LEILA DILEMMA
If 90% of a habitat is destroyed and the remaining 10% is saved as a reserve, roughly what fraction of species can you expect to survive long-term?
About half or 50%
What happens to species number as distance from the colonisation source increases?
it decreases
What does Diamond call the process of a reserve slowly losing its excess species over time until it reaches equilibrium?
Relaxation
Even birds that CAN fly sometimes fail to recolonise reserves. Why?
psychological barriers to crossing unsuitable habitats like water gaps
True or False. One large undivided reserve is BETTER than many small scattered reserves for conserving species?
True
Species number S on an island is set by (or approaches) an equilibrium between ____ and ____ rates
immigration and extinction
For a small reserve of just a few km², how quickly can extinction of sedentary birds and mammals be measured?
Within a few decades
Determining incidence function is a method of quantifying _____
survival prospects of a species on islands of different sizes
True or False. Small, common, adaptable generalists are MOST vulnerable to extinction.
False. Large, specialised, or habitat-sensitive species are most vulnerable
Using the rule of thumb (z = 0.30), if you increase island area by 10 times, species number increases by roughly how much?
2x
After 10,000 years, what happened to small land-bridge islands (under 250 km²) in terms of bird species?
They lost their entire excess of species
In figure 6, which species started colonizing smaller islands? (A) Pitta erythrogaster - B tramp or (B) Ptilinopus superbus - C tramp
(B) Ptilinopus superbus - C tramp
This type of reserve allows population to readily colonise or be colonised from
Equidistant Reserves (Principle D)
What does the species-area formula S = S₀Aᶻ (Species-Area Law) tell us?
Species number increases with island area
What are "land-bridge islands" and why does Diamond use them?
Islands once connected to mainlands that became isolated; used to study extinction rates
New Hanover island lost only 22% of its species — but why does Diamond call it a conservation disaster?
Because it lost the rarest, most restricted, and most endemic species