NRES 250 exam 1

1/23 History of Wildlife Management

management: manipulating the resource to achieve selected goals or end results

^^Era of Abundance^^

• ^^1400’s wildlife was enormously abundant^^
• European immigrants to North America ^^viewed wildlife as “commons”^^
• led to overexploitation
• passenger pigeon

^^Era of Overexploitation^^

• 300,000 deer in 1900
• the population of around 1,500,000 deer in Wisconsin alone

^^Era of Protection^^

• ^^immediate response to overexploitation^^
  • bag limits
  • regulations
  • artificial propagation
  • predator control
  • set aside reserves
• Bag limits
  • 1852 Maine hired salaried game wardens
  • 1873 Maine limited to 3 deer per year
  • 1887 Wisconsin limits bag on prairie chickens to 25/day
• Regulations
  • 1896 states own wildlife
  • 1900 Lacey Act prohibits the interstate shipment of illegally killed game
  • Among the first laws to protect wildlife
  • tied to commerce clauses of the US Constitution
  • 1913 weeks - clean act places migratory birds under federal control
• Artificial propagation
  • 1881 Oregon - judge Denny released ring-necked pheasants (spread coast to coast by 1900)
• Predator Control
  • no protection for all
  • wolf control
  • cattle ranching was popular in the late 1800s
  • states begin to pass anti-predator laws
  • 1914- predatory animal and rodent control established
• Set Aside Preserves
  • 1894 park protection act protects wildlife in national parks
  • 1903 1st national wildlife refuge - pelican island, Florida (51 more refuges established in 1904)

^^Era of Game Management^^

• ^^Wildlife management as a career^^
  • ^^habitat: a set of environmental conditions under which a species or community can exist^^
  • biotic or abiotic
  • science
  • regulations
• Habitat Manipulation
  • 1924 - quail management plan based on scientific studies by Herb Stoddard
• Scientific Guidance
  • 1933 - Aldo Leopold published Game Management
• Regulations - ^^1937 Pittman - Robertson Wildlife Restoration Act^^
  • ^^tax on hunting equipment^^
  • ^^money based on land area and hunting licenses sold^^
  • must go to state agencies for wildlife management
  • ^^fisheries have Dingell - Johnson Act^^ (does the same thing)

^^Era of Environmental Management^^

• habitat and ecology
• ^^biodiversity: the range of variation found among microorganisms, plants, fungi, and animals and the richness of species of living organisms^^
• identify and moderate threats
• laws and regulations
  • ^^endangered species act^^
  • other acts

1/25 Importance of Wildlife and Fisheries

^^Wildlife: wild by nature, naturally there, non-game which are not pursued for consumptive recreation, game species are harvested for recreation^^

^^Fishery: mostly aquatic lifestyle, game, and non-game definitions apply^^

Fisheries and wildlife involve: human users, organisms, and habitats

^^Methods for determining the economic value^^

• ^^direct expenditure method: money spent while participating in the activity^^
• ^^market value: price it would fetch in the market - determined by buyers and sellers in the market (lobster/crab at a restaurant)^^
• ^^willingness to pay: the amount an individual is willing to pay to acquire that good (truffles, goose liver, caviar)^^

^^Wildlife contributes $346 billion annually^^

Computer and electronics $374 billion

Oil and gas $409 billion

^^Consumptive Uses^^

• ^^food - a major use of fish and wildlife resources worldwide^^
• ^^recreation - hunting, fishing, and associated activities^^

^^Non- consumptive uses^^

• ^^bird watching^^

1/27 Land System Surveys

Why do we measure and describe land?

