Download File

Ch. 18
Part 4
Importance of Biodiversity
Threats to Biodiversity
1. Habitat loss and degradation
of environment
2. Climate change
3. Excessive use of fertilizers
and industrial/domestic
forms of pollution
4. Overexploitation and
unsustainable use of
resources
5. Effects of Invasive
species/Alien Species on
native species
– endemics
Habitat Loss
• Destruction of the natural
environment
– Deforestation large impact on
biodiversity
• Slash and burn
• Decrease biodiversity for crops and
ranching (low biodiversity)
– Monocultures
• Leads to severe land degradation as a
result of SOIL EROSION once plants
are removed
–
–
–
–
–
–
Removal of vegetation for:
Agriculture
Housing
Transport
Leisure activities
Industrial
– Habitat Fragmentation  habitats
of plants and animals divided into
smaller areas
• Fishing
Overexploitation
– Difficult to know if fish stocks
are sustainable
– Overfishing  extinction
– Fisheries with
declining/collapsing populations
of fish
• Grand Banks, North Atlantic 
cod
• North Sea  herring
• East China sea  Variety of
Species
– Steep decrease in predatory fish
 increasing fishing of smaller
fish/lower on food chain
• Affects marine mammal
populations that depend on
smaller fish for food
• Logging
– Removing trees faster than they
can be regenerated
– Teak & Mahogany
Loss of Single Species affecting
Community
• Sea otters, kelp, and sea urchins
Loss of Sea Otter
(Enhydra lutris)
• Catastrophic loss of many
other species (sea kelp)
• Sea otter  central role
in maintaining ecosystem
(keystone species)
• Placed on endangered
species list numbers
increased
• Currently hunted by killer
whale
– Killer whales food
supply is down because
of overfishing
Examples of Keystone Species
• Euhydra
lutris (sea
otter)
• Loxodonta
Africana
(bush
elephant)
Pollution
• Industrial and domestic waste
– Attempts to reduce impact on
environment
• Sewage  treated before it reaches aquatic
ecosystems
– Not prevalent around the world
• Pollution consists of chemicals that animals
bodies cannot metabolize or excrete
– Polychlorinated Biphenyls (PCBs)
» Waste from manufacturing processes
» Not treated before released into
environment
» Enters food chains  biological
magnification
» Weakens immune systems & fertility in
organisms
– Plastics in Oceans
» Non-biodegradable
» Bags, nets
Fertilizers
• Areas affected farmlands
(low-lying land near coast)
• Unabsorbed fertilizer (not
taken in by crops) become
runoff into lakes, rivers, and
streams  ocean
• Extra nutrients  excessive
growth of producers (algae)
EUTROPHICATION
– Occurs faster than feeding rate
of herbivores that consume
them
– Algae produces toxic
substances that affect other
organisms in ecosystem
– Unbalanced food web
– Excessive algae growth
DECREASES biodiversity
• Affects terrestrial and
aquatic ecosystems
• Sulfur Dioxide in
atmosphere bad
– Formed by
combustion of fuel
with high sulfur
content (coal)
– Sulfur Dioxide + water
vapor in atmosphere =
acid rain
• Destroys vegetation
• Acidification of
aquatic ecosystems
downwind of
industrial area
• Few animals can
survive/bred in low
pH water
• Biodiversity
decreased
Air Pollution
Climate Change
• Caused by build up of green house
gasses in atmosphere
• Increase in carbon dioxide and
methane (green house gases)in
atmosphere due to:
• Industrialization
• Extraction and combustion of fossil
fuels
• Excess methane
– Cattle ranching
– Rice farming
– Anaerobic breakdown of waste at
land fills
• Global warming  produces
changes in distribution of
terrestrial ecosystems
–
–
–
–
–
Migration patterns
Acidification of oceans
Temperature changes in oceans
Sea levels rising
Frequency of natural catastrophes
Climate Change
• Migration patterns
– North/south to cooler climates
– Excess competition with decreasing # of cooler areas
• Acidification of oceans
– Affects organisms that rely on calcium carbonate for shells and skeletons
• Temperature changes in oceans
– Symbiotic relationship disrupted f temp remains to high
– Organisms leave coral  coral bleaching occurs  death of coral  decrease
biodiversity  less protection for coastline ecosystems
• Sea levels rising
– Affect productive coastal ecosystems
– Range of ecosystems restricted
– Fragmentation occurs
• Frequency of natural catastrophes
– Natural disasters increase
– Example:
– Following natural disasters (typhoons and hurricanes) is flooding of coastal ecosystems
•
•
•
•
•
•
Excess nutrients in coastal waters
Increase phytoplankton growth
Excess food for larvae of star fish
Adult starfish eat coral
Normally coral runs our and starfish population deceases and coral regrows every ten years
More frequent disasters  coral unable to catch up  biodiversity reduced -> ecosystem destroyed
Importance of Biodiversity
1. Moral & Ethical Reasons
– Humans have responsibility
2. Ecological Reasons
– Higher diversity = less chances of
being disputed by changes in
environmental conditions (natural
or man made)
– Ecosystems high value to humans
– Drugs (antibiotics)
– Example: Madagascan periwinkle &
Pacific Yew Tree  drug paclitaxel Taxol
– Plants provide high value to humans
3. Aesthetic Reasons
– Ecotourism  important to
economies
– Sense of pleasure
Importance of Biodiversity
4.
