Transcript Chapter 25: Sustaining Wild Species - The Official Site

Chapter 23
Sustaining Ecosystems:
Land Use, Conservation, and
Management
How were land resources in the US used between
the 1400’s and 1900’s?
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In the 1400’s to the 1500’s
North America was populated
with diverse groups of
indigenous people who
practiced mostly sustainable
forms of hunting, gathering, and
use of wild resources
When European colonists
settled they cleared the land,
planted it, and exploited it for its
resources as quickly as
possible. They had no concern
for waste because they
believed there would always be
more.
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The belief that North America’s
resources were unlimited
prevailed almost until 1900
when people started to become
more concerned about
environmental and public health
hazards due to rapidly growing
industrialized cities.
What role did the government play in resource conservation
between 1900 and 1930?
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When Theodore Roosevelt became president he designated public land
as wildlife refuges and tripled the size of forest reserves.
In 1905 Congress created the US Forest Service to manage and protect
the forest reserves
The principle of sustainable yield and multiple use were employed
In 1912 Congress created the US National Park System
Between 1900 and 1927 public health boarders were established in most
cities and governments started to pay more attention to issues pertaining
to public health.
In 1933 the Civilian Conservation Corps was formed to provide jobs for 2
million unemployed people by planting trees, developing parks and
recreation areas, and protecting wildlife
Federal government built and operated large dams, including Hoover Dam
Government’s role in resource conservation
between 1930 and 1960
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Taylor grazing Act of 1934- required permits and fees for the use of
federal government lands and limited the number of livestock that
could be grazed
Migratory Bird Hunting Stamp Act of 1934- required that hunters buy
duck hunting licenses raising millions for waterfowl research and the
purchase of lands for wildlife refuges.
Soil conservation Service of 1935- established to address soil erosion
Federal Aid in Wildlife Restoration Act of 1937- raised more than 2.2
billion to buy land for wildlife conservation
In 1940 US Fish and Wildlife Service was established
Between 1933 and 1960 public health boards and agencies were
established at the municipal state and federal levels. Education about
health issues were emphasized.
Major Environmental Developments took
place between 1960 and 1980
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Rachel Carson published Silent Spring in 1962 pertaining to air,
water , and wildlife pollution from pesticides, which brought the
quality of air, water, soil, and wildlife to the public attention.
In 1964 the Wilderness Act was passed by Congress,
authorizing the government to protect undeveloped tracts of
public land for the national good
In 1976 the Federal land policy and Management Act gave the
Bureau authority to manage public land
Congress created the Department of Energy between 1977 and
1981 developing a long range energy plan, to reduce countries
dependence on imported oil.
Ecological Integrity
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The goals of conservation
biology are to investigate the
human impact on biodiversity
and to develop practical
approaches to preserving
biodiversity.
Ecological Integrity – the
conditions and natural
processes that generate and
maintain biodiversity and allow
evolutionary change as a key
mechanism for adapting the
changes in environmental
conditions.
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Ecological Health –
described in terms of the
degree to which its
biodiversity and ecological
integrity remain in tact.
The scientific approach
recognizes that saving
wildlife means saving their
habitats and not disturbing
the complex interactions
among species in an
ecosystem.
U.S. Public Lands
Multiple-use Lands:
 The 156 forest and 20 grasslands of the National Forest System
are managed by the U.S. Forest Service.
 This land is supposed to be managed using two principles:
sustainable yield and multiple use.
Moderately Restricted-use Lands:
 The 508 National Wildlife Refuges are managed by the U.S. Fish
and Wildlife Service and24% of this land is designated as
wilderness.
 Most of these protect habitat and breeding areas for water fowl an
big game to provide the harvestable supply for hunters; a few
protect endangered species from extinction.
Restricted-use Lands:
 The goals of the 375 units of the National Parks Systems are te
preserve scenic and natural landscapes, preserve and interpret
the country’s historic and cultural heritage, protect wildlife habitat
and wilderness areas, and provide certain types of recreation.
Managing and Sustaining Rangelands
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Almost half of the earth’s ice-free land is rangeland: land
that supplies vegetation for grazing animals and that is not
intensively managed.
About 42 % of the world’s range- land is used for grazing
livestock; much of the rest is too dry, cold or remote from
population centers to be grazed by large numbers of
livestock.
Rangeland provides forage for large numbers of large
herbivores; provides habitats for a variety of wild plants and
animal species
Overgrazing
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Overgrazing occurs when too many animals
graze for too long and exceed the carrying
capacity of the grassland area.
