30/07/2021 at 2:55 pm #70296Allan BurgessKeymaster
Report shows waterways in the Canterbury high country are heading the same way as the plains
Source: Fish and Game NZ
North Canterbury Fish & Game are concerned by the findings of a major Environment Canterbury (ECan) report showing land-use intensification in the Canterbury high country.
ECan scientists found 6,847 hectares in the Waimakariri, Rakaia, Hakatere/Ashburton, and Rangitata river catchments had been developed in the 1990-2019 period.
The report links this change to deteriorating water quality in high country lakes and spring-fed streams.
Rasmus Gabrielsson, Chief Executive of North Canterbury Fish & Game, says, “The report puts on paper what the public has witnessed in the high country for some time. Anyone who has spent time in the high country has seen the intensification, shifting from a landscape dominated by the browns and greys of tussock and shrubland to the cultivated green pasture and fodder crops more associated with the Canterbury Plains.”
The ECan report states that “On the lowland plains of Canterbury there has been a progressive loss of aquatic habitat and values to facilitate agricultural efficiency. Land-use intensification in the high country, if un-regulated, is likely to result in similar outcomes” (page 21).
This reinforces a report released by ECan last year, which showed that iconic high-country lakes in the high country, such as Pearson and Grasmere, show declining water quality trends. These lakes are sliding down the trophic index level from being near-pristine to a more turbid state.
The ECan report states that lakes were particularly vulnerable to land use intensification as they can be ‘accumulators’ of inputs of contaminants such as nutrients and sediment from their catchments.
In conducting the study, scientists looked for signs of intensification, including removing woody vegetation, removing native tussock grasses, newly bare (cultivated or sprayed) paddocks, newly sown paddocks, and the installation of irrigation systems.
Areas targeted for agricultural development tended to be flat or gently sloping landforms such as the beds and margins of braided rivers, terraces, outwash plains, alluvial fans and moraines.
Gabrielsson says, “We must act now and do more to save our iconic but sensitive lakes, wetlands and waterways high country environment from further degradation”.
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