Social & Commercial Reasons
– Crop plants low genetic diversity
– Wild plants/variants  source of genetic
variation and diversity
– Provide important alleles that can be
introduced by interbreeding with crop
plants & gene technology
– Microorganisms as a producer of
enzymes important in medicine
• Some of these only exist in certain
ecosystems
5.
Other services
– Absorption of carbon dioxide (forests and
bogs)
– Break down of organic waster in water
(by microorganisms)
– Transpiration of water by plants  fresh
water for humans
– Recycling of matter (termites, ants, fungi,
bacteria)
• Supply nitrates, phosphates, and sulfates to
soil for plant growth (effects entire food
chain, all trophic levels)
Protecting Endangered Species
• Endangered species species
that is threatened with
extinction
• Variety of protection methods
– Best: keep species in natural
habitat
• All life support systems provided
• High profile conservation
programs
– Focus on large mammals
• Protection of entire ecosystems
important
– Tropical rainforest
– Karst limestone
National Parks
• Areas of land controlled by government
of a country and protected by
legislation
• Government sets aside areas of land
where wildlife and environment are
protected
• Human activities limited
–
–
–
–
–
–
Limits on building
Grazing of animals
Hunting
Agriculture
Mining
Industrial activities
• Act as conservation areas of wild life
Yellowstone National Park
• 1st national Park,
USA, 1872
– Last remaining,
intact ecosystem of
the northern
climatic zone
– Conservation &
recreational area
– Home to threatened
and endangered
animals
Galapagos Islands
•
•
•
•
•
•
•
•
•
Ecuador
Est. 50years ago
Conservation park
Restricted access to uninhabited
islands
Limited access to areas sensitive
to human interference
Marine reserve of 133 000 km2
set up to protect environment
from fishing
Alien Animal species removed
Invasive plants removed
Captive breeding and
reintroduction programs
coordinated by the Charles
Darwin Research Station
National Parks and Awareness
• Restrictions on human activities
• Tourism important
– Money finds maintenance of
parks & education about
conservation
– Increases awareness of important
issues
– Public can help
– Involvement of local people
important
• Allowing them to use certain areas
of the park
• Employing locals
• Use money from parks to improve
healthcare facilities and educational
facilities
Marine Parks
• Set up to conserve
fragile ecosystems at
risk of:
– Overfishing
– Dredging
– Pollution
• Improving biodiversity
can improve fish
catching as well
• Marine reserve off
coast of Little Cayman
– Protects spawning
ground of endangered
fish, Epinephelus
striatus (Nassau
grouper)
International Conservation Areas
• Ramsar sites
– Wetlands considered to be
important in conservation of
wildlife
• Estuaries, salt marshes,
blanket bogs, ponds,
mangroves
• High biodiversity
– Designated under treaty
signed by Ramsar in Iran in
1971
• States that designated areas
must be used wisely
• Gives protection against
building development and
extraction of minerals
Management of Parks and Reserves
• Vary from area to area
– Some countries have
resources while others do not
• Government support
• Money
• Threats remain great
– Some species removed from
natural areas and placed
somewhere safer
Zoos
• Protection for endangered
and vulnerable species
• Successful captive
breeding programmes
– Goal is reintroduction to
native habitat
• Important role in research
1. Gaining better
understanding of
breeding habitats
2. Habitat requirements
3. Increasing genetic
diversity
Captive Breeding Programmes
• Goal: Reintroduce animals
to natural habitat
– Difficult
• Many factors affect success
• Successful breeding
programs:
– Blue-and –Gold Macaw Ara
ararauna
– Scimitar-horned oryx Oryx
dammah
Problems with Captive Breeding Programmes
• Inbreeding
• Low genetic diversity
• Aim of captive breeding
programmes is to maintain genetic
diversity
– Females mate with different males
– Example: Cheetah
• Refusal of animals to breed in
captivity
• Difficulty of returning to wild and
surviving after being cared for
– Do not acquire natural skills in
captivity
– Example: pandas and golden lion
tamarins
Assisted Reproduction
• Solution to problem of
inbreeding
– Transport of large animals
between zoos (captive
breeding programs)
• Difficult
• Expensive
• Breeding not guaranteed
• Problem males and females
do not show courtship
behavior
• Alternate Option  Sperm
Banks
• Less expensive
• Sperm samples from males
collected, checked for activity,
diluted with medium and
albumen; stored in thin tubes
called straws and kept in liquid
nitrogen
Methods of Assisted Reproduction
• Artificial Insemination (AI)
– Straw placed in warm water to
