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					The Benefits of Healthy Ecosystems

    Ecosystem services are the benefits people obtain from ecosystems. Many of
     the services listed here are interlinked.
    Provisioning Services. These are the products obtained from ecosystems,
          Food. This includes the vast range of food products derived from plants, animals, and
          Fibre. Materials such as wood, jute, cotton, hemp, silk, and wool.
          Fuel. Wood and other biological materials serve as sources of energy.
          Genetic resources. This includes the genes and genetic information used for animal
           and plant breeding and biotechnology.
          Biochemicals, natural medicines, and pharmaceuticals. Many medicines and food
           additives such as alginates, and biological materials are derived from ecosystems.
          Ornamental resources. Animal and plant products, such as skins, shells and flowers
           are used as ornaments and whole plants are used for landscaping and ornaments.
          Freshwater. Freshwater in rivers is also a source of energy. Because water is required
           for other life to exist, it could also be considered a supporting service.

2008 Fall Lecture 5                       SCIE 103 Life Sciences                                1
The Benefits of Healthy Ecosystems

    Regulating Services. These are the benefits obtained from the regulation of
     ecosystem processes, including:
          Air quality regulation. Ecosystems both contribute chemicals to and extract chemicals
           from the atmosphere, influencing many aspects of air quality;
          Climate regulation. Ecosystems influence climate both locally and globally. Changes
           in land cover can affect both temperature and precipitation.
          Water regulation. The timing and amount of runoff, flooding, and aquifer recharge can
           be strongly influenced by changes in land cover.
          Erosion regulation. Vegetation plays an important role in soil retention and the
           prevention of landslides.
          Water purification and waste treatment. Ecosystems can help to filter out and
           decompose organic wastes introduced into inland waters and coastal ecosystems.
          Disease regulation. Changes in ecosystems can directly change the abundance of
           human disease.
          Pest regulation. Ecosystem changes affect the frequency of crop and livestock pests
           and diseases.
          Pollination. Ecosystem changes affect the distribution, abundance, and effectiveness
           of pollinators.

2008 Fall Lecture 5                       SCIE 103 Life Sciences                               2
The Benefits of Healthy Ecosystems
    Cultural Services. These are the non-material benefits people obtain from
     ecosystems through spiritual enrichment, reflection, recreation, and aesthetic
     experiences, including:
          Cultural diversity. The diversity of ecosystems is one factor influencing the diversity of
          Spiritual and religious values. Many religions attach spiritual and religious values to
           ecosystems or their components.
          Knowledge systems (traditional and formal). Ecosystems influence the types of
           knowledge systems developed by different cultures.
          Educational values. Ecosystems and their components and processes provide the
           basis for both formal and informal education in many societies.
          Inspiration. Ecosystems provide a rich source of inspiration for art, national symbols,
           architecture, and advertising.
           Aesthetic values. Many people find beauty or aesthetic value in ecosystems, as reflected
           in the support for parks, scenic drives, and the selection of housing locations.
          Social relations. Ecosystems influence the types of social relations that are established
           in particular cultures.
          Sense of place. Many people value the "sense of place" that is associated with
           recognized features of their environment.
          Cultural heritage values. Many societies place high value on the maintenance of either
           historically important landscapes ("cultural landscapes") or culturally significant species.
          Recreation and ecotourism. People often choose where to spend their leisure time
           based in part on the characteristics of the natural or cultivated landscapes in a particular

2008 Fall Lecture 5                         SCIE 103 Life Sciences                                  3
The Benefits of Healthy Ecosystems

    Supporting Services. Supporting services are those that are
     necessary for the production of all other ecosystem services. They
     differ from provisioning, regulating, and cultural services in that their
     impacts on people are often indirect or occur over a very long time.
          Soil Formation. Because many provisioning services depend on soil fertility,
           the rate of soil formation influences human well-being in many ways.
          Photosynthesis. Photosynthesis produces oxygen necessary for most living
          Primary Production. The assimilation or accumulation of energy and
           nutrients by organisms.
          Nutrient cycling. Approximately 20 nutrients essential for life, including
           nitrogen and phosphorus, cycle through ecosystems and are maintained at
           different concentrations in different parts of ecosystems.
          Water cycling. Water cycles through ecosystems and is essential for living

2008 Fall Lecture 5                   SCIE 103 Life Sciences                          4
        Ecosystem Service           Ecosystem Functions                       Examples
Gas regulation                 Regulation of atmospheric           CO2/O2 balance, O3 for UVB
                               chemical composition                protection, SOx levels.
Climate regulation             Regulation of global                Greenhouse gas regulation.
                               temperature, precipitation and
                               other climatic processes
Disturbance regulation         Storage, damping and other          Storm protection, flood control,
                               responses to environmental          drought recovery and other
                               fluctuations                        habitat responses, mainly
                                                                   controlled by vegetation
                                                                   structure and landforms.
Water regulation               Regulation of hydrological flows.   Water for agriculture, industry,
                                                                   transportation or power
Water supply                   Storage and retention of water      Storage of water in watersheds,
                                                                   reservoirs and aquifers.
Erosion control and sediment   Retention of soil within an         Prevention of soil loss by wind,
retention                      ecosystem.                          runoff or other processes,
                                                                   storage of silt in lakes and
Soil formation                 Soil formation processes.           Weathering of rock and the
                                                                   accumulation of organic
Nutrient cycling               Storage, internal cycling,          Nitrogen Fixation, N, P and other
                               processing and acquisition of       elemental or nutrient cycles.

2008 Fall Lecture 5                    SCIE 103 Life Sciences                                         5
        Ecosystem Service        Ecosystem Functions                     Examples
Waste treatment             Recovery of nutrients and        Waste treatment, pollution
                            removal or breakdown of excess   control, detoxification.
                            nutrients and compounds.

Pollination                 Fertilization of flowers.        Providing pollinators for the
                                                             reproduction of plant
Biological control          Population regulation.           Predator control; reduction of

Refugio                     Habitat for resident and         Nurseries, migration habitat,
                            transient populations.           over wintering grounds.

