New Zealand's alpine ecosystems threatened by rapid weed spread

Wellington, June 23 (IANS) New Zealand's alpine springs, once renowned for their pristine waters and rich biodiversity, are now under serious threat from rapidly spreading lowland aquatic weeds.

Researchers from the University of Canterbury (UC) have documented the rapid invasion of species such as monkey musk and watercress into high-country waterways, including remote springs in the upper Waimakariri region in the South Island, according to a UC release on Monday.

The research team used the UC data dating back to 2004 to reveal that invasive weeds have rapidly spread even to remote areas and have established themselves in previously untouched habitats, causing a recent decline in invertebrate diversity, the release said.

While nutrient enrichment has been ruled out, researchers are investigating factors such as rising temperatures, grazing by introduced animals, and the spread of seeds by humans and wildlife, it said, Xinhua news agency reported.

These findings echo broader concerns that climate change and increased human activity are accelerating the movement of invasive plants into higher altitudes, putting unique alpine ecosystems at risk, researchers said.

"While the springs are biodiversity hotspots, a refuge for native species with cold, clear water and rich invertebrate life, but that's rapidly changing," said Helen Warburton from the UC's School of Biological Sciences.

While weed control efforts are underway, scientists warn that urgent, coordinated action is needed as climate change and tourism threaten to further endanger these alpine biodiversity refuges.

The New Zealand government is also stepping up efforts to control the spread of invasive wilding pines, with a 20 per cent increase in funding that brings total investment to 12 million NZ dollars for the coming year.

Agriculture and Forestry Minister Todd McClay said recently that wilding pines are a major threat to the country's rural economy and landscapes.

"Wilding pines cost the rural community significantly and are often the bane of farmers' lives. We have an obligation to work with them to control their spread, and reduce on-farm burden," McClay said.

Over 2 million hectares of land across New Zealand are affected, and infestations are expanding at around five per cent annually. If unchecked, the economic impact is estimated to reach 3.6 billion NZ dollars over the next 50 years, according to government statistics.

Biosecurity Minister Andrew Hoggard highlighted the environmental risks, noting that wilding pines harm native ecosystems, drain water resources, and increase the risk of wildfires.

--IANS

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