Biogeography Prof. J. Hicke 1

actual observations

derived chloropleth map

Mapping Biogeographic Distributions

Biogeography Prof. J. Hicke 2

Finer resolution mapping

reveals discontinuous populations or individuals that

are hidden by coarse-resolution maps

Mapping Biogeographic Distributions

Biogeography Prof. J. Hicke 3

Biodiversity

Biogeography Prof. J. Hicke 4

Species-Area Curve

Biogeography Prof. J. Hicke 5

Species-Area Curve

Biogeography Prof. J. Hicke 6 Lomolino et al., 2006

Geographic patterns of biodiversity

Biogeography Prof. J. Hicke 7

S at higher elevations is less than that of S at lower elevations

Geographic patterns of biodiversity

Biogeography Prof. J. Hicke 8

atlas.nrcan.gc.ca/site/english/learningresources/carto_corner/eckert.gif/image_view

Large area in tropics allow for greater S

Causes behind patterns of biodiversity

Biogeography Prof. J. Hicke 9

efc.muskie.usm.maine.edu/Landscape_Ecology_for_Planners_files/slide0061_image078.jpg

Intermediate Disturbance Hypothesis

Causes behind patterns of biodiversity

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Where is biodiversity highest?

Causes behind patterns of biodiversity

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Predator controls on biodiversity

Artificial exclusion experiments:

Prey species before: 15

Prey species after: 8

Smith and Smith, 2006

Causes behind patterns of biodiversity

Biogeography Prof. J. Hicke 12

Increases in diversity

with increasing

evapotranspiration (as

an indicator of net

primary production or

energy available for

supporting life)

Causes behind patterns of biodiversity

Biogeography Prof. J. Hicke 13

Lomolino et al., 2006

Historical Human-Caused Extinctions

• Why the earlier extinctions on islands?

• Why the decline in extinctions in more recent years?

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Chapin et al., 2000; Pimm et al., 1995

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Current Extinctions

• extinction rate is 100-1000 times greater

currently than in the geologic past (Pimm et al., 1995)

• at the current rate, 1/2 of all species will

be extinct in 100 years (Wilson, 2002)

• if all species currently “threatened”

become extinct in next 100 years, extinction rates will be 10x current rates

(Pimm et al., 1995)

• regions of endemism dominate extinctions

(Pimm et al., 1995)

en.wikipedia.org/wiki/Image:ExtinctDodoBird.jpeg

upload.wikimedia.org/wikipedia/commons/d/d0/Ectopistes_migratoriusMCN2P28CA.jpg

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Range Collapse

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Pereira and Cooper, 2006; Ceballos and Ehrlich, 2002

Range Collapse

Biogeography Prof. J. Hicke 18 Lomolino et al., 2006

Range collapse + lower populations => increased probability of extinction

Range size effects

large ranges buffer against localized extreme events

Population size effects

smaller size: more vulnerable to

chance events

Extreme/chance events: virus, hurricane, meteor impact, etc.

Range Collapse

Biogeography Prof. J. Hicke 19

Lomolino et al., 2006

Why are extinctions occurring?

Plants: Causes of endangerment

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Lomolino et al., 2006

Why are extinctions occurring?

Biogeography Prof. J. Hicke 21 Lomolino et al., 2006

Species-Area Curves and Extinctions