Mountain Ungulates of the GYE

Chapter 1: Natural History

Bighorn Sheep

• Bovidae family

• 175-250 lbs Ram

• 130-190 lbs Ewe

• Hooves blunt, widely cleaved

History

• Historically 2 million in North America

• Numbers decreased

  • Domestic sheep

  • Late 1800’s

• Forest Service established

  • Domestic sheep down 

    • Overgrazing concerns

    • Still down today

Habitat and Diet

• The defining feature is closeness to rugged, steep terrain where sheep can escape from predators

• Open Country

• Long views

• Winter in low country or high elevation wind-blown area

• Feed on 37 different plant species

• Prefer grasses to forbes

Disease and Parasites

• Pneumonia

• Mycoplasma ovipneumoniae

• Fatal pneumonia often develops in bighorn sheep following contact with domestic sheep

• Domestic goats also transfer disease

• Infectious keratoconjunctivitis

  • Pinkeye

• Contagious ecthyma

  • Sore mouth

  • Orf

Mountain Goats

• Males 40% heavier than females

  • 190-245 lb Billy

  • 120-160 lb Nanny

• Forequarters are well muscled for up-hill climbing in steep terrain

• Broad-oval shaped hives

  • Splay to increase traction when descending steep slopes

• Dermal shields- thick skin on their rump to protect from punctures 

History

• Native to coastal and inland mountain ranges west of the continental divide 

• Rare until the late 1900’s

  • Currently 75,000-110,000

Habitat and Diet

• Habitat specialists

• Increase weight by 38% in summers

• Generalist herbivores

Population Dynamics

• The greatest limiting factor is extreme weather

• First young at 3-4 years old

• Twinning is uncommon not rare

  • Higher among introduced populations

• 22% annual increase over 12 years in introduced populations

Chapter 2: Historic Information 

Original Distribution

• Two million bighorn sheep west of the Mississippi

• Fossils of mountain goats from 70,000 years ago were found near the Palisades Reservoir 

  • Goats found in GYE up until 10,000-15,000 years ago

• 1883 ban on hunting in Yellowstone

Influence on native people

• Sheep were a staple resource for 

  • Food

  • Clothing

  • Glue

  • Tools

  • Bows- 60-70 lb pull

Effects of Euro-American Settlement

• 1860’s and 1870’s - Arrival of prospectors and settlers

  • Used the Bozeman Trail

• 1862 Homestead Act

• Many settlers in the northern part of the GYE were shepherds from Norway

• Market Hunting 

  • Slaughtered tons of bighorn

  • 2,000 sheep taken in the spring of 1875

• Tribes struggled

  • Settlement of their lands

  • Disease outbreaks

  • Slaughter of food sources

• Sheep Struggled

  • Suppress fires leading to conifer invading grasslands

• 1862 Pacific Railway Act

  • A rapid increase in livestock

  • 1881 <30,000 domestic sheep

  • 1894 >500,000 domestic sheep

  • 1920 ~10 million domestic sheep

• Ranchers grazed cattle horses and sheep inside Yellowstone NP from 1875 to 1922

• The need for wool during world wars kept sheep going until the 1950s 

• Livestock grazing led to 

  • Overgrazing 

  • Soil Erosion 

  • Displacement of wildlife

  • Disease Spread

• Most livestock diseases are currently present in wild bighorn sheep

Conservation Efforts

• Market hunting, habitat destruction, disease

• Replaced by limiting harvests and protecting habitat

• Forest Reserve Act 1891

  • Preserved 6.5 million acres over the first 12 years

• National Forest Service 1905

• Yellowstone National Park Protection Act 1894 

  • Banned hunting and wildlife harassment 

• Wilderness Act 1964

• Endangered Species Act 1973

  • Grizzly listed 1975

  • Domestic sheep grazing is limited to reduce conflict with Grizzly

• 1978 Absaroka and Beartooths designated wilderness area

• 1983 only three operations left in these ranges

  • Vs 110,000 sheep in 1913

• 2003 last year of grazing in high country

• No domestic sheep grazing on federal lands where native populations of bighorn sheep lived in Wyoming by 2017

