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Cook Islands Statement at the Whales in a Changing Ocean Conference, Vava'u, Tonga

Invasive alien species such as Spathodea campanulata (African tulip tree) threaten biodiversity in the Pacific islands as well as the economic, social, and cultural wellbeing of Pacific peoples. Despite the potential magnitude of these threats, our scientific understanding of the ecology and management of the African tulip tree is nascent. In this paper, we use data from novel surveys of households and communities to document the direct and direct impacts of African tulip tree in Fiji, focusing on those impacts which may be monetised. We use the same data to describe current management approaches and then describe a state-of-the-science, ‘‘integrated’’ management approach that employs different strategies for trees of different ages and sizes. These two approaches are then compared in a comprehensive cost–benefit analysis. We find strong arguments for pursuing the integrated management approach, which derives monetised benefits of $3.7 for each $1 spent. However, the less costly current approach is also strictly preferred to the baseline, ‘‘do nothing’’ approach, with monetised benefits of $2.7 for each $1 spent. Results of this analysis clearly show that managing African tulip tree is cost effective, even without explicitly considering biodiversity, culture, and other non-monetised benefits of control.

Taro (Colocasia esculenta (L.) Schott) plays a prominent role in the economies and cultures of Pacific Island countries such as Fiji. Unfortunately, taro is highly susceptible to invasion from taro beetles, which burrow into the corms and weaken the plants, rendering them unmarkable and prone to rot. Papuana uninodis Prell, an invasive alien species that is native to the Solomon Islands and Vanuatu, was first reported on Viti Levu (Fiji's largest island) in 1984. Since that time, taro production on Viti Levu has fallen substantially. In this paper, we employ data from surveys of households and communities to document the impacts of P. uninodis on Viti Levu. We then identify three management approaches-chemical controls, cultural controls, and switching from taro to another staple crop-and conduct a cost-benefit analysis of each. We find strong arguments for pursuing chemical control, which derives a net present value of monetised benefits of about FJ$139,500 per hectare over 50 yr, or >FJ$21 for each FJ$1 spent. Still, any of the three management options is more efficient than no management, even without any attempt to quantify the benefits to biodiversity or forest protection, underscoring the value of actively managing this invasive alien species.

Invasive species pose an enormous threat in the Pacific: not only do they strongly affect biodiversity, but they also potentially affect the economic, social and cultural wellbeing of Pacific peoples. Invasive species can potentially be managed and their impacts can potentially be avoided, eliminated, or reduced. However, neither the costs nor the numerous benefits of management are well understood in the Pacific. Thus, we undertook cost-benefit analyses (CBAs) of managing five species that are well established on Viti Levu, Fiji: spathodea campanulata (African tulip tree), herpestus javanicus (small Asian mongoose), papuana uninodis (taro beetle), pycnonotus cafer (red-vented bulbul), and merremia peltata (merremia vine). These CBAs are informed by extensive survey data that record the incidence, management, and impacts of five species in Fiji. Wed find that the most cost-effective management option varies by species, precluding a universal solution. Nevertheless, the benefits of management often exceed the costs of management by a wide margin, arguing for a more concerted effort to control the spread of invasive species in the Pacific.

PACC reports

Reports from the PACC project