• establish legal ownership
• solve land disputes
• create political boundaries
• delineate natural resources management areas

Three land survey methods in the US

• ^^metes and bounds surveys^^
  • ^^used simple descriptions based known features (physiographic features and/or natural features) and measured distances^^
  • sounds simple, but can be confusing because many of the features no longer exist
• ^^us public land survey system (PLSS)^^
  • ^^a systematic naming convention^^
  • ^^location keyed to an initial point, formed by the intersection of 2 survey lines (Principle Meridian P.M. and the Base Line)^^
  • ^^Principle Meridian: a survey line running North/South through the initial point, used as the basis for any legal description because it uniquely defines a particular region of the country, using the county (or perish) and state is an accepted alt to the P.M.^^
  • ^^Base Line: survey line that runs East/West through the initial point^^
  • ^^Standard Parallels: survey lines running East/West and are located every 24 miles North and South of a particular initial point, run parallel to the baseline^^
  • ^^Guide Meridians: survey lines that run North and are located every 24 miles East and West of the P.M., curvature of the earth plays a role^^
  • ^^Township Lines: survey lines that run East/West and are used to position yourself North or South of the P.M. - baseline intersection, they are parallel to the baseline and are located every 6 miles North and South of each baseline^^
  • ^^Range Lines: survey lines that run North and are used to position yourself East or West of the P.M. - baseline intersection, they are fairly parallel to each P.M. or guide meridians, and are located every 6 miles east and west of the P.M.^^
  • ^^6 by 6 miles or 36 square miles are townships^^
  • ^^legal description: the ordering of these attributes is very important in a written legal description^^
  • ^^Section Lines: subdivide the 36 miles of Townships into 36 sections, each approximately 1 mile by 1 mile (dividing townships into sections) 1 square mile = 640 acres^^
  • ex S.23 T5N R4W Fourth P.M.
  • shortcut to get acres - multiply all the fractions by 640
• ^^french long lot^^
  • ^^1 chain = 66 feet^^
  • ^^80 chains = 1 mile (5,280/66=80)^^
  • ^^1 acre = 43,560 sq. ft. = 10 square chains^^

1/30 Attitudes and Values

Stakeholders

• naturalists
• anglers
• homeowners
• hunters
• tax-payers
• loggers

Resource managers must measure, evaluate and integrate

• biological elements
• socioeconomic elements
• cultural elements
• political elements

Components of public attitudes

• ^^affects = emotional component^^
• ^^beliefs = perceptions (cognitive component based on available information)^^
• intentions and actions based upon affects and beliefs

Attitudes toward wildlife - Kellert

• ^^naturalistic: wildlife and the out-of-doors^^
• ^^ecologistic: wildlife species and their habitats^^
• ^^humanistic: individual animals either wild or pet^^
• ^^moralistic: concerned with the ethical treatment of animals^^
• ^^scientific: interested in physical and biological attributes^^
• ^^aesthetic: values animals for artistic and symbolic characteristics^^
• ^^utilitarian: interested in the practical and material value of animals^^
• ^^dominionists: the desire to master and control animals^^
• ^^negativistic: avoid animals due to indifference, fear, dislike, or superstition^^
• ^^domination: human uses and benefits^^
• ^^mutualism: moral obligation^^

2/1 History of Forest Management

Historical Attitudes from Colonial Settlement to Today

• exploitation
• inexhaustible and a hindrance
• conservation/preservation
• sustainability

Pre European Settlement

• Native Americans managed forest
• openings created for villages
• clearings maintained with fire
• openings for ag use, maintained with fire
• land management and fire management today
• 1,038 million forested acres, contiguous 48 states
• about 750 million acres today

Colonial Settlement (1607 - 1783)

• settlers forest attitudes
  • a nuisance (inhibits settlement)
  • is inexhaustible
  • to be conquered
• Roles of forest - common property
  • key to settlement and economic growth
  • protective ordinances (regulation)
  • 1626, Plymouth Colony
  • 1681, Pennsylvania Colony
  • 1691, Broad Arrow Policy

Independence and the New Republic

• New government
  • weak central governement
  • no taxation
  • debt
• ^^Formation of the Public Domain (PD)^^
  • ^^the government used/sold PD^^
  • promote settlement
  • pay debt
• ^^Morrill Land Grant Act (1862)^^
  • ^^land grants colleges^^
  • ^^30,000 acres of land per member of congress^^
  • ag and mechanic arts
• ^^Homestead Act (1862)^^
  • ^^160 acres in the west^^
  • ^^small filing fee ($18)^^
  • ^^continuous residence 5 years^^
  • officially ended in 1976 Alaska 1986
• ^^Timber and Stone Act (1878)^^
  • ^^$2.50 per acre for land “not suitable for farming”^^