• Relocations

  • 1920’s-1990

  • 1,500 relocations

  • 21,500 sheep

  • Numbers increased

  • Began to relocate mountain goats as well

Current Status

• 50,000 Rocky Mountain Bighorn Sheep

  • 10-fold decrease from historic numbers

  • 2 fold increase from historic lows

• Complicating Factors

  • Widespread respiratory disease

  • Habitat loss

  • High Predation

  • Human recreational activities

• 5,600-5,900 Bighorn Sheep in GYE

  • 4,000 in Absaroka and Beartooths alone

  • Most populations are isolated and fewer than 150 individuals 

• 1,600-2,300 mountain goats

  • Likely to increase 

• Non-for profits paid ranchers not to graze on public lands

  • Removed livestock from 70,000 acres

Conclusions

• Bighorn numbers in GYE are still way below pre-settlement conditions 

• Mountain Goat concerns over impact on native plants, competition, and diseases

Chapter 3: Seasonal Habitat Characteristics

Introduction

• Bighorn live in river canyons and on prairie breaks

• Goats have expanded into steep canyon regions such as Clarks Fork of the Yellowstone

What is Habitat?

• Collection of resources and conditions in an area that allow an animal to survive

  • Food

  • Water

  • Mineral licks

  • Thermal cover

  • Shelter from predators

• Habitat use varies between males and females and seasonally

• Regular fire cycles increase visibility and improve habitat quality

Conducting Habitat Research

• Locate animals frequently

• Characterize attributes such as

  • Topography

  • Vegetation

  • Cover

  • Human alteration

Seasonal Habitat Associations 

Bighorn Sheep

• Breeding

  • Mid-November- End of January

• Segregate by sex after breeding season

• Most influential habitat attributes:

  • Slope

  • Ruggedness

  • Elevation

• Summer Range

  • Steep rugged slopes at high elevations

  • North-northwest facing slopes in summer

• Winter Ranges

  • Low-elevation valley bottoms with less snow

  • High-elevation residents prefer low-angle windswept plateaus and 35-40-degree slopes that shed snow

  • South-Southwest facing slopes

• Often found on 

  • Terraces

  • Ledges

  • Grasslands

• Actively avoid dense forests

• Isolated, small ledges within steep terrain with good visibility make good birthing and nursery sites

Mountain Goats

• Highly dependent on terrain

  • Need a steep slope angle

  • Summer ranges average 37*

  • Minimal canopy cover

  • Cool northeast aspects in summer and warm southwest aspects in winter

• Low-temperature threshold (not heat tolerant) 

• Birth on isolated ledges

  • Enough early forage is available on warm aspects within broader rugged landscapes

• Avoid predators by avoiding forests

• Most socially dominant individuals use preferred bedding sites

Habitat Overlap

• Mountain goats were historically absent or scarce in GYE

• Bighorns tended to use relatively low elevations compared to goats

  • Stronger avoidance of forests

• Goats winter in steeper habitats than bighorn

• Habitats broadly overlap

• Habitat attributes may not be limited as habitat is expansive

• No evidence of disease transfer in GYE

  • Documented outside of GYE regularly

• Native bighorns are the management's priority

• Managing for lower densities of goats

Mineral Licks

• Three Types

  • Dry-earth

  • Wet muck

  • Rock faces

• Locate mineral licks by looking for

  • Benches

  • Abrupt reductions in slope-angle

  • seeps 

  • Other areas of water deposition

  • Often found at road cuts

• Goats and Bighorn both make lengthy and direct movements to licks located outside of their seasonal ranges

• The use of licks peaks in the spring and early summer

  • Poor winter diets 

  • Accessibility

  • Males access first 

  • Females peak with birth and lactation

• Seeking important minerals 

  • Sodium

  • Magnesium 

  • Offset high levels of potassium found in spring forage

  • Stabilize rumen pH

• Goats appear to be dominant at licks

  • Critical sites of disease transfer

  • Camera traps help us understand their use

Human Disturbance and Habitat Concerns

• Deposition and concentration of human urine

• Killed a hiker in Olympic NP

  • 2019 removed 300 goats

• Cumulative effects of development

  • Roads

  • Fences

  • Housing

  • Domestic livestock grazing

  • Skiing

  • Snowmobile

  • Ice climbing

• Many low-elevation populations no longer have a migration component

• Goats live on steep mid-elevation slopes and are less susceptible to human impact

