Moth Conservation
Moths in Decline - Part 2
29/01/2024
Loss and degradation of semi-natural habitats and impacts on our moths
Species rich grasslands are an important source of nectar for adult moths and provide a wide range of food-plants for their larvae. Decades of loss and fragmentation has had significant impacts on our nature.
Decades of agricultural intensification, use of chemicals, clearance of woodlands and scrub habitats and loss of species rich grasslands, which supported the range of plants, which in turn our moths rely on, has been a major factor in the loss of insects.
Northern Ireland is one of the least wooded regions of Europe. Of the ancient woodland, that once covered most of the land only 0.04% remains. Peatlands cover approximately 12% of Northern Ireland, but more than 80% have been damaged by decades of drainage, afforestation, overgrazing, vegetation burning and peat removal as fuel. More than 30% of Northern Ireland’s species rich dry grasslands were lost in only nine years between 1998 and 2007.
The result has been a near monoculture of rye grass across many parts of the region, with heavily pruned hedgerows, all to increase agricultural productivity. These can support a very limited range of insect life. The patches of “untidiness” of greatest value to nature, have become less numerous, smaller and more fragmented, in drive for efficiency and maximising production.
To maintain this level production requires significant inputs of chemicals, in form of pesticides fertilisers, with further direct and indirect impacts on our nature. There is evidence that moth species with larval foodplants more tolerant of high nutrients are those fairing better.
Historic and current development in formally wild areas creates death by a thousand cuts. The loss of the Belted Beauty from it’s last known home in Northern Ireland, close to Ballycastle coincided with the development of Ballycastle Golf Club in the 1890’s when the Bonamargy Dunes, which were formally a rabbit warren, became the new course. As the female is flightless there is no hope of natural re-colonisation.
As well as the direct impacts of habitat loss from developments the increased use of artificial lights could have significant impacts on our moths. Studies have demonstrated that such lighting not only interferes with migration and movements, but also impacted pheromone production, reduces larval development and inhibit feeding behaviour. A study in southern England has shown that street lighting reduced moth caterpillar abundance by 33% in grass verges and 47% in hedgerows, when compared to similar unlit habitats. The suburbanisation of the countryside, by what became known as “bungalow blight” has played it’s part, though planning policies are now in place to limit further expansion.
Northern Ireland is one of the least wooded regions of Europe. Of the ancient woodland, that once covered most of the land only 0.04% remains. Peatlands cover approximately 12% of Northern Ireland, but more than 80% have been damaged by decades of drainage, afforestation, overgrazing, vegetation burning and peat removal as fuel. More than 30% of Northern Ireland’s species rich dry grasslands were lost in only nine years between 1998 and 2007.
The result has been a near monoculture of rye grass across many parts of the region, with heavily pruned hedgerows, all to increase agricultural productivity. These can support a very limited range of insect life. The patches of “untidiness” of greatest value to nature, have become less numerous, smaller and more fragmented, in drive for efficiency and maximising production.
To maintain this level production requires significant inputs of chemicals, in form of pesticides fertilisers, with further direct and indirect impacts on our nature. There is evidence that moth species with larval foodplants more tolerant of high nutrients are those fairing better.
Recent studies have shown that the most dramatic declines in moth numbers have been in woodland species, such as the Copper Underwing. The reasons are not fully understood, but perhaps woodland species have been the least impacted by declines up to now.
Historic and current development in formally wild areas creates death by a thousand cuts. The loss of the Belted Beauty from it’s last known home in Northern Ireland, close to Ballycastle coincided with the development of Ballycastle Golf Club in the 1890’s when the Bonamargy Dunes, which were formally a rabbit warren, became the new course. As the female is flightless there is no hope of natural re-colonisation.
Ballycastle golf course with Fair Head in the background. This may have been the last site for the Belted Beauty in Northern Ireland.
As well as the direct impacts of habitat loss from developments the increased use of artificial lights could have significant impacts on our moths. Studies have demonstrated that such lighting not only interferes with migration and movements, but also impacted pheromone production, reduces larval development and inhibit feeding behaviour. A study in southern England has shown that street lighting reduced moth caterpillar abundance by 33% in grass verges and 47% in hedgerows, when compared to similar unlit habitats. The suburbanisation of the countryside, by what became known as “bungalow blight” has played it’s part, though planning policies are now in place to limit further expansion.