Download Understanding Our Environment

Biodiversity
Chapter 13
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Outline:
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Biodiversity and Species Definitions
Benefits of Biodiversity
Threats to Biodiversity
 Human Caused Reductions
Biodiversity Protection
 ESA
- Minimum Viable Populations
 CITES
Captive Breeding
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
BIODIVERSITY AND SPECIES
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Biodiversity Types:
 Genetic Diversity - Measures variety of
different versions of same genes.
 Species Diversity - Measures number of
different kinds of organisms within a
community.
 Ecological Diversity - Measures richness
and complexity of a community.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
What Are Species
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Species - Organisms of the same kind that
are able to breed in nature and produce
fertile offspring.
 Underlying idea is that reproductive
isolation prevents gene exchange and
gives rise to new species.
- Hybridization creates a dilemma.
 Species identification often based on
morphological characteristics.
 DNA sequencing
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
How Many Species
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Currently 1.4 million species identified.
Estimates range between 3-50 million.
 May be 30 million insect species.
 May be 10 million species on ocean floor.
 Invertebrates make up 70% of all known
species, and probably most of yet to be
discovered species.
Tropical rainforests and coral reefs are
biodiversity hotspots.
 NA and Europe only contain 10-15%.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
BENEFITS OF BIODIVERSITY
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Food
 As many as 80,000 edible wild plant
species could be utilized by humans.
Drugs and Medicines
 More than half of all prescriptions contain
some natural product.
 Pharmaceutical companies actively
prospect tropical countries for products.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Benefits of Biodiversity
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Ecological Benefits
 Soil formation, waste disposal, air and
water purification, nutrient cycling, solar
energy absorption, and biogeochemical
and hydrological cycles all depend on
biodiversity.
- Can a system function without all its
integral parts ?
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Benefits of Biodiversity
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Aesthetic and Cultural Benefits
 Cultural diversity inextricably linked to
biodiversity.
 USFWS estimates Americans spend $104
billion annually on wildlife-related
recreation.
 Ecotourism can be an important form of
sustainable economic development.
 Existence (intrinsic) value.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
THREATS TO BIODIVERSITY
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Extinction - Elimination of a species.
 Normal process
- In undisturbed ecosystems, background
rate appears to be one species per
decade.
 In this century, human impacts have
accelerated that rate, causing perhaps
hundreds to thousands of extinctions
annually.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Natural Causes of Extinction
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Fossil Record suggests more than 99% of all
species ever in existence are now extinct.
 Most went extinct before humans arrived.
- End of Cretaceous - Dinosaurs and 50%
of existing genera disappeared.
- Permian period - Two-thirds of all marine
species and nearly half of all plant and
animal families died out.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Human-Caused Reductions in Biodiversity
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Habitat Destruction
 Biggest reason for current increase in
extinction is habitat loss.
- Habitat fragmentation divides
populations into isolated groups
vulnerable to catastrophic events.
Hunting and Fishing
 Over-harvesting of game species.
- American Passenger Pigeon
- Whales
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Habitat Fragmentation - Cadiz Township, WI
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Human-Caused Reductions in Biodiversity
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Commercial Products and Live Specimens
 Wildlife smuggling is very profitable.
- Leopard fur / Rhinoceros horns
 US Annual pet trade in wild species:
 2 million reptiles
 1 million amphibians and mammals
 500,000 birds
 128,000 tropical fish (often caught
with cyanide above coral reefs)
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Predator and Pest Control
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Many animal populations have been greatly
reduced or exterminated because they are
regarded as dangerous to humans or
livestock.
 Animal control costs $20 million in federal
and state funds annually.
- 700,000 birds and mammals annually.
 100,000 coyotes
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Predator and Pest Control
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Exotic Species Introductions
 Exotic organisms - Organisms introduced
into habitats where they are not native.
- Biological Pollution
 Kudzu Vine
 Purple Loosestrife
 Zebra Mussels
 Asian Long-Horned Beetles
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Predator and Pest Control
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Diseases
 When a disease is introduced into a new
environment, natural balance may be
tipped, leading to an epidemic.
