The river corridor is probably the largest area of managed retreat in an urban centre worldwide. How can our experience inform processes of managed retreat elsewhere? The question is central to this project, which has developed a model of ‘retreat’, ‘relocation’ and ‘re-imagining’. Re-imagining asks how can the land be re-used for projects that further lower environmental and social risks.
Biodiversity
There is considerable interest in biodiversity in the river corridor, both in terms of what is there, and also how this is changing since red zoning and the removal of houses. Existing information is however patchy. This project aims to collate what is currently known, and initiatives underway to gain a more comprehensive insight into biodiversity attributes and change.
Historical Data
This information is drawn from work assembled by Chrissie Williams (see interview in Oral Histories) for a report by Regenerate Christchurch (2017).
The first map shows post-earthquake ground surface elevations in and around the river corridor, derived from 2015 LiDAR data, indicating the likely extent – growing over time - of tidal inundation and flooding (see also). This reality will affect the historical pattern of pre-urban vegetation, as summarised in work undertaken by Lucas Associates in the 1990s (ref).
Map 1: Post-earthquake ground surface elevations in and around the river corridor (Orchard 2017).
Map 2: Ecosystems of the lower Avon-Ōtākaro catchment based on "Black Maps" and the Ecosystems Map of Lucas Associates (Lucas Associates 2025).
Taking these two maps together, the third map represents a biodiversity classification of ecotopes in the river corridor based on a hydrosystems approach (Orchard 2017). The Regenerate report (page 11) mentions some flagship species that could be the basis of restoration efforts in these ecotopes: kūaka/godwit in the estuarine; kereru/wood pigeon in the terrestrial; īnanga/whitebait in the aquatic.
Map 3: Biodiversity classification of ecotopes in the river corridor based on a hydrosystems approach (Orchard 2017).
References:
Lucas Associates (2025) Christchurch ecosystem map. Available at: https://www.lucas-associates.co.nz/christchurch-banks-peninsula/ecosystem-map/
Orchard, S. (2017) Integrated Assessment Frameworks for Evaluating Large Scale River Restoration. Report prepared for the Avon Otakaro Network, Christchurch, NZ. ISBN 978-0-473-39796-8 http://bit.ly/Integrated-assessment-frameworks
Regenerate Christchurch (2017): Ōtākaro Avon River Corridor Ecological Restoration Indicative Business Case.
Community Data
There are three key sources of biodiversity data gathered in the wake of the earthquakes, although they focus on vegetation alone. In 2015, the Christchurch Earthquake Recovery Authority (CERA) completed a survey of trees in the red zone. This database locates 30 000 trees, of which 5000 are fruit and nut trees. Motivations for this survey are unclear, but most likely it was undertaken in response to community interest, not least in foraging.
A map locating these trees was published in The Press at the time, at https://www.stuff.co.nz/life-style/food-wine/food-news/67690529/fruit-foraging-in-christchurchs-red-zone. The data on which this map is based is located in the data hub.
A second source is the Ōtākaro Avon Forest Park website: OAFP is a community group interested in nurturing native plants in the river corridor. They have a number of sites of indigenous ecological significance, based on garden plantings augmented by the group over time.
Seven of these are described at https://www.aofp.co.nz/sites-of-ecological-importance. There were originally a number more; most of these have been identified on the map available under ‘current projects’.
There is considerable scope for citizen science projects to augment such sources of data: see. The ongoing source for citizen science data is iNaturalist, which takes a broader approach to observations, beyond a vegetation focus. The iNaturalist map is here.
Current Projects
A map that assembles data from the OAFP website and field observations undertaken by the Living Lab is here. It identifies key indigenous vegetation patches and projects art a landscape scale:
A second project, undertaken by GEOG 309 University of Canterbury students, in conjunction with the Nature Lab, is available here. This project contains an interactive ArcGIS Dashboard for further analysis and collation of biodiversity data.