Transcript Human_Ecology_files/Sustaining Biodiversity

Sustaining Terrestrial
Biodiversity
Core Case Study:
Reintroducing Wolves to Yellowstone
 Endangered

1850-1900 two million
wolves were destroyed.
 Keystone



Species
Species
Keeps prey away from open
areas near stream banks.
Vegetation reestablishes.
Species diversity expands.
Figure 10-1
HUMAN IMPACTS ON
TERRESTRIAL BIODIVERSITY
 We
have depleted
and degraded some
of the earth’s
biodiversity and these
threats are expected
to increase.
Figure 10-2
Why Should We Care About
Biodiversity?
 Use
Value: For the
usefulness in terms
of economic and
ecological services.
 Nonuse Value:
existence, aesthetics,
bequest for future
generations.
Figure 10-3
MANAGING AND SUSTAINING
FORESTS
 Forests
provide a
number of ecological
and economic services
that researchers have
attempted to estimate
their total monetary
value.
Figure 10-4
Types of Forests
 Old-growth
forest: uncut
or regenerated forest that
has not been seriously
disturbed for several
hundred years.


22% of world’s forest.
Hosts many species with
specialized niches.
Figure 10-5
Types of Forests
 Second-growth
forest: a stand of trees
resulting from natural secondary succession.
 Tree plantation: planted stands of a
particular tree species.
Figure 10-6
Weak trees
removed
Clear cut
25
30
Seedlings
planted
15
Years of growth
10
5
Fig. 10-6, p. 195
Global Outlook:
Extent of Deforestation
 Human
activities
have reduced the
earth’s forest cover
by as much as half.
 Losses are
concentrated in
developing
countries.
Figure 10-7
How Would You Vote?
To conduct an instant in-class survey using a classroom response
system, access “JoinIn Clicker Content” from the PowerLecture main
menu for Living in the Environment.
 Should
there be a global effort to sharply
reduce the cutting of old-growth forests?


a. Yes. Old-growth forests can only be saved by
rapid international action and the setting aside of
large reserves of the forests.
b. No. Only local citizens and not global efforts
led by the UN can save these forests.
Case Study: Deforestation and the
Fuelwood Crisis
 Almost
half the people in the developing
world face a shortage of fuelwood and
charcoal.


In Haiti, 98% of country is deforested.
MIT scientist has found a way to make charcoal
from spent sugarcane.
Harvesting Trees
 Building
roads into previously inaccessible
forests paves the way for fragmentation,
destruction, and degradation.
Figure 10-8
Harvesting Trees
 Trees
can be harvested
individually from diverse
forests (selective cutting),
an entire forest can be cut
down (clear cutting), or
portions of the forest is
harvested (e.g. strip
cutting).
Figure 10-9
Harvesting Trees
Effects of clear-cutting in the
state of Washington, U.S.
Figures 10-10 and 10-11
Solutions
 We
can use forests
more sustainably by
emphasizing:



Economic value of
ecological services.
Harvesting trees no
faster than they are
replenished.
Protecting old-growth
and vulnerable areas.
Figure 10-12
CASE STUDY:
FOREST RESOURCES AND
MANAGEMENT IN THE U.S.
 U.S.
forests cover more area than in 1920.
 Since the 1960’s, an increasing area of old
growth and diverse second-growth forests
have been clear-cut.



Often replace with tree farms.
Decreases biodiversity.
Disrupts ecosystem processes.
Types and Effects of Forest Fires

Depending on their intensity, fires can benefit or
harm forests.


Burn away flammable ground material.
Release valuable mineral nutrients.
Figure 10-13
Solutions:
Controversy Over Fire Management
 To



reduce fire damage:
Set controlled surface fires.
Allow fires to burn on public lands if they don’t
threaten life and property.
Clear small areas around property subject to fire.
Solutions:
Controversy Over Fire Management
 In
2003, U.S. Congress passed the Healthy
Forest Restoration Act:



Allows timber companies to cut medium and
large trees in 71% of the national forests.
In return, must clear away smaller, more fireprone trees and underbrush.
Some forest scientists believe this could increase
severe fires by removing fire resistant trees and
leaving highly flammable slash.
How Would You Vote?
To conduct an instant in-class survey using a classroom response
system, access “JoinIn Clicker Content” from the PowerLecture main
menu for Living in the Environment.
 Do
you support repealing or modifying the
Healthy Forests Restoration Act of 2003?


a. Yes. Local officials and scientists are probably
most qualified to manage their local forests.
b. No. The initiative favors the timber companies
rather than effectively protecting and managing
the forests.
Controversy over Logging in U.S. National
Forests
 There
has been an
ongoing debate over
whether U.S.
national forests
should be primarily
for:




Timber.
Ecological services.
Recreation.
Mix of these uses.
Figure 10-14
Solutions:
Reducing Demand for Harvest Trees
 Tree
harvesting can
be reduced by
wasting less wood
and making paper
and charcoal fuel
from fibers that do
not come from trees.

