25 Years of Wolves in Yellowstone
Chapter 1
Historical and Ecological Context for Wolf Recovery
“We killed off wolves- it was government policy. Then we brought them back”
Carnivore guild recovery
Looking back to look forward
Haines 1977 3 part history*
Whittlesey 2006, 2007, 2015
Wolves are a symbol of wilderness and the West was being settled.
Wolf History and NPS Policy
1st account
John Weavers: “Wolves of Yellowstone”
1978 survey found no wolves
Recommended reintroduction
Doug Houston
1982 Predators of Elk
Recommended reintroduction
“Wolves for Yellowstone?” Report (1990 and 1992)
ESA, EIS, NPS, USFWS
The Founding goal of Yellowstone was incomplete without wolves
Prolonged fight over:
“Natural”
“Game species”
1800’s
Ecology unknown
“Ecosystem used first in 1935
1900’s
Preservation mindset, ill-formed ideas of ecosystems
1916 Organic Act
NPS
“Parks as scenic beauty”
“To conserve the scenery and the natural and historical objects and the wildlife therein.”
No idea of top-down forcing
Pre-Park History
15,000 years of wolves
Stable for 3,200 years
Pre-1916 wolves had twice the genetic diversity of modern wolves
The population of 100,000 continent-wide
Subspecies
1944: 24 subspecies
Morphology C.l irremortus
1995: 5 species
Genetic C. l. Nubilus
Primary subspecies
The exact distribution of these subspecies is unknown as wolves disperse long distances and lack reproductive barriers.
Rapid and great variation in behavior and morphology leaves ecotypes as a better way to characterize wolves.
Western influence began in the late 1700s
Intensified in the 1860s
Fur trade in the 1820s took wolves (also beavers!!)
Introduced diseases
Introduced horses
Trade with natives
YNP is one of the few areas that never;
Fenced
Mined
Logged
Grazzed
Not pristine or natural
Predator control
Fire suppression
Removal of natives
Bison ranching, elk culling
1836-1839 abundant wildlife
Wildlife extirpation dates
Wolves 1929
Cougars 1930
Coyotes 1940
Park History
1871-1885: Mining camps in Cooke City hosted miners who killed everything
Poisoned ungulates with strychnine
- 1885+ military called in to stop the slaughter
Increased ungulates
Decreased predators: control matters taken
1934- 1968 Elk Control
Woody plants vs. grasses growth
Too many elk?!
No Aspen recruitment for 100 years
1963: Leopold Report
“Natural regulation”
Less human conflict
Maintaining ecological processes
Elk reduction ended
Pave the way for wolves
The elk herd swelled to 20,000 in the northern range
Chapter 2
How Wolves Returned to Yellowstone
“Are we really better off without wolves in the wilder parts of our forests and ranges?”
Aldo Leopold
Paved the way and placed YNP at the forefront of every wolf discussion to come
Changing Viewpoints
Appreciated by Indigenous
Associated with evil by whites
1915, the USFWS killed wolves in the West.
1916-1926 NPS killed 136 wolves
1940’s-1970’s less than 10 wolves were killed
1970’s- 1980’s, more study led to more understanding
Increased acceptance
More radio telemetry work
Rumors of wolves in YNP
No evidence found
Endangered Species Act 1973
Wolves listed!
1986 The Magic Pack
Denned in Glacier National Park
First wolves in the US Rocky Mountains
Some ate cattle
Canis lupus politicus
1986 and 1987 Pro vs Anti-wolf camps
1988 Wolf Management team
ESA 10(i) reintroduction of “non-essential experimental” population
More management flexibility
Eliminated ESA review
Allowed USFWS to manage human conflict more quickly
Defender of Wildlife compensated ranchers for livestock killed by wolves
L. David Mech
Biologist and wolf advocate
Dick Cheney is strongly anti-wolf
“The oft-cited narrative of economic impact is a mask for the concerns of power loss through the changing west”
Ranchers, not fans
Loss of control
Inability to find remains
“Wolves for Yellowstone?”
Study of potential wolf effects
592 pages penned in 1990
Wolf control
Inside vs. outside of YNP
Prey affects
Grizzly effects
Recovery zone layout
Conclusions
No major effects on prey populations, big game, or grizzly
150 wolves in/near the park
7-9 packs in north/central YNP
Volumes 3 and 4
750 pages
Prehistory, historic populations, sociology, economics, other relocation outcomes
Anti-wolf Idaho senator introduced a proposal to reintroduce wolves
Fear of wolves being put on ESL
More management options
Bill would immediately delist the wolves
Bill died
10-member Wolf Management Committee
Pro-wolf = Anti-reintroduction
Weakened ESA protections
Economic Impact Statement
1994
Recommended reintroduction as a “nonessential experimental population” to both YNP and Central Idaho
Allowed removal of wolves by agents and authorized citizens
Reintroduction Efforts
Where to obtain wolves?
Monitor “donor populations”?
Transportation?
Release type?
What time of year?
Demographics?
Homing tendency concerns?
