Results and reflections

Forest monitoring in the South Pacific – Blog #8

With an eye to the future, our fieldwork in French Polynesia ended last week with project lead Yadvinder Malhi joining us for a whirlwind tour of Moorea and Tetiaroa. We visited the plots, met with project partners and explored potential future research opportunities – a wonderful way to reflect on our findings to date.

Exploring the Trois Cocotiers trail – stunning forest and waterways below the dramatic peaks and ridges of the Opunohu Valley.

An enormous mape (Inocarpus fagifer) tree with its unusual trunk

Opunohu Bay at sunset – very few buildings or people to be seen

On Tetiaroa we were joined by Neil Davies and Hervé Bossin of the Tetiaroa Society, as well as resident Executive Director, Frank Murphy. We had plenty to discuss during Yadvinder’s brief visit, including future expansions of the forest plots, the evolution of the Tetiaroa Island Digital Ecosystem Avatar (IDEA) project and the intersection between long term ecological monitoring and innovative management plans like mosquito control.

Hervé Bossin (Institut Louis Malardé) explaining the use of mosquito traps to monitor the effectiveness of a successful eradication program on Onetahi.

Yadvinder, Heipoe, Neil Davies (Gump Station, Moorea) and Hervé Bossin (Institut Louis Malardé) discussing future monitoring opportunities on Tetiaroa.

The final ‘reveal’ of our findings was held in conference room at The Brando, and a few adventurous hotel guests even abandoned their cocktails to join us. The history and trajectory of each type of forest is not entirely clear, but initial results hint at past Polynesian uses and plantings on different motu, and suggest coconut trees are recruiting less well in some forest types than others. These results will be uploaded to ForestPlots.net and future tree censuses on Tetiaroa will contribute to the global picture of forest growth and change over time.

Final presentation to the Tetiaroa Society and guests of The Brando hotel. Yadvinder sharing insights into the global significance of the forest plot network, and exciting ideas for future studies on Tetiaroa.

Final presentation to the Tetiaroa Society and guests of The Brando hotel. Heipoe explaining our monitoring methodology with some videos.

Composition of Tetiaroa forest plots – species composition and number of stems per plot scaled to 20m x 20m. The forests differed greatly and each site was dominated by one particular species, with the exception of A’ie.

Heipoe used timelapse footage and videos to demonstrate how we’d collected all the data – over the last few months she has become an expert in the methodology, and well and truly exceeded her goal of improving her English! Finally, Yadvinder captured everyone’s imagination by demonstrating the potential of 3D laser scanning of forests, an opportunity on Tetiaroa which would yield much more precise growth measurements (and just be insanely cool)!

Pink tape marks the entrance to plot ‘TET06’ on Tiaraunu

Yadvinder observed that the large stands of similarly sized tamanu (Calophyllum inophyllum) trees in plot TET06 hints at waves of germination over different years.

Hervé and Heipoe by a mosquito trap within plot TET06. The density and nature of vegetation is a useful predictor of mosquito abundance, so there is much to be learnt by co-locating our monitoring sites.

The turtle season has started and Tetiaroa is a popular spot for nesting green turtles. Nests like this one are marked and monitored.

From the air, the lake on Rimatu is enormous – and the associated freshwater lens has a major influence on the vegetation across the entire motu.

Signing off with Mayalen Zubia, Jean-Yves Meyer (not pictured) and Yadvinder Malhi on our final evening. With lots of ideas for future student projects and ongoing collaborations in this beautiful island nation.

Our final day in paradise was truly that… punctuated by strong breezes and a slight concern our little aircraft wouldn’t be able to land! Everything came together in the end and Yadvinder and I were glad to be able to meet up with Mayalen Zubia from Université de la Polynésie française and Jean-Yves Meyer briefly in Tahiti before heading to the airport.

Mayalen has plans to involve many more of her students in forest monitoring and the Tetiaroa Society share her vision of undergraduate interns visiting Tetiaroa each year for their placements. Despite rushing to deliver the opening address at a conference dinner, it was lovely to share a final Hinano (THE Tahitian beer!) with Jean-Yves as well. He even rescued our leaf samples at the very last minute (thank you, thank you!), to help return them to Oxford safely for nutrient analysis.

They and many others deserve enormous thanks for supporting us and joining in this research, and all that’s left to say is – maururu roa – merci beaucoup – thank you very, very much!