The finding may appear initially appear counterintuitive for butterflies like warm weather. However, the issue is not just about warmer air; the effects of climate change (whatever the causes) are leading to periods of hot and dry weather. It is the loss of water habitats and other sources of available water that is the hardest hitting to butterfly populations. The Cabbage White and the Speckled Wood are particularly sensitive to these conditions.
The concern of biologists (a team led by Dr Tom Oliver from Nerc Centre for Ecology and Hydrology) is that drought-sensitive butterflies could disappear from the British countrywide by 2050, should temperature patterns continue at the same rate.
This concern is based on computer modelling that used climate conditions in 1995 as a starting point. During 1995 there was an atypical hot and dry summer. By using weather data and temperature, the researchers have extrapolated a line to the year 2100 and used 1995 data for the decline in butterfly numbers to predict future population numbers and the diversity of different species. The study found that extinctions of common species could begin as early as the year 2050.
The model predicts that the south-east of England would be worst affected.
Speaking with BBC Science, Dr Oliver noted: “”Butterflies are important culturally as part of our natural heritage, but there are other functions that could be impacted by their extinction including pollution, pest control and decomposition of waste.”
As a note of hope, the research team argues that if more butterfly habitats can become interconnected then the worst excesses of water loss can be avoided and this may see more butterfly species surviving. However, to do this requires proactive conservation work.
The findings have been published in the journal Nature Climate Change. The paper is headed “Interacting effects of climate change and habitat fragmentation on drought-sensitive butterflies.”
