6.3.2 Populations and sustainability

• What is conservation?

  To maintain/ manage nature to protect species and habitats
• What is preservation?


  Leaves the environment/ lands not to be used by humans by leaving it untouched
• Why is conservation important?

  • economic; ecotourism, potential for future medicines
  • social; aesthetic, stop the impact of deforestation
  • ethical; preserve biodiversity/ stop extinction, supports indigenous population
• What are the aims of sustainability?

  • preserve environment
  • ensure resources are available to future generations
  • allow humans in all societies to live comfortably
  • enable less economically developed countries to develop through exploiting their natural resources
  • create a more even balance in the consumption of these resources in more economically developed countries and less ones
• What is coppicing?

  trunk cut close to ground level

  several new shoots grow from cut surface

  process repeated after a certain time

  protect young shoots from grazers

  broadleaved species

  rotational coppicing

  can be repeated indefinitely
• advantages of coppicing

  • new stems grow more rapidly than saplings
  • lifespan of tree extended
  • provides variety of light levels
  • fewer large trees so more light for plants
  • provides a variety of habitats so maintains biodiversity
  • roots prevent soil erosion
  • prevents succession
  • large machinery not needed so less disturbance
• what is selective felling?

  cutting down of selected, mature trees in a forest to allow other trees to grow to maturity and leaving enough habitats for animals
• what is rotational felling?

  planting a site and then felling the trees when they have reached maturity, dependent on species (8-10 years)
• what is strip felling?

  the cutting of selected, mature trees from a forest in a strip, allowing other trees to grow to maturity and also leaving enough habitats for animals
• what should you do after felling to be sustainable?

  • limit size of area felled
  • replanting of trees felled
  • minimum distance between replanted trees
  • allow time for new trees to fully grow before next felling
  • limit soil erosion after felling
• how to sustainably fish?

  • introduce quotas, limiting the number of fish caught for certain species
  • certain hole size in nets so smaller fish can escape, reach maturity and breeding age
  • limit fishing to certain times of the year, allowing the population to reach a sustainable level
• human activities that effect habitats

  • destruction of ecosystems and habitats for buildings/ roads
  • deforestation of land used for farming or overgrazing by introduced species
  • increase in boats
  • more pollution from sewage in the seas and oil spills
  • overfishing/ collecting eggs/ hunting
  • competition from introduced species
  • introduction of new pathogens/ diseases
• how do you control the effects of human impact on ecosystems?

  • introduction of park rangers
  • limiting human access to particular islands
  • stricter control on migration and introduction of animals
• antarctica human activity

  • whale and fish impacted by overfishing and whaling, now bans on this and restrictions
  • waste must be taken when leaving
  • boats can’t leave waste in sea
• snowdonia national park and lake district human activity

  • visitors encouraged to use paths to protect native species
  • litter told to be placed in bins/ taken home
  • speed limit on the boats
• what is interspecific competition?

  competition between two different species
• what is intraspecific competition?

  competition between individuals of the same specie, e.g. mate availability
• what is carrying capacity?

  maximum population size a specific environment can support, the populations are not subject to further succession
• Describe a growth curve?

  1. reproduction rate higher than death rate
  2. as time doubles, population more than doubles
  3. reproduction rate is much higher than the death rate
  4. population growth slows
  5. reproduction rate similar to death rate
• Evidence that Antarctic temperatures are increasing

  • water temperature
  • populations of other water animals
  • reduction in extent of ice
  • change in ocean current
  • new disease/ parasite
  • new animal species present on land
  • change in population of aquatic animals
• Suggest explanations for a decrease in population

  • deliberate killing to maintain prey numbers
  • pollution
  • pesticides
  • disease
  • loss of (another) food source
  • competition from new predators
• Explain why Madidi is an example of conservation

  • there are local people present
  • sustainable use for logging, farming, nut production
  • active measures working to maintain biodiversity/ habitat
• Conservation of peat bogs

  • no/less planting as trees remove water from bog
  • no ditch as it drains water from bog
  • no/ controlled grazing as overgrazing disrupts food chain
  • no/ less burning as rare species live in peat bog

  can't preserve as habitat needs to be managed (e.g. raise water levels) as they've been damaged and need to be restored
• Difficulties of sustainable fishing

  • area too large
  • expense of monitoring
  • monitoring can be hampered by weather/ seasons
  • false reporting of catches/ mesh size/ days/ trawler size
  • death of fish caught but not kept because of restrictions