Indicator Species
The presence, absence or
relative abundance of indicator species reflects environmental conditions;
therefore they can be used as a management tool for early warning signs of disruptions to a habitat or ecosystem. Whilst
mapping can give an indication of changes in a habitat or ecosystem, observing
indicator species can show the impact of these changes over time.
Examples of Indicator
Species
In certain wetlands, wood
frogs depend on vernal pools, which are free of predators yet are becoming
increasingly threatened by changes such as pollution, deforestation and even
climate change. Studying these frogs allows scientist to know the health of the
wetland ecosystems. If the frogs’ population dwindles, then it is a sign that
the health of this wetland ecosystem is suffering, and the scientists can then
study the pools further to prevent damage to it.
Other good indicator
species include alpine flowers, which offer clues about changing conditions on
high peaks; they are at great risk from climate change because they are rare
flowers with restricted ranges of where they can grow. By observing when they
flower and how long they flower for, scientist can use the species’ life cycles
to see if they are beginning to ‘exhibit biological shifts’ (Wroth, 2011). If
these shifts are occurring, this could mean that the environment on these high
peaks is changing and this change is affecting its ecosystems.
Another example of an
indicator species is lichens. Lichens grow in exposed places such as rocks or
bark and are very sensitive to sulphur dioxide. They receive their nutrients
from the rain water there by absorbing water; therefore air pollutants
dissolved in rain water can be very damaging for lichens. If sulphur dioxide is
in the air, then lichens could be less abundant or absent from areas where they
are normally found. This can suggest to scientists that there is an air
pollution problem in that area.
Air pollution is similar to
water pollution; many aquatic invertebrate animals cannot survive in polluted
waters, so their absence provides scientists with information on how polluted
the water is.
Support
To support the study of
indicator species, in 1997 Alfaro and Singh discovered that the abundance of
invertebrates in a forest canopy is higher in forests which have not been
damaged. Therefore, invertebrates are good indicators for showing the health of
a forest.
Conclusion
In summary, indicator
species is a species or group of species which suggest the health of a habitat or ecosystem; by observing this species, other species which share its ecosystem, those
which are also affected by the same threats, or even the ecosystem itself,
could be protected for the future.
Emma Barkley, 16th
April
All Accessed 16th
April:
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