Developing Conerns

• westward expansion, the exploitation of resources, Civil war
• ^^1864 George Perkins Marsh authored Man and Nature^^
• George Catlin, Genry David Thoreau, Fredrick Law Olmsted, and John Muir warm of loss of wilderness and natural values
• 1886 Bernard Fernow (trained forester from Europe)
• ^^1891 Forest Reserve Act allowed the president to remove forest reserves from the Public Domain^^
• ^^Harrison set aside 13 million acres^^
• ^^Cleveland set aside 21 million^^
• ^^Theodore Roosevelt set aside 46.5 million acres and then increased to 167 million acres^^

New Philosophy Federal Lands Today

• 1897 Organic Act: provides for the management of forest reserves
  • ^^to improve and protect forests and provide for a continuous supply of water and timer^^
• ^^1898 Gifford Pinchot replaces Bernard Fernow^^
• ^^1898 Biltmore Forestry School opens (Carl Schenck)^^
• ^^1905^^
  • ^^transfer act: transfers management of forest reserves to the US department of ag division of^^ ^^forestry^^
  • us forest service replaces division of forestry
  • forest reserves become a national forest system
  • the greatest good, for the greatest number, in the long run
• ^^1928 McSweeny Mcnary Forest Research Act^^
  • ^^established inventorying and monitoring activities of the forest service^^

Expand Conflict/Social Change

• ^^1960 multiple use/sustained yield act: outdoor recreation, range, timber, watershed purpose, wildlife and fish purposes^^
• ^^1964 wilderness act^^
  • ^^focused on natural forces changing things not people, look at areas that are important, solitude^^
• ^^1969 national environmental policy act^^
  • ^^consider environmental impacts of significant management action, develop environmental impact statements^^
• ^^1973 endangered species act^^
  • ^^protection of endangered species, habitats, public and private lands, economic impacts^^
• ^^1974 resource planning act^^
• ^^1976 national forest management act^^
  • ^^brought biodiversity to the public, consider all uses of forest land^^
• ^^2003 healthy forests restoration act^^
  • ^^decreases wildlife threats and changed public review^^

Social Change

• Charles Cartwright - first African american forest service
• Eleanor Towns - first African american female forest service
• TIMOs (timber investment management organizations)
• REITs (real estate investment trusts)
• Carbon credits and new markets therein

2/3 History of Fish Management

Pre-European Settlers

• native American fisheries
  • spears, angling, fish traps, weirs, nets
  • subsistence fisheries
  • sustainable harvest
  • fish played an important cultural role

The Feudal System

• fish and wildlife owned by nobility
• granted rights for fishing and hunting
• illegal for the average person to fish or hunt
• carried over to north America

European Exploeres arrive in N.A.

• North America “New World”
• escape from feudalism
• Endless resources
• Salmon runs so large they inspired complaints
• Fish hauls large enough to need 4 houses to pull nets
• Europe experienced population growth, diminishing resources, the industrial revolution, the spread of Christianity
• the view that natural resources would fuel economic and religious fulfillment.

^^Tragedy of the Commons^^

• ^^depletion of a shared resource by individuals, acting independently and rationally according to each one’s self-interest despite their understanding that depleting the common resource is contrary to the group’s long-term best interests (everyone taking a little bit will deplete the resource)^^

N.A. Model of Wildlife Conservation and Public Trust Doctrine

• 1842 - Martin v. Waddell
• Common law foundation
• Seven focal points
  • ^^wildlife as public trust resource^^
  • ^^elimination of markets for game^^
  • ^^allocation of wildlife by law^^
  • ^^wildlife should only be killed for a legitimate purpose^^
  • ^^wildlife is considered an international resource^^
  • ^^science is the proper tool for the discharge of wildlife policy^^
  • ^^democracy of hunting^^

