Biodiversity study concludes at Wiroa

Plant and Food Research have concluded research at Craigmore’s Wiroa kiwifruit orchard in Kerikeri as part of a four-year study to better understand the impact of land use change.

The study commenced in January 2021, shortly after development work began to convert the 137-hectare former dairy farm near Kerikeri to an orchard. The aim of the research was to better
understand how the change from pasture to kiwifruit, along with the addition of indigenous plants close to the kiwifruit vines, would affect biodiversity and ecosystem services and functions.

This was a unique opportunity for Plant and Food Research to engage in a study of this kind at the start of a development project. It was also the chance for multi-disciplinary researchers to
undertake coordinated projects on the same site.

The development plan for the site saw nearly 17 hectares including slopes, gullies and banks close to waterways, planted with 43,000 new native plants (27 species) and four forest types including a mix of native species such as kahikatea, kauri and tōtara.

At the outset of the research, 13 monitoring sites were set up across the orchard to enable assessment of physical soil health and water regulation; biological soil health; the contribution of invertebrates to decomposition; pollinators; plant and invertebrate diversity; vertebrate diversity and to confirm the presence of Kiwi.

The data collected is considered baseline data, because it may be several years before the impact of land-use change can be fully measured. It is pleasing however to see early trends, with the change from pasture to kiwifruit resulting in improvements in soil structure and increased diversity in the soil biome.

The study also detected increases in invertebrate and plant diversity in kiwifruit blocks next to areas of native plantings, and increases in diversity of pollinator species and visitors to kiwifruit flowers next to areas of indigenous plants. In addition, a unique indigenous, and currently unnamed, species of slater (also known as woodlice) was discovered, along with
confirmation that native bats and Kiwi are moving into the orchard to forage for food. It is exciting to note that one of the Kiwi filmed was a juvenile, meaning we have a breeding population, which is testament to the predator trapping programme.

Findings from the research will now be compiled with the aim to have papers published in relevant journals over the coming 12 months. Once fully documented, it is hoped that the baseline data presented in these papers will be used as the basis for ongoing research.