• Exotic weeds and conifer encroachment 

  • Reduce forage quality

  • Reduce habitat quality

• Winter recreation in Grand Teton 

  • 30% reduction in available habitat

  • Helicopter noise

    • Results in impact up to 2 days after a flyover

•  Climate change 

  • Reduce snow accumulation

  • Increase access to forage

  • Increase the frequency of hardened snow events

Chapter 4: Mountain Undulate Migrations

Introduction 

• Migration- an animal behavior involving repeated seasonal movements of individuals between distinct seasonal ranges, round-trip

• Overall these movements benefit the individual

• There is a cost to migration but it is always offset by the benefits

  • Increased survival

  • Increased reproduction

• Primary influences of migratory behavior

  • Learning

  • Memory

  • Social communication

• Don’t know the exact cues that signal when to migrate

• Both sheep and goats are considered migratory

  • Exhibit different migratory behaviors/strategies

Bighorns

• May travel up to 30 miles

• Partially migratory: Some members of the population choose not to migrate

• Migration lasts 7-14 days

• High-elevation animals make a ‘reverse migration’ in the spring to avoid snow-hardening events

• Lambing occurs in late May and early June

Mountain Goats

• Considered migratory but

  • Shorted distance between ranges

  • Less well-defined movements

  • Vertical movements

  • Become solitary

• Summer ranges around 9,000 feet

• Winter ranges around 6,500 feet

• These numbers vary with latitude

• Average migration 3 miles over a couple of days

Migratory Diversity

• Refers to the proportion of a population that exhibits migratory behaviors

• High migratory diversity 

  • Increases the number of seasonal ranges

  • Buffers from the effects of human disturbances

  • This leads to greater genetic diversity

  • Helps with population stability

• Low migratory diversity (when all individuals in a population exhibit the same behavior)

  • Local conditions or disturbances can negatively affect the entire population

• Herds have a “Historic Knowledge” of migratory behaviors

  • Restored populations do not have this knowledge

  • So far there has been no success in restoring this migratory knowledge

Threats to Migration

• Once lost migration is exceedingly hard to restore

• Landscape development is the biggest factor leading to loss of migration

• Livestock grazing increases the chances of contracting new pathogens

• The delicate balance between changing temperatures and foraging conditions at various elevations due to climate change

Conserving migration

• Scientists have focused on 

  • Making maps 

  • Larger data sets

Conclusions

• Both species have some partially migratory populations

• Major threats are posed by

  • Habitat loss

  • Human barriers

  • Climate change

Chapter 5: Genetic Attributes and Research Interests

The Genomics Revolution and Yellowstone

• 1985 Polymerase chain reaction invented

• Thermus aquaticus, a Yellowstone hot spring discovery was instrumental

• Taq polymerase was the key that allowed high temp, faster DNA reproduction

What is DNA and how do wildlife biologists use it?

• The following all influence wildlife populations

  • Gene flow

  • Mutation

  • Selection 

• Bighorn genome- 2.9 billion base pairs

• Mountain Goat genome- 2.5 billion base pairs

  • Both are pretty unwieldy 

• Mitochondrial DNA for both ~16,000 base pairs

• DNA from both is relatively similar

  • Areas of differences called Loci

Ancient Populations

• Bighorn have been on the landscape for thousands of years

• Important food sources and resources for native peoples

• 1877 Yellowstone Superintendent’s report

  • Several thousand bighorns were removed from the area 

  • Mostly for pelts

  • Major loss of genetic diversity

• Exotic respiratory diseases caused a further bottleneck

  • Exotic pathogens are present in nearly all bighorn populations currently

• The genome of the pre-settlement bighorn likely represents the historic condition of the native sheep when their populations were numerous and free of disease 

  • Using old bones we can determine historic population size and health

  • Using this scientists plan to determine the effects of market hunting and domestic sheep grazing 

  • Also, evaluate how the stability of ewe home ranges might affect how bighorns are related across geographic areas

Evaluating genetic differences between today’s bighorn herds

• Many relocations

  • 1,460 translocations

  • 21,500 bighorn

• Three introduction methods

  • Started from distant sources

  • Supplemented native herds with distant sources

  • Pure native herds

• Use SNP (Snips) to determine how long populations have been separated

  • SNP’s are pieces of genetic code with repeats (ATATATAT)

