Science Centres: Aquatic Biodiversity and Biosecurity

The freshwater eelgrass, Vallisneria spiralis, commonly used in aquaria, has recently taken hold in Northland, Wellington, Wairarapa, and Marlborough. Although it doesn’t move around easily, it is extremely invasive once planted, forming dense mats in fast-flowing waterways. It is not included on the current NPPA list.

The National Pest Plant Accord (NPPA) is a cooperative agreement between regional councils and government departments with biosecurity responsibilities to prevent the sale and/or distribution of specified pest plants within New Zealand.

Because some pest species haven’t made it on to the NPPA list, or have only recently begun to show weedy tendencies, the NPPA is currently undergoing a review. As part of this, Biosecurity New Zealand has commissioned NIWA to provide a framework for deciding which plant species should be included in the NPPA. The framework includes criteria to evaluate the level of impact a plant may have, and its risks to economic, health, environmental, and cultural values.

A panel of seven botanists from various Crown agencies, including NIWA, Biosecurity New Zealand, the Department of Conservation, and the QEII Trust, have assessed 171 plants or plant groups for inclusion in the NPPA, based on a range of criteria. This has included assessments of the weedy potential of aquatic plants by use of NIWA’s weed risk assessment model.

Public submissions on the assessments have been received and will be considered in the final decision on which species to include on the NPPA list.