Conservation
Elongated Elephant
Bulte, Van Kooten
• CITES
– Bans TRADE in endangered species
– Reduces Demand
– Should be good for elephants, etc
– (Same argument for Viagra saving Rhinos)
Poaching
• Poaching model is the fishing model, but
adds enforcement.
– P price
– E effort (poaching
– B enforcement effort
– X stock
– F fine (punishment)
• kExp is revenue as in fishing
• C(B) E is cost of poaching and increases in B,
enforcement. Costs of evading getting caught.
• T E (zkEx +p) expected value of punishment
– TE is likelihood of getting cauth
– Last element is the fine where z is a parameter
– Notice that this term has two E’s which drives
everything
Zero Profits for Long Run
• 0 = kExP – C(B) E – TE (zkEx +p)
– Zero long run profits
– Gives E(P, B, …)
– Point is that poaching increases in price and
decreases in enforcement.
– h = kEx is harvest
Look at the Table
• CITES goes Along with
• DECREASED enforcement
• Reminiscent of Kip Viscusi’s idea of a
taste for danger. (Gov makes you wear
seatbelts, so you drive faster to get in your
danger quota.)
Social Planner Problem
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1 Elephant = 4.7 cows in terms of forage
D(x) is foregone forage
W(B) costs of enforcement
R(x) are the existence values and tourism
values
• zTh is the value of the gov’t seized ivory
• Q is total sold ivory including legal harvest
and illegal
maximand
• At each time
• P(Q) Q +R +zTh –cE –D(x) – w(B)
• S.t. dx/dt = G(x) – h – y
• Assumes CITES, only a local market
With trade
• Here P(Q) is world price
– Big question is how much local price is below
world price, even after otpimization.
• Now problem is linear in y, so get most
rapid approach
Model is really…
• Most efficient way to harvest animals
– Poach or cull
• Right number of animals
• Since CITES doesn’t prohibit gov’t from
culling, it just reduces price.
Bulte and KC
• Program this up with Zambia values and
they get
Payoff Slide
So
• Elephants are on their way DOWN, Cites
or no.
• CITES doesn’t do that much.
• Underlying reason—strong local market,
possibly driven by smuggling.
San Joaquin Kit Fox
ESA
• Endangered Species Act
– Listing
– Take
• Includes annoying
• Applies to private land too
– Habitat Conservation Plans
• Can include a whole county
• E.g. each acre of toad habitat you take you have to
buy 5 acres and preserve them elsewhere
• The ESA was not thought to be radical
when it was passed. Barely any debate.
• Court action and interaction with NEPA
made it a very powerful tool
• The HCP element allowed negotiation and
it is now just another part of doing
business
ESA
• See Gardner Shogren
• Most listed animals aren’t going to recover
• There is far too little money allocated to
recovery plans to make progress
• Total value of the animals would need to
be improbably high for it to be right for
Congress to allocate that much money
Who gets listed?
• Amy Ando sets up model where listing
depends on things like “fur”
• And also depends on pressure group
activity
• She records whether there was comment
for or against a listing. That is her
measure of pressure.
• Payoff to a group depends on the other
groups actions. The more pressure the
other group applies, the more beneficial it
is for the group to apply pressure.
• Defines a game where the Nash non coop
soln is of the form P(i) = a + bP(j) for the
two groups i and j.
• comes down to lobby is a function of
furriness and other groups action.
• finds that other groups action doesn’t
matter
• but furriness does.
Bollworm
Pests
• Pests are un elephants.
• They are small
• We want them dead but
– We don’t want to kill ourselves and everything
else killing them
Pest Control
• Cotton, veggies are a big users of pest control
• Obvious problem is that pest control materials
can
– Run off and kill good things
– Bio accumulate and kill bigger animals
• Like ddt and birds
– Some materials cause cancer, reproductive harm and
so on.
– FERPA regulates these things
– Sunding, Zilberman, Siebert worked on costs of
regulation in CA
Cotton
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Livingston, Fackler
Two pests, boll wevil and budworm
Two controls: BT cotton and pyrethroids
Also a refugia
– Place where we don’t use control/controls
• Problem: Bugs become immune to
controls.
Biology
• Assume single gene for resistance
– x,X alleles for resistance/suspectibility for BT
– y,Y for pyrethroids
– x(t,i) proportion of allele in growing season t
and generation i. Multiple generations per
season
– g is probability of xy etc
• Since each plant has two (is diploid)
alleles there are 9 genotype frequencies.
• See paper for a list and their probabilities.
• Each plant is two choices from the four
possible xy combos with their frequencies
g.
• This makes a 9 vector of frequencies for a
generation
• Pests spend some time in refugia and
some in cotton.
– first generation, 95% of pests in non selective
environment
– then 98% of budworms in cotton
– and so on.
• Different survival rates in refugia vs in
sprayed/Bt cotton.
• So at end of generation, different percent
of alleles in population.
• Bigger refugia, higher percent of
suspectibles maintained.
Problem
• Max money
• subject to allele dynamics
• choose refugia size, how much to spray
• findings: use less sprayed refugia and
less refugia all together.