chapter 11 biodiversity - sewanhaka high school...human-caused losses in biodiversity • acronym...
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Chapter 11
Biodiversity
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OUTLINE
• Biodiversity and the Species Concept
Varied Definitions
• Benefits of Biodiversity
• Threats to Biodiversity
Natural and Human-Caused Reductions
• Endangered Species Management
ESA
CITES
• Captive Breeding
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BIODIVERSITY OF THE SPECIES CONCEPT
• WHAT IS BIODIVERSITY?
GENETIC DIVERSITY - measures the variety
of different versions of the same genes within
a species (gene pool)
SPECIES DIVERSITY - measures the number
of different kinds of organisms within a
community
ECOLOGICAL DIVERSITY - measures the
richness and complexity of a community
(food web complexity/levels/niches)
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WHAT IS BIODIVERSITY?
• SPECIES DIVERSITY
SPECIES RICHNESS - total number of
species in a community
SPECIES EVENNESS -relative abundance of
individuals within each species
Community A Community B
*10 species * 10 species
*8-10 of each species * 2-10 of each species
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WHAT ARE SPECIES?
• Definitions of Species (3)
1. REPRODUCTIVE ISOLATION - a.k.a....
BIOLOGICAL SPECIES CONCEPT
organisms that can breed in nature and
produce fertile offspring are a “species”
ie: Horses & Donkeys and Lions & Tigers, can
produce offspring (Mules and Ligers) BUT
they are sterile, therefore, Horses & Donkeys
and Lions & Tigers are different species.
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WHAT ARE SPECIES?
Definitions of Species (3)
2. PHYLOGENETIC SPECIES CONCEPT - emphasizes the cladistic relationships (branches on a taxonomic tree)
defines a species as the smallest group of individuals on a phylogenetic tree
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WHAT ARE SPECIES?
• Definitions of Species
3. EVOLUTIONARY SPECIES CONCEPT - defines species in terms of evolutionary
history based on genetic information.
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MOLECULAR TECHNIQUES
• DNA sequencing and other molecular
techniques give insight into taxonomic and
evolutionary relationships.
GENOME - total DNA sequence that
characterizes a species
Species classification or even identification
of an individual can be done from samples
such as blood, fur, or feces.
Genome information is crucial in breeding
facilities to increase diversity around the
world.
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HOW MANY SPECIES ARE THERE?
• Currently 1.5 million species identified
• Estimates range between 3-50 million
Recent data support an estimate of 4 to 6 million insect species alone.
Invertebrates make up ~70% of all known species, and probably most of those still to be discovered. Most are found in the tropics.
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BIODIVERSITY HOTSPOTS
• Tropical rainforests and coral reefs are biodiversity hotspots.
34 hotspots (1.4% of world’s land area)
75% of the world’s most threatened mammals, birds and amphibians.
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BIODIVERSITY HOTSPOTS • Hot spots are at significant risk due to human
disruption and potential loss of biodiversity
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BENEFITS OF BIODIVERSITY
• FOOD
Wild plants could provide new sources of food
or more genetic diversity for existing crops.
• DRUGS AND MEDICINES
More than 50% of all prescriptions contain
some natural product.
Pharmaceutical companies actively prospect
tropical countries for products.
Resources often extracted without
compensation (BIOPIRACY).
Sharing profits provides an incentive to local
people to preserve native species.
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BENEFITS OF BIODIVERSITY
• ECOLOGICAL BENEFITS
Soil formation
Waste disposal
Air and Water purification
Solar energy absorption and conversion
Biogeochemical and Hydrological cycles all
depend on biodiversity.
DIVERSITY CREATES STABILITY
We do not fully understand biological
communities. Loss of a seemingly
insignificant species can be damaging.
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BENEFITS OF BIODIVERSITY
• AESTHETIC AND CULTURAL BENEFITS
Hunting, fishing, camping, hiking, etc.
USFWS estimates Americans spend $104 billion annually on wildlife-related recreation.
Ecotourism can be an important form of sustainable economic development. Especially in developing nations.
Existence (intrinsic) value - organisms have value in and of themselves.
15
THREATS TO BIODIVERSITY
• EXTINCTION – the elimination of a species
NATURAL CAUSES
- In undisturbed ecosystems, background
rate appears to be one species per decade.