Food production             Production useable as food.      Fish, game, crops, nuts and
Raw materials               Production useable as raw        Lumber, fuel, fodder.
Genetic resources           Sources of unique biological     Medicine, products for materials
                            materials and products.          science, resistant genes/strains,
                                                             ornamental species.
Recreation                  Opportunities for recreational   Eco-tourism, sport fishing,
                            activities.                      hunting, hiking, camping.

Cultural                    Non-commercial uses.             Aesthetic, artistic, educational,
                                                             spiritual, scientific.

2008 Fall Lecture 5                 SCIE 103 Life Sciences                                       6
Threats to biodiversity
    In part because the value of biodiversity and the resulting ecosystem services
     are poorly understood by a lot of people, nature's ―cogs and wheels‖ are going
     missing at an alarming rate — on the order of 100 to 1000 times the background
     rate, estimated from fossil records to be from one to ten species/year (Pimm, et
     al., 1995 and others). Some estimates of current rates are much higher. There
     have been five mass extinctions in the past 500 million years, the most recent
     about 65 million years ago (Raup and Sepkoski, 1982). We appear to be in the
     sixth, with the major difference being that for this one, the cause appears to be
     not a major physical catastrophe such as severe volcanism or a meteor strike,
     but a single species: us.
    The Millennium Ecosystem Assessment (2005) reports that there has been a
     substantial and largely irreversible loss in the earth's biodiversity, with some 10-
     30% of mammal, bird and amphibian species currently threatened with
     extinction, and 15 of 24 ecosystem services being degraded. Fortunately, it
     comes at a time when the earth probably contains more species than ever
     before (Rhode and Muller, 2005), and there's some redundancy built into the
     system. We can lose some species — some — before things start to really

2008 Fall Lecture 5                   SCIE 103 Life Sciences                            7
Threats to biodiversity

    The causes of these losses
     are varied and can be
     encompassed in the term
          Habitat loss: Habitat loss,
           alteration and fragmentation
           directly affect the species
           that rely on the habitat that
           is being changed.

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Threats to Biodiversity – Habitat Destruction

    Habitat destruction – single greatest threat to

2008 Fall Lecture 5       SCIE 103 Life Sciences       9
Deforestation of tropical forests

2008 Fall Lecture 5   SCIE 103 Life Sciences   10
Deforestation Closer to Home

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Threats to Biodiversity – Habitat Destruction

    Fragmentation of a forest ecosystem

2008 Fall Lecture 5     SCIE 103 Life Sciences   12
Threats to Biodiversity
     The history of habitat reduction and fragmentation in a Wisconsin

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Threats to Biodiversity – Habitat Destruction

    Tropical forests house between 50 and 90 percent of species live
     on earth. About 17 million hectares of tropical forests – an area
     four times the size of Switzerland – are now being cleared
     annually, and scientists estimate that at these rates roughly 5 to
     10 percent of tropical forest species may face extinction within
     the next 30 years.
    Rates of tropic forest loss are accelerating, and some particularly
     species-rich forests are likely to be largely destroyed in our
     lifetime. Some scientists believe that about 60,000 of the world's
     240,000 plant species, and perhaps even higher proportions of
     vertebrata and insect species, could lose their lease on life over
     the next three decades unless deforestation is slowed

2008 Fall Lecture 5            SCIE 103 Life Sciences                 14
Threats to Biodiversity – Habitat Destruction

    Tropical forests are by no means the only sites with endangered
     biodiversity. Worldwide, nearly as much temperate rainforest – once
     covering an area nearly the size of Malaysia – has also been lost.
     Although the total extent of forest in the northern temperate and boreal
     regions has not changed much in recent years, in many areas the
     species-rich, old-growth forests have been steadily replaced by second-
     growth forests and plantations. Evidence of accelerating clearance of
     temperate forests is also appearing: between 1977 and 1987, 1.6
     million hectares of forest was lost in the United States alone.
    In several spots in Europe, fungal species diversity has dropped by 50
     percent or more over the past 60 years. In such "Mediterranean"
     climates as California, South Africa, central Chile, and Southwest
     Australia, at least 10 percent of all plant and animal species are
     imperiled. The largest number of recent extinctions has been on
     oceanic islands: some 60 percent of plant species endemic to the
     Galapagos Islands are endangered, as are 42 percent of the Azores'
     endemic species and 75 percent of the endemic plant species of the
     Canary Islands.

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Threats to biodiversity
    The causes of these losses are varied
     and can be encompassed in the term
          Invasive (Introduced) species:
           Invasive species are harmful non-
           native species whose introduction or
           spread threatens the environment, the
           economy and society, including human
           health. Invasive species originate from
           other continents, adjacent countries or
           from other ecosystems within Canada.
           Free from predation and competition
           that would normally limit their                          emerald ash borer
           distribution and abundance in their
           natural habitats, many invasive species
           reproduce rapidly and damage,
           displace or destroy native species in
           our forests (e.g., emerald ash
           borer), agricultural areas (e.g., plum
           pox virus), wetlands (e.g., purple
           loosestrife) and lakes and rivers (e.g.,
           zebra mussel). The zebra mussel
           disrupts ecosystem composition and
           structure, clogs water intake pipes, and
           affects public beaches.                           plum pox virus       zebra mussel

2008 Fall Lecture 5                        SCIE 103 Life Sciences                                16
Threats to Biodiversity – Introduced Species
    Introduced Species
          Ranking second to habitat loss as a cause of biodiversity crisis
          Species that humans move from the species’ native locations to
           new geographic regions.
          Of all 1,880 imperiled species in the United States, 49% are
           endangered because of introduced species alone or because of
           their impact combined with other forces.
          Introduced species are a greater threat to native biodiversity than
           pollution, harvest, and disease combined.
          Through damage to agriculture, forestry, fisheries, and other
           human enterprises, introduced species inflict an enormous
           economic cost, estimated at $137 billion per year to the U.S.
           economy alone.
          Some introduced species (such as most of our food crops and
           pets) are beneficial. However, others are very damaging.

