Experimental evidence for optimal hedgerow cutting regimes for brown hairstreak butterflies

Published source details Staley J.T., Botham M.S., Amy S.R., Hulmes S. & Pywell R.F. (2018) Experimental evidence for optimal hedgerow cutting regimes for brown hairstreak butterflies. Insect Conservation and Diversity, 11, 213-218.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Manage hedgerows to benefit wildlife (e.g. no spray, gap-filling and laying) Action Link

Manage hedgerows to benefit wildlife (e.g. no spray, gap-filling and laying)

A replicated, randomized, paired, controlled study in 2010–2015 on a farm in Devon, UK (Staley et al. 2018, same experimental set-up as Staley et al. 2016) found that hedges which were cut once every two or three years in autumn, and allowed to increase in size with each successive cut, had more brown hairstreak Thecla betulae eggs than hedges cut every year, in winter or to a standard size. Over four years, the total abundance of eggs on hedges cut to allow incremental growth (5–12 eggs) was higher than on hedges cut to a standard size (2–6 eggs). When cut in autumn, there were more eggs on hedges cut once every three years (6–12 eggs) than on hedges cut every year (2–6 eggs). Hedges cut once every two (3–11 eggs) or three (6–12 eggs) years in autumn had more eggs than hedges cut every two (3–5 eggs) or three (3–6 eggs) years in winter. Hedges which were not cut for five years had a total of 5 eggs on average. In January–February 2010, three 195-m-long hedges were cut. From September 2010, the hedges were divided into thirteen 15-m sections, to which each combination of three sets of management options were applied for five years: cut once every one, two or three years; cut in September or January/February; and cut to the same dimensions or with the cutting bar raised by 10 cm on each successive cut. A section at the end of each hedge was left uncut throughout the experiment. In February–March 2012–2015, brown hairstreak eggs were surveyed by searching all blackthorn stems and shoots in the central 10 m of each hedge section for 20 minutes on each side of the hedge.

(Summarised by: Andrew Bladon)