The importance of science: from an invasive to an endemic species

Science is about always about making new questions, cleverly doubting the status quo. This is what makes it moves forward and improves everyone’s knowledge. Most of the time it is done in small steps, rarely as major inventions or breakthroughs.

Mauritius, a small island in the Western Indian Ocean, was once the home of the world famous dodo. Although small, because it is quite isolated, the flora and fauna evolved mostly in isolation, resulting in proportionally high levels of endemism.

Although Mauritius has one of the last places in the world where human set foot, it took no time for this rich endemic biodiversity to vanish or too become very rare and so, threatened with extinction. We know this because Mauritius flora and flora has been well-documented.

In an offshore volcanic islet 4 km north of Mauritius, named Gunner’s Quoin or Coin de Mire (Mauritius was colonised by both the French and the British, so name of many places have an English and a French version). This islets cover only 76 ha but it has some remnants of the native vegetation, and it is a stronghold of some now rare endemic species.

During a short expedition to Gunner’s Quoin, we came across a liana without leaves, having thick stem with constrictions at more or less regular intervals, which makes it resembles a line of sausages. Nearly all individuals were growing together creeping down a steep slope, looking like a green waterfall. Samples taken showed that there was no other known plant like this on Mauritius, or in the world. So it was described as a new species.

Cynanchum scopulosum, a Mauritian endemic leafless liana

Cynanchum scopulosum, a Mauritian endemic leafless liana

 

A green waterfall formed by this very rare species

A green waterfall formed by this very rare species

However, it seems that this ‘green waterfall’ was known before. Previous surveys in the 1980s and 1990s, however, saying that it was formed by an invasive species was growing there. A few years later, we also found a map from 1930s with the same information (and it also shown other places were the species was growing on the islet). This said invasive species is of the same family and superficially resembles the new endemic species.

The lesson is simple: if samples were collected and preserved in herbarium collections, the wrong field identification could have been corrected. This could have to helped to avoid this endemic species, which is restricted to this islet only, to have today a more healthy population and be less be threatened with extinction, or not threatened at all.

 

Reference cited

Florens, F. B. V.; Baider, C. 2006. On the discovery of a new endemic Cynanchum (Apocynaceae) on Mauritius with a description of its habitat and conservation status. Phelsuma 14: 7-12