Fisheries in N.A. Who has authority

• management requires authority
  • aristocracy and nobility help property rights
  • disregard for N.A. tribes
• American Revolution
  • public trust doctrine
  • confusion
• In 1871
  • us commission on fish and fisheries
  • spencer barid
  • determine reasons for declining fish pops in N.E. and Great Lakes
  • fish culture

Early Fish Management

• first hatchery in the US in 1870
  • Seth green
  • Caledonia, NY
• American shad stocked
• railroad
  • widespread stocking
• management
  • limit harvest and access
  • stockfish

A critical turning point

• Dams
  • 1910 to 1970
  • FDR’s new deal
  • ccc
  • Most major NA rivers
  • little consideration of environmental impacts

^^Maximum Sustainable Yield (MSY)^^

• ^^early 1900’s^^
• ^^single objective = achieve the highest yield^^
• ^^the maximum biomass of a population that can theoretically be harvested without affecting future harvest^^
  • some regulations (size)
• did not guarantee the profitability of the fishery

Interjurisdictional Management

• Canada - US waters
  • great lakes
• Oceans
  • still and issue today
• States
  • great lakes
  • border waters
• Who has the authority
  • tragedy of the commons

Optimum Sustained Yield (OSY)

• late 1960s to early 1970s
• a management philosophy that considers ecological and socioeconomic factors

Magnunson- Stevens Act

• primary law governing marine fisheries
• preventing overfishing
• rebuild overfished stocks
• increase long-term economic and social benefits
• ensure a safe and sustainable supply of seafood
• signed into law in 1976

Sports Fish Management

• fishing as a “sport”
• brought from Europe
• although states had authority they had no money
• ^^Dingell-Johnson act (1950)^^
  • ^^federal excise tax^^
  • ^^federal aid in sport fish restoration^^
  • ^^similar to Pittman-Robertson act^^

Aboriginal Rights

• Native Americans
  • courts have upheld treaties (recently in 2000)
  • ceded territories

Modern Fisheries Management

• ^^harvest regulations^^
  • ^^size, creel, seasons, etc^^
  • ^^licenses^^
  • ^^stocking^^
  • ^^ecological management^^
  • predator-prey
  • fish communities
  • energetic analyses
  • genetics

2/6

Sampling Forest Resources

Reasons for Frest Sampling

• general info
• management
• timber valuation
• other valuation

Common Tree Meausures

• ^^DBH^^
  • ^^diameter at breast height^^
  • ^^outside bark diameter measured 4.5 feet above ground^^
  • measured with DBH tape, calipers, or perhaps a Biltmore Stick
  • “the name of the class is the center of the class”
  • 1-inch wide classes. go down to 0.6 and up to the 0.5
  • 2-inch wide classes. go down to 0.1 and up to the 0
  • ^^size classes - seedling less than 4.5 feet tall^^
  • ^^sapling 0” < DBH < 5.5”)^^
  • ^^size classes - pole or pulpwood and saw timber^^
• ^^Basal Area (typically expressed per acre) 80 - 180 avg^^
  • ^^outside bark cross-sectional area (in sq ft) measured 4.5 feet above ground^^
  • most often expressed on a per acre basis
• Height
• Age
• Volume or Weight (typically expressed per acre)

^^cull: a nonmerchantable living tree^^

^^snag: a standing dead tree^^

Height

• total tree height - distance from the ground to the tree top if on a slop measure from the uphill side
• clinometer used - height top number minus the bottom number
• merchantable height

logs and sticks

• ^^sawlog: 16 feet long, can count in half logs after the first full log^^
• ^^pulp stick: 8 feet long, whole sticks only^^
• alternative forms of measuring height

Age

• typically measured with an increment borer

Sampling methods

• ^^fixed radius plot sampling^^
  • ^^measuring circular plots that are typically some fraction of an acre^^
  • ^^measure it if it is on the plot^^
• ^^variable radius plot sampling (point sampling)^^
  • ^^use a prism to determine which trees to measure (10 factor prism most common)^^

^^Sampling for Management^^

• ^^trees per acre^^
• ^^basal area per acre^^
• both are measures of stocking (density)
• can be obtained with plot or point sampling with a little effort

