Ecology

1
Ecology

• Chapters 3 through 6
• See board for homework and test schedule

2

• MEGAFAUNA

• The Wooly Mammoth
• The Sabertooth Cat

3
What caused the extinctions of the megafauna?

• Anthropogenic - Scientists use this word to
  distinguish changes that people have introduced
  to the environment from processes which are
  natural.
• Extirpated - a species that no longer exists in
  the wild in a certain place, but exists
  elsewhere.
• Endangered - a species when it is not Critically
  Endangered but is facing a very high risk of
  extinction in the wild in the near future.
• Extinct - a species that no longer exists, when
  there is no reasonable doubt that the last
  individual has died.

4

• Overkill hypothesis?
• Climate change?
• Something else?

5
Keystone Species

• Saving Species Preserves Ecosystems

6
The Dodo Bird
7
What is a Keystone Species?

• A keystone is the center stone in a stone
  archway without it the archway collapses.
• Some species are so important to the functioning
  of an ecosystem that they are called keystone
  species

8

• The starfish Pisaster ochracues is the pillar of
  the community on the exposed rocky shores between
  low and high tide. It is upon this organism that
  the stability of the entire system depends.
• Univ. of Washington Office of Research.
  Pathbreakers - Published November 1996

9
Niches and Biodiversity
10
Elephants as Keepers of the Savannah
11
Fig Tree
The Fig Tree

• The prophet Micha proclaims in his vision of
  peace in the Land "Each man will sit beneath his
  grapevine and his fig tree, and no one will fear.
  . . ."

12
Pacific Sea Otters
13
American Alligators
14
Prairie Dogs as Prairie Restorationists

• Prey base
• Habitat creation
• Redress damages caused by humans
• Water conservationists
• Create an extensive megapore system that channels
  precipitation into the water table

15
Improved water status Higher ratio of green
forage

• Prairie dog clipping and digging activities lead
  to
• decreases in transpiring leaf area
• conservation of soil moisture
• changes in soil physical properties
• promotion of water infiltration to deeper soil
  depths

16
Overgrazing Repair

• Prairie dogs can control noxious weeds and native
  invaders which proliferate on overgrazed
  rangeland.
• Reverse soil compaction caused by cattle grazing.

17
Grassland Mosaic

• Prey base Black-footed ferret Swift Fox
  Ferruginous Hawk Golden Eagle Badger Coyote
  Prairie Falcons Bald Eagle.
• Burrows for shelter from weather and predation
  Black-footed ferret Mountain Plover Burrowing
  Owl Prairie rattlesnake.
• Higher Ratio of Green Forage Bison Pronghorn
  Elk Mule deer.
• Birds reported in higher abundance on prairie dog
  colonies Horned Lark Mourning Dove Killdeer
  Barn Swallow Long-billed Curlew Eastern
  Kingbird Upland Sandpiper McCowns Longspur
  Snowy Owl Red-tailed Hawk Kestrel Rough-legged
  Hawk Harrier Short-eared Owl
• Other animals who benefit from the Prairie Dog
  Deer Mouse Northern Grasshopper Mouse Desert
  Cottontail Great Plains Toad.

18
So Why Dont We Get It?