecology including seasonal distribution patterns, movement dynamics, and migration corridors. Better seasonal habitat models are also needed to inform policy on land use management and conservation, as well as to aid in identifying appropriate sites for restoration of native bighorn sheep. Little is known about metapopulation dynamics and the potential for genetic exchange and disease transmission. The region is also experiencing unprecedented climate warming that is predicted to have particularly strong impacts on alpine and subalpine species and communities. In addition, the presence and continued range expansion of non-native mountain goats that were introduced into some mountain ranges of Montana and Idaho between the late 1940s and early 1970s has generated an array of sites with varying levels of occupancy, both allopatric (one species) and sympatric (both species) with bighorn sheep populations. With mountain goat occupancy of sympatric sites across the GYA ranging from 5 to 60 years, a valuable and unique opportunity exists to collect information on competition and population dynamics for both mountain ungulates. The challenge, then, is to implement a large-scale study to sample across these various allopatric and sympatric sites while also capturing the varied environmental attributes that are present in mountain ungulate habitat across the GYA. The Mountain Ungulate Project, through significant collaborator effort and input, has selected several bighorn sheep and mountain goat herds throughout the mountain ranges of the GYA for the implementation of telemetry studies to gain ecological knowledge that will enhance conservation and management of these species by all the natural resource agencies with administrative authority in the region. To address these broad objectives, we intend to simultaneously collar individuals of both species in several sympatric herds as well as a number of allopatric herds. The sympatric herds selected will have varying durations of mountain goat occupancy, from areas where bighorn sheep ranges have only recently been colonized by mountain goats to areas where mountain goats have shared ranges with bighorn sheep for many decades. While this large-scale, multi-species, and multi-study site research plan is ambitious, we have strong support from our collaborators, have secured adequate resources to initiate our research plan, and have received encouragement from a number of organizations and individuals that additional funding may be secured as we continue to develop the research program and produce creditable and high quality scientific products. We are committed to make this research program successful and are confident that it will result in valuable ecological knowledge that will contribute substantially to the conservation of local and regional populations of both bighorn sheep and mountain goats throughout the GYA. 2 Our specific objectives include the collection of information on 1) population demographics and dynamics, 2) seasonal distributions, 3) movement dynamics, including pathways of genetic exchange and disease transmission, and 4) competition dynamics,. The fine spatial and temporal resolution data collected from these studies will also greatly expand and compliment the development of rigorous habitat models for both mountain ungulate species that are the focus of separate occupancy studies currently being initiated in many of the same areas. The purpose of this section is to provide a detailed description of the telemetry studies, including the methodology, study site and herd selection, capture operations, and database overview. We also report on the progress and status of current and planned telemetry study efforts. CAPTURE AND INSTRUMENTATION METHODOLOGY In order to collect information on mountain ungulate populations, demographic characteristics, competition, and movement dynamics, we have designed and begun to implement telemetry studies incorporating multiple study sites, dual collaring (2 types of collars on same animal) and multiple deployment (same collar deployed consecutively on different animals) strategies. This integrated research plan will maximize field and funding efficiencies and collection of both demographic and spatial data. If we can maintain the strong collaborations that have been built during the first few years of this initiative and broaden our funding base, we are confident that this large-scale long-term research plan will provide important ecological insights for both bighorn sheep and mountain goats that will significantly enhance conservation and management of these iconic mountain ungulates. The methodology for this strategy is outlined here. DUAL COLLAR STRATEGY The dual collaring strategy involves the deployment of both a GPS and VHF radio collar on a single individual. The advantage of GPS technology is that it provides fine-scale (precise) spatial data at regular, relatively short, time intervals. Such data are optimal for addressing questions of spatial ecology. Spatial studies will provide insights into movement dynamics at the scale of individuals important in defining discrete populations, identifying migration pathways and corridors, and describing patterns of fidelity, dispersal, and metapopulation dynamics. GPS technology is the most appropriate method for this effort as detailed spatial studies would require intensive and extensive aerial surveys if VHF telemetry were used. The unpredictability of flying weather and the inherent hazards of flying in mountainous terrain would limit both the spatial and temporal resolution of the data and, thus, erode the potential ecological insights that can be gained from such an effort. The disadvantage, however, of GPS technology is that deployment on animals is limited to approximately 1 to 2 years due to short battery life which limits their utility for collecting demographic (survival, reproduction) data. The VHF collars, on the other hand, have the capacity for long term deployment (about 5-8 years) and are optimal for addressing questions of 3 population dynamics. Understanding and estimating the basic vital rates of the populations, that is survival and reproduction of adults and survival and recruitment of young-of-the-year, is important knowledge for managing and conserving populations. In ungulates, these demographic processes are age-dependent and can vary from year-to-year depending on variability in warm and cold season weather which, in turn, influences forage quantity, quality, and availability. VHF telemetry is a simple, reliable, and economical tool for long term survival and reproduction studies of individual animals. Thus, the combined instrumentation