Biodiversity project effectiveness programme
A significant component of our biodiversity programme is on-the-ground projects in partnership with willing landowners, agencies, non-government organisations, rūnanga and others on private (and sometimes public) land.
While we provide regular reporting of project outputs and expenditures, reporting on whether this work has been effective or if the outcomes have been achieved has been limited.
To address this gap, the biodiversity project effectiveness programme provides an opportunity to monitor and assess biodiversity projects that have previously been completed.
This work is in essence an internal check on the biodiversity work programme, ensuring that we continue to target biodiversity projects in a way that is the most effective use of resources and where the outcomes are likely to be achieved.
Projects are selected from work completed four years prior, which allows for the time lag between actions taken and the benefits being realised.
Effectiveness and progress summary
Over seven years of the programme, the results have indicated that the effectiveness of biodiversity interventions in the medium term, and specifically in the long term, continues to be highly dependent on the site being actively managed after the biodiversity intervention has taken place
Regular ongoing maintenance by either the landowner, community groups or contractors is key for the biodiversity gains to be maintained and increased.
Project effectiveness
In 2024/25, 18 project sites were measured by biodiversity staff for intermediate-term effectiveness, by assessing standardised outcomes for different project actions (for example, fencing, weed control, planting, animal pest control).
The likelihood of longer-term effectiveness was measured by:
- assessing factors such as physical and ecological context and connectivity
- ongoing risks and threats
- site management
- legal protection.
Average score for intermediate effectiveness score (out of 5): a score of 5 means that the outcome is met, there is a tangible positive outcome and there are no risks to achieving the outcome.
Average score for long-term effectiveness score (out of 3): a score of 3 means that there is a high likelihood of long-term effectiveness and no tangible negative impacts.
Effectiveness in action: Two project sites
The following two examples are part of a broader assessment of 18 project sites, where biodiversity staff evaluated intermediate-term effectiveness by measuring standardised outcomes across various project actions such as fencing, weed control, planting, and animal pest control.
Ribbonwood Station fencing
Overall intermediate-term effectiveness score: 2.41
Likelihood of longer-term effectiveness score: 1.8
This project aimed to safeguard sections of the Willowburn Stream and nearby wetlands from stock damage and invasive willow species.
While the fencing was completed during the 2019/20 year, it was initially installed in the wrong location.
This delay allowed sheep and cattle to graze extensively in the intended protection zone, resulting in pugging and potential sedimentation issues in the creek.
The fencing issues were later fixed, and stock are now kept out of the wetland area between the two creek channels. While early setbacks affected the project's short-term success, the long-term outlook is more promising thanks to these improvements.
North branch of stream prior to fencing
Tunnel Road Reserve saltmarsh restoration
Overall intermediate-term effectiveness score: 4.4
Likelihood of longer-term effectiveness score: 3.0
This restoration project focused on rehabilitating fire-damaged areas within the Tunnel Road Reserve in Christchurch by re-establishing native saltmarsh ecosystems. The approach involved scraping the surface of the affected grassland to remove invasive grasses and lower the ground level, allowing seawater to naturally re-enter the area. This created ideal conditions for the regeneration of native saltmarsh and salt meadow species.
To support the restoration, native saltmarsh ribbonwood was planted along the site’s bunded edges by council staff and volunteers, enhancing biodiversity and habitat structure.
Monitoring has shown promising results, with the area successfully recolonised by saltmarsh species. Early signs of ecological recovery include the presence of crabs, amphipods, and nemertine worms, which are expected to increase over time. Birdlife has also returned, with oystercatchers, white-faced herons, and pūkeko observed on site.
The scraping method proved to be both effective and cost-efficient, achieving the project’s restoration goals. The long-term success of the initiative is supported by the site's status as a city council reserve, ensuring ongoing protection and active monitoring.