Chapter 13:Chapter 13:Wildlife, Fisheries and Wildlife, Fisheries and Endangered SpeciesEndangered Species

OverviewOverview

Traditional Single-Species Wildlife ManagementTraditional Single-Species Wildlife Management Improved Approaches to Wildlife ManagementImproved Approaches to Wildlife Management FisheriesFisheries Endangered Species: Current StatusEndangered Species: Current Status How a Species Becomes Endangered and ExtinctHow a Species Becomes Endangered and Extinct The Good News: We Have Improved Some SpeciesThe Good News: We Have Improved Some Species Can A Species Be Too Abundant?Can A Species Be Too Abundant? How People Cause Extinction and Affect Biological DiversityHow People Cause Extinction and Affect Biological Diversity Ecological Islands and BiodiversityEcological Islands and Biodiversity Using Spatial Relationships to Conserve Endangered SpeciesUsing Spatial Relationships to Conserve Endangered Species

Single-Species Wildlife Single-Species Wildlife ManagementManagement

Each species viewed as a single Each species viewed as a single population in isolationpopulation in isolation

Assumptions:Assumptions: Population only represented by a single Population only represented by a single

number- total sizenumber- total size Population would grow to its carrying capacityPopulation would grow to its carrying capacity Environment, except for human-induced Environment, except for human-induced

changes, is constantchanges, is constant

Single-Species Wildlife Single-Species Wildlife ManagementManagement This perception illustrated by the S-shaped This perception illustrated by the S-shaped

logistic growth equationlogistic growth equation Two management goals resulted:Two management goals resulted:

For a species we intend to harvest: maximum For a species we intend to harvest: maximum sustainable yield (MSY)sustainable yield (MSY)

For a species we intend to conserve: keep For a species we intend to conserve: keep population at its carrying capacitypopulation at its carrying capacity

Single-Species Wildlife Single-Species Wildlife ManagementManagement This approach failed because none of the This approach failed because none of the

assumptions were accurateassumptions were accurate Population cannot be represented only by a single Population cannot be represented only by a single

numbernumber Population does not remain at a fixed carrying Population does not remain at a fixed carrying

capacitycapacity The environment is not constantThe environment is not constant

Single-Species Wildlife Single-Species Wildlife ManagementManagement Necessary to include an ecosystem and Necessary to include an ecosystem and

landscape context for conservation and landscape context for conservation and managementmanagement

New goals:New goals: For a species to be harvested: sustain a For a species to be harvested: sustain a

harvestable population in a sustainable harvestable population in a sustainable ecosystemecosystem

For a species that is threatened or endangered: For a species that is threatened or endangered: minimum viable populationminimum viable population

Logistic Growth CurveLogistic Growth Curve

Include the following ideas:Include the following ideas: A population that is small in relation to its A population that is small in relation to its

resources grows at a nearly exponential rateresources grows at a nearly exponential rate Competition among individuals in the population Competition among individuals in the population

slows the growth rateslows the growth rate The greater the # of individuals, the greater the The greater the # of individuals, the greater the

competition and the slower the rate of growthcompetition and the slower the rate of growth Eventually, a point is reached, called the “logistic Eventually, a point is reached, called the “logistic

carrying capacity”carrying capacity”

Logistic Growth CurveLogistic Growth Curve

Using this growth curve:Using this growth curve: The number of births in a unit time equals the The number of births in a unit time equals the

number of deaths, and the population is constant.number of deaths, and the population is constant. A population can be described simply by its total A population can be described simply by its total

numbernumber Therefore, all individuals are equalTherefore, all individuals are equal The environment can be assumed to be constantThe environment can be assumed to be constant

Carrying CapacityCarrying Capacity

Three definitionsThree definitions1.1. Logistical carrying capacity-Logistical carrying capacity-

Number of individuals is just sufficient for the Number of individuals is just sufficient for the available resourcesavailable resources

2.2. An abundance at which a population can An abundance at which a population can sustain itself without any detrimental effects that sustain itself without any detrimental effects that would decrease the ability of that species to would decrease the ability of that species to maintain that abundancemaintain that abundance

3.3. Optimum sustainable population-Optimum sustainable population- Maximum population that can be sustained Maximum population that can be sustained

indefinitelyindefinitely

Logistic Growth CurveLogistic Growth Curve

Maximum sustainable yield (MSY)Maximum sustainable yield (MSY) Exactly one-half of the carrying capacityExactly one-half of the carrying capacity Other estimating MSY will lead to overharvestingOther estimating MSY will lead to overharvesting

Improved Approaches to Wildlife Improved Approaches to Wildlife ManagementManagement

Four principles of wildlife Four principles of wildlife conservationconservation

1.1. A safety factor in terms of A safety factor in terms of population size, to allow population size, to allow for limitations of for limitations of knowledge and the knowledge and the imperfections of imperfections of proceduresprocedures

