rare species

[Kristina Lemson]

One issue in dealing "rare" species is how to differentiate between "rare"
and "not commonly collected", and the dangers of producing "rare" lists
purely from herbarium collections.
The Western Australian government authority charged with conservation ( and
which includes the PERTH herbarium) uses a system of "Priority Listing"
with respect to Flora, in which the use of "RARE" has three (!)
connotations. The list differentiates between:

Declared Rare Flora, (DRF) which are taxa "in serious risk of disappearing
in the wild within 1-2 decades if present land use and other causal factors
continue to operate"; these taxa are subject to legislative protection, and
to be listed have to have been well-defined, thoroughly surveyed and to be
deemed from the survey to be  "rare", endangered or threatened and in need
of protection. They are "gazetted" ie published in an official list each
year, and there are fines applicable for taking or interfering with these
taxa.

Taxa which are "rare" but not gazetted as DRF are categorised via a series
of Priority listings, which attempts to differentiate the "poorly known"
taxa from "rare" taxa.
Priority 1 (P1) taxa-Poorly known taxa known from only one or a few  (<5)
populations which are under threat, and in urgent need of survey
P2- Poorly known taxa known from a few populations some of which are not
threatened but in urgent need of further survey
P3- Poorly known taxa known from several populations, at least some of
which are not believed to be under immediate threat; these taxa are under
consideration for declaration are "rare flora", but but are in need of
further survey
P4- Rare taxa- adequately surveyed, and while rare (in Australia) are not
currently threatened by identifiable factors & require resurvey each 5 yrs.

The term RARE is defined as "less than a few thousand adult plants of the
taxon existing in the wild", and doesn't go into the issues of whether the
species is of low density across a wide area or in a single population.

Whilst this listing method is not perfect, it at least gives botanists in
Western Australia some "hooks" on which to hange discussions of rarity, and
allows local taxonomists and managers to talk in the same language. It is
also useful within the context of a state which is extremely large in
land-mass, with big areas which have been poorly collected from and in
which a large portion of the flora is thought to be undescribed or
undiscovered, but which requires management just the same. A major project
over recent times has been the initial survey work associated with
producing a comprehensive listing, and interaction between the Rare Flora
Survey staff and taxonomists has been of great benefit. In my case,
several newly discovered taxa have either been discovered in the Rare Flora
survey process, or I have been able to alert the Govt staff to their
existence; some have gone directly onto the list.I would be interested to
hear of other attempts to deal with the "poorly known" issue.