It lowers the productivity of vegetation and
changes the number and types of plants in
an area
Overgrazing is the major cause of
desertification in arid and semi-arid lands.
Heavy overgrazing compacts the soil, which
diminishes its capacity to hold water and to
regenerate itself.
Riparian Zones
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Riparian zones are thin strips of lush
vegetation along streams
These zones help prevent floods by storing
and releasing water slowly from spring runoff
and summer storms
65-75% of the wildlife in the western United
States is totally dependent upon riparian
habitats.
Rangeland Management
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The primary goal of rangeland management is to maximize
livestock productivity without overgrazing rangeland
vegetation.
Stocking rate is the most widely-used method so that it
does not exceed an area’s carrying capacity.
Both the numbers and distribution of livestock on a
rangeland must be controlled to prevent overgrazing.
Continuous grazing occurs throughout the year and is
popular because it is easy to manage and reduces costs by
requiring little livestock handling and fencing.
Deferred-rotation grazing involves moving livestock
between two or more rangelands to allow perennial grass to
recover from the effects of grazing.
Our National Parks
Today, over 1,100 national parks larger than 2,500 hectares each are
located in more than 120 countries. The U.S.National Parks System is
dominated by 54 National Parks. Most State Parks are located near
urban areas and thus are more heavily used than National Parks.
Threats to the Parks:
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Popularity
Noise
Traffic hams
Litter
Vandalism
Poaching
Deteriorating trails
Polluted water
Garbage piles
crime
Increased number of roads, cars and annual recreational visits
Wilderness
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Protecting biodiversity and ecological integrity
means protecting wildness.
One way to do this is to protect undeveloped lands
from exploitation by setting them aside as
wilderness.
A wilderness should contain at least 4,000 square
kilometers, otherwise, if can be affected by air, water,
and noise pollution from nearby human activities.
Wilderness areas provide mostly undisturbed
habitats for wildlife, plants and animals, protect diver
biomes from damage and provide a laboratory in
which we can discover more about how nature
works.
Gap Analysis
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Gap analysis has been developed to determined how
adequately native plants and animal species and natural
communities are protected by the existing network of
conservation lands.
Species and communities not adequately represented in
existing conservation lands constitute conservation gaps.
The idea is to identify these gaps and then eliminate them
in a proactive manner through the establishment of new
reserves or changing land management practices.
Forest Types and Importance
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Three general types of forest: tropical, temperate and polar.
Since agriculture began about 10,000 years ago, human
activities have reduced the earth’s forest cover by abut one
quarter.
Old-growth forest: uncut forest and regenerated forest that have
not been seriously disturbed for several hundreds or thousands
of years.
Second-growth forest: stands of trees resulting from secondary
ecological succession after cutting
Forest provide lumber for housing, biomass for fuel wood, pulp
for paper, medicines, and other products.
The U.S. is the world’s largest importer of wood products.
Forests influence climate and are vital to the global carbon
cycle.
Why Should we Care About Tropical Forests?
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The plight of tropical forests
is considered one of the
most serious environmental
problems because these
forests are home to 50-90%
of the earth’s terrestrial
species.
These forests supply onehalf of the world’s annual
harvest of hardwood,
hundreds of food products,
and materials such as natural
latex, (rubber), and essential
oils.
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25% of the worlds
prescription drugs are
derived from plants that grow
in tropical rainforests
70 % of the 3,000 plants
identified as sources of
cancer-fighting chemicals
come from these forests.
Fuelwood Crisis and Developing
Countries
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In 1998, about 2.2 billion
people in 63 developing
countries either could not
get enough fuelwood to
meet their basic needs, or
were forced to meet their
needs by using wood
faster than it was being
replenished.
As burning wood to boil
water becomes an
unaffordable luxury,
waterborne infectious
diseases and death will
spread.
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Buying fuelwood can take
40% of a poor family’s
meager income.
By burning dried animal
dung and crop residues
for cooking and heating,
these fertizers never each
the soil, and cropland
productivity is reduced
creating degradation in the
land and further
malnutrition and hunger.
Fuelwood shortages are
driven by rapid population
growth and poverty.
23: Managing and Sustaining Forests
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About 25% of the world’s forests are managed for
wood production.
The total volume of wood produced by a particular
stand of forest varies as it goes through different
stages of growth and ecological succession.
