Monitoring at Hikaroroa

Monitoring for better conservation decisions

Monitoring is a core part of the Hikaroroa / Mt. Watkin Conservation Project because pest control alone doesn't tell us whether management is having the intended result. The number of traps set or animals killed tells us what work has been undertaken, but the more important questions are:

• has that work actually reduced pest populations, and
• have those reductions been significant enough to allow the ecosystem to thrive?

Our monitoring programme is therefore built around an adaptive management approach. We collect information to evaluate the ecological responses, and use what we learn to refine how intensively and what kinds of management activities to undertake. Over time, the aim is to develop an understanding of site-specific relationships between pest abundances and biodiversity recovery indicators — essentially determining how low different pest populations need to be for measurable ecological benefits to occur. This approach reflects the framework established in the DCC's Hikaroroa / Mt. Watkin Vertebrate Pest Management Strategy and subsequent project monitoring reports.

Practically this works through two interconnected types of monitoring, which together allow management objectives to progressively move beyond measures of work conducted, such as “number of pests killed,” toward ecologically meaningful targets.

1.  PEST MONITORING:  Management-response monitoring — are our interventions working?
Pest monitoring measures the change in relative abundance and rough distribution of possums, rodents, mustelids, feral cats, deer, goats and pigs independently of the control programmes themselves. This helps us determine whether changes in trap catches genuinely reflect changes in pest populations rather than changes in trap performance, animal behaviour, or control method efficiency. Independent monitoring also provides an important measure of accountability for landowners, funders, project partners and the wider community.

The Hikaroroa pest monitoring programme uses repeatable field methods to measure changes in pest abundance independently of the control network. Monitoring spans both the Hikaroroa / Mt. Watkin Scenic Reserve and significant native habitat on surrounding private land, helping us understand pest populations and reinvasion pressure at a landscape scale.

The established predator monitoring network includes 19 tracking-tunnel and wax-tag transects and 20 camera monitoring sites distributed across different habitats and elevations. We also use the camera network to undertake standardised ungulate monitoring for deer, goats and pigs.

Learn more about our specific pest monitoring methods.

2.  BIODIVERSITY MONITORING: Ecological-response monitoring — are we achieving ecological outcomes?
Biodiversity monitoring asks what happens after pest pressure is reduced. Are native birds becoming more abundant? Are larger-bodied terrestrial invertebrates recovering? Are palatable native trees successfully recruiting into the forest? These changes can take years to fully mature, so maintaining consistent long-term datasets is an important part of understanding whether our management activities are working.

The Hikaroroa biodiversity monitoring programme currently focuses on three broad ecological indicators representing taxonomic groups and ecological values that are particularly important or vulnerable within the project area: native forest birds, terrestrial invertebrates, and native forest regeneration.

These indicators were selected because they represent important ecological values of Hikaroroa while also being measurable using established, repeatable and relatively affordable monitoring methods. Together they allow us to examine ecological responses to both introduced predators and browsing mammals.

Our current programme deliberately focuses on general ecosystem indicators rather than attempting intensive population monitoring of every threatened species present. As the skills of our community monitoring team develop, partnerships grow and funding allows, we hope to increasingly complement these general indicators with targeted monitoring of threatened species such as kārearea, native lizards and threatened Lepidoptera.

Learn more about our specific biodiversity monitoring methods.