SSSI: Unit 1
Unit 1 of the SSSI is referred to as the northern meadows. It is accessed from a short footpath off of the link road between West Mill Crescent and Wessex Oval at Carey. As you enter the Common via the kissing gate the land you see before you is the SSSI but only as far as the drainage ditch halfway towards the river; this is the ditch with the concrete bridge over it.
This is the most distant part of the SSSI from the river and shows more of the influence of acidic drainage water rather than the alkaline river flood area on the other side of the ditch. This means the habitat on either side of the ditch is different; that may not be immediately obvious until you take the time to stop and look.
In the SSSI area, jointed rush and soft rush are abundant with occasional Purple Moor-grass. Carnation Sedge and Common (or black) Sedge are frequently found as well the flowers of devil’s-bit scabious and meadow thistle. Of particular interest, and one of the main reasons for notification as an SSSI is the presence of the nationally scarce whorled caraway, known only from one other Dorset site. There is also an abundance of the rare moss Climacium dendroides in the sward. In spring the cuckooflower is common here which attracts numbers of orange-tip butterflies and later in the summer greater bird’s-foot trefoil can be found.
The ditches are worth looking at when crossing for various species of damselfly and dragonfly.
Little of the flora listed is found on the non-SSSI part of the Common on this side of the railway embankment.
The 2010 survey reported that the south-east compartment near the railway line required increased management including grazing to reduce rank and tussocky growth. Overall the condition of the block is unfavourable due to the extent of shading of the ditches by sallows, alders and gorse, and also by the extent of macroalgae.
SSSI Unit 2
If you stand on the gravel car park by the hospital and look out towards the bypass the land between you and the bypass and between the gravel track to the farm across to the river is SSSI unit 2, the eastern block. This is the block nearest to the town and is vaguely triangular in shape. It is bordered on its northern side by the river and on its western side by the bypass embankment. A large drainage ditch provides the southern/eastern border which abuts up towards the town walls.
This enclosed area is usually very damp all through the summer months and is flooded for much of the winter months in most years. It is grazed by cattle throughout the summer and, until a few years ago, had horses grazing too.
Whilst some birds make use of the floods in winter, mostly black-headed gulls, the area is no longer suitable habitat for most bird species to consider nesting on.
The wet meadow has some flora but is mainly grassland dominated by Yorkshire fog and meadow fescue with crested dog’s-tail and creeping bent also present.
The main interest lies in the drainage ditch and neighbouring meadow fringes where cuckooflower, marsh-marigold and ragged robin seem to thrive. The ditch has many other species too including the scarce nodding bur-marigold along with water forget-me -not, water dock and many more. The ditch is also the prime area for invertebrate life including various species of odonata (dragonflies and damselflies) and orthoptera (grasshoppers and bush crickets).
The river is not part of the designated SSSI but also has an array of flora along its edges.
When surveyed in 2010 Natural England recorded that the terrestrial part of the unit was in favourable condition, but the unfavourable condition of the ditch merits an overall unit assessment of unfavourable recovering. The grassland is in favourable condition with good levels of grazing by cattle and horses. However, this area is no longer grazed by horses.
SSSI Unit 3
The western-most grassland, unit 3, lies to the west of the railway and to the south of the river. It is the most heavily influenced by the underlying acidic soil and supports a ‘fen meadow’ community of plants.
In the damp area purple moor-grass is abundant and quaking grass, heath grass and sweet vernal grass are all frequent. Common sedge, carnation sedge and yellow sedge are also common in the low lying marshy areas. There is a good deal of interesting flora here too devil’s-bit scabious, lousewort, marsh pennywort and bog pimpernel all present in some quantity. The lower lying areas have the scarce marsh cinquefoil and the more acidic character of the soil is reflected in the local occurrence of various bog sphagnum mosses. Here too, as a result of the acidic influence you find round-leaved sundew and small quantities of cross-leaved heath and petty whin.
Comarum palustre - Marsh Cinquefoil
On the higher and drier acid grassland on the southern slopes the flora is low in diversity but well-grazed and features frequent common sorrel and autumn hawkbit. There are occasional areas of early hair-grass, mouse-ear hawkweed and heath grass. Easily overlooked are patches of the diminutive and rare birdsfoot as well as procumbent pearlwort. Sand spurrey is locally frequent on the gravel track
When surveyed in 2010 the terrestrial habitats were in favourable condition but the unit overall was in unfavourable recovering condition due to the ditches. The species diversity and indicators of local distinctiveness were favourable, but the unit was overall unfavourable due to the extent of shading of the ditches by scrub, in particular by sallows, brambles, gorse and alder, and also in some places by tall herbs and rushes.
Non-SSSI Areas
The river Piddle has the most natural interest but is excluded from the SSSI
Having considered the three units that are designated SSSIs what about the rest of the common?
The most obvious feature outside of the SSSI units is the river; despite having some special plants but I think only areas of land can be designated as SSSI. The Piddle (or Trent) rises in the chalk hills in the heart of Dorset. Chalk streams and rivers are quite a rare habitat internationally and the majority are in the south of England and two, the Piddle and the Frome, reach the sea at Wareham. In the river the scarce river water-dropwort grows in some quantity and in places where the flow is fast chalk-stream water-crowfoot can be found. The yellow water-lily is our only native water-lily and can be seen in various places especially near the west mill. Along the edges of the river brooklime, water figwort, water mint and water speedwell grow and hemlock water-dropwort and hemp-agrimony are quite abundant in places. Bulrush and reed sweet-grass are two of the more interesting ‘grass’ species along the shallow river edges.
Drainage ditches are present in all three sections of the SSSI but also occur in the non-SSSI areas as well. To the south of Unit 1 and they contribute to the floristic interest of the common with various significant plants occurring including sneezewort, gipsywort, purple loosestrife, meadowsweet, water plantain, water chickweed and some occasional marsh valerian. The invasive Indian balsam is well established at the western end of this area.
Also in the southern part of the Carey section, adjacent to unit 1 between the SSSI and the river meadow buttercup is abundant and puts on a glorious show in May each year. Marsh horsetail is also well established here along with marsh ragwort.
Being influenced by farming activity, along the established tracks and around the edge of the common you will see various ‘weeds of cultivation such as knotgrass, pineappleweed, red-deadnettle and black nightshade.
At the eastern end of the common, the land to the north of the river is largely tussock grass and rush and is largely inaccessible whilst the area between the road and the railway is the farm and the mill with just a few hedgerow plants to be found including hedge woundwort (often mistaken for an orchid), hedge bindweed, dog-rose and some shrubs such as hawthorn and blackthorn.
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