Two Basic Forest Management Systems:
1. Even-aged management: trees in a given stand
are maintained at about the same age and size
2. Uneven-aged management: a variety of tree
species in a given stand are maintained at many
ages and sizes to foster natural regeneration
How are Trees Harvested?
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Selective cutting- intermediate-aged or mature trees in an
uneven-aged forest are cut singly or in small groups, creating
gaps no larger than the height of standing trees, which
encourages the growth of younger trees and reduces crowding
Shelter-wood cutting- removes all mature trees in two or
typically three cuttings over a period of about 10 years.
Seed-tree cutting- harvests nearly all of a stand’s trees in one
cutting, leaving a few uniformly distributed seed-producing trees
to regenerate the stand. (used for recreation)
Continued…
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Clear-cutting- Removal of all trees from an area in a
single cutting. The clear-cut area may be a whole
stand, a strip, or a series of patches. After all the
trees are cut, the site is usually reforested
Strip cutting- A variation of clear-cutting that can
allow a sustainable timber yield without widespread
destruction
Whole-tree harvesting- machine cuts trees at ground
level or uproots entire trees. These trees are
transported to a chipping machine in which huge
blades reduce the woods to small chips.
How Fires Affect Forest Ecosystems
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Surface fires- burn only undergrowth and leaf litter
on the forest floor. These fires kill seedlings and
small trees, but spare most mature trees
Crown fires- start on the ground but eventually burn
whole trees and leap from treetop to treetop. They
destroy vegetation, kill wildlife, lead to accelerated
soil erosion, and set back the clock of ecological
recovery by up to hundreds of years.
Prescribed burning- controlled ground fires to
prevent buildup of flammable material
23: Solutions: Reducing Tropical
Deforestation and Fuelwood Shortages
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Conservation biologists urge us to move rapidly to
protect areas of tropical forests that are rich in
unique species and in imminent danger- hot spots/
critical ecosystems
Environmentalists urge governments to reduce the
flow of the landless poor to tropical forests by
slowing population growth and discouraging the poor
from migrating to undisturbed tropical forests
Another suggestion is to use economic policies to
protect and sustain tropical forests- full-cost pricing,
debt-for-nature
22: Why Preserve Wild Species?
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The Values of Species (6)
Economic
Medical
Scientific
Ecological
Aesthetic
Recreational
The Economic and Medical Importance
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90% of today’s food crops were domesticated from
wild tropical plants
Wild plants domesticated from wild species supply
rubber, oil, dyes, fiber, paper, and lumber
80% of the world’s population relies on plants or
plant extracts for medicines
40% of all pharmaceuticals, worth at least $100
billion per year, owe their existence to the genetic
resources of wild plants, mostly from tropical
developing countries
The Scientific and Ecological
Importance
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Every species can help scientists understand
how life has evolved and functions, and how
it will continue to evolve on this planet.
Wild species supply us with food, recycle
nutrients to the agriculture, and help
generate and maintain soils. They also
produce oxygen and other gases, absorb late
climates and water supplies, reduce erosion
and flooding, and store solar energy.
Aesthetic and Recreational Importance
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Americans spend about $18.2 billion a year
to watch wildlife
Ecotourism- Wildlife Tourism- is the fastest
growing segment of the global travel industry
and generates an estimated $30 billion in
revenues each year.
22: The Rise and Fall of Species
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99.9% of all the species that have ever existed are
no extinct because of a combination of background
and mass extinction.
Background- A small number of species becoming
extinct at a low rate every year.
Mass Extinction- Abrupt rise in extinction rates
above the background level.
The lass mass extinction took place 65 million years
ago when the dinosaurs became extinct for reasons
that are hotly debated.
Is There and New Mass Extinction
Crisis?
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Currently 18,000-73,000 species become extinct
each year (natural background extinction rate 3-30
per year)
Three differences between the current mass
extinction and those of the past
1. The current extinction crisis is the first to be
caused by a single species: humans
2. The current mass wildlife extinction is taking place
in only a few decades, rather than over thousands to
millions of years.
Continued..
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3. Besides killing off species, we are
eliminating many biologically diverse
environmentalists such as tropical forests,
tropical coral reefs, wetlands, and estuaries
that in the past have served as evolutionary
centers for the recovery of biodiversity after a
mass extinction
Endangered and Threatened Species
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Three Levels of Extinction:
1. Local extinction occurs when a species is no
longer found in an area it once inhabited but is still
found elsewhere
2. Ecological extinction occurs when there are so
few members of a species left that it can no longer
play its ecological roles in the biological communities
where it is found
3. Biological extinction occurs when a species is no
longer found anywhere on the earth.