  • ATATAT will be more closely related to an animal with ATAT than AT

  • These SNP have fairly well-documented mutation rates allowing us to determine separation time

  • Ovine high-density SNP chip is the preferred site of interest 

Determining relatedness within Bighorn Herds

• Kinship

  • Measure of relatedness

  • A large randomly breeding population would have a mean kinship near zero

  • Extraordinarily inbred animals approaching 1

• Kinship values were consistent with expectations

  • The highest values were near .064

  • High but not of concern

• Kinship is a helpful piece of information, not a diagnostic device

Mountain Goat Genetic Research

• 170 goats were released in the GYE at 7 locations north of YNP in the late 1940s and early 1950s and at 2 locations southwest of GTNP in the '60s and '70s

  • Each location received between 5 and 33 goats

• Areas with low numbers introduced experienced significant genetic drift

• Geneticists use DNA parts called microsatellites to assess the movements of populations

  • DNA that is inserted or deleted at random

  • Always non-coding DNA

Using genetics to assess isolation and sources of nonnative mountain goats in GTNP

• Goats were first observed in the late 70’s

  • Likely transients 

• Nanny and Kid spotted at Grand Targhee regularly in 2005

  • Breeding population

• In December 2018 biologists counted 88 individuals

• The source is likely the Snake River Range 25 miles south

  • 12 goats were introduced in the late 60’s in Palisades, ID

• The nearest native goats to the Tetons are 106 miles to the north at Lima Peaks

• Genetic analysis of Teton herds shows close relatedness to the Snake River Herd

Chapter 6: Health and Disease

 Introduction

• Over a century of disease reports in Bighorn in YNP

  • The earliest is 1880’s

• Infections can lead to catastrophic losses

• Currently, respiratory diseases already present can affect young lambs

  • Leading to poor lamb recruitment

  • Can last for decades after the initial infection

Origin and Transmission of Respiratory Disease

• Originated from domestic livestock

• New exposures can result from either domestic livestock or other mountain undulates

A complex history of diseases

• Psoroptic mange in late 1800’s 

• Lungworm in 1927

  • Parasitic nematodes

  • Commonly thought to lead to secondary infection of pneumonia

  • Increasingly common in the mid-1900s

• Bovine respiratory syncytial virus and parainfluenza 3 1960’s

• Pasteurella bacteria in 1980’s 

• Mycoplasma ovipneumoniae found in 2008

  • This can lead to clinical signs of respiratory disease

  • Does not consistently lead to mortality

  • Different strains lead to different disease outcomes

  • Causes unusual changes in sinuses of bighorn

    • Overgrowth of sinus lining the bone

    • Sinus tumor

    • Tumors appear to be infectious 

      • Virus is suspected

      • 2016

• Fusobacterium necrophorum

  • Another important cofactor in the disease state

Current Understanding of Respiratory Disease

• Ecological factors at play

  • Habitat availability 

  • Forage quality

  • Trace minerals

  • Population density

  • Predation

  • Translocation efforts 

  • Loss of population knowledge

• Animal factors

  • Nutritional state

  • Immune competence

Respiratory disease in Mountain Goats

• Pathogens of bighorns also identified in goats

  • Lungworm

  • Mycoplasma

  • Pasteurella

  • Sinus tumors

Epidemiology and Similarities to Domestic Disease

• Similarities in pathology to “shipping fever” in cattle

• The disease is caused by the interaction of primary stressors 

  • Weaning 

  • Shipping 

  • Handling 

  • Nutrition

• There are many complex interactions between the agent, host, and environment

History of Respiratory Disease and Outcomes in the Greater Yellowstone Ecosystem

• Dies off from pneumonia recorded in the early 1920’s

  • 1,207 dead in 1934

  • 234 dead in 1938

• Psoroptic mange die offs in the 1880’s

• The steady expansion of mountain goats suggests disease is not a major goat issue

Respiratory Pathogens in Bighorn Sheep and Mountain Goat Populations

• Pasteurella bacteria present in all tested populations except the Tetons

• The same bacteria have been found in all mountain goat populations except the Teton

• Areas with previous exposure have resiliency

• Resilience also related to 

  • Habitat availability 

  • Population size

  • Attenuation (lessening of severity)

