The utility of subspecies classification in evolutionary
studies and conservation
As a rank between population and species, the subspecies is useful for
predicting the evolutionary divergence levels among geographical
populations (Barrowclough, 1982). Populations defined as subspecies are
expected to be more highly differentiated than within groups and should
have separate demographic history. The classification of subspecies
should not be the end but a byproduct of investigations of genetic
variation within a species if patterns that warrant designation of
subspecies are found (Barrowclough, 1982).
The other important utility of subspecies is to inform conservation
decisions. Mayr proposed that subspecies are of conservation importance
for their potential to evolve into full species and their acquisition of
unique characteristics (O’Brien & Mayr, 1991). The emphasis on species
diversity in conservation policy had driven taxonomists to revise
subspecies upward to species (Mallet, 2007). More recently, managers
have become increasingly aware of the necessity to protect biodiversity
at all levels of life. Hence the recognition of subspecies based on
well-founded evidences will be important for conserving genetic
diversity below the species rank. As a mostly widespread mangrove tree,A. marina is important for the ecological health of coastal
ecosystems, especially under the prospect of global climate change.
Management efforts to protect each of the three subspecies should refer
to their distinct genetic backgrounds.