Subspecies definitions and legislation: from eastern wallaroo (Osphranter robustus robustus) to euro (Osphranter robustus erubescens)
As a consequence of genetic studies of population structuring, the usefulness of subspecies has been questioned, with opinions divided. The situation is further confused by the use of varying species and subspecies concepts. Most alternatives require each taxon to be following an independent evolutionary trajectory. These include traditional approaches and the more recent phylogenetic species concept. The latter has led to large increases in the apparent number of taxa in some groups, though strong objections have been raised to this approach. An alternative, the ecological species concept, has been opposed by phylogeneticists. These two approaches are compared using morphological and genetic data from common wallaroo (Osphranter robustus) populations. The different taxonomies that might result (many species, one species with two subspecies, one species with no subspecies) can have significant consequences for legislative and management decisions. The ecological approach is considered preferable for subspecies and the present taxonomy is maintained. A potential location of the boundary between the wallaroo subspecies is proposed. How the use of the different subspecies definitions would affect legislative decisions is explored.