Island Ecology Flashcards
Give the key evolutionary factor of islands
Usually have rapid evolution of species.
Why are islands usually badly damaged ?
Due to agriculture, tourism, alien species
BUT usually have huge scope for restoration.
How can eco tourism be done well ?
When it is non intrusive and run by local people.
Give some examples of islands.
Lakes (within sea of land)
Mountain tops (high altitude)
Habitat fragmentation
(Heathland, Caledonian pine)
State some species area relationships
Islands have fewer species in comparison to the mainland
Big islands have more species than small islands
Close to shore islands have more species than those further away
Give the 2 reasons for species area relationships
Habitat diversity
More habitats on continents
Equilibrium theory
The number of species on an island is a balance between immigration and emigration/extinction.
On a blank island, describe the graph for immigration.
Will start high (island blank space)
Will be higher immigration rate for closer or large islands
Immigration rate will decline until you reach the number of resident species
On a blank island, describe the graph for extinction
Will start at 0
Will increase randomly due to unnatural and natural means
Where is the dynamic species pool on an island ?
In the crossover between extinction and immigration.
Here the population is at equilibrium.
What does habitat fragmentation lead to ?
Islands
Give some examples of habitat fragmentation.
Ancient broadleaf woodlands
Heathlands
Caledonian pine forest
Tropical rain forest
Give the 2 main effects of habitat fragmentation.
Reduced Area
Edge effect
Habitats will differ from the centre of the habitat to the outside edge
What is prone to extinction following fragmentation ?
Predators
Large species
Habitat specialists
Why is edge effect damaging in habitat fragmentation ?
Proportionally more of the habitat will be affected and degraded
Light, wind, water have a bigger impact
How can we prevent habitat fragmentation ?
Wildlife corridors
What are the disadvantages of wildlife corridors ?
They are expensive
Difficult to maintain
No field evidence that they are effective until recently
Can wildlife corridors slow rates of extinction
Yes, research by the university of Nottingham at the peak district revealed this.
Wildlife corridors benefit predators more than non predators, True or False ?
True
Describe the cascading effect of the large frugivores going extinct on the palm population, in the Brazilian Atlantic Forest
Large Frugivores extinct
Large seeds no longer consumed by small birds remaining
Palms Reduce seed size
Increases seed mortality (reduced energy reserve) in dry conditons
Small seeds produce smaller saplings
Overal decrease in fitness of palm population
What do nature reserves in the modern world need to be ?
Bigger, Better and more connected
What is edge effect ?
Where habitat differ from the centre of the habitat to the outside edge
