Media Release

1 December 2015

- for immediate release

Spotlight on state of lake

Lincoln University Professor Ken Hughey says it will take decades, if not generations, to stop the degradation at Te Waihora/Lake Ellesmere, but the right processes must be implemented now for restoration to occur.

“A number of these processes are already in place, which we should be very proud of,” he said at the recent fifth biennial Living Lake symposium held at Lincoln University.

The event, run by the Waihora Ellesmere Trust (WET), included presentations from a range of experts on such topics as land use, water quality, vegetation and recreation at the lake and catchment. The aim was to provide an update on how these areas had fared since the last symposium in 2013.

The format of the event differed slightly from previous years in that the symposium began with a field trip to the lake, followed by a day of presentations where the audience was given the opportunity to direct questions to panels of experts.

A key factor highlighted this year was that increased economic activity in the Selwyn district due to a rise in population had placed greater pressures on the lake, with more dairying and contract grazing taking place.

Kirsty Johnston, of Environment Canterbury (ECan), said Farm Environment Plans (FEPs) were helping to reduce these pressures by encouraging sustainable farming practices.

However, she said more data was needed to assess the situation further and that future FEP audit results would be helpful.

She also recommended that geographic information systems be used more regularly for reporting on the state of the lake.

Another key issue raised at the symposium related to a new regime involving planned lake openings, which create periodic connections with the sea.

This allows many fish species to pass in and out of Te Waihora/Lake Ellesmere, lowering the lake level and providing nesting and feeding opportunities for birds.

However, when these openings persist over summer, they can have negative impacts on some native plant communities and birdlife.

ECan Senior Engineering Advisor Leigh Griffiths said the lake had been opened to the sea 10 times between January 2013 and June this year.

Three long opening periods took place in 2013, with the lake open for 68 days, 47 days and 60 days respectively, during which times the lake level dropped.

ECan Ecology Scientist Kimberley Robinson, who spoke about the water quality of Te Waihora/Lake Ellesmere, said these openings had led to an increase in salinity, resulting in visibly clearer water. However, she pointed out that a more saline environment could be detrimental to certain species in the lake bed.

She said Te Waihora/Lake Ellesmere remained in a hypertrophic state.

“This indicates nutrient saturation, elevated algal biomass and decreased water clarity. Many of the lake’s tributary streams need to be improved, as a high proportion are graded poor.”

She welcomed the recent instalment of permanent monitoring stations in the lake, which would provide real-time information on water quality.

In her presentation on the state of vegetation around the lake, ECan Senior Biodiversity Officer Jodi Rees said high salinity levels resulting from the prolonged lake openings in 2013 had impacted badly on some of the lake margin vegetation.

She also said inappropriate use of off-road vehicles, as well as ongoing stock grazing at Greenpark Sands, had destroyed a substantial amount of vegetation.

Her recommendations included prioritising extra resources to control weeds and protecting vegetation by reducing vehicle and stock access to the area.

Professor Hughey echoed the latter sentiment when discussing the state of recreation at Te Waihora/Lake Ellesmere.

“We need to stop vehicles from wreaking havoc on a habitat of international significance,” he said.

Professor Hughey’s presentation indicated that there was very little new information about recreational use of the lake.

“This is lamentable, as we should be able to monitor how recreation is changing. To measure is to manage.”

He recommended establishing an expert panel of recreational users to monitor activity over the next two years.

“It’s costly to survey recreation, so setting up a panel would be a good solution.”

Ends

WET has published a new report, Te Waihora/Lake Ellesmere State of the Lake 2015, which summarises the findings presented at the Living Lake Symposium and can be downloaded at http://www.wet.org.nz/projects/2015-state-of-the-lake/ along with other relevant information. The presentations from the speakers at the symposium can also be downloaded.

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