An " indicator species " has a narrow set of ecological requirements, therefore they become useful targets for observing the health of an ecosystem.
42.
But their work may be even more directly useful to humans because alligators, at the top of the food chain, are an indicator species.
43.
It is an indicator species for newly accreted mudbanks and is an important species for wildlife, especially spotted deer ( " Axis axis " ).
44.
The presence of this indicator species shows good water quality; it has vanished from some locations due to pollution or increased silt load in streams.
45.
Because of its large numbers and readily identified behaviour, the oystercatcher is an important indicator species for the health of the ecosystems where it congregates.
46.
Like canaries in mines, frogs in nature are considered an indicator species _ their decline signals a loss of life and biodiversity throughout an area.
47.
Species which are particularly characteristic of ancient woodland sites are called ancient woodland indicator species, such as pollen analysis are also indicators of forest continuity.
48.
Inland Silversides are currently an EPA approved indicator species for acute marine aquatic toxicity testing and short-term chronic toxicity estimating of marine and estuarine organisms.
49.
She regards it as an excellent indicator species, an animal far enough up the food chain that if it is doing well, so must its habitat.
50.
"A lot of people care about birds, " she said, " and they're also a good indicator species of the state of the natural world ."
