We all know Rarotonga for its blue lagoons, green mountains, and rich culture, but some of the most important parts of our environment are the ones we don’t always see: our wetlands. These watery landscapes, often overlooked, are vital threads in the delicate fabric of our natural and cultural heritage.
Wetlands are places where water meets land, including swamps, marshes, and mangroves. In Rarotonga, they may not sprawl across large areas, however the extensive network of streams and tributaries do, these are the ‘veins of the island’, and the water is the ‘blood’ that feeds all the island life. Wetlands punch well above their weight. They act like nature’s ‘kidneys’, filtering out pollutants before they reach the coral reefs that surround the island. Without them, Rarotonga’s lagoons—so central to tourism, fishing, and local life, would lose their clarity and health.
Beyond water purification, wetlands are flood defenders. During heavy tropical rains, they absorb and store excess water, reducing the risk of flash floods that could damage villages and crops. In an island environment where weather patterns are becoming more erratic, this buffer is more essential than ever.
Wetlands are also biodiversity hotspots. They cradle rare native plants and offer breeding grounds for birds, fish, and insects. For traditional Cook Islands medicine and food, many of these species are irreplaceable. And culturally, wetlands have long been part of local knowledge and practices, from harvesting taro in swampy inland areas to storytelling rooted in the rhythms of nature.
Yet, like many natural systems, wetlands face quiet threats—from land development to pollution. In Rarotonga, the push for new roads, houses or resorts can sometimes come at the expense of these ecosystems. Protecting them isn’t just about saving the environment; it’s about preserving the island’s future.
The National Environment Service (NES) is tasked with conserving and managing the ecological values of the wetlands as well as other special habitats on the island and have engaged an ecologist and entomologist Mike Bowie to assist in the assessment of the biodiversity found in sites ear-marked for potential development. He is helping staff to develop practical, robust scientific environmental compliance assessments at each proposed development site.
Below we summarise two examples of the sites the NES team assessed during June.
- 1. Sloping hill site near stream (20 June 2025)
This proposed work was for clearing vegetation and platform clearance for house site which included cutting into a 40° sloping hillside very close to a stream site. Staff recorded the significant vegetation using photos that will be loaded on to iNaturalist which is a free App that identifies species using its image recognition software, in addition to international experts that help to verify species. The stream was also assessed for aquatic life using a stream sampling net to capture species under rocks, leaf litter and vegetation. The historic disturbance at the site was evident with clearing of vegetation that led to erosion and serious silting of the stream. Silt and soil fill the gaps between the rocks where many invertebrates (shrimps, prawns, dragonfly) and other insects live. Regardless of the silt problem, a few dragonfly nymphs where found. Vegetation clearing adjacent to streams does provide some serious challenges and sloping hillsides exacerbates the issues. It this type of streamside site maintaining the vegetation on the banks and beyond helps to protect the ecological values within the stream.
- 2. Wetland, Panama next to the airport runway (24 June 2025)
This trip to the wetlands was to survey for biodiversity impacted by a 40m extension of the airport runway. Once again, we surveyed the vegetation and terrestrial insects present. The highlight was finding many dragonfly and damselfly nymphs living amongst the aquatic vegetation. These finding were supported observing three species of adult dragonfly and one species of damselfly. Not only are these native species, but both the nymphs and adults of these four species are prolific mosquito predators – dragonfly adults are known to eat more than 100 mosquitoes a day, and nymphs more than 15 mosquito wrigglers (larvae).
These ancient organisms have outlived the dinosaurs but if we continue to pollute their habitat with animal waste, then the dragonfly and damselfly may become locally extinct. Allowing cows to graze in the middle of the wetland is ecological sabotage. The nutrients from the cows’ urine and manure introduce excess nutrients into the wetland system, that can lead to algal blooms, reduced water quality and harm to aquatic life.
If we’re wise, we’ll listen to what the native inhabitants of the wetlands are telling us. In their still waters is a loud reminder that sustainability isn’t a modern invention—it’s something island communities have practiced for generations. And that harmony with nature begins with respecting the places where water and land embrace.