Western Canadian Wolves
Mountainous habitat
Similar prey base
15 wolves per year over 3-5 years
Family groups in YNP
Unrelated Young Adults in Idaho
3 months in acclimation pen
1-2 acres
5 miles apart
7 pens total
November capture, February release
Republican congress voted in 1995
Wyoming lawsuit December 21-23 1994
Reintroduction could continue during litigation
Capture and Transportation
Capture team
Veterinarians, marksmen, pilots, biologists, spotters, trappers
Crop conditions
Too little snow, too much forest
28 wolves
11 packs
11 days
Additional trapped wolves were released
14 wolves to YNP in 3 packs
15 to Idaho
12 left in Alberta
American Farm Bureau appeal
10 circuit court
48-hour stay
Kept wolves in boxes
Ice cubes used for hydration
90 hours in Idaho
First YNP Pens
Crystal Creek
Soda Butte Creek
Rose Creek
Wolves reluctant to leave pens
$750,000 in 1995
USFWS cut funding in 1996
Charities made up the shortfall
1996 Fort St. John, BC
-40 degree temps, deep snow
53 wolves were captured in 12 days
4 groups to YNP (6,5,4,2)
20 to Idaho
$267,000
1997 Montana Pups (10)
86 YNP wolves in total
9 packs
Reflections
All wolf descendants only from reintroduced wolves
2005 genetic analysis
Confirms extirpation of wolves
The effects on hunting and livestock will always be an issue
Remain vigilant
Requires management
*The Ecology of Large Mammals in Central Yellowstone” (Garott)
*Yellowstone's Wildlife in Transition
Chapter 3
Essential Biology of the Wolf
Jack of all Trades, Master of none
Widest distribution
All animals, alive, and scavenged, and plants
Exemplifies a generalist
Long snout, moderate bite force
Better sense of smell
A large variety of teeth
The wolf is kept fed by his feet
Concentration of leg muscles near the body
Digitigrade posture
Speed and distance
1-5 mph walk
31 mph run
10-20 miles on an average day
52 miles maximum per day
Hungry like a wolf
Fasts for 10-17 days
Potentially 67-117 days
Fast recovery
7%-8% over 2 days
Live fast, Die young
Knowledge of Life history is a key to ecological understanding
Generation time
Pups born in dens in mid-April
63-day gestation
Nurse for 2 months
Pups moved to rendezvous site at 2-3 months
4-5-month-old pups follow adults
Fully nomadic at 6 months
Gain 80% of weight in 1 year
Burst speed plateaus, leading to the conclusion that the additional 20% is fat
(Bobby thinks this just means it’s non-leg muscle; bone density, biting muscle, and mostly fat)
Mass growth ends at 5-6 years old
Males and Females grow at the same rate
Males 4 cm taller and 7 cm longer
6-8 month growth period
661M 153 lbs, the heaviest wolf ever at 7 years old
Reproduction
Numerous factors affect success
#1 Female body size
More puppies and more survival
Average 4-5 pups
1-3 Survival
Females breed in the third season
Aging
Males peak at 5
Females peak at 6
Reduced reproduction at 4-5 years
Median lifespan 6 years
Resilient species
Rapid growth
Early maturation
High reproductive rates
Short generation time
Contributed to Ice Age survival
Chapter 4
Ecology of the Pack
First natural pack 2M 7F
Leopold pack
7 Liters
Archetypical
Formation of a pack
The pack structure is flexible
What is a “pack”?
Centered around a Male/Female bonded pair
All associated wolves that spend the winter breeding period together
Lone wolves
Temporary status
Dispersing animals
10-15% of population
36 packs in Park History
5 classic formations
30 group dispersal or pack-splitting events
Pack splitting
Occur when large numbers of breeding-age adults occupy a single pack and generate friction within the pack
Group dispersal (most common)
2 or more wolves leave a pack and join with other wolves
Same pack mates vs. pack mating
Group dispersal represents a less risky survival strategy
Pack Longevity
The outcome of demographic processes
Longer-lived packs had better pup and breeder survival
Pack Size and Composition
Estimated via mid-winter counts
2-37 wolves per pack
10 wolf average
8 pre-puppy average
Pack size unrelated to prey size (2003)
Conflicting results (1993 and 1998)
Typically 50:50 male-to-female ratio
Can skew strongly
⅓ of the pack are puppies
Breakdown
3-4 yearlings (10-24 months)
4-5 prime-age adults (2-5 years)
1 old adult (6 or older)
Relatedness
Most wolves' first or second-order relatives
Alphas unrelated
Hierarchical Relationships
Idea of alphas from captivity
Countered by parents being dominant over offspring
We still assign alpha status
Dominant behavior
Primary breeders
Direct the pack activities
New Categories
Dominant breeders
Subordinate breeders
Subordinate non-breeders
Activities mainly directed by dominant wolves, subordinates can lead in “complex packs.”
Leadership is shared labor, but females have greater power
Subordinate labor division
Females directly care for pups
Males' food acquisition and defense
Mating
Long held to be monogamous
25% of breedings are “plural”
Evolutionary history of polygamy
Sexual dimorphism
Male competition
Breeding strategies
Why natal philopatry
Increased survival
Interpack opportunities
Territory inheritance
Kin selection
Constraints on mates and territory
“Wolf breeding strategies are borderline voyeuristic.”
Inbreeding rare
Except in isolated situations
Recognize familiar individuals
Females more likely to inherit breeding status
Moves toward matrilineal
Males gain breeder status mostly by dispersal.
Different strategies reflect the different costs and benefits of males and females.
Consequences of cooperation
Midwinter breeding season
61-63 day gestation
Late April birth
Emerge in late May
Weaned at 5-8 weeks
How is a mother wolf's performance impacted by her pack?
Litter size increases with pack size
Peak at 8 adults (6 pups)
Declines after
Pup survival increases with pack size
No limit
The number one factor in pup survival is the number of adult males
Better-fed mothers and young
Increased safety
Multiple breeding females strongly reduced puppy survival
An exception is 2000’s druids with 20 of 21
All this creates pressure for females to maintain a beneficial sex ratio
This rarely happens
The Adaptive Value of Wolf Society
Maximized “inclusive fitness”
Take into account shared genes
Why are wolves in packs?
Territory defense
Group hunting
Food defense
Kin selection
Cooperative breeding
Chapter 5
Territoriality and competition between wolf packs
First documented by Adolf Murie in 1940 in Denali National Park
Reaffirmed by Mech
Since 1995- 2020
97 wolves killed by others
6 times more than any other cause
Measuring Territoriality
Aggression relating to relationship to place
At ease with conspecifics (elk) (0)
Fights account for major mortality (wolves) 10
Society depends on providing for their immediate family and ingroup. The greatest similarity to people
Territoriality in Yellowstone
Avoidance
Scent marking (smell 1000x times better than humans)
Howling
Avoided by smaller packs
Sound caries 15km
Direct Interpack Aggression
444 aggressive chases observed
20% physical attacks (88)
5% led to death
Only 10% of interactions were aggressive
Most at night
Aggression varies with population density and overlap
Wolf Densities
100/1000 km Yellowstone
40/1000 km Minnesota
3-10/1000km Denali
Recent densities 40/1000km
Competition influenced by prey abundance
Elk from 20,000 to 7,500
1995- 2003
Elk migration brings wolves into competition
The disease may affect interactions
Mange increases scavenging
Increases aggressive interactions
Individual personalities are also at play
07-08 2 males bred with several young females, chased off 25 times
Seasonal Aggression
Winter leading up to mating means increased aggression
1-week estrus
Corresponds with peak aggression
Testosterone drops after breeding season
Denning early creates a stationary target and a greater disadvantage
13-day siege recorded, 2006 Slough Creek
Used by many packs
Sigh of 3 of 8 den attacks
One of few dens visible from the road
Spring attacks are particularly deadly as some packs are whole and others are denned and dispersed
Mapping
Started low and increased rapidly
16 packs max in 2004
2009 “equilibrium”
No shift in density
Subtle pack changes
Individual Behavior
Males increase aggression with age
Females stable aggression
1.6% per wolf aggression (?)
Gray wolves are more aggressive
K locus, melanocortin system
Increased cortisol levels
Immune system function decreases perhaps
Agate Creek Pack
An inordinate number of alphas
Why?
