Island Biogeography

Question 0

What kinds of Islands are there?

Answer 0

Water-surrounded islands

• oceanic
• continental
• lake islands

Land-surrounded islands

• virtual islands
• fragmented land

Question 1

Why are islands so special?

Answer 1

• Excellent biogeographical processes
• evolution is evident due to isolation
• home to the weird and wonderful!

Question 2

What are virtual islands? Where are the important?

Answer 2

• agriculture
• fragmented forest
• important to climate change, conservation and agriculture

Question 3

What important concepts are there?

Answer 3

• stepping stones
• corridors
• species area relationships

Question 4

What sinter difference between oceanic and continental islands?

Answer 4

Oceanic
- are not, and never have been connected I a mainland landmass

Continental

• are not, but have been connected to mainland landmass
• only separate due to sea-level rise

Question 5

What input lids Wallace have with the identification of oceanic and continental islands?

Answer 5

• He initially noticed a difference.
• couldn’t originally explain the variance between Bali and Lombok islands.
• invented Wallace’s line between the two islands

Question 6

What did Wallace discover with Bali and Lombok island?

Answer 6

Bali and Lombok separated by small amount of very deep water

Bali

• was similar to java and Sumatra in physical structure and animal/flora species
• mammals present
• less diverse bird species
• continental island

Lombok

• not similar to java and Sumatra
• occupied by many different bird species
• no mammals
• oceanic island

Question 7

What did Wallace find with Aru and Ke islands?

Answer 7

Similar to Bali and Lombok

Aru was similar to nearby mainland
Aru as a continental islands
Ke was not similar to nearby mainland
Ke was an oceanic island

Question 8

What process and speed do species arrive on islands?

Answer 8

Oceanic islands
- evolution is faster that immigration

Continental islands
- immigration is faster than evolution

Question 9

What Island species process types are there?

Answer 9

Local extinction
Immigration
Speciation
Island equalibrium
- some colonisation will result in extinction due to predation or competition
- species number will increase due to immigration and speciation.
- eventually the rate of increase will balance the rate of decrease

New islands have no species at all

Question 10

What are the colonisation rates on oceanic islands?

Answer 10

Two important factors:
Isolation
- the further away from a mainland landmass an island is the liner it take to populate the island

Size

• a large island has more coastal landing space
• also larger inland area to fill
• despite size take longer to populate than a small island

Question 11

What special species traits are there with island species?

Answer 11

Giantism
- Galapagos tortoises

Dwarfism
- minute chameleons in Madagascar

Flightlessness
- kiwi in New Zealand

Question 12

Explain diversity of island species

Answer 12

Fewer species per unit area than on islands than mainland

Jarak island
- 34 species of tree in every 0.4ha plot

Malayan mainland
- 98 species of tree per 0.4ha plot

Question 13

What’s unusual about polarity of islands?

Answer 13

• islands have more polar features and flora than ty are similar to near by mainlands

Eg

• Galápagos Islands loaded on equator and should be tropical. In reality: it is arid
• Canary Islands are located next to Africa but is Mediterranean

Question 14

Are species in islands sub-sets of nearby mainland species?

Answer 14

NO

it is not the reputable nearness of the species which matters, it’s the dispersal power of the species

Question 15

How are island facilitators of dispersal?

Answer 15

Stepping stones

Occupied mainland –> island 1 –> island 2 –> unoccupied mainland

Question 16

Why are island species area curves?

Answer 16

• though that larger islands have more species thank smaller islands
• there is not a linear increase of species and size of islands

2 confusing hypothesises

1. The number of species in and area increase with the size of the habitat
2. Increase in species within increasing size of area occurs at a decreasing rate

Question 17

Talk about the Rakata Theory.

Answer 17

• Krakatoa eruption left and island 1883
• Study of island development started from 1886 to present day
• colonisation not as simple as the theory suggested
• climatic and geographical changes influenced the colonisation and extinction rate

Question 18

What was the process of colonisation in the Rakata case study?

Answer 18

E = eruption

Studied the colonisation of flora on coastal region
E+3 - 9 species
E+14 - 23 species
E+25 - 46 species

Inland plant succession
E+3 - 50% of vegetation were ferns
E+14 - grassland
E+100 - forest cover grassland

Question 19

Could the Rakata theory easily predict the abiotic or biotic factors?

Answer 19

Abiotic factors where easy to predict as they involved aspects such as

• island area
• position
• isolation

Biotic factors were not so easily predicted. For factors such as
- predation
- competition and
- disturbance 
There are not rules