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Sustaining Biodiversity: The Ecosystem Approach

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Sustaining Biodiversity: The Ecosystem Approach Chapter 9 * Figure 11.7: Natural capital degradation. This graph illustrates the collapse of Canada s 500-year-old ... – PowerPoint PPT presentation

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Title: Sustaining Biodiversity: The Ecosystem Approach


1
Sustaining Biodiversity The Ecosystem Approach
  • Chapter 9

2
What are the major threats to forest ecosystems?
  • Section 9-1

3
2 types of forests
  • Two major types based on their age and structure
  • Old growth forest Uncut or regenerated primary
    forest that has not been seriously disturbed by
    human activities or natural disasters for several
    hundred years or more.
  • Second-growth forest A stand of trees resulting
    from secondary ecological succession that
    develops after the trees in an area have been
    removed by human activities such as clear-cutting
    for timber or cropland or by natural forces such
    as fire, hurricanes, or volcanic eruption.

4
The short rotation cycle of cutting and regrowth
of a monoculture tree plantation
5
Weak trees removed
25 yrs
Clear cut
30 yrs
15 yrs
Years of growth
Seedlings planted
5 yrs
10 yrs
Fig. 9-3a, p. 176
6
Forests provide many important economic and
ecological services
7
Unsustainable logging is a major threat to forest
ecosystems
  • Problems associated with harvesting trees
  • Increased erosion and sediment runoff into
    waterways.
  • Habitat fragmentation.
  • Loss of biodiversity.
  • Forest exposure to invasion by nonnative pests,
    diseases, and wildlife species.

http//www.youtube.com/watch?vM4jhjt1_eyM
Know this!
http//www.youtube.com/watch?v7rWcgxFVnjY
8
Unsustainable logging is a major threat to forest
ecosystems
  • Methods of harvesting trees
  • Selective cutting.
  • Clear-cut.
  • Strip cutting.

9
Three major tree harvesting methods
10
(a) Selective cutting
Clear stream
Fig. 9-6a, p. 179
11
(b) Clear-cutting
Muddy stream
Fig. 9-6b, p. 179
12
(c) Strip cutting
Cut 1 year ago
Uncut
Dirt road
Cut 310 years ago
Uncut
Clear stream
Fig. 9-6c, p. 179
13
  • Know the best type of logging (strip cutting) and
    the differences between the 3 types.

14
Aerial view showing clear-cut logging, Washington
state
15
Fires
  1. Surface fires
  2. Crown fires

16
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
    escape.
  • 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.

17
Fire can threaten or benefit forest ecosystems
  1. Releases seeds from the cones of lodgepole pines.
  2. Stimulates the germination of certain tree seeds
    (e.g. giant sequoia and jack pine).
  3. Helps to control tree diseases and insects.

18
Crown Fires
  • 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.

19
Surface fires and crown fires
20
Deforestation
  • Deforestation is the temporary or permanent
    removal of large expanses of forest for
    agriculture, settlements, or other uses.

21
Harmful effects of deforestation
22
  • What are the problems associated with
    deforestation?

23
Forest cover in the U.S.
24
Carolina Parakeet
The Carolina Parakeet was the only parrot species
native to the eastern United States. It was found
from southern New York and Wisconsin to Kentucky,
Tennessee and the Gulf of Mexico, and lived in
old forests along rivers.
25
Tropical forests are disappearing rapidly
  • At least half of the worlds known species of
    terrestrial plants and animals live in tropical
    forests.

26
Tropical Forests
  • 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.

27
Causes of tropical deforestation population
growth
  • There are a number of interconnected underlying
    and direct causes.
  • Pressures from population growth and poverty,
    push subsistence farmers and the landless poor
    into tropical forests, where they try to grow
    enough food to survive.

28
Causes of tropical deforestation government
subsidies
  • Government subsidies can accelerate the direct
    causes such as logging and ranching by reducing
    the costs of timber harvesting, cattle grazing,
    and the creation of vast plantations of crops
    such as soybeans.

29
Causes of tropical deforestation
  • Tropical forests in the Amazon and other South
    American countries are cleared/burned for cattle
    grazing and large soybean plantations.

30
Causes of tropical deforestation
  • In Southeast Asia, tropical forests are being
    replaced with vast plantations of oil palm, whose
    oil is used in cooking, cosmetics, and biodiesel
    fuel for motor vehicles.

31
Causes of tropical deforestation
  • In Africa, people struggle to survive by clearing
    plots for small-scale farming and by harvesting
    wood for fuel, which is causing deforestation on
    that continent.

32
Major underlying and direct causes of the
destruction and degradation of tropical forests
33
Possible test question
  • List 3 causes of deforestion

34
How should we manage and sustain forests?
  • Section 9-2

35
Ways to grow and harvest trees more sustainably
Know this!
36
We can improve the management of forest fires
  • In the United States, the Smokey Bear educational
    campaign has
  • prevented countless forest fires, saved many
    lives and prevented billions of dollars in loss
    of trees, wildlife, and human structures.
  • convinced the public that all forest fires are
    bad and should be prevented or put out.

