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Sustaining Biodiversity: The Ecosystem Approach


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Title: Sustaining Biodiversity: The Ecosystem Approach

Sustaining Biodiversity The Ecosystem Approach
  • Chapter 9

What is the most threatened ecosystem?Why?
Three big ideas
  • The economic value of ecological services are far
    greater than the value of raw materials obtained
    from those systems.
  • We can sustain terrestrial biodiversity by
    protecting severely threatened areas, protecting
    remaining undisturbed areas, restoring damaged
    ecosystems, and sharing with other species
  • We can sustain aquatic biodiversity by
    establishing protected sanctuaries, managing
    coastal development, reducing water pollution,
    and preventing overfishing.

What are the major threats to forest ecosystems?
  • Section 9-1

Forests vary in their age, make-up, and origins
  • Natural and planted forests occupy about 30 of
    the Earths tree-friendly land surface.
  • Two major types based on their age and structure
  • Old growth forest
  • Second-growth forest

Forests vary in their age, make-up, and origins
  • A tree plantation (tree farm, commercial forest),
    is usually made up of how many species?What ages
    of trees? How diverse? Good or Bad?
  • Forests provide important economic and ecological
  • Help with global warming HOW?

The short rotation cycle of cutting and regrowth
of a monoculture tree plantation
Forests provide many important economic and
ecological services
How do they contribute to economies?

What services do they provide?
Unsustainable logging is a major threat to forest
  • Methods of harvesting trees
  • Selective cutting.
  • Clear-cut.
  • Strip cutting.

Unsustainable logging is a major threat to forest
  • The first step in harvesting trees is to build
    roads for access and timber removal, but they can
    cause the following problems
  • Increased erosion and sediment runoff into
  • Habitat fragmentation.
  • Loss of biodiversity.
  • Forest exposure to invasion by nonnative pests,
    diseases, and wildlife species.

Three major tree harvesting methods
Aerial view showing clear-cut logging, Washington
  • How about forest fires are they good or bad?!?!

Fire can threaten or benefit forest ecosystems
  • Surface fires usually burn only undergrowth and
    leaf litter on the forest floor.
  • Kills seedlings and small trees but spares most
    mature trees and allows most wild animals to
  • Burns away flammable ground material and may help
    to prevent more destructive fires.
  • Frees valuable mineral nutrients tied up in
    slowly decomposing litter and undergrowth.

Fire can threaten or benefit forest ecosystems
  • Releases seeds from the cones of lodgepole pines.
  • Stimulates the germination of certain tree seeds
    (e.g. giant sequoia and jack pine).
  • Helps to control tree diseases and insects.
  • Crown fires are extremely hot fires that leap
    from treetops, burning whole trees.
  • Can destroy most vegetation, kill wildlife,
    increase soil erosion, and burn or damage human
    structures in their paths.

Surface fires and crown fires
Almost half of the worlds forests have been cut
  • Deforestation is the temporary or permanent
    removal of large expanses of forest for
    agriculture, settlements, or other uses.
  • Human activities have reduced the earths
    original forest cover by about 46, with most of
    this loss occurring in the last 60 years.
  • If current deforestation rates continue, about
    40 of the worlds remaining intact forests will
    have been logged or converted to other uses
    within two decades, if not sooner.

Almost half of the worlds forests have been cut
  • Clearing large areas of forests, especially
    old-growth forests, has important short-term
    economic benefits, but it also has a number of
    harmful environmental effects.
  • The net total forest cover in several countries
    changed very little or even increased between
    2000 and 2007. Some due to natural reforestation
    by secondary ecological succession on cleared
    forest areas and abandoned croplands, or the
    spread of tree plantations.
  • Concern about the growing amount of land occupied
    by commercial tree plantations, because
    replacement of old-growth forests by these
    biologically simplified tree farms represents a
    loss of biodiversity, and possibly of stability,
    in some forest ecosystems.

