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  • Forest damaged by acid rain in the NE US.
  • Acid rain has long-term effects on nutrient cycling and regeneration. Particulate and sulfur emissions and measures of pH and calcium in the Hubbard Brook watershed are shown for the period before and after passage of the Clean Air Act in 1970.

3. Human Impact 3. Human Impact Presentation Transcript

  • Human’s Biological Impact
  • 4 Serious Environmental Issues
    • 1. Biomagnification
    • 2. Ozone Depletion
    • 3. Acid Rain
    • 4. Greenhouse Effect (Global Warming)
  • At each trophic level, toxic substances (Hg, pesticides, TCDD, etc.) become more concentrated 1. Biomagnification
  • Ultraviolet Radiation and the Ozone Layer
    • With a depleted ozone layer, more UV radiation will reach the surface of Earth
    • This will cause an increase in many problems, including cancer, will affect crops, damage phytoplankton and zooplankton
    2. Ozone Depletion
    • Stratospheric ozone continues to decline
      • Ozone is a natural component of the stratosphere
      • Ozone shields the surface of the Earth from UV radiation
      • Ozone depletion has appeared over Antarctica most demonstrably first in 1984
    2. Ozone Depletion
  • 2006
    • Certain chemicals destroy stratospheric ozone
      • Chlorofluorocarbons ( CFCs) are broken down by UV in the stratosphere and react with ozone, forming molecular oxygen
      • CFCs are not used up in this reaction, and are able to break down many thousands of ozone molecules
  • Ozone Depletion Is Harmful
    • Ozone depletion harms living organisms
      • Exposure to UV is linked to disorders in humans, including cataracts, skin cancer, and weakened immune systems
      • Exposure to increasing UV is linked to declines in phytoplankton productivity
  • Basal Cell Skin Cancer
  • 6% Declines in phytoplankton over the last 10 years map right: Satellites Many of the areas showing an increasing trend appear along the coasts, in red, while most of the dark blue areas indicate a decreasing trend. Units for the top two panels are milligrams of chlorophyll per cubic meter.
    • International cooperation (the Montreal Protocol) will prevent significant depletion of the ozone layer
      • Despite agreements to decrease CFC production, ozone depletion has continually worsened
    • Freon is a trade name for a group of chlorofluorocarbons used primarily as a refrigerant.
    • One major use of CFCs has been as propellants in aerosol inhalers for drugs used to treat asthma.
  • 3. Acid Rain Global Sulfur Cycle
  •  
  • Causes of Acid Rain
    • Burning coal. Oil and natural gas in power stations makes electricity, giving off sulphur dioxide gas.
    • Burning petrol and oil in vehicle engines gives off nitrogen oxides as gases.
    • These gases mix with water vapour and rainwater in the atmosphere producing weak solutions of sulphuric and nitric acids – which fall as acid rain.
  • The Sulfur Cycle 1
    • Sulfur is an essential element and, like nitrogen, has many oxidation states and follows complex chemical pathways.
    • Sulfur reduction reactions include:
      • assimilatory sulfate reduction to organic forms and dissimilatory oxidation back to sulfate by many organisms
      • reduction of sulfate when used as an oxidizer for respiration by heterotrophic bacteria in anaerobic environments
  • The Sulfur Cycle 2
    • Sulfur oxidation reactions include:
      • oxidation of reduced sulfur when used as an electron donor (in place of oxygen in water) by photosynthetic bacteria
      • oxidation of sulfur by chemoautotrophic bacteria that use the energy thus obtained for assimilation of CO 2
  • More problems!!!
    • Acid rain can travel long distances.
    • Often it doesn’t fall where the gas is produced. High chimneys disperse (spread) the gases and winds blow them great distances before they dissolve and fall to Earth as rain.
    • Eg. gases produced in England and Western Europe can result in acid rain in Scotland and Scandinavia.
  • Acid Rain and Forest Decline
  • Acid Rain and Forest Growth
    • Decline in forests, noted in northeastern US and central Europe in the 1960s, appeared correlated with acid rain.
