Congratulations to Darren Reidy who defended his PhD thesis on July 24, 2018. Darren’s research focused on the question why some aquatic plants become highly invasive outside their natural distribution area. This is an important question as alien aquatic plants are a major threat to biodiversity and a considerable amount of money is spent on their management and control. Being able to recognise potentially invasive species, before they are widely distributed in their new environment, may facilitate management, and reduce management costs.
In his PhD research, Darren mapped the distribution of invasive, alien aquatic plants in county Cork, Ireland. A shocking observation was that more than 50% of water bodies in Co. Cork contain at least one alien, invasive plant species. This number is nearly twice as high as anticipated.
Darren’s PhD study also emphasised the ease with which many aquatic alien plants can spread. In some cases pieces of stem material as short as 1 cm are highly viable. This emphasises the importance of good hygiene for those involved in fishing, boating, diving and other water sports as many aquatic plants can demonstrate impressive clonal growth from small propagules.
A scientifically exciting part of Darren’s thesis, that is however quite sobering from a water management perspective, is the genetic study of the genus Myriophyllum in Ireland. This work which was in close collaboration with Ryan Thum at Montana State University, showed that traditional taxonomic analysis might not be enough to identify invasive alien species in Ireland. In fact, what appeared as Myriophyllum aquaticum comprised several further species, some of which are of major concern as invasive aliens.
Darren’s work emphasises the importance of both early discovery, and correct identification of invasive aquatic plants, as once established, these species can spread rapidly from small propagules, and are notoriously difficult to eradicate.