chapter 10 biodiversity
DESCRIPTION
Chapter 10 Biodiversity. 10.1 What is biodiversity? 10.2 Biodiversity at risk 10.3 The future of biodiversity. Biodiversity – the variety of living things in an area; Three levels of biodiversity: 1. Genetic diversity 2. Species diversity 3. Ecosystem diversity. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 10Biodiversity
10.1 What is biodiversity?10.2 Biodiversity at risk10.3 The future of biodiversity
Biodiversity – the variety of living things in an area;
Three levels of biodiversity:
1. Genetic diversity
2. Species diversity
3. Ecosystem diversity
When we talk about “biodiversity of the earth,” we usually mean species diversityGuess the number of species on the planet?Latest estimate: 8.7 million species
From Science Daily: “Furthermore, the study, published byPLoS Biology, says a staggering 86% of all species on land and 91% of those in the seas have yet to be discovered, described and catalogued.”
Benefits of Biodiversity
1. Biodiversity can affect the stability of ecosystems
When even one species is lost, it affects the entire ecosystem
Keystone species – species that are critical to the survival of an entire ecosystem
Example: sea otter
Benefits of Biodiversity
2. Healthy ecosystems provide good ecosystem services – the benefits that people obtain from ecosystems
Ecosystem Services: the benefits people obtain from ecosystems
RegulatingBenefits obtained from
regulation of ecosystem processes
• climate regulation• disease regulation
• flood regulation
ProvisioningGoods produced or provided
by ecosystems• food
• fresh water• fuel wood
• genetic resources
CulturalNon-material benefits from
ecosystems• spiritual
• recreational • aesthetic
• inspirational• educational
SupportingServices necessary for production of other ecosystem services
• Soil formation• Nutrient cycling
• Primary production
Benefits of Biodiversity3. Humans need biodiversity for medical, industrial, and
agricultural purposes(existing uses and genetic information for new uses)
Foxglove
Digitalis purpurea, EuropeDigitalis for heart failure
Pacific yewPacific NorthwestOvarian cancer
Potential new food crops may be lost forever
Source: FAO
4. Ethics, aesthetics, and recreationE.O. Wilson: there is “spiritual, religious and
psychological value” in preserving biodiversity
Ecotourism – tourism that supports conservation and sustainable development of ecologically unique areas
Extinction – three types:Local – species is extinct in one area, but
still found in other locationsEcological – so few left that it no longer
plays its ecological role in the communities in which it is found
Biological extinction – completely gone from the planet
Biodiversity at Risk
Extinction is a natural process
• Extinction is irreversible: once a species is lost, it is lost forever
• 99.9% of all species that ever existed are now extinct
Earth has had five mass extinctions so far
Background extinction rate •“normal” rate of extinction that occurs naturally • background extinctions are usually unrelated • for example one estimate gives the background extinction rate for birds as 1 species lost per 400 yearsMass extinction events • when 50-95% of all species go extinct in a relatively short period of time• five events in Earth’s history have killed off massive numbers of species at once
Mass extinctions
• Biggest: end of Permian (250mya), loss of 95% of species• Most recent: K-T event at end of Cretaceous (65mya), asteroid struck
earth, led to extinction of dinosaurs
Extinction rates
Humans profoundly affect rates of extinction (causing 100 to 1000 extinctions per million species instead of the background extinction rate of 1-5 species per million)
Estimated annual extinction rate before humans: 0.0001%
Estimated annual extinction rate since humans: 0.1-1%
Scientists think that we are in the 6th mass extinction and this time, it is due to human activity
Passenger pigeon
Great auk Dodo Dusky seaside sparrow
Aepyornis(Madagascar)
Extinct species – due to human activities
Think about this…
Name some characteristics of species that make them especially likely to go extinct:
List is on the next slide….
Characteristic ExamplesLow reproductive rate(K-strategist)
Specialized niche
Narrow distribution
Feeds at high trophic level
Fixed migratory patterns
Rare
Commercially valuable
Large territories
Blue whale, giant panda,rhinoceros
Blue whale, giant panda,Everglades kite
Many island species,elephant seal, desert pupfish
Bengal tiger, bald eagle,grizzly bear
Blue whale, whooping crane,sea turtles
Many island species,African violet, some orchids
Snow leopard, tiger, elephant, rhinoceros, rare plants and birds
California condor, grizzly bear, Florida panther
These are characteristics that increase the risk of extinction, along with examples of each
How do humans cause extinction?HIPPCO
1. Habitat destruction – may be complete destruction or habitat fragmentationHabitat destruction is the number one threat to
biodiversity
How do humans cause extinction?HIPPCO
2. Introduction of invasive speciesExample: Mites, called Verroa destructor,
introduced from Asia have seriously reduced the wild honeybee population in the U.S.
1918
2000
Spread of fire ants
Kudzu• Fast-growing climbing
vine from Asia• Introduced to control
erosion
European Starling• Released into New York
City in the late1800’s by a man who wanted to introduce to the U.S. all of the birds mentioned in Shakespeare
• Now widespread across North America
• Outcompetes many native birds, such as bluebirds, for nest holes
How do humans cause extinction?HIPPCO
3. Population growth – root of the problem?
Food for thought: What native species could live in these conditions?