Harmful effects of deforestation
Forest cover in the U.S.
CASE STUDY Many Cleared Forests in the United
States Have Grown Back
  • Forests that cover about 30 of the U.S. land
    area provide habitats for more than 80 of the
    countrys wildlife species and supply about
    two-thirds of the nations surface water.
  • Today, forests in the U.S. cover more area than
    they did in 1920, primarily due to secondary
  • Every year, more wood is grown in the U.S. than
    is cut and the total area planted with trees
  • Protected forests make up about 40.
  • Since the mid-1960s, an increasing area of the
    nations remaining old-growth and fairly diverse
    second-growth forests has been cut down and
    replaced with biologically simplified tree

Tropical forests are disappearing rapidly
  • Tropical forests cover about 6 of the earths
    land area.
  • At least half of the worlds known species of
    terrestrial plants and animals live in tropical
  • Brazil has more than 30 of the worlds remaining
    tropical rain forest in its vast Amazon basin.
  • At the current rate of global deforestation, 50
    of the worlds remaining old-growth tropical
    forests will be gone or severely degraded by the
    end of this century.

Major underlying and direct causes of the
destruction and degradation of tropical forests
How should we manage and sustain forests?
  • Section 9-2

We can manage forests more sustainably
  • Certification of sustainably grown timber and of
    sustainably produced forest products can help
  • Removing government subsidies and tax breaks that
    encourage deforestation would also help.

Ways to grow and harvest trees more sustainably
Ways to protect tropical forests and use them
more sustainably
How should we manage and sustain grasslands?
  • Section 9-3

Left of fence overgrazed landRight lightly
grazed land
Restoration via secondary ecological succession
How should we manage and sustain parks and nature
  • Section 9-4

CASE STUDY Stresses on U.S. Public Parks
  • The U.S. national park system, established in
    1912, includes 58 major national parks, along
    with 335 monuments and historic sites. States,
    counties, and cities also operate public parks.
  • What are the problems?!?

Costa Ricas eight megareserves
CASE STUDY Costa RicaA Global Conservation
  • Tropical forests once completely covered Costa
    Rica, but between 1963 and 1983 much of the
    countrys forests were cleared to graze cattle.
  • Costa Rica is a superpower of biodiversity, with
    an estimated 500,000 plant and animal species.
  • Costa Rica now has a system of nature reserves
    and national parks that, by 2010, included about
    a quarter of its land.
  • Costa Rica now devotes a larger proportion of its
    land to biodiversity conservation than does any
    other country

CASE STUDY Costa RicaA Global Conservation
  • The countrys largest source of income is its
    1-billion-a-year tourism industry, almost
    two-thirds of which involves ecotourism.
  • To reduce deforestation, the government has cut
    subsidies for converting forest to rangeland.
  • The government pays landowners to maintain or
    restore tree cover.
  • Between 2007 and 2008, the government planted
    nearly 14 million trees.
  • Went from having one of the worlds highest
    deforestation rates to having one of the lowest.

CASE STUDY Controversy over Wilderness
Protection in the United States
  • Conservationists have been trying to save wild
    areas from development since 1900.
  • The Wilderness Act (1964) allowed the government
    to protect undeveloped tracts of public land from
    development as part of the National Wilderness
    Preservation System.
  • Only about 2 of the land area of the lower 48
    states is protected, most of it in the West.

What is the ecosystem approach to sustaining
  • Section 9-5

Biodiversity hotspots
Here are four ways to protect ecosystems
  • Most biologists and wildlife conservationists
    believe that the best way to keep from hastening
    the extinction of wild species through human
    activities is the ecosystems approach, which
    protects threatened habitats and ecosystem

Here are four ways to protect ecosystems
  • Four-point plan of the ecosystems approach
  • Map the worlds terrestrial and aquatic
    ecosystems and create an inventory of the species
    contained in each of them and the ecosystem
    services they provide.
  • Locate and protect the most endangered ecosystems
    and species, with emphasis on protecting plant
    biodiversity and ecosystem services.
  • Seek to restore as many degraded ecosystems as

Protecting global biodiversity hotspots is an
urgent priority
  • Some biodiversity scientists urge adoption of an
    emergency action strategy to identify and quickly
    protect biodiversity hotspots, areas especially
    rich in plant species that are found nowhere else
    and are in great danger of extinction .
  • These hotspots cover only a little more than 2
    of the earths land surface, they contain an
    estimated 50 of the worlds flowering plant
    species and 42 of all terrestrial species.
  • These hotspots are home for a large majority of
    the worlds endangered or critically endangered
    species, and one-fifth of the worlds population.

