Bast bark beetle  (Ernoporus tiliae)

Classified as Endangered in Great Britain (3).

This small, brown bark beetle has scales covering the wing cases (elytra), some of which are raised and form rows (2).

Formerly, this species had a mainly western distribution in Britain, but it has also been found in Durham, Lincolnshire, Yorkshire, Leicestershire, Hertfordshire and Surrey. However it has suffered a prolonged decline, and is now found in just five sites, in Gloucestershire, Lincolnshire, Northamptonshire, and Norfolk (3). Outside of Britain, this beetle has a wide distribution throughout the Palaearctic region(3).

It typically occurs in broadleaved woodland and seems to prefer old coppiced woodlands that have a continuous supply of lime (3). It has also been recorded from mature parkland habitat (3).

This beetle lives in the bark of recently dead or dying twigs and small boughs of lime trees (genus Tilia), and particularly prefers small-leaved lime (Tilia cordata) (4).

The decline in coppice management of woodlands has contributed to the decline of this beetle, along with the loss of old lime woodlands and the widespread practice of 'tidying up' woodlands, by removing fallen or dying wood (3).

The UK Biodiversity Action Plan (UK BAP) lists the bark bast beetle as a priority species; the Species Action Plan that has been produced as a result of this prioritisation aims to maintain the number of sites that are occupied by the species, and increase their size (3). In addition, English Nature has included this beetle in its Species Recovery Programme.

For more on English Nature's Species Recovery Programme see:
http://www.english-nature.org.uk/science/srp/default.asp

• Coppiced: coppicing is a traditional form of woodland management in which trees are cut close to the base of the trunk. Re-growth occurs in the form of many thin poles. Coppiced woodlands are cut in this way on rotation, producing a mosaic of different stages of re-growth.
• Elytra: in beetles and earwigs, the hard fore wings. They are held aloft when the insect flies, and are often coloured or patterned.
• Palaearctic region: the region that includes Europe, the part of Asia to the north of the Himalyan-Tibetan barrier, North Africa and most of Arabia.

1. National Biodiversity Network Species Dictionary (September 2002) http://www.nhm.ac.uk/nbn/
2. Joy, N.H. (1932) A practical handbook of British beetles. Volume 1. H. F. & G. Witherby, London.
3. UKBAP. (September 2002) http://www.ukbap.org.uk
4. Hymen, P. S. and Parsons, M.S. (1992) A review of the scarce and threatened Coleoptera of Great Britain: Part 1. JNCC, Peterborough.