Valuation of biodiversity and ecosystem services to improve spatial management of near-shore marine areas in New Zealand

Abstract

Ecosystem-based management (EBM) is a holistic approach that is most reliable for achieving sustainability of complex, coupled social-ecological systems. An EBM approach to marine fisheries can be put in practice by implementing marine reserves and Customary Protection Areas (CPAs) in addition to conventional fishing regulations (input and output controls). Marine reserves are ‘no-take’ areas where all fishing is completely banned; whereas CPAs provide a flexible mechanism that enables local indigenous people and communities to enact responsibilities and protect their long-term interests. Spatial conflicts between these additional management tools with existing uses (especially fishing) and between the tools themselves have been a major obstacle to practical application of EBM. This has resulted in conflicts of interest and a ‘race for space’ for prime sites chosen for marine reserves and CPAs.

This thesis reports analyses of testimony from forty interviews and four focus groups involving key stakeholders to two case-study marine ecosystems in New Zealand. The results show that polarisation of goals and values, the race for space, and social conflicts have actually been induced by perceived declines in fish stocks and biodiversity. Marine reserves are perceived to be more reliable than CPAs (Taiāpure and Mātaitai) for protecting existing and restoring declining biodiversity and fish stocks. Biodiversity is highly coveted for its own intrinsic value and for long-term human benefits. However, Māori have vigorously opposed marine reserves due to the concern over the cumulative loss of traditional fishing grounds, the loss of opportunity to gain control over these areas, and the threat to cultural practices. Recreational and commercial fishers have opposed any greater restriction that has potential to accumulatively threaten their fishing. These fishers tend to support taiāpure in a way that forms a coalition with its proponents to make more effective opposition to a marine reserve that has greater impact on fishing. Impact assessment tests are insufficient for making sound decisions about the allocation of space in marine areas. Therefore, information about the large public’s preferences for the trade-offs between reductions in current uses and a greater chance of achieving sustainability induced by implementation of marine reserves and/or CPAs are needed.

An online survey-based choice experiment was implemented using 1000Minds software to obtain information about relative values held by the public towards four major competing uses of marine resources (i.e. socio-ecological attributes) under debate. They include commercial fishing, recreational fishing, Māori cultural management, and biodiversity. A tax attribute was also included in the choice experiment to allow estimation of values in dollars. One thousand and fifty five New Zealanders participated in the choice experiment. Each individual respondent made on average twenty seven choices. Each choice puts the respondent in a situation where he or she must trade-off one better level of an attribute of a near-shore marine area for a better level of another attribute. Data from choices made allow estimation of a complete set of ‘part-worth utilities’ for each respondent using a linear programming routine. The results reveal that improved biodiversity is, on average, the change most valued by the general public, whereas restoring Māori cultural practices is roughly as important as maintaining the current relatively light restrictions on recreational and commercial fishing. Logistic regression analysis identifies some of the influences on the variation across respondents in the relative values of each socio-ecological attribute. This information allowed estimation of population-weighted average utility values. These values were used to estimate net changes in welfare from implementation of various management scenarios currently under consideration. The results suggest that any management alternative that restores either biodiversity or both biodiversity and Māori culture will yield a substantial welfare gain.

The functional relationship between changes in taxes and utility values estimated from the choices made by each respondent allows estimation of willingness to pay (WTP) for any change in any other attribute. WTP constitutes the dollar value to the respondent of such a change. The results are highly correlated with those based on the utility values discussed above. Annual population-weighted WTP is estimated at roughly NZ$224/household (NZ$370 million for the nation) or NZ$128/household (NZ$212 million for the nation) for improving biodiversity from poor to good or from poor to medium condition, respectively. Mean population-weighted WTP to maintain Māori culture or current light restrictions on commercial or recreational fishing is almost half as large. By applying these WTP estimates, an annual net benefit equivalent to roughly NZ$165 million or NZ$66 million at a minimum can be generated by policy that either restores biodiversity or both biodiversity and Māori culture. With dollar values, it is possible to suggest that there is potentially sufficient money to buy back commercial quota required for the policy implementation, while still making New Zealanders ‘economically’ better-off.

The results from this general study provide a strong justification for the joint implementation of marine reserves and taiāpure (or mātaitai in areas of greater cultural significance for Māori). This joint implementation in the form of Marine Protected Areas (MPAs) or more broadly Biosphere Reserves offers perhaps the best chance of success in achieving sustainability of the complex, coupled social-ecological marine systems and resolving the race for space over the long-term. These results provide support for implementing New Zealand’s MPAs Policy, which has been delayed for almost a decade.

Choice experiments are a developing type of valuation technique that can generate information about social preferences for aspects of competing policy options and contribute to improving the efficiency and sustainability in resource allocation. However, there is still much to be learned about the limitations and possibilities of choice experiments, so future applications should routinely include methodological experiments as part of their study design. Both monetary and non-monetary metrics may be used to complement each other because each has its own strengths and weaknesses. For instance, dollar values are easier to interpret, but estimating them requires more effort and care about associated uncertainty. For guiding public policy, results from choice experiments or any economic modelling need to be complemented by those from biological/ecological and sociological studies to achieve a sustainable and desirable future.