We can rehabilitate and restore ecosystems that
we have damaged
  • Almost every natural place on the earth has been
    affected or degraded to some degree by human
  • We can at least partially reverse much of this
    harm through ecological restoration the process
    of repairing damage caused by humans to the
    biodiversity and dynamics of natural ecosystems.
  • Examples of restoration include
  • replanting forests

We can rehabilitate and restore ecosystems that
we have damaged
  • restoring grasslands
  • restoring coral reefs
  • restoring wetlands and stream banks
  • reintroducing native species
  • removing invasive species
  • freeing river flows by removing dams.

We can rehabilitate and restore ecosystems that
we have damaged
  • Four steps to speed up repair operations include
    the following
  • Restoration.
  • Rehabilitation.
  • Replacement.
  • Creating artificial ecosystems.

We can rehabilitate and restore ecosystems that
we have damaged
  • Researchers have suggested a science-based,
    four-step strategy for carrying out most forms of
    ecological restoration and rehabilitation
  • Identify the causes of the degradation.
  • Stop the abuse by eliminating or sharply reducing
    these factors.
  • If necessary, reintroduce key species to help
    restore natural ecological processes.
  • Protect the area from further degradation and
    allow secondary ecological succession to occur.

We can share areas we dominate with other species
  • Reconciliation ecology is the science that
    focuses on inventing, establishing, and
    maintaining new habitats to conserve species
    diversity in places where people live, work, or
  • Examples include
  • Protecting local wildlife and ecosystems can
    provide economic resources for their communities
    by encouraging sustainable forms of ecotourism.

We can share areas we dominate with other species
  • Protecting vital insect pollinators such as
    native butterflies and bees by reducing the use
    of pesticides, planting flowering plants as a
    source of food for pollinating insect species,
    and building structures which serve as hives for
    pollinating bees.
  • Protecting bluebirds within human-dominated
    habitats where most of the bluebirds nesting
    trees have been cut down by using nesting boxes
    and keeping house cats away from nesting

Ways you can help sustain terrestrial biodiversity
How can we help to sustain aquatic biodiversity?
  • Section 9-6

The collapse of Canadas 500-year-old Atlantic
cod fishery
Before and after a trawler net
Major commercial fishing methods
Ways to manage fisheries more sustainably and
protect marine biodiversity
Three big ideas
  • The economic value of ecological services
  • We can sustain terrestrial biodiversity by
  • We can sustain aquatic biodiversity by

Human activities are destroying and degrading
aquatic biodiversity
  • Human activities have destroyed or degraded a
    large portion of the worlds coastal wetlands,
    coral reefs, mangroves, and ocean bottom, and
    disrupted many of the worlds freshwater
  • Rising sea levels are likely to destroy many
    coral reefs and flood some low-lying islands
    along with their protective coastal mangrove
  • Loss and degradation of many sea-bottom habitats
    caused by dredging operations and trawler fishing

Human activities are destroying and degrading
aquatic biodiversity
  • In freshwater aquatic zones, dam building and
    excessive water withdrawal from rivers for
    irrigation and urban water supplies destroy
    aquatic habitats, degrade water flows, and
    disrupt freshwater biodiversity.
  • The deliberate or accidental introduction of
    hundreds of harmful invasive species threatens
    aquatic biodiversity.
  • Thirty-four percent of the worlds known marine
    fish species and 71 of the worlds freshwater
    fish species face premature extinction.