^^Sampling for Timber Valuation^^

• ^^volume per acre^^
• ^^saw timber: board feet per acre^^
• ^^pulpwood: cords per acre^^
• ^^can be obtained with plot or point sampling^^
• shortcut formulas exist when using point sampling

^^Board Feet^^

• ^^the most common measure of sawtimber volume^^
• ^^1 board foot is equivalent to a plank^^
• ^^typically expressed in board feet per acre or MBF per acre^^
• ^^1 MBF = 1000 BF^^

^^Cords^^

• ^^the most common measure of pulpwood volume^^
• ^^1 cord = 128 cubic feet of stacked pulpwood^^
• ^^128 cu ft includes wood content bark and space^^
• ^^1 cord contains less than 128 of wood^^

2/8

Sampling Fish and Wildlife Population

Sample: a subset or portion of the total number of organisms in a population

Representative Sample

• goal - sample = population
  • samples need to be representative
• issues
  • some organisms more vulnerable to capture than others

Selectivity and Bias

• different gears have different selectivity which results in different bias
  • bias: difference or distance between and estimate value and the true parameter
• mean weight of black crappies
  • sample estimate = 100 grams
  • actual value = 125 grams
• this means our gear selects for smaller black crappies

Other sampling considerations

• many sample devices require a permit
  • gill nets, electrofishing, rocket nets
• some techniques are lethal
• sampling stresses organisms
• ^^sampling can alter behavior^^
  • ^^trap happy, trap shy^^

^^Sampling Gears^^

• ^^active vs passive (require the animal to come and engage with the gear)^^

2/10 ^^Uses of Marked Animals^^

• ^^movements and migrations^^
• ^^habitat use^^
• ^^behavior patterns^^
• ^^age and growth^^
• ^^stocking success^^
• ^^abundance and mortality^^

Estimating Population Size

• ^^capture - mark - recapture^^
  • conduct a sampling trip
  • mark all individuals (M) in the first sample
  • conduct a second sampling trip
  • must be a random sample
  • examine all individuals (C) looking for marked (R)
  • estimate the number of N in the population

2/13

Animal Behavior and Management

^^Ethology: the study of animal behaviors under natural conditions^^

Why do animals behave as they do?

• proximate causes
  • neurological and physiological mechanisms
  • ^^circannual rhythm: pattern of behavior that occurs predictably over the course of year^^
  • ^^circadian rhythm: pattern of behavior that occurs predictably over the course of a day^^
• ultimate causes
  • survival or reproductive benefit

Types of behavior

• ^^innate^^ ^^behaviors^^
  • ^^genetically programmed^^
  • ^^taxis or reflex^^
  • ^^taxis: oriented movement toward or away from a stimulus^^
  • ^^not easily modified^^
• ^^learned behaviors^^
  • ^^trial and error^^
  • ^^easily modified^^
• ^^imprinting: learning which occurs during a critical period of time^^

Early Life

• ^^precocial - alert and well developed^^
• ^^altricial - require more parental care^^

Habitat Selection

• has a genetic component, but it can be modified by learning

Social Behavior

• hierarchies: status systems in animals societies
  • fewer fights
  • less tension
  • lower energy loss

Social Organization

• behavior and genetics
  • altruism - caregiving is costly
  • kin selections - benefits relatives (justify altruism)
  • benefits of flocking (living in a group)
  • detects predators
  • confuse predators
  • feeding and hunting advantages
  • synchronize breeding
  • facilitate movement

Partitioning Resources

• ^^home range - an area where an individual normally travels in their daily duties^^
• territories - defended
  • ^^mating - lek: breeding site-dance^^
  • nesting
  • feeding
  • loafing

Reproduction

• leave as many offspring as possible
• mating systems
  • ^^monogamous - strong pair bonds^^
  • ^^polygamous - several mates^^

Communication

• ^^ritualized behavior and displays, often involving special anatomical features^^
• ^^postures^^
• ^^auditory^^
• ^^visual^^
• ^^chemical - pheromones^^

