Species Diversity

Seven kinds of rarity

From Deborah Rabinowitz

Pigweed – widespread, truly common

Red Mangrove – rare – large range, narrow habitat, large populations

Pygmy Cypress – rare –small range, wide habitat, large populations

Haleakala silver sword – rare – small range, narrow habitat, large population

Beach tiger beetle – rare – small range, narrow habitat, large population

Bristle grass – rare –large range, wide habitat, small populations

Peregrine Falcon – rare –large range, wide habitat, small populations

Pacific Yew – rare –large range, narrow habitat, small populations

Osprey – rare – large range, narrow habitat, small populations

Dry stone wall – SW England – home of wall whitlow grass

Malaysian tapir– rare –small range, wide habitat, small populations

Alpine Lily - rare –small range, narrow habitat, small populations

Giant Panda - rare –small range, narrow habitat, small populations

World Conservation Monitoring Centre categories for rare species

• Extinct – not definitely reported in 50 years• Endangered – taxa in danger of extinction and whose survival is unlikely if current

trends continue• Vulnerable – taxa likely to move into endangered category in near future if current

trends continue (USFWS calls this group threatened)• Rare – taxa with small world populations that are not at present endangered or

vulnerable but are at risk• Indeterminate – taxa known to be endangered, vulnerable or rare but where there is

not enough information to say which category applies• Out of danger – once endangered, vulnerable or rare but now considered relatively

secure• Insufficiently known – taxa that are suspected to be endangered, vulnerable or rare

but not enough is known to be sure• Threatened – any taxa considered endangered, vulnerable, rare or insufficiently

known• Commercially threatened – taxa not currently threatened with extinction but where

all or most populations are threatened as a sustainable commercial resource

IUCN Red Data Books

Thylacine – Tasmanian wolf - Extinct?

Black rhino – Endangered

Nile crocodile - Vulnerable

Wood duck – Out of Danger

Atlantic cod – vulnerable & commercially threatened

Atlantic cod – amount caught

Headlines about U.S. backlog of candidate endangered species

• ENDANGERED SPECIES: Obama admin confronts 'candidate species' backlog (Greenwire, 09/08/2009)

• Endangered Species Backlog to Decrease Under U.S. Work Plan By William McQuillen - May 10, 2011 3:45 PM CT

Backlogged candidate species – Florida bonneted bat and streaked horned lark

Climate and distribution• Climate, particularly

temperature and precipitation, influences the distribution of the earth's organisms

• In each major kind of climate, a distinctive type of vegetation develops - for desert plants occur in arid (dry) climates, grasses with semi-arid climates and forests with moist climates

• Certain animals, fungi and other organisms are associated with particular vegetation types

Biomes

• A Biome is a large, relatively distinct terrestrial ecosystem characterized by particular climate, soil, plants and animals, regardless of where it occurs on earth

• A biome's boundaries are determined by climate more than by any other factor

Biomes

Limits to Biome Distribution

Limits to Biome Distribution

Anthropogenic Biomes – fromEllis and Ramankutty 2008

Global Patterns of Species Richness

Global Amphibian Diversity

Global Patterns of Species Richness

Measures of Biodiversity

• Species richness – the number of species in an area – the simplest measure of biodiversity

• Species evenness or equitability – the relative proportion of number of individuals of each species in an area

• Often richness and evenness are combined into a Species Diversity Index

Explanations for Global Patterns of Species Richness

1) Morphological diversity, spatial heterogeneity2) High average rarity - no monocultures – in tropics3) Climatic constancy of tropics4) Geological age5) Special adaptations in extreme (harsh) environments6) Competitive "balance"7) Alternating competitive advantages8) "All niches filled theory" - saturation of community9) Productivity

from A.R. Wallace - 1878

Richness andProductivity

Richness andStructural Diversity

Environmental harshness

Richness and Climatic Variability

Richness and Environmental Age

Last Glacial Maximum

South American Rain Forest – Today and Past Refuges

Richness and Environmental Age

Richness and High Average Rarity

Global PlantRichness

Local CentersOf Diversity

Quality ofData

Richness and High Average Rarity

Endemic Plant Species Globally

Richness and High Average Rarity

Endemic Plant Species Globally

Richness and High Average Rarity

Endemic Plants in Africa