Attacks on Individuals
Pups least likely to be attacked
Breeders often targeted
Breeders most to lose thus most aggressive animals
Packmates help draw wolves away 29% of the time
50% effective
Conflict Resolution
Larger packs mean greater chances of winning
20% larger = 80% chance of winning
Older animals (6+) punch above their weight class
2.5:1
Rarely are old animals driven out of the pack
113M raised pups after his prime, so took over as alpha
810F Junction female with injury was cared for by a pack
Can seem counterintuitive
Don’t kill old puppies
Doesn’t signal a new estrus
Adopting adults
Group dispersal common
Avoid the lone wolf phase
Immediately control territory
Insulate from the death of the breeder
Conclusions
Dynamic
Wolf density
Prey abundance
Pack size and composition
Individuality
The most successful wolves are the ones that best live with many others
Wolves live for today
“I’m here, It’s today, so it’s a good day”
Chapter 6
Population Dynamics and Demography
2007 94 wolves in 8 packs
2012 34 wolves in 4 packs
3 Disease outbreaks
2 Recoveries
Why?
Elk is down 75% from all-time high
Food is the key regulator of populations
How?
Increased productivity
Increased recruitment
Increased longevity
Decreased dispersal
Decreased conflict
Undulate Biomass Index
In the absence of human-wolf conflict, density is set by prey biomass
Converts prey to common units
1 Elk = 3 Deer
4 Vital rates
Birth
Death
Immigration
Emigration
Alternative hypothesis
Intrinsic regulation
Intraspecific strife
Which vital rates matter most?
Colonization Phase
2 packs bred in the acclimation pen
Rose Creek (8)
Soda butte (1)
Few illegal killings
Rapid population growth
1995 14-17 elk per square km in the northern range
Subsystems
Northern range =10%
Park interior = 90%
Different ecosystems
Sage vs forest
Hydrothermal
Elevation
Snowfall
2020: 35-98 wolves per 1000 km in the northern range
10-20 wolves per 1,000 km in park interior
Phases
Colonization phase
Rapid growth and die-offs
Saturation phase
Stable population
What’s next?
Reproduction
“Fast life history”
Productivity, plural breedings, recruitment, young breeding age
Stats (280 liters)
4.7 pups per litter
1-11 pups per litter
25% plural breedings
Leopold pack 25 pups in 2008
Less plural breedings in the interior
Also less well-studied
Less plural breedings now
The difference is food abundance
High pup survival: 70-90%
<30% after distemper
Most pup mortality in the summer
Differs from other wolves
Survival factors
Female size
Female coat color
Female age
Pack size
Population density
Survival
80% of mortality human-caused
Yellowstone rare place where natural mortality dominates
40% wolf on wolf
9% wolf on prey
Short lives result when you are killing things bigger than you are with your face”
4 Life Stages
Puppy (<12 months)
Yearling (12-24 months)
Adult (2-6 years)
Old Adult (6+ years)
Median age 5.9 years
Natural survival pattern
Most packs have at least one old adult
Beneficial to pack survival
Wolf can live 11-15 years in the absence of people
Survival Rates of 70%-80% per year
Unrelated to prey abundance
Mostly unrelated to the disease
Except 2008 CDV
Most adults die in winter
Dispersal
The most difficult vital rates to quantify
May buffer population swings
Different dispersal strategies depend on:
Age
Sex
Ecological conditions
Males tend to disperse
Females are philopatric
>50% of dispersal wolves are 1-3 years old
Decline after age 2
Nobody knows why some wolves are tolerated and others aren’t
Maybe personality?
Most dispersal in late fall and winter
Near breeding season
Population density inversely correlates with wolf dispersal
<8% since 2008
Accessed population via howls and scent marks
Often make short excursions before deciding to leave or not
Dispersal doesn’t mean immigration
Very low Immigration into Yellowstone
“Yellowstone Fortress”
Females disperse when males have long breeding tenors
YNP males have 2-3 year typical tenor
Not long, females stay longer
Outside of the park human kills keep wolf densities low and encourage M/F dispersal
Group dispersal also unique to YNP
Low human mortalities
Higher population density
Modeling vital rates
Math to show which rates are most important
Important to help us understand exploited populations
Demographic models rare for wolves
Stochastic and deterministic models
Deterministic rates stayed the same
Stochastic rates varied within bounds
Take-aways
Adult survival strongest correlate to population growth
#1 yearling survival
#2 year old survival
#3 Old adult survival
Biomass determines wolf densities
Adult wolves higher survival rate than puppies
Survival is density-dependent
Intrinsic regulation
Recruitment is prey-dependent
Extrinsic regulation
Wolf territoriality keeps the population lower than the individuals
Chapter 7
Genetics
39 chromosomes
Genotype vs phenotypes
Hot Springs to Wolf DNA
1960’s Thermus aquaticus
Heat-stable enzyme Taq polymerase
Allowed rapid DNA replication
1989 molecule of the year
PCR and Kary Mulis Nobel Prize
Wolf DNA from all founders collected
All collared wolf DNA collected
Wolf Project has vast amounts of data
Research
Microsatellite loci
Relatedness
Population dynamics
Single nucleotide polymorphisms (Snips)
Reveal recent adaptations
Preserved region over evolution
Genome sequencing
Deep answers to questions
See what genes expressed in relation to ecological conditions
Population structure, pedigree, coat color, natural selection, life history
Pedigrees to population structure
Pioneering genetic study of 200 wolves
26 microsatellite loci
Parentage, pair characteristics, pack structure
High-level diversity
Low inbreeding
Increased diversity
Large founding population
3 distinct founding populations
Social animals with low inbreeding
YNP wolves part of GYE wolves
Genetic connectivity is a primary stipulation for delisting wolves
vonHoldt found this true
21 migrants in the first 15 years
“Genetically effective dispersal”
5.4 wolves per generation
Uneven dispersal
No immigration into YNP first 10 years
Have been documented since
Founder of 8-mile pack
Work has consequences for future endangered species reintroduction
Conservation genetics
Life histories to evolutionary histories
Ancestry of canids
Similar to commercial tests
North American canids have been exchanging genes for 100s of generations
Represents a unique species complex
Yellowstone wolves true gray wolves
Western coyotes are true coyotes
Eastern wolves (Canis lycaon) and Red Wolves (Canis lupus) are unique mixtures of two
Domestic dogs around for 40,000 years
Genetic changes occurred
Similar to human hyper-gregarious behavior
William-beuren syndrome
Potential link to domestication
Heritability
Yellowstone is unique
Well studied behaviors
Well studied genetics
Well studied ecosystem
Case Study on Aggression
Aggression is 28% genetic
Gene expression
Means of adaptation over the lifetime of an individual
Wolf DNA and RNA tell us how a wild genome functions
Epigenetics
Chemical modification of DNA regulating how, when, and where genes are expressed
Methylation (CH3) to cytosine
Turn off expression at the site
New genetic technologies allow us to see if genes are methylated
Deeply conserved epigenetics
Epigenetics of aggressive dogs
RNA- instructions for making molecules
RNA reflects current gene expression
Age, rank, sex, coat, and mange affect gene expression.