Other Diseases and Parasites

• Contagious ecthyma

  • Orf

  • Soremouth or Scab mouth

  • Sporadic mortality

  • Zoonotic disease

• Keratoconjunctivitis

  • Pinkeye

  • Low mortality

  • Cloudy or milky eyes

  • Cause by Chlamydia sp. Bacteria

  • 1980s die off of 60% (300 of 500 animals)

• Bluetongue virus

• Anaplasmosis

• Johne’s disease

• Malignant catarrhal fever

• Bovine viral diarrhea

• Necrobacillosis 

• Numerous internal parasites

Assessing Nutritional and Physiological Status

Chapter 7: Populations Dynamics

Introduction

• We notice and appreciate individual animals while wildlife watching 

• Conservation and management focus on populations 

• Difficulties defining populations 

• Biologists conduct surveys to assess “how well a population is doing”

  • Stable, increasing, decreasing

• Population stability is a function of reproduction, survival, and movement

• Metapopulations are an interacting set of subpopulations

  • This is the ideal

• There are 16 recognized subpopulations in the GYE

  • The largest metapopulation in the eastern Absaroka range

  • Another metapopulation in northwest Yellowstone

    • The Upper Yellowstone Complex

• Identifying mountain goat populations is even more difficult

  • Limited data

  • Highly restricted home ranges

• Agencies also track the age and sex of all harvested animals 

• Radio-collared adults are used to access pregnancy and mortality rates

Reproduction

• The breeding season for bighorns is mid-November through mid-December

  • Breeding coincides with peak conditions for both species

• Annual pregnancy rates for bighorn 87-95%

  • No pregnancy rates for GYE goats exist

  • Canadian numbers suggest a similar percentage

• Both Bighorn and Goats are polygamous

• Mature bighorn rams are 40% larger than ewes

  • 175-250 Rams

  • 130-190 Ewes

• Similar for goats

  • 190-245 Billy

  • 120-160 Nanny

• Bighorn rams participate in head-on-head ritual combat

• Mountain goat billies use their horns to attempt to strike their opponents on the flank or rump

  • Serious wounds are rare but punctures and slashes are common

  • Males have thick dermal shields .6-.9 inches thick

• Gestation for both is approximately 6 months (170-180 days)

  • Females usually separate from the herd

  • Seek out isolated locations in rugged terrain 

  • Seclude for several days to a week

  • Single lambs most commonly twinning rare

  • Goats have had more common twins and even triplets reported

• Twinning frequency is an index of the relative quality and quantity of forage available on the summer range 

• Young typically weigh between 7 and 9 pounds

• Nursery herds can exceed 50 animals 

• Lambs and Kids begin eating vegetation around 3 weeks 

  • Weaning occurs between late July and September

• Young are independent by spring 

• Social bonds with bighorns last until the spring but goats often continue into the next year

Survival rates and the causes of mortality

• Survival is the probability that an animal alive at the start of some defined period of time will still be alive at the end of the time period

• Survival varies based on age

• Low survival during the first year of life, rapidly increases to maximum then wanes in old age.

  • The major mechanism responsible for the decline in survival is tooth wear

• Much of an ungulates time is spent eating

• Plants are abrasive because of their structure and chemical composition and due to fine soils that stick to their surface 

• Survival rates differ by sex

  • Males tend to live shorter lives than females

• Bighorn sheep abundance is particularly sensitive to the survival of adult females 

  • Average survival for females is 80-93% 

• Mountain goat survival is slightly lower 86-80%

  • This is likely due to the inclusion of males 

• Sources of mortality

  • Mountain lions, wolves, grizzly bears, black bears, coyotes, golden eagles, accidents (falls from a cliff), avalanches, vehicle collisions, disease, long or deep snowpack, hunting (2-4%)

