Invasive Weeds Threaten Ireland's Waterways as Warming Temperatures Set Stage for More Growth

Rising global temperatures threaten to cause a resurgence of invasive water weeds that will threaten biodiversity and hamper tourism in Europe, according to a new study.

Queen's University Belfast researchers report that a number of invasive weeds which have previously been killed off due to lower winter temperatures will thrive as global temperature increases.

Writing in the journal Diversity and Distributions, the researchers predict that over the next 70 years these invasive water weeds will become more widespread, particularly the water fern, parrot's feather, leafy elodea and the water primrose - all of which are already considered problem species in Europe.

Those four waterweed species in particular could expand their range by up to 38 percent, the researchers report. They said that the annul cost of managing invasive plants and animals in the UK is estimated to be £1.8 billion ($2.98 billion)

The study was led by Ruth Kelly, who looked at the global distribution of 15 invasive plant species across a 69 year period.

"Traditionally upland areas have been protected by low winter temperatures which kill off these invading weeds. Now these are likely to become increasingly vulnerable to colonization," Kelly said. "On the island of Ireland currently about 6 percent of the island is unsuitable for these invasive species but we think this will drop to less than 1 percent by 2080."

Kelly said the researcher and more like it will prove valuable to the Northern Ireland Environment Agency (NIEA) and other agencies tasked with ensuring the UK's waterways remain viable economic and recreational resources.

"It's not all bad news, however, as our most common invasive waterweed, the Canadian pondweed, is likely to become less vigorous perhaps allowing space for restoration of waterways and native plant communities," Kelly added.

Michael Meharg, from the NIEA, which funded the study, said: "Invasive waterweeds can be a major problem in lakes and rivers throughout Britain and Ireland. Such plants are fast growing and often form dense mats of vegetation which may block waterways and cause problems for boating and fishing, and, therefore, to the leisure and tourism industries. Dr. Kelly's research is crucial in planning for the future as we know invasive waterweeds will also out-compete native aquatic plants species and alter habitats for insects and fish."