    • The Clean Air Act of 1970 reduced emissions of sulfur oxides and particulates in the US.
    • Forests did not show signs of recovery. Why?
  • Slow Recovery of Forests from Effects of Acid Rain
    • Studies at Hubbard Brook Experimental Forest in New Hampshire showed why forests did not recover after passage of Clean Air Act:
            • acidity of rain declined slowly
            • emissions of particulates declined, reducing an important source of calcium at Hubbard Brook
            • leaching of calcium and other nutrients by acid rain left lasting effects on soil fertility
  • Acid Rain Effects
  • How Acid Rain Affects The Environment
    • Acid rain is an extremely destructive form of pollution, and the environment suffers from its effects. Forests, trees, lakes, animals, and plants suffer from acid rain. Trees
    • The needles and leaves of the trees turn brown and fall off.
    • Trees can also suffer from stunted growth; and have damaged bark and leaves, which makes them vulnerable to weather, disease, and insects.
    • All of this happens partly because of direct contact between trees and acid rain, but it also happens when trees absorb soil that has come into contact with acid rain.
    • The soil poisons the tree with toxic substances that the rain has deposited into it.
    • Lakes are also damaged by acid rain. Fish die off, and that removes the main source of food for birds. Acid rain can even kill fish before they are born when the eggs are laid and come into contact with the acid.
    • Fish usually die only when the acid level of a lake is high; when the acid level is lower, they can become sick, suffer stunted growth, or lose their ability to reproduce.
    • Also, birds can die from eating "toxic" fish and insects.
  • Buildings
    • Acid rain dissolves the stonework and mortar of buildings (especially those made out of sandstone or limestone).
    • It reacts with the minerals in the stone to form a powdery substance that can be washed away by rain.
  •  
  • Transport Currently, both the railway industry and the aeroplane industry are having to spend a lot of money to repair the corrosive damage done by acid rain. Also, bridges have collapsed in the past due to acid rain corrosion.
  • Humans
    • Humans can become seriously ill, and can even die from the effects of acid rain. One of the major problems that acid rain can cause in a human being is respiratory problems.
    • Many can find it difficult to breathe, especially people who have asthma. Asthma, along with dry coughs, headaches, and throat irritations can be caused by the sulphur dioxides and nitrogen oxides from acid rain.
    • Acid rain can be absorbed by both plants (through soil and/or direct contact) and animals (from things they eat and/or direct contact). When humans eat these plants or animals, the toxins inside of their meals can affect them. Brain damage, kidney problems, and Alzheimer's disease has been linked to people eating "toxic" animals/plants.
    • Research carried out in North America in 1982, revealed that sulphur pollution killed 51,000 people and about 200,000 people become ill as a result of the pollution.
  • What are the solutions to acid rain?
  • Solutions
    • Sulphur dioxide can be removed from power stations chimneys but this process is expensive.
    • 2. Reduce the amount of electricity we use
      • turn tv’s off at the mains, don’t leave on standby.
      • turn off lights when a room is not in use.
    • 3. Use renewable energy like wind power, solar panels, tidal power, HEP schemes and geothermal energy.
    • 4. Fit catalytic converters to vehicle exhausts which remove the nitrogen oxides.
    • 5. Limit the number of vehicles on the roads and increase public transport.