Kenaf is a promising
plant for paper
production.
Figure 10-15
American Forests in a Globalized
Economy
 Timber
from tree plantations in temperate
and tropical countries is decreasing the need
for timber production in the U.S.



This could help preserve the biodiversity in the
U.S. by decreasing pressure to clear-cut oldgrowth and second-growth forests.
This may lead to private land owners to sell less
profitable land to developers.
Forest management policy will play a key role.
CASE STUDY: TROPICAL
DEFORESTATION
 Large
areas of ecologically and
economically important tropical forests are
being cleared and degraded at a fast rate.
Figure 10-16
CASE STUDY: TROPICAL
DEFORESTATION
 At
least half of the
world’s terrestrial plant
and animal species live
in tropical rain forests.
 Large areas of tropical
forest are burned to
make way for cattle
ranches and crops.
Figure 10-17
Why Should We Care about the Loss
of Tropical Forests?
 About
2,100 of the 3,000 plants identified by
the National Cancer Institute as sources of
cancer-fighting chemicals come from tropical
forests.
Figure 10-18
Causes of Tropical Deforestation and
Degradation
 Tropical
deforestation
results from a
number of
interconnected
primary and
secondary causes.
Figure 10-19
Solutions
Sustaining Tropical Forests
Prevention
Protect most diverse and endangered
areas
Restoration
Reforestation
Educate settlers about sustainable
agriculture and forestry
Phase out subsidies that encourage
unsustainable forest use
Add subsidies that encourage
sustainable forest use
Rehabilitation of degraded
areas
Protect forests with debt-for-nature
swaps and conservation easements
Certify sustainably grown timber
Reduce illegal cutting
Reduce poverty
Slow population growth
Concentrate farming and
ranching on already-cleared
areas
Fig. 10-20, p. 207
Kenya’s Green Belt Movement:
Individuals Matter
 Wangari
Maathai
founded the Green Belt
Movement.
 The main goal is to
organize poor women to
plant (for fuelwood) and
protect millions of trees.
 In 2004, awarded Nobel
peace prize.
Figure 10-10A
MANAGING AND SUSTAINING
GRASSLANDS
 Almost
half of the world’s livestock graze on
natural grasslands (rangelands) and
managed grasslands (pastures).
 We can sustain rangeland productivity by
controlling the number and distribution of
livestock and by restoring degraded
rangeland.
MANAGING AND SUSTAINING
GRASSLANDS
 Overgrazing
(left)
occurs when too
many animals
graze for too long
and exceed
carrying capacity
of a grassland
area.
Figure 10-21
MANAGING AND SUSTAINING
GRASSLANDS
 Example
of restored area along the San
Pedro River in Arizona after 10 years of
banning grazing and off-road vehicles.
Figure 10-22
Case Study: Grazing and Urban
Development in the American West
 Ranchers,
ecologists, and environmentalists
are joining together to preserve the
grasslands on cattle ranches.


Paying ranchers conservation easements
(barring future owners from development).
Pressuring government to zone the land to
prevent development of ecologically sensitive
areas.
NATIONAL PARKS
 Countries
have established more than 1,100
national parks, but most are threatened by
human activities.




Local people invade park for wood, cropland,
and other natural resources.
Loggers, miners, and wildlife poachers also
deplete natural resources.
Many are too small to sustain large-animal
species.
Many suffer from invasive species.
Case Study: Stresses on U.S.
National Parks
 Overused
due to
popularity.
 Inholdings (private
ownership) within
parks threaten
natural resources.
 Air pollution.
Figure 10-23
 Suggestions
for
sustaining and
expanding the
national park
system in the
U.S.
Figure 10-24
NATURE RESERVES
 Ecologists
call for protecting more land to
help sustain biodiversity, but powerful
economic and political interests oppose doing
this.



