What is an indicator species???

Question

what is an indicator species and how are they used in defining habitats?? in relation to rocky shore ecosystem field study. just a general, simple explanation please??

Answer 1

Indicator species are those whose presence or absence lets you know something specific about an environment.  For example, stoneflies in streams are an indicator that there is sufficient dissolved oxygen.

On the rocky shore, indicator species tell you about the wave height.  Zonation patterns are created because of physical tolerances and competition among species.

For example, if you see green algae, encrusting red algae, sea stars and urchins then you know you are in an area that is nearly always submerged.  Browns like Ascophyllum and mussels are in mid-tide regions.  The highest barnacles will tell you where the mid-high tide line is.  And, grazing snails will be way up in the splash zone along with plants like Salicornia.

Here's a good diagram of zonation patterns: http://www.glf.dfo-mpo.gc.ca/os/bysea-en...

Answer 2

an indicator species is a species that is used to acess some factor of an ecosystem, typically the general health. it could be more specific and be an indicator for another species if they survive in the same area and are affected similarly. usually they are something that is easy to find and study and in abundant numbers.

for a specific example to the seashore mollusks are oten used. as a filter feeder they can be used to see what is in the environment(pollutants etc). assuming that the effect of what is found is known in regards to the target it is an easy way to judge it.

-lots of mercury in mollusk fish may be sick