Moth Conservation
Moths in Decline - Part 3
29/01/2024
Moths in a changing climate
Some moths adapted to the cooler climate of northern regions, such as the Grey Mountain Carpet appear to be retreating in distribution. This species has experienced a 81% decrease in distribution between 1970 and 2016.
The breakdown in our climate is altering the ecology of our moths and their success. Whilst there are winners, expanding their range and populations, there are many more losers. A warming climate should assist many species, but the rate of change and the fragmentation of suitable habitats appears to impacting their ability to adapt.
Moths have evolved to synchronise their life-cycles with that of their food-plants. The earlier emergence of leaves due a warming climate appears to be impacting some species. Other moths are adapting to emerge earlier and some to having two generations in a year, potentially putting them in direct competition with others, less adapted to change. Population increases are not always a good thing without understanding the the full ecological consequences.
There is evidence of moths moving both northwards (latitude) and upwards (altitude) to remain in their optimal temperature window, in response to a changing climate. Species such as the Devon Carpet, which as the name suggests was a species of southern England as been moving north at a rate of almost 10 miles per year and is now being recorded in North Antrim and central Scotland.
Things will get worse when moths reach North Antrim there is not much room to move. Further studies have found species that are restricted to the northern parts of Britain and Ireland, such as the Scarce Sliver-Y, have declined significantly, in a way that is consistent with a climate change explanation. Equally species formally with a more southerly distribution are increasing and expanding their range.
Simply moving into a new area may not be perfect. Suitable foodplants may be scarce, as they are likely to adapt to change much more slowly and species may be increased competition as species may be forced to fill the same ecological niche.
A warmer and wetter climate may have other impacts, for example of on larval and pupa survival rates. There is evidence that some moth larvae are adapted to long, frosty winters, with a warmer climate may result in greater losses due disease, parasites and fungal infections.
Longer term there may be significant habitat changes, with impacts on food plants, shade, vegetation fires and greater economic pressures on the land, all of which our moths will have to contend with.
Moths have evolved to synchronise their life-cycles with that of their food-plants. The earlier emergence of leaves due a warming climate appears to be impacting some species. Other moths are adapting to emerge earlier and some to having two generations in a year, potentially putting them in direct competition with others, less adapted to change. Population increases are not always a good thing without understanding the the full ecological consequences.
There is evidence of moths moving both northwards (latitude) and upwards (altitude) to remain in their optimal temperature window, in response to a changing climate. Species such as the Devon Carpet, which as the name suggests was a species of southern England as been moving north at a rate of almost 10 miles per year and is now being recorded in North Antrim and central Scotland.
Rapidly moving north and the west the Devon carpet recently reached North Antrim. Whilst it is nice to see new species the factors driving these changes is of concern,
Things will get worse when moths reach North Antrim there is not much room to move. Further studies have found species that are restricted to the northern parts of Britain and Ireland, such as the Scarce Sliver-Y, have declined significantly, in a way that is consistent with a climate change explanation. Equally species formally with a more southerly distribution are increasing and expanding their range.
The Scarce Silver Y has suffered a 69% reduction in abundance and 71% shrinkage in distribution in Britain in recent decades
Simply moving into a new area may not be perfect. Suitable foodplants may be scarce, as they are likely to adapt to change much more slowly and species may be increased competition as species may be forced to fill the same ecological niche.
A warmer and wetter climate may have other impacts, for example of on larval and pupa survival rates. There is evidence that some moth larvae are adapted to long, frosty winters, with a warmer climate may result in greater losses due disease, parasites and fungal infections.
Longer term there may be significant habitat changes, with impacts on food plants, shade, vegetation fires and greater economic pressures on the land, all of which our moths will have to contend with.