2.2. Concern w/ the entire Concern w/ the entire community of organisms community of organisms and all the renewable and all the renewable resourcesresources

3.3. Maintenance of the Maintenance of the ecosystem of which ecosystem of which the wildlife are a the wildlife are a partpart

4.4. Continual Continual monitoring, monitoring, analysis, and analysis, and assessmentassessment

Improved Approaches to Wildlife Improved Approaches to Wildlife ManagementManagement

Time Series and Historical Range Time Series and Historical Range of Variationof Variation

Known range of abundance Known range of abundance of a population of species of a population of species over some past time over some past time intervalinterval

Ex: American whooping Ex: American whooping cranecrane

Time seriesTime series Set of estimates over a number of Set of estimates over a number of yearsyears

Historical range variationHistorical range variation

Age Structure as Useful Age Structure as Useful InformationInformation

Age StructureAge Structure Additional key to successful wildlife managementAdditional key to successful wildlife management

Ex: Salmon from the Columbia River, WAEx: Salmon from the Columbia River, WA Shift in catch towards younger agesShift in catch towards younger ages Overall decline in catchOverall decline in catch Suggests that the fish were being exploited to a point at Suggests that the fish were being exploited to a point at

which they were not reaching older ageswhich they were not reaching older ages Early sign of overexploitationEarly sign of overexploitation

Harvests as an Estimate of Harvests as an Estimate of NumbersNumbers Number harvested- method of estimating Number harvested- method of estimating

animal populations animal populations Previous animal abundance can be estimated Previous animal abundance can be estimated

by by ccatch per unit effortatch per unit effort Assumes same effort by all hunters/fisherman Assumes same effort by all hunters/fisherman

per unit timeper unit time If total time spent hunting and catch per unit If total time spent hunting and catch per unit

effort is known, population can be estimatedeffort is known, population can be estimated Ex: Bowhead whaleEx: Bowhead whale

FisheriesFisheries

Fish are an important food sourceFish are an important food source 16% of the world’s protein16% of the world’s protein 6.6% of food in North America6.6% of food in North America

Continental shelves Continental shelves Only 10% of ocean areaOnly 10% of ocean area Provide 90% of fish harvestProvide 90% of fish harvest Areas of high algae production to support food Areas of high algae production to support food

chain chain Upwelling Upwelling

FisheriesFisheries World fish harvest has increased greatly since the World fish harvest has increased greatly since the

middle of the 20middle of the 20thth century century Increased number of boatsIncreased number of boats Improved in technologyImproved in technology Increase in aquaculture productionIncrease in aquaculture production

The Decline of Fish The Decline of Fish PopulationsPopulations Evidence that fish populations were declining Evidence that fish populations were declining

came from the catch per unit effortcame from the catch per unit effort Suggests fishing depletes fish quicklySuggests fishing depletes fish quickly About 80% decline in 15 yearsAbout 80% decline in 15 years

Commercial fisheries are mining a resource Commercial fisheries are mining a resource not sustaining itnot sustaining it

The Decline of Fish The Decline of Fish PopulationsPopulations Ex: Chesapeake BayEx: Chesapeake Bay

Famous for oysters and crabsFamous for oysters and crabs Breeding and spawning ground for many Breeding and spawning ground for many

commercially valuable speciescommercially valuable species Food webs very complexFood webs very complex Also influenced by runoff, introductions, Also influenced by runoff, introductions,

development, alteration in salinitydevelopment, alteration in salinity

The Decline of Fish The Decline of Fish PopulationsPopulations

Crisis has arisen for one Crisis has arisen for one of the living resources of the living resources most subjected to most subjected to science-based science-based managementmanagement Management based on Management based on

logistic growth curvelogistic growth curve Fisheries subjected to the Fisheries subjected to the

“tragedy of the commons”“tragedy of the commons”

The Decline of Fish The Decline of Fish PopulationsPopulations Fishing gear can be destructive to habitatFishing gear can be destructive to habitat

Ground-trawling equipment destroys the ocean Ground-trawling equipment destroys the ocean floorfloor

Long-line fishing kills sea turtles and other non-Long-line fishing kills sea turtles and other non-target surface animalstarget surface animals

Large tuna nets have killed dolphinsLarge tuna nets have killed dolphins

Can Fishing Ever be Can Fishing Ever be Sustainable?Sustainable? Few wild biological resources can sustain a Few wild biological resources can sustain a

harvest at a level that meets even low harvest at a level that meets even low requirements for a growing businessrequirements for a growing business

We can turn to farming fish (aquaculture)We can turn to farming fish (aquaculture) Important food source in China, growing Important food source in China, growing

worldwideworldwide Can create environmental problemsCan create environmental problems

Ex: Atlantic salmon fisheries cause water pollution and Ex: Atlantic salmon fisheries cause water pollution and loss of genetic diversityloss of genetic diversity

