Ithon Valley Woodlands

Also within

Powys County

Habitats

Ancient woodland, Fast flowing river and stream

Geology & landscape

Landscape processes: Fluvial

Birds & fish recorded

Birds

Description

Description The site is an important example of semi-natural mixed deciduous ancient woodland. It is relatively species-rich for woodland development on acid/neutral soils and contains uncommon plant species. The area is largely a plateau of level or gently east-facing slopes above the flood plain of the River Ithon. However, steeper ground occurs in the vicinity of the river and of east-flowing streams whose dingles dissect the plateau. The woodland is mainly open to grazing stock from the adjacent improved grassland, but in recent years the central area has been fenced out from stock. The woodland is varied in structure, with moderately grown maidens of sessile oak Quercus petraea being the dominant trees. However, the steeper slopes have a variable quantity of ash Fraxinus excelsior, and on poorly draining slopes the occasional alder Alnus glutinosa. The shrub layer is well developed, with abundant hazel Corylus avellana throughout, and other shrubs including holly Ilex aquifolium on the drier areas and guelder-rose Sorbus aucuparia on the lower slopes. Other tree and shrub species include rowan Sorbus aucuparia, birch Betula pendula and Betula pubescens, goat willow Salix caprea and hawthorn Crataegus monogyna. The drier areas are intermediate in character between the oak-birch-wood sorrel (Quercus-Betula-Oxalis acetosella) vegetation type and the more base-rich ash-rowan-dog’s mercury (Fraxinus-Sorbus- Mercurialis perennis) community. They are, however, probably closer to the former despite a generally well developed herb layer with wood avens Geum urbanum, enchanter's-nightshade Circaea lutetiana and sanicle Sanicula europaea. Honeysuckle Lonicera periclymenum is also well represented. In grazed areas, the ground layer is more grass-dominated, with abundant creeping soft-grass Holcus mollis and frequent male-fern Dryopteris filix-mas. The damp slopes are botanically varied since they include both flushed slopes and receiving sites. There are few clear boundaries between vegetation types, other than in association with topography. The wetter stands may be described as an alder-ash-yellow pimpernel (Alnus-Fraxinus-Lysimachia nemorum) woodland, but alder is not well represented and the stands merge into types with affinities to both the vegetation communities described above. Characteristic is the presence of more ash and some guelder-rose, and a herb-rich layer including bugle Ajuga reptans, opposite-leaved golden-saxifrage Chrysosplenium oppositifolium, remote sedge Carex remota and lady-fern Athyrium filix-femina. Locally uncommon species occurring in the varied area include broad-leaved helleborine Epipactis helleborine, herb-Paris Paris quadrifolia and, near the river, water avens Geum rivale. The site also includes two small areas of pasture close to the river. These provide shelter to a variety of insects, including common butterfly species such as meadow brown Maniola jurtina. The river bank provides nesting sites for sand martin.

Species mentioned

Plant communities