Download Biodiversity

Sustaining Wild Species
Chapter 16
Review:
Explain the difference in
genetic diversity, species
richness, and ecosystem
diversity.
What is Biological Diversity?
• What changes have occurred to change the
biodiversity of the earth?
– Background extinction
– Mass extinction
– Adaptive radiation
• What is different today?
Importance of Biodiversity
• Biologist estimate that for every 2,000
species that have ever lived, 1,999 of
them are extinct today.
• Currently species extinction is occurring
at a rate of 100 to 1,000 times the
natural rate of background extinction.
Why are Alligators Special?
• Using figure 16.2 in your text book, list the
role alligators play in their environment.
• What is the name for the role the alligator
plays?
• __________ _________ within an ecosystem
provides the ecosystem with resilience, the
ability to ______________.
Importance of Biodiversity
Economic: crop strains such as the winged
bean plant (page 355), paper, fiber, dyes,
lumber, oils
Importance of Biodiversity
Medical:
drug source, testing for toxicity and
drugs/vaccines
• 80% of the world’s population relies on plants or
plant extracts for medicines.
• At least 40% of all pharmaceuticals come from
the genetic resources of wild plants, mostly
tropical developing countries. Example:
anticancer drugs
• Rosy periwinkle produces chemicals that are
effective against certain cancers --- childhood
leukemia (page 354)
Importance of Biodiversity
scientific knowledge: how life evolved and
functions
genetic engineering – the incorporation of
genes from one organism into an entirely
different species.
*We have skills to transfer genes from one
organism to another but we do not have the
ability to make genes that encode for specific
traits. Why destroy the genetic diversity
when it may hold the solutions?
Importance of Biodiversity
Ecological services: nutrient cycling,
pollination, soil fertility, oxygen production,
climate moderation, waste recycling,
detoxification, pest control, gene
pool/evolution
Remember Earth’s
Capital????
Importance of Biodiversity
Aesthetic and
Recreational
• Ecotourism: wildlife
tourism
• Americans spend 3 times
more to watch wildlife
than to go to movies or
on professional sporting
events
Why Use the Precautionary
Principle?
Aldo Leopold (page 353)
• we have little understanding of the ecological
roles of the world’s identified 1.75 million
species
• use precautionary principle to prevent the
premature extinction of species as a result of
our activities . Estimates are that on average
50 - 200 species per day become extinct
(above the background extinction rate)
Keystone species
A species that is crucial in determining
the nature and structure of the entire
ecosystem in which it lives; other species
of a community depend on or are greatly
affected by the keystone species, whose
influence is much greater than would be
expected by its relative abundance.
These are most vulnerable
to habitat loss.
Why Use the Precautionary
Principle?
Ecosystems may lose their ability to support
many forms of life because of the
disappearance of local populations of key
organisms
Why Use the Precautionary
Principle?
Mathematical models indicate a time lag of
several generations between habitat loss and
extinction, primarily because habitat loss also
removes potential colonization sites….
If this is true, biologist may be grossly
underestimating the magnitude of
the current biodiversity meltdown!
Three Levels of Extinction
Local Extinction: when a species is no longer
found in an area it once inhabited but is still
found elsewhere in the world.
Three Levels of Extinction
Ecological Extinction: Where 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.
Sea Otter
Three Levels of Extinction
Biological Extinction: Occurs when a species is
no longer found anywhere on the earth.
Biological extinction is FOREVER!!!
Endangered vs. Threatened
• What is the difference in the terms
endangered and threatened?
• Endangered: has so few individual survivors
that the species could soon become extinct
over all or most of its natural range.
• Threatened: still abundant in its natural
range but is declining in numbers and is likely
to become endangered. Examples: grizzly
bear, southern sea otter, American alligator
Estimated extinction rate
Estimated Extinction Rates
• Average annual extinction rate of Mammal
and Bird species
– 8000 B.C - A.D. 1600 1 species per 1000
– 1600 – 1900 1 species every 4 years
– 1900 – 1975 1 species every year
Estimated Extinction Rates
• Extinction rate of All Species
– 1975
– 1985
– 1990
– 2000
several hundred
several thousand
at least 10,000
20,000 – 50,000
Threatened
Endangered
Extinct
Ten Characteristics of
Extinction-Prone Species
•
•
•
•
•
found in limited areas
small population size
low population density
large body size
specialized niches and feeding habits --- Giant
Panda (bamboo)
• low reproductive rates
Ten Characteristics of
Extinction-Prone Species
• fixed migrations
Flyway – An established route that ducks, geese,
and shorebirds
follow during
their annual
migrations.
