“Deer, Chamois Main Cause Of High-Country Erosion”

Press, Volume XCIX, Issue 29270, 30 July 1960, Page 14

“Deer, Chamois Main Cause Of High-Country Erosion”

(New Zealand Press Association)

DUNEDIN, July 29. Fires and sheep were no longer the most important destructive agents in causing erosion but deer, chamois, and opossums had become the main danger, Mr J. T. Holloway, head of the forest and range experiment station of the New Zealand Forest Service, told a meeting of the Otago University Biological Society. Showing how erosion in the high country had increased in the last 50 years, Mr Holloway said it began with the burning of forests and tussock grasslands to obtain grazing. At first grazing was rich with a good cover of grass, but with heavy grazing and trampling, the cover became thinner until heavy rain opened up gullies on the hillsides—often several in one night. In most cases the damage was irreparable, he said.

Mr Holloway stressed that the dangerous areas were the “tops’’ and not the lower slopes. Even if the latter were in excellent condition there was always an erosion hazard if the “tops" were in poor condition, he said. No method of control had yet been found for the wild animals which were the main cause, said Mr Holloway. Erosion did not call for a wholesale removal of sheep from the mountains, but higher and more vulnerable areas should not be grazed by either sheep or wild animals. Little was known about the habits of deer, opossums, and other introduced animals but forest service workers were making efforts to gain this information—often in extremely remote areas under very difficult conditions. Survey in Hokitika In a recent survey of the Hokitika Catchment, 96 inches of ram fell in 11 days. Only a complete cover of vegetation could hope to control that amount of rain adequately, said Mr Holloway. Expensive flood control works were necessary on the lower reaches of some rivers but were only temporary so long as the source of the trouble —the upper catchment areas—was ignored. No cover on the mountains meant “flash" floods, masses of gravel brought down on to the plains, soil swept out to sea, continuous damage to communications and loss of valuable lowland farming areas. Mr Holloway said that the universities could help by undertaking some of the necessary research and in educating the public towards a full understanding of the problem and some of its implications.