island biogeography. what is island biogeography? a field within biogeography the study of the...

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ISLAND BIOGEOGRAPHY

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Page 1: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

ISLANDBIOGEOGRAPHY

Page 2: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

What is Island Biogeography?

• A field within biogeography the study of the distribution of species spatially and

temporally

• Establishment and explanations of the factors which affect species richness of natural communities

Page 3: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

History• Founded by Robert MacArthur

and E.O Wilson (ecologists) in the 1960s

“The Theory of Island Biogeography”

• Intention of predicting the number of species that would exist on a newly created island

• Began on islands extends over to other

biomes

Page 4: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

“Because islands are small geographic units with distinct boundaries, they serve as useful models to illustrate the mechanisms of biogeographic phenomena. Intensive ecological studies on islands have provided key insights into invasion and colonization patterns, dispersal mechanisms, and extinction rates.”

- Encyclopedia Britannica

Page 5: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

Isolated populations can become genetically and morphologically distinct from the original

('source‘) population on the mainland over a period of time, whether through natural

occurrences or in relation to the new environment.

Page 6: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

Principle of Island Biogeography“No island will contain the species of the mainland

which served as the sources for colonization (MacAuthur 1972).”

Immigration of species- Terrestrial

species(difficult)- Aquatic species

(easy)

Biodiversity of an island is always build on the species from its Mainland.

Hence, the Mainland contains bigger Biomass

Two significant factors that contribute to the rate of species change are:

1) the area of the island 2) It’s distance from the mainland source.

Page 7: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

Formation of ‘new species’

New species migrate from other areas (usually mainland) and sometimes result in the extinction of the existing species• Competition• Genetic inbreeding

Page 8: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

Reaching EquilibriumThe species on the island reaches dynamic equilibrium in population size and species diversity

through the process of migration and extinction.

• Once equilibrium is achieved:– the biomass of the island stays the same– the composition of species will change

Page 9: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

• Evolution is a significant process only on islands that are large and stable

• On an unstable island, species cannot survive longer to undergo natural adaptation

Page 10: ISLAND BIOGEOGRAPHY. What is Island Biogeography? A field within biogeography  the study of the distribution of species spatially and temporally Establishment

How can we use these principles when designing conservation areas?