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Threats to Biodiversity – Introduced Species

    The Asian chestnut blight fungus
     virtually eliminated American chestnut
     from over 180 million acres of eastern
     United States forests in the first half of
     the 20th century. It was a disaster for
     many animals that were highly
     adapted to live in forests dominated by
     this tree species. For example, ten
     moth species that could live only on
     chestnut trees became extinct.
    The Australian paperbark tree has
     replaced native plants, such as
     sawgrass, over 400,000 acres of south
     Florida, because it has a combination
     of traits (for example, spongy outer
     bark and flammable leaves and litter)
     that increase fire frequency and
     intensity. Many birds and mammals
     adapted to the native plant community
     declined in abundance as paperbark

2008 Fall Lecture 5                      SCIE 103 Life Sciences   18
Threats to Biodiversity – Introduced Species

    Pump house and water control
     structure for green-tree
     impoundment at Montezuma
     National Wildlife Refuge in central
     New York. Waterfowl broods
     produced in adjacent flooded forest
     found excellent foraging conditions
     among floating and emergent
     aquatic plants in the foreground, 18
     June 1968.
    Ten years later, purple loosestrife
     had displaced native food and cover
     plants in the waterway surrounding
     the green-tree impoundment at the
     Montezuma Refuge. Biologist
     holding stadia rod in middle
     foreground is obscured by mature
     plants. Note the abundance of
     Lythrum salicaria seedlings along
     the water line, 16 August 1978.

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Threats to Biodiversity – Introduced Species
    Zebra mussels (Dreissena polymorpha) are
     small, fingernail-sized mussels native to the
     Caspian Sea region of Asia. They are
     believed to have been transported to the
     Great Lakes via ballast water from a
     transoceanic vessel. The ballast water,
     taken on in a freshwater European port was
     subsequently discharged into Lake St. Clair,
     near Detroit, where the mussel was
     discovered in 1988. Since that time, they
     have spread rapidly to all of the Great Lakes
     and waterways in many states, as well as
     Ontario and Quebec.
     Diving ducks and freshwater drum eat zebra
     mussels, but will not significantly control
     Likely means of spread: Microscopic larvae
     may be carried in livewells or bilgewater.
     Adults can attach to boats or boating
     equipment that is in the water.

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Threats to Biodiversity – Introduced Species

    Nile perch (Lates niloticus),
     a voracious predator
     introduced to Lake Victoria
     as a food fish, has already
     extinguished over one
     hundred species of native
     cichlid fish there.
    The introduction of Nile
     perch into Australia was
     considered after a reduction
     in Queensland barramundi
     stocks, but this was decided
     against due to the
     devestation they caused in
     several African lakes.

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Threats to Biodiversity – Introduced Species

    A parasite can be
     similarly devastating.
     The sea lamprey
     reached the Great
     Lakes through a series
     of canals and, in
     combination with
     overfishing, led to the
     extinction of three
     endemic fishes.

2008 Fall Lecture 5      SCIE 103 Life Sciences   22
Threats to Biodiversity – Introduced Species
    Scientific name: Boiga irregularis
    Common name: Brown tree snake
    Native To: Australia
    Date of U.S. Introduction: First
     detected in Guam in the 1950s,
     introduced in cargo from the Admiralty
    Means of Introduction: Arrived in
     Guam accidentally in imported cargo
    Impact: Preys on native lizards and
     birds, has eliminated ten of the eleven
     native bird species from the forests of
     Guam; causes frequent power outages
     by climbing on electrical wires
    Current U.S. Distribution: Guam

2008 Fall Lecture 5                SCIE 103 Life Sciences   23
Threats to Biodiversity – Introduced Species
   The first Argentine ants set foot on U.S. soils in
    the late 1890's, as coffee ships from Brazil
    unloaded their cargo in New Orleans. Being
    prolific breeders and constantly on the go, they
    moved across the southern half of the United
    States. A single colony may contain 10,000
    female workers, and there may be hundreds of
    colonies around your home; the total number of
    ants could easily reach a million. Although they
    cannot sting, they can bite; however, they are
    only about 3 mm long and there tiny mandibles
    are too small to hurt humans. But, in the world
    of insects, these ants are truly a living terror.
    They are very aggressive and readily overtake
    other ant species, even ants that are much
    larger and with powerful stings. Argentine ants
    are relentless and simply outnumber their
    adversaries until the enemy colony is destroyed.
    They even attack paper wasp nests under the
    eaves of a house, forcing the huge wasps to
    flee their nests in terror. Even nests of large
    carpenter bees are no match for these
    relentless ants. A "killer bee" nest probably
    could not withstand an invasion of Argentine
    ants. They also will attack bird nests, driving off
    the mother bird and killing the helpless young.
    One possible redeeming quality about these
    little warriors is that they may attack dry-wood
    (aerial) termite colonies in your home.

2008 Fall Lecture 5                          SCIE 103 Life Sciences   24
Threats to Biodiversity – Introduced Species

    Beauty can be a trap, and
     despite the appeal of the
     Caulerpa taxifolia with its
     lovely green flowers, this
     invasive species represents
     a great danger for neritic                      Caulerpa taxifolia
     Mediterranean habitats.
     These algae preferentially
     invade posidonia prairies,
     impoverishing the already
     threatened marine flora and

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Threats to Biodiversity – Introduced Species
     Some impacts of invaders are subtle but nonetheless
     destructive to native species:
    North American gray squirrels are driving native red squirrels to
     extinction in Great Britain and Italy by foraging for nuts more
     efficiently than the native species. Such competition for
     resources is not easy to observe, but the end result is the loss of
     a native species.
    Hybridization, or cross-breeding, of introduced species with
     natives is an even subtler impact (no lineage goes extinct), but it
     is insidious because it leads gradually to the extinction of many
     native species, as their gene pools inevitably evolve to become
     those of the invader. Introduced mallards, for instance, are
     driving the native Hawaiian duck to a sort of genetic extinction by
     breeding with them.
    Of 26 animal species that have gone extinct since being listed
     under the Endangered Species Act, at least three were wholly or
     partly lost because of hybridization with invaders. One was a fish
     native to Texas, eliminated by hybridization with introduced
     mosquito fish.

