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Flashcards in Ecological Concepts Deck (18)
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Who proposed island biogeography and when?

MacArthur and Wilson, 1963


What are the two patterns of island biogeography?

Large islands have more species than small islands

Near islands have more species than far islands


What are the two processes of island biogeography?

The farther the island, the slower the immigration rate

Extinction rate is higher on small islands


What provides the source of immigrants for the islands?

The species look on the mainland


How do you work out the equilibrium number of species on an equilibrium model of fauna?

Draw the immigration of new species curve on one side and the species extinction on the other side

Where the lines cross on the graph is where there is equilibrium


What is countryside biogeography?

Where the edges around the habitat can be occupied by other species, rather than being surrounded by an inhospitable sea


What types of islands are there?

Oceanic islands e.g Seychelles

Land bridge islands e.g Britain

Habitat islands e.g forest patches surrounded by farmland


What is a meta population?

A set of local populations occupying various habitat patches and connected to one-another by the movement of individuals among them


Give an example of a forest generalist that can occupy the forest edge and one that can’t:

Tupaia longpipes are a core forest species- won’t occupy edge

Muntjak deer are generalists and can occupy the whole forest


What is the theory of drivers and passengers and who came up with it?

Removing drivers causes a cascade effect

But loss of passengers leads to little change in the rest of the ecosystem

Walker 1992


What is the rivet popping hypothesis and who came up with it?

Species are rivets holding together a complex machine

All species make a contribution to ecosystem functioning

Ehrlich and Ehrlich 1981


What is the insurance hypothesis and who came up with it?

Increasing biodiversity insures ecosystems against declines in their functioning

Yachi and Loreau 1999


What are the three types of positive relationships between species richness and ecosystem functioning?

Redundancy, linear and idiosyncratic


What is the idiosyncratic hypothesis?

The magnitude and direction of changes are unpredictable, as the role of species is complex and varied

The sequence in which species are removed matters


What can ecological resilience be defined as?

The capacity of an ecosystem to absorb disturbance without shifting to an alternative state and losing function and services


What happens if you pass the tipping point of resilience?

It leads to a completely different ecosystem state


What is social ecological resilience?

The whole ecological resilience including humans


What is the definition of minimum viable population?

The smallest size required for a population or species to have a predetermined probability of persistence for a given length of time