Friday, 23 April 2021 15:30

Spatial distribution of grape varieties around New Zealand

Written by  Jim Herdman
Dr Seth Laurenson Dr Seth Laurenson

Over the past four months, New Zealand Winegrowers has been working with the Hyperfarm team at AgResearch, led by Dr Seth Laurenson, to map the growing locations for all commercial wine grape varieties across New Zealand.

This information will ultimately be useful for members assessing the predicted impacts on wine regions and the suitability of varieties as the climate changes. The Hyperfarm team has employed a geographic information system (GIS), data interrogation methods, satellite, and aerial imaging to identify and validate vine growing locations using anonymised vineyard physical address information, stored in the New Zealand Winegrowers (NZW) database, that creates the coordinates held in the Biosecurity Vineyard Register.

To begin the mapping process, AgResearch’s Geospatial Analyst Peter Pletnyakov transformed addresses into coordinates using reverse geocoding and measured the address proximity to the nearest vineyard record in the landcover database. Where the distance between address and vineyard was large, aerial imagery was used to confirm a vineyard location. During the verification process, it was discovered that 678 vineyards were missing from the landcover database and were generally poorly classified. In total, the Hyperfarm team validated 1,852 locations across the country. They are now able to produce accurate maps of vine distribution for different wine grape varieties.

Future steps will include assessing how predicted patterns in climate conditions will influence growing regions over the next 50 years. This information will help inform decisions such as changes in suitable vine varieties, vineyard expansion or shifts into new growing regions. The accurate vine location maps provide a powerful validation set for the Hyperfarm team to test and calibrate their land use suitability model for wine grapes in New Zealand. “In developing the land use suitability model we collated data from around the world on such things as altitude, slope, growing degree days, winter chill hours, soil pH, bedrock depth, water holding capacity and irrigation, amongst other bioclimatic variables. This information helps us understand the ideal growing conditions for different grape varieties,” says Seth. “We are now able to validate these global models to the New Zealand conditions and create maps of where we think grape varieties can grow around the country, including those grape varieties we do not currently grow.”

Hyperfarm has a computer-based visualisation tool that allows users to design and visualise future landscapes and explore new land-based opportunities. A suite of scientific models that are geospatially explicit to the location underpins the process and helps the user understand an array of environmental, social, and financial factors associated with a particular change to the climate and region. Understanding and coping with the effects of long-term climate change is one of NZW’s primary concerns, so this work should help growers assess any future threats and identify new opportunities.

The NZW biosecurity team is also pleased with the Biosecurity Vineyard Register’s improved accuracy as a result of the collaboration, and asks members to check the vineyard physical address information held on the database. This improved accuracy will help notify potentially impacted members if there is a biosecurity incursion in their geographical area.

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