The Thame Valley BOA covers an area of the Thame catchment between Waterperry and Princes Risborough, up to Stewkley and Hulcott.
Area Coverage: 3275 ha
Local wildlife sites: 16
Biological Notification Sites: 18
SSSI: 1
BAP Habitat:
Floodplain grazing marsh 120.7
Lowland meadows 54.5
Lowland wood-pasture and parkland 17.4
Purple moor grass and rush pastures 1.2
Traditional Orchard 1.4
Wet woodland 1.8
Rivers & Streams
The Thame Valley BOA forms the upper half of a wider connected landscape of riparian habitats of the Thame and important tributaries. The Thame Valley CTA is contiguous with the Thame Valley BOA on its southern edge, where Buckinghamshire and Oxfordshire meet, ensuring continuity of wetland habitats from the upper reaches of the Thame to its confluence with the river Thames at Dorchester-on-Thames. Connectivity between the BOA and CTA, and the main