TRANSACTIONS SOME OBSERVATIONS O N THE FLORA OF THE MARGINS OF THE A12 W . J . PLUMB
Introduction DR. Way (1970) has suggested that the verges of motorways can act as important reservoirs of wildlife. H e points out that one mile of motorway absorbs twenty acres of land, 40% of which is verge or bank, and is sown with a basic seed mixture and provides a linear habitat of considerable ecological value because it transects many habitats. It is protected by virtue of its nature and constancy of management could easily be arranged. Dr. Way argues that no other function has been proposed for the motorway verges but also that people cannot inspect and enjoy wildlife on a motorway and the verges are too new quickly to become areas of outstanding biological interest. Since older verges have had a fairly constant degree of management over a longer period of time it would be reasonable to expect them to support a richer and more stable flora than the relatively new verges of the motorways. T h e principle aims of the present study were to investigate the effectiveness of the verges of the A I 2 as reserves for wild plants and to examine the factors which may determine the distribution of the flora on the verges. T h e account may also act as a starting point for the fuller documentation of the flora of Suffolk's roadside verges. There appears to be very little recorded information on this important habitat although Pierce and Ranson (1971) gave a good general account and included a list of those Suffolk verges meriting specific conservation measures. Methods An approximately seven mile Stretch of the A I 2 south-west of Ipswich was chosen as the area for study. A survey was made of the Vegetation at five sites each chosen as having different characteristics to give a representative cross-section of the habitats transected by the carriageway. Each site consisted of an approximately fifty yard Stretch of the carriageway, the total area of road margin examined amounting to little more than one acre. T h e distribution and abundance of each species was recorded and an attempt was made to relate these observations to the following features: (a) management, (b) adjoining land use, (c) width and slope of verge, (d) encroachment of scrub, (e) effect of salt and lead residues and m u d spray on the Vegetation at the edge of the verge, (/) soil types, (g) age of verge.