  • 4. Greenhouse Effect Global Warming
  • Sunlight energy in the atmosphere © Windows to the Universe
  • The layers of the atmosphere The troposphere is the part of the atmosphere in the biosphere The stratosphere contains the ozone layer The stratosphere is also a zone of warm air that keeps a lid on the troposphere. It does not mix with the upper atmosphere © Windows to the Universe
  • The Greenhouse Effect © Oceanworld 2005 Robert R Stewart
  • The Greenhouse Effect
    • The molecules of some gases in the atmosphere absorb heat energy and retain it
    • This can be a good thing
    • Without an atmosphere the Earth would have same temperature as the moon
    • Moon mean surface temperature -46°C
    • Moon temperature range: -233 to +123°C
  • The Greenhouse Gases
    • H 2 O vapor
    • CO 2
    • CH 4
    • NO x
    • CFC
    © Oceanworld 2005 Robert R Stewart
  • Infrared Absorption Spectra © Oceanworld 2005 Robert R Stewrt
  • The Greenhouse Gases
    • Water vapor in the atmosphere is stable
    • The atmosphere is saturated
    • CO 2 levels are currently rising
    • They have varied in the past
    • Methane levels are increasing: as more cattle are farmed, as more paddy fields are planted, as permafrost melts
    • NO x levels increase due to increased circulation of motor vehicles
  • Mauna Loa Observatory © Mauna Loa Observatory Site © Earth System Research Laboratory © Earth System Research Laboratory
  • Carbon dioxide a greenhouse gas © Mauna Loa Observatory Site
  • South Pole Data
  • Samoa data
  • © Australian Antarctic Division © New Scientist : Environment
  • Levels during the last ice age
  • Out of the ice age
  • Since the Industrial Revolution Concentration of Carbon Dioxide from trapped air measurements for the DE08 ice core near the summit of Law Dome, Antarctica. (Data measured by CSIRO Division of Atmospheric Research from ice cores supplied by Australian Antarctic Division)
  • The oceanic conveyor belt
  • The melting Arctic ice The length of the melt season inferred from surface temperature weekly data has been increasing by 9, 12, 12, and 17 days per decade in sea ice covered areas © NASA
  • Is it really getting warmer © NASA 1979 2003
  • The consequences
    • Sea level rise Flooding coastal areas. Reduced agricultural land. Displacement of populations.
    • Climate change Displacement of ecosystems. Change in range of insect vectors of pathogens. Reduced biodiversity.
  • The consequences
    • Increased rates of photosynthesis
    • Increased agricultural production at high latitudes
    • BUT faster growth means: less protein in cereals trees taller and more exposed to storm damage
  • Knock-on effects
    • Increased temperature melts the permafrost
    • Frozen plant remains decompose
    • More methane released
    • Similarly soils will lose organic carbon (humus) more rapidly in a warmer climate
    • Ice caps melt more sea exposed
    • Snow reflects light (high albedo)
    • Water absorbs light, increases warming
    • More CO 2 dissolving in water lowers pH
    • Currently this is buffered and remains stable
    • Eventually pH will drop sea life will die CO 2 produced as organisms decompose
  • What can be done?
    • Reduce carbon emissions
    • Improve mass transport systems (public transport)
    • Design more efficient motors
    • Design alternative power sources
    • Hydrogen powered motors
    • BUT problems of fuel reservoir, delivery, fabrication
    • Renewable energy (wind, tidal, hydro, geothermal, biomass)
    • BUT growing crops for biofuel reduces farmland available for food Hydroelectric dams disrupt river ecosystems
    • Nuclear power
    • BUT problems of nuclear waste treatment/storage
  • What can be done?
    • Increase natural CO 2 sequestering
    • Reduce deforestation
    • Increase reforestation
  • What can be done?
