CONSERVATION OF ARABIAN GAZELLES - Nwrc.gov.sa

misdirected with respect to the goal of protecting biological diversity (A vise, 1989). Financial and
socio-political implications mu st also be taken into consideration in the current conservation struggle.
Should the subspecies level be considered in conservation projects The answer is relatively
simple for in situ conservation because projects concern areas where native populations exist. The
question becomes more sensitive with ex situ conservation programmes involving the translocation of
animals. Should ex situ conservation focu s on populations, subspecies, Or species What is the best
policy to adopt in restocking or reintroduction programmes when the only animals available are of
different geographic origin from the native current or past taxon
The subspecies concept: definition and controversy
In order to understand the subspecies concept, let us first recall the definition of the species. The
species concept was originally based on morphological criteria identified using museu m specimens.
More recently, the Biological Species Concept has emphasized reproductive isolation as the basic
criterion (Mayr, 1963).
Since then, various criteria, based on phylogeny, ecology, and genetic
cohesion, among others, have been used to delineate species (see Rojas, 1992 for a review). As yet,
however, no common agreement has been reached on what true species are.
Modem molecular
techniques have recently allowed access to genotypes, which contain the heritable information of an
animal (Hillis, 1987). These techniques provide mOre reliable tools for studying genetic similarity or
phylogenetic relationships between taxa, increasing the understanding of certain taxa (Avise, 1989).
The concept of subspecies is even more vague and controversial (Mayr, 1963). Avise and
Ball (1990) proposed that subspecies should be defined as "groups of actually or potentially
interbreeding populations phylogenetically distinguishable from, but reproductively compatible Wilh,
other such groups. Importantly, the evidence for phylogenetic distinction must normally come from
the concordant distributions of multiple, independent, genetically based traits".
Consideration of
geographical, morphological, behavioural and genetic factors may suggest that isolation and
independent evolution of a geographical race has occurred, implying the likelihood that populations
of this race (or subspecies) may pos sess genes rare or absent in other conspecific taxa (Ryder et ai.,
1988). Members of a subspecies should share a unique geographic range or habitat, a group of
phylogenetically concordant phenotypic characters, and a unique natural history relative to other
subdivisions of the species (O'Brien and Mayr, 1991 ). This concept emphasizes the importance of
local adaptation.
To enhance the success of reintroduction projects, it seems logical to release
animals that have the best chances of fitting within the ecosystem. Although the subspecies concept
represents a biological reality, its application requires a good understanding of the distribution of the
different local races within a species and their comparative degree of differentiation.
information is often lacking, it is difficult to find clear features to define the su bspecific level.
As such
The traditional classification of subspecies, based mainly on small numbers of morphological
characters, is being subjected to more and more justified criticisms and is increaSi ngly controversial.
Should we consider this taxonomic level in wildlife management The following sections preselll
arguments for and against the consideration of subspecies in conservation.
Arguments against subspecies consideration
The arguments against the recognition of subspecies in conservation biology can be divided into
categories: taxonomic, technical, biological and practical.
52