C4 ~ Conservation of Biodiversity

Indicator species

• Organisms that are only present when specific environmental conditions are met

• The presence or absence of these organisms can be used as an indicator for environmental conditions

Biotic index

• Compares the relative frequencies of indicator species

  • Can therefore be used to assess and quantify the levels of pollution in an area

• Indicator species found in water are usually sensitive to O2 levels (the more polluted an area, the lower the O2 levels)

In situ conservation methods

• Involves managing the conservation of a species in its natural habitat

• This allows organisms to continue to interact with other species in their natural habitat/niche

• Examples of in situ conservation methods are national parks or nature reserves

  • These are usually areas that are protected from human influences that may cause harm to these species

• national parks/ nature reserves also nee active management to ensure the survival and proliferation of a species

  • Includes controlling invasive species and predators, controlling poaching, access or grazing, feeding the animals, reintroduction of species that are mutually beneficial

Advantages of in situ conservation methods

• Many species have been rescued from the brink of extinction by captive breeding programmes e.g. bald eagle, golden lion tamarin, red wolves

• One of the most famous species in captive breeding programmes is the giant panda

Ex Situ conservation methods

• Ex Situ conservation are measure taken to preserve species by removing them rom their natural habitats

• E.g. include Botanic Gardens (plants) and captive breeding programmes in zoos

• Ex Situ conservation is used to back up in situ conservation methods

  • They are usually implemented when a species cannot safely stay in their natural habitat and/or are so endangered that they are at high risk of extinction

Giant panda and conservation methods

• The giant panda is one of the most endangered species in the world

• They have low rates of conception and show little effort to procreate

• As such, their numbers have been rapidly declining for decades

Richness

The number of different species present

Evenness

How close in numbers each species is

Simpsons reciprocal index of diversity

• Measures biodiversity in an area by taking into account the species’ richness and evenness

• High index may indicate an ecosystem that is rich and even

The Edge effect

• The change in ecosystems, communities and habitats at the edge of a nature reserve

• The ‘edge’ of a nature reserve will have increased abiotic and biotic interactions with the surrounding areas that do not exist in the core

• E.g. if the outside of a nature reserve is a road, this will impact abiotic factors such as light intensity and temperature, and human interaction such as poaching

• This causes greater levels of disturbance and can negatively impact biodiversity

• To minimise the edge effect

  • Have transitional zones between the edge of a nature reserve and the surrounding area where human interactions are limited and vegetation can provide a ‘buffer’

  • Consider the shape of the nature reserve to minimise the edge effect

Fragmentation of habitats

• Roads/ walkways can fragment (divide) habitats into smaller areas

• This negatively impacts biodiversity by:

  • Isolation populations and impeding migration routes

  • Increasing the edge effect by adding more ‘edges’

  • Limiting provisions for larger species (as the habitats are much smaller)

Wildlife corridors

• Connected nature reserves are more effective than isolated ones

  • They can minimise the effect of fragmentation of habitats by allowing migration

• They allow migration and interbreeding of plant and animal species to help reserve biodiversity

Island size

• Larger nature reserves are usually better than small ones as:

  • They can support more ecosystem, habitats and species

  • Reduces the edge effect (as the core is larger)

  • Provides for larger species, thereby increasing biodiversity

  • Allows for migration within the reserve

  • Allows for populations to increase in size so they are less likely to be affected by sudden events