Approaches to conservation

In situ
1. Protecting species 'on site' in their natural environments
  1. More than 20,000 protected sites globally
    1. Limitations: - Areas too small to maintain pops of large animals, e.g. 80% African elephants outside of protected zones
      1. - Uneven distribution globally: tend to be in poorer countries, therefore not representative of all habitats.
        - Isolated from eachother and changes in distributions - natural or as result of climate change - not taken into account.
        - Lack of practical application: Park boundaries, anti-poaching patrols et.
        Inadequate c.0.5% oceans protected.
2. Research
  1. Identification of cause of decline/threats
    1. Enables implementation of most appropriate action
      1. e.g. Australian Bandicoots - breeding high, but predation by cats issue.
    2. Survivorship curve: type 1, 2, or 3?
      Anmerkungen:
      - [Image: http://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/16372152/f1_rauschert.jpg] Figure 1 : Idealized survivorship curves In Type I survivorship, mortality rates are low until late in life. In Type II survivorship, a constant proportion of individuals die throughout the life cycle. In Type III survivorship, juvenile mortality is very high; individuals surviving past that initial phase have higher survivorship
  2. Population variability analysis
    1. Assigning priority
      1. "Red Data Books" label species: extinct, extinct in wild, critically endangered, endangered, near threatened, least concern, data deficient, not evalu
        Allows for identification of where conservation is required.
    2. Species diversity indices analyse species richness and relative abundance, helps identify where conservation is required.
      1. rarity doesn't necessary equal under threat- rarity natural sometimes
3. Interventions
  1. Habitat protaction and management
    1. Protective legislation- African elephant: Placed on CITES Appendix 1 making ivory trade illegal
      1. Populationhad declined by 85& '73-'87, but mostly revived due to decline in poaching.
  2. Restoration ecology
    1. Reducing pollutants, planting roughage for nests/steams for spawning.
      1. Negative feedbacks: benefitting one species to detriment of other.
  3. Eradication/prevention of invasive species.
  4. Re-introductions: deliberate movement of individuals back into natural range - can be linked to ex-situ breeding mehtods.
    1. Golden lion Tamarin Monkey: Bred in captivity when numbers dropped to c.100. Re-released in wild (Brazil) and now 800. Also education for local people
  5. Red howler monkey, French Guiana
    1. Translocation: original area flooded so some individuals removed and released at another similar site
      1. Successful, but many examples not succesful due to competition, predation, pathogens etc.
    2. Population reinforcement: Local hunting had reduced the local population density of howler monkeys at release site.
Ex situ
1. Should always play a secondaty role to in situ.
  1. Compliments in situ conservation with abilty to re-introduce animals bred in captivity.
    1. Captive breeding - ethical issues. But living collections may provide last refuge for endangered species which only exist in captivity.
      1. Advantages: reintroductions, reduced infant mortality, less need for translocation, maximising genetic variability through selective breeding.
        Disadvantages: May threaten wild pop., ecological requirements not met, limits of space, loss of genetic diversity, hybridisation, human imprinting
      2. Failure: Sumatran Rhino: 40 taken into zoo for breeding, 20 died and none were born over 17yrs.
2. "Living collections" e.g. zoo's, aquariums, botanic gardens.
3. "Banking biodiversity" e.g. Kew seed banks (1.5 billion seeds), 'Frozen Ark' cryogenic freezing of animal cells.
4. Red Kite: re-introduced to England from Europe after almost becoming extinct due to hunting and habitat depletion in 19th century.

Nächster

Approaches to conservation

Beschreibung

Zusammenfassung der Ressource

ähnlicher Inhalt

	Erstellt von sian_clarke_xx vor mehr als 11 Jahre