Pollution
 Toxic Pollutants
- Pesticides
- Lead
Genetic Assimilation
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
BIODIVERSITY PROTECTION
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Hunting and Fishing Laws
 By 1890’s, most states had enacted some
hunting and fishing laws.
 General idea was pragmatic, not aesthetic
or moral preservation.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Endangered Species Act
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Established in 1973.
 Endangered are those considered in
imminent danger of extinction.
 Threatened are those likely to become
endangered, at least locally, in the near
future.
- Vulnerable are those that are naturally
rare or have been locally depleted to a
level that puts them at risk.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Endangered Species Act
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ESA regulates a wide range of activities
involving Endangered Species:
 Taking (harassing, harming, pursuing,
hunting, shooting, killing, capturing, or
collecting) either accidentally, or on
purpose.
 Selling
 Importing into or Exporting out of the US
 Possessing
 Transporting or Shipping
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Endangered Species Act
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Currently, US has 1,500 species on its
Endangered and Threatened lists, and about
500 candidate species waiting for
consideration.
 Number reflects more about human
interests than actual status.
- Invertebrates make up 75% of all
species, but only 9% of T/E list.
 Listing process is extremely slow.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Recovery Plans
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Once a species is listed, USFWS is required
to propose a recovery plan detailing the
rebuilding of the species to sustainable
levels.
 Total cost of all current plans = $5 billion.
Opponents have continually tried to require
economic costs and benefits be incorporated
into planning.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Private Land and Critical Habitat
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Eighty percent of habitat for more than half of
all listed species is on non-public property.
 Supreme Court has ruled destroying
habitat equates to taking.
- USFWS has been negotiating Habitat
Conservation Plans (HCP) with private
landowners.
 Landowners allowed to harvest
resources as long as species benefit.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Reauthorizing ESA
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ESA officially expired in 1992.
 Proposals for new ESA generally fall into
two general categories:
- Versions that encourage ecosystem and
habitat protection rather than individual
species.
- Safe Harbor policies that allow exceptions
to critical habitat designations.
 (Economic Considerations)
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Minimum Viable Populations
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Minimum Viable Population is the minimum
population size required for long-term
viability of a species.
 Island biogeography - Small islands far
from a mainland have fewer terrestrial
species than larger, closer islands.
- MacArthur and Wilson proposed that
species diversity is a balance between
colonization and extinction rates.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Minimum Viable Populations
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Diversity Loss in Small Populations:
 Founder Effect
- Few individuals start a new population.
 Demographic Bottleneck
- Few individuals survive catastrophe.
 Genetic Drift
- Random reduction in gene frequency.
 Inbreeding
- Mating between related individuals.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Habitat Protection
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Latest management strategy is preservation
of ecosystems supporting maximum
biological diversity rather than species-byspecies approach.
 Gap Analysis - Conservationists and
wildlife managers look for unprotected
landscapes that are rich in species.
- Broad-scale, holistic approach.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Biodiversity Map
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
International Wildlife Treaties
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Convention on International Trade In
Endangered Species (CITES) - 1975.
 Regulated trade in living specimens and
products derived from listed species.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
CAPTIVE BREEDING
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Breeding programs in zoos and botanical
gardens are one method of saving
threatened species.
 Repositories of genetic diversity.
- Most mammals in NA zoos are now
produced from captive-breeding
programs.
 Some zoos now participating in
reintroduction programs.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Captive Breeding
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Zoos have limited space for captive breeding.
 How many can / should we save ?
 Ultimate problem is that natural habitat may
disappear while we are conserving the
species itself.
Another alternative is to attempt to save
species in the wild.
 Provide funding for protection in native
habitats.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Summary:
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Biodiversity and Species Definitions
Benefits of Biodiversity
Threats to Biodiversity
 Human Caused Reductions
Biodiversity Protection
 ESA
- Minimum Viable Populations
 CITES
Captive Breeding
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.