Management Implications

• reproduction - manage species
  • sex ratios for breeding
  • adjust harvest to match breeding
• pest control
• translocation of problem animals
• pheromone traps
• taxis - mosquitoes
• censusing wildlife
  • breeding - lek behavior
  • auditory - howling surveys
  • migration corridors
• research - capture
  • pecking order
  • territoriality
• learned behavior - captive breeding
• imprinting - captive breeding

2/17 Determining age, growth, and sex in fish and wildlife

^^Fish age = calcified structures^^

^^How do annuli form?^^

• ^^deposition of daily rings or circuli^^
• ^^circadian rhythm (circular, 24 hours)^^
• ^^temperate region - growth slows in winter^^
• ^^slower growth + daily rings closer together^^
  • ^^winter^^
• ^^faster growth = daily rings farther apart^^
  • ^^summer^^
• ^^different in marine fish, tropics, and other cases^^
• ^^annuli only form during the winter^^

^^Scales^^

• very common
  • easy removal, nonlethal
• poor accuracy for older fish
• annuli “crowd” as growth slows

^^Otoliths^^

• ^^inner ear bones^^
• lethal
• higher accuracy than scales
• can be sectioned

^^Spines^^

• nonlethal
• more accurate than scales
• must be cut or sectioned
• ^^not as good as otoliths for older (>10 years) fish^^

Age of Lake Trout in Lake Superior

• scales indicated trout were ages 5 to 13
• otoliths - age 8 to 28
• disagreements of 2 to 20 years
• scales age resulted in biased estimates of growth
• trout had a more diverse age structure and lower mortality than previously thought

^^Cementum annuli - mammals^^

• ^^section teeth^^
• ^^dark annuli form during winter^^
• ^^light areas form during spring/summer^^

when we can estimate age

• terminology
• ^^age group of age class = all individuals of designated age^^
• ^^year class or cohort = all individuals born in a specific year^^

^^other age estimation methods'^^

• ^^anatomical measurements^^
• ^^gonad development^^
• ^^morphology^^
• ^^coloration^^

Age ratio in birds

• adult: juvenile rations
• recruitment
• survival
• cost-benefit

Estimation Growth

• typically accompanied age estimation
• define growth per unit of time
• light for fish
• weight for wildlife
• ^^need a measure of size and a measure of time (age)^^

Measuring growth

• collect a sample
• weigh and measure
• estimate ages
• calculate the mean length/weight at each ages

^^biochronology^^

• ^^growth history^^
• assume the growth of fish is related to the growth of selected aging structure
• proportional i some cases
• ^^distance between annuli = annual growth^^
• useful when sampling of a population is sporadic

using growth information

• population indicator
• what does poor growth indicate
• fishers - length limits

determining sex - external

• nonlethal
• sexual dimorphism
• sexual dichromatism
• urogenital morphology
• gamete extrusion
• ultrasound

2/20 Forest Regions

• ^^forest region - biome^^
• factors of biomes
  • climate and soils
  • geography
  • ecophysiology factors
  • water, nutrients, solar radiation, temp
  • anthropogenic (human)
• ^^physiognomy^^
  • ^^similar climates - similar vegetation appearance^^

Forest Regions of North America

• ^^Northern Coniferous^^

  • climate - very cold, short growing seasons
  • soils - slow to develop, nutrient-poor
  • the southern portion is part of the boreal forest
  • species - spruce, fir, pine
  • some birch, aspen, and willow appear in the southern part
  • lichens and sphagnum moss are common

• ^^Northern Hardwoods Forest^^

  • climate - cold in winter, moderate growing season
  • soils - still relatively new, increasing fertility the father south on goes in the region
  • species - maple, hickory, beech, ash, walnut, yellow poplar, oak, basswood
  • fairly well-developed understory
  • the land is sometimes planted in red pin or scotch pine plantations (CCC work)

• ^^Pacific Coast Forest^^

  • climate - temperate proximity to the ocean, plenty of moisture
  • soils - moderately deep ( developed) with high organic content near the surface
  • species - douglas fir, sitka, spruce, western hemlock, redwood on the best sites
  • much coniferous material - fire concerns