Currently 12% of earth’s land area is protected.
Only 5% is strictly protected from harmful human
activities.
Conservation biologists call for full protection of
at least 20% of earth’s land area representing
multiple examples of all biomes.
How Would You Vote?
To conduct an instant in-class survey using a classroom response
system, access “JoinIn Clicker Content” from the PowerLecture main
menu for Living in the Environment.
 Should
at least 20% of the Earth's land area
be strictly protected from economic
development?


a. No. Such protections would encourage people
to poach and illegally extract resources from the
expanded reserves.
b. Yes. The project is desperately needed to
protect the Earth's biodiversity.
NATURE RESERVES
 Large
and medium-sized reserves with buffer
zones help protect biodiversity and can be
connected by corridors.
 Costa
Rica has
consolidated its parks
and reserves into 8
megareserves
designed to sustain
80% if its biodiversity.
Figure 10-10B
Guanacaste
Nigaragua
Caribbean Sea
Llanuras de
Tortuguero
Costa
Rica
Arenal
Bajo
Tempisque
La Amistad
Panama
Cordillera Volcanica Central
Pacifico Central
Peninsula Osa
Pacific Ocean
Fig. 10-B, p. 213
NATURE RESERVES
A
model biosphere
reserve that
contains a protected
inner core
surrounded by two
buffer zones that
people can use for
multiple use.
Figure 10-25
NATURE RESERVES
 Geographic
Information System (GIS)
mapping can be used to understand and
manage ecosystems.


Identify areas to establish and connect nature
reserves in large ecoregions to prevent
fragmentation.
Developers can use GIS to design housing
developments with the least environmental
impact.
NATURE RESERVES
 We
can prevent or slow down losses of
biodiversity by concentrating efforts on
protecting global hot spots where significant
biodiversity is under immediate threat.
 Conservation biologists are helping people in
communities find ways to sustain local
biodiversity while providing local economic
income.

34 hotspots identified by ecologists as important and
endangered centers of biodiversity.
Figure 10-26
NATURE RESERVES
 Wilderness
is land legally set aside in a large
enough area to prevent or minimize harm
from human activities.
 Only a small percentage of the land area of
the United States has been protected as
wilderness.
ECOLOGICAL RESTORATION
 Restoration:
trying to return to a condition as
similar as possible to original state.
 Rehabilitation: attempting to turn a
degraded ecosystem back to being
functional.
 Replacement: replacing a degraded
ecosystem with another type of ecosystem.
 Creating artificial ecosystems: such as
artificial wetlands for flood reduction and
sewage treatment.
ECOLOGICAL RESTORATION
 Five
basic science-based principles for
ecological restoration:





Identify cause.
Stop abuse by eliminating or sharply reducing
factors.
Reintroduce species if necessary.
Protect area form further degradation.
Use adaptive management to monitor efforts,
assess successes, and modify strategies.
Will Restoration Encourage Further
Destruction?
 There
is some concern that ecological
restoration could promote further
environmental destruction and degradation.


Suggesting that any ecological harm can be
undone.
Preventing ecosystem damage is far cheaper
than ecological restoration.
How Would You Vote?
To conduct an instant in-class survey using a classroom response
system, access “JoinIn Clicker Content” from the PowerLecture main
menu for Living in the Environment.

Should we mount a massive effort to restore
ecosystems we have degraded even though this
will be quite costly?


a. No. Less expensive alternatives, such as
remediation, replacement, and the creation of
artificial ecosystems, should be readily considered.
b. Yes. Alternatives will probably not achieve the
same biodiversity as ecological restoration.
WHAT CAN WE DO?
 Eight





priorities for protecting biodiversity:
Take immediate action to preserve world’s
biological hot spots.
Keep intact remaining old growth.
Complete mapping of world’s biodiversity for
inventory and decision making.
Determine world’s marine hot spots.
Concentrate on protecting and restoring lake and
river systems (most threatened ecosystems).
WHAT CAN WE DO?



Ensure that the full range of the earths
ecosystems are included in global conservation
strategy.
Make conservation profitable.
Initiate ecological restoration products to heal
some of the damage done and increase share of
earth’s land and water allotted to the rest of
nature.
What Can You Do?
Sustaining Terrestrial Biodiversity
• Adopt a forest.
• Plant trees and take care of them.
• Recycle paper and buy recycled paper products.
• Buy sustainable wood and wood products.
• Choose wood substitutes such as bamboo furniture
and recycled plastic outdoor furniture, decking, and
fencing.
• Restore a nearby degraded forest or grassland.
• Landscape your yard with a diversity of plants
natural to the area.
• Live in town because suburban sprawl reduces
biodiversity.
Fig. 10-27, p. 219
Sustaining Aquatic
Biodiversity
Video: Whaling, Overfishing, Fishery
Management
 This
video clip is available in CNN Today
Videos for Environmental Science, 2004,
Volume VII. Instructors, contact your local
sales representative to order this volume,
while supplies last.
AQUATIC BIODIVERSITY
 We
know fairly little about the biodiversity of
the world’s marine and freshwater systems.


