Galapagos Rock-Purslane
From Galapedia
| Galapagos Rock-Purslane | |
| Image:Galapagos Rock-Purslane.jpg | |
| Habitat: | arid and transition zones on San Cristóbal |
|---|---|
The beautiful Galapagos Rock-Purslane (Calandrinia galapagosa) plant is endemic to just one island, San Cristóbal, and is highly vulnerable due to the presence of goats. To counteract its declining populations, the Charles Darwin Foundation (CDF) have made this species part of the threatened species project that is currently underway throughout Galapagos.
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Unique to Galapagos
Galapagos Rock-Purslane is a perennial herb that grows to about 60 centimeters high. It is woody at the base of the plant but has succulent stems and leaves. The beautiful flowers have five delicate and translucent petals, each about one centimeter long.
There are at least two varieties:
- One with white flowers and green leaves
- One with pink flowers and purple leaves
This species grows in the arid and transition zones, restricted to San Cristóbal Island, with a few plants also found on Kicker Rock, off the north coast.
Vulnerability
Galapagos Rock-Purslane is listed as Critically Endangered on the IUCN Red List. Populations have been greatly reduced by feral goats on San Cristóbal; however other causes are not understood.
In 1998, only two populations were known to survive on the main island, one of which was fenced in 1993, protecting about 500 plants. The other population, in the north-east of the island, comprised scattered small groups of plants on the walls of small craters, where they were inaccessible to goats.
CDRS research activities
Galapagos Rock-Purslane was chosen as one of the CDF's first threatened species, because it is endemic to just one island and the species is not very well understood.
A complete survey of its distribution began in 1998. The known populations of this plant were surveyed and new ones found. It was rediscovered inhabiting lava fissures at Sappho Cove on the north coast of the island where it was first discovered almost 100 years ago but had not been seen since. Several other small groups of plants were found near both south and north coasts of the island.
Each population showed evidence of damage by goats or insects, including a stem-boring fly larva, which seems to be a species new to science. Further fencing was required to protect additional populations from being eaten by the goats.
Recently, CDF scientists have been investigating genetic variability between populations and interbreeding between the two known varieties.
Monitoring is now needed to keep track of the status of the remaining populations. This information will help the CDF to plan for the future conservation and restoration of this beautiful endemic species.