Endangered Species: Current Endangered Species: Current StatusStatus Number of species listed as threatened or Number of species listed as threatened or

endangered increasingendangered increasing IUCN maintains a list known as the Red ListIUCN maintains a list known as the Red List

20% of all know mammals at risk20% of all know mammals at risk 31% of amphibians31% of amphibians 3% of fish3% of fish 12.5% of plants recently extinct or endangered12.5% of plants recently extinct or endangered

Endangered Species: Current Endangered Species: Current StatusStatus The term endangered species as defined by the The term endangered species as defined by the

Endangered Species ActEndangered Species Act ““Any species which is in danger of extinction throughout all Any species which is in danger of extinction throughout all

or a significant portion of its range…”or a significant portion of its range…” With the exception of insect pestsWith the exception of insect pests

The term threatened speciesThe term threatened species ““Means any species which is likely to become an Means any species which is likely to become an

endangered species w/in the foreseeable future throughout endangered species w/in the foreseeable future throughout all or a significant portion of its range.”all or a significant portion of its range.”

How a Species Becomes How a Species Becomes Endangered and ExtinctEndangered and Extinct Local extinctionLocal extinction

Occurs when a species disappears from a part of Occurs when a species disappears from a part of its range but persist elsewhereits range but persist elsewhere

Global extinctionGlobal extinction Means a species can no longer be found Means a species can no longer be found

anywhereanywhere

How a Species Becomes How a Species Becomes Endangered and ExtinctEndangered and Extinct Rate of extinctions has varied over geologic Rate of extinctions has varied over geologic

timetime From 580 million years ago until 1800s, ~1 From 580 million years ago until 1800s, ~1

species per year went extinctspecies per year went extinct Rate of evolution of new species = or > the rate of Rate of evolution of new species = or > the rate of

extinctionextinction Average longevity of a species 10 million yearsAverage longevity of a species 10 million years

Other periods of “punctuated extinctions”Other periods of “punctuated extinctions”

Causes of ExtinctionCauses of Extinction

Population RiskPopulation Risk Problem for species in low abundanceProblem for species in low abundance

Environmental RiskEnvironmental Risk Variation in physical or biological environmentVariation in physical or biological environment

Natural CatastropheNatural Catastrophe Sudden change in the environmentSudden change in the environment

Genetic RiskGenetic Risk Reduction in genetic variationReduction in genetic variation

The Good News…The Good News…

Thanks to people, many previously Thanks to people, many previously endangered species have recoveredendangered species have recovered Aleutian gooseAleutian goose Elephant sealElephant seal Sea otterSea otter Blue whaleBlue whale Bald eagleBald eagle OspreyOsprey

Can a Species Be Too Can a Species Be Too Abundant?Abundant? Protected animals can become locally Protected animals can become locally

overabundantoverabundant Sea lions in San Francisco HarborsSea lions in San Francisco Harbors

Sun themselves on boat Sun themselves on boat Pollute water with fecesPollute water with feces

Mountain lions in CAMountain lions in CA People living in lion hunting groundsPeople living in lion hunting grounds More frequent human attacksMore frequent human attacks

How People Cause Extinctions and How People Cause Extinctions and Affect Biological DiversityAffect Biological Diversity

People cause ExtinctionsPeople cause Extinctions Hunting or harvestingHunting or harvesting Disrupting or eliminating habitatsDisrupting or eliminating habitats Introducing exotic speciesIntroducing exotic species Creating pollutionCreating pollution

75% of Extinctions since the 1600s have 75% of Extinctions since the 1600s have been caused by humansbeen caused by humans

Ecological Islands and Endangered Ecological Islands and Endangered SpeciesSpecies Ecological IslandEcological Island

Areas that are biologically isolatedAreas that are biologically isolated

Examples: Examples: islands, Small islands, Small city parks (ex: city parks (ex: Central Park in Central Park in NYC) and large NYC) and large nature nature preserves are preserves are both isolatedboth isolated

Ecological Islands and Endangered Ecological Islands and Endangered SpeciesSpecies How large must an ecological island be to How large must an ecological island be to

ensure survival of a species?ensure survival of a species? Depends on species requirementsDepends on species requirements

Using Spatial Relationships to Using Spatial Relationships to Conserve Endangered SpeciesConserve Endangered Species

Red-cockaded woodpeckerRed-cockaded woodpecker An endangered speciesAn endangered species Nests in old dead or dying pinesNests in old dead or dying pines Feeds on pine bark beetle which are a pest to the treeFeeds on pine bark beetle which are a pest to the tree

Using Spatial Relationships to Using Spatial Relationships to Conserve Endangered SpeciesConserve Endangered Species A new approach to conservationA new approach to conservation

Overlay a map of one’s habitat requirements over Overlay a map of one’s habitat requirements over a map of the other’sa map of the other’s

Co-occurrence can be compared and allow Co-occurrence can be compared and allow maintenance of all three speciemaintenance of all three specie