The greatest marine biodiversity occurs in coral
reefs, estuaries and the deep ocean floor.
Biodiversity is higher near the coast and surface
because of habitat and food source variety.
 The
world’s marine and freshwater systems
provide important ecological and economic
services.
HUMAN IMPACTS ON AQUATIC
BIODIVERSITY
 Human
activities have destroyed, disrupted
or degraded a large proportion of the world’s
coastal, marine and freshwater ecosystems.



Approximately 20% of the world's coral reefs
have been destroyed.
During the past 100 years, sea levels have risen
10-25 centimeters.
We have destroyed more than 1/3 of the world’s
mangrove forests for shipping lanes.
HUMAN IMPACTS ON AQUATIC
BIODIVERSITY
 Area
of ocean before and after a trawler net,
acting like a giant plow, scraped it.
Figure 12-2
HUMAN IMPACTS ON AQUATIC
BIODIVERSITY
 Harmful
invasive species are an increasing
threat to marine and freshwater biodiversity.

Bioinvaders are blamed for about 2/3 of fish
extinctions in the U.S. between 1900-2000.
 Almost
half of the world’s people live on or
near a coastal zone and 80% of ocean water
pollution comes from land-based human
activities.
Population Growth and Pollution
 Each
year plastic
items dumped from
ships and left as
litter on beaches
threaten marine
life.
Figure 12-3
Overfishing and Extinction:
Gone Fishing, Fish Gone
 About
75% of the world’s commercially
valuable marine fish species are over fished
or fished near their sustainable limits.




Big fish are becoming scarce.
Smaller fish are next.
We throw away 30% of the fish we catch.
We needlessly kill sea mammals and birds.
Fish farming
in cage
Trawl flap
Trawler
fishing
Spotter airplane
Sonar
Purse-seine fishing
Trawl
lines
Trawl bag
Long line
fishing
Fish
school
Drift-net fishing
Float Buoy
Lines with
hooks
Deep sea
aquaculture cage
Fish caught
by gills
Fig. 12-A, p. 255
Why is it Difficult to Protect Aquatic
Biodiversity?
 Rapid
increasing human impacts, the
invisibility of problems, citizen unawareness,
and lack of legal jurisdiction hinder protection
of aquatic biodiversity.



Human ecological footprint is expanding.
Much of the damage to oceans is not visible to
most people.
Many people incorrectly view the oceans as an
inexhaustible resource.
PROTECTING AND SUSTAINING
MARINE BIODIVERSITY
 Laws,
international treaties, and education
can help reduce the premature extinction of
marine species.
 Since 1989 the U.S. government has
required offshore shrimp trawlers to use turtle
exclusion devices.

Sea turtle tourism brings in almost three times as
much money as the sale of turtle products.
PROTECTING AND SUSTAINING
MARINE BIODIVERSITY
 Six
of the world’s
seven major turtle
species are
threatened or
endangered
because o human
activities.
Figure 12-4
Case Study: The Florida Manatee
and Water Hyacinths
 Manatee
can eat
unwanted Water
Hyacinths.
 Endangered due to:





Habitat loss.
Entanglement from fishing
lines and nets.
Hit by speed boats.
Stress from cold.
Low reproductive rate
Figure 12-B
Case Study: Commercial Whaling
 After
many of the
world’s whale
species were
overharvested,
commercial
whaling was
banned in 1960,
but the ban may
be overturned.
Figure 12-6
Case Study:
Commercial Whaling
 Despite
ban, Japan,
Norway, and Iceland kill
about 1,300 whales of
certain species for scientific
purposes.

Although meat is still sold
commercially.
Figure 12-5
Toothed whales
Sperm
whale
with
squid
Killer whale
Narwhal
Bottlenose dolphin
Baleen whales
Blue whale
Fin whale
Bowhead
whale
Right
whale
Sei whale
Humpback
whale
Gray whale
Minke whale
Fig. 12-5, p. 258
How Would You Vote?
To conduct an instant in-class survey using a classroom response
system, access “JoinIn Clicker Content” from the PowerLecture main
menu for Living in the Environment.
 Should
carefully controlled commercial
whaling be resumed for species with
populations of 1 million or more?


No. The hunting of whales is no longer
necessary and simply encourages disrespect for
these intelligent giants.
Yes. Some whale species have recovered and
products from them are valuable resources for
humans.
PROTECTING AND SUSTAINING
MARINE BIODIVERSITY
 Fully
protected marine reserves make up less
than 0.3% of the world’s ocean area.

