An assessment of terminology for intra-specific diversity, with a focus
on “ecotypes” and “life histories”
Abstract
Understanding and preserving intra-specific diversity (ISD) is important
for species conservation. However, ISD units do not have taxonomic
standards and are not universally recognized. The terminology used to
describe ISD is varied and often used ambiguously. We compared classical
and authoritative definitions of terms used to describe ISD with terms
used in recent studies of three fish taxa: sticklebacks
(Gasterosteidae), Pacific salmon and trout (Oncorhynchus spp., “PST”),
and lampreys (Petromyzontiformes). Our review revealed the
terminological ambiguity of “races” and “subspecies”, found similar
definitions of “subspecies” and “ecotype”, and of “ecotype” and
“reaction norms”. “Species pairs” describes two phenotypes; however,
in some situations more than one phenotype may occur. “Ecotype” was
originally used to describe patterns in genes and ecology, and recent
studies employing this term tend to report a genetic basis in ISD.
Ecotype is used most frequently in genetic- and evolution-based
journals. By contrast, “life history” includes biological parameters
that affect population growth and decline, and this term tends to be
used in organismal- and ecology-based journals. When the genetic or
demographic components of ISD are not well understood, a conservative
approach would be to refer to expressions of this diversity as
“phenotypes”. The nature of human interests in particular taxa could
influence how these organisms are studied, and hence the ways in which
their ISD is understood, described, and conserved.