Phenology and habitat availability determine responses to climate change among British butterflies and moths.

Climate change is causing shifts in the distribution of Lepidoptera in Britain1, with southern species expanding northwards at an increasing rate over the past 50 years2. Not all have responded equally, however, with habitat specialists, relatively sedentary species and those with decreasing population trends seemingly less able to colonise new areas despite the warmer conditions3,4.

Two new studies led by the University of York, in collaboration with Butterfly Conservation and other partners, have shed further light on the factors that promote or constrain responses to climate change among British butterflies and moths.

The first looked at the effects of changing phenology. As the climate has warmed, butterflies and moths have tended to fly earlier in the year5 and, in some cases, produce more generations each year6, but the implications of these changes for population size and persistence were unclear. The new research considered 130 species of butterflies and moths in Britain and showed, using data from the UK Butterflies Monitoring Scheme and Rothamsted Insect Survey, that phenological advance (i.e. emerging earlier in the year) was associated with increased population growth, but only in multivoltine species7. In such species, the earlier emergence of the first generation led to greater abundance in the second brood. The flight periods of univoltine (single-brooded) species also advanced significantly over a 20-year study period (1995-2014) but there was no clear relationship with abundance trends. Indeed, for those univoltine species that were also habitat specialists, earlier emergence was correlated with decreasing abundance. The authors concluded that the northward shifts of species driven by climate change are indirectly linked to advancing phenology via changes in abundance.

The second study quantified the effect of habitat availability on the ability of nearly 300 invertebrate species (including 16 butterflies and 116 macro-moths) to expand northwards in Britain over a 40-year period (1976-2015)8. It is obvious that for species to expand their ranges in response to climate change, there must be suitable habitat to colonise, and the lack of habitat in Britain’s intensively managed landscapes has often been proposed as the reason why many habitat specialists have failed to spread in recent decades3. Indeed, even for wider countryside species such as the Speckled Wood (Pararge aegeria), with relatively undemanding habitat requirements, habitat availability has been shown to limit range expansion9. The new analysis, drawing on recording scheme data (including from the Butterflies for the New Millennium project and National Moth Recording Scheme run by Butterfly Conservation), showed that the northward range expansion of all taxonomic groups studied lagged behind shifts in temperature. By measuring the habitat associations of species close to their northern range margin and then quantifying the area of suitable habitat in the landscape, the researchers showed that habitat availability was a major constraint on climate-driven distribution increase across many invertebrate species.

While it is self-evident that species will only be able to colonise areas that have recently become climatically suitable (due to climate warming) if appropriate habitats are available, it is important for evidence-based conservation to demonstrate that this is true across many British species. This new research proves the need for large-scale habitat restoration policies, such as the proposed Nature Recovery Network in England, to be rolled out across landscapes to enhance the resilience of most species to the uncertainties of future climate change.

Richard Fox

Associate Director Recording and Research, Butterfly Conservation.

  1. Hill, J.K., Thomas, C.D., Fox, R., Telfer, M.G., Willis, S.G., Asher, J. & Huntley, B. (2002) Responses of butterflies to 20th century climate warming: implications for future ranges. Proceedings of the Royal Society B 269:2163–2171. doi:10.1098/rspb.2002.2134

 

  1. Mason, S.C., Palmer, G., Fox, R., Gillings, S., Hill, J.K., Thomas, C.D. & Oliver, T.H. (2015) Geographical range margins of a wide range of taxonomic groups continue to shift polewards. Biological Journal of the Linnean Society 115:586–597. doi:10.1111/bij.12574

 

  1. Warren, M.S., Hill, J.K., Thomas, J.A., Asher, J., Fox, R., Huntley, B., Roy, D.B., Telfer, M.G., Jeffcoate, S., Harding, P., Jeffcoate, G., Willis, S.G., Greatorex-Davies, J.N., Moss D. & Thomas, C.D. (2001) Rapid responses of British butterflies to opposing forces of climate and habitat change. Nature 414:65–69. doi:10.1038/35102054

 

  1. Mair, L., Hill, J.K., Fox, R., Botham, M., Brereton, T. & Thomas, C.D. (2014) Abundance changes and habitat availability drive species’ responses to climate change. Nature Climate Change 4:127–131. doi:10.1038/nclimate2086

 

  1. Roy D.B. & Sparks, T.H. (2000) Phenology of British butterflies and climate change. Global Change Biology 6:407–416. doi:10.1046/j.1365-2486.2000.00322.x

 

  1. Altermatt, F. (2010) Climatic warming increases voltinism in European butterflies and moths. Proceedings of the Royal Society B 277:1281–1287. doi:10.1098/rspb.2009.1910

 

  1. Macgregor, C.J., Thomas, C.D., Roy, D.B., Beaumont, M.A., Bell, J.R., Brereton, T., Bridle, J.R., Dytham, C., Fox, R., Gotthard, K., Hoffmann, A.A., Martin, G., Middlebrook, I., Nylin, S., Platts, P.J., Rasteiro, R., Saccheri, I.J., Villoutreix, R., Wheat, C.W. & Hill, J.K. (2019) Climate-induced phenology shifts linked to range expansions in species with multiple reproductive cycles per year. Nature Communications 10:1–10. doi:10.1038/s41467-019-12479-w

 

  1. Platts, P.J., Mason, S.C., Palmer, G., Hill, J.K., Oliver, T.H., Powney, G.D., Fox, R. & Thomas, C.D. (2019) Habitat availability explains variation in climate-driven range shifts across multiple taxonomic groups. Scientific Reports 9:15039. doi:10.1038/s41598-019-51582-2

 

  1. Hill, J.K., Collingham, Y.C., Thomas, C.D., Blakeley, D.S., Fox, R., Moss, D. & Huntley, B. (2001) Impacts of landscape structure on butterfly range expansion. Ecology Letters 4:313–321. doi:10.1046/j.1461-0248.2001.00222.x