Overfishing gone fishing fish gone
  • A fishery is a concentration of a particular wild
    aquatic species suitable for commercial
    harvesting in a given ocean area or inland body
    of water.
  • The fishprint is defined as the area of ocean
    needed to sustain the consumption of an average
    person, a nation, or the world.
  • Fifty-two percent of the worlds fisheries are
    fully exploited, 20 are moderately
    overexploited, and 28 are overexploited or

Overfishing gone fishing fish gone
  • Overharvesting has led to the collapse of some of
    the worlds major fisheries.
  • When overharvesting causes larger predatory
    species to dwindle, rapidly reproducing invasive
    species can more easily take over and disrupt
    ocean food webs.

CASE STUDY Industrial Fish Harvesting Methods
  • Industrial fishing fleets dominate the worlds
    marine fishing industry, using global satellite
    positioning equipment, sonar fish-finding
    devices, huge nets and long fishing lines,
    spotter planes, and gigantic refrigerated factory
    ships that can process and freeze their catches.
  • Trawler fishing is used to catch fish and
    shellfish by dragging a funnel-shaped net held
    open at the neck along the ocean bottom.
  • Purse-seine fishing, is used to catch
    surface-dwelling fish by using a spotter plane to
    locate a school the fishing vessel then encloses
    it with a large net called a purse seine.

CASE STUDY Industrial Fish Harvesting Methods
  • Longlining involves lines up to 130 kilometers
    (80 miles) long, hung with thousands of baited
    hooks to catch open-ocean fish species or bottom
  • Drift-net fishing catches fish with huge drifting
    nets that can hang as deep as 15 meters (50 feet)
    below the surface and extend to 64 kilometers (40
    miles) long.
  • Drift-nets can trap and kill large quantities of
    unwanted fish, called bycatch, along with marine
    mammals, sea turtles, and seabirds.
  • Almost one-third of the worlds annual fish catch
    by weight consists of bycatch species, which are
    mostly thrown overboard dead or dying.

We can protect and sustain marine biodiversity
  • Protecting marine biodiversity is difficult for
    several reasons.
  • The human ecological footprint and fishprint are
    expanding so rapidly into aquatic areas that it
    is difficult to monitor the impacts.
  • Much of the damage to the oceans and other bodies
    of water is not visible to most people.

We can protect and sustain marine biodiversity
  • Many people incorrectly view the seas as an
    inexhaustible resource that can absorb an almost
    infinite amount of waste and pollution and still
    produce all the seafood we want.
  • Most of the worlds ocean area lies outside the
    legal jurisdiction of any country and is thus an
    open-access resource and subject to

We can protect and sustain marine biodiversity
  • Several ways to protect and sustain marine
  • Protect endangered and threatened aquatic
  • Establish protected marine sanctuaries.
  • Protect whole marine ecosystems within a global
    network of fully protected marine reserves.

Taking an Ecosystem Approach to Sustaining
Aquatic Biodiversity
  • Strategies for applying the ecosystem approach to
    aquatic biodiversity include
  • Complete the mapping of the worlds aquatic
    biodiversity, identifying and locating as many
    plant and animal species as possible.
  • Identify and preserve the worlds aquatic
    biodiversity hotspots and areas where
    deteriorating ecosystem services threaten people
    and other forms of life.

Taking an Ecosystem Approach to Sustaining
Aquatic Biodiversity
  • Create large and fully protected marine reserves
    to allow damaged marine ecosystems to recover and
    to allow fish stocks to be replenished.
  • Protect and restore the worlds lakes and river
    systems (the most threatened ecosystems of all).
  • Initiate worldwide ecological restoration
    projects in systems such as coral reefs and
    inland and coastal wetlands.
  • Find ways to raise the incomes of people who live
    in or near protected lands and waters so that
    they can become partners in the protection and
    sustainable use of ecosystems.

Taking an Ecosystem Approach to Sustaining
Aquatic Biodiversity
  • The harmful effects of human activities on
    aquatic biodiversity and ecosystem services could
    be reversed over the next 2 decades if an
    ecosystem approach is implemented, at a cost one
    of penny per cup of coffee consumed in the world
    each year.