FW 458 Final Exam

• Martin 1984
• Blitzkreig hypothesis/ "Clovis first"
• Rapid settlement of Americans (12,900 yrs. bp)
• Guided with glaciers

• Exponential Population Growth
• N_t = N₀e^rt
• Colonization of empty habitat
• After strong reduction of population size (e.g. removal)

• Maximum growth that is biologically possible for a given species
• Scales to body size

• Density Dependence
• Closed popualtion with no hunting or predators growing exponentially
• Resulting in intraspecific competition
• Population density can affect both fecundity and mortality

• Logistic Growth
• dN/dt = rN (1-N/K)

• "Maximum population size that the environment can support"
• Often applied as a single-species concept

• Pregnancy rate (# of fetuses)
• Pregnancy rates don't decline until conditions are very bad
• Fairly stable for most of the female's life

average number of live births per reproducing female ("litter size")

• Fecundity
• Average number of offspring born for a given age/stage
• Tends to show density dependence faster
• Litter size shows big differences

• Recruitment
• Number of offspring that survive to "adulthood"

Number of individuals added to population

Logistic Growth is just one of population growth with density dependence

• Natality / fecundity lower
• Recruitment very low
• Mortality (particularly of juveniles) is high
• Individual quality/ condition is lower

• Time Lags
• Popoulation Cycles response to habitat quality

• Oscillations
• Trophic levels out of sink
• Unlikely

• Gestations time (# of individuals born reflects habitat conditions in the previous year)
• Long-lived species with high adult survival
• Population and habitat (vegetation) cycle differently
• Environmental stochasticity and predation
• Stronger = growth rates are higher, and population close to K

• Irruption
• The Kaibab Paradigm
• Permanent Habitat Damage

• Irruption & dampened oscillations
• Blacktailed deer on Angel Island

ICC & MSY (Stability Problem)

• KCC (equilibrium cc) & ICC (inflection cc)
• Two concepts of carrying capacity

• Relative Deer Density
• another CC concept

• Importance of different habitats for determining desired deer density
• Not all management objectives or human values will be met
• Helps compare deer populations in different environments

• Need estimates (or indices) of K in different habitats
• In absence of predation, require heavy harvest (both sex)
• - Not always possible/practical/socially acceptable

• any process that causes mortality or affects birth rates (affects the rate of population change)
• - both density dependent and independent

• Any process taht causes growth rate to decline as a population increases
• - density dependence

• Populations of herbivores are constrained primarily by plant availability, populations of predators are determined by herbivore availability
• - depending on forbs
• Competition dominant mechanism (intra and inter specific)
• Population increase competition increase
• Predator populations dependent on prey availability

• populations of predators control herbivore populations, which in turn limits the impact on vegetation (depend on Apex predator)
• predation dominant limiting herbivore populations
• population prey increases population of predators increase
• prey are not limited as strongly by intraspecific competition (e.g. lack of food)

• Competition for resources among members of the same species (food, water, den sites, shelter)
• Density Dependence
• Affect sex and age classes differently

• Concept of niche and resource partitioning
• Species evolve separated niches to reduce interspecific competition
• Stronger during times of limited resources

• One species improves habitat quality for another
• Ex.: bison grazing encourages growth of forbs and improves forage availability for pronghorn anatelope

• Increase in one species causes a decline in another even though there is no direct competitive interaction
• Ex.: whitetailed deer vs. elk, caribou, mule deer, moose
• (Cote 2005: deer competitively exclude bear)

• Numerical Response Model
• Change in predator # as prey increases

• i. predators regulate prey at low densities
• ii. predators cannot regulate prey
• iii. multiple stable states

Predators are killing prey that would have died anyway because of starvation, disease, etc.

Predators are killing prey that would have survived otherwise

Predator has an alternative and abundance food source and therefore will not be limited by prey populations

• expansion in density or distribution, or the change in behavior of a middle-rank predator, resulting from a decline in the density or distribution of an apex predator.
• Ex.: wolves, coyotes, pronghorn, forbs

• Harvest Management
• Harvesting the same number every year
• Two stable equilibria for any strategy other than MSY
• Forecast environmental variation
• Ex.: cougar in OR, black bear

• Harvest Management
• Harvesting the same proportion every year
• Forecast environmental variation

• rather than setting a number of animals that can be removed each year, fix effort
• season of a set length
• limited number of hunters
• population increases, kill will increase

• 1. Determine the status of the population
• 2. Define the goals of the management program
• 3. Establish a management strategy
• 4. Determine how well the goals were achieved

• McCullough 1990. (Black Box)
• Harvest small number of antlerless deer along with usual male harvest
• Harvest higher proportion of antlerless deer (later)
• Slowly increase
• Track sex ratio of the population
• Track age structureof the harvested population

• Harvest of females will increase to levels similar that of males
• sex ratio will move towards equality
• female age structure will shift to lower age classes
• harves of males will increase becasue of much higher recruitment of males and females.

