Understanding the Global Biodiversity Crisis

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Understanding the Global Biodiversity Crisis

• EnvS 001
• Dr. Trulio Spring, 2007

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• Information in this talk is compiled from
• Miller (2007), Living in the Environment (15th
  edition).
• Other sources, with dates of material, as noted
  in the talk.

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Whats the Problem?

• Rivot Poppers AnalogyPaul Ehrlich
• 5-100 million species on earth
• Only 1.4 - 1.8 million identified
• But, biodiversity experts such as
• E. O. Wilson estimate that 20-50 could be
  extinct by 2030

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Mass Extinctions/Depletions25-85 of all species
disappear

• 5 mass species loss events in last 500my
• Natural forces, esp. climate change
• Current eventcaused by us!

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What is biodiversity?

• Biodiversity includes not only the many species
  that exist, but also the diversity of populations
  that make up a species, the genetic diversity
  among individual life forms, and the many
  different habitats and ecosystems around the
  globe.
• (Environmental Literacy Council, 2004)
• www.enviroliteracy.org

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What is Extinction?

• Extirpation local extinction a species is no
  longer found in a portion of its range ex
  grizzly bear
• Extinction a species is no longer found anywhere
  on earth ex dinosaurs, passenger pigeon a
  natural and human-caused phenomenon
• Background rate extinction rate w/o humans 1
  spp/million/year

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Current Rates of Extinction

• Current losses 14,000 species per year
  (5000-100,000 depending on of species)
• This rate is 1,000-10,000 times the background
  extinction rate.
• We are now in the worst extinction crisis in the
  last 65 million years!
• Humans are the cause this time.

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Why Extinction is Forever Evolution

• Central concept in biology and ecology!
• Natural selection of hereditary traits (DNA)
  differential selection and reproduction over time
• Adaptation traits acquired through natural
  selection that fit an organism to its environment
• Speciation the creation of new species through
  the process of natural selection

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What causes species to become threatened,
endangered, or extinct?

• Habitat loss,
• fragmentation, degradation

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• Hunting, poaching, overfishing
• Extermination
• Global climate change
• Non-native species

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Non-native Invaders

• Next to habitat loss, the greatest cause of
  species extinction
• Pimentel, et al. (1999) say
• US has 50,000 non-indigenous species
• Losses added up to gt138 Billion/year
• 42 of ESA listed species at risk primarily due
  to non-native invasive species
• Number of threatened
• species even higher in other
• parts of the world

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Human population and global impact
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What are we losing?

• 70 of bird species declining 1 in 6 threatened
  with extinction
• 2003 World Conservation Union red list,
  http//www.iucn.org/ 12,259 species worldwide
  are Critically Endangered, Endangered or
  Vulnerable
• In California, 672 Special Animals currently
  listed http//www.dfg.ca.gov/whdab/html/animals.ht
  ml

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Rare, Threatened, Endangered and Animal Species
of Special Concern in California

• California Tiger Salamander Ambystoma
  californiense

• 672 Special Animals currently listed
• Lists and information Biological Information -
  Animals.htm
• http//www.dfg.ca.gov/whdab/html/animals.html
• http//www.dfg.ca.gov/whdab/html/cawildlife.html

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California CondorGymnogyps californianus
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Rare Invertebrates in California

• Inverts in general
• shrimp, crayfish, snails, butterflies, beetles,
• grasshoppers and one fly
• Bay Checkerspot Butterfly
• Euphydryas editha bayensis
• Mt Hermon June Beetle
• Polyphylla barbata

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Rare, Threatened, Endangered and other Special
Status Plants

• Special Status Plants
• 1,519 plant genotypes are rare or extinct in
  California alone
• http//www.dfg.ca.gov/whdab/html/plants.html
• California Native Plant Society
• http//www.cnps.org/

Narrow-leaf Spineflower Chorizanthe angustifolia
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Species need Ecosystems

• We can focus on species, but ultimately we need
  to preserve their habitats, which are parts of
  ecosystems
• Rare ecosystems rare species
• Must sustain
• species AND
• ecosystems

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Ecosystems in Danger

• Endangered ecosystems coral reefs, wetlands,
  grasslands, ancient forests (tropical, temperate)
• Globally Destroyed 20-50 of rainforests, 80 of
  temperate deciduous forests
• California 90 of wetlands, 99 grasslands
• Altered 50-80 of the earths land surface

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Biodiversity Hotspots

• High diversity areas, threatened by human
  activity
• Coastal areas, Islands, Tropical and
  Mediterranean climates

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Why are Biodiversity Hotspots so important?

• 34 hotspots on only 2.3 of earths surface
• 75 of worlds most threatened vertebrates
• Information www.biodiversityhotspots.org

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Why care about Ecosystems?

• Natural Capital Ecosystem Services 16
  trillion to 54 trillion/year
• more information www.esa.org/science/Issues/
• The earths ecosystems sustain our economies and
  our lives.
• They must be used sustainablymeeting the needs
  of current generations without compromising the
  needs of future generations

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But what about extinctions of species we have not
named?

• During the next thirty years, most biologists
  believe that as many as 20 of species alive
  today will become extinct,
• Some estimate that as many as 50 of all species
  on the Earth will die out in that time.

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Why care about species loss?

• Economic or Medical uses
• Scientific and Ecological reasons
• Aesthetics and Recreation
• Ethical reasons--Extinction is forever

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• Our children will never be able to enjoy the
  species and ecosystems we are destroying

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What can we do?

• Reduce, reuse, recycle

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• Limit our
• environmental footprint

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• Work for equitable distribution of wealth and
  education globally

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• Help preserve land and resources locally and
  internationally

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Solutions

• Laws such as the Endangered Species Act
• Zoos, captive breeding and reintroduction
• Refuges, national parks, sanctuaries

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Thats all, for now!
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Why should humans care?Biodiversity loss

• Impairs the environment's ability to recover from
  natural and human-induced disasters

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• 2. Destroys natural systems that purify the
  world's air and water

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• 3. Reduces potential to discover new medicines

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• 4. Increases flooding, drought, and other
  environmental disasters

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• 5. Degrades the world's economies
• weakening the social and political stability of
  nations across the globe