Awareness urged over weed spread

An Otago scientist is calling for a campaign to raise public awareness of the potential for trampers and recreational vehicle users to spread invasive plant species in New Zealand's alpine areas.

University of Otago department of botany Prof Kath Dickinson said the growing number of hikers and tourists in alpine areas and the opening up of more alpine places for recreational vehicle users was increasing the likelihood of introduced species getting into the environments.

Prof Dickson's call follows the warning by a team of international scientists who found alpine plants around the world were at risk of extinction due to climate change, skiing and mountain tourism spreading weeds to higher altitudes.

A New Zealand researcher on the team, Lincoln University's Prof Philip Hulme of the Bio-Protection Research Centre, said the research conducted in Italy and published in ''Nature Climate Change'' showed that as temperatures rise, weeds spread up mountainsides to higher altitudes twice as fast as native plants.

''I suspect the situation is possibly far more dire in New Zealand. Our mountain regions are coming under increasing pressure from tourism, skiing developments and other infrastructure such as roads,'' Prof Hulme said.

Systematic, long term data on how flora was changing in New Zealand alpine region was no longer being collected but it was essential ''if we want to keep our glorious landscapes free of weeds such as gorse, broom and wilding pines.''

University of Otago Emeritus Professor of botany Sir Alan Mark agreed.

He said ''only long term detailed records could provide answers and these are very few in New Zealand, though not infrequent overseas.''

Department of Conservation technical adviser Keith Briden said climate change may result in more storm events which would create more site disturbance allowing weeds and wilding conifers to colonise those areas.

Wind events would also distribute more conifer seeds on to disturbed areas which would result in more wilding pines above the bush line, he said.

In the past year Doc has spent $5million removing more than a million hectares of ''light infestations'' of wilding conifers, and large areas of alpine and sub alpine have also been cleared, Mr Briden said.

Prof Dickinson said the wilding pine issue continued to be a huge concern, in particular to high country farmers, but there was now also widespread concern about a group of invasive grasses known as the hawkweed group.

Skifield development going progressively higher and higher up mountain ranges, chasing the snow, and the increasing movements of tourists into alpine regions on helicopters and other transportation also increased the risk of spreading non-native grass species, she said.

Prof Dickinson believed an public awareness campaign similar to the one preventing the spread of didymo in lakes and rivers would slow the spread of invasive plants species in to our alpine areas.


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