Transcript Biological Diversity

This presentation is
drawn from an
International Union
for the Conservation
of Nature’s 1996
Species Survival
Commission Study,
and also from. . . .
The WR 2000-2001
report, produced by the
World Resources
Institute, the United
Nations Development
Programme (UNDP),
the UN Environment
Programme (UNEP),
and the World Bank,
with over 175 scientists
contributing
Biological Diversity
The Variety of Species and the
Genetic Diversity within them: the
Key to the Vitality of Life
Relative
Abundance
of Species
Biodiversity Decline An Overview
Biodiversity Loss -- Greatest
Environmental Threat?

Nearly 400 biologists in a recent poll
think so.
– Seven of 10 said they believed a
"mass extinction" was already
underway
– An equal number fear that up to
one-fifth of all living species
could disappear within 30 years.
Mammals
 25%
of all the world's wild
mammals are threatened with
extinction
–Habitat loss and degradation are
primarily responsible.
African Elephants
Primates
Closest cousins to humans (chimps,
e.g., 98.5% of same dna)
 325 species, of these, 130 endangered,
including all Orangutans,
chimpanzees, and most gorillas.

– with subspecies included, 608 distinct
populations
Gorillas and Chimpanzees
“critically endangered” (Nature, 2003)

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Due to hunting + now ebola.
Popluations plumitted by ½ in Gabon
and Republic of Congo between
1983+2000; these 2 countries have
80% of world’s gorillas and most of its
chimps.
rate of extermination is increasing.
Princeton’s Walsh: “If we don’t do something radical,
gorillas and chimpanzees will be effectively extinct from
western equatorial Africa within the next ten years.”
Miss Waldron's red colobus ~ disappeared in 20th
century, declared extinct September 2000
Golden Bamboo Leumr
(Madagascar)
Sumatran
orangutan
(Indonesia)
Cross River Gorilla
(Nigeria and Cameroon,
West Africa; about 150 remain in
small, isolated populations)
Yellow-tailed woolly monkey
(Andes,Peru)
Plants
1
in 8 plant species is
threatened with extinction.

In the United States it is 1 in 3.

– 90% of plants on endangered list are native
only to the U.S.
Main causes:
– habitat loss due to agriculture, logging,
development and
– exotic species invasions drive out native species
Semaphore Cactus
Trees
Logging and conversion have shrunk the
world’s forests by as much as half.
 9 percent of the world’s tree species are
at risk of extinction


World Resources 2000-2001: People and
Ecosystems: The Fraying Web of Life, sept 2000
Dembaya
rodriguesiana
Extinct in the wild.
This species is
unique to Rodrigues
Island and once
included male and
female trees. The one
remaining female
tree was blown down
in a cyclone in 1984.
The male, pictured
here, died in 1994.
Cuttings of both
these trees have been
taken.
Hyophorbe
amariculls
One remaining in the
wild. This palm is
the only known plant
of its species, which
is unique to the
island of Mauritius.
Although it produces
both male and
female flowers, no
viable fruit has been
produced, and efforts
to grow it in the
laboratory have
failed.
Buckeye
Tree - Old
Growth Eastern
United
States
Plant diversity declining ~
fewer seed varieties cultivated



In the USA:
– 80% fewer seed varieties sold, compared to a
century ago.
– 29% of plant species (4,669) endangered
Globally
– 30,000 plant species endangered
Genetic losses permanent
– A pest-resistant gene found in a seed from Turkey was
nearly extinct.

Worldwatch, 1999
Reptiles

Jamaican
Iguana,
thought
extinct,
numbers
about 100
animals
Birds
25%

already extinct
Birds are probably suffering the greatest
declines currently

Vitousek, P. M., J. L. Mooney, and J. M. Melillo. July 25,
1997. Human Domination of Ecosystems. Science
277(5325): 494-9
Dusky Seaside Sparrow
Extinct
California Condor
- A huge vulture that declined from habitat loss and hunting until the few remaining birds were captured.
Now there are a few dozen of the birds in Arizona and California.
- Millions of dollars have been spent in an effort to bring them back from the brink of extinction. Some
captive bred birds were reintroduced to the wild.
- But in 2000 the reintroduction broke into disarray, as most of the reintroduced birds were re-captured
due to high mortality rates. (They kept eating animals with lead shot in their bodies, or consuming other
human-produced poisons, such as radiator fluid). Long-term survival of these birds is doubtful.
Spotted Owl &
Habitat
Green
KingFisher
Willow FlyCatcher
Wilson’s
Warbler
SW United States
Endangered Marine Life
Green Sea Turtle
Manatees
Andronomous Fish declining, e.g.,
Pacific Salmon is extinct from
much of its original range
Yet, Summer 2000:
The Clinton administration refused to
breach a series of dams in the upper
Columbia River basin, even though
government scientists concluded
breaching was the best hope for wild
salmon.
Atlantic Salmon also declining

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The most critical
breeding-age fish
estimated at 2.5-5
million (originally)
800,000 (1975)
80,000 (1998)
Cross-breeding with less
hearty domesticated
salmon is suspected
Endangered Freshwater
Ecosystems & Organisms
Dams, Channels and water
diversions largely responsible

They have
fragmented nearly
60 percent of the
world’s largest
rivers, seriously
degrading them.