No correlation unlike humans
Age #1 indicator of epigenetic expression
Similar to elderly humans
Wolves and Genomics
Genes diagnostic of wolves
Probe the canine admixture
302M “Cassanova”
Father to the first confirmed mixed puppies (?)
Chapter 8
The K Locus
Adolf Murie 1940’s
Used color as an ID
Speculated that color variation due to interbreeding with dogs
An equal number of black and grays
Coat color genes senescence
Turns to silver and white fur
25 gray 16 black wolves reintroduced
50:50 color balance after 10 years
Color Genes and Function
Pleiotropy: genes that affect multiple unrelated aspects of a phenotype
Eumelanin and Pheomelanin
Modulated by 2 genes
Agouti and MC1R
Dogs in contrast have 7 genes for coat color
CBD103 or K Locus
3 nucleotide deletion
K(B) = Black (dominant)
K(Y) = Gray (recessive)
K Locus source
KB arose in dogs
Transferred to wolves
“Selective sweep” in wolves
Black coats incurred a strong advantage
Leaves low genetic variation
Neighbor-joining tree construction
Grouped Ky separately
Grouped Kb together
Kb found to be younger in wolves
Thus showing the dog-to-wolf transmission
Geographic Origins
Capture array
Originated in NW North America
The closest Kb haplotype is in Labrador Retrievers
Kb originated 121,000 ybp
Transferred to wolves 15,000 ybp
Selection for the K Locus
Heterogeneous wolves have the best Darwinian fitness
A homozygous gray close second
Homozygous black very low
5% of wolves in YNP KbKb (homozygous black)
Dismiss the adaptive camouflage hypothesis
Balancing polymorphisms
Keep both phenotypes around
K locus is also a beta-defensin gene
Opposites attract
Positive assortment: seeking a mate similar to one's self
Negative assortment: seeking a mate dissimilar to one's self
Increases genetic diversity
Decreases inbreeding
64% of wolves breed with opposite coat color
Non-random assortment
Only mammal is known to negatively assort
Only single gene color polymorphism in vertebrates
The coat color mix is possibly totally explained by negative assortment
No selective advantage (maybe?)
No mechanism for it
Doesn’t exclude heterosis
Effects on behavior
Gray coats have 25% greater pup survival
Black coats may divert energy to the immune system and away from ovulation and lactation
The system demonstrated in other animals
Black wolves are less aggressive than other wolves
16+ year study
Gray wolves are 1.5 times more likely than black wolves to chase rivals
Opposite the findings in other animals
K locus secondary to nurture
Grays have higher basal cortisol levels
Decreased immune function
Immunity
CBD103 (K locus protein)
Beta-defensin antimicrobial peptides
Released by skin, kidney, and brachial
No direct evidence of increased wolf health!
Canine Distemper Virus (CDV)
Sarcoptic mange
No correlation with infection rate, severity, or recovery rate
Surprising due to B-defensin activity on the skin
Canine Distemper Virus
It is a virus
Affects the respiratory, gastrointestinal, eyes, and nervous system
Integrative model
Black wolves increase with disease frequency
Disassortative mating is favored when disease intervals are less than 6 years apart
P.W. Norris recorded black wolves in YNP in 1881
Chapter 9
Infectious Disease
“Reintroduction didn’t bring back all trophic levels, wolves were disease free”
Major diseases
Distemper
Mange
Cestodes
Nematodes
The study of:
Use antibody and PCR tests
Prior to reintroduction coyotes and foxes carried parvo, herpes, and distemper
1997
100% Parvovirus
61% Adenovirus
65% Herpes
Proved very susceptible to disease
Parvo
Contact with feces and nasal excretions
Can survive up to 6 months outside of a host
Viral shedding for up to 30 days
Averages are not useful
VDV absent for many years but nearly 100% in others
Average is 37%
Epizootic nature of CDV
Enzootic persists in the population
Herpes, parvo, adenovirus
Epizootic persists outside of the population
Strong focus on CDV due to its effects on the population
Echinococcus: canine host for reproduction, ungulate host for growth and development
Tapeworm (yummy)
CDV
1994: First outbreak, thought to be parvo
Similar population decline on Isle Royale
2005
Coyotes with tremors spotted
Pitted tooth enamel
Symptoms of high fever
Lethargic pups
Death within 2 weeks
Morbillivirus genus (scary bleed-out-of-your-eyes shit)
measles, phocine, distemper cetecian, morbillivirus, rinderpest
Capable of infecting many carnivore species
Symptoms
Fever
Nasal and ocular discharge
Respiratory and GI involvement
Impaired immune system function
Neurological impairment
High mortality in naive victims
Pup Survival
70% in non-CDV years
22% in CDV years
Adult Survival
83% in CDV years
77% in non-CDV years
“No significant difference”
Resulted in a 30% population drop
Like measles, CDV has a minimum threshold on which to subsist in a population, it cannot survive year to year in the GYE
Sarcoptic mange
2007: 2 Mollie wolves first to be found inside of GYE
2002 saw mange outside of GYE
Introduced in 1900 to kill coyotes
200 coyotes were live captured and then set free
Sarcoptes scabiei
Mites
Burrow into the skin and produce an allergic reaction
Scratching leads to hair loss, skin damage, and secondary infections, lowered body conditions
Highly visible symptoms
Class 1 - 1%-5% hair loss
Class 2 - 6%-50% hair loss
Class 3 > 50% hair loss
Unique infections
Months greater than a year are considered chronic
Depends on immune function of animals
Likely enzootic
Here to stay
Mange predisposes wolves and coyotes to anthropogenic death
Populations' stable interior and northern range
North has 1.5 times more variable growth
Interior less impacted by the disease
Lower densities
No direct evidence that disease plays a role in the spatial structure of wolves
Yet
Sociality and disease
Faster within groups
Slower to outgroups
Questions
How does the host social organization constrain or facilitate the speed of a pathogen?