activate sperm
– Straw placed into catheter that has
been placed into female reproductive
organs (to reach uterus) when female
is in “heat” (ovulating)
• Hormone treatment needed sometimes
 superovulation = large # of follicles
• Embryo transfer occurs (following
AI)
– embryos removed (flushed out) of
uterus & transferred to female who
has had pregnancy hormone
treatment (surrogate mother)
• Same species not required
– Reason: protects endangered animal
from risks of pregnancy  used for
more offspring
Methods of Assisted Reproduction
• In vitro Fertilization (IVF)
– Oocytes collected
• Needle is inserted into ovaries
• Mature follicles extracted
• Oocytes kept in culture medium for short
time
• Oocytes mixed with semen
• Zygotes form
– Divide into embryos
• Embryos cultured for several days
• Embryos placed back into mother OR several
females of different species
– Ooocyte & Embryo storage
• Similar to sperm
• More difficult
– Damage likely with freezing/thawing process
» Eggs are large cells with large water
component
» Water inside egg forms ice crystals 
damage internal membranes of cell
– Eggs fertilized in vitro THEN frozen until
surrogate mother is available
Frozen Zoos
• Holds genetic resources
in form of:
– Sperm
– Eggs
– Embryos
• Genetic info is from
endangered and
vulnerable species
• Can hold more genetic
diversity than a normal
zoo
• Material can be kept for
long periods of time
• Example:
– San Diego Zoo
Problems of Successful Conservation
• Organism saved from extinction BUT numbers
are TOO HIGH beyond carrying capacity that
ecosystem can support
• Culling
– Practice of taking something out of the breeding
population
• Birth control
– neutering/spaying
» Vasectomy (cutting of sperm duct)
– Female chemical contraceptives (non-steroid hormones)
» Vaccines  targets ZONA PELLUCIDA (region
surrounding layer of glycoproteins around the egg)
• Stimulate immune response to make
antibodies AGAINST the glycoproteins
• Prevent sperm from fertilizing eggs
• 90% success in mammals
• Slaughtering
• Transferring animals to areas with small populations
– Used to reduce numbers of species that have
surpassed sustainable a capacity
– Ethical issues
• Ex.
– 1966-1994 16,000 elephants culled into Kruger Park in
South Africa to limit growth of population
Botanic Gardens
• Protect endangered plants
• Seeds & Cuttings collected from species in wild
– Used to build population in garden
– Can be reintroduced into ecosystem if needed
• Tissue Cultures and Cloning
– Used to produce large # of plants from a few original
specimen
• Small samples of cells collected
• Grown on agar in sterile conditions
• Cells divide by mitosis  mass of cells created and subdivided for
cloning
• Cells transferred to medium with plant hormones
• Cells grow into stems and roots
• Transferred in soil to grow
• Reintroduce plants into natural habitats
– Fairchild tropical Gardens (MIAMI!)
• Sargents Cherry Palm  Florida Keys
• Seed Banks
– Collect and store seeds from many diverse plants in case
extinction occurs
– Seeds from same species collected from different sites to
ensure good proportion from total gene pool
– Prevents loss of genetic diversity of our crop plants
Roles of Botanic Gardens
• Protection of endangered species
– Botanic gardens currently cultivate 1/3 of
world’s known plant species that have been
threatened by:
• Environmental degradation
• Climate change
• Research methods of reproduction and
growth
– Species cultivated in gardens can be grown
in appropriate conditions and propagated
• Research conservation methods
– Enable plants to be reintroduced to new
habitats if original is destroyed
• Reintroduce species to habitats where they
have become rare/extinct
• Educate public
– Role of plants in ecosystems and economy
• Millennium Seed Bank
Seed Banks
– The Royal Botanic Gardens at Kew, UK,
2000
– Goal: collect and store seeds from at
least 25% of world’s plants by 2025
– Seeds arrive at seed bank and are
checked for pests, diseases, viability,
dried, and stored in airtight jars
• Svalbard Global Seed Vault
– Run by government of Norway, started
2008
– Located in Arctic Circle (end of 120m
tunnel in side of mountain)
• Ideal storage conditions (-18*C)
• 2013  over 770,000 seed samples
from crops around world
– Stores seeds in case there is loss of
seeds in a seed bank (duplicate
samples kept here)
– Seed banks can deposit seeds here and
still own rights to those seeds
– Applications to use seeds must be filed
– Storage of seeds is free
Seed Banks
• International Rice Institute
– Philippines
– Hold all rice varieties
• International Cocoa
Genebank
– Trinidad
– Has 12,000 cocoa trees
banked
– Distributed to cocoa
producing countries after
inspection by University of