    • Artificial CO 2 sequestering
    • Filter CO 2 sources using hydroxide scrubbers
    • Injection of CO 2 into deep ocean layers Forms CO 2 reservoirs Impact on sea life unknown
    • Injecting CO 2 into disused oil wells
    • Mineral deposition as carbonates
  • The bottom line
    • Two factors will ultimately govern what happens:
    • 1. Human population growth
    • More people means greater demand for non-renewable resources
    • 2. The ecological footprint of each individual human
    • Higher standards of living usually means higher consumption of fossil fuels
    • The planet will look after itself in the end
    • There are plenty of examples where human communities have disappeared because they outstripped the environmental resources
  • The planet will look after itself in the end
    • Easter Island (Rapanui) in the Pacific
    • Settled between AD900 and 1200
    • Community in severe decline AD 1700
    • Cause: excessive deforestation
    The Moai statues, Easter Island © Martin Gray, World Mysteries
  • The planet will look after itself in the end
    • Chaco Canyon, New Mexico
    • Anasazi culture
    • AD 850 – 1250
    • Cause: Deforestation combined with a decline in rainfall
    © New Mexico Tourism Department
  • The planet will look after itself in the end
    • Mesopotamia
    • Sumerian civilization
    • 3100 – 1200 BC
    • Increased salt levels in soil due to irrigation systems & arid environment
    • Reduced food yield
    © Asociación Cultural Nueva Acrópolis en Barcelona
  • The planet will look after itself in the end
    • Greenland
    • Viking colony
    • AD982 – 1350
    • Cause: Deforestation, soil degradation & cooling of the climate
    © Emporia State University
  • 5. Loss of Biodiversity
  • Species Are Disappearing at an Alarming Rate
    • Species are disappearing at an alarming rate
    • Biological extinction is the eventual fate of all species, but humans are greatly increasing the extinction rate
    • According to the United States Endangered Species Act, a species is declared endangered when it is in danger of becoming extinct
    • A threatened species is one in which the population has become greatly diminished and will probably become endangered
    5. Declining Biological Diversity
  • Humans Contribute to Declining Biological Diversity
    • Fragmentation of habitat for housing, agriculture leads to species decline
    • Pollution greatly affects populations
    • Introduction of exotic species harms native species due to competition, predation, or interbreeding
      • The zebra mussel from the Caspian, introduced into the American Great Lakes These
    • mussels not only cause billions of
    • dollars of damage but have
    • displaced the native clams and
    • mussels
    • The ctenophore Mnemiopsis , introduced to the Black Sea and Caspian •Island populations are particularly sensitive to introductions. The introduction of goats to Abingdon island in the Galapagos wiped out the abingdon tortoise
  • 5. Declining Biological Diversity continued
    • Some species have become endangered or extinct by deliberate human action to eradicate them
      • Prairie dogs, wolves, mountain lions and grizzly bears
      • Commercial hunting, sport hunting and subsistence hunting has led to the decline or extinction of many birds and large mammals
    • Commercial harvesting removes live animals and plants from the wild for research, zoos, and the pet trade
  • Extinction
    • The dusky seaside sparrow became extinct in 1987, primarily due to human destruction of its habitat in Florida
  • The Conservation of Biodiversity
    • Biodiversity is highest in the tropical Rainforest
    • Ethical reasons for conserving biodiversity are that all species have a right to live on this planet.
    • Ecological reasons are that species live with great interaction and dependence on each other. If one species dies out, a food chain is disrupted, therefore disrupting all of the other species as well.
    • Economic reasons are that the rainforest is a source of materials important to human life. Medicinal substances can be taken from a variety of plants in the rain forest, and ecotourism offers a new source of funds for the many impoverished nations these forests exist in.
    • Aesthetic reasons are that the tropical rain forest is one of the most beautiful attractions on this planet. There is variety everywhere in the rainforest.
  • Factors that caused the extinction of one animal
    • The Arizona Jaguar became
    • extinct due to an increased
    • demand for its fur. As the
    • human population increased
    • in the areas inhabited by the
    • jaguar, the hunting and
    • shooting increased and the
    • last of this rare animal was
    • shot in 1905.
  • Factors that caused the extinction of one plant
    • In New Mexico. The Fluffy groundsel
    • is a kind of herbal plant with clusters
    • of yellow flowers. It became extinct
    • because of farming, building, road
    • construction and other sorts of
    • human impact in the American
    • Southwest.
  • Simpson diversity index
    • The index of diversity is used as a measure of the range and numbers of species in an area.  It usually takes into account the number of species present and the number of individuals of each species.  It can be calculated by the following formulae:
    • D = N(N-1) ∑n(n-1)
    • D= Diversity index
    • n = number of individuals of a each species found in an area.
    • N = total # of organisms of all species found in an area.
    • The simpson diversity index is a measure of species richness.
    • A high value of D suggests a stable and ancient site.