Are the effects of pathogens modified by the hosts' social behavior
Answers
It varies by pathogen
Increases in directly transmitted infections
Ex: distemper: short infection intra-pack spread increases
Ex: mange: longer infections lead to population-level spread
Living in packs benefits wolves
Better pup rearing
Better hunting success
Better territory defense
Better carcass defense
Increased disease survival
Future direction and conclusions
Diseases logistically hard to define and document
Trophic cascade of pathogens
“Healthy Herd Hypothesis” Wolves help with CWD
Incredible at sensing and selecting infected animals
Chapter 10
How we study Wolf-Prey Relationships
Early Techniques: stomach contents, tracking to kill sites, radio collar tracking (now GPS)
Every study since 1950 looks at prey!
1958 Allen, Isle-Royale
1959 Dimlot, Algonquin Park
1968 Mech, Northern Minnesota
Radio collars essential to ongoing research
Received criticism for being “less natural”
“We study nature so we can preserve nature”
Data over opinions
18-year study on wolves in the Yukon
“Does killing wolves increase game?”
Yes caribou and moose
No on sheep
Do so all low densities
Aerial gunning is a poor investment
Long-term studies allow us to answer questions we didn’t know we had and generate an understanding of the system versus answering a single question
Winter Study
30 days from November to December and 30 days in March
Studies seasonal vulnerability of prey
How often do wolves kill?
What do wolves kill?
Species
Age
Sex
Condition
By November 1995 ground observations were added to the study
Behavioral info
Visited carcasses
Data Analysis
Minimum method
Kills divided by the number of wolves divided by 30 days
Kill interval
Days between kills
Abandoned those for the “double count” method
Measuring the difference in carcass detection rate to estimate how many are missed
Adding GPS data since 2004
Using the “triple count” since 2009
Analyzing elk
Teeth can be pulled for aging
Saw femur for condition
Metatarsal estimates body size
Chapter 11
Limits to Wolf Predatory Performance
How do wolves kill their prey?
This is a key source of myth and misunderstanding
Wolves are often unsuccessful on hunts
Prey must be disadvantaged for wolves to feed”
Old or sick
Often detected by smell
Skulls not evolved to deliver a killing bite like other animals (hyenas or felids)
The skull is too long and that decreases the bite force
The jaw is not properly stabilized for those forces
No sharp claws
Age, body size, and social behavior determine hunting success as well
Assessing hunting ability
Described the “foraging state” of wolves in 3 stages
Attacking
Selecting
Killing
2-3 year olds are the best hunters
Fluctuations in the age composition of a pack affect ungulate populations
Big wolves generally are better hunters
Success rate decreases with prey size
Pack size does little to offset age and size constrictions
Packs of 4 wolves are more successful than fewer
No advantage for greater than 4 wolves
More are usually just freeloading wolves
Avoiding injury
Join the hunt just to be close to food
The theory says cooperation should go up in large packs hunting large prey
Bison hunting
3 times harder to hunt (lesser success rate)
Large, more aggressive, more dangerous, and more time-consuming
Success with 9-13 wolves and some evidence that the trend continues
1 vs. 1 A wolf has a 2% chance of killing an elk
The main advantage of the large packs is fights with other packs
Effects on Prey Group Size
Overcome shortcomings by targeting small, vulnerable animals
Maximize encounter rate (60-80 minutes)
Fleeing signals weakness
Large groups more likely to have vulnerable individuals
Hunting success rates maximize at herds near 20 individuals
Conclusions
Wolf biology precluded it from being a killing machine
Exaggerated virtues and vices
Chapter 12
What Wolves Eat and Why
Any Predator
What is abundant
It’s ability
The most profitable prey
Background
“Use” - how often an item appears in the diet
“Availability” - frequency of encounters
“Prey selection” - choosing one animal over another
Prey taken vs prey available
Larger numbers than expected are the prey being selected
Adolf Murie first to discover the vulnerable prey hypothesis
Wolves prey mainly on 8 ungulates
Animals migrate and this affects the availability
Use of ungulates by wolves
5,788 recorded wolf kills over 22 years
Divided into 4 regions
Divided into winter or summer
Elk always primary diet
Fewer elk in winter when they leave the valley
Given a choice wolves prefer elk
Why?
Vulnerability
Predator body size
Seasonal Variation
Marrow studies
<40% marrow fat = poor condition
40%-70% = fair condition
>70% = Good condition
Species
Highest percent bison in spring and fall (10%)
7% - 12% deer in summer
Elk age, sex, and condition recorded
Kill calves after they emerge from hiding
65% of the wolf diet in the summer
45% of the diet in the fall
30% elk calf survival rate
Period of risk ends after 1 year
Wolves average kill is 14 years old
Hunters average 6.5 years olds
Little change over the last 20 years
Killed after making genetic contributions
“Doomed surplus” was coined in 1946 by Errington
Compensatory vs. additive predation
Adult males 37% in winter, 12% in summer
Environmental conditions
Kill more males in poor summers
Antlers as defense
Select antlerless males in better condition vs. poorer males with antlers
Elk vs Bison Selection
Wolves continue to select elk
At odds with prey switching idea
Wolves Scavenging Bison
Changes the equation
Underappreciated scavengers
25% of the diet by biomass is scavenged
Conclusions
Elk vulnerability is a key
Scavenge bison when available
Directly tied to bison abundance
Wolf Predation on Elk in a Multi-prey Environment
“It does draw attention”
When and how much predation stabilize ungulate abundance?
Any factor that can reduce abundance is “limiting”
Independent vs. stochastic models
Factor adjusting abundance is “regulating”
Returning to equilibrium
A positive relationship to abundance
Competition for food results in boom-bust cycles
Predation
Is predation linked to abundance?
Positive or negative
Annual predation rates
Pre-reintroduction, Post-culling (1968- 1994)
Elk regulated at 20,000
Decline in fecundity at that density
“Wolves for Yellowstone” modeled elk number decrease following reintroduction
Follow-up studies disagreed
Complicated
YNP elk more wolves (bison)
MT elk less wolves (deer)
MT 2x more elk
Kill rates
The rate at which predators kill prey per unit time
Number or biomass
The most important factor is prey abundance
“Functional response”
Search time
Capture time
Type 2 response (destabilizes prey)
Type 3 response (stabilizes prey numbers)
Wolves functional response differs seasonally
Type 3 occurs when prey switching is possible
Wolves have not yet switched to bison in northern Yellowstone
Some switching in the west
Does the killing of wolves slow the prey-switching behavior of wolves and potentially lead to a drop in the elk population?
What are the effects of the bison cull?
Elk abundance is the main driver of the functional response type
Elk population growth unrelated to the kill rate
1997- 2008 study
Predation rate = kill rate + predators + prey abundance
Wolf and Elk Abundance
The numerical response
How prey respond to predator numbers
Predator numbers don’t always track with prey
Wolves in proportion to Old Moose (IR) (?)
