Monitoring temporal changes in the early phase of an invasion: Undaria pinnatifida (Harvey) Suringar using the abundance and distribution range method

摘要

The status of the Asian kelp Undaria pinnatifida , was determined using the abundance and distribution range method during a rapid assessment survey. This kelp was first found on the northeast coast of Ireland at Carrickfergus Marina in Belfast Lough, Northern Ireland in 2012. It was not known in Ireland in 2006. U. pinnatifida was one of a set of target species searched for during 2012, and initially it occurred at low levels. By 2013 its population had expanded within this marina. In 2014, some tens of individuals were found for the first time over a hundred kilometres to the south in the Republic of Ireland at Carlingford Lough. Both senescent and young plants were found at these sites. In 2015, the kelp appeared at Glenarm Marina 40 km to the north of Carrickfergus; and in the following year, the population had increased marginally. The kelp was not found at a marina on the south side of Belfast Lough, most probably due to fluctuations of salinity. This account discusses the value of the ADR method for evaluating the recent arrival of this large and easily recognised species .