Our places: Project River Recovery
Ngutupare wrybill with Aoraki in the background image: Philip Guilford
Project River RecoveryContext and origins of the Project
Since 1935, water in the Waitaki catchment has been used to generate electricity for the national grid. Collectively, the Waitaki power scheme is the largest hydroelectric generating system in New Zealand, with Lakes Tekapo and Pukaki providing approximately 60% of the country’s hydro storage capacity.
This capacity is potentially under threat as climate changes is leading to glaciers that feed them, shrinking at an alarming rate. The agreement was signed in November 1990, amended in May 2011, and is tied to the term of the power providers’ consents to take and use water, which expire on 30 April 2025. Project River Recovery began operations in late 1991, to undertake ecological management and research programmes.
Key actions
- Maintain indigenous biodiversity and protect and restore terrestrial and river and wetland habitats and their ecological communities by controlling, and where possible, eradicating invasive weeds.
- Continue to test the effectiveness of, and implement, large-scale experimental predator control for population recovery of braided river and wetland fauna.
- Increase awareness of braided rivers and wetlands within a changing environment.
- Continue to gain knowledge of ecosytems in the Upper Waitaki rivers and wetlands through research and monitoring in part by working closely with universities, to enable better management.
- Takes a ‘whole river, whole ecosystem approach’ including the riverbanks, lower terraces and, especially, associated wetlands such as springs, streams, ponds, tarns and backwaters, for the benefit of invertebrates, lizards and fish.
- Established a large-scale predator control operation in the Tasman River to benefit multiple wader bird species. This was the first intensively managed, catchment-scale predator control operation attempted for multiple predator species in a braided river environment.
- Developed a localised, intensive predator control programme centred on an island in the upper Ohau River to test an alternative approach to protecting colonial nesting birds from mammalian predation.
- Examined interactions between feral cats, rabbits and nesting birds near a black-fronted tern nesting site in the upper Ohau River.
- Designed and implemented a survey of terrestrial invertebrate fauna in the Tasman River; this identified a number of undescribed species that are new to science.
- Ongoing management of constructed wetlands, which have been highly successful in attracting a variety of wading birds, waterfowl and other wetland birds and have important botanical values.
- Supported PhD research
- Created multiple educational resources.
Project outcomes to date
- Maintained more than 23,000 hectares of natural braided river habitat by targeted removal of problem weeds before they become widespread, concentrating on protecting high quality habitats.
- Underook weed management of selected sections of modified habitat to restore habitat quality over a further 7000 hectares of braided riverbed.
- Achieved a steady decrease in the coverage and size of Russell lupins on the Tasman River each year.
- Mapped sites with yellow tree lupin and buddleia and continued annual control. This work has achieved a reduction in the presence of these weeds in the basin with a decline in the number and size of plants.
- Investigating the effectiveness of different ways to control Russell lupin.
- Established a comprehensive weed surveillance system to detect and deal with new incursions of weeds.
- Runs weed identification workshops and produced and distributing pocket-sized weed identification booklets to staff and contractors.
How this helps mitigate and adapt to the impacts of climate change
“Healthy and functional ecosystems help reduce climate change vulnerability and disaster risk by:
- Reducing physical exposure to hazards by serving as protective barriers or buffers and so mitigating hazard impacts, including in wetlands, forests and coastal ecosystems; and
- Reducing socioeconomic vulnerability to hazard impacts: sustain human livelihoods and provide essential goods such as food, fibre, medicines and construction materials, which strengthen people’s resilience to disasters.” – Convention on Biological Diversity
Ecosystem services, which are provided free of charge by healthy natural environments supporting high levels of biodiversity, are critical to our existence because they are literally the life-support systems we need to live. This includes the food we eat, clean freshwater, the oxygen we need to breathe, and a stable climate.
Aotearoa’s unique natural history provided us with these free services. But they’re under threat from habitat loss and introduced pest plants and pest animals including herbivores as well as predatory mammals. Climate change is also bringing new and uncertain threats.
Project River Recovery is addressing these threats by using a multi-pronged strategy outlined in Key Actions above, with a special focus on wetlands, nature’s kidneys. Wetlands are also crucial habitats for keystone species, sequester large volumes of carbon in their peaty soils, and reduce the impacts of floods by absorbing water like a sponge and then gradually releasing it.
One easily overlooked but utterly essential action in climate change mitigation and adaptation, is the Project’s research and development strategies to manage and ultimately remove pest weed species. Species such as Russell lupins completely alter the flow regime of braided rivers, constricting normally braided rivers across a wide braidplain into single, fast flowing channels. This destroys native habitat, compromising essential life supporting ecosystem services including flood mitigation at a time when flood frequency and intensity is already increasing due to changing climate.
“Current understanding of how New Zealand’s indigenous ecosystems and species will respond to climate change is very limited, reflecting a long-standing shortfall in research funding for understanding or predicting climate change impacts.” – National Climate Change Risk Assessment for New Zealand
The Project is both supporting and leading research. Much is still not understood about the range and behaviours of introduced pest species in different habitats. They are highly successful generalist species, very capable of adapting to new environments, new food sources, and new challenges (including efforts to eradicate them and a warming climate). This gives them an advantage over native species that evolved to live in specialist niche habitats. Pest species are being tracked and monitored to better understand their behavior and range. The results from this research and experimentation will help the future management of ecosystems both here and elsewhere in Aotearoa.
Our glaciers are melting. Rapidly. And this region will be one of the most affected. As glaciers retreat, some lakes will expand while new lakes and tarns will form. In some parts of the project area, rain is predicted to increase but less snow may fall, increasing the risk of floods and landslides (melting snow releases water more slowly). Other areas are predicted to have less rainfall. These extremes could impact the reliability of hydroelectricity generation at a time when we are divesting from fossil fuels and need to ensure ongoing power supply. The number of frost days will decrease and cold-loving species will try to migrate to higher altitudes.
Having data across these wide range of habitats and ecosystem types is
also immensely useful in tracking when and how species (including pest
species) migrate to new places and higher elevations in response to a
warming climate (this is known as ‘phenological shifting’; find out more on this website). Changes in this area include rising temperatures and rapid retreat of alpine glaciers and subsequent formation and expansion of glacial lakes.
Raising the profile of braided rivers as unique and valuable ecosystems among policy-makers, ecologists, conservation groups, the general public and various stakeholders is changing the way we value these complex ecosystems and their importance in developing climate resiliency.
The extraordinary volume of research and reports that has resulted from this Project has and continues to provide multiple tools and methods to manage pest species and inform ‘best practice’ ways to protect and restore native ecosystems, which are crucial in developing and maintaining resiliency in a rapidly changing climate.
“Climate change has caused shifts in species’ distributions, changes in cyclic and seasonal behaviour, and altered population dynamics. In addition, it has caused further disruptions from the genetic to the ecosystem level in marine, terrestrial and freshwater ecosystems.” – Department of Conservation
