BUTTERFLIES AT HENSTEAD 1997–2002
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CHANGES IN THE NUMBER OF BUTTERFLIES VISITING A GARDEN IN NORTH-EAST SUFFOLK, 1992–2007 PETER J. DARE Introduction The Suffolk butterfly fauna, past and present, has been well documented in recent years by means of distribution atlases (Mendel & Piotrowski, 1986; Stewart, 2001) and transect counts in breeding habitats while Stewart (1994, 1995) published the results from a county-wide garden survey. The annual surveys of garden butterflies and their preferred nectar plants organized by Butterfly Conservation reflect the rapidly growing interest in the hobby of ‘butterfly gardening’. Indeed, gardens now afford an increasingly important habitat for many butterflies, especially in counties such as Suffolk where so much natural habitat has been destroyed by agricultural and other developments (Stewart, 2001). A Suffolk survey in 1994 documented the relative frequency with which 31 species visited a sample of 152 gardens, as well as listing those plants observed to be most important either as nectar sources or for breeding (Stewart, 1995). For 16 years from 1992 I systematically counted the numbers of butterflies visiting our small rural garden in north-east Suffolk at Henstead (TM496859) located 4 km from the North Sea coast. This article summarises results from a simple, but semi-quantitative, recording scheme. It shows how this could be used more widely to measure how our garden butterfly populations change both seasonally and, perhaps more importantly for conservation, how they fluctuate in abundance between years. Garden Features The 0·3 acre garden is very sunny but rather exposed to easterly winds. Arable land adjoins the east side whereas hedges, scattered trees and neighbouring gardens afford reasonable protection from other winds. Several deciduous spinneys are within 0·5–1 km and two extensive deciduous woodlands within 5 km. Nearby to the north there are water meadows along the narrow Hundred River. The garden comprised lawns (with weeds), flower beds, two small shrubberies plus scattered bushes of lilac, rose, elder, Ribes, dogwood and broom. There were several tall trees – a massive snow gum (Eucalyptus sp.) and young sycamores (2), oaks (2), ash (1) and a large wild pear. Also providing shelter for butterflies were a low hedge of Spiraea, hawthorn and other bushy growth along the exposed field edge; a long tall hedge of thickly ivy-covered young (partly diseased) elms; a long ivy-covered wooden fence; and small ‘wild’ patches of nettles, rough grasses and mixed crucifers, umbellifers and so on. Over the first 5–10 years, we increased the variety of nectar sources to span the butterfly season. In particular, buddleias were allowed to spread, and we planted or encouraged Hebe shrubs (2), Escallonia, asters, ice-plants (Sedum), Aubretia, Salvia, thyme, oregano, lavender, catmint, honesty, Verbena bonariensis and other attractant flowers. Brambles and rough grassy verges occurred on the bank at the gate and along the lane. All the above flowers attracted butterflies except for the lavender.
Trans. Suffolk Nat. Soc. 44 (2008)