In New Zealand, concerns over security of local food production have been encapsulated in the media over the last year with particular reference to the effects of urban expansion and subdivision on the nationally unique Pukekohe food hub. Effects across wider New Zealand, however, have been largely unknown.
To help fill this knowledge gap, a recent project by Manaaki Whenua – Landcare Research, in collaboration with the Ministry for the Environment, Stats NZ and Waikato Regional Council, quantified land fragmentation nationally for the first time. Land fragmentation is the subdivision of land into smaller parcels, such as subdividing agricultural land and building houses. Land fragmentation often occurs due to urban expansion or subdivision on the peri-urban fringe, such as lifestyle-block development.
The aim of the project was to develop a documented methodology, meet MfE and Stats NZ requirements, and create a national indicator of land fragmentation for use in national State of the Environment reporting, starting with Our Land 2021 that was published in April 2021. The study investigated the effects of land fragmentation between 2002 and 2019, using publicly available data, so the analysis can be repeated in future years. Key datasets included the LINZ Primary Parcels and Topo50 data, together with the Land Cover Database and Land Use Capability from Manaaki Whenua.
The study showed that our most highly productive land has been significantly impacted by land fragmentation. In New Zealand, highly productive land is classified using the ‘Land Use Capability’ (LUC) system, as LUC classes 1–3. This land is a finite and scarce resource, occupying less than 15% of New Zealand’s land area. The most versatile land (LUC class 1-2) with only negligible or slight physical limitations for arable and horticultural use is estimated as occurring in less than 5.2% of the country but is often located in areas subject to land fragmentation.
Highly productive land (LUC classes 1–3) was most impacted by fragmentation into parcels with residential dwellings. By 2019 parcels under 40 ha occupied 38%, 28%, and 17% of the baseline area of LUC 1, 2, and 3 land, respectively. A large proportion of this fragmentation occurred on land used for diffuse rural residence and small parcels (0.4 ha to ≤8.0 ha) with a 109% and 59% increase, respectively, between 2002 and 2019. The degree of peri-urban development varied between regions, with the largest area change occurring in Canterbury. By 2019 the Auckland region now has 40%, 44% and 25% of the regions LUC 1, 2, and 3 land, respectively, occupied by diffuse rural residence and small-sized parcels. The Waikato region also experienced significant change, with an additional 5,000 hectares of highly productive land now being used for diffuse rural residence.
The results of this fragmentation analysis were reported in the latest ‘Our Land 2021’ MfE report, and support the need for the proposed National Policy Statement on Highly Productive Land, currently being developed for consideration by Cabinet in late 2021.
Carrick S, Drewry J, Barnes M, Barringer J, Price R, Ausseil, AG, Jones H, Borman, D. 2020. Land fragmentation environmental reporting indicator – technical methods for analysis from 2002 to 2019. Manaaki Whenua-Landcare Research contract report LC3846. 69 p. https://environment.govt.nz/publications/land-fragmentation-environmental-reporting-indicator-technical-methods-for-analysis-from-2002-to-2019/
Curran-Cournane F, Carrick S, Barnes MG, Ausseil A-G, Drewry JJ, Bain IA, Golubiewski N, Jones H, Barringer J, Morell L 2021. Cumulative effects of fragmentation and development on highly productive land in New Zealand. New Zealand Journal of Agricultural Research. https://doi.org/10.1080/00288233.2021.1918185
Ministry for the Environment, Stats NZ 2021. Our Land 2021. New Zealand’s Environmental Reporting Series Publication number: ME 1555. 61 p. https://environment.govt.nz/publications/our-land-2021/