INVASIVE PLANT species are taking over unfinished housing estates in Kerry and threatening serious damage to building by growing through substrata such as concrete and tarmac, a report into biodiversity in urban areas in the county has warned.
The main town of the Iveragh peninsula, Cahersiveen, surrounded by areas of special conservation interest, is worst affected, according to the study by Atkins consultants, commissioned by Kerry County Council.
The invasion of exotic alien species was “widespread” in Cahersiveen, where 15m (49ft) long banks of the Japanese knotweed, which grows rampantly, had been spotted within the town, the study found.
Cahersiveen has a number of unfinished housing estates, the report noted. Himalayan knotweed, giant rhubarb and rhododendron were also problematic in Cahersiveen, the research into four urban areas including Tralee found.
Japanese knotweed, which is one of the world’s worst and most prolific invaders, spreading from tiny pieces to form leafy canopies 3m high, choking out other plant life, was also found on river banks in Tralee town centre.
The “highly invasive” species found in Kerry’s biggest town could damage flood defences as well as houses and buildings, and destabilise the river banks, according to the study.
“Of four towns studied, Cahersiveen supported the greatest cover, spread and variety of invasive exotic shrub species,” it said.
Japanese knotweed was “consistently found” in consolidated clumps and in scattered patches on roadsides, areas of unfinished housing developments and isolated spoil and rubble heaps throughout Cahersiveen, the report said.
The unfinished nature of the housing estates on the western side of the town provided opportunities for the establishment and spread of invasive species “through the various open and unstable parent materials on site”, it said.
The report recommended a further study be carried out, followed by a control and eradication programme.
The north Kerry coastal towns of Ballybunion and Tarbert were not as badly affected, it found.