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Threats to Biodiversity – Introduced Species
    Rainbow trout introduced widely in
     the United States as game fish are
     hybridizing with five species listed
     under the Endangered Species Act,
     such as the Gila trout and Apache
    The endangered, endemic Hawaiian
     duck is being lost to hybridization
     with North American mallards                      white-headed duck
     introduced for hunting.
    The rarest European duck (the
     white-headed duck) is threatened by
     hybridization with the North
     American ruddy duck, which was
     originally kept as an amenity in a
     British game park. The ruddy duck
     escaped, crossed the English                          ruddy duck

2008 Fall Lecture 5           SCIE 103 Life Sciences                       27
Threats to Biodiversity – Introduced Species

    Often invaders interact with one another to generate a problem
     where either species alone would be harmless. For example,
     ornamental fig trees in the Miami area for over a century stayed
     where planted, in people's yards, because they were sterile.
     Each fig species requires a particular wasp to pollinate it, and the
     wasps were absent. About fifteen years ago, the pollinating
     wasps for three fig species arrived independently in the region,
     and now these fig species are reproducing. At least one has
     become invasive, with seedlings and saplings being found many
     miles from any planted figs. More cases of this phenomenon,
     termed "invasion meltdown," are likely to arise as more species
     are introduced and have the opportunity to interact with each

2008 Fall Lecture 5            SCIE 103 Life Sciences                  28
Threats to biodiversity
    The causes of these losses are varied and can be encompassed in the term
          Pollution: Pollution is emitted in many different forms, including atmospheric pollution, soil and
           water pollution, pesticides, particulate matter, and heavy metals. There are thousands of
           pollutants circulating through the Earth's ecosystems, and many of these materials have
           significant, large-scale impacts on forests and aquatic ecosystems. Acid precipitation, for
           example, has had a significant impact on Ontario's maple forests and industrial pollutants such
           as DDT is known to have caused significant declines in populations of many bird species
           including Peregrine Falcon and Bald Eagles. Pollution can also disrupt ecological processes.
           For example, scientists are now linking light pollution to declines in migratory songbirds.
          Population growth: Human population growth adds to the impact of all the other causes
           because more people require more space and more resources. There are now about 6 billion
           people on Earth, more than twice as many as in 1950. While the rate of increase is slowing, it
           still adds more than 90 million people each year. Habitats, even healthy ones, can support just
           so many of anything, including people.
          Over-consumption or unsustainable use: Over-consumption is the harvest of species at a
           rate higher than can be sustained by the natural reproduction of the population. In Ontario, for
           example, wild American ginseng has been over-harvested from its natural rich woodland habitat
           to the point of being Endangered.
          Climate Change and other Cumulative impacts: People have added carbon dioxide, nitrous
           oxide, methane and other greenhouse gases to the atmosphere by extracting and burning fossil
           fuels such as coal, oil and natural gas. The effect of these gases has been to trap heat and
           accelerate the rate of global warming and climate change. Climate change is a major threat to
           the world's biodiversity. The cumulative impacts of pollution, habitat modification, the global
           redistribution of species and over-harvesting place many ecosystems at risk. These cumulative
           impacts cause alteration, reduction and loss of ecosystem function, populations and species,
           degradation, loss and fragmentation of habitat. They also damage human health.

2008 Fall Lecture 5                           SCIE 103 Life Sciences                                     29
Threats to Biodiversity - Overconsumption

    Refers generally to the human harvesting of
     wild plants and animals at rates exceeding
     the ability of the populations of those species
     to regenerate.
    Logging, hunting and fishing
    Especially susceptible are large species with
     low intrinsic reproductive rates.
    Eg. Elephants, whales, rhinoceroses, and
     species on small islands.
2008 Fall Lecture 5    SCIE 103 Life Sciences      30
Threats to Biodiversity - Overconsumption
    A new global study concludes that
     90 percent of all large fishes have
     disappeared from the world's
     oceans in the past half century,
     the devastating result of industrial
    The study, which took 10 years to
     complete and was published in the
     international journal Nature, paints
     a grim picture of the Earth's
     current populations of such
     species as sharks, swordfish, tuna
     and marlin.
    The authors used data going back
     47 years from nine oceanic and
     four continental shelf systems,
     ranging from the tropics to the
     Antarctic. Whether off the coast of
     Newfoundland, Canada, or in the
     Gulf of Thailand, the findings were
     dire, according to the authors.

2008 Fall Lecture 5                 SCIE 103 Life Sciences   31
Threats to Biodiversity - Overconsumption

2008 Fall Lecture 5   SCIE 103 Life Sciences   32
Threats to Biodiversity - Overconsumption

2008 Fall Lecture 5   SCIE 103 Life Sciences   33
Reducing the threats to biodiversity
    The global response to HIPPOC has been the promotion of sustainable
     development, defined by the OBS as “development that meets the needs of the
     present without compromising the ability of future generations to meet their own
    But what does that mean, in a practical sense? One way is to link biodiversity to
     sustainable development through the concept of “sustainable use: the use of
     components of biodiversity in a way and at a rate that does not lead to their
     long-term decline, thereby maintaining the potential for future generations to
     meet their needs and aspirations” (OBS, 2005). We don't want to lose species
     because it will eventually degrade our natural capital, and any reduction in
     ecological services is a sure sign that biodiversity is eroding.
    The loss of a single species is not ―the end of the world as we know it,‖ but
     cumulatively it may be. Losing species destabilizes ecosystems and weakens
     their ability to deal with natural disasters such as floods, droughts and fire and
     with human-caused stresses such as pollution and climate change. The
     precautionary principle states, when in doubt do no harm. In this case, stopping
     all species loss where possible is probably the best rule of thumb.

