Sustaining Biodiversity:

1
Chapter 12

• Sustaining Biodiversity
• The Species Approach

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Key Concepts

• Human effects on biodiversity
• Importance of biodiversity
• How human activities affect wildlife
• Management of wildlife

3
67 Secure or apparently secure
US Diversity
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What Increases Biodiversity?

• Physically diverse habitat
• Moderate environmental disturbance
• Small variations in conditions
• Middle stages of ecological succession

5
What Decreases Biodiversity?

• Environmental stress
• Large environmental disturbance
• Extreme environmental conditions
• Severe limiting factors
• Introduction of alien (exotic) species
• Geographic isolation

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60
EUROPE
NORTH AMERICA
ASIA
30N
Tropic of Cancer
Atlantic Ocean
AFRICA
Pacific Ocean
Pacific Ocean
150
90
60E
0
30W
90
120
150
0
SOUTH AMERICA
Indian Ocean
Tropic of Capricorn
AUSTRALIA
30S
Antarctic Circle
60
ANTARCTICA
Critical and endangered
Threatened
Stable or intact
Projected Status of Biodiversity 19982018
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Strategies for Protecting Species
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Species Extinction

• Local Extinction when a species is no longer
  found in the area that it once inhabited (but is
  still found elsewhere in the world)
• Ecological Extinction so few members of a
  species are left that it cant play its
  ecological role
• Biological Extinction species is not found
  anywhere on earth (permanent)

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Endangered and Threatened Species

• Endangered Species so few survivors that the
  species could soon become extinct
• Threatened Species still abundant in its natural
  range but is likely to become endangered due to
  declining numbers

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Extinction Risks

• Low reproductive rate (K-strategists) blue
  whale, giant panda
• Specialized niche giant panda
• Narrow distribution island species
• Feeds at high trophic level Bengal tiger, bald
  eagle
• Rare island species, orchids
• Commercially valuable elephant

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How Do We Estimate Extinction Risks?

• Population viability analysis (PVA) risk
  assessment to predict whether a population will
  persist for a certain of generations
• PVA is based on resource needs, current and
  predicted habitat conditions, genetic
  variability, interactions with other species,
  reproductive rates

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Continued

• Minimum viable population (MVP) smallest number
  of individuals necessary for the survival of a
  population in a region
• Minimum dynamic area (MDA) the minimum area of
  habitat needed to maintain the MVP

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Why Should We Care About Biodiversity?

• Humans value nature in different ways
• Instrumental value usefulness to us
• Intrinsic value because they exist, regardless
  of use
• Utilitarian (use) goods, services, recreation
• Nonutilitarian (nonuse) aesthetic

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Value of Nature
Instrumental
Intrinsic
(human centered)
(species or ecosystem centered)
Utilitarian
Nonutilitarian
Existence
Goods
Ecological services
Aesthetic
Information
Recreation
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Causes of Depletion of Wild Species

• Human population growth
• Failure to value the environment
• Increasing resource use
• Poverty

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Habitat loss
Habitat degradation
Overfishing
Basic Causes
Introducing nonnative species
Climate change

• Population growth
• Rising resource use
• No environmental accounting
• Poverty

Commercial hunting
Pollution
Sale of exotic pets and decorative plants
Predator and pest control
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Type of Nonnative Organism
Annual Losses and Damages
Crop disease
23.5 billion
Crop weeds
23.4 billion
Rats
19 billion
Feral cats and outdoor pet cats
17 billion
Crop insects
14 billion
Livestock diseases
9 billion
Forest insects and diseases
4.8 billion
Zebra mussels
3 billion
Common pigeon
1.1 billion
Formosan termite
1.1 billion
Damage from Nonnative Species
Fishes
1.1 billion
Asian clam
1.1 billion
Feral pigs
0.8 billion
Starlings
0.8 billion
Fire ant
0.6 billion
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Characteristics of Successful Invader Species
Characteristics of Ecosystems Vulnerable to
Invader Species

• High reproductive rate, short generation time
  (r-selected species)
• Pioneer species
• Long lived
• High dispersal rate
• Release growth- inhibiting chemicals into soil
• Generalists
• High genetic variability

• Similar climate to habitat of invader
• Absence of predators on invading species
• Early successional species
• Low diversity of native species
• Absence of fire
• Disturbed by human activities

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What Can Be Done to Reduce Threat from Nonnative
Species?

• Identify characteristics that make species
  successful invaders and use this information to
  screen out invaders
• Increase inspections of goods coming into a
  country
• Pass laws to ban the transfer of harmful invader
  species

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Biome
of Area Disturbed
Temperate broadleaf forests
94
Temperate evergreen forests
94
Temperate grasslands
72
Mixed mountain systems
71
Tropical dry forests
70
Subtropical and temperate rain forests
67
Cold deserts and semideserts
55
Mixed island systems
53
Warm deserts and semideserts
44
Habitat Disturbance by Biome
Tropical humid forests
37
Tropical grasslands
26
Temperate boreal forests
18
Tundra
0.7
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Hunting and Poaching
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Wild African Elephant

• 1970 2.5 million
• Today 300,000
• Killed for tusks (worth about 500-1500)
• Bleed to death
• 1989 ban on sale of ivory from elephants
• Caused increased killing of walruses and hippos
  for ivory

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Protecting Wild Species I

• Bioinformatics managing, analyzing, and
  communicating biological information
• Involves 1. building computer databases 2.
  developing computer tools to analyze the
  information 3. communicating the information
• Example Species 2000- global research project
  with the goal of providing information about all
  species on earth

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Protecting Wild Species II

• International Treaties
• Convention on International Trade in Endangered
  Species (CITES) 1972
• Signed by 152 countries
• Lists 900 species that cannot be commercially
  traded
• Restricts international trade of 29,000 other
  at-risk species

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Protecting Wild Species III

• National Laws
• Lacey Act of 1900 prohibits transportation of
  live or dead animals (or their parts) across
  state borders without a permit
• Endangered Species Act of 1973 illegal for
  Americans to import or trade any product made
  from an endangered or threatened species

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Protecting Wild Species IV

• Habitat Conservation Plans
• Compromise between endangered species and private
  landowners
• Landowners are allowed to kill a certain of
  endangered species on private land in exchange
  for taking steps to protect the species
• Possible steps setting aside a preserve for the
  species, paying to relocate the species, paying
  for government buy habitat elsewhere

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Other Approaches to Protecting Wild Species

• Wildlife refuges and protected areas
• Gene banks (storing plant seeds), botanical
  gardens (cultivation of rare and endangered
  plants), and farms (raise for commercial sale)
• Zoos and aquariums

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Wildlife Management

• Laws regulating hunting and fishing
• Harvest quotas
• Population management plans
• Improving habitat
• Laws for migrating species