Recruitment

• ‘Birth Pulse’ causes a dramatic increase in population size all at once

• A large portion of young die before their first birthday

• Biologists regularly collect information on recruitment via aerial surveys

• Recruitment rate is the ratio of young-of-the-year to adult females

  • Kid to adult ratio

  • Expressed as a decimal or percentage 

• Recruitment rates tend to be much lower than survival rates and vary widely

• GYE recruitment typically varies between 19 and 41%

• Typically 80% of females are pregnant in a given year

• Meaning between 50% and 75% of young die in a given year

• Recruitment under 20% is considered not sustainable

Dispersal

• Reasons for dispersal

  • Leave and settle in new areas

  • Some animals are just wanderers

  • Some searching for important resources

  • Food

  • Mates

  • Social tension

• Goats tend to be more exploratory 

• Bighorns demonstrate less tendency to disperse

  • Remain in same local despite increasing densities

  • Particularly in populations that are reintroduced

• Taylor-Hilgard population

  • Increased population size

  • Little expansion into adjacent high-quality territory

  • Become increasingly vulnerable to predation and disease

Abundance and Population Trends

• Everyone wants to know

  • How many animals are in the population?

  • How has the population changed over time?

• Questions are challenging to answer accurately

  • Large complex landscapes

  • Distributions change dramatically with variables

    • Food quality

    • Food quantity

    • Snowpack

    • Predators

  • These animals tend to exist in small groups and are easily hidden by rugged terrain 

• Population surveys likely detect 60-80% of animals 

  • 5,700-5,900 Bighorn Sheep

  • 1,700-2,400 Goats in GYE

• Bighorn sheep conservation success story!

  • Most bighorn in the west were extirpated

  • 1,000,000 sheep to less than 25,000

  • 2016 50,000 animals in the west

    • Restricted in range

    • The result of 1,400 translocations with 25,000 animals

• GYE has the largest continuous distribution of bighorn sheep in North America

• Mountain goats have become widely distributed and well-established

  • The result of introductions

  • Populations are starting to stabilize in some areas

  • Continues to increase in the GYE

  • Areas of concern are the Absaroka and Teton ranges

Chapter 8: Impacts of Expanding Introduced Mountain Goats 

Range Expansion

• In one human lifetime, goats have expanded from 0 to 2,355 individuals (2014)

  • Done through 157 relocations

  • Goat to increase big game hunting

  • 40s-70s

• YNP count

  • 24 in 1997

  • 178 in 2009

  • 209 in 2014

• Aptitude to disperse across unsuitable habitats

• Considered non-native

• Compete for forage and space

• Negative impacts on disease transmission and plant communities

Range Overlap with Native Bighorn Sheep

• Use similar habitats and share native ranges outside of GYE

• Differ in selection of seasonal home ranges, habitat types, and food

• Potential for substantial negative impacts on bighorn populations

• Competition for limited resources via aggressive displacement 

  • 100 interactions 

  • 37% bighorn were deterred from resource acquisition 

  • Must wait to utilize salt licks

  • Strong overlap in forage resources in winter 

• Goats prefer forbs and bighorns prefer grasses

• 30% overlap in feeding sites 

• Differ in preferences for slope, canopy cover, and elevations 

  • Differences not strong enough to cut spatial overlap

• Reason to believe that goats will adversely affect bighorn sheep once they completely colonize a given habitat

Potential Impacts to Native Plant Communities

• Native plants are sensitive to 

  • Bedding

  • Grazing 

  • Trailing

  • Wallowing

• Documented declines in alpine and subalpine plant cover

  • Increased bare soil

  • Altered rates of nitrogen cycling 

• YNP study found damage was restricted to the tops of ridge lines

  • Hypothesized that YNP has resilience from grazing of bighorn, marmots, etc

  • Bighorns never present in Olympic NP

Potential for Continued Range Expansion

• High kid-to-adult ratios

• Currently occupy 43% of previously unoccupied areas

• Carrying capacity 5,300-8,850 goats

• The limiting factor is winter ranges and competition

• 75% of current sheep ranges fall within the parameters for suitable goat habitat

• Colonization of GTNP

  • First observed in 1970s

  • Concentrated between cascade and Snowshoe Canyons

  • Rapidly growing

  • Can support 250-400 goats

    • 2.5-4 times pre eradication numbers

Complexities of Managing Mountain Goats

• Multiple federal and state jurisdictions

  • Each has different goals, missions, and mandates

  • 67% Federal Lands

    • 48% Forest Service

    • 11% Park Service

    • 7% BLM

  • 27% Private Lands

  • 4.2% State

  • 1.8% Tribal

• States typically manage for conservative harvest and discouragement of further range expansion