Ten Characteristics of
Extinction-Prone Species
• feed at the top of long food chains or webs
• have high economic value to people
• need large territory :
The California Condor
(page 357)
Snow Leopard Coat
Three Root Causes of
Extinction of Wildlife:
• human population growth
• economic systems that don’t value
the environment
• exploitation, degradation of wildlife
habitats
Eight Human Activities Which Directly
Increase the Wildlife Extinction Rate:
• population growth
• poverty
• habitat loss
Example: Figure 16.9, page 360 The dusky
seaside sparrow found only in the marshes of
St. Johns River in Fla. became extinct in 1987
due to human destruction of its habitat.
What Type of Feedback Loop?
Eight Human Activities Which Directly
Increase the Wildlife Extinction Rate:
• habitat fragmentation
• hunting/poaching (Carolina Parakeet, Prairie
Dog)
Problems with Habitat
Fragmentation
• Increase exposed surface are making species
vulnerable to predators, fires, etc
• Patches are too small to support minimum breeding
population
• Fragmentation can create barriers that limit the
ability of some species to disperse and colonize new
area, find enough to eat, and find mates
Critical population density
• Must have minimum viable population size:
below this number the species’ survival may
be jeopardized because males and females
have a difficult time finding each other.
Problems are:
– Death rate exceeds birth rate as population falls
below its critical size
– Remaining small population can easily be wiped
out by fire, flood, disease
Critical population density
• Genetic diversity also decreases because the
resulting smaller gene pool and inbreeding reduce
population’s ability to respond to environmental
changes through natural selection
• An endangered species must number at least 10,000
and often more to maintain its evolutionary potential
for survival.
Eight Human Activities Which Directly
Increase the Wildlife Extinction Rate:
• uses as pets/ decorations
• climate change/pollution
Eight Human Activities Which Directly
Increase the Wildlife Extinction Rate:
• introduced species (alien species)
Examples: Kudzu, Brown Tree Snake,
Blue Water Hyacinth
**Be familiar with examples
of introduced species to
the US
(table 16.1 page 360)
Frogs…..
• Bioaccumulation
• Biomagnification
Facts to Know
• Species is considered extinct when it has not
been seen for at least 50 years or when the
last of a few monitored individuals die.
• endemic species: Found no where else on
earth
• range: The area in which a particular species is
found
Bioinformatics
• Organizing and storing useful biological
information about wild species using a data
base
• Provides computer tools to find, visualize,
analyze, and communicate biological
information
.
Biophilia
An inherent affinity for the natural world
(love of life)
Facts to Know
• Commercial extinction: Depletion of the
population of a wild species used as a
resource to a level at which it is no longer
profitable to harvest the species.
• Where is declining biological diversity the
greatest problem?
Florida, California, Hawaii Hawaii is #1
Facts to Know
Biodiversity Hotspots: Describes relatively small areas
of land that contain an exceptional number of endemic
species and are at high risk from human activities.
(Page 359 figure 16.8)
Human Causes of Species
Endangerment
Give three examples of:
– habitat destruction, habitat
fragmentation, or habitat degradation
–invasive species (biological pollution)
–pollution
–overexploitation
How Important is the Tropical
Rainforest?
• Cover 7% of the Earth’s surface but has as
many as 50% of the Earth’s species inhabit
them
Tropical Deforestation and Degradation
Primary causes
– Rapid population growth
– Poverty
– Exploitive government policies
– Exports to developed countries
– Failure to include ecological services in evaluating
forest resources
Tropical Deforestation and
Degradation
Secondary causes
– Roads
– Cattle ranching
– Logging
– Tree plantations
– Flooding from dams
– Unsustainable peasant farming
- Mining
- Cash crops
- Oil drilling
What Happens When
Tropical Rainforest Are Destroyed?
• Birds that migrate from North America to the
rain forest in Central America and the
Caribbean have been declining in numbers
faster than other migratory birds
• The forest itself generates much of the rainfall
in tropical rain forest. If half of the existing
rain forest in the Amazon region of South
America were to be destroyed, precipitation in
the remaining forest would decrease.