Studies show that fish populations double, size
grows by almost a third, reproduction triples and
species diversity increases by almost one fourth.
 Some
communities work together to develop
integrated plans for managing their coastal
areas.
Revamping Ocean Policy
 Two
recent studies called for an overhaul of
U.S. ocean policy and management.






Develop unified national policy.
Double federal budget for ocean research.
Centralize the National Oceans Agency.
Set up network of marine reserves.
Reorient fisheries management towards
ecosystem function.
Increase public awareness.
MANAGING AND SUSTAINING
MARINE FISHERIES
 There
are a number of ways to manage
marine fisheries more sustainably and protect
marine biodiversity.
 Some fishing communities regulate fish
harvests on their own and others work with
the government to regulate them.

Modern fisheries have weakened the ability of
many coastal communities to regulate their own
fisheries.
Solutions
Managing Fisheries
Fishery Regulations
Bycatch
Set catch limits well below the
maximum sustainable yield
Use wide-meshed nets to allow
escape of smaller fish
Improve monitoring and enforcement
of regulations
Economic Approaches
Use net escape devices for sea
birds and sea turtles
Sharply reduce or eliminate fishing
subsidies
Ban throwing edible and
marketable fish back into the sea
Aquaculture
Charge fees for harvesting fish and shellfish
from publicly owned offshore waters
Restrict coastal locations for fish
farms
Certify sustainable fisheries
Protected Areas
Control pollution more strictly
Establish no-fishing areas
Depend more on herbivorous fish
species
Establish more marine protected areas
Nonnative Invasions
Rely more on integrated coastal
management
Kill organisms in ship ballast water
Consumer Information
Label sustainably harvested fish
Publicize overfished and threatened species
Filter organisms from ship ballast
water
Dump ballast water far at sea and
replace with deep-sea water
Fig. 12-7, p. 261
PROTECTING, SUSTAINING, AND
RESTORING WETLANDS
 Requiring
government permits for filling or
destroying U.S. wetlands has slowed their
loss, but attempts to weaken this protection
continue.
Figure 12-8
Solutions
Protecting Wetlands
Legally protect existing wetlands
Steer development away from existing wetlands
Use mitigation banking only as a last resort
Require creation and evaluation of a new wetland before
destroying an existing wetland
Restore degraded wetlands
Try to prevent and control invasions by nonnative species
Fig. 12-9, p. 264
Case Study:
Restoring the Florida Everglades
 The
world’s largest ecological restoration
project involves trying to undo some of the
damage inflicted on the Everglades by
human activities.




90% of park’s wading birds have vanished.
Other vertebrate populations down 75-95%.
Large volumes of water that once flowed through
the park have been diverted for crops and cities.
Runoff has caused noxious algal blooms.
Restoring the
Florida
Everglades
 The
project has
been attempting
to restore the
Everglades and
Florida water
supplies.
Figure 12-10
PROTECTING, SUSTAINING, AND
RESTORING LAKES AND RIVERS
 Lakes
are difficult to manage and are
vulnerable to planned or unplanned
introductions of nonnative species.
 For decades, invasions by nonnative species
have caused major ecological and economic
damage to North America’s Great lakes.

Sea lamprey, zebra mussel, quagga mussel,
Asian carp.
PROTECTING, SUSTAINING, AND
RESTORING LAKES AND RIVERS
 Dams
can provide many human benefits but
can also disrupt some of the ecological
services that rivers provide.



119 dams on Columbia River have sharply
reduced (94% drop) populations of wild salmon.
U.S. government has spent $3 billion in
unsuccessful efforts to save the salmon.
Removing hydroelectric dams will restore native
spawning grounds.
Natural Capital
Ecological Services of Rivers
• Deliver nutrients to sea to help sustain
coastal fisheries
• Deposit silt that maintains deltas
• Purify water
• Renew and renourish wetlands
• Provide habitats for wildlife
Fig. 12-11, p. 267
How Would You Vote?
To conduct an instant in-class survey using a classroom response
system, access “JoinIn Clicker Content” from the PowerLecture main
menu for Living in the Environment.

Should federal efforts to rebuild wild salmon
populations in the Columbia River Basin be
abandoned?


a. No. Restoring salmon populations is critical for the
environmental health of the river and surrounding
forests.
b. Yes. The restoration program would create
unnecessary and severe economic hardships for
local residents.
PROTECTING, SUSTAINING, AND
RESTORING LAKES AND RIVERS
 We
can help sustain freshwater fisheries by
building and protecting populations of
desirable species, preventing over-fishing,
and decreasing populations of less desirable
species.
 A federal law helps protect a tiny fraction of
U.S. wild and scenic rivers from dams and
other forms of development.

National Wild and Scenic Rivers Act (1968).