Do wolves level off due to intraspecific conflicts before prey
Yes in northern Yellowstone
Hypothesizes elk abundance was a key factor in wolf abundance
Type 3 response 200-2016
Types 1 and 2 also fit
Wolf Predation Rate
Wolf predation rate uncorrelated with elk population
Differs from Isle Royale and Banff
Weather and human harvest caused the decline in the elk population
Vucetich 2005
Wolf predation on recruited elk (>5.5 months old)
Neonate predation compensatory
Predation rates 1.8% - 9.3%
Very low until 2000 (3%)
9,700 northern range elk is the tipping point for predation rate (7%)
Effect of wolf predation on elk abundance
3 reasons this is difficult
Multiple sources of mortality
Changes in Elk: Wolf population
Incomplete data
Wolves outside of YNP
Interior wolves
Summer and winter interior migration
Wolves have a positive effect on elk at 5,000 - 10,000 individuals
Seeing equalizing effect now
Will equilibrium hold?
Banff agrees
Madison- Firehole agrees
Chapter 14
Population Dynamics of Northern Yellowstone Elk, Post Wolf Reintroduction
Yellowstone National Parks Elk Herd
Wintering within park boundaries
Concerns vary over time about herd size, too large vs. too small
1800s market hunting
Elimination of predators
1920-1968 Elk culls
1969- 1994 Ecosystem damage
Agricultural damage
Allowed late-season elk hunts in Montana
December - February
Targeted cows
Average 1000/ year in winter
Average 500/ year in fall
19,000 elk in January 1994
Hunting alone couldn’t control the population
16,500 in December 1994
775 hunted
Wolves blamed
Didn’t arrive until February 1995
3,915 in 2013
Effects of Wolves on Northern YNP Herds
Reintroduction justified as part of natural management philosophy
Elk counts are not 100% accurate
Stability bias
We always miss elk
9%-30% in a good year
35%- 51% in “bad” year
Wolves contribute, how much?
Wolves are low-probability hunters of a wide variety of prey
Hunting success rate <20%
<10% on adults
Selective hunting determines age distribution
50% of a wolf's diet are calves
85% of adult females >10 years
Average 13-16 years
Average 9 years old in Madison River
Harsher winters and shorter lives
Chances of being killed by a wolf
<2% from ages 2-14
> 5% from hunters age 2-14
Least likely to kill most fertile elk
Questions about elk calf survival
Wolves prefer calves 40% - 60% of the diet
14%-17% of calf fatalities wolf related
Calf survival 90% over winter
16% on severe winters
Bear predation up from 25% to 60%
Similar for cougars
Does an increase in predation reduce winter kill?
Wolf predation appears additive
No clear causation just correlative
1995-2002
5.7%- 18.7% elk were killed by hunters
1.8% - 6.2% elk were killed by wolves
Discontinued late-season hunts in 2009
Currently, 50 antlerless animals per year are harvested
1.5% of winter count
Each new predator decreases prey abundance step-wise
Are predators synergistic or anti-synergistic
Speculation on the role of bison competition and luring wolves away?
Climate is the ultimate impact
Summer temperatures and precipitation
Forage quality, body condition, and ultimately survival
Climate change exacerbates concerns
Conclusions
No science will solve the elk debate
Never before has the elk population looked like it does now
Stakeholders differ in view of what it “should” look like
Chapter 15
Restoration of Vegetation
Trophic cascades are indirect species interactions that originate with predators and spread downward through the food web
Darwin and Leopold talked about this before the term was coined
Effects in YNP largely unpredicted
Ecology of deciduous vegetation on YNP’s northern range
2 vegetation types
Aspens
Cottonwood and willow
Combined 5% of landscape
High biomass and diversity
Low replacement rate and growth rate
The trophic dismantling of Yellowstone
Deciduous trees before reintroduction
Near extinction of all predators
Massive spike in elk population
Tree recruitment was normal from 1800-1900
Tree ring analysis confirms
Lack of recruitment due to elk recognized in 1939
Elk not lack of fire, limited aspens
Twice as many aspens in 1872 cs 1995
Hypothesis: Fires produce enough new growth to overwhelm elk
Tested and negated after 1988 fires
Decline of beaver willow state and emergence of elk-grassland state
⅓ of streams had beavers precontact
Decline documented in photos
Decline in beaver
Increased stream downcutting
Lowered water table
Decreased recruitment
Positive feedback
Berry bushes are also affected
Managers respond
Capture and cull major management technique
12,000 in 1950s - 5,000 in 1960s
Elk concentrated in YNP in the 1980s
High grazing pressure
1968 Elk Cull stops
1976 Montana institutes elk hunt to reduce agricultural damage
20,000 elk in 1980’s and 1990’s
Increase in winter kill
Ecosystem response to carnivore recovery
Predictions of elk decline of 30%
Not enough to cause cascading
Aspen and Willow response
Elk ate 90% of aspen sprouts
Currently 30%-60%
Willow relied more on local factors
Water table mainly
Height increase post reintroduction
Aspen 3.2 times
Willow 1.7 times
Increased genetic diversity for both
14x and 13x respectively
Aspen study shortcomings (a lot made of these in recent times)
Measure 5 tallest aspens as a sample of the “leading edge”
No measure of stand structure or height distribution
It is a good indicator of the stand survival rate
Plants over 200 cm out of browse range
Regeneration corresponds to the end of a multi-year drought
2000-2007 Palmer drought index numbers
Recovery began during the drought!
Elk at a similar population in the 1950s but no plant recovery
Culture of fear hypothesis
Changes in distribution
80% of elk now winter outside of the park (formerly 0%)
More elk in the west than in the east
Water table willow experiment
Exclosures limed browser
Simulated beaver dams raised the groundwater level
From 121 cm below the surface to 33 cm below
Fastest impact when combined
Confirms water table is the most important
Cottonwood responses
Nearly all >25 cm diameter
20% decrease since 2001
Bank erosion, disease, bison, beaver, wind
Seedling establishment
Bare wet sediment
High soil moisture
Low herbivory
2012 survey
2,300 saplings per km (upper Lamar)
3 saplings per km (lower Lamar)
The same quality and quantity of habitat
Alder and Berry-producing shrub response
Taller
More fruit
Especially serviceberry
Synthesis
No woody plants taller than knee height in the late 1990s
3 patterns of change
Taller woody plants in some areas
Changes vary by browsing and groundwater
Bison have taken over browsing in some areas
Effects muddled by hunting increase and growth of bear and lion populations
What does vegetation recovery look like
Increased species heterogeneity
Increased age and size make up
Aspens may never be fully restored
Climate change
More study needed
How can we revert to willows and meadows
Increase willow growth rates
Fastest growth with the most water
1 colony along Lamar in 1995- 20 in 2015
Still considered too low
Secondary trophic effects
Changes in hydrology
Incised streams need beavers to grow willow, beavers need willow to live
Vicious cycle
Predators change elk behavior
Matter of debate
Rapid changes with high populations (in favor)
Weak and inconsistent evidence (against)
Changes happened simultaneously
Why was no similar change in 1960s
Duration? Predators?
