Week 1 - History of Conservation Biology Flashcards
How did Conservation Biology begin?
Conservation biology as a science was born in the 1980’s and is still in its infancy. Prior to 1980, conservation biology only concerned studies on the habitats of endangered species.
Two influential books
1. Soule M. E (1996) Conservation Biology)
- Soule M. E (1987) Viable Populations for Conservation Cambridge
What is the SLOSS debate?
The SLOSS debate was a debate in ecology and conservation biology during the 1970’s and 1980’s as to whether a single large or several small (SLOSS) reserves were a superior means of conserving biodiversity in a fragmented habitat.
Can you think of situations
where several small might actually be better than a single large?
If a disease breaks out there is no isolation so the disease is more likely to spread.
Cyclones, bleaching etc and other disturbances might miss other islands compared to one big island.
Can you think of situations
where single large might actually be better than a single large?
If you have a larger area you can have a larger population there. So you can support a larger population and possibly higher biodiversity.
Island Biogeography theory: Rates of immigration will be typically higher and rates of extinction will probably be lower because you have a larger population.
Remember this is not necessarily right, it is just under Island biogeography theory.
Island biography theory would choose a large island because it is not taking disturbances into account, it is only talking about immigration and extinction rates.
What is the 50/500 Rule?
The second major field of interest in conservation science concerned the behaviour of
small populations he
50/500 rule was a bold proposal to aid managers who wanted a rule of thumb for re-
establishing viable populations. It was realized that if populations were too small there
would be genetic problems due to inbreeding. Genetic studies tell us that this will happen
if the effective population size is less than 50. In fact, if the effective population size is less
than 500 there will be random loss of genetic variation through genetic drift. This loss of
genetic variation impairs the future reproductive success of small populations.
So the
theory argues for an absolute minimum of 50, but a preferred minimum of 500 to establish to establish viable populations.
What is the main criticism of the 50/500 rule?
The main criticism of this theory is that it does
not consider the demographic and reproductive characteristics of individual species and
local environmental conditions, which in most circumstances, tend to outweigh problems
associated with genetic factors.
Why are reserves with corridors better then reserves without habitat corridors?
Reserves connected by corridors
of undeveloped habitat are superior to completely isolated ones, as this essentially
connects the sub-populations and reduces the chance of extinction
What arrangement is best? A triangle or a line of reserves?
The triangle on is more connected so it would be considered better for island biogeography theory since you could support immigration.
Habitat loss versus habitat fragmentation
Metapopulation models are an important tool for exploring the separate effects of habitat loss and fragmentation
major causes of extinction of threatened terrestrial species
The key metric is understanding how well habitat fragments are connected through dispersal. Therefore, we need to understand how well habitats have become fragmented through dispersal.
Are they still connected and are animals still moving in between them
Which approaches to terrestrial conservation are not appropriate to marine organisms?
- DO NOT design reserves based on island biogeography (colonisation and extinction rates may be unimportant.
- DO NOT rely on habitat corridors all the time because they may be unimportant since populations are linked to larval dispersal rather than adult migration.
- DO NOT Have MVP rules based on inbreeding and genetic drift that may be unimportant since few populations are as low as 500 and much larger populations may be endangered.
- DO NOT have PVA analysis based on single closed populations that are inappropriate for widely dispersed organisms
Which approaches to terrestrial conservation are appropriate to marine organisms?
- Meta-population models are likely to be more realistic in predicting extinction threats for marine species.
Parentage analysis establishes self-replenishment and multi-directional connectivity among marine reserves in Kimbe Bay, Papua New Guinea
E.g Found 5 generations of Nemo in a single reserve. * Large-scale, multidirectional connectivity among reserves. * Complete description of a dispersal kernel to inform metapopulation models. - Connectivity in commercially important species
Multidirectional connectivity in coral trout Dispersal distances range from 250m to 250km Connectivity in commercially important species Reserves important as Sources of larvae (Williamson et al. (2016) Mol Ecol)
