Plants Endemism In Mauritius
(Author: Dr. Rafic Dulymamode)
Islands have always fascinated Man for various reasons. To the biologist, islands are natural laboratories where one can study evolution at work. These isolated areas situated far away from continental masses present different set of conditions conductive to speciation. No wonder then that such regions harbour a rich component of endemics in their biota. This is particularly true for volcanic islands such as Hawaii, Socotra and Mauritius.
What are endemics? Endemics are taxa occurring in a single restricted geographical area. Endemism has a different meaning in everyday use especially in describing diseases where it is equivalent to the biogeographic term indigenous (native). Two types of endemism are recognised; neoendemics are evolutionary young taxa which have not yet been able to spread to other areas, and paleoendemics are geographically restricted taxa which once were more widely distributed. Neoendemics can further be differentiated into schizoendemics, patroendemics and apoendemics based on cytotaxonomic data namely chromosome number and ploidy level. In general, neoendemics greatly outnumber paleoendemics. The percentage of endemics species in a flora is usually proportional to the degree of isolation of the area of the involved, a factor measured as the distance from other similar areas and/or the length of time of isolation.
We do not have all the information to categorize the Mauritian plant endemics but we know that over 300 species of the flora fall in this group. Amongst the Mascarene Islands, Mauritius has the highest proportion of endemism; 45% (311 species) compared to 35% (189 species) in reunion and 35% (47 species) in Rodrigues. The botanical value of a country's flora depends on its component of endemism. We are fortunate to have such a rich flora but must be vigilant as in many cases these species are represented by very small populations. We must therefore spare no effort in our pledge to safeguard the long-term survival of these plants. The present endeavour deserves all our encouragement and congratulations as it is one of these efforts towards this goal.