Rook Clift
Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| SU819182 | — | Unfavourable Declining | 10.68 | 2024-03-22 |
Geology & landscape
Rock Type: Chalk
Description
Description Rook Clift is a small wooded combe on the scarp slope of the South Downs. The soils are predominantly calcareous in nature, overlying the chalk of the Downs. Deeper soils occur at the foot of the slope and also the course of a stream, arising within the wood. This site is an ancient woodland which remains in a semi natural condition. Large leaved lime Tilia platyphyllos dominates the canopy, together with ash Fraxinus excelsior and some beech Fagus sylvatica. Large leaved lime is a nationally scarce tree, with its natural range concentrated on the limestones of the Wye Valley and Peak District. Thus the high concentration of mature coppice stools, occurring on chalk, make this site nationally important and unique within West Sussex and the South Downs Natural Area. The canopy of large leaved lime, together with some beech casts a heavy shade and as a result the shrub layer is poorly developed with scattered whitebeam Sorbus aria and yew Taxus baccata. The field layer is dominated by vernal species such as ramsons Allium ursinum and bluebell Hyacinthoides non-scripta, or shade tolerant species including dog’s mercury Mercurialis perennis, spurge laurel Daphne laureola and sanicle Sanicula europaea. The steep sided valley around the steam is more open with a canopy dominated by ash and wych elm Ulmus glabra. Here the field and ground layers are more developed with stands of hart’s tongue fern Asplenium scolopendrium and soft shield fern Polystichum setiferum abundant and opposite leaved golden saxifrage Chrysosplenium oppositifolium common along the stream side. The ground layer consists of a bryophyte community more commonly associated with western woods including Thamnobryum alopecurum, Eurhynchium striatum, Fissidens taxifolius and Plagiomnium undulatum. This wood also supports a rich mollusc fauna including the Red Data Book species Helicondonta obvoluta and several which are indicative of ancient woodland.
Species mentioned
Show the 19 species mentioned in the description, with red-list statusPlant communities
A9 — Fast flowing river and stream, Marginal and inundation, Pond ditch and canal, Sluggish river and stream
Potamogeton natans community
Show 20 indicator speciesSchoenoplectus lacustris, Juncus bulbosus, Sparganium angustifolium, Sparganium erectum, Sparganium minimum, Alisma plantago-aquatica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Elodea canadensis, Lemna minor, Lemna trisulca, Nymphaea alba, Callitriche platycarpa, Callitriche stagnalis, Littorella uniflora, Potamogeton natans, Ranunculus trichophyllus, Glyceria fluitans, Chara subspinosa
A14 — Fast flowing river and stream
Myriophyllum alterniflorum community
Show 15 indicator speciesIsolepis fluitans, Juncus bulbosus, Fontinalis antipyretica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Lemna minor, Callitriche stagnalis, Littorella uniflora, Potamogeton filiformis, Potamogeton gramineus, Potamogeton natans, Ranunculus peltatus, Chara spp., Nitella hyalina
A17 — Chalk river and stream, Fast flowing river and stream
Ranunculus penicillatus ssp. pseudofluitans community
Show 11 indicator speciesBerula erecta, Nasturtium officinale, Elodea canadensis, Lemna minor, Callitriche stagnalis, Veronica beccabunga, Polygonum amphibium, Polygonum hydropiper, Potamogeton crispus, Potamogeton pectinatus, Ranunculus penicillatus ssp. pseudofluitans
A18 — Fast flowing river and stream
Ranunculus fluitans community
Show 12 indicator speciesFontinalis antipyretica, Fontinalis squamosa var. curnowii, Myriophyllum alterniflorum, Myriophyllum spicatum, Elodea canadensis, Mentha aquatica, Lemna gibba, Lemna minor, Potamogeton perfoliatus, Ranunculus fluitans, Glyceria fluitans, Phalaris arundinacea