In this century, human impacts have
accelerated that rate, causing perhaps
hundreds to thousands of extinctions
annually.
(we don’t know for sure because we
haven’t discovered all species yet)
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NATURAL EXTINCTION
• Fossil record suggests more than 99% of all species ever in existence are now extinct.
• Periodically, the Earth has experienced mass extinctions.
ORDOCICIAN - 444 mya
- 85% of species died out
DEVONIAN - 370 mya
- 83% of species died out
PERMIAN PERIOD - 250 mya
- 95% of marine species and nearly half of all plant and animal families died out
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NATURAL EXTINCTION
END OF TRIASSIC - 210 mya
- 80% of species died out
END OF CRETACEOUS - 65 mya
- Dinosaurs and 50% of existing genera disappeared. 76% total
QUARTERNARY – PRESENT DAY
- 33-66% of species have or are dying out
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ACCELERATING EXTINCTION RATES
• Humans are accelerating the natural extinction
rates by 100 to 1000x.
If present trends continue, between 22% and
47% of all plants species will become extinct
within 50 years. Animals dependent upon
them would also go extinct.
This is equivalent to other mass extinctions
like the Cretaceous extinction.
THIS IS THE FIRST TIME IN HISTORY THAT
ONE SPECIES IS CAUSING THE EXTINCTION
OF ANOTHER
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HUMAN-CAUSED LOSSES IN BIODIVERSITY
• Acronym HIPPO summarizes the issues:
1. Habitat destruction
2. Invasive species
3. Pollution
4. Population (human)
5. Overharvesting
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1. HABITAT DESTRUCTION
• HABITAT DESTRUCTION – 50% of End.Spe.
Biggest reason for current increase in extinction is habitat loss
- Conversion of forest & grasslands to farmland, pastures, cities, etc.
Only 1/5 of remaining forest is old growth.
- Loss of habitat due to mining, dams, destructive fishing practices
- Habitat is fragmented into small, scattered plots due to roads, development
- Draining of wetlands, flooding from dams
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• INVASIVE SPECIES
Invasive (exotic) organisms thrive in new
territory where they are free of usual
predators, diseases, or resource limitations
that limited them in original habitat.
- Over past 300 years, approximately 50,000
non-native species have become
introduced into the U.S.
At least 4,500 are free-living.
15% cause environmental and/or
economic damage.
2. INVASIVE SPECIES
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2. INVASIVE SPECIES
• EXAMPLES OF INVASIVE SPECies
Kudzu vine – introduced as ornamental from
Japan, covering the south east
Purple loosestrife – introduced as ornamental
from Europe, displaces native vegetation
Zebra mussels – introduced in ballast water
to the Great Lakes, outcompeting natives for
food, economic damage to powerplants
• ISLAND’S ARE PARTICULARLY SUSCEPTIBLE
generally high in coevolution between
species, and lack of predation
ie: New Zealand, Galapagos, Madagascar
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2. INVASIVE SPECIES
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METHODS TO CONTROL INVASIVES
ERADICATION METHODS – removal of
individuals, usually time consuming and
expensive
- Biological Controls – introduction of
predators or parasites (a slippery slope!)
- Mechanical Controls – physically removing
individuals
- Ecological Controls – ie: using fire to kill
off non-native plant species (natives would
survive as they are adapted to fire),
draining lakes to kill off invasives
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3. POLLUTION
• POLLUTION
PESTICIDES – kill off target pests and many
other species, and bioaccumulate/magnify
PLASTICS – don’t decompose, they photo-
degrade with UV light over many years
CHEMICAL CONTAMINATION
- Lead, Mercury, PCB’s also can
bioaccumulate/magnify – leading to
disease processes
Effects of Global Warming on ecosystems
Effects of Acid Rain
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BIOACCUMULATION vs BIOMAGNIFICATION
• BIOACCUMULATION - Contaminants increase
in concentration in individual organisms
• BIOMAGNIFICATION - Contaminants increase in
concentration in the food chain
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4. HUMAN POPULATION
• HUMAN POPULATION
Human population growth and resource use.
~1804 = 1 billion people.
