Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Restoring wetland ecosystem functioning

Map showing losses in Waikato 1840-1995

New Zealand wetlands have declined significantly since European settlement and those that remain are under severe threat from human activities. Our research aims to assist landowners and managers in the protection and restoration of wetlands by providing scientifically based guidelines to underpin management and restoration strategies. The research will benefit New Zealand by helping prevent further loss and degradation of wetlands. Specifically, by 2016, we aim for a 15% increase over 2009 in the extent of wetlands being restored. The long term outcome will be improved biodiversity condition and resilience of wetlands as measured by a wetland index that we have developed and provided to end users (based on the wetland monitoring handbook listed below).

Who is involved?

The project involves researchers from Landcare Research, NIWA, The University of Waikato, the Department of Conservation (DOC), and Waikato-Tainui's Waikato Raupatu River Trust, and is linked to The University of Waikato’s Freshwater Restoration OBI ( Capacity will be enhanced by direct involvement of leading Northern Hemisphere researchers. Key collaborators are the Department of Conservation, regional councils, Waikato-Tainui, the National Wetland Trust, and NZ Landcare Trust, who will provide ongoing guidance and uptake of results through membership of a Steering Advice Group.

What is being investigated?

We are researching the biodiversity and ecosystem consequences of changing water regimes and nutrient fluxes, to quantify and model underlying environmental controls. In addition, we are quantifying wetland nutrient and carbon budgets for intact systems to provide baselines. Predictions and hypotheses are being tested by field manipulations and restoration case studies in heavily impacted wetlands. Results are informing guidelines and thresholds for effective management and restoration.

Some areas of current or recent research:

  • Characterising and understanding biotic patterns in lowland wetlands (vegetation, nutrients, invertebrates) for species-environment models (‘intact’ and modified wetlands throughout New Zealand, e.g., Southland, Otago, Waikato, Canterbury)
  • Field fertilisation experiments: testing the applicability of foliage N:P ratio as an indicator of N or P limitation across a wetland successional gradient (Waikato wetlands), and testing the resilience of wetland vegetation to nutrient enrichment (Ō Tū Wharekai wetlands; DOC Arawai Kākāriki programme).
  • Experiments on rates of litter decomposition across a wetland successional gradient for comparison with Northern Hemisphere wetland decomposition rates. In collaboration with Professor Tim Moore, McGill University, Montreal, Canada.

Field restoration experiments:

  • Restoring vegetation and invertebrates following willow control at Ramsar-listed Whangamarino Wetland, Waikato. In collaboration with DOC Arawai Kākāriki programme.
  • Recreating rare Sporadanthus restiad bog ecosystem at three sites in the Hamilton basin. Projects led by NZ Landcare Trust and The University of Waikato.
  • Best practice restoration techniques have been summarised in Wetland Restoration. A handbook for New Zealand freshwater systems, published 2010, and reprinted in 2012.