World Resources
2000-2001
 Twenty
percent of the
world’s freshwater
species are extinct or
in peril
 At least 10,000
freshwater fish
species are threatened
globally.
Dam devastation
In 1950: 5,270
large dams
 Today: there are
36,500 large
dams

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
Since Egypt's Aswan
Dam completed in 1970,
number of fish species
harvested on the Nile has
dropped by two thirds
Salmon are extinct in
much of the United
States due to dam
building, and are widely
imperiled elsewhere
Channeling Death
 Channelized
waterways in
1900 = almost 9,000
 Today = nearly 500,000
 Result: extinction of many
species and dramatic declines
in many others.
Other insults threatening
freshwater ecosystems
Industrial discharges and agricultural and
urban runoff
 Competition from nonnative species
displace and drives native fish toward
extinction.
 Overfishing,

– e.g., is currently driving various sturgeon
species toward extinction in the Caspian
Sea and its tributaries.

Is the Lake Winnebago Sturgeon next?
Yet more insults
 Water
diversions
– for agriculture and urban water supplies >> all
native fish species in the lower Colorado River
basin are either endangered or extinct
 Siltation
– a major factor in the decline of endemic fishes
globally
 Wetland
conversion
– Half of the world’s wetlands destroyed in the
last century.

World Resources 2000-2001
Amphibian - Decline
 Frogs,
toads, and salamanders
going extinct and declining
rapidly
 Primary cause: Destruction of
wetlands.
Declines are also occurring in
apparently undisturbed habitats
(1)
(2)
(3)
Gastric brooding frogs (2 species), native
to Australia, disappeared in the early
1980s.
The red-legged frog is no longer present in
entire counties and valleys on the North
American Pacific coast, where it was once
abundant and common.
The golden toad of Costa Rica was last
seen in 1989.
Golden Toads
Costa Rica (picture taken in 1989)
Amphibian - Deformities
Since 1995, reports of malformed
amphibians have increased. Suspects:
 skin
funguses kill larvae and adult
amphibians.
 Non-native
predators, such as
voracious bullfrogs and trout, that kill
native amphibian species.
Amphibian - Deformities
EPA 2003: ‘Smoking Gun’ study finds
atrazine, a common pesticide, responsible
for sexual abnormalities in frogs (producing
company’s scientists dispute the conclusions; and lead
scientist resigned, complaining they tried to prevent the
dissemination of the findings; a UF professor was
implicated by the NY Times in the suppression effort.
Atrazine is banned in 7 European, but not in
North America.

Other pollutants, including herbicides, insecticides and
crop fertilizers remain suspects too.
Biodiversity Loss is also about
declining genetic variety
• Declining numbers fosters genetic
“bottlenecks” which reduce genetic
variety.
• Reduced genetic variety increases the
vulnerability of species to disease by
eliminating genetically resistant
members.
The bottleneck
effect
Main threats to Species
Habitat destruction by logging and
mining, for agricultural or human
settlements and transportation
 Invasive Species introductions
– Which eat or compete
against/displace native species
– Which reduce or eliminate food
sources for native species

Endangered
Ecosystem Types
Not only species are at risk
-So are entire ecosystems
North America’s Ecosystems
Of North America’s 116 large Ecoregions
 13
have biodiversity as great as in
the Everglades
 32 are rated “globally outstanding”
 BUT
30 have shrunk 98% and are
“critically endangered.”

Source: "A Conservation Assessment of the Terrestrial Ecoregions of North
America”, World Wildlife Fund
Endangered ecoregions

Midwest’s tallgrass prairies and oak savannas
– have been almost entirely destroyed

Southeastern pine forests (N. Florida)
– Once supported one of the richest assemblages of forest-floor plants
on earth, as well as now-endangered animals such as the red
cockaded woodpecker and gopher tortoise.
– Merely 2 percent of these forests remain

Southern California Sage Scrub Ecosystems
– These ecosystems, largely destroyed by intensive development,
represent one of only five habitat groups on earth with
“Mediterranean” climates.
– Although these five habitat groups occupy only fragments of earth's
surface, these unique habitats -- hot and dry in summer, cool and
wet in winter -- they retain 20 percent of earth’s plant species!
Endangered and Threatened
Species in Florida
Atlantic Loggerhead
American Alligator
Hawksbill
Atlantic Green
American Crocodile
Florida
Panther
West Indian Manatee
Florida
Black Bear
Key Deer
Red-Cockaded
Woodpecker
Snail
Kite
Peregrine Falcon
Bald
Eagle
Crested Caracara
Wood Stork
Florida
Scrub Jay
10 Million Years: period
needed for recovery from
extinction episodes
• Whether episode is massive or minor
• We may have already, or soon will
have, destroyed enough species that
recovery will require millions of years.
• 10 million years is 20 times longer than
we (Homo sapiens) have existed and
longer than our species may persist.
• From March 2000 study in Nature