    • Example :
    • Crested newt 8
    • Stickleback 20
    • Leech 15
    • Great pond snail 20
    • Dragon fly larva 2
    • Stonefly larva 10
    • Water boatman 6
    • Caddisfly larva 30
    • N = 111
    • N(N-1) = 111(111-1) = 12,210
    • ∑ n(n-1) = (8x7) + (20x19) + (20x19) + (15x14) + (20x19) +
    • (2x1) + (10x9) + (6x5) + ( 30x29) = 2018
    • D = 12,210 = 6.05
    • 2018
    • Example: In another pond there were:
    • Crested newt 45
    • Stickleback 4
    • Leech 18
    • Great pond snail 10
    • N=77
    • D = 2.6
    • Comparing both indices, 6.05 is an indicator of greater
    • diversity.  The higher number indicates greater diversity
    • In extreme environments the diversity of organisms is usually low (has a low index number).  This may result in an unstable ecosystem in which populations are usually dominated by abiotic factors .  The abiotic factor(s) are extreme and few species have adaptations allowing them to survive.  Therefore food webs are relatively simple, with few food chains, or connections between them – because few producers survive.  This can produce an unstable ecosystem because a change in the population of one species can cause big changes in populations of other species.
    • In less hostile environments the diversity of organisms is
    • usually high (high index number).  This may result in a
    • stable ecosystem in which populations are usually dominated
    • by biotic factors , and abiotic factors are not extreme.  Many
    • species have adaptations that allow them to survive,
    • including many plants/producers.  Therefore food webs are
    • complex, with many inter-connected food chains.  This
    • results in a stable ecosystem because if the population of
    • one species changes, there are alternative food sources for
    • populations of other species.
  • The use of biotic indicator for monitoring environmental change
    • Are a good indicator of change
    • Highly sensitive to environmental changes
    • Highly sensitive to population increases or decreases.
    • The numbers of organisms in the indicator species populations, can be measured directly so they are easy to keep track of larger changes that maybe occurring.
  • American Dipper
    • Feeds on aquatic insects and their larvae, including dragonfly, nymphs and caddisfly larvae. It may also take tiny fish.
    • The presence of this indicator species shows good water quality; it has vanished from some locations due to pollution or increased silt load in streams
  • Human Effect on the World Fish Population
    • Overexploitation of species affects the loss of
    • genetic diversity and the loss in the relative
    • species abundance of both individual and/or groups of interacting species.  Overexploitation may include over fishing and over harvesting
    • Historically, humans have fished the oceans, which never seemed to pose a problem due to their abundant resources.  Gear (fish trap, gill nets, electro-fishing) and vessel efficiency modifications have caused a significant decrease in fish populations.
  • Population dynamics of fisheries
    • A fishery is an area with an associated fish population which is harvested for its commercial or recreational value. Fisheries can be wild or farmed.
    • Population dynamics describes the ways in which a given population grows and shrinks over time, as controlled by birth, death, and emigration or immigration. It is the basis for understanding changing fishery patterns and issues such as habitat destruction, predation and optimal harvesting rates.
    • The population dynamics of fisheries is used by fisheries scientists to determine sustainable yields
  • Estimating Fish populations
    • Virtual Population Analysis is a modeling technique commonly used in fisheries science for reconstructing fish numbers using information on death of individuals each year. This death is usually partitioned into catch by fishing industry and natural mortality.
    • Capture-Mark-Recapture Method day one, mark and release the fish. The next day, repeat the sequential sampling and also records the total number of fish marked and unmarked so we can use to estimate of fish population density.
  • The overall catch has decreased fish stocks in many areas of the United States, as catches in each area exceed the maximum number of fish that these fishermen are allowed to take.
  • Fish stocks
    • Though fish farming is increasing, fishing represents the last major exploitation of wild populations by mankind
    ACEL Factory ship
  • A case study: The Peruvian Anchovy ( Engraulis ringens ) Universidad de La Serena
  • The Peruvian Anchovy
    • This is a small (12-20cm), short-lived species maturing in 1 year
    • Anchovy live in the surface waters in large shoals off the coast of Peru and northern Chile
    • Here there are cold currents up-welling from the sea bed bringing nutrients for phytoplankton
    • Plankton is at the base of the food chain.