• USFS classifies bighorn as a sensitive species

  • Requires special habitat conditions to be preserved

• Park Service's goals are to conserve native species and communities

• Wyoming Game and Fish achieve goat objectives by hunting in the Absorkas

  • It has proven less effective in the Teton Range

  • The number of Goats in the Tetons is relatively low and therefore preventing further expansion of goats would involve the removal of fewer animals which may be more socially acceptable and reasonable to fund

Future management of Mountain Goats

• Populations of bighorn sheep in the Teton Range is especially sensitive due to their constricted range, small size, unique genetics, behavioral adaptations, and susceptibility to pneumonia-causing pathogens

• Absaroka population is the largest, most robust with 4,000 animals

• 85% of rocky mountain bighorns reside in Wyoming

• There is a liberal mountain goat hunting season in the Absaroka Ranges

• Translocations of over 21,500 bighorn sheep resulted in populations of only 50,000 animals

• A significant portion of bighorn occupy high-elevation winter ranges

• The delicate interplay of dry, wind-blown, snow-free ridges that exist through mid-late winter

• Increasing temperatures in high elevations disrupt the freeze-thaw cycles

  • Renders forages unavailable

• Pathogen transmission risk persists

Conclusions

• Manages intentionally introduced goats in the 1950s-1970’s to provide hunting and viewing opportunities

• Goats have grown to occupy over 43% of viable habitat

• Competition and disease transmission are the biggest threats to bighorn populations

• 2,000 goats currently, possibility over 9,000 goats

• Near certain to have adverse impacts on 6,000 sheep currently in the GYE

• Goats perfectly suited for the mountainous habitat of GYE

• There is no single solution

Chapter 9: Current Management

Jurisdictions and Mandates 

• North American Model of Wildlife Management tenet that the public owns wildlife

• Management activities

  • Habitat enhancement

  • Hunting

  • Landowner agreements

• NPS Policy

  • Hands off

  • Allow populations to fluctuate in response to forage, predation, weather, and competition

  • Hunting was prohibited in 1894 in National Parks

• The policy recommends the management of non-native species that interfere with the native wildlife or their habitats, up to and including eradication, if such control is prudent and feasible

• All managers have the shared goal of conserving, recovering, maintaining the public trust, reducing property damage, increasing human safety, and doing so by basing our decisions on reliable information

Population Management

• Broadly defined as the process of dealing with or controlling things or people

• Adaptive management

  • Often used due to unpredictable environmental variation, difficulties collecting data, and the need to make assumptions

  • The continual process of evaluation and adjustment includes determining an objective, applying a management action, measuring progress toward achieving the objective, and adjusting subsequent management actions

• Hunting is the primary tool used to meet population objectives in both goats and sheep

• Bighorn hunting centers around the take of adult males

• Montana has a ewe hunting season in specific areas 

  • Maintain lower densities in specific areas

  • Often related to winter forage availability in specific areas 

  • Minimize the risk of disease outbreak

• Either sex of mountain goats is often allowed as sex is difficult to determine 

• Capture and relocation is another control method

  • Drop nets, corral traps, chemical immobilization, aerial net-gunning

  • 1989-1997 46 mountain goats were removed from the Snake River Range

Habitat Management

•  Maintain habitats for native species and, in some cases desirable non-native species

• Management of oil and gas development, road-building, timber harvesting, livestock grazing, and recreation

• Enhance habitat with prescribed fire, managed wildfires, timber harvest, herbicide treatments

• Sheep are grazers and thus prefer high visibility so fire and mechanical treatments that remove vision-obstructing trees and shrubs and increase the production of preferred forage grasses are beneficial

• Removal of undesirable weeds like cheatgrass

Disease Management

• Buy-outs of sheep ranches and ranching permits 

• Primarily benefiting bighorn sheep such buy-outs have helped individuals permitted to experience depredations from recovered large carnivores such as bears and wolves

• Often controversial and often litigated

• Wildlife agencies may cull individuals showing signs of diseases such as pneumonia

• Removal of Bighorn sheep observed commingling with domestic sheep or goats

• “Stray Livestock” statute in Wyoming

  • Protocol for removing such animals if they pose a disease risk

• Wyoming “Statewide Bighorn Sheep-Domestic Sheep Interaction Plan

  • Prioritizes the state bighorn sheep herds with respect to their origin and importance, with native herds receiving the highest respect for their origin and importance, with core native herds receiving the highest level of protection, and translocated herds receiving less emphasis