How do humans cause extinction?HIPPCO
4. PollutionExample: Use of DDT
almost caused the extinction of the Bald Eagle and other predatory birds
Biomagnification
Also called biological magnificationAccumulation of pollutants in higher order trophic
levels
How do humans cause extinction?HIPPCO
5. Climate change polar bear – loss of sea ice bleaching of coral reefs
• Golden toads were discovered in 1964, in Monteverde, Costa Rica
• The mountainous cloud forest has a perfect climate for amphibians
• Extreme sexual dimorphism• Unfortunately, they became
extinct within 25 years • Causes: 1. Changes in habitat – drying of cloud
forest due to global warming, ENSO2. Narrow window of time for
reproduction – breed in temporary ponds which dried up early
3. Limited range4. Disease Female
Males
How do humans cause extinction?HIPPCO
6. Overharvesting, hunting, poachingBoth legal and illegal collecting of organisms
has had a negative impact
Areas of Critical Biodiversity
Biodiversity “hotspots”1. High numbers of endemic species – means
many organisms that live there are not found anywhere else in the world
2. Threatened by human activities
•Tropical rainforests•Coral reefs and coastal ecosystems•Islands
Global Biodiversity Hotspots
Concentration of rare species
Low Moderate High
Top Six Hot Spots
1 Hawaii2 San Francisco Bay area3 Southern Appalachians4 Death Valley5 Southern California6 Florida Panhandle
4
5
2
6
3
1
U.S. Biodiversity Hotspots
Efforts to Preserve Biodiversity1. Efforts to save
individual species
• Captive-breeding programs – California condor population went from 9 in 1986 to 58 in 2002
• Zoos, aquariums, parks, gardens – for many, there is now more emphasis on preservation and less on entertainment
• Gene banks and seed banks
Efforts to Preserve Biodiversity2. Efforts to save habitats and ecosystems - more
effective to save biodiversity this way (rather than focusing on one species); It is important to save the entire ecosystem, not just an isolated species
Example: Vermillion Darter
The vermilion darter is found only in the Turkey Creek drainage, a tributary of the Locust Fork of the Black Warrior River, Jefferson County, Alabama.
Efforts to Preserve BiodiversityIn Alabama, Forever Wild Land Trust acquires land that will be used for wildlife management areas, nature reserves, state parks and recreational areasProvides areas of habitat for many species
Efforts to Preserve Biodiversity3. Legal protection – exists in many countriesU.S. has Endangered Species Act (ESA), passed in 1973Main Provisions:• U.S. Fish and Wildlife Service (USFWS) compiles a list of
endangered and threatened species on land and in freshwater, National Marine Fisheries Service (NMFS) is responsible for marine species
• End./Thr. Species may not be killed, caught, sold (penalties include fines and jail, enforced mainly by USFWS, also Coast Guard)
• Fed. Govt. may not carry out projects that jeopardize listed species
• Dept. of Interior should designate and protect critical habitat necessary for survival of listed species
• USFWS must develop a recovery plan for each listed species
ESA terminologyEndangered species – a species that is likely to become extinct
unless some protective measures are enacted immediatelyThreatened species – species with declining populations, likely to
become endangered if not protectedCritical habitat – areas that are critical to the conservation of the
species, may be where it lives or where it migratesAlabama endangered species:
Green pitcher plant
Watercress darter
Gopher tortoise
Gray bat
Green sea turtle
Red-cockaded woodpecker
Successful recoveries• Species which increased in population size since being placed on the endangered list
include:• Bald Eagle (increased from 417 to 11,040 pairs between 1963 and 2007); removed
from list 2007 • Whooping Crane (increased from 54 to 436 birds between 1967 and 2003) • Kirtland's Warbler (increased from 210 to 1,415 pairs between 1971 and 2005) • Peregrine Falcon (increased from 324 to 1,700 pairs between 1975 and 2000);
removed from list • Gray Wolf (populations increased dramatically in the Northern Rockies, Southwest,
and Great Lakes) • Gray Whale (increased from 13,095 to 26,635 whales between 1968 and 1998);
removed from list • Grizzly bear (increased from about 271 to over 580 bears in the Yellowstone area
between 1975 and 2005); removed from list 3/22/07 • California’s Southern Sea Otter (increased from 1,789 in 1976 to 2,735 in 2005) • San Clemente Indian Paintbrush (increased from 500 plants in 1979 to more than
3,500 in 1997) • Red Wolf (increased from 17 in 1980 to 257 in 2003) • Florida's Key Deer (increased from 200 in 1971 to 750 in 2001) • Hawaiian Goose (increased from 400 birds in 1980 to 1,275 in 2003) • (increased from 3,500 in 1979 to 18,442 in 2004)
Controversy over ESA
• How successful has it been?• Does it trample individual rights by
prohibiting certain uses of critical habitat owned by private citizens (limits on logging, mining, development, etc.)?
• Does it hinder economic development by such prohibitions?
Efforts to Preserve Biodiversity4. International effortsIUCN – International Union for the Conservation of
Nature and Natural Resources; organization that publishes the “red list” of endangered species, promotes preservation of species and habitats (http://www.iucnredlist.org/)
CITES treaty – first effort to stop killing of African elephants for ivory tusks, prohibits trade of many species
Efforts to Preserve Biodiversity5. Private organizationsExamples: World Wildlife Fund, Nature Conservancy,
Greenpeace InternationalFreshwater Land Trust– in Alabama, buys land to enhance
water quality and preserve natural areas