37
We can improve the management of forest fires
  • Strategies for reducing fire-related harm
  • Prescribed burns are small, contained surface
    fires to remove flammable small trees and
    underbrush in the highest-risk forest areas.

Know this!
38
  • Be able to list the advantages and disadvantages
    of forest fires.

39
  • Allow some fires on public lands to burn, thereby
    removing flammable underbrush and smaller trees,
    as long as the fires do not threaten human
    structures and life. Protect houses/buildings in
    fire-prone areas by thinning a zone of about 60
    meters (200 feet) around them and eliminating the
    use of flammable building materials such as
    wooden shingles.
  • Thin fire-prone areas by clearing small
    fire-prone trees and underbrush under careful
    environmental controls.

40
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41
Construction Materials
  • Reduce inefficient use of construction materials,
    excess packaging, overuse of junk mail,
    inadequate paper recycling, and failure to reuse
    or find substitutes for wooden shipping
    containers.

42
We can reduce the demand for harvested trees
  • Paper can be made from fiber that does not come
    from trees.

http//www.elephantdungpaper.com/
43
Debt for nature swap
  • Debt-for-nature swap can make it financially
    attractive for countries to protect their
    tropical forests.
  •  financial transactions in which a portion of
    a developing nation's foreign debt is forgiven in
    exchange for local investments in environmental
    conservation measures.

http//www.youtube.com/watch?vcCoyohdoO-A
44
Conservation concessions
  • Conservation concessions occur when governments
    or private conservation organizations pay nations
    for agreeing to preserve their natural resources.

45
Ways to reduce tropical deforestation
  • Consumers can reduce the demand for products that
    are supplied through illegal and unsustainable
    logging in tropical forests.
  • For building projects, use recycled waste lumber
    or wood alternatives, such as recycled plastic
    building materials and bamboo.
  • Reduce the use of throwaway paper products and
    replace them with reusable plates, cups, and
    cloth napkins and handkerchiefs.
  • Individuals can plant trees.

46
Ways to protect tropical forests and use them
more sustainably
47
How should we manage and sustain grasslands?
  • Section 9-3

48
Ecological Services of Grasslands
  • Grasslands provide many important ecological
    services, including
  • soil formation,
  • erosion control,
  • nutrient cycling,
  • storage of atmospheric carbon dioxide in biomass,
  • maintenance of biodiversity.

49
Rangelands
  • Rangelands are unfenced grasslands in temperate
    and tropical climates that supply forage, or
    vegetation, for grazing (grass-eating) and
    browsing (shrub-eating) animals.

50
Overgrazing
  • Overgrazing occurs when too many animals graze
    for too long and exceed the carrying capacity of
    a rangeland area.

51
Left of fence overgrazed landRight lightly
grazed land
52
We can manage rangelands more sustainably
  • Control the number of grazing animals and the
    duration of their grazing in a given area so the
    carrying capacity of the area is not exceeded.

53
Restoration via secondary ecological succession
54
How should we manage and sustain parks and nature
reserves?
  • Section 9-4

55
National parks face many environmental threats
  • Many parks suffer from invasions by nonnative
    species that compete with and reduce the
    populations of native species.
  • Some parks are so popular that large numbers of
    visitors are degrading the natural features that
    make them attractive.

56
What is the ecosystem approach to sustaining
biodiversity?
  • Section 9-5

57
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.
  • Seek to restore as many degraded ecosystems as
    possible.
  • Make development biodiversity-friendly by
    providing financial incentives (tax-breaks) to
    private landowners who agree to help protect
    endangered ecosystems.

58
Protecting global biodiversity hotspots
  • Biodiversity hotspots areas especially rich in
    plant species that are found nowhere else and are
    in great danger of extinction.
  • Know this term!

59
Biodiversity hotspots
60
We can rehabilitate and restore ecosystems that
we have damaged
  • We can reverse much of this harm through
    ecological restoration the process of repairing
    damage caused by humans to the biodiversity and
    dynamics of natural ecosystems.

61
We can rehabilitate and restore ecosystems that
we have damaged
  • Examples of restoration include
  • replanting forests
  • restoring grasslands
  • restoring coral reefs
  • restoring wetlands and stream banks
  • reintroducing native species
  • removing invasive species
  • freeing river flows by removing dams.

62
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.

63
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64
Ways you can help sustain terrestrial biodiversity
65
How can we help to sustain aquatic biodiversity?
  • Section 9-6

66
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
    ecosystems.
  • Rising sea levels are likely to destroy many
    coral reefs and flood some low-lying islands
    along with their protective coastal mangrove
    forests.
  • Loss and degradation of many sea-bottom habitats
    caused by dredging operations and trawler fishing
    boats.

67
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.

68
Before and after a trawler net
69
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.

http//www.youtube.com/watch?vVxacxShp3LY
70
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.

71
The collapse of Canadas 500-year-old Atlantic
cod fishery
72
Ways to manage fisheries more sustainably and
protect marine biodiversity
Know!
73
Marine Reserves
  • http//www.youtube.com/watch?v9_-BdqS54q8

74
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