  • The Peruvian Anchovy
    • The harvest of this fish doubled every year from 1955 to 1961
    • Experts estimated the maximum harvestable yield ( MSY ) at 10 to 11 million tonnes per year
    • Through the 1960s the harvest was about this level
    • The biggest fishing harvest in the world
    • Some of the anchovy were used for human food
    • But a lot was ground into fishmeal for animal feed
  • The collapse of the anchovy fishery
    • In 1972 there was an El Ni ñ o event that brought warm tropical water into the area
    • The up-welling stopped,
    • the phytoplankton growth decreased
    • the anchovy numbers fell and concentrated further south
    • The concentrated shoals of anchovy were easy targets for fishing boat eager to recuperate their harvest
    • The political will was not there to impose reduced quotas
    • Larger catches were made
    • No young fish were entering the population (no recruitment)
    • No reproduction was taking place
    • The fish stocks collapsed and did not recover
  • What is causing the damage to fisheries worldwide?
  • What is causing the damage to fisheries worldwide?
    • Several reasons frequently are listed as causes
    • for the decline:
    • Habitat Alterations Anadromous species (shad, herring, striped bass) - dam construction, river flow too high or low, interferes with eggs development
    • Water Quality and Pollution Problems causes declines in spawning areas (low dissolved oxygen for shad)
    • Over-harvest Uncontrolled harvesting – even if quotas are imposed they need to be policed. This a lead to declines in as an example, shad, striped bass, oysters
  • What is causing the damage to fisheries worldwide?
    • Unrealistic and inflexible quotas
    • Insufficient data on fish populations
    • Improved technology in the fishing industry
  • The result
    • Fish populations are reduced below their recovery level
    • Other non-commercial species are being taken and killed at the same time
    • Other species (e.g. sea birds) are being deprived of a food resource
    • Total ban on some species now imposed: Peruvian anchovy Pacific salmon Newfoundland, Grand Banks cod North Sea Herring
  • Maximum Sustainable Yield (MSY)
    • Based upon:
    • the harvest rate
    • 2. the recruitment rate of new (young) fish into the population
        • a population can be harvested at the point in their population growth rate where it is highest (the exponential phase)
        • Harvesting (output) balances recruitment (input)
        • Fixed fishing quotas will produce a constant harvesting rate (i.e. a constant number of individuals fished in a given period of time)
  • Maximum Sustainable Yield (MSY) K
      • Numbers
    Time 1 2 3
  • Problems with MSY
    • Age structure : If all the age groups are harvested recruitment of young fish into the reproductive group will be reduced. The answer is to use a net with a big enough mesh size that lets the young fish escape
    • Limiting factors : If the limiting factors in the environment change so does the population growth rate
        • Limiting factors set the carrying capacity (K) of an environment
        • Increasing limiting factors will cause K to drop
        • Fixed quotas cannot cope with this
        • Data: For MSY to work accurate data in fish populations is needed (population size, age structure, recruitment rates)
        • Usually these are not well known
  • What is required?
