Transcript Extinctions, Endangered Species, and Hope

The Biodiversity Crisis
Cenozoic
Era
Period
Millions of
years ago
Quaternary
Today
Bar width represents relative
number of living species
Extinction
Species and families
experiencing
mass extinction
Current extinction crisis
Tertiary
65
Extinction
Cretaceous
Mesozoic
Cretaceous
Jurassic
180
Extinction
Triassic
Triassic
250
Extinction
345
Extinction
Permian
Paleozoic
Carboniferous
Permian
Devonian
Devonian
Silurian
Ordovician
Cambrian
500
Extinction
Ordovician
Fig. 4-12, p. 93
The Biodiversity Crisis
Endangered & Threatened
Species
AT RISK
SPECIES
 Some species have
characteristics that
make them vulnerable
to ecological and
biological extinction.
Generalist and Specialist Species:
Broad and Narrow Niches
SPECIES GONE OR AT RISK
The International Union for the Conservation of
Nature and Natural Resources (IUCN) publishes
an annual Red List
They place species into 9 categories
The 2010 Red List contains 18,351 species at risk
for extinction out of 55,926 evaluated (33%).
SPECIES EXTINCTION
Species can become extinct:
Locally
Ecologically
Globally (biologically)
Global Extinction
Some animals have become
prematurely extinct because of human
activities.
Dodo
Steller’s sea cow
SPECIES AT RISK
 Percentage of various species types threatened with premature
extinction from human activities.
U.S. STATS
 Threatened species by broad taxonomic
grouping:
Mammals: 37
Birds: 74
Reptiles: 32
Amphibians: 56
Fishes: 177
Molluscs: 273
Other Invertebrates: 258
Plants: 245
U.S. FWS
Reasons for biodiversity loss
HIPPO
H:habitat destruction and degradation
 I: invasive species
P: population growth in humans
P: pollution
O: overexploitation
H: habitat degradation or loss
Terrestrial
 Deforestation
 Loss of grasslands
Aquatic and marine
 Benthic habitat loss
 Erosion
 Eutrophication
TROPICAL DEFORESTATION
Why Should We Care about
the Loss of Tropical Forests?
HABITAT LOSS, DEGRADATION, AND
FRAGMENTATION EXAMPLES
Commercial fishing
BEFORE
AFTER
I: invasive species
 Non-native species
 Not all exotics are invasive
Characteristics of invasives
 Not all exotic species are invasive.
 Many invasive species have
qualities that make them successful
in novel environments
© US FWS
Ecosystems that are vulnerable to invasives
Zebra mussel
~2 months
ecological & economic damage
Zebra mussel impacts
 Negative
Decreased
populations of native
shellfish
Altered water
chemistry
Disruption of trophic
dynamics
 Positive
Increased water
clarity
Increased light
penetration into
water column
Increased
photosynthesis
Increased
populations of some
other organisms
Lake Victoria
P: pollution
Terrestrial
 Acid deposition
 Superfund sites
 Litter
 Pesticides
 Inorganic fertilizers
 Tropospheric ozone
Aquatic and marine
 Cultural eutrophication
 Pollutant deposition and
leaching
 Litter
Pollutant Impacts: Litter
Pollutant Impacts: Nutrient loading
Peregrine Falcons:
a success story
Pollution
 Each year pesticides are estimated to kill:
Kill about 1/5th of the U.S. honeybee colonies.
67 million birds.
6 -14 million fish.
 And to threaten 1/5th of the U.S.’s endangered
and threatened species.
O: overexploitation
 Hunting
 Commercial fishing
Extinct: Passenger Pigeon
Figure 11-1
Reminders:
OVEREXPLOITATION
Figure 11-16
Whooping cranes:
a fledgling success story
Whooping Crane Cons. Assoc.
 Current Whooping Crane population:
 Wild #: 407 (99 pairs)
 Captive #: 167 (34 pairs)
Source: Whooping Crane Conservation
Association
P: human population growth
Purple loosestrife
1968
1978


reduces diversity
loss of food & nesting sites
for animals
Africanized Honeybee or Apis mellifera scutellata (lepeletier)
Alias: Africanized honeybee, Brazilian bees and killer bees
Introduced to new area:
-> In 1957 Warrick Kerr brought them to South America to help the Brasilian bee keeping industry that was failing.
The queens and worker Africanized Honeybees were released and aggressively began to breed with the native bees.
-> First came to Texas in 1990
Impacts:
-> They defend their nest from a 50 foot radius and has caused many deaths of pets, livestock, and people who could
not escape the chasing bee; hence the name “killer bee.”
->They are using up the resources in the rain forest, especially in Brasil.
-> They move to places with resources- have good colonial mobility and swarm a lot more compared to the European
honeybees (who hoard and survive through the winter with saved honey). They move very quickly! They use up
resources in one area and move on.
-> They compete with the A. Mellifera who is typically used in the commercial harvesting of honey. They kill the
queen bee and replace with their own; they mate with A. Mellifera.
Economically: people do not want to work with such aggressive bees, leading to a labor shortage and higher prices
to find workers
Ecosystem wise: the killer bee can out compete the native pollinators displacing the ecosystem
http://www.padil.gov.au/viewPestDiagnosticImages.aspx?id=370
www.bees-online.com/routeofafricanbees.gif
Hemlock Woolly Adelgid
(Adelges tsugae)
IntroductionArrived (1920s
west coast, 1950s
east coast)
accidentally in
shipments from
Asia.
Impact- Eastern Hemlock
and Carolina Hemlock
destruction. After infestation,
they defoliate prematurely
and can die if untreated.
Burmese Python (Python
Molurus Bivittatus)
Introduced by exotic pet trade
Threatens ecosystems by out-competing
native species, spreading disease, and
with predation
Invasive region: Southern Florida and Puerto Rico
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http://myfwc.com/images/Animals/BurmesePython_Origin.jpg
Wanted: Wild Boar
The Wild Boar is invasive to the Southeastern U.S.
The Wild Boar was unfortunately introduced
to the United States by Europeans as a
means for food. The Wild Boar is negatively
affecting the Southeastern United States,
the environment in which it was introduced.
It kills crops, and seriously damages native
plants by destroying their habitat through
wallowing, rooting for food, and selective
feeding. Also, wild boar are feral swine, so
they are at a high risk to spread rare, hardto-treat diseases like Swine Flu.
Comb jelly (Mnemiopsis leidyi)
 Invasive species in the Black
Sea
 Accidentally introduced via
ballest water in oil tankers
 It’s a major carnivorous
predator of zooplankton, as well
as meroplankton, pelagic fish
eggs and larvae
EUROPEAN GYPSY MOTH
“Lymantria Dispar”
Brought from Europe in the 1860’s.
Scientists studying larvae silk production
let insects accidentally escape.
All across New England, caterpillars strip
trees of their foliage so they can’t feed
themselves.
The tree dies off, also destroying a
habitat for other animals use for food
and shelter.
The species eats at a rate of 5 miles per
year.
Asian Long-horned Beetle
Introduced through wood packaging from Asia.
Larvae borrow into trees damaging vascular tissues.
Overtime, wood is weakened and the trees succomb to fungal
infections.