global patterns of species richness global amphibian diversity
TRANSCRIPT
Global Patterns of Species Richness
Global Amphibian Diversity
Wallace’s hypotheses for higher species diversity in the tropics:
1. Productivity
2. Spatial heterogeneity; morphological diversity
3. High average rarity – no monocultures
4. Climatic constancy – little seasonal variation
5. Geological age
6. Special adaptations required for “harsh” environments
7. Greater competitive “balance” in tropics
8. Alternating competitive advantages
9. All niches filled – saturation of community
Early Island Biogeography
IslandHabitats inBaltic Sea
Reptile and Amphibian Species Area Curve for Caribbean Islands
Habitat IslandsIn the Great BasinTop – Birds,Bottom - Mammals
Species Richness related to Island Size and Island Isolation
Species-Area Curves for Islands
S = cAz where:
S = number of species
A = area of island
c = constant for habitat type - forest, desert, grassland
z = slope of the curve - predicted to be 0.263, but actually varies with dispersal ability
Ant speciesOn NewGuinea andNearbyIslands
An area of island will have fewer species than equal sized area of continent
The slope of the line plotted for species-area curve is
larger for species with poor dispersal abilities Oceanic islands
birds - New Guinea islands z=0.22beetles - West Indies z=0.34land plants - Channel islands z=0.37
Habitat islandsbirds - Andes paramo z=0.29birds - mtns of Great Basin z=0.165mammals - mtns of Great Basin z=0.326inverts -caves in West Virginia z=0.72
Island Biogeography
Species Dispersal to Islands
Cape May Warbler on a Ship
Krakatoa pre-eruption
Looking at Volcano Rakata
Krakatoa mid-eruption
Map of Krakatoa pre-eruption
Landsat Image of Anak Krakatau and Krakatau
Dan Simberloff and Mangrove Islands
Simberloff’s defaunation experiment on Mangroves
Simberloff’s defaunation experiment on Mangroves
Results from Simberloff’s Experiment
Islands recovered to pre-defaunation number of species, but only 30%of original species resident on each island returned after defaunation.
BrackenFern
Bracken fern stand Australia
Number of species found on Bracken Fern
Professor Axel Meyer – Cichlid Man
Lake Malawi Cichlids
Adaptive radiation within cichlid lineages