Q: What is the Adaptive Harvest Management Plan for Mule Deer?
The Adaptive Harvest Management Plan for Mule Deer guides mule deer management in Montana, linking annual mule deer habitat conditions, population surveys and harvest information to set annual hunting regulations that are in sync with the species and how it is doing in a particular location.
Q: What is the basis for Adaptive Harvest Management in Montana?
Research on mule deer populations and habitats began in the mid-1970s with an unexpected decline in mule deer populations in the western states. Researchers initiated mule deer population studies in the Bridger Mountains of southwest Montana, in the Missouri River Breaks of north-central Montana and in the prairie-badlands along Cherry Creek in the southeastern part of the state to learn what factors influence the number of mule deer from year-to-year. Today with more than 25 years of research on mule deer, this work is one of the most comprehensive studies of a big game species ever compiled in North America.
Another mule deer population decline in the mid-1990s focused attention on the task of integrating the knowledge gained in the past 25 years into a systematic deer management strategy that can be applied consistently across the state. This is the work underway today.
Q. How often does FWP conduct mule deer surveys and why?
Annual surveys of Montana mule deer populations conducted by Montana Fish, Wildlife & Parks biologists contribute to Montanas valuable information base on mule deer population trends, use of habitat and social structure.
Q. How is the survey information used by FWP?
Today this information is the basis of Montanas mule deer management plan, called Adaptive Harvest Management. FWP biologists use the annual survey information when recommending hunting quotas and regulations and in managing mule deer populations. The goal of mule deer management is to help mule deer populations stay at or close to the average populations observed over the long-term in each type of mule deer habitat in the state.
Q. How are the survey's conducted and where?
FWP biologists conduct aerial surveys in 13 census areas. In census areas spring surveys are flown three times to increase accuracy. Winter flights are flown once. The 13 census areas, because of the important role they play in the research, require extra time to collect accurate and consistent data. In the 67 trend areas, spring and winter surveys are flown once. Trend areas provide supplemental information to help fill in the population picture across large geographic areas. A map of the survey areas is available at http://www.fwp.state.mt.us/hunting/ahm/mdpmu.gif.
Q. What do the surveys tell about future hunting opportunities and trends in populations?
Low fawn survival during the winter period will result in fewer yearling deer moving into the spring population. If this is a one-year event, fewer yearling bucks will be available during that fall's hunting season. If these conditions persist for several years, the number of bucks moving into the older age classes will decline, as will the number of does that become part of the core breeding population.
Q. When are the survey's conducted?
The winter or post-hunting season flights are flown in December and January and the number of bucks, does and fawns are tallied at that time. Spring flights from March 15 to April 30 reveal the number of fawns that survived winter, the number of fawns per 100 adults, and the total number of mule deer.
Q. When did FWP begin this formal process of collecting information on mule deer in Montana?
Research on mule deer populations and habitats began in Montana in the mid- 1970's in some areas and in the 1980's in others.
Q: How many different mule deer habitats are there in Montana?
Five different types of mule deer habitat can be found in Montana each with unique weather patterns, vegetation, topography, and deer population characteristics. Mule deer management is organized around these five different types of habitat. Population objectives set for each habitat take into account the natural volatility of mule deer populations.
Northwest Montane This habitat is mainly in a 140-mile radius around Kalispell in northwestern Montana. Topography varies from rugged mountainous terrain along the Continental Divide, including the Flathead, Swan and Mission ranges, to more gentle, smaller ranges such as the Salish Mountains. Climate over these 14,659 square miles is strongly influenced by the maritime effect of moisture-laden air from the Pacific Ocean. Precipitation varies between 20 and 32 inches, with more than half falling as snow. Mule deer densities today are generally low across forest areas, but deer may be found on rugged ridge systems and alpine peaks.
Population objective: Maintain the population within 25 percent of the long-term average as measured by the total number of bucks harvested or the total number of deer observed during spring on areas where aerial surveys are feasible.
Mountain FoothillsIn southwestern Montana, west and south of Helena and west and south of Missoula, the area consists of 24,030 square miles of foothills and rugged, mountainous terrain with elevations ranging from 4,000 to 11,000 feet. Topography and elevation cause variations in local climate and weather conditions across this unit. Deer use shrub-grass covered foothills in winter and higher elevation conifer forests and sub-alpine meadows in summer. Deer must cope with long winters and a comparatively short growing season.
Population objective: Maintain the total number of deer observed during spring on population survey areas within 25 percent of the long-term average.
Prairie/Mountain FoothillMainly the east Front of the Rocky Mountains and east along the Missouri Breaks, this is a transition zone with characteristics of both the Mountain/Foothill and Prairie/Breaks units. Topography varies from low, rolling hills to steep, rugged mountain canyons. Elevations range from less than 4,000 feet to over 9,000 feet near the Continental Divide. Precipitation is highly variable, ranging from 10-12 inches at lower, more arid sites to more than 40 inches in the mountains.
Southern MountainsMade up mainly of the Absaroka-Beartooth Wilderness Area, this is a 4,266 square mile area in south-central Montana. The topography varies from rolling hills to sheer mountain canyons thousands of feet deep. Elevations range from 4,500 feet to nearly 13,000 feet. Precipitation varies from less than six inches annual rainfall to more than 40 inches per year in the mountain environments.
Population objective: Maintain the total number of deer observed during spring on population survey areas within 30 percent of the long-term average.
