Partula snail research by Justin Gerlach
My involvement with Partula conservation dates back to 1992 when I studied the ecology of Euglandina in order to answer fundamental questions about its biology and impacts. My Euglandina research hoped to find some way of controlling the predator, but sadly I had to conclude that it is there to stay. During that research I traveled to Polynesia to investigate the situation in the islands and to rescue any last surviving Partula. I concentrated on the island of Raiatea, one of the last to be invaded by Euglandina and the centre of Partula diversity. Before Euglandina arrived in about 1984 Raiatea had been home to 33 species of Partula. In 1992 I collected the very last surviving animals; 88 snails belonging to just three species!
The last survivors (1992):
 |
 |
 |
| Partula faba | Partula navigatoria | Partula labrusca |
Partula faba - the most widespread Raiatean species and the first Partula to be described (from a shell collected on Captain Cook's first round-the-world voyage). This ought to have been an adaptable species but it never thrived in captivity and the last one died in February 2016.
Partula navigatora - currently secure in captivity. For many years this species was misidentified; what a species really means in this group is not as easy a question as it may sound. This was addressed by my project completing Henry Crampton's great Partula work
Partula labrusca - a little known species from a strange high-altitude plateau.
Sadly high-altitude Partula have always been difficult to keep and the last descendant of my labrusca died in 2002, adding another name to the list of Euglandina's victims.
My renewed interest in these icons of extinction is four-fold:
2. What enables some Partula to survive, and how can we use that to save the remaining species? Research into these questions is producing very signficant results, meaning that we may now be in a position to re-establish species in the wild.
3. How will Euglandina and the new additional threat of a predatory flatworm respond to changes in the environment- are such changes opportunities or further challenges?
4. How will climate change affect the situation?
Climate change may be particularly significant at high-altitude sites and these are of exceptional interest. In the higher sites surprising discoveries still remain to be made. When I collected on Raiatea I did not quite rescue the last survivors for in 2006 the botanist Jean-Yves Meyer discovered three individuals of a new species of Partula on the top of the highest point of the island. This almost inaccessible peak still supports what must be a tiny population of Partula meyeri, or at least it did in 2006. Has Euglandina found them since then? If not how far away is it? How is the ecosystem coping with changing climate patterns? These are some of the questions I have been addressing, including with field research in 2017 and in 2023.
Partula taxonomy