Has climate change affected growth?
No
No significant difference in 20 years
Exclosures erected in the 1950’s and 1960’s
The northern range is warmer and dryer over the long term
Changes possible
Other trophic cascades
Yes 10 spots in the Rockies
Also Wisconsin and Minnesota
Prospects
Beaver, bison, and disease
Beaver needed to bring back willows
Bison now dominate ungulate
Increased soil compaction
Increased streambed collapse
Increase forage consumption
Fires are a resetting factor
Disease
History of distemper
Parvo
Chronic wasting
Plant disease
Cytospora chrysosperma
Canker causing
Spread by sapsuckers
YNP is still an island
Increased role for cottonwood and willow through time
Chapter 16
Competition and coexistence among Yellowstone meat eaters
Wolves relation to other carnivores
Scavengers
Bear and cougars
Significant and underappreciated
Communities structured by carrion
Increased competition
Underestimation of the scavenger effect
Interspecific competition
Between species
Exploitative competition
Reduction in species rate of acquiring prey
Ex: Bears eat most elk calves
Mechanism
Kleptoparasitism
Active avoidance
Intraguild predation
Scavengers
Conventional view: negative
Increased competition
Finding: Wolves provide reliable food sources
Not available for weasel badgers, bobcats, martens
Too high mortality risk
100s of invertebrates
How do scavengers locate carcasses
Coyotes follow tracks
Ravens follow wolves and key off activity (in question)
Magpies do the same
Golden eagles scavenge cougar kills
Bald eagles scavenge wolf kills
Differences are habitat-related
Bird killing is infrequent but does happen
50% coyote population drop in 1999
7% coyote death rate (per year)
Decreased over time
With wolves, winter severity became a secondary factor to elk survival
Scavengers prefer medium wolf packs
More kills
More leftovers
Less carrion, better temporal distribution
Spread through winter not just end (what happens with winter kill)
“Temporal subsidy” provided by wolves
Time feeding x feeding rate
Captive mammals
Birds peck per minute
30,000 lbs of carrion
Hunters #2 carrion provider
Differs from wolves
Increased ravens and eagles
Decreased coyotes
Coyotes consistently hunted outside of the park
Gut piles: 350 ravens, 50 eagles (per fucking pile!)
Dampened rave population fluctuations
Only 1 study found an increase
Pre: post raven numbers
221.5 plus or minus 37 (after)
314 plus or minus 102 (before)
Climate effects
Shorter winters mean decreased winter kill
Wolves buffer these effects
Grizzly benefit the most
Wolf kills
Increased soil nitrogen
Increased plant growth
Bear essentials: an omnivore's quest for meat
Poisoned along with cougars and wolves
Remote and popularity saved them
Meat is preferred but secondary food
YNP more/ most carnivorous grizzly anywhere
45% of the female diet (0% in the northern continental divide)
80% of the male diet (33% in the northern continental divide)
*** These numbers differ from the YNP Grizzly Ecology book***
Bears ate 35% of adult ungulates
Rare for wolves to defend a kill
Commonly chase bears away from den sites
Wolf vs. bear in GYE
6 COY, 1 yearling grizzly, 2 adult females
2 black bears and 2 cubs
0 wolf deaths
Wolf kill is standby food
Especially important with the decrease in whitebark pine
Bears use more wolf kills in the interior
Whitebark pine only loosely affects scavenging in the interior
Greater in Lamar, hayden, and pelican valleys
Increased bear density
Increased interspecific interactions
Bears twice as likely to take over cougar kills
Do interference, competitions, and kleptoparasitism affect wolf kill rates?
No- wolves linger longer on stolen kills
Elk calves (first 30 days)
70% bear
12% wolf
2% cougar
May- July 65% of wolf kills
Increased in areas without bears
Competition and kleptoparasitism increase cougar kills
Population-level fitness impacts exist between cougars, wolves and bears!
Wolves have a positive effect on bears
Bears negative effect on wolves
Cougars: Yellowstone's other top predator
Eradicated by 1930
Reestablished in the late 1980s on their own
Rapid population growth (10% per year)
Directly compete for elk
Different age and sex choices
Generally smaller elk
Choose calves all year
Wolves prefer older elk
No change pre- post wolves (there is an entire other book about this)
Southern YNP switched to deer as a primary food source
Attempted to minimize scavengers
Larger kill means greater displacement
Increased injury risk
Are there fitness costs?
Population-level costs?
Male home ranges dropped 50% in size post-wolf reintroduction
Greater overlap in home ranges
Increased stability
Consistent age-sex ratios
3F:1M
50% adults
15% subadults
35% kittens
Similar litter sizer and survival rate
Increased kitten survival
Decreased infanticide
Increased natural mortality
62% to 75%
Decreased intraspecific mortality
Increased interspecific mortality
Increased density
1.6 per 100 km to 3.9 per 100km
1 per 38 square miles to 1 per 16 square miles
West averages 2.6 per 100 km
Recently
Decreased wolves
Increased bison
Elk steady
Phase 3 cougar study
Noninvasive DNA
Similar density to phase 2
Triaxial GPS collars
Meat competitions past, present, and future
Today carnivores are small by Pleistocene comparison
75% of megafauna extinct
Decreased competition
Bears today compete with wolves more
Wolves rarely scavenge
Phase 3 shows decreased cougar displacement
16% vs 45% in phase 2
What is the cumulative effect on the elk herd?
Effects on scavengers, mesopredators, soil microbes, and invertebrates?
