Overexploitation

Question 1

Declining Population

Paradigm

Answer 1

–  Habitat	degradation,	
loss,	&	fragmentation	
–  Diseases	
–  Pollution	
–  Exotic	predators	&	
competitors	
– Overharvesting

Question 2

Small Population

Paradigm

Answer 2

Inbreeding	
–  Loss of	genetic variability	
–  Chance	fluctuations	
–  Inverse	density dependence	
–  Etc.

Question 3

Overexploitation
•  Estimated to threaten ?
endangered vertebrates in US.

Answer 3

1/4

Question 4

Estimated to threaten ?
endangered vertebrates in
China.

Answer 4

3/4

Question 5

Traditional Systems

Answer 5

Historically,lack of technology
and traditional systems
protected resources in
some areas

Question 6

Over exploitation

Answer 6

•  Overhunting,
overfishing,
overtrapping,
overcollecting, etc.

Question 7

Overexploitation Problematic when

Answer 7

Laws	 that	restrict or	
control harvest	are	
absent, weak, or not	
enforced	
– Demand is too high;

Question 8

over exploitation Complicating

Factors

Answer 8

Technology is	
available	
– Guns vs. bows and	blowpipes	
– Large-scale	
fishing gear	
– Chainsaws vs.	
machetes

Question 9

Commercial Harvesting Maximum sustainable

yield

Answer 9

-The	greatest	amount	of	
a	resource	that	can	be	
harvested	each	year	
and	replaced	through	
population growth	
without detriment	to	
the	population.
-80%	of	world’s	major	
fish	stocks over fished.

Question 10

Commercial Trade

Answer 10

Legal and illegal trade drives decline of many species

Question 11

Process of Overexploitation

Answer 11

Growth of towns, factories, logging camps, mines create a cash
market for natural products.

•  Tradi,onal hunters and fishermen, who formerly harvested for
their own needs (subsistence), begin to harvest to supply the
cash market.

•  Efficient transporta,on allows middlemen to travel longer
distances to bring the harvest to market and provide access to
remote areas. New marketable species are discovered and
exploited as a result.

•  Warehouses and refrigerators allow the catch to be accumulated
at distant collec,on points for shipping.

•  Interna,onal buyers and eager sellers make a world market in
wild species, further accelera,ng overexploita,on

Question 12

Ecological Effects of over harvesting

Monkey dies, Tree dies

Answer 12

Local extinctions	of	
species	such	as	
primates	(seed	
dispersers) affect	
species	interactions,	
ecosystem function,	
make restoration	
difficult.