Study of alteration of terrestrial ecosystems functioning by three introduced species - update March 2026
Main Objectives:
This mission aimed to launch a litter decomposition protocol across 30 sites distributed among 10 motus, in order to assess the impact of the coconut palm (Cocos nucifera) on the functioning of Tetiaroa's terrestrial ecosystems. It also sought to maintain the monitoring of the Tahinu tree (Heliotropium foertherianum) flowering cycle as part of a study on pollinating bees, and to deploy a surveillance system to study the effects of the mosquito Aedes polynesiensis on the reproductive success of the Brown booby (Sula leucogaster), through the installation of traps and cameras across the motus of Tahuna Iti, Tiaraunu and Horoatera.
Summary of field activities :
A litter decomposition protocol was launched across 30 sites distributed among 10 motus (excluding Honuea and Onetahi). At each site, environmental parameters were recorded using multi-parameter probes (moisture, conductivity, temperature, pH), and photographs of canopy openings and litter cover were taken. Twelve litter bags made from Pisonia grandis leaves and 22 individual leaves of the same species were deployed per site to monitor decomposition rates and observe terrestrial decomposers. Sampling is scheduled at 10, 30, 60 and 90 days.
In parallel, batteries and SD cards were replaced in the 10 camera traps positioned in front of Tahinu trees (Heliotropium foertherianum) to ensure continuity of the flowering cycle monitoring, as part of a study on pollinating bees.
Finally, 73 flower-pot traps were installed on Brown booby nests spread across Tahuna Iti, Tiaraunu and Horoatera, along with 10 cameras per motu to capture potential behavioural disturbances caused by mosquito pressure (one-minute videos every 5 minutes over 24 hours).
Preliminary results :
No preliminary results are available at this stage of the mission.
Perspectives :
A second mission is planned for March 2026 (Day 30) for the first collection of litter bags and Pisonia grandis leaves, in line with the established protocol. Data from the mosquito traps and cameras will also be retrieved and analysed to produce an initial assessment of mosquito pressure on Brown booby nests.