2016 = 7+ billion people.
2050 some estimate we will reach 10 billion.
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5. OVERHARVESTING
• OVERHARVESTING / OVERHUNTING
COMMERCIAL FISHING - All major fish
stocks are expected to collapse within 50
years (tuna, sharks, codfish, pollock, salmon)
BUSHMEAT TRADE – wild animals being
killed for food – subsistence and/or
commercially
PET TRADE – fish, birds, reptiles, wild cats,
primates – ~ 80% do not survive capture and
transport to destination
BLACK MARKET – animal parts sold illegally
(tusks, horns, skins, teeth) – many are used
in Traditional Chinese Medicines
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5. OVERHARVESTING
• Commercial Products and Live Specimens
Wildlife smuggling is very profitable.
- Fur, horns, live specimens, folk medicine
- Leopard fur coat = $100,000
- Mature cactus = $1,000
- 5 million wild birds sold worldwide each year an additional 3 million are caught but die before reaching market
128 million tropical fish sold annually in U.S.
- Cyanide released above coral reefs to stun fish. A single diver can kill all life on 200 sq. meters of coral reef in one day.
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5. OVERHARVESTING
Pet trade
80% of
wild
animals
die before
being sold
Cyanide
fishing is
killing reefs in
the
Philippines
and Indonesia.
Bush meat
more than
1 million tons
of wild animals
are sold for
human food
annually.
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5. OVERHARVESTING
• HUNTING AND FISHING LAWS
By 1890’s, most states had enacted some hunting and fishing laws.
- General idea was pragmatic, not aesthetic or moral preservation.
- In general, regulations have been extremely successful.
White tailed deer
Wild turkey
Snowy egret
American alligator
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CLASSIFYING ENDANGERED SPECIES
VULNERABLE are those that are naturally
rare or have been locally depleted to a level
that puts them at risk.
THREATENED are those likely to become
endangered, at least locally, in the near
future.
ENDANGERED are those considered in
imminent danger of extinction.
EXTINCT IN THE WILD are those which only
exist in captivity (zoos, breeding facility)
EXTINCT are those with no surviving
individuals
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ENDANGERED SPECIES ACT - 1973
• ESA regulates a wide range of activities involving endangered species:
Taking (harassing, harming, pursuing, hunting, shooting, killing, capturing, or collecting) either accidentally, or on purpose
Selling
Importing into or Exporting out of the U.S.
Possessing
Transporting or Shipping
• Prohibitions apply to whole organisms, body parts, and products made from the organisms.
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ENDANGERED SPECIES ACT
• Currently, U.S. has ~ 1,300 species on its Endangered and Threatened lists, and about 400 candidate species waiting for approval.
Numbers reflects more about human interests than actual status
- Invertebrates make up 75% of all species, but only 9% of T/E list.
Listing process is extremely slow; at least 18 species have gone extinct since being nominated for protection.
$150 million per year. Mostly for species of human interest or environmental need
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OTHER IMPORTANT LAWS TO KNOW!!
• LACEY ACT – 1900 - 1st Federal US law that required permits for transporting wildlife across state lines. Each State had their own wildlife laws that weren’t always the same.
• MAGNUSON-STEVENS FISHERY CONSERVATION AND MANAGEMENT ACT – (SUSTAINABLE FISHERIES ACT) – 1996 – manages fisheries from 9-200 nautical miles off the coast. Impose limits in this area.
• MARINE MAMMAL PROTECTION ACT – 1972
Protects all marine mammals in US waters
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OTHER IMPORTANT LAWS TO KNOW!! • CITES – 1975 – Convention on International
trade in Endangered Species of Wild Flora and Fauna – Controls trade of individual species.
Appendix I – endangered – trade is prohibited
Appendix II – threatened – trade is limited
Appendix III – protections vary by country
• UNESCO – United Nations Educational, Scientific and Cultural Organization - developed idea of BIOSPHERE RESERVES – protected areas that limit human impact to protect biodiversity. 600+ exist in the world.
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“SPECIAL” SPECIES
• Some endangered species merit special attention.