                            Blue-Ringed Dancer (Argia sedula)

2008 Fall Lecture 5                      SCIE 103 Life Sciences                      34
What can you do to help?
    Learn more. Knowledge is power. The more we know about the causes, consequences
     and how to prevention of biodiversity loss, the more power we will have to act. Also, our
     actions will be more efficient and focused.
    Tell others. As we learn more about biodiversity, we need to let others know as well that
     biodiversity conservation is worth pursuing. We can discuss it among groups we belong to.
     We can write letters or emails to editors and others of influence.
    Help monitor biodiversity. Citizen science, the monitoring of species and ecosystems by
     individuals and groups, is growing across the world. It's a good way to involve people who
     already have an interest and perhaps knowledge of nature. Learn more and make a
    Get organized. Work is ongoing on many of the Action Items. If you belong to
     organizations that should be involved, contact that group, encourage involvement and offer
     to help.
    Reduce our Ecological Footprints. We all do things every day which directly or indirectly
     affect biodiversity by putting pressure on our natural systems. Reduce such pressure by:
          Being aware of Species at Risk and taking action to protect their populations or habitat.
          Being knowledgeable of Invasive Species, and acting to limit their spread.
          Creating habitat for wild things on your property - planting butterfly or wildflower gardens with
           native plants and trees, maintaining brush piles, or participating in a local habitat restoration
          Avoiding pesticides, herbicides and chemical fertilizers.
          Buying locally grown food whenever possible.
          Reducing energy use in homes, businesses and institutions and vehicles.
    Influence politicians. Let politicians at all levels know that biodiversity conservation is a
     critical issue that the government needs to do more about.

2008 Fall Lecture 5                            SCIE 103 Life Sciences                                      35
What is a "Species at Risk?"
    A species at risk is any native plant or animal that is at risk of
     extinction or of disappearing from its natural environment.
    ―Endangered species‖ – one that is in danger of extinction
     throughout all or a significant portion of its range.
    ―Threatened species‖ – those that are likely to become endangered
     in the foreseeable future throughout all or a significant portion of
     their range.

 Region               Mammals   Birds   Reptiles     Amphibians     Fishes   Mollusks   Other Inverts   Plants   Total

 Turkey                 18       15       13              9             54      0            12           3      124

2008 Fall Lecture 5                            SCIE 103 Life Sciences                                                    36
Threats to Biodiversity
    The Great Auk is an extinct flightless bird that has become a symbol of
     destruction of the Earth and its life forms. The last authenticated sighting of
     this species was from Fire Island off the coast of Cape Reykjanes, Iceland,
     on June 3, 1844. At that time a pair of adult Great Auks were caught and
     killed by collectors. The adults had laid an egg and were incubating. That
     was probably the last egg ever laid of this species. Great Auk specimens
     soon came to rest in major collections and museums in Europe and North
     America. This was largely due to bequests of private collections, integration
     of collections into one facility and purchases of collections from estates.
     One of Canada's few specimens, at the Royal Ontario Museum, arrived
     there from such a purchase.

2008 Fall Lecture 5                 SCIE 103 Life Sciences                         37
Threats to Biodiversity
    Greater mouse-eared
     bat (Myotis myotis)
          The greater mouse-eared bat
           is one of the larger European
           bats and has become extinct in
           England. Its fur is a medium-
           brown colour on the upper
           body, and greyish-white
           underneath. It has large ears
           with a very prominent tragus,
           the organ which is part of the
           bat’s echolocation system.
          Status: Classified as Extinct
           in the UK. Listed under
           Appendix II of the Bonn
           Convention, Annex II of the
           Berne Convention, Annex II &
           IV of the EC Habitats Directive
           and Schedule 5 of the Wildlife
           and Countryside Act (as

2008 Fall Lecture 5                  SCIE 103 Life Sciences   38
A hundred beats from extinction: Most
Endangered Species of 2007
    The western lowland gorilla (Gorilla
     gorilla gorilla) is one of many new
     additions to the World Conservation
     Union (IUCN)'s 2007 Red List of
     Threatened Species, which was made
     public today. Since 2006, the annual
     assessment of the planet's imperiled
     wildlife has grown by more than a
     thousand species and now totals 41,415.
    Many great apes end up on the list, as
     their habitat is continually under threat
     from human activities.
    Western lowland gorilla populations in
     central Africa have collapsed due to the
     commercial bush meat trade and the
     Ebola virus. And in Indonesia,
     orangutans are critically endangered
     because of forest logging and clearing
     land for palm oil plantations. (National
     Geographic Sept. 12, 2007)

2008 Fall Lecture 5                     SCIE 103 Life Sciences   39
    A hundred beats from extinction: Most
    Endangered Species of 2007
     The baiji (Lipotes vexillifer), or Chinese
      river dolphin— deemed "functionally
      extinct" by a team of scientists in
      December—was downgraded from
      "endangered" to "critically endangered
      (possibly extinct)" on the IUCN's 2007
      Red List.
     Populations of the light blue-gray animal,
      which lives in China's polluted Yangtze
      River, have plummeted over the last 30
     A possible sighting in August 2007 is
      currently being investigated by Chinese
      scientists, but even if one or two dolphins
      are found, the baiji is almost certainly
     ―Freshwater dolphins are very
      vulnerable, because rivers tend to be
      heavily used by humans and there is
      nowhere else for the dolphins to go,‖
      Caroline Pollock, a Red List program
      officer, told National Geographic News.

    2008 Fall Lecture 5                    SCIE 103 Life Sciences   40
A hundred beats from extinction: Most
Endangered Species of 2007
    The Egyptian vulture, a new
     addition to IUCN's 2007 Red List,
     has declined along with many
     other vulture species. Five species
     of vulture, including the Egyptian,
     have been reclassified to a higher
     threat level since 2006. Asian
     vultures have declined rapidly
     over the last eight years due to the
     use of a livestock drug called
    African vultures are struggling due
     to habitat loss, a lack of food, and
     collisions with power lines.
    The scavengers are also being
     killed by insecticide-laden
     carcasses, which have been
     deliberately baited to poison
     livestock predators such as

2008 Fall Lecture 5                 SCIE 103 Life Sciences   41
A hundred beats from extinction: Most
Endangered Species of 2007
    Mexico’s Santa Catalina Island
     rattlesnake has been classified as
     critically endangered on the 2007
     IUCN Red List. The snake, found on
     just one island, sports highly desirable
     patterned skin that has made it a
     collector's item for hunters.
    New reptile surveys are revealing the
     fragile nature of many reptile
    For instance, a major survey of North
     American reptiles has bumped up the
     region's Red List reptile species to a
     total of 738.
    The main culprit behind their decline is
     habitat loss due to expanding cities,
     Caroline Pollock, a Red List program
     officer, told National Geographic
    ―Unlike birds and mammals, we
     haven't assessed all the reptiles on the
     planet,‖ Pollock added.

