Abundance

The butterfly monitoring scheme has contributed to these studies, showing that the abundance, phenology and annual fluctuations in the abundance of individual species of butterfly can be largely attributed to weather.

In general terms, numbers of butterflies are higher in, and immediately after, years with hot sunny summer weather, and lower during, and immediately following, cool wet summers.

In reality the situation is far more complex than this and individual species vary in their apparent response to particular weather factors. Some of these differences have been explored by Pollard (1988) and Roy et al (2001) and other publications listed below.

To find out more about what butterfly transect data tells us about the effects of climate change on abundance, see the following publications:

Pollard, E. (1988) Temperature, rainfall and butterfly numbers. Journal of Applied Ecology, 25, 819-828.

Pollard, E. (1991) Synchrony of population fluctuations: the dominant influence of widespread factors on local butterfly populations. Oikos, 60, 7-10.

Pollard, E. & Moss, D. (1995) Historical records of the occurance of butterflies in Britain: examples showing assocciations between annual number of records and weather. Global Change Biology, 1, 107-113.

Pollard, E., Greatorex-Davies, J.N., & Thomas, J.A. (1997) Drought reduces breeding success of the butterfly Aglais urticae. Ecological Entomology, 22, 315-318.

Roy, D.B., Rothery, P., Moss, D., Pollard, E., & Thomas, J.A. (2001) Butterfly numbers and weather: predicting historical trends in abundance and the future effects of climate change. Journal of Animal Ecology, 70, 201-217.

Roy, D.B. & Thomas, J.A. (2003) Seasonal variation in the niche, habitat availability and population fluctuations of a bivoltine thermophilous insect near its range margin. Oecologia, 134, 439-444.