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Coconut plantations have led to deforestation on over 80 per cent of Pacific atolls, with coconut palms now covering over half of their forested areas.
The first detailed maps of coconut farming and the resulting deforestation on Pacific atolls were unveiled by Nature Conservancy and UC Santa Barbara. This study of vegetation maps of 235 of 266 pacific atolls was published in Environmental Research Letters on December 4, 2024.
An atoll is a ring-shaped coral reef, island or series of islets. Over the last 200 years, the pervasive land cover change profoundly altered ecosystems and hydrologic resources, affecting atoll communities’ resilience to climate change and other environmental stressors.
Atolls were extensively targeted for coconut plantation development in the Pacific. The analysis revealed for the first time the vast legacy of colonial copra (dried coconut kernel used for coconut oil extraction) production across nearly every Pacific atoll.
Planting efforts by colonial enterprises changed the coconut palm from a valued subsistence crop to a monodominant export crop on Pacific atolls.
Coconut palms surpassed native broadleaf trees in terms of canopy area. A little over half of these coconut canopies occur in monocultures indicative of plantation agriculture and drastic ecological changes.
Coconut presently covers 58.3 per cent of the mapped atolls' total forested area and 24.1 per cent of their total land area. This loss of unique atoll ecosystems exceeds even oil palm-driven deforestation.
The study found that a "history of intensive copra production increased an atoll's present-day coconut canopy fraction by an average of 32.1 per centage points across rainfall levels”.
Coconut palms are predominantly found on large, wet islands, indicating their significant water consumption and their ability to exhaust essential groundwater supplies. The spread of coconut plantations also came at the expense of native vegetation critical for wildlife habitat, nutrient cycling, and soil formation, the authors of the study noted.
Even on atolls, where planting and harvesting ceased decades ago, former coconut plantations persist and exclude competing vegetation. This helps maintain coconut monocultures as a consistent vegetation type when there is no human interference.
The prevalence of coconut palms varied widely across atolls, island groups and nations. Groups with relatively high coconut canopy fractions on their atolls include Tokelau (73.1 per cent), the Solomon Islands (66.2 per cent) the Cook Islands (60.0 per cent), Tuvalu (58.2 per cent), and Fiji (56.3 per cent).
Some island groups support relatively small coconut canopy fractions on their atolls, such as New Caledonia (<0.1 per cent) and the Phoenix Islands of Kiribati (15.8 per cent).
Coconut plantations on Pacific atolls are no longer expanding at a significant rate, the findings showed. Over the last half-century, adverse market conditions have dissuaded the maintenance of plantations, resulting in numerous once-productive atolls being filled with large areas of unprofitable, aging palm trees, according to the report.
Addressing these abandoned plantations is an opportunity to restore native broadleaf forests and conserve essential water resources, the authors suggested.
On atolls with active coconut plantations, they added, diversified agroforestry approaches could allow cultivators to produce coconuts, while receiving the ecological benefits of broadleaf canopy trees.
A study published in Restoration Ecology March 16, 2021 found that if broadleaf forests, shrublands and grasslands cover 55 per cent of a coral island, critical seabird-driven ecosystem functions, such as nutrient delivery fully recover after the eradication of invasive rats.
Throughout the study region, 64.8 square kilometres of coconut palm on 929 islands would need to be converted to broadleaf habitats to meet the specified threshold. Along with the removal of invasive predators, this 55 percent reforestation target could help island managers address water and nutrient shortages.
