Fiji, Vanuatu, Solomon Islands, PNG at risk of invasive plant

Transcript

A new study may help halt the advance of an extremely invasive plant, which has decimated two thirds of the vegetation of French Polynesia.

The South American miconia tree is known as the 'green cancer', and 91 countries have been identified as at risk of colonisation, with parts of Fiji, Vanuatu, the Solomon Islands and Papua New Guinea identified as particularly high risk.  

Researchers from the University of Alcalá in Spain hope maps they've produced of vulnerable areas will help prevent the plant spreading.  

Bridget Grace spoke with Researcher, Noelia González Muñoz from INRA - the French National Institute for Agricultural Research - and started by asking why the plant has been so sought-after in botanic gardens worldwide.

Noelia González Muñoz: It's popular because it is beautiful, it's a tropical tree species.  It reaches up to ten metres and quite beautiful because it has huge leaves which are green on the top with white lines and the in other side they are purple. So it's really colourful, and I think that's why a lot of people have introduced this plant out of it's native range all around the world.  

Bridget Grace: I understand that the plant has been called by some the 'green cancer', why is this?

NGM: Because it is really, really, extraordinarily invasive.  When this plant arrives to a suitable area, it spreads and it can colonise all the area, it forms monospecific stands, closed forest, and anything else can't grow.

BG: Why did you decide to look at this plant, and also what were the findings of your study?

NGM: We decided to work with this plant because it's a very, very interesting case among biological invasions.  It's one of the one hundred worst invasive species of the world.  So we decided to work with this species and create maps to prevent the expansion of this species all around the world.  And which are our main findings were, we create a map in which we identified the worldwide areas most suitable for the plant.  Then that can alert people to prevent the introduction and expansion of the species in new areas.

BG: How many areas that you've found with the map, that is plant could move into?

NGM: We identified 91 countries in the world which are suitable areas for this species and also up to 420 islands.  We also identified up to 154 protected areas.  

BG: Do you know what impact this plant has in the Pacific?

NGM: Overall there are a lot of studies focused on French Polynesia, they've identified up to fifty endemic plant species that are under risk of disappear because of the presence of miconia in Tahiti.  And also it provokes very negative impacts on the soils.  

BG: I think in French Polynesia it's considered the worst plant plague in history?

NGM: The case of the invasion of miconia in French Polynesia is very, very special because we know specifically when the plant was introduced and we know it was around 1973 and where it was introduced, it was in a private garden and from there it spread and colonised two thirds of the island.  

BG: In terms of if there was someone that was looking at the maps that you've produced, and they saw their area was potentially at risk from Miconia, what could they do to prevent the plant from spreading?

NGM: The first thing would be to not introduce the species there and the second would be to check if it has been introduced and in that case it could be interesting to look at the botanic gardens or private gardens and if it is expanding.  Because if the area is suitable and the species is already there, we can have another situation like in Tahiti.