KEYSTONE SPECIES - species has major effect
on other members of community (wolf)
INDICATOR SPECIES - tied to specific
communities or successional stages (tadpole)
UMBRELLA SPECIES - require large blocks of
undisturbed habitat (spotted owl)
FLAGSHIP SPECIES - attractive organisms to
which people react emotionally (panda)
• Notable successes include bald eagle, alligator,
whooping crane
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RECOVERY PLANS
• Once a species is listed as endangered, the USFWS is required to propose a recovery plan detailing the rebuilding of the individual species to sustainable levels.
Takes many years, is expensive, and is subject to political interference
Once a species is endangered, much of its habitat and ability to survive is already often compromised.
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RECOVERY PLANS
• Opponents have continually tried to require economic costs and benefits be incorporated into planning.
In 1978, construction of Tellico Dam in Tennessee threatened a fish called the snail darter. A federal committee was given the power to override the ESA for economic reasons.
Sometimes economic interests are in conflict. Commercial and sport fishing for salmon in Columbia River is worth 1 billion per year, but farmers and electric utilities want the dams that provide irrigation and hydroelectric power.
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PRIVATE LAND AND CRITICAL HABITAT
• 80% of habitat for more than half of all listed
species is on non-public property.
Supreme Court has ruled destroying habitat
equates to “taking”.
- USFWS has been negotiating Habitat
Conservation Plans (HCP) with private
landowners.
Landowners allowed to harvest
resources or build on part of land as
long as endangered species benefits
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REAUTHORIZING ESA
• Endangered Species Act officially expired in 1992.
• Farmers, loggers, miners, ranchers, developers have tried to prevent its reauthorization.
• Scientists think we should focus on continent-wide preservation of ecosystems that support maximum biodiversity rather than individual species.
• Gap analysis - seeks out unprotected landscapes rich in species – to protect multiple species at once.
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GAP ANALYSIS
a holistic approach to
managing ecosystems
and species.
• J. Michael Scott –
Conservation biologist
• This biodiversity map
of the island of Hawaii
shows areas of high
species richness that
are not protected in
any preserve and
preserves that have
scenic and
recreational value, but
little in the way of
species protection.
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HABITAT PROTECTION
• R.E. Grumbine (conservation biologist)
suggests 4 principles:
Protect enough habitat for all native species
in a given region
Manage at regional scale large enough to
accommodate natural disturbances
Plan over a period of centuries
Allow for human use at a level that does not
result in significant ecological degradation
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SPECIES SURVIVAL PLANS
• CAPTIVE BREEDING PROGRAMS in zoos & botanical gardens are one method of saving threatened species.
Repositories of genetic diversity
- Most mammals in North American zoos are now produced from captive-breeding programs.
Reintroduction programs
But many species do not reproduce in captivity, and there are not enough zoos to maintain every species.
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SPECIES SURVIVAL PLANS
• CAPTIVE BREEDING PROGRAMS in zoos & botanical gardens are one method of saving threatened species.
ARTIFICIAL INSEMINATION (sperm from one male can be used in several females)
CROSS INCUBATION (eggs laid by one bird are hatched by another)
EMBRYO TRANSFER (embryos are implanted into other females to be raised)
ARTIFICIAL INCUBATION (wild eggs are collected and young released soon after hatching)
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SPECIES RESTORED BY CAPTIVE BREEDING
Nene Goose
California
Condor
Arabian Oryx Black-footed
Ferret
Golden-lion
Tamarin
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SPECIES SURVIVAL PLANS
• Zoos/gardens have limited space
How many can/should we save? Should we
preserve pathogens? Parasites?
Continued inbreeding of zoo specimens may
lead to fertility and infant survival problems.
Natural habitat may disappear while we are
busy conserving the species itself.
• Another alternative is to attempt to save species
in the wild by saving large parcels of land.
Provide funding for protection in native
habitats
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SPECIES SURVIVAL PLANS
• THERE MUST ALWAYS BE A BALANCE
BETWEEN WILDLIFE AND HUMAN LIFE.
• TRADEOFFS EXIST TO SAVE A SPECIES
Monetary costs to save the species
Economic losses if industry is affected
Public desire to save or not to save a species
Indigenous/Cultural uses must be considered
Ecotourism can benefit both wildlife and the
indigenous people of an area through economic
gains that would be lost without the wildlife.
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