What are Ecosystem Services?
‘Ecosystem Services’ are the benefits people receive from the natural environment and well-functioning ecosystems. When some people look at a wetland they see plants and trees growing around a waterway, with possibly birds in the trees and fish in the water. They may see benefits for nature, but won’t necessarily understand that people also receive benefits (referred to as services) from well-functioning ecosystems. For example, wetland ecosystems are doing much more than meets the eye.
Ecosystem services can be split into four categories (examples given for the benefits wetlands provide):
- provisioning services (products obtained e.g. food and timber)
- supporting services (e.g. nutrient cycling and soil formation)
- regulating services (e.g. purification of water, flood control or climate control)
- cultural services (e.g. spiritual enrichment, recreation and aesthetic experiences)
Collectively these benefits from well-functioning ecosystems are essential for providing clean water, pollinating crops, delivering economic wellbeing, and ensuring the social and cultural wellbeing of people and communities.
What was the purpose of the Living Water trial of an Ecosystem Services approach?
Living Water commissioned Manaaki Whenua Landcare Research to test the usefulness of an ‘Ecosystem Services Approach’ for planning and implementing water quality improvement works. This specifically delivered a catchment-scale study of how to reduce flooding severity and sedimentation while optimising ecosystem services. Living Water wanted to assess whether an ecosystem services approach would help farmers and stakeholders to see the real value of enhancing native biodiversity (particularly wetlands) on farms. An advisory committee made up of representatives from Northland Regional Council, Whangarei District Council and DairyNZ were involved in designing the trial carried out in the Wairua catchment, Northland, from January 2016 to June 2017.
Who could use an Ecosystem Services approach?
More work is required on the approach before we could recommend this being used as a tool to drive change (further information in the ‘what we learnt’ section below).
What was the approach to the trial?
A catchment-scale assessment and modelling of flood water, water storage, sediment, water quality and habitat for biodiversity was conducted to identify opportunities to enhance ecosystem services, possible land management options to implement in the catchment, and the potential economic and environmental trade-offs that could result from managing the catchment in a variety of ways.
Landcare Research’s economic land-use model (New Zealand Forest and Agriculture Regional Model − NZFARM) was used to estimate the possible catchment-scale impacts for a range of management/mitigation approaches. The model expressly includes the costs of conducting mitigation, which is mostly made up from costs to individual landholders. Living Water held workshops for stakeholders in the catchment, who confirmed that flood mitigation and sedimentation are the key ecosystem service concerns at a catchment scale.
What did Living Water learn from using an Ecosystem Services approach?
The ‘Ecosystem Services’ report identified the most effective farm management practices, financial costs for implementation, and the potential environmental impacts/reductions that could be achieved at a catchment scale in Wairua. Modelling identified that fencing of streams, prioritised soil conservation plantings and detention bunds in all first-order catchments (streams without tributaries) could reduce in-river sediment load by over 50%, reduce in-river Escherichia coli load by 60%, and reduce water spilled in a design flood (estimated flood volume over a specified time) by 25%. The cost is estimated, at $4 million per year (page 64 of the report shows a summary of all the mitigation options including annual maintenance and opportunity costs). This preferred scenario represented a significant improvement to the priority ecosystem services in the catchment, as identified by the stakeholders.
However, the trial found that valuing ecosystem services is complex, especially for wetlands, and that more work needs to be done to be able to use this approach to drive change. We had hoped the trial would clearly show the economic value of wetlands to landowners and to demonstrate that maintaining and enhancing wetlands and water networks on-farm ultimately supports the overall resilience of the farm, especially in the face of climate change and increasing consumer awareness.
What the trial did identify is that solutions to reduce impacts on ecosystem services (in this case reduce sediment) need to be identified, implemented and managed at a catchment scale, and should therefore be carried out by the water network manager (normally the regional or district council).
Started in January 2016 and completed in June 2017