Lake assessment tool earns high honour for NIWA scientist

John Clayton, a principal scientist in the fields of aquatic biodiversity and biosecurity based at NIWA's Hamilton office, has won a 2011 Kudos award for his leading role in the development of LakeSPI  (Lake Submerged Plant Indicators). LakeSPI is a  tool widely used to assess and rate the ecological condition of New Zealand lakes.

The Kudos Awards are coordinated each year by the Hamilton Science Awards Trust. They offer cash prizes to individuals judged by a panel of specialists to be advancing science in the Waikato Region in an exceptional way. There are four awards categories: agricultural science, environmental science, medical science, and science education. John's achievement was in the environmental science category.

Development of LakeSPI is the culmination of over 30 years' work by John to help improve the health of New Zealand freshwater environments through better assessment, management, and control of aquatic weeds. The eradication of alien weeds is a particular focus. John was a key advisor to organisers of the recent World Rowing Championships at Lake Karapiro, on weed problems potentially affecting the course.

"My aim is to supply robust and pragmatic tools and solutions for water body managers charged with managing aquatic vegetation resources and issues," he says.

A key environmental indicator

LakeSPI is based on the principle that the type, quantity, condition, and depth of submerged plants are effective indicators of lake health. John completed over 1000 SCUBA dives in New Zealand freshwaters during development of the new, rapid-survey method.

"Any New Zealand lake can be characterised by the composition of native and invasive plants, and the depths at which they grow," he says. "The plants are easy to observe, stationary, indicate long-term changes in environmental condition, and allow us to focus on lake margins – the areas of greatest and most varied recreational and commercial use."

Once suitable indicator plants have been identified in a lake, they are observed at regular intervals. LakeSPI then applies a simple "scoring" system, comprising three indices: native plant condition index, invasive plant impact index, and LakeSPI index. The latter is synthesis of the first two and is a comparative measure of the lake's overall ecological condition. A high native plant index is favourable, while a high invasive plant index is undesirable. The higher the LakeSPI index, the better the overall health of the lake. Ongoing measurements indicate trends and rates of change.

LakeSPI findings are presented in a way that enables water body managers to quickly compare the quality of lakes under their care, and design catchment and lake management strategies accordingly. The tool has already risen to prominence as a key environmental indicator for New Zealand's lakes and is widely used in regional environmental monitoring. A recent Ministry for the Environment report recommended it as one of a small number of indicators of water quality for national State of the Environment (SOE) reporting.

John says he is thrilled to have been honoured for his work in an area that is so important to many New Zealanders, and has such a broad practical application.

"It is both a delight and an honour to receive this excellent Kudos award. I am also grateful to be supported and inspired by a team that has contributed widely to the management of New Zealand's freshwater biodiversity and biosecurity," he says.

"LakeSPI was certainly a milestone in the understanding of our lakes, and my colleague Tracey Edwards played a key role in helping me develop LakeSPI and work through the various prototypes before we were happy to go live. Once LakeSPI had accumulated a considerable database of information, Mary de Winton completed a comprehensive analysis that was critical to validating assumptions in the model.

"Successful research often takes years of investment, and a stable funding base is important to achieve results like this. With escalating pressure on New Zealand's freshwater resources, the challenge now is to find ways to adequately resource future research to help protect our unique indigenous values and focus on better tools to help curb the spread of invasive species." 


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John Clayton in Lake Matheson