Ireland's state forestry department Coillte is being restricted in its forestry activities in an attempt to prevent the extinction of pearl mussels, a protected species under European law. Ireland is one of the last places in Europe where this bivalve survives and has the largest remaining population. The pearl mussel is Ireland’s longest living species, living for up to 120 years. Recent surveys show that in all rivers where previously healthy populations of the species survived it is now facing extinction.
Born before Irish Independence
In recent years, many young mussels have succumbed to deteriorating water quality caused by river pollution and siltation. For instance, in 2004 phosphorous and nitrate silt leaked into the Owenriff river in Galway. This caused an algae bloom that asphyxiated most of the mussels living downstream. Such events are often related to the amount of artificial fertiliser applied to Sitka spruce trees, a species introduced to Ireland in the 1830s and now grown commercially. Sitkas need aerial fertilisation if they are to grow on infertile Irish bogland. When the trees are harvested, subsequent soil erosion leads to silt and fertiliser entering rivers. The mussels that manage to survive pollution events are generally the larger ones, many over 100 years old. Their age means that, even though a population remains, its ability to reproduce is inhibited.
Pearl mussels need unpolluted rivers
In 1990 the pearl mussel occurred in just 10 to 12 rivers remote Irish rivers. At the time, these flowed through rural areas where forestry and fertilisers were minimal. Since then, rapid economic and population growth intensified development and forestry activities throughout the country. As a consequence, water quality has deteriorated.
A mussel.. reforming the Irish forestry industry
The minister for agriculture, Mary Coughlan, imposed a moratorium on forestry activities in all pearl mussel areas in May 2005, 18 months after the problem was identified by officials in the National Parks and Wildlife Service (NPWS). Coillte can now neither continue fertilising the trees in these areas nor, it is claimed, cut them down in an economically viable way. The Irish forestry industry faces millions in lost revenue, and it is unclear what the future holds for the Irish pearl mussels.
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