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Biodiversity
Biodiversity
is the ordered complex in which all species are harmoniously co-adapted.
This is a good definition because we think of biodiversity as a resource
that helps us to assess the impacts to that resource and gives us another
measure of environmental impact. Just because an ecosystem exists does
not mean it is healthy as evaluated by biodiversity. The following are
the various environmental resources that are evaluated to determine if
problems exist:
- air quality
= chemical concentrations, odor, visual
- water
quality = chemical concentrations, temperature, pH, flows, microbiology,
taste, odor
- soil
quality = chemical concentrations, odor
- biodiversity
= indicator species
Just as
we tried to model resource consumption, we need to measure biodiversity.
The key to doing this is to recognize that not all species have the same
role within the environment. Some species once removed have an obvious
effect on the environment and are known as key or indicator species. An
analogy is the removal of your tonsils versus your heart. You can think
of your heart as a key organ, or an indicator organ. Can you think of
any key species? One example is rabbits in a grassland. If the rabbits
are eliminated, there will be significant changes to the grassland habitat.
Biodiversity
is therefore measured, or assessed in terms of key indicator species.
There are different types of losses of species as follows:
- Depletion
of a once common species - the species is gone, but the habitat still
exists and the species could be replaced though there is still some
loss of the gene pool. Example: buffalo/cows
- Local
or global species extinction - the species is gone forever and all current
and potential adaptations are lost. This happens all the time. The concern
is that historically losses occurred at a slow enough rate for ecosystems
to adapt, however, anthropogenic induced losses are happening at a much
faster rate. Example: the deforestation rate of extinction is now 10,000
times that before human civilization.
- Ecosystem
disruption - this is the most serious of the three because not just
1 species is lost, but an entire ecosystem. Example: ecosystem lost
as a result of 3 Gorges Dam in China.
The important
point is that we may use the indicator/key species to identify losses
that may be occurring and prevent them from occurring.
IV.1
Biodiversity as a Result of Evolution
IV.2
Importance of Biodiversity
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