• Identification and removal of chronically infected pathogen “carriers”

• Vaccines are problematic as they inhabit high-elevation habitat

  • May eventually become more feasible 

Funding

• Federal funding from congressionally appropriated tax dollars

• State hunting licenses and Federal Aid in Wildlife Restoration Act

  • Pittman-Robertson Act- Tax on arms and ammunition used to fund wildlife surveys and research, acquisition, and improvement of wildlife habitat, translocations, development of public access, and hunter safety programs

• State funding is limited as agency revenues generated by hunting license sales do not cover the cost of annual population and disease monitoring

• Mule deer and Elk dollars often subsidize the mountain ungulate costs

• Governors Tags and Special auctions, single sheep for as much as $480,000

  • 10,000-15,000 more typical in Wyoming

  • Money donated to agencies such as “The Wild Sheep Foundation” or Rocky Mountain Goat Alliance

Bighorn Sheep Management

• Focus on re-establishment

• 10,000 (1960) - 50,000 (2017)

• 1,500 Translocations

• 21,500 Sheep

• Typically one release site

  • Low-elevation winter range

  • Accessibility

  • Ease of capture

  • Leaves populations vulnerable

• 50% of sheep populations have fewer than 100 individuals

• Recent focus on geographically distributed metapopulations

  • Connected suitable habitats

  • A broad range of behavioral traits

    • Migration strategies

  • Promotes resilience

    • “Portfolio effect”

• Montana is attempting to create metapopulations 

  • Translocating individuals very close to familiar territory

  • Retain local knowledge

  • No pathogen risks

  • Along the Madison River

• Some success in creating more viewing and hunting opportunities 

• 95% of visitors participate in wildlife viewing

  • 15,640 Jobs

  • 1.5 Million in economy

  • Geyser viewing (87%)

  • Hiking (39%)

  • Camping (27%)

  • Fishing (13%)

• 400 Hunting opportunities per year in Idaho, Montana, and Wyoming

  • 350 Rams taken

  • 158 from GYE

  • 50,000 people apply

  • Compares to 80,000 elk harvested each year

Mountain Goat Management

• Generally considered non-native species

• 17 Translocations

  • 157 Mountain goats

  • 14 in Montana

  • 3 in Idaho

• The current population of 2,100 Goats

• Goats more successful translocations

  • 15:1 Return on goats

  • 2:1 on sheep

• Hunted to “discourage expansion” 

• Capacity for 5,400-8,900 goats in GYE

• Unlikely that there could be this many goats and not adversely affect 6,000 bighorn

• NPS allows for: “Removal of non-native species that interfere with native wildlife or habitats if such control is prudent and feasible” (2016)

• Rocky Mountain National Park and Dinosaur National Monument remove goats when they are detected

• Olympic National Park removed all goats from the park

Goats in the Tetons

• Brought to Snake River Range between 1969 and 1971

• Observed on Teton Pass in 1977

• First in Grand Teton in 1979

• Sporadic sightings until 2008 when a breeding population arose 

• Numbers have increased dramatically since 2008

• Surpassed bighorn numbers in 2018 (100 goats)

• Highest Priority Sheep Herds

  • Winds

  • Gros Ventre

  • Absaroka

  • Hoback

  • Tetons

• Teton sheep confined to high elevation winter range (8,500)

  • Once migratory

  • Fire suppression

  • Domestic grazing

  • Conifer encroachment

• Teton sheep naive to goat pathogens

  • Absaroka sheep already share all known pathogens with goats

• Beartooth and Snake River ranges continue to be managed for a robust goat population

  • Liberal hunting to control expansion

  • Odds of draw ~1%

  • 30/year in Wyoming

  • 46/year in Idaho

  • 180/year in Montana

  • 161/year from GYE

  • 86% of the harvest from introduced populations

    • Opposite of 50 years ago

Conclusion

• Maintaining robust metapopulations of bighorn sheep where they exist is undoubtedly the best approach to the persistence of bighorn sheep on the landscape

• Recreating metapopulations is not easily achieved