Threatened Species
American Alligator
Bald Eagle
Giant Panda
Continued…
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Endangered Species: has so few survivors
that the species could soon become extinct
over all or most of its natural range.
(Example- Giant Panda in central China)
Threatened Species: Still abundant in the
natural range but is declining in numbers and
is likely to become endangered. (ExampleGrizzly Bear)
Characteristics of Extinction-Prone
Species:
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Low reproductive rate
Specialized feeding habits
Feed at high trophic levels
Large size
Limited or specialized nesting or breeding areas
Found in only one place or region
Fixed migratory patterns
Preys on livestock or people
Behavioral Patterns
Extinct Species
Great Auk
Dodo
Passenger Pigeon
22: Causes of Depletion and Premature
Extinction of Wild Species
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1. Human population growth
2. Economic systems and policies that fail to
value the environment and its ecological
services
3. Greater per capita resource use as a
result of increasing affluence and economic
growth
Underlying Causes Lead to other more
direct causes of endangerment and
extinction of wild species such as…
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1. Habitat loss and degradation
2. Habitat fragmentation
3. Commercial hunting and poaching
4. Over fishing
5. Predator and pest control
6. Sale of exotic pets and decorative plants
7. Climate change and pollution
8. Deliberate or accidental introduction of nonnative
species into ecosystems.
22: Solutions: Protecting Wild Species
from Depletion and Extinction
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Three approaches to managing wildlife and
protecting biodiversity.
Ecosystem approach- aims to preserve
balanced populations of species in their
native habitats, establish legally protected
wilderness areas and wildlife reserves, and
eliminate or reduce the populations of
nonnative species
Continued…
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Species approach- based on protecting
endangered species by identifying them,
giving them legal protection, preserving and
managing their crucial habitats, propagating
them in captivity, and reintroducing them into
suitable habitats.
Continued…
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Wildlife management approach- manages
game species for sustained yield by using
laws to regulate hunting, establishing harvest
quotas, developing population management
plans, and using international treaties to
protect migrating game species.
Endangered Species Act
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The Endangered Species Act of 1973 is one
of the world’s toughest environmental laws.
It authorizes the National Marine Fisheries
Service to identify and list endangered and
threatened ocean species; the U.S. Fish and
Wildlife Service identifies and lists all other
endangered and threatened species.
These species cannot be hunted, killed,
collected or injured in the United States.
Rules and Regulations…
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Any decision by either agency to add or remove a
species from the list must be based on biology only.
The act forbids federal agencies to carry out, fund, or
authorize projects that would either jeopardize an
endangered species or destroy or modify the critical
habit it needs to survive.
Between 1973 and 1998, the number of U.S. species
included in the official endangered and threatened
species list increased from 92 to over 1,100 species.
(Highest State- Hawaii)
Continued…
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The USFWS or NMFS is supposed to
prepare a plan to help the species recover.
The act requires that all commercial
shipments of wildlife and wildlife products
enter or leave the country through one of
nine designated ports.
22: Wildlife Management
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Wildlife management entails manipulating wildlife populations
and their habitats for their welfare and for human benefit. It
includes preserving endangered and threatened wild species
and enforcing wildlife laws.
The first step in wildlife management is to decide which species
are to be managed in particular area, a decision that is a source
of much controversy.
After goals have been set, the wildlife manager must develop a
management plan. Ideally, this is based on the principles of
ecological succession, wildlife population dynamics, and an
understanding of the cover, food, water, space, and habitat
requirements of each species.
24: Fishery Management and
Protecting Marine Biodiversity
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Freshwater: This involves encouraging populations
of commercial and sport fish species and reducing or
eliminating populations of less desirable species.
Techniques include regulating time and length of
fishing seasons and the number and size of fish that
can be taken
Marine Fisheries: Set annual quotas and establish
rules for dividing the allowable catch among the
participating countries or state, limiting fishing
seasons, and regulating the type of fishing gear that
can be used to harvest a particular species.
24: The Whaling Industry
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Cetaceans- an order of mostly marine mammals
ranging in size from .9 to 30 meters. They are
divided into two groups: Toothed Whales (bite their
foods) and Baleen Whales (filter feeders)
Whales are easy to kill because of their large size
and their need to come to the surface to breathe.
The Blue Whale has come to the brink of biological
extinction. It is the largest animal in the world today.
Whales- The Blue Whale and the
Humpback…
Whales Continued… Sperm Whale