• Extension of the harvest ratio population estimator
• Good estimates of sex and age ratios
• Good information on harvested animals (number and age)
• Estimates of overall male mortality rate

• Microbes in the gut are used to break down cellulose in the plant cell walls and convert it to usable form
• - Foregut fermenters (ruminants) x2
• - Hindgut fermenters (off shoot)
• - large animals = colonic fermenters
• - small mammals = caecal fermenters

• Have four chambered stomachs
• Fermentation allws herbivores to eat the structural parts of plants (leaves, shoots, twigs, buds)
• No multicellular animal can break down cellulose enqymatically

• Bacteria and protozoa are maintained in the rumen
• - cellulose broken down into volatile fatty acids
• - rumen is anaerobic, buffered by NaHCO₃ in ruminant saliva to keep pH correct
• - bacteria = 60 -90% rumen mass
• After fermentation, material moved through other chambers into "ture stomach" and into the small intestine for absorption

• maintained with a lot of water
• can't handle fast changes in diet

• length of time that material stays in the gut
• - longer passage time = more complete digestion
• larger animals have larger rumens and longer passage time

• Energy (fats, oils, protein, starch & sugars, cellulose)
• Protein (amino acids, ruminant have few AA's)
• Water (free, preformed , metabolic)
• Minearls
• Vitamins

• Method 1: Clip pieces of preferred food plants and measure protein content (measure of nitrogen)
• Method 2: Fecal nitrogen

• Minerals
• large amounts
• calcium, phosphorus, potassium, sodium, magnesium, chlorine, sulfur

• minerals
• smaller amounts
• iron, zinc, manganese, copper, selenium, iodine, molybdenum, fluoride, chromium

• Copper: twisted antlers, easy to break
• Selenium: muscle and bone abnormalities, porr juvenile survival

• Seasonal variation (summer/winter, or wet/dry) causes forage and quality availability to vary
• High quality (high energy, highly digestible) forage is available, store fat
• Animals reduce forage intake to conserve fat

• Surface to volume ratio also matters
• - Larger animals don't loose heat fast

• not just a response to predation
• an attempt to time reproduction for the most productive window of plant growth

• 1. Control of "top" predators to limit predation of game, endangered species, livestock, pets or humans
• - selective (removing problem individual)
• - non-selective ( aerial gunning / posion)
• - non-selective, harvest based (encourage hunting)
• 2. Control of mesopredators becasue top predators are absent
• 3. Control of exotic predators
• - non-selective

Density Dependence: transmission increases linearly with host population density (social contacts)

Independence (freq.) Dependence: rate at which hosts contact one another is independent of population density (sexual, vecot/host)

• Viruses, lungworms, scabies, internal parasites, fleas and ticks
• Ex.: Hells Canyon - Rocky Mountain BHS

• Deer (whitetail deer)
• Oral ulcers and abscesses
• labored breathing (acute onset of pneumonia)
• foaming or drooling at the mouth
• diarrhea
• weakness
• emaciation

• White-tailed deer, mule deer, pronghorn antelope
• loss of appetite
• weakness
• excessive salivation
• rapid pulse and respiration
• hemorrhage and lack of oxygen results in blue
• death 8-36 hours

• Deer\Young self-limiting
• Hair lose

• Hogs, bear, fox, wolf, cougar, seal, walrus
• blood test, cyst identification in muscle (tongue, masseter, diaphram)

• Deer (15 months) and Elk (12 months)
• Progressive weight loss and eventual death
• caused by prion transform proteins in brain to abnomral form
• transmission is animal to animal (oral ingestion: saliva, feces, urine, contaminated soil/surfaces)
• environmental contamination

• teeth grinding
• abnormal head posture
• aspiration pneumonia from excessive salivation
• clinical signs may occur with other illnesses and aren't diagnostic

• Regulating a population by means other than habitat management and public harvest
• Expensive
• Overabundant populations where harvest is not permitted or practical

• Capture and translocation
• Contraception
• Culling

• Logistically difficult (expensive and slow)
• Disease risk
• Liability risk for dangerous species
• Poor Survival

• More humane
• Cost effective
• Effective
• Long-lasting
• Doesn't drastically change behavior of target sp.
• Easliy deliverable (darts, jabstick, oral)
• Works: closed population (no emigration/immigration), tracked

• Removal and killing of surplus individuals by means other than public hunting not effective, feasible, acceptable
• Removed by professionals that can employ restricted models
• Results in fewer wounded animals

• Last resort
• Expensive
• Very careful tracking of pedigrees to prevent inbreeding
• Ex.: Red and Mexican Wolves

• Transporting individual to new or empty habitat
• Important strategy for creating, increasing, or maintaining populations of some species
• Adequate source population (disease-free, genetically diverse)
• Mortality in new habitat is high

Release animals at new site in a large protected pen to allow them to acclimate and recover from transport stress

• Meat/ hide/ antler/ horn for commercial use
• Raising animals for "canned" hunts
• Ranches that offer "canned" hunts
• Fee hunting
• Wildlife viewing

• Dispersal: kin avoidance
• Saturation dispersal: when population density become too high

measure of genetic distance between populations (0 to 1)