• ^^Rocky Mountain Forest^^

  • climate - cold but moist, relatively short growing season
  • soils - varied in development and fertility
  • species - ponderosa pine, lodgepole pine
  • pinyon-juniper forests, sagebrush present (fire concerns)

• ^^Central Broad-Level Forest^^

  • climate - medium, somewhat lengthier growing season
  • soils - tend to be drought but some have good moisture-holding capacity
  • “upland hardwood forest”
  • species - post oak, blackjack oak, bur oak, chestnut oak, white oak, black oak, northern red oak

• ^^Oak-Pine Forest^^

  • climate - mild winters, fairly hot summer, late summer droughts
  • soils - drought, fairly nutrient-poor, coarse-textured soils
  • species - shortleaf pine mixed with the oak species including southern red oak

• ^^Southern Pine Forests^^

  • climate - same as previous
  • soils - sandy
  • southern part of the Oak Pine region
  • loblolly pine and shortleaf pine in the northern portion
  • longleaf pine and slash pine in the southern portion
  • the yellow pines

• ^^Bottomland Hardwood Forest^^

  • climate - same as previous, frequent flooding
  • soils - silty, very fertile
  • species - cottonwood, willow oak, water oak, cherry bark oak, overcup oak

• ^^Tropical Forests^^

  • climate - hot and humid
  • soils - deep organic layer

• ^^Wisconsin - 36 million acres^^

• ^^forested - 16 million acres^^

• ^^largest cover type - 2.8 million acres of aspen^^

2/22 Dynamics of Fish and Wildlife Populations

population dynamics: studying changes in population size or biomass (weight)

R, G, M

• ^^recruitment: natality, the addition of new organisms to a population^^
• ^^growth: addition of biomass to an individual or population^^
• ^^mortality: deaths in a population^^
• these dynamic rates interact to shape or structure a population

Recruitment

• number of organisms present or surviving to a specified point in time
• sometimes a rate or recruitment
• wildlife = births or birth rates often used in describing recruitment
• fish = often some measure of relative abundance
• density-dependent (biotic)
  • adults/spawners dictate number of recruits in a predictable manner
  • biotic>abiotic
  • lots of adult ducks = lots of baby ducks
  • low numbers of spawning Walleye = low recruitment
• density-independent (abiotic)
  • environmental conditions strongly influence recruitment
  • drought or heavy precipitation = poor hatching success in birds
  • thermal regime in spring can regulate fish recruitment

Growth

• accumulation of biomass
• individuals increase in body size with age
• increases towards some maximum level
  • early growth is faster than later growth
  • maturation causes growth to slow down
• growth can also be density-dependent
  • high density often leads to slow growth
  • low density often leads to fast growth

Fish vs. Wildlife

• fish are cold-blooded
  • grow at an indeterminate rate
  • temp is the same as the water
  • growth depends on food supply and temp
• mammals are warm-blooded
  • grow at a determinate rate
  • temp is self-regulated
  • growth depends on food less on temp

Measuring Growth

• collect a sample
  • weigh and measure
  • remove structures for aging
  • calculate mean length/weight at age
• mark-recapture
• size and time

Mortality

• natural causes (disease, starvation, etc.)
• harvest mortality
• total mortality = natural and harvest
• density-dependent (competition, predation)
• density-independent (environmental)

Estimating Mortality

• catch curve or life table
• collect a sample of organisms
  • estimate ages
  • look at the rate of decline in numbers over time
• mark-recapture
• make animals at time 1
• visible tags
  • people report tags from harvested animals
  • biologists check harvested animals for marks
• how many tagged animals are left at time 2
• biotelemetry (tracking)
• wait until the animal dies, find the tag, and determine the cause of death
• examples - trout tag near otter den = predation, turkey carcass on road = vehicle collision

Additive = total mortality increases with increases in harvest mortality

Population Growth

• exponential increase at low abundance
  • reproductive potential; = internal
  • the intrinsic rate of increase (r) is related to the innate reproductive rate
• increase more slowly at high abundance
  • environmental more slo