Chapter 22 Sustaining Wild Species

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Chapter 22 Sustaining Wild Species

• Biodiversity chapter by Miller Living in the
  Environment

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How could the most common bird in America become
extinct in only a few decades?

• What happened? How?
• What could have been done differently?

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Factors that increase diversity

• A physically diverse habitat
• moderate environmental disturbance
• Some middle stages of succession
• Small variations in
• Nutrient supply
• Precipitation
• Temperature
• evolution

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Factors that decrease biodiversity

• Environmental stress (list them)
• Large environmental disturbance
• Alien species
• Geographic isolation (fragmentation)
• Extreme conditions
• Severe limitation of
• Essential nutrient
• Habitat

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Humans have taken

• 40-50 of land surface of earth
• Use, waste, destroy 27 of total or 40 of
  terrestrial net primary productivity
• Caused global extinction rate 100-1000 times
  natural background
• World Conservation Union-34 of fish(51
  freshwater), 25 amphibians,20 reptiles,14
  plants, 12 birds are threatened with extinction
• 539 recorded extinctions since 1600

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Biodiversity in the US?

• 21 000 species- 33 threatened
• 95-98 of old growth has been cut (lower 48)
• Southeastern longleaf forest
• Tallgrass prairie
• Calif native grassland, wetlands, redwoods
• Hawaii dryforest, grassland, rainforest
• Fish communities nationwide
• Current wetlands loss in US, counting rules have
  changed

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Species extinction rates based on

• Island biogeography (MacArthur and Wilson)
• Species diversity versus latitude
• Stat. sampling in rainforests
• Earths total of species?
• Rate of tropical forest clearance
• Loss of 1000-75 000/year or 3-200/day

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Precautionary strategies

• Chapters 23 24

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What are the three types of species extinctions?

• Local extinction
• Ecological extinction
• Biological extinction
• Local population extinction?

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What are T E species?

• Species heading toward biological extinction
• Endangered species
• So few survive, probable extinction soon
• Threatened species
• Numbers declining, could soon be endangered

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Rare Species

• Naturally small numbers
• Limited geography
• Low population density
• Locally depleted by human activity
• Could be vulnerable to extinction

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Species - Area Curve

• Meaning?
• How does this influence extinction estimates?
• 90 loss 50 loss in species

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Biodiversity Protection

• Species approach
• Goal- prevent extinction of that species
• Strategy- ID(monitor)protect critical habitat
• Tactics- legally protect, captive breeding,
  reintroduce to habitat
• Ecosystem approach
• Goal- protect habitats with species
• Strategy- preserve sufficient areas
• Tactics-purchase,stop aliens,protect natives,
  restore degraded ecosystems

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Population Viability Analysis

• Statistical risk assessment
• Trends in pop. Size
• Changes in habitat
• Changed in genetic variability
• Minimum Viable Population
• Number necessary for pop to survive 100 years
• (50-500 rule for genetic variability)
• Most in 1000s for stochastic events

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Loss of genetic diversity

• Founder effect
• Inbreeding depression
• Demographic bottleneck
• Genetic drift

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Minimum Dynamic Areas

• Suitable habitat
• Home ranges
• Colonies or metapopulations
• Availability of nearby populations

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Mass extinction vs.. Background extinction

• Background-
• 3-14/yr if 14 million species
• 1-5 /yr if 5 million
• Mass- catastrophic, widespread, 25 to 70 and
  even 95 have been lost.
• Followed by Adaptive Radiation

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Why do most biologists think there is a new mass
extinction crisis?

• The earth is 1000 times above the background
  extinction rate.

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How many mass extinctions?

• Ordovician-Silurian boundary
• End of Devonian
• End of Permian
• Triassic-Jurassic Boundary
• Cretaceous-Tertiary Boundary (K-T)

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Causes of Premature Extinctions?

• Human pop growth
• Economics that dont value ecological services
• Greater per capita resource use
• Increasing appropriation of net primary
  productivity
• Poverty (and wealth)

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Habitat loss, fragmentation, degradation vs.
species loss

• Deforestation
• Coral reefs and wetlands
• Plowing grasslands
• Pollution of freshwater

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• Climate change and migration
• Trees
• Animals without a habitat?

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Islands and Fragmentation

• Endemic species
• Extinction rates on islands
• Decrease in sustainable pop size
• Increased edge effect
• Susceptibility to invaders(non-natives)
• Susceptibility to stochastic events
• Barriers to dispersal

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What harm are non-natives?

• New Guinea Brown Tree Snake on Guam
• Crayfish in the Santa Monica Mtns
• Kudzu
• Brazilian Pepper Tree in Florida (its here, too)
• Fire ants

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CITES

• What is this acronym?
• What about elephants?
• Whales?
• Tigers?
• Rhinoceros?

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Predators and Pest Control?

• Carolina Parakeet
• Elephants
• Coyotes
• Wolves
• Prairie dogs (black footed ferrets)

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Exotic Pets and Plants

• 50 die for each sold.
• 60 bird species are T or E -(pet trade)
• Ecotourism more profitable than imports
• Cyanide and coral reefs
• Orchids and cactus

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What do we do?

• Bioinformatics
• International treaties CBD, CITES
• National Laws ESA 1973(USFWS,NMFS)
• Private landowners and the ESA
• National Association of Homebuilders
• Force out endangered species by plowing,
  planting, clearing, burning
• Habitat conservation plans
• Safe harbor agreements
• Candidate conservation agreements

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Endangered Species Act weakened

• voluntary protection?
• Govt pay landowners?
• Harder to list new T/E species?
• Interior Secretary(appointed)to allow extinction?
• Secretary to give exemptions?
• Prohibit public comment or lawsuits?

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Can we save them all?Limited funds(

• Best chances for survival?
• Most ecological value?
• Potentially useful? Medicines, products
• Keystone roles?
• Tolerant to environmental change?

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Saving Species until after the demographic
transition.

• Seed banks( cool, low humidity)
• Gene banks
• Botanical gardens
• Butterfly farming
• Zoos game parks for later reintroductions
• Egg pulling and captive breeding
• Other techniques
• Artificial insemination
• Surgical implantation
• Incubators
• Cross fostering
• Zoo DNA prevent inbreeding depression
• Genetic cloning

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What is wildlife management?

• Manipulates wildlife populations and their
  habitats for human benefit.
• Regulates hunting
• Management plans
• Improving habitat
• Protects migrating game species

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Veg. and Water manipulations for wildlife
management?

• Disturb habitats to favor desired species
• Early successional species
• mid-successional species
• Late successional species
• Wilderness species
• Which are lesser snow geese?

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Was that enough?