•Exam #2 F 6/27 in class (bring cheat sheet)
Ecology: We are all connected and interdependent
CB 52.12Carrying Capacity
exponential growth
stationary phase
Carrying capacity can be limited by competition
CB 53.2
Competition limits where species can live
CB 53.2
niche- the specific environment where a species lives
CB 53.3
Tree species existing in different niches
SpeciesintroductionsHunting
HabitatDestructionOther
39%
23%
36%
2%Why are species going extinct?
Historical Grizzly Bear range
Current Grizzly Bear range
CB 55.12
Yellowstone Grizzly Bear population increases
63 mi
54 mi
•466 mi of roads •950 mi of backcountry trails•97 trailheads•287 backcountry campsites
Yellowstone NP
CB 55.16
Artificial corridors allow animals to cross fragmented areas
CB 55.18
Where do grizzly bears fit?
Are they important?
How much of our resources should we share with grizzly bears?
CB 55.19
National park
Buffer zone
In Costa Rica they have a two tiered park system:
National Parks- very restricted human activities
Buffer zones- some restrictions on human activities
CB 55.19
National park
Buffer zone
Developed vs Developing nations:
Should/would the US designate such large areas as parks?
63 mi
54 mi
•466 mi of roads •950 mi of backcountry trails•97 trailheads•287 backcountry campsites
Yellowstone NP
Wolves in Yellowstone National Park
The last wolves in Yellowstone (1920’s)
Wolves commonly live in packs
Social vs Solo
Packs can kill larger prey
Packs give the ability to obtain more food, but also mean sharing food, reduced chance of reproduction, and increased chance of diseases.
Wolves are very territorial and will kill intruders
Wolves were re-introduced to Yellowstone in 1995
“hard” release:directly to new location
In Yellowstone used“soft” release:Kept in 1 acre pens to acclimate to new environment
Wolves were re-introduced to Yellowstone in 1995
http://www.forwolves.org/ralph/historical.html
Yellowstone area wolf packs 2004
Wolf deaths 1995-2005
38 deaths= 33%
Currently about 300 wolves 2003- 137 sheep and 66 cattle = $32,000
2004- 209 sheep, 57 cattle, and 6 other animals = $70,000
The cost of wolves in Yellowstone NP:
Estimate millions of dollars in increased visitors
Predator-predator interactions
Predator-predator interactions
CB 55.12
Yellowstone Grizzly Bear population increases
Wolves are decreasing the elk population
Benefits of decreasing herbivore populations
Increased Riparian Habitat
Fig 2
Increased Riparian Habitat
Fig 2
Increased Riparian Habitat
Fig 3
Increased Riparian Habitat
Fig 5
Are wolves responsible?
year1998 1999 2000 2001 1998 1999 2000 2001
Fig 6
Protection vs herbivory
gully depth vs browsing
Fig 6
The greatest difference has been in the deepest gullies, which are at the greatest risk to errosion.
The reintroduction of wolves to Yellowstone NP has had numerous positive benefits.
The reintroduction of wolves to Yellowstone NP has had numerous positive benefits:More food available for other carnivores
Fig 3
The reintroduction of wolves to Yellowstone NP has had numerous positive benefits:Increased Riparian Habitat
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 231
Animal behavior is unpredictable and inexplicable
CB 55.13
Not all habitats are equal
How do stable ecosystems develop?
Primary Succession- the first organisms to colonize bare rock
Secondary Succession- recovery from a disturbance