The above grass looked rather pretty in the sunlight when came across it at the edge of woodland at Cheddar Gorge last year. In light of my previous plant profile of the Harebell, Campanula rotundifolia, I am now inclined to view its presence somewhat suspiciously. Atmospheric nitrogen is blamed for the decline in the Harebell, while Wood Small-reed is on the increase and recognised as a nitrogen-loving grass.
The Green brothers describe the Wood Small-reed, Calamagrostis epigejos, as frequent in Somerset’s damp woods, wood margins, hedge banks and verges. They noted an increase in the south of the county and that it forms large stands in areas of cleared woodland. The latter description seems to fit in with the area in which I discovered it. It was thriving and towered above me in height. Now, I know why there weren’t many Harebells. They had been crowded out.
Conservation is never that simple. A balance is necessary. I may have missed abundant Harebells, but butterflies were in great abundance. I could barely walk a step without a fluttering of wings taking to the sky. It brought back delightful memories of similar, almost forgotten experiences in childhood.
Butterflies and Grasses
The path was obscured by that other regularly loathed species, Bracken, Pteridium aquilinum. It provides important vegetation cover. Speckled Wood Butterflies, Pararge aegeria, were particularly in evidence. They feed on grasses, especially Cock’s-foot, Dactylis glomerata and Common Couch, Elytrigia repens. They favour damp areas where the grasses used as larval food plants grow tall and lush – the very habitat that our beloved Harebell dislikes.
Improved Recording, Decline in Grazing
The BSBI Atlas confirms the increase in Wood Small-reed. It suggests that some of the change might be put down to better botanical recording since 1962. A comment by Roe backs this up, as he noted that some records were mistakenly attributed to Calamagrostis canescens, Purple Small-reed, in the past. Otherwise, the increase can be attributed to changes in land management practices, especially a relaxation in grazing.
Yellow Rattle offers an Answer
Hubbard observes that British Calamagrostis species have no value for grazing at all. So beyond helping butterflies, what value does this species have beyond its appealing feathery look? A German study reveals its successful use with mowing to cover a sandy landfill site. Of course, the other way to curb the thuggish tendencies of grasses is to plant Yellow Rattle, Rhinanthus minor, and let other plants compete more fairly.
References and Further Reading
- BSBI (2020): Calamagrostis epigejos. Online Atlas of the British and Irish Flora. Last accessed 12 August 2020.
- Cope, Tom & Gray, Alan (2009): Grasses of The British Isles. BSBI Handbook No. 13. Botanical Society of the British Isles. London. (pp. 357-9).
- Eeles, Peter (2019): Life Cycles of British & Irish Butterflies. Pisces Publications. Newbury, Berkshire, UK.
- Green, Paul R. Green & Green, Ian P. & Crouch, Geraldine A. (1997): The Atlas Flora of Somerset. (self-published). (p. 241).
- Holub, Petr et al. (2012) Different nutrient use strategies of expansive grasses Calamagrostis epigejos and Arrhenatherum elatius. Biologia 67, 673–680 (2012). https://doi.org/10.2478/s11756-012-0050-9
- Hubbard, C. E. (1984): Grasses. A Guide to their Structure, Identification, Uses and Distribution in the British Isles. Third Edition revised by J. C. E. Hubbard. Penguin. London. (pp. 282-3).
- Lehmann, Cornelia & Rebele, Franz (2002): Successful management of Calamagrostis epigejos (L.) Roth. on a sandy landfill site. Journal of Applied Botany and Food Quality 76:77-81. August 2002.
- Plantlife (2020): How to grow Yellow Rattle (Rhinanthus minor). Last accessed 12 August 2020.
- Roe, R. G. B (1981): The Flora of Somerset. Somerset Archaeological and Natural History Society. Taunton. Somerset. (p. 295).
- Rose, Francis (1989): Colour Identification Guide to the Grasses, Sedges, Rushes and Ferns of the British Isles and north-western Europe. Viking. London. (pp. 144-45).
- Sterry, Paul & Cleave, Andrew & Read, Rob (2016): Complete Guide to British Butterflies & Moths. William Collins. London.