Prairie/BreaksLargely the eastern two-thirds (77,663 square miles) of Montana, the breaks consist of flat to rolling bench land, ponderosa pine savannahs, rugged badlands or breaks adjacent to major rivers. This habitat has a semi-arid climate with large annual fluctuations in temperature and precipitation. Mule deer populations fluctuate more here than in the mountains.
Population objective: Maintain the total number of deer observed during spring on population survey areas within the range of 20 percent above and 30 percent below the long-term average.
Q: What are the most influential factors in deer population dynamics?
Research in Montana over the past 25 years suggests that the most influential factors in deer population dynamics are weather (particularly precipitation), habitat condition, predation and other natural mortality of fawns and adults, overall age structure of a population and hunter harvest. These factors vary from one type of habitat to another in any single year.
Q: What effects do variations in temperature and precipitation have on mule deer populations?
In all mule deer habitats, annual changes in precipitation and temperature during the growing season affect the amount and quality of summer forage. For example, a does summer diet must enable it to recover from winter and meet the demands of raising fawns. In addition, deer must build body fat for the coming winter.
During favorable years, plentiful, high-quality forage meets a deers energy needs. In turn, deer survival is usually high during the coming winter, even if winter conditions are on the severe side. During unfavorable years with hot, dry summers, quality forage is scarce. More energy is expended than is gained and adults and fawns enter winter without the fat layers they need to survive.
Q: How are mule deer populations monitored in Montana?
FWPs aerial deer surveys follow standards set for the data collected, the timing of surveys and the types of aircraft used so that the data is comparable and consistent. Aerial surveys ensure accurate information on size and composition of mule deer populations. Aerial surveys are done annually on 13 representative census areas and 67 trend areas across the state. Data from these census and trend areas provide a network of warning lights that can signal important changes in the size and composition of Montanas mule deer population.
Q: What is a census area?
In census areas precise data describing population size and composition is collected. One full-coverage count and classification is done after hunting season and before antlers are shed (December 1 to January 15). In spring, three full coverage flights are flown (March 15 to April 30) to provide a high level of confidence in the number of deer counted in that census area.
Q: What is a trend area?
In trend areas, a post-season survey is flown to monitor fawn to doe and buck to doe ratios. In spring, all trend areas are re-flown once to count and classify deer when they are most visible on newly greening up open areas.
Q: What role does hunting play in managing mule deer numbers?
Hunting, another form of deer mortality, is the only controllable factor in deer management. Harvest of adult does is the primary tool biologists have to use to affect population size. Biologists and wildlife managers recommend liberal, moderate or restrictive hunting seasons that should, when combined with the other factors at work in a particular mule deer habitat, keep the population within the long-term average observed in that habitat.
Q: How are hunting regulations managed under Adaptive Harvest Management?
FWP regional wildlife managers recommend hunting regulations annually to the FWP Commission. A recommendation for a liberal, moderate or restrictive season is based on the overall status of the deer population in a particular area in relation to the long-term average population observed there.
Q: What is the FWP Commissions role in hunting regulation setting?
The FWP Commissions role is to balance the input of hunters and landowners, while keeping an eye on the status of mule deer populations and trends observed by wildlife managers.
Q: What is Montanas mule deer management goal?
The states deer management goal is to manage for the long-term welfare of Montanas deer resource, while providing optimum hunting opportunities that reflect the dynamic nature of deer populations.
Q: What was learned in ongoing research about the ways deer use their habitat?
Extensive radio tracking and aerial surveys over the years confirm that social, behavioral and family relationships among individual deer play a role in the animals selection of habitat and how the deer make use of those habitats.
Q: How does the social structure of deer populations influence their use of habitat?
Mule deer organize around family groups of two or more generations of related females and their offspring. The dominant member is a mature female with a history of successful reproduction. This female maintains exclusive use of a portion of her home range most important to reproductive success. This behavior stimulates her year-old offspring to begin the process of establishing their own home ranges. Among yearlings studied in the Missouri River Breaks, 84 percent established individual home ranges in the area they were born, at least occasionally overlapping with the range of their mothers.
This connection to home range and the long-lasting social bond between mother and most female offspring plays a significant role in forming and carrying on the successful use of a habitat.
Q: What is fawn recruitment?
Recruitment of fawns is the term biologists use to refer to the reproductive potential of a deer population. Recruitment equals the number of fawns that have survived to approximately their first birthday. That isthe number of spring births minus the total mortalities that occur in the first year. Up to three-fourths or more of the annual fawn crop will die in some years in mule deer populations across Montana. Mortality of fawns is high during early summer, lower through late summer and then goes up again in mid to late winter. Fawn mortality is driven by winter severity, predation, summer forage production, quality and length of time that green succulent forage is available.
Q: What is the significance of fawn recruitment?
When conditions are favorable and more fawns survive, the survivors add to the potential population. So for example, in mountain environments when conditions are favorable and more fawns survive it may require a harvest as high as 20 percent to stabilize the population. In years when fawn survival is moderate, harvests of 10 to 15 percent will stabilize populations. When conditions are severe, the natural losses of fawns and adults will be enough for the population to decline significantly, even with no hunter kill.
How does the computer-monitoring component of Adaptive Harvest Management work and how far is FWP in the development of this modeling capability?
FWP is developing and implementing a computer program capable of integrating long- term population trends with data on ecological factors that cause changes in mule deer populations. The computer can then model the effects of different hunting regulation packages on mule deer in a particular habitat under the conditions specified.
Q: What is the benefit of computer modeling?
Working with the computer modeling and annual aerial monitoring will allow biologists to test their assumptions against years of hard data and to identify inconsistencies for further study.
