Class notes
Island Biogeographics
- Course
- Institution
Covers relationships between area size and species abundance and diversity, and a study called the Biological Dynamics of Forest Fragments Project.
[Show more]
Seller
Follow
chloegalvin
Content preview
EcologyLecture 10 Island Biogeography 17/03/21
Species-area relationships
- There is a positive relationship between species richness
and geographical area.
- Larger areas hold more species, as they have more habitat
types, greater vegetation diversity, and greater altitudinal
range.
- E.g. Central Mexico, 20 caves studies, and the bat species
were counted. Caves with higher variation in humidity
have more bat species, and larger caves have more
variation in humidity. The microclimate is important:
minimise energy expenditure while roosting. Different species have different requirements.
- Large islands also have more species than small islands. Islands closer to the source
population tend to have greater species richness.
Island biogeography theory
- MacArthur and Wilson sought to understand how and why island size (area) and distance
from source combined to determine species diversity.
- They came up with the idea of the idea of the equilibrium theory of island biogeography.
Essentially the number of species on an island depends on a balance between immigration
rates and extinction rates.
- If a new island is formed, then the island is open to colonisation from the mainland
population. As the new species arrive, the island begins to fill up. At first, immigration of new
species is high, but this rate slows down as the number of new species arriving slows down.
Eventually the number of new species arriving reaches zero, likely because all that could
have made it from the mainland have done so.
- But as the number of species on the island goes up, the rate of extinction also goes up. With
more species, more species are more likely to go extinct. As more species arrive, population
sizes are likely to go down (due to competition for resources and the arrival of
predators/parasites).
- Small sized populations are much more likely to go extinct, so smaller islands have higher
extinction rates.
- Thus, the actual number of species on an island is a balance between immigration and
extinction.
Conservation applications
- The Biological Dynamics of Forest Fragments Project (BDFFP) – began in 1979.
- Created islands of 1, 10, 100, and 1000 hectares created. Controls areas of same size
surrounded by rainforest.
-
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller chloegalvin. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.11. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67474 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now