Reading in UK
Storage of Seeds
• Orthodox seeds
– Seeds that remain viable for 15+
years
– Dehydrated to only 5% water
– Stored at -15* to -20*C
– Little ice crystallization = little
chance seeds are damaged
• Recalcitrant seeds
– Seeds that cannot be dehydrated
and frozen
– Economically important tropical
species
• Rubber, coconut palm, coffee, cocoa
– Only way to maintain genetic
diversity:
• Collect seeds and grow many
generations
• Tissue cultures
Issues with Growing Samples from Stored Seeds
• Possibility of altering
genetic diversity
• Problem in small samples of
seed from rare plants
– Smaller samples of original
are taken to test for viability
or to grow into plants to
increase number of seeds in
store
– Samples unlikely to contain
all genetic diversity in original
sample
– Solution:
• Put as large and diverse a
sample as possible into storage
•
•
Controlling Alien Species
Alien/invasive species:
– Species moved from one ecosystem to another where they were
previously unknown
– Moved due to:
• Humans
– Global trading of plants and animals
– Unknown transport on ships
– Biological control agents (Pest control)
– Introduced for sport
– Released and/or escaped pets
Problems with invasive species:
– Prey on native species
– Outcompete native species for resources
• Food and space
• Can lead to extinction of native species
– Introduce new pathogens/diseases to native species that have never
been exposed to them
– Toxic to native species
– No natural predators to keep population balanced
– Overcrowd/overgrow in areas to prevent resources from reaching
native organisms
– Damage human health
– Damage structures
Examples of Alien Species
•
Indian mongoose, Herpestes auropunctatus
– Introduced to Jamaica in 1872 to control rats in cane
fields (successfully)
– Began to prey on native species
•
Cane toad
– Introduced to Queensland, Australia in 1935 to control
insect pest of sugar cane
– Breeds rapidly and became a pest itself
– Spread across country
– Produces toxin that kills animals
– Endangered marsupial carnivore (northern quolle,
Dasyurus hallucatus) close to extinction
– Compete with other amphibians for resources
– Prey on chicks of native birds
•
Burmese pythons
– Introduced to Florida Everglades probably by reluctant
pet owners who could no longer care for it
– Feed on mammals and birds so it became competition
for native predators
– Humans are the only predator
•
Rabbits
– Introduced in Australia for sport in 19th century
– Caused the most loss of biodiversity
Examples of Alien
Species
• Red lionfish, Pterois volitans
– Introduced to Caribbean waters
– Destroys local coral reefs
– Hunting expeditions encouraged and cuisines
featuring lion fish being introduced
• Water hyacinth, Eichhornia crassipes
– Floating aquatic plant that spreads rapidly
– Covers entire surface of water
– Blocks sunlight so native aquatic plants
cannot grow
– Leads to reduced oxygen concentration =
dead native fish
– Habitat for mosquito larvae = vectors for
disease  effects human health
• Japanese knotweed, Fallopia japonica
– Vigorous root system
– Forces its way up through side walks, roads
– Damages structures (concrete buildings,
roads, walls)Outcompetes native species for
space
International Conservation Organizations
• CITES
– Convention on International
Trade in endangered
Species of Wild Flora and
Fauna
• Agreement est. in 1973 by
145 countries to control the
trade of endangered species
and any products from them
• Created an appendices
regarding endangered
species
• Negative aspect  desire for
organisms on list make them
more desirable and increase
poaching/hunting
International Conservation Organizations
• WWF
– World Wide Fund for Nature
– Best known campaigning groups
for wild life, est. 1961 by NGOs
(non-governmental
organization)
– Mission Statement:
• “To stop the degradation of the
planets natural environment and
to build a future in which humans
live in harmony with nature”
• Goals/asks:
– Fund conservation projects
– Publicizes environmental issues
– Campaigns to save ecosystems from
degradation
– Campaigns to save species from
extinction
Restoration of Degraded Habitats
• Important to restore areas degraded by
human activity OR natural disasters
– Large scale or small scale
• Example
– Mangrove forests
• Rich ecosystem
• Provides protection for coastline from
storms
• At risk due to coastal development
• Provide Ecosystem services
– Reduce coastal erosion
» Reduce effects of strong waves
during storms
– Barrier to rising sea levels
» Trap sediment
– Nurseries for young fish
• Replanting Mangrove project in
Sunderbans Delta Region
– 26,000 sq. km, India and Bangladesh
– Largest mangrove forest n the world
– Offers land protection against rising sea
levels