What Happens When
Tropical Rainforest Are Destroyed?
• As the land became drier, organisms adapted to moister
conditions would be replace by organisms able to tolerate the
drier conditions. Many endemic species would become
extinct.
• Disruption of the evolutionary process.
– Are Tropical Rainforest has supplied the base of ancestral
organism from which adaptive radiation occurs.
– Are eliminating nature’s ability to replace its species
through adaptive radiation?
Overfishing
• Tragedy of the commons???
• Commercial fishing methods
Bycatch
• Bycatch is the term used for the accidental capture of
non-target species in fishing gear. Humpback whale
entangled in a fishing net.
Bycatch
Conservation Biology
The scientific study of how humans impact
organism and the development of ways to
protect biological diversity.
Conservation Biology
• What are the concepts that guide it?
– Large habitats are more effective at safeguarding
species than several habitat fragments
– Large areas of habitat typically have the potential
to support greater species richness.
– It is better if areas of habitat for a given species
are located close together rather than far apart.
Conservation Biology
– Areas that are inaccessible to humans are better
than human accessible areas.
– It is more effective and more economical to
preserve intact ecosystems in which many species
live than to work on preserving individual species
one at a time.
– Higher priority is given to preserving areas that
are more biologically diverse than others.
(Remember the Hot Spots?)
Three Techniques of Conservation
Biology
1. Ecosystem Approach
• In situ conservation
– Protecting habitats
– Restoring damaged or destroyed habitats
– Preserve balanced populations of species in their
native habitat
– Establish legally protected wilderness areas and
wildlife reserves
– Eliminate or reduce the populations of nonative
species
Three Techniques of Conservation
Biology
2. Species Approach
• Identify endangered species and give them legal
protection
• Preserve and manage crucial habitats
• Ex situ conservation
– Zoos, aquariums, botanical gardens, seed banks
• Reintroducing endangered species to nature
Three Techniques of Conservation
Biology
3. Wildlife Management Approach
• Manages game species by:
– Using laws to regulate hunting
– Establishing harvest quotas
– Developing population management plans
– Using international treaties to protect migrating
game species such as waterfowl
Wildlife Refuges
• Teddy Roosevelt established Pelican Island off
Florida’s Atlantic coast as the 1st wildlife
refuge to protect the brown pelican (1903)
• Now have 508 refuges, 85% are in Alaska
• ¾ are wetlands for protection of migratory
waterfowl
Laws, Acts, and Organizations
•
•
•
•
•
CITIES
Lacey Act
Endangered Species Act
Wild Bird Conservation Act
Magnuson Fisheries Management and
Conservation Act
United States
• Lacey Act (1900)
– Prohibits transporting live or dead wild animals or
their parts across state borders without a federal
permit
• Endangered Species Act (1973)
– Endangered or threatened species cannot be
hunted, killed, collected or injured in the United
States
The Endangered Species Act
• There are over 1100 species on the list – 60% are
plants and 40 % are animals. Hawaii leads this list
(298+). Each year about 85 species are added to the
list
• Requires all commercial shipments of wildlife and
wildlife products enter or leave the country through
one of nine designated ports.
The Endangered Species Act
• National Marine Fisheries Services (NMFS) identifies
and list endangered and threatened ocean species.
• U.S. Fish and Wildlife Service (USFWS) identifies and
list all other endangered and threatened species.
• Adding or removing a species from the list must be
based on biology, not economic or political reasons
The Endangered Species Act
• Forbids federal agencies to carry out, fund, or
authorize projects that would either
jeopardize, destroy or modify the critical
habitat.
• Fines and jail sentences can be imposed on
private lands to ensure protection of the
habitats of endangered species.
Wild Bird Conservation Act
• Imposed a moratorium on importing rare bird
species
Magnuson Fisheries Management and
Conservation Act
• Gives the federal government authority to
manage fisheries in the zone between 3 and
200 miles off the U.S. shore. There is no limit
on the number of U.S. fishing vessels, but
quotas can be imposed on the quantity of fish
taken.
Other Solutions
• Biosphere Reserves
• Reintroduction of endangered species
– Restoration Ecology