Things are no better in the United States, where the Xerces blue butterflies have not been seen flying over the Californian beaches for eighty years. The Xerces blue, which once crowded the sand dunes of the San Francisco coast, has been declared virtually extinct; the same fate now seems to await the Monarch of the family Nymphalidae, especially where it lived alongside intensive crops.
In Italy, recent research has produced the “IUCN Red List of Italian Rhopalocera”. As many as 288 native species of diurnal lepidoptera have been recorded, to which is added one species of South African origin accidentally introduced into Italy.
One of these must already be considered extinct in our country: Lycaena helle, also known as the violet copper. At least 18 species, 6.3% of those examined, are seriously at risk of imminent extinction.
Let us turn to the causes.
Although it is not easy to rank them by importance, among the main ones are certainly changes in land use and agronomic practices.
At the same time, the abandonment of agro-silvo-pastoral activities, especially in the Apennine areas, is harming the whole ecosystem and, with it, the life of butterflies.
Alongside these phenomena there are undoubtedly fires. In recent years, species such as Polyommatus galloi, Hipparchia sbordonii Kudrna (the “Ponza butterfly”) and Spialia therapne have been particularly threatened by them.
Another cause of suffering is the withdrawal of water resources for agricultural use. The lowering of the water table that this causes alters the ecosystem of wetlands, for example in the Po Valley. This is a danger above all for the species Maculinea alcon.
To all this we must add the role played by climate change. Higher winter temperatures, and anomalous and irregular rainfall. Melitaea britomartis, widespread in northern Italy, is suffering enormously from the changed climate conditions.
Finally – though it almost goes without saying – there are more strictly human activities such as urbanisation, responsible for the extinction of various local species in the plains, and the use of pesticides, herbicides and insecticides.
Last but not least, an unhealthy collecting habit still survives (sadly, not only in jokes), estimated to be a danger to as many as ten species of butterflies in Italy.
In Great Britain, where the situation is perhaps even worse than ours, with 80% of butterflies estimated to be in decline, scientists have taken the initiative, asking citizens to help them track the northward migration of lepidoptera.
After examining 50 years of data, researchers at the non-profit organisation Butterfly Conservation, which runs the annual Big Butterfly Count, have identified a clear northward shift of many species, including garden favourites, the comma, the peacock and the holly blue.
Here too the cause lies in climate change, which has created warmer habitats, allowing some species to grow substantially. The red admiral, the one we know as Vanessa atalanta, typically found in southern England in summer before migrating to Europe for the winter, now lives in the United Kingdom all year round, with its population having tripled.
Meanwhile the holly blue has been sighted in Scotland, and has increased by 34%. The same phenomenon applies to the day-flying moth known as the Jersey tiger, previously observed only in south-west England and now sighted north of London during the Big Butterfly Count 2021.
What is the problem? As Dr Zoë Randle, senior surveys manager at Butterfly Conservation, explains, ‘Highly adaptable species are all able to move to new places as the climate warms, but for habitat-specific species, these trends raise serious alarm signals.’
‘Food plants cannot move the way butterflies can. Species that rely on particular habitats are not able to move freely. This means that, if climate change continues, they could become trapped in isolated fragments of remaining habitat, facing the very real threat of extinction.’
