Transcript How Many Animals Do We Want to Save?

“Toxic Garbage Island” movie tonight
W 4/21 at 5pm in JES A121A
Exam #4 W 4/28
(bring cheat sheet)
Items (plastic)
removed from the
gullet of a fledgling
Laysan albatross
http://gadgets.boingboing.net/2007/
08/31/plastic-litters-our.html
Interactions include area, climate,
competition...
Biodiversity “hot spots” have plentiful
resources and large numbers of species
Fig 56.17
Increased numbers of one species can reduce
the population of other species
Fig 54.3
Competition limits where species can live
Fig 54.3
niche- the specific environment
where a species lives
Niche overlap
leads to
competition.
Prolonged direct competition is rare.
Prolonged
direct
competition
is rare.
Fig 54.4
Where these
species
overlap, they
do not
compete.
Biodiversity “hot spots” require both
abundant resources and diverse niches.
Fig 56.17
Changes in Extinctions and Biodiversity
Why are species going extinct?
"Global Biodiversity" Chapman & Hall, World Conservation Monitoring Centre, London, 1992
Most of human history includes critical and
profound interactions with other organisms.
That is now diminished or gone.
How many animals do we need to save?
How Many Animals Do We Want to
Save? The Many Ways of Setting
Population Target Levels for
Conservation
ERIC W. SANDERSON
November 2006 / Vol. 56 No. 11 BioScience 911
Can a number of individuals be set?
Can a number of individuals be set?
Extreme examples:
•Ecotourism want the largest possible
population
•Mining or Agriculture would like none or
somewhere else…NIMBY
What are the consequences of setting the
wrong number?
•Too high
•Too low
A population of a
few individuals
cannot survive
Extinction
Vortex
Can a number of individuals be set?
•Scientists are reluctant to set a specific
number
•Policymakers want information from
scientists
How many animals do we want to save?
Complex interactions of science, economics,
and ethics.
Yellowstone NP
is not big enough
to support a
viable grizzly
bear population
How many animals do we want to save?
Sanderson’s proposed solution:
How many animals do we want to save?
Sanderson’s proposed solution- multilayered
approach:
1. Demographic sustainability
Minimum Viable Population- number of
individuals that allows animals to exist free
from human interference.
How many animals do we want to save?
Sanderson’s proposed solution- multilayered
approach:
1. Demographic Sustainability
2. Ecological Functions
Ecological Functions (aka ecosystem services)
Ecosystem benefits- seed dispersal,
pollinators, nutrient recycling
These functions cannot practically or
economically be carried out by humans
How many animals do we want to save?
Sanderson’s proposed solution- multilayered
approach:
1. Demographic Sustainability
2. Ecological Functions
3. Human Use and Interactions
How many animals do we want to save?
Sanderson’s proposed solution- multilayered
approach:
1. Demographic Sustainability
2. Ecological Functions
3. Human Use and Interactions
4. Can we return animals to levels that existed
before humans had a negative impact?
Instead of a single number…A number for
each level can be determined.
How many animals do we want to save?
1. Demographic Sustainability
2. Ecological Functions
3. Human Use and Interactions
4. Can we return animals to levels that existed
before humans had a negative impact?
“Toxic Garbage Island” movie tonight
W 4/21 at 5pm in JES A121A
Exam #4 W 4/28
(bring cheat sheet)
Items (plastic)
removed from the
gullet of a fledgling
Laysan albatross
http://gadgets.boingboing.net/2007/
08/31/plastic-litters-our.html