A simple search in the Cook Islands Biodiversity database shows Cook Islands has 16 different types of Palms, with the majority being introduced for ornamental purposes.
Two of the 16 have been identified as native, including the common coconut palm.
The other one has long been thought to only be found on Mitiaro, hence the name Mitiaro fan palm. The scientific name is Pritchardia mitiaroana, and it is locally known as the Iniao.
The Iniao is a smallish palm usually from 4 to 6 metres in height, with a trunk typically 35cm in diameter when mature. The crown of the tree has up to 25 fan shaped fronds, and can produce fruits of between 5 and 7mm in diameter that become dark brown or black when ripe..
Previously, the Iniao was thought to be endemic (only found) in Mitiaro.
However, several clusters of fan palms found in the Tuamotu islands (in Niau and Makatea) in French Polynesia were reclassified in 2007 as the same species by an American palm enthusiast, Donald Hodel.
So how could these palms be found in these remote locations? How are they connected?
It is well-known that our Polynesian ancestors were expert navigators and voyagers.
Dr Jean-Yves Meyer from the Government Research Division of French Polynesia has one theory, based on ancient Rarotongan stories and oral traditions recorded in the Journal of the Polynesian Society by a gentleman by the name of Stephenson Percy Smith (no relation to the author of this article!) in 1899.
This oral history stated that there was a strong “sea route” between Niau (formerly known as Fakaau, in the Tuamotus), the southern Cook Islands and the Marquesas.
Because of this frequently used route, it could have been quite possible that Polynesian voyagers could have transported the endemic Pritchardia between these three islands.
Dr Meyer carried out a survey of the Tuamotuan Pritchardia on Niau, as well as in Makatea, in 2007 and suggests there were about 1000 individuals including numerous juvenile plants present on Niau at that time. Makatea had fewer, around 100 individuals, due to the destructive phosphate mining industry causing deforestation.
Baseline numbers for the Iniao in Mitiaro, based on a 2019 Ridge to Reef project survey, was 491 mature palms. This was up from an estimate of 395 in 2017 by Gerald McCormack from the Cook Island Natural Heritage Trust. Additional trees in 2019 were counted through the use of drone technology.
So back to whether the Iniao is in fact endemic to Mitiaro: The palm journal in which Hodel published his 2007 paper, stating that the palms in the Taumotus and Mitiaro are the same, is apparently not peer-reviewed.
This means that other palm experts may not have been consulted in this opinion. Therefore, to officially determine the Iniao’s relationship to the palms of the Tuamotus once and for all, a genetic study of samples from the three islands would be a logical next step.