If predators coexist so can we
Chapter 17
Wolves and Humans in YNP
No pack is immune to human influence, variety of degrees
Park objectives for wolf management
Protect den and rendezvous sites
Prevent habituation
Educate visitors on correct behavior
Regulate viewing so as not to disturb natural wolf behaviors
Education and regulation
100-yard distance
No feeding
Temporary closures
Philosophy of wolf viewing
Most viewing from roads
Wolves respond less to humans on roadways
Increased natural behaviors
Limited “chasing” wolves
Wolf viewing off roadways usually displaces the animals
Short view times
Closures: dens and rendezvous
All “homesites”
Many homesites reused
Reuse means great:
Prey, cover, water, and safety
Dens closed until late June
~½ mile from den
No-stopping zones where wolves regularly cross the road
Human safety and wolf habituation
Visitors must maintain 100 yards
Cannot disturb wildlife
Habituation is the beginning of the end
Close encounters
Stand ground
Look big
“Wolf spray”
“The predator paradox” Shivik 2014
The least dangerous North American carnivore
20-30 dog fatalities per year
Wolf project tracks individual wolf behavior attempting to head off conflict
Low-level hazing is the first treatment
Yelling, honking, throwing rocks
Mid-tier hazing
Paintball guns with clear paint
High level
Beanbags, rubber bullets, cracker shells
Hazing 90% effective
Horses in wolf country
Attacks are very rare anywhere
Common in Spain….
Human presence is a further deterrent
2 encounters in YNP
No bites
Advice
Picket 1 or more horses
Leave mules free
Same advice for bears and moose
Temporary closures and carcass management
Roadies kills are removed to prevent habituation and vehicle strikes
Some moved to a safe distance
Placing yourself on the road for a crossing is a violation
Chapter 18
The wolf watchers
Watching has created famous wolves
‘06 females, 21M, 42F, 302M
Attention to individuals complicates management
Increase in public awareness
Creation of some misconceptions
Public support for wolves ironic as part of wolf eradication was publicly supported
Yellowstone is the best place in the world to see wild wolves
Infrastructure and landscape
Wolf Recovery follows a humanistic story arc
“Hero's Journey”
Wolf watchers
Loose knit
Open to all
Watch, learn, don’t interfere
Ambassadors and models
CUA holders
130 in 1995 →300+ in 2019
Global wildlife trend
28% increase since 2001
86 million people globally
$70 billion per year
Local economics
2016-2017 bobcat worth $300,000
In 2005 35.5 million locally spent on wildlife watching
(annual economic impact!)
2017 65.5 million dollars per year
Off-peak visitation is often supported by wildlife watchers
6 generations of ancestry
Challenges
Crowding
Vegetation damage
Habituation
Resources
Closures and education
35 wolf collisions since the restoration
Wolf Road Management program
Staff stops traffic for wolves
Hunting
Began in 2008
After delisting
Decreased pack success rates
Decreased wolf-watching success rates
Cannot coexist with ecotourism
Wolves become too wary of people
Pack instability causes population instability
Low quota around park established 2012-2018
Ecotourism
“Responsible travel to natural areas that conserves the environment, sustains the well-being of the local people, and involves interpretation and education”
Key is sustainability
Wolf watching doesn’t harm the animals
Yellowstones Mission Statement
“The NPS preserves, unimpaired, these and other natural and cultural resources and values for the enjoyment, education, and inspiration of the future generations.”
Chapter 19
Conservation and Mangement
“A way forward”
Examine and recommend a holistic approach to wolf management
Managing piecemeal will not benefit people or animals
Must work together
Different management philosophies
Diverse stakeholder values
Reintroduction and management background
‘'95-’97 Wolves released from Canada
Biologically recovered by 2003
Management turned over to states
Not inside of parks, on preserves, or on tribal lands
Hunting main management strategy
ID and MT hunts ‘09, ‘11-current
WY ‘12, ‘13, and ‘18- current
85% of their diet is Elk
Follow elk in harsh winters
Lured by hunters' gut piles
Values of Predators
Full spectrum of opinions
Tourism vs. depredation and hunting
Increased value and tolerance
Warming and development force elk to stay in YNP
Decreased hunting opportunities
Sport hunting and depredation increase tolerance
Hunting is key to the North American model of conservation
Economic and social benefits
Wildlife held in the public trust and responsibly managed
Balance consumptive and non-consumptive enjoyment
Contrasting wildlife management policies
State policies
Wise use and consumptive benefits
Provide a broad array of consumptive options
Hunting, fishing, trapping
Manage populations, food, and conflict
Licenses provide a budget along with federal excise taxes (minimal)
NPS
Preservation of wildlife systems
Currently
Maintain ecologic integrity and resilience
Maintain natural disturbance dynamics
Study the “biological baseline”
Wolf recovery and management in the Rockies
Predator control through the 1930s
YNP is more predator dense than ever
Predation and competition
Attacks
Guided by “Northern Rocky Mountain Wolf Recovery Plan”
3 goals
100 wolves in each state (outside of YNP)
The genetic flow between each
10 breeding pairs with 2 pups at the end of a season for 3 consecutive years
Achieved in 2003
761 wolves in 51 breeding pairs
Delisted in 2009 relisted in 2010
Delisted in 2011 relisted in 2014
Delisted in 2017 for the final time
Population growth
103 wolves in 1995
1,700 in 2009
2,100 depredation killings 1995-2009
Human-tolerant wolves in YNP
Unintended wolf-watching culture raised questions of habituation
4 million visitors per year are here to see wildlife
More vulnerable to hunting because of human proximity in YNP
Unrealistic visitor expectations
Research on Effects of Restoration
Effects on elk
Long-standing elk research
25%-30% of wolves are collared in a given year
Valuable collar data shared with all government agencies
Effects vary greatly
Migration, habitat, harvest, land use, weather, predator densities, management objectives
Wolf Hunting around YNP
(2009-2018)
9 seasons
39 wolves confirmed
5-7 more suspected
4.5% of the population taken in an average year
13 collared wolves
9 pups, 8 yearlings, 16 prime age, 6 old
55% of packs persisted post hunting
93% of unharvested persisted
67% had pups
77% of unharvested had pups
The average pack size was 7.5 wolves
11 in unharvested packs
6.2 in hunted packs
Loss of breeding females leads to disproportionate instability
Transboundary management paradigm
The same that is employed to manage wolves elsewhere in North America
Reduced quotas in districts 313 and 316
Areas directly abutting the park
No universal decisions
Unlimited harvest in the Banff area had no effect on wolf populations
Denali:
New area opened
1 female killed
No denning in the area
40% decrease in wolf sightings
Framework of Transboundary Management
Protect wolves from overharvest in areas adjacent to the park
Studies say harvest of 15%- 48% didn’t limit population growth
Colonization different from than saturation phases
Excess breeding vs. compensatory
Studies don’t show social structure
Higher-ranking wolves have a disproportionate effect
Limit hunts near YNP would leave more packs intact
Increasing viewing opportunities
Increasing pack stability
10-mile transition zone inside of national parks
9/11ths of packs use this area
6 packs have it as the entirety of their range
Refugee zones
No more than 20% of the