Keystone and Keynote Species

Wayne C. Weber contopus at
Sat Jan 12 05:42:24 PST 2002


A keystone species, as you stated, is a widely-used ecological term
for a species that plays a critical role in an ecosystem-- especially
one that greatly affects the habitat, and thus the likelihood of
survival of other species in that ecosystem. Other examples, besides
the one you quoted, are bison in the prairie grasslands, sea stars in
intertidal communities, or beavers in northern wetlands. I'm not sure
who first used this term, but it seems to have crept into ecological
literature within the last 20 years or so.

A keystone species is not the same thing as an indicator species,
which is a much older term for a species whose presence or abundance
can be used as a barometer of the general health of an ecosystem, or
of the presence of certain pollutants (e.g. certain lichen species as
an indicator of air pollution).

A "keynote species", as far as I can determine, is not an ecological
term (as Liz Donelan indicated), and is a misapplication of "keystone
species", despite its use in the webpage that you quoted. I did an
"advanced search" using AltaVista, and found about 3600 occurrences of
"keystone species", but only 9 of "keynote species". Basically, it
looks like somebody goofed.

Wayne C. Weber
Kamloops, BC
contopus at

----- Original Message -----
From: <JLRosso at>
To: <tweeters at>
Sent: Friday, January 11, 2002 9:21 PM
Subject: Keystone and Keynote

> I am trying to determine if there are two separate terms: keystone


> keynote. A keystone species is one that if it were removed from a

habitat the

> habitat would experience a strong change. The Alligator in the

Everglades is

> mentioned as an example of a keystone.

> I remember keynote species as being a species that represents the

health of a

> particular habitat. I think of Common Yellowthroats as being a


> species of a marsh habitat. Surfgrass is defined as a keynote

species because

> it plays a strong role and is sensitive to change.



> keynote and keystone the same?

> Can anybody mention a good reference that I can go to?


> Thanks


> Jim Rosso

> Sammamish

> jlrosso at

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