Please enable JavaScript.
Coggle requires JavaScript to display documents.
C4 - Conservation and Biodiversity - Coggle Diagram
C4 - Conservation and Biodiversity
Extinction
Extinction is the complete disappearance of a species from Earth. Species go extinct every year, but historically the average rate of extinction has been very slow with a few exceptions.
Red List Index: shows trends in overall extinction risk for species, and is used by governments to track their progress towards targets for reducing biodiversity loss.
An indicator species is an organism whose presence, absence or abundance reflects a specific environmental condition.
Biological Biodiversity
has two components
Richness = number of different species present
Evenness = how close in numbers each species is.
Calculating a Biotic Index
A biotic index is a measure of the health of an ecosystem. Intolerant species score highly, so a clean ecosystem will have a higher biotic index than a polluted ecosystem.
Large Size Vs. Small Size
Large sites will avoid extinction with unexpected
Large sites: more resources and breeding sites
Skills
BI = Σ(ni x ai) / N
Features that affect biodiversity
Edge effect = boundaries between habitats or ecosystems.
At the edge of the forest, there is more sunlight, more wind and less moisture than at the center --> decreased population on the edge.
Forest fragmentation: slipt in half by roads or farms
Exception: Cow birds thrives at the edge where it lays its eggs --> increase in Cow bird population
Nature reserves: the edge effect
This describes the boundaries between habitats or ecosystem. One example is the boundary between forestry and cleared or agricultural land.
The boundary is not a 'wall' - there is disturbance from the outside which extends into the forest. If the forest is more fragmented and more edges, more of the forest will be disturbed.
The edge effect is a benefit to some species: Cowbirds forage in open areas, but lay eggs just inside woodlands. Fragmented reserves have more edges, therefore the cowbird thrives.
Disturbance generally will decrease biodiversity, but there are exceptions.
Corridors = used to connect isolated populations.
WWF established corridors between 40 isolated panda populations.
Active Management of Endangered Species
Human intervention. Techniques: restoration land to natural state. Recovery of threatened species. Removal of introduced species. Legal protection against development or pollution. Captive breeding. Reintroduction programs.
Conservation methods:
Advantages In Situ
Species remain adapted to their habitat. Animals maintain natural behavior patterns. Species interact with each other, help to conserve the ecosystem
GPS tagging of whales
Conserve in own habitat
Advantages of Ex Situ
Some species become too rare (last chance survival). Destruction of natural habitat can be necessary to remove threatened species.
Captive breeding of pandas
Seed banks store for replanting