Relationship between ecological integrity and ecosystem services
This research builds on extensive knowledge of individual ecosystem services and quantifies trade-offs between services, in order to better inform management decisions for a suite of services. We focus on carbon sequestration, water yield, biodiversity and erosion control.
What we are aiming to do
We will examine a suite of ecosystem services at both catchment (Manawatu) and property-scale (St James Conservation Area) and quantify the trade-offs between services when management is optimised for each service. Major management actions are land use change (from non-forest to forest) and wild animal pest control.
What we will investigate and how
We are quantifying change in biodiversity as change in “ecological integrity”, rather than species richness. Ecological integrity implies that the range of indigenous species and appropriate ecosystem-scale processes are adequately represented at the study-scale. We are investigating whether ecological integrity is a service in itself or whether it underpins the other ecosystem services. Optimisations at catchment-scale currently assume that the cost of management change to maximise a given service is equal to the revenue foregone through stock reduction. Therefore, only areas which are currently marginal for pastoral agriculture are selected for maximisation of ecosystem services.
Expected outcomes and achievements
Preliminary results suggest that optimising management for gains in ecological integrity is consistent with increasing carbon sequestration and water quality and mitigating erosion risk. However, water yield is decreased when any of the other major services are maximised. Maximising carbon sequestration through the use of exotic species (such as Pinus radiata) will also result in a trade-off for ecological integrity.
This work deliberately focuses on how biodiversity change is affected by management change and what the implications are for other ecosystem services. A larger piece of work (FRST-funded) pulls together nationwide relationships between a suite of ecosystem services and this strand feeds into the national-scale mapping and modelling.