Applied Population Biology

Question 1

Metapopula)on models

Answer 1

Stem	from	the	observa,on	that	most	
organisms	of	interest	(threatened	or	
unthreatened)	do	not	exist	as	a	single	
popula,on,	but	as	mul,ple	popula,ons	with	
spa,al	structure

Question 2

local ex-nc-ons a

Answer 2

in a metapopula-on model, are the norm and

expected

Question 3

  Levins Metapopula,on assump,ons

Answer 3

–  Popula,ons are spa,ally structured into local breeding
popula,ons
–  Migra,on among local popula,ons allows
reestablishment
–  Habitat patches have equal areas and isola,on
–  Local popula,ons have independent, uncorrelated
dynamics
–  Migra,on between popula,ons is so low that it has no
real effect on local dynamics of the exis,ng popula,ons
•  i.e. local dynamics occur on a fast ,me scale in comparison to
metapopula,on dynamics.
•  BUT!!! Can alter gene,cs
•  Each subpopula,on has its own birth rate, death rate, and
probability of going ex,nct.
•  Dynamics depend on interpatch distance, dispersal ability,
number of patches.
•  Consequences/Characteris,cs:
–  Can increase the persistence ,me of the en,re popula,on
on the landscape.
–  Suitable habitat is some,mes unoccupied.
–  Some empty patches are needed to prevent the collapse
of the metapopula,on.
–  Ex,nc,on thresholds.

Question 4

• Levins metapopula,on:

Answer 4

network of small patches with
local dynamics much faster than metapopula,on
dynamics. Local popula,ons o^en go ex,nct

Question 5

Mainland-island metapopula,on:

Answer 5

large habitat patch

“feeds” smaller isolated patches. No patches go ex,nct

Question 6

• Source-sink metapopula,on:

Answer 6

Source popula,on
reproduc,ve rate is high enough at low densi,es to
maintain the source popula,on and provide dispersers
for sink popula,ons. Sink popula,ons reproduc,ve rate
not high enough to maintain the sink popula,on.

Question 7

Sources –

Answer 7

good
habitats where
reproduc,ve success
> mortality

Question 8

Sinks =

Answer 8

poor habitats
where reproduc,ve
success<mortality

Question 9

Source-Sink Dynamics

Answer 9

Sinks	may	be	
larger	and	
have	higher	
pop.	densi-es	
–	but	would	
go	ex-nct	if	
not	for	
presence	of	
source	
habitats.

Question 10

Types of Metapopula,ons • Patchy popula-ons

Answer 10

• Dispersal between patches is high
• patch populations fluctuate simultaneously
• colonists rescue patch from extinction
• essentially a sengile, extinction resistant population

Question 11

  Prospec-ng:

Answer 11

long
solo movements
away from natal
territory

Question 12

Dispersed

Answer 12

roosted

off of natal territory

Question 13

– Nonequilibrium metapopula-ons

Answer 13

– Species	in	overall	regional	decline.	
– Con,nuous	recoloniza,on	of	
ex,nc,on-prone	subpopula,ons	has	
been	disrupted.	
– Limited	dispersal.	
– Local	ex,nc,ons	are	prevalent.	
– Typical	of	rare	species	
-habitat	fragmenta,on	
-reduces	popula,on	density

Question 14

• Patch dynamics models

Answer 14

-popula,on abundance defined by
numbers of animals in discrete patches
• Parameters include popula,on size at ,me t, popula,on growth
rates and movement rates for each patch

Question 15

Source sink models-

Answer 15

one type of habitat (source) is
suitable (popula,on growth rate>1) and another type of
habitat (sink) is unsuitable (popula,on growth rate<1)
• Parameters include popula,on size at ,me t, maximum
popula,on size in the source habitat, movement rates, and
popula,on growth rates

Question 16

Standard models

Answer 16

–  Assume panmic,c
structure, with all
individuals equally likely
to interact

Question 17

Metapopula,on models

Answer 17

-Assume	popula,ons	are	
spa,ally	structured	into	
local	breeding	
popula,ons
–  Migra,on	among	local	
popula,ons	allows	
reestablishment

Question 18

Spa,al Explicit Popula,on Models

Answer 18

•   Landscape map
•   Scenario(s) of how landscape will change
•   Popula,on dynamics simula,on
•   Highly complex
•   Lots of parameters and assump,ons