Overexploitation

Question 1

What are examples of the extent of overexploitation?

Answer 1

1/4th endangered vertebrates in US and 3/4 of Chinese vertebrate species

Question 2

How can politics result in OE?

Answer 2

Civil wars and disruption of trade routes, and selling off land to rurals.

Question 3

How has bushmeat harvesting impact various mammals?

Answer 3

Ungulates, primates, by more than 80%

Question 4

What is the bushmeat crisis?

Answer 4

Consumption of wild animals resulting in isolate plant communities.

Question 5

What is the value of wildlife trade?

Answer 5

10 billion per year, mostly furs from chinchilla, otters and various cat, as well as insect collectors, orchids and cacti’s, or mollusk’s and tropical fish.

Question 6

What is the value of the aquarium trade?

Answer 6

1 billion for 350 million tropical fish in aquarium market.

Question 7

What is CITES?

Answer 7

Convention on International Trade in Endangered Species.

Question 8

What is the general pattern of overexploitation?

Answer 8

Identify wild resource, commercial market developed, populace mobilised to extract until they’re rare.

Question 9

What is maximum sustainable yield?

Answer 9

The greatest amount of a resource that can be exploited from a population and replaced through population growth.

Question 10

How is this calculated?

Answer 10

Ymax = rB/4 (r being maximum population growth rate, B being carrying capacity

Question 11

How much of fish populations are overexploited?

Answer 11

80%, being an important source of protein in developing nations.

Question 12

What limits regulating MSY?

Answer 12

Passing over international borders, as well as want to satisfy businesses

Question 13

What are risks with MSY?

Answer 13

Human error overestimation or inherent environmental fluctuations

Question 14

What is an examples of the risks associated with MSY?

Answer 14

Canada harvested much cod off the coast of Newfoundland during 80’s, where 1% of COD remained, forced to close and lose 35,000 jobs.

Question 15

How much fish harvest is wasted?

Answer 15

25% majorly through bycatch.

Question 16

What are the consequences of overexploitation?

Answer 16

Food provision, health hazards, natural disasters, degradation/slow recovery of natural ecosystems.

Question 17

How do current extinction rates compare to background?

Answer 17

1000 times higher.

Question 18

Why is the bushmeat crisis important to address?

Answer 18

Its link to food insecurity, emergent disease risks, and land-use change.

Question 19

What is the current status of terrestrial mammals by IUCN?

Answer 19

1169 of the world’s 4556 are threatened with extinction.

Question 20

How many of IUCN listed mammals are primarily threatened by hunting?

Answer 20

301 species, representing 12 of the 26 extant terrestrial orders, being 7% of terrestrial mammals and 26% of all threatened terrestrial mammal species.

Question 21

Which orders of mammals are most threatened?

Answer 21

Primates, even-toed ungulates, chiroptera, marsupials, rodents, carnivores.

Question 22

What are the consequences of hunting with traps and snares?

Answer 22

Unselective bycatch(25% goes to waste) as well as 1/3 of animals escaping with injury.

Question 23

What is the extent of hunting in the Amazon?

Answer 23

89,000 tonnes with a market value of $200 million annually.

Question 24

Why is the removal of large bodied herbivores significant?

Answer 24

Their top-down control on ecosystems balance environmental factors, such as seed dispersion, and may result in mesopredator release.

Question 25

How are animals adapting to hunting?

Answer 25

Changing avoidance behaviours to become more nocturnal or cryptic.

Question 26

How does this perpetuate zoonotic disease?

Answer 26

Hunting/butchering allow high levels of contact of bodily fluids.

Question 27

What diseases are zoonotic in origin?

Answer 27

Ebola, HIV1/2, Antrhax, Salmonellosis, Simian foamy virus etc.

Question 28

Why does selective removal of mammals perpetuate zoonotic diseases?

Answer 28

Decrease in larger mammals increases abundance of rodents, who are particularly effective at transmitting diseases.

Question 29

How has megafauna biodiversity changed since the Pleistocene?

Answer 29

Americas megafaun more diverse than present-day Africa.

Question 30

What is Trophic Downgrading?

Answer 30

This is where apex predators have been extirpated over large geographic regions.

Question 31

What role do megafauna have?

Answer 31

Ecosystem engineers, their large size had impact on forest structure by breaking/knocking down trees, thus modern day promoting savannah grasslands formation and inhibition of woodland regeneration.

Question 32

Why is modern pasture-based grasslands different operationally?

Answer 32

Concentrations of nutrients and inhibition of nutrient flow throughout ecosystems.

Question 33

Why is breaking down of vegetation important?

Answer 33

Opens closed canopies and destruction of woody vegetation, African elephants being twice as important in determining tree fall than fire frequency.

Question 34

How might megafauna decline lead to forest loss?

Answer 34

Trees reliance on dispersal through defecation, shown in the Amazon forest.

Question 35

How did megafaunal changes impact community assembly?

Answer 35

Canids partitioned their climatic niche, yet did not expand into abiotic niche vacated by apex predator extinction, as humans may have out-weighed intra-guild competition benefits.