Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

PRISMSS Invigorates Pacific Weed Biocontrol

Invasive species are the leading driver of biodiversity loss in the Pacific, negatively affecting ecosystem resilience, ecosystem services, and future ability to adapt to climate change. In the past the major gap in invasive species management in the Pacific has been adequate, on-the-ground operational action. Now a new initiative has been launched by the Secretariat of the Pacific Regional Environment Programme (SPREP) to address this gap.

“The Pacific Regional Invasive Species Management Support Service, which is known as PRISMSS, will significantly increase both the quantity and scope of management operations in the region,” explained David Moverley of SPREP. “PRISMSS will provide management support for on-the-ground invasive species actions, through streamlining and coordinating activities and providing ready access to invasive species management experts who are leaders in their respective fields,” he added. PRISMSS has five regional programmes, which are described below.

Protect Our Islands focuses on national and inter-island biosecurity, and the early detection of and rapid response to new incursions.This is critical, since biosecurity is the first line of defence against invasive species arriving and establishing in a new destination. Pacific Biosecurity, based at Victoria University of Wellington, is the lead PRISMSS technical partner for this regional programme, with support from the Pacific Community (SPC), the mandated coordinator for national biosecurity in the Pacific.


War on Weeds targets the management of high-risk, low-distribution weed species, where the objective is eradication or containment. Weeds thrive on disturbance, and so their harmful impacts are exacerbated by tropical cyclones, strong winds, drought and fires, all of which are increasing in severity due to the changing climate. SPREP is the lead PRISMSS technical partner for this regional programme.

Natural Enemies – Natural Solutions deals with widespread weeds, where the only safe, cost-effective and sustainable way of managing them is by utilising their natural enemies (biocontrol). Natural enemies have been established on 25 weed species in 17 countries in the Pacific, and there are many opportunities for spreading existing agents available in the Pacific to new countries, introducing agents available outside the Pacific, as well as developing new options for the Pacific. Manaaki Whenua – Landcare Research is the lead PRISMSS technical partner for this regional programme, with assistance provided by tropical weed biocontrol expert Michael Day (Biosecurity Queensland).

Predator Free Pacific covers the removal of mammalian predators from islands.Sixty Pacific islands have had predators, such as rats, removed. Island Conservation is the lead PRISMSS technical partner for this regional programme, the only charitable organisation solely dedicated to removing invasive species on islands to prevent extinctions. They are supported by BirdLife International, who, with their partners, have eradicated introduced vertebrates from over 30 tropical Pacific islands.

Finally, Resilient Ecosystems-Resilient Communities supports the ecological restoration of priority areas. Threatened species and ecosystems in the Pacific often exist within high-value areas on larger islands where invasive animals and invasive plants will continue to be a threat. A site-led approach to manage multiple invasive species and re-introduce lost native species and ecosystem structure over a longer period of time is therefore needed. SPREP is also the lead PRISMSS technical partner for this regional programme.

PRISMSS was officially launched in July, and during October and November a 5-week Programme Management Course was held at SPREP’s headquarters in Apia, Samoa. “This enabled participants from across the Pacific to receive training to plan and manage an invasive species programme of work focused on the regional programmes under PRISMSS,” explained David. Lynley Hayes and Michael Day ran a module covering the use of weed biocontrol for 18 participants from 10 counties and five SPREP staff. “In recent decades biocontrol has become somewhat of a forgotten tool in the Pacific. But the tide appears to be turning, with New Zealand enabling recent activity in the Cook Islands, and a project currently underway in Vanuatu, leading to the development of new agents for key weeds in the region,” said Lynley.

Michael Day showing trainees the giant sensitive plant psyllid

The workshop participants were surprised to learn about successful weed biocontrol programmes in their countries, of which they had no prior knowledge. Because successful programmes result in weeds becoming low incidence, out of sight can soon become out of mind, and the previous importance of these weeds and the biocontrol intervention taken are forgotten within a generation. This meant that quite a bit of searching was needed to find suitable sites for the field trip component, since the weed targets are now much less common.

Agents were released in Samoa in the 1980s and 1990s against giant sensitive plant (Mimosa diplotricha) and lantana (Lantana camara), respectively. However, eventually a small patch of the former, and three plants of the latter, were located, and the participants were able to familiarise themselves with the psyllid (Heteropsylla spinulosa) on giant sensitive plant and leaf-mining beetle (Uroplata girardi) on lantana, which have provided excellent suppression of these weeds. “By the end of the workshop there was considerable excitement and enthusiasm for the prospect of delivering more such successes in the Pacific,” said Lynley.

Adult psyllid

With the training over, the focus now will be on developing new biocontrol programmes in 2020 for Niue, Tonga, Tuvalu, Marshall Islands, and Wallis and Futuna, all of which have secured funding for this work. It is anticipated that funding will also be secured soon to enable additional Pacific Island countries and territories to get new projects underway. At the outset, in-country surveys will be undertaken to assess which weed targets may be suitable for the natural enemies approach and any biocontrol agents already present. Workshops will then be held so that people with knowledge of, or interest in, weeds in-country can consider the relative importance of each species under consideration. This information will be combined with the feasibility of biocontrol and the likelihood of success for these weeds so the workshop participants can identify and agree on the top priorities for action.



For Natural Enemies – Natural Solutions: Lynley Hayes -

PRISMSS was established in 2019 with the assistance of the Global Environment Facility (GEF) project “Strengthening national and regional capacities to reduce the impact of invasive alien species on globally significant biodiversity in the Pacific”. GEF and the European Union-funded PROTEGE project are funding the development of new national biocontrol projects mentioned above. The New Zealand Department of Conservation is also supporting the development of PRISMSS. The New Zealand Ministry of Foreign Affairs and Trade is funding weed biocontrol projects in the Cook Islands and Vanuatu.