2008 Fall Lecture 5                    SCIE 103 Life Sciences   42
    A hundred beats from extinction: Most
    Endangered Species of 2007
      The Banggai cardinal fish's popularity as
       a pet for the home aquarium has landed
       it on the 2007 IUCN Red List. In the
       wild, the striped fish is only found in the
       Banggai Archipelago off Indonesia.
      Human pressures such as the aquarium
       trade are the main reason for the fish's
       decline, with habitat loss and climate
       change also posing major threats.
      Fish stocks are in free-fall all over the
       world, both from overfishing and the
       aquarium trade. Scientists estimate
       current extinction rates are at least a
       hundred to a thousand times higher
       than natural rates.
      ―We need to protect the world's
       biodiversity in order to ensure a
       sustainable future for all of us,‖ Caroline
       Pollock, a Red List program officer, told
       National Geographic News.

    2008 Fall Lecture 5                     SCIE 103 Life Sciences   43
A hundred beats from extinction: Most
Endangered Species of 2007
    Reptiles such as the gharial
     are becoming more prominent
     on the IUCN's Red List each
     year. Despite its fearsome
     appearance and lengths of up
     to 19 feet (6 meters), the
     Indian gharial is not a man-
     eater and prefers to eat fish.
    Its long, thin snout, which
     makes it easily distinguishable
     from a crocodile, also allows it
     to quickly capture fish.
    Habitat loss and poaching is
     driving the animal toward

2008 Fall Lecture 5              SCIE 103 Life Sciences   44
A hundred beats from extinction: Most
Endangered Species of 2007
    For the first time, corals were added to
     the 2007 Red List. A recent scientific
     survey on the Galápagos Archipelago
     has added ten corals to the list, including
     the Floreana coral.
    In the 1980s, frequent El Niño weather
     patterns—which made ocean
     temperatures fluctuate—likely led to the
     poor state of the Galápagos corals.
    Some scientists worry that global
     warming may make El Niño events more
     regular and prevent corals from
    Until recently, scientists had not properly
     assessed the health of the world's
     tropical corals. Scientists estimate that
     human activities—such as pollution,
     global warming, and sedimentation—
     could kill 30 percent of reefs in the next
     three decades.
    Coral reefs in the Indian and Pacific
     Ocean, for example, are vanishing faster
     than rain forests.

2008 Fall Lecture 5                       SCIE 103 Life Sciences   45
A hundred beats from extinction: Most
Endangered Species of 2006
    Polar bears and hippos for the first
     time join more than 16,000 species
     threatened with extinction, according
     to the World Conservation Union.
    The Switzerland-based nonprofit,
     known as IUCN, released its 2006 Red
     List of Threatened Species on May 2.
     The list shows a significant increase in
     the number of species on the brink
     since the last list was released in
    The Red List now marks polar bears
     as vulnerable, largely because of
     habitat loss linked to global warming.
     Due to decreasing sea ice in the
     Arctic, "polar bears are predicted to
     suffer more than a 30% population
     decline in the next 45 years," the
     group wrote in a press release.
    The following images highlight other
     Red List species, from pink pigeons to
     blue poison frogs.

2008 Fall Lecture 5                    SCIE 103 Life Sciences   46
A hundred beats from extinction: Most
Endangered Species of 2006
    Manta rays, familiar
     denizens of tropical and
     subtropical ocean-shelf
     waters, are classified
     as near threatened on
     the 2006 IUCN Red
     List. Of the 547 shark
     and ray species
     assessed, the group
     says, 20 percent are in
     danger of extinction.

2008 Fall Lecture 5      SCIE 103 Life Sciences   47
A hundred beats from extinction: Most
Endangered Species of 2006
    Native to the Indian Ocean
     island of Mauritius, the pink
     pigeon has been suffering
     from decades of habitat loss
     and introduction of invasive
     predators. The population
     dropped to a mere 12
     known birds by 1986,
     according to the nonprofit
     Mauritian Wildlife
     Foundation. The bird is now
     listed as endangered on the
     IUCN Red List.

2008 Fall Lecture 5           SCIE 103 Life Sciences   48
A hundred beats from extinction: Most
Endangered Species of 2006
    In addition to land and
     marine animals, the
     IUCN Red List includes
     a number of plants and
     fungi, such as the
     Italian funcia di
     basiliscu. This fungus,
     which grows on the
     island of Sicily, is listed
     as critically

2008 Fall Lecture 5         SCIE 103 Life Sciences   49
A hundred beats from extinction: Most
Endangered Species of 2006
    Amphibian populations in
     Central and South America
     have been declining rapidly,
     a trend that many experts
     link to environmental
     factors. The blue poison
     frog of Suriname, which
     grows up to one and three
     quarters of an inch (four
     and a half centimeters)
     long, is given "vulnerable"
     status on the 2006 IUCN
     Red List.

2008 Fall Lecture 5          SCIE 103 Life Sciences   50
A hundred beats from extinction

    Factors leading to
     mammals' extinction
     continue with "ever
     increasing intensity"
    Siberian tigers may
     vanish within three

2008 Fall Lecture 5          SCIE 103 Life Sciences   51
A hundred beats from extinction
    Lion populations have fallen by
     almost 90% in the past 20
     years, leaving the animal close
     to extinction in Africa. There
     are now only 23,000 left,
     compared to an estimated
     200,000 two decades ago.
    The problem will get worse as
     Kenya's human population
     doubled in the next 12 years.
    The wild dog population has
     fallen to between 3,500 and
     5,000 and there are now fewer
     than 15,000 cheetahs.

2008 Fall Lecture 5            SCIE 103 Life Sciences   52
A hundred beats from extinction

    Orangutans once ranged
     throughout Southeast Asia.
     Today they can be found
     only on the Indonesian
     islands of Borneo and
     Sumatra. Scientists
     estimate that in the last 10
     years their numbers have
     been reduced by up to 50
     percent, to perhaps as few
     as 13,000 living in the wild.

