L2 Paradigms in conservation biology

Question 1

what does ‘declining pop paradigm’ focus on?

Answer 1

the cause of smallness and the cure

Question 2

what does the ‘small pop paradigm’ focus on?

Answer 2

the effect of smallness on the persistence of a pop

Question 3

What are the 4 main causes of a declining population?

Answer 3

• Overexploitation
• Introduced species
• Habitat destruction & fragmentation
• chains of linked extinctions
  a 5th point is ‘extinction synergies’ - a combined effect of all of these causes

Question 4

what is a case study example of habitat destruction/ fragmentation?

Answer 4

Passenger pigeon in the 19th century, they needed a critical population size as they were social feeders.

Question 5

What is stochasticity?

Answer 5

The quality of having an element of randomness/haphazardness to a plan or process

Question 6

What are more likely to negatively influence a small population?

Answer 6

Demographic stochasticity
Genetic stochasticity
Environmental stochasticity
Catastrophes

Question 7

What is demographic stochasticity?

Answer 7

variability of sex ratio & growth rates. So in a small population the structure of the pop will be all over the place & this will have a detrimental effect.

Question 8

What is environmental stochasticity?

Answer 8

Random environmental fluctuations, often resulting in population change

Question 9

describe the term extinction vortex

Answer 9

the extinction vortex is the term used to describe the process that declining populations undergo when a mutual reinforcement occurs among biotic and abiotic processes that drives population size downward to extinction (Brook, Sodhi & Bradshaw 2008)

Question 10

How would you use the declining population paradigm in conservation? (5 steps)

Answer 10

1) Use scientific method to deduce both why the pop declined and which agent caused it. Don’t assume folk wisdom is correct lay (untrained) or scientific.
2) Remove or neutralise the agent of decline.
3) Release a probe group to confirm the cause has been deduced correctly
4) If so restock unoccupied areas by translocation or, if the remnant pop is too low to risk further reduction, breed up a protected stock asap, as near to problem site as poss and release.
5) Monitor the subsequent re-establishment

Question 11

what management intervention techniques could you use for critically endangered species in wild populations and habitats? (8) (Maguire et al., 1987)

Answer 11

1) Translocating individuals or genetic material
2) Raising the carrying capacity (artificial feeding)
3) restricting dispersal (fencing)
4) Fostering and cross-fostering young
5) Culling
6) Preserving habitat
7) Restoring habitat
8) Reducing mortality (vaccinations, parasite & predator & poaching control)

Question 12

what management intervention techniques could you use for critically endangered species in captive only? (3) (Maguire et al., 1987)

Answer 12

1) maintain captive breeding pops for reintroduction & or repeated captivity
2) Genetic and demographic management
3) maintaining gametes or embryos in ‘miniature zoos’ i.e.e freezers

Question 13

what management intervention techniques could you use for critically endangered species in captive and wild pops? (2) (Maguire et al., 1987)

Answer 13

1) re-introdcution of captive reared individuals or genetic material to occupied or unoccupied habitat
2) continued capture of wild individuals or genetic material for future captive propagation (breeding)