    • Nets with bigger mesh size
    • Regulated fishing methods
    • More data on fish populations (e.g. by fish tagging investigations – mark and recapture)
    • Constant monitoring to observe changes in environmental factors (e.g.El Ni ñ o events
    • Policing of fishing industry – respect of quotas
    • International agreements
    • Greater exploitation of fish farming
    • But this is not without its own problems (space, diseases and pollution are all associated with intensive fish culture)
  • CONSERVATION
  • In situ Ex situ
    • In situ :
    • Conservation of species in their natural habitat
    • E.g. natural parks, nature reserves
    • Ex situ :
    • Conserving species in isolation of their natural habitat
    • E.g. zoos, botanical gardens, seed banks
  • In situ conservation
    • Setting up wild life reserves is not just a matter of building a fence around an area and letting it grow “wild”
    Without grazing animals heathlands which contain a number of rare species will revert to woodland
  • Nature reserves and national parks
    • First the area that is suitable for the creation of a reserve has to be identified and delimited
    • This requires surveys to collect data on key species
    • Property may have to be expropriated
    • A legal framework may need to be set up to control human activities in the area and in it’s immediate surroundings
    • Policing the area may also be necessary
  • Les Ecrins National Park, France Park Park Buffer zone
  • Nature reserves and national parks
    • If part of the area has been degraded due to bad land use it may need restoring
    • Alien species that have penetrated the area may need excluding or eliminating
    • Constant management will be needed to maintain the habitat of the species being conserved
    • This may mean arresting natural succession
  • The advantages of in situ conservation
    • The species will have all the resources that it is adapted too
    • The species will continue to evolve in their environment
    • The species have more space
    • Bigger breeding populations can be kept
    • It is cheaper to keep an organism in its natural habitat
    Wordpress.com
  • However there are problems
    • It is difficult to control illegal exploitation (e.g. poaching)
    • The environment may need restoring and alien species are difficult to control
    Sciencemuseum.org
  • Ex situ conservation Captive breeding
    • The Hawaiian goose was practically extinct in the wild
    • 12 birds were taken into captivity
    • A population of 9000 was released back into the wild
    • The experiment failed because the original cause rats had not been eliminated.
    • The rats eat the eggs and the nestlings of the geese
    State Symbols USA
  • Pere David’s deer success or failure?
    • Pere David’s deer was a native species of China
    • In 1865 18 were taken into zoological collections
    • Meanwhile it became extinct in the wild
    • By 1981 there were 994 individuals scattered through zoological collections
    America Zoo
  • Ex situ conservation
    • Captive breeding of endangered species is a last resort
    • These species have already reached the point where their populations would not recover in the wild
    • It works well for species that are easily bred in captivity but more specialised animals are difficult to keep (aye aye)
    • Isolated in captivity they do not evolve with their environment
  • Zoos: The land of the living dead?
    • They have a very small gene pool in which to mix their genes
    • Inbreeding is a serious problem
    • Zoos and parks try to solve this by exchanging specimens or by artificial insemination where it is possible
    • In vitro fertilization and fostering by a closely related species has even been tried (Indian Guar – large species of cattle - cloned)
    • Even if it is possible to restore a population in captivity the natural habitat may have disappeared in the wild
    • Species that rely on this much help are often considered to be “the living dead”
  • Botanical gardens
    • Botanical gardens show the same problems as captive breeding of animals
    • Originally the role of botanical gardens was economic, pharmaceutical and aesthetic
    • There range of species collected was limited
    • The distribution of botanical gardens reflects the distribution of colonial powers
    • Most are found in Europe and North America
    • But plant diversity is greatest in the tropics
  • Seed banks
    • Seeds can be maintained for decades or even centuries if the conditions are controlled
    • <5% humidity and –20°C
    • Not all species are suited to this treatment
    • Seeds need to be regularly germinated to renew stock or the seeds will eventually loose their viability
    • Seed banks are at risk from power failure, natural disasters and war
    • Duplicate stocks can be maintained
    • Seeds kept in seed banks do not evolve with changes in the environment
  • The doomsday vault - Spitzbergen Bergen Nat Acc of Arts BBC
  • International agencies
    • CITES (The Convention in International Trade in Endangered Species)
    • Set up in 1988 to control and encourage the sustainable exploitation of species
    • The CITES conferences determine the status of a species and whether or not its exploitation requires regulation
    • Species are placed into different appendices depending on their status
    CITES
  • CITES Appendices
    • Appendix 1: Total ban on exploitation
    • Appendix 2: Limited exploitation subject to quotas
    • Appendix 3: Species requiring protection in certain states only
    • Species are reassessed every 2 years
  • WWF (World Wide Fund for Nature formerly World Wildlife Fund)
    • Set up in 1961 as a non-governmental organisation
    • Raises funds for conservation
    • Lobbies parliaments for conservation
    • Runs education programmes
    • Provides advice to government conservation agencies
    • Raises awareness on conservation issues
    WWF