2008 Fall Lecture 5            SCIE 103 Life Sciences   53
A hundred beats from extinction
    Mutisia magnifica: An Ecuadorian
     species threatened by charcoal
    The species most at risk live only in
     small geographic ranges in specific
    The official estimate by the World
     Conservation Union - the IUCN -
     suggests that 13% of the world's
     plant species are under threat, but                   Passiflora loxensis
     the two US botanists say it is at
     least 22% and could be as many as
    They say the IUCN has reliable
     data for plants in Europe, North
     America, South Africa and
     Australia, but there are no reliable
     figures for tropical, developing
     countries, where most of the world's
     plants grow.                                          Mutisia magnifica

2008 Fall Lecture 5               SCIE 103 Life Sciences                         54
Threats to Biodiversity
    The dramatic losses of species and ecosystems obscure equally large
     and important threats to genetic diversity. Worldwide, some 492
     genetically distinct populations of tree species (including some full
     species) are endangered. In the northwestern United States, 159
     genetically distinct populations of ocean-migrating fish are at high or
     moderate risk of extinction, if they have not already slipped into
    Loss of genetic diversity could imperil agriculture. How much the
     genetic base has already eroded is hard to say, but since the 1950s,
     the spread of modern "Green Revolution" varieties of corn, wheat, rice,
     and other crops has rapidly squeezed out native landraces. Modern
     varieties were adopted on 40 percent of Asia's rice farms within 15
     years of their release, and in the Philippines, Indonesia, and some other
     countries, more than 80 percent of all farmers now plant the new
     varieties. In Indonesia, 1500 local rice varieties have become extinct in
     the last 15 years. A recent survey of sites in Kenya with wild coffee
     relatives found that the coffee plants in two of the sites had
     disappeared, three sites were highly threatened, and six were possibly
     threatened. Only two were secure.

2008 Fall Lecture 5              SCIE 103 Life Sciences                     55
Threats to Biodiversity
    The impact of losses of genetic
     diversity often registers swiftly. In
     1991, the genetic similarity of Brazil's
     orange trees opened the way for the
     worst outbreak of citrus canker
     recorded in the country. In 1970, U.S.
     farmers lost $1 billion to a disease
     that swept through uniformly
     susceptible corn varieties.
    Similarly, the Irish potato famine in
     1846, the loss of a large portion of
     the Soviet wheat crop in 1972, and
     the citrus canker outbreak in Florida
     in 1984 all stemmed from reductions
     in genetic diversity. In such countries
     as Bangladesh, where some 62
     percent of rice varieties come from a
     single maternal plant, Indonesia (74
     percent), and Sri Lanka (75 percent),
     such outbreaks could occur at

2008 Fall Lecture 5                SCIE 103 Life Sciences   56
Threats to Biodiversity
    The loss of genetic, species, and ecosystem diversity both stems
     from and invites the loss of cultural diversity. Diverse cultures
     have bred and sustained numerous varieties of crops, livestock,
     and habitats. By the same token, the loss of certain crops, the
     replacement of traditional crops with export crops, the extinction
     of species embedded in religion, mythology, or folklore, and the
     degradation or conversion of homelands are cultural as well as
     biological losses. Since 1900, experts say, about one Indian tribe
     has disappeared from Brazil each year. Almost one half of the
     world's 6000 languages may die out in the next 100 years. Of the
     3000 languages expected to survive for a century, nearly half will
     probably not last much longer.
    Ubık ( Ubykh): Northwestern Caucasian Language. Last spoken
     person Tevfik Esenç died on October 1992.

2008 Fall Lecture 5            SCIE 103 Life Sciences                57
Tevfik Esenç
    Tevfik Esenç (1904 – October 7, 1992) was a Circassian exile in
     Turkey and the last known speaker of the Ubykh language.
     Esenç was raised by his Ubykh-speaking grandparents for a time in the
     village of Hacı Osman köyü in Turkey, and he served a term as the
     muhtar (mayor) of that village, before receiving a post in the civil
     service of Istanbul. There, he was able to do a great deal of work with
     the French linguist Georges Dumézil to help record his language.
     Blessed with an excellent memory, and understanding quickly the goals
     of Dumézil and the other linguists who came to visit him, he was the
     primary source of not only the Ubykh language, but also of the
     mythology, culture and customs of the Ubykh people. He spoke not only
     Ubykh but Turkish and the Hakuchi dialect of Adyghe, allowing some
     comparative work to be done between the two languages. He was a
     purist, and his idiolect of Ubykh is considered by some as the closest
     thing to a standard "literary" Ubykh language that existed.
     Esenç died in 1992 at the age of 88. The inscription that he wanted on
     his gravestone read as follows:
     This is the grave of Tevfik Esenç. He was the last person able to speak
     the language they called Ubykh.

2008 Fall Lecture 5              SCIE 103 Life Sciences                    58
Gaining Biodiversity

    Mutation
     Mutations increase genetic diversity by altering the
     genetic material (almost always DNA) of organisms.
     Once mutations arise, they are passed on to the
     mutated organism's offspring, and in time may either
     disappear if the line dies out. Depending upon the
     specific mutation, the result can range from no effect
     whatsoever to the creation of an entirely new
     species. Although this gives rise to differences in
     organisms, it is an extremely slow process
     compared to the other ways in which local diversity
     increases. Ultimately, though, this is the only way in
     which diversity is truly created.

2008 Fall Lecture 5       SCIE 103 Life Sciences         59
Gaining Biodiversity
    Speciation
     The creation of a new species is known as speciation. Species
     are typically defined as a group of related organisms that share a
     more or less distinctive form and are capable of interbreeding
     and producing fertile offsprings. The origin of new species
     naturally has the largest immediate effect on species-level
     diversity; the immediate changes to genetic and ecosystem
     diversity are usually minimal, though the effects will grow in time.
     Speciation can occur through several different means, including
     geographical isolation, competition, and polyploidy.
          Geographical Isolation: Geographical isolation, such as new
           mountain chains or a lake whose level lowers enough that it splits
           into two separate lakes, can divide a population into two separate
           populations. The two isolated populations continue to evolve
           separately from one another. Eventually they can diverge to a great
           enough degree, either through adaptation to their differing
           environments or through random mutations, that they are no longer
           able to interbreed and are considered to be different species.

