Island Biogeography

Mangrove islands off the Florida coast

Mangrove Island Close-Up

Dan Simberloff on MandolinNick Gotelli on Guitar

Simberloff’s defaunation experiment on Mangroves

Simberloff’s defaunation experiment on Mangroves

Results from Simberloff’s Experiment

Results from Simberloff’s Experiment pt. 2

Island Effect

Why are there fewer species on islands than on equal sized areas of mainland?

• Differences purely to area?

• Differences due to mainland having more complex habitat?

Bracken Fern

Bracken Fern - Australia

Number of species found on Bracken Fern

Picture Winged Drosophila

Picture Winged Drosophila – more than 500 species from 1 ancestor

Picture Winged Drosophila – more than 500 species from 1 ancestor

• http://www.youtube.com/watch?v=x-r_YhATOYA&list=PL6C606070246F1C81&index=6

Cichlid Diversity

African Rift Lakes

Cichlids from Lake Tanganyika (left) and Lake Malawi (right)

Age of African Rift Lakes

• Lake Tanganyika – 12 million years old; about 250 species of cichlids; 80% endemic

• Lake Malawi – 5 million years old; about 700 species of cichlids; again 80% endemic

• Lake Victoria – 250,000 to 750,000 years old; about 400 species of cichlids – over 80% endemic

The dodo

What makes species vulnerable to extinction?

What makes some populations or species vulnerable to extinction?

What makes some populations or species vulnerable to extinction?

• Rare species are more vulnerable to extinction

• Remember Rabinowitz – three factors determine rarity:

1.Geographic range

2.Width of habitat use

3.Local population size

Passengerpigeon

Passengerpigeon

Allee Effect

• Some species have a minimum requirement for population size in order to successfully breed

Characteristics that predispose species to becoming extinct

1. habitat overlap - the species occupy habitat that is desirable to humans and lose out in competition with humans for the habitat - tallgrass prairie species

2. human attention - species suffer because singled out by humans - either desired as food or fur and hunted heavily (passenger pigeon, dodo, northern elephant seal); or disliked by humans and killed as varmints (wolves, African wild dogs)

3. large home range requirements - animals needing large areas can’t find large enough areas in human dominated landscape - California condor, polar bear

4. limited adaptability and resilience - salmon return to natal stream to reproduce; won’t go elsewhere

Habitat overlap – Konza Prairie, Kansas

Human attention – African wild dog

Large Home Range Requirements - California Condor

Limited adaptability and resilience - Coho salmon

Salmon Life Cycle

Coho Salmon support 137 species

Additional factors• Species in which population size is declining

• Animal species with large bodies

• Species that are not effective dispersers

• Seasonal migrants

• Species with little genetic variability

• Species with specialized niche requirements

• Species usually found in stable, pristine environments

• Species that form permanent or temporary aggregations

• Species that have not had previous contact with people

• Species closely related to other species that have gone extinct or that are endangered

Species in population decline – barn owls

Species with large home ranges – Polar bear

Animals with large bodies

Species that are not effective dispersers- Freshwater Mussels

Seasonal migrants such as Blackpoll Warbler

Species with little genetic variability – Madagascar fish eagle

Species with specialized niche requirements – hummingbird flower mites

Species usually found in stable, pristine environments

Species that form permanent or temporary aggregations

Species with little or no prior contact with people –

Western Australia flora

Species related to other extinct or endangered species - Cranes

Worldwide Endangered Species

Endangered tree species - worldwide

Rare and Endangered Species in Japan

Endangered species in Canada and the US – as of 1990’s

Threatened and Endangered Species

ThreatenedAndEndangeredSpecies inIllinois

Four-toed salamander – found at Green Oaks

Past Climate Change

Coring Glacial Ice

Ice Core Data

Pollen core data collection

Pollen Core Data

Distribution of North American Trees in past 16,000 years

Black-tailed prairie dog

Northern bog lemming

Eastern chipmunk

Global Ice Coverage Last Ice Age

Rainforests in: a. Glacial period, b. Inter-glacial period

Globalcarboncycle

Carbon dioxide concentration at Mauna Loa

Change in Average Global Temperature

Statistics and climate change

• http://www.youtube.com/watch?feature=player_embedded&v=e0vj-0imOLw

Surface temperature trends from 1800-2009

• http://www.guardian.co.uk/environment/video/2011/oct/20/berkeley-earth-climate-change-video

Model predictions of global temperature increase

Predicted surface change 1960-2060

Current distributions of biomes

Predictions for biomes after global warming

The Earth Ice Free

Global Ice Coverage Last Ice Age

Will species be able to survive current climate change?

• Maybe

• Maybe not

New Complications with Climate Change

1. Current species and populations may already be stressed by habitat loss and environmental degradation

2. Habitat loss will make it harder for species to migrate to new areas

3. Global temperature may increase to temperatures that are much greater than species experienced in the past

4. Rate of global climate change is probably faster than in geologic past

Pikas may run out of mountaintop