Measuring ecosystem services and assessing impacts

Marine species and habitats provide many ‘ecosystem services’ that are of value to people and communities, such as food, coastal protection, improved water quality and nutrient cycling. We developed ways to measure two ecosystem services:  

1. The provision of refuge habitat that supports young finfish and shellfish.  
2. The removal of pollutants, specifically nutrients, from our coastal waters.  

We have predicted and mapped variation in the amount of refuge habitat in the Hauraki Gulf and in the Marlborough Sounds. The work in the Hauraki Gulf has been validated with survey data from 57 sites.  

Excessive nutrients are a problem for coastal ecosystems, and it is important to identify areas that can process or remove nutrients efficiently. Denitrification is one such process that removes nitrogen, but it is difficult and expensive to measure. We have found environmental measures that correlate well with denitrification, and these can be used to predict areas where high levels of nutrient removal occur. We have developed maps of the nutrient removal service for two bays near Auckland: Whitford and Wairoa.  

Our results will be useful for regional government agencies seeking to identify marine ‘hotspots’ of ecosystem service delivery that require protection. We worked closely with other Challenge researchers to clarify the links between New Zealanders’ social and cultural values for marine areas and the ecosystem services they provide.

You can read more about the kinds of services that ecosystems provide on NIWA's website.