2008 Fall Lecture 5                 SCIE 103 Life Sciences                   60
Gaining Biodiversity
    Speciation
          Competition: If a new resource, such as a new food source, becomes
           available to a population, some part of the population may become
           specialized in obtaining that resource. Being specialized in obtaining either
           the new resource or the original resource may be better than trying to obtain
           both. If so, then the specialists would be better off mating with the other
           specialists on the same resource, as mating with someone who uses the
           other resources will result in offspring that aren't specialized for either
           resource and at a disadvantage. In time, there is a chance that the
           population will split into two species, each specialized on one of the two
           resources. This can happen, but it is probably a fairly rare event.
          Polyploidy: Speciation through polyploidy happens far more often in plants
           than in animals, as animals are much more sensitive to large changes in
           their genetic structure. Most species are diploid, meaning they have two
           copies of each chromosome (large packages of DNA), one from each of their
           parents. An individual in a normally diploid species may have more copies of
           these chromosomes, being polyploid ("poly" meaning many), through errors
           at the cellular level. The additional copies of the chromosomes render them
           unable to produce functional offspring with normal members of their species.
           Plants often fertilize themselves to at least some extent, so polyploid species
           can arise from a single individual. This method of speciation is almost
           instantaneous, happening in a single generation, and is more common in
           plants than animals.

2008 Fall Lecture 5                     SCIE 103 Life Sciences                          61
Galapagos Finches

2008 Fall Lecture 5   SCIE 103 Life Sciences   62
Galapagos Finches

2008 Fall Lecture 5   SCIE 103 Life Sciences   63
Gaining Biodiversity
    Immigration
      Immigration increases diversity as new individuals and perhaps
       even new species enter an area, increasing its diversity. The rate
       at which immigration happens depends on the size of the area in
       question, how many species are there already, and how close the
       area in question is to the source of immigration. Even if a species
       is unable to survive in an area, a constant flow of immigrants to
       the area can keep the species present indefinitely. Island
       biogeography is the classic theory on the topic of how these
       factors affect immigration and more, and is explained above.
      Most species that immigrate to a new ecosystem have only minor
       effects on their new system, though some drastically change it.
       Zebra mussels, native to the Caspian Sea and Ural river, were
       first recognized in the Great Lakes in 1988. It is most likely that
       they were brought over in ballast water. Since then they have
       spread throughout the Great Lakes and beyond, killing native
       mussel populations and fouling all manner of pipes and intakes.

2008 Fall Lecture 5             SCIE 103 Life Sciences                  64
Gaining Biodiversity
      Succession
       Succession is the process through which an area gains species as successive
       communities of organisms replace one another until an endpoint is reached. This
       endpoint, or climax community, is commonly a forest. Succession may begin on
       bare rock, an abandoned field, the burned remnants of a forest, or any stage before
       the endpoint. A hypothetical bare field isn't bare for long before annual plants appear.
       They are replaced within a few years by perennial plants and shrubs, who in turn are
       replaced by pine trees. Eventually, hardwood trees invade and replace the pines,
       forming the hardwood climax community.
       Different regions have varying climax communities. One usually refers to the different
       stages of succession in terms of the plants rather than the animals because the
       plants precede the animals and provide the structure and environment that the
       animals live in. One exception to this is aquatic communities, where sponges, corals,
       bivalves and other animals are responsible for much of the three-dimensional
       structure of the community.
       The climax community is typically the most diverse stage of succession, and each
       stage of succession is more diverse than the one preceding it. This pattern depends
       on the group being looked at; plant diversity actually decreases at the final stage,
       while animal diversity increases to the end. Species that were common in the early
       stages of succession will not be common in the later stages, but may still be found if
       small disturbances in the area effectively set the disturbed area back to an earlier
       successional stage.

2008 Fall Lecture 5                     SCIE 103 Life Sciences                              65
    Does Diversity lead to Stability?
    Although it is a key question, the relationship between diversity and stability is still being resolved. As
     with many topics in biodiversity, there are different ways of expressing stability. One way is to define it
     as the ability of a system to return to its original state after being disturbed, so how quickly it can return
     and how large a disturbance it can return from are key variables. Another definition is how resistant to
     change the system is in the first place. No matter what the definition used, however, there are definite
     trends that appear.
    Current consensus is that greater diversity does lead to greater stability, for three general reasons:
         Insurance Effect: Different species do better under different conditions. As the number of species increases, the
          range of conditions that at least some species do well in also increases. When perturbations do occur, it's more
          likely that some of the species present will be able to do well, and these species will protect the community as a
         Averaging Effect: Stability is measured as variability relative to community abundance. As diversity increases, the
          value of the variability will naturally decrease. One problem with this is that the impact of additional species can be
          confused with the effect of larger numbers of individuals (see Doak et al. 1998 and Tilman et al. 1998 for examples
          of this debate).
         Negative Covariance Effect: Since species are competing for resources such as space and food, any gains that
          one species makes will be to some extent at the expense of the other. This means that as a species does more
          poorly its competitors will do better. The result is that disturbances aren't as detrimental to the entire system as they
          could be, as the losses in one species are offset by the gains of another.
    The structure of a food web also affects the stability of the system. Food webs describe the flow of
     energy through the system, basically who eats whom and how often. Different levels exist, such as
     producers (usually plants), primary consumers (herbivores i.e. who eat plants), secondary consumers
     (who eat herbivores), and so on. The food web used to be called the food chain, but the amount of
     cross-links makes the whole thing more properly resemble a web than a simple linear chain.
    Most of the links in the food web are weak, meaning that the consumer doesn't depend excessively on
     what it consumes. As long as the links are weak, no species will be greatly affected by a predator or
     prey whose population changes. Strong links means that species are greatly affected by changes in the
     populations of species they're linked to; if there are many strong links in the system, drastic changes in
     one species spread through the system along the strong links, destabilizing it.

    2008 Fall Lecture 5                                 SCIE 103 Life Sciences                                                66