Valuing indigenous biodiversity in the freshwater environment

Biosecurity incursion response decisions require timely, high quality informationinvolving science and economics. The value of the impact on indigenous biodiversityis a key aspect of the economics typically involving cost-benefit analysis. Thehypothetical incursion of Biosecurity New Zealand’s top priority weed hydrilla(Hydrilla verticillata) in a typical New Zealand lake (Lake Rotoroa otherwise knownas Hamilton Lake) elicits dollar values of impacts on indigenous biodiversity in afreshwater environment. Using the stated preference tool, Choice Modelling, theexperimental design was maximised for efficiency of Willingness to Pay (WTP)estimation. The survey method of community meetings of four population samples atvarying distances to the incursion site is a cross between a mail survey and anindividual interview survey. Results show an efficient design with minimal samplesize and biodiversity attributes that have values statistically different from zero butnot statistically different between locations.