20
Mark Burgman et al.
setting of conservation priorities depends on sound taxonomy, for without it,
conservation has nothing to work with. Clearly defined taxa are the result of
taxonomic research, and the names applied to the biological entities are the means
whereby information about them is exchanged. Thus, in circumstances in which
the conservation of species is a priority, the first priority for taxonomy should be
straightforward species circumscription and description (alpha taxonomy).
Of the taxa that were described before 1970, 43 were found subsequently to be
confounded with at least one other taxon. In these cases, subsequent revision has
separated these closely related or similar species and circumscribed the new taxa
in their own right. Again somewhat obviously, such changes lead to substantial
changes in the evaluation of the conservation status of the taxa. For example, A.
bifaria was segregated from A. glaucoptera in 1995. Before then, specimens of
the two taxa were not differentiated. A. bifaria was not afforded any protection
because A. glaucoptera is common and widespread. Similarly, A. browniana was
composed of taxa currently recognized as A. browniana, A. grisea, A. lateriticola,
A. luteola, A. newbeyi, and A. subracemosa, all of which are listed on the priority
flora list. Few of the species currently recognized in the declared rare flora list or
the priority flora list would have been guaranteed protection in Western Australia
if the taxonomy of the Acacias had not progressed beyond that known in 1970.
Efficacy of the Methods
The methods applied here are intended to enhance the ability of managers to set
conservation priorities, not to replace existing procedures. The objective of these
methods is to highlight unusual patterns in collection frequency and find reasons
for them. The relative magnitudes of the probabilities for the taxa are important,
not the absolute values. Biological explanations such as range contraction or
population decline should be considered only after more mundane explanations
such as changes in taxonomic interest (whether or not a taxon is the subject of
current taxonomic research) have been discounted. The results of the equations
provide a mechanism to stimulate conservation and land management authorities
to consider why there are unusual collection patterns for different taxa. If there are
no simple explanations in terms of other factors, then managers may have to
consider specific surveys to establish the current conservation status of the taxa.
For example, of the 192 Western Australian Acacia taxa recognized as declared
rare and priority flora list taxa, 41 were detected by one or other of the equations
applied here as having unusual collection patterns. Of these, 23 were scrutinized
carefully, and of these, nine species were suggested to warrant further survey. This
does not mean that the nine taxa are on the brink of extinction. Rather, the
information resulting from our analyses has been used together with other relevant
information to improve the assessment of their conservation status.
The discrepancies between taxa identified by our results and those identified by
other means do not indicate a failure of the respective methods. Range size,
population size, number of populations, and the rates of change of these parameters are central in setting conservation priorities (IUCN 1994). Population size, the
Mark Burgman et al.
setting of conservation priorities depends on sound taxonomy, for without it,
conservation has nothing to work with. Clearly defined taxa are the result of
taxonomic research, and the names applied to the biological entities are the means
whereby information about them is exchanged. Thus, in circumstances in which
the conservation of species is a priority, the first priority for taxonomy should be
straightforward species circumscription and description (alpha taxonomy).
Of the taxa that were described before 1970, 43 were found subsequently to be
confounded with at least one other taxon. In these cases, subsequent revision has
separated these closely related or similar species and circumscribed the new taxa
in their own right. Again somewhat obviously, such changes lead to substantial
changes in the evaluation of the conservation status of the taxa. For example, A.
bifaria was segregated from A. glaucoptera in 1995. Before then, specimens of
the two taxa were not differentiated. A. bifaria was not afforded any protection
because A. glaucoptera is common and widespread. Similarly, A. browniana was
composed of taxa currently recognized as A. browniana, A. grisea, A. lateriticola,
A. luteola, A. newbeyi, and A. subracemosa, all of which are listed on the priority
flora list. Few of the species currently recognized in the declared rare flora list or
the priority flora list would have been guaranteed protection in Western Australia
if the taxonomy of the Acacias had not progressed beyond that known in 1970.
Efficacy of the Methods
The methods applied here are intended to enhance the ability of managers to set
conservation priorities, not to replace existing procedures. The objective of these
methods is to highlight unusual patterns in collection frequency and find reasons
for them. The relative magnitudes of the probabilities for the taxa are important,
not the absolute values. Biological explanations such as range contraction or
population decline should be considered only after more mundane explanations
such as changes in taxonomic interest (whether or not a taxon is the subject of
current taxonomic research) have been discounted. The results of the equations
provide a mechanism to stimulate conservation and land management authorities
to consider why there are unusual collection patterns for different taxa. If there are
no simple explanations in terms of other factors, then managers may have to
consider specific surveys to establish the current conservation status of the taxa.
For example, of the 192 Western Australian Acacia taxa recognized as declared
rare and priority flora list taxa, 41 were detected by one or other of the equations
applied here as having unusual collection patterns. Of these, 23 were scrutinized
carefully, and of these, nine species were suggested to warrant further survey. This
does not mean that the nine taxa are on the brink of extinction. Rather, the
information resulting from our analyses has been used together with other relevant
information to improve the assessment of their conservation status.
The discrepancies between taxa identified by our results and those identified by
other means do not indicate a failure of the respective methods. Range size,
population size, number of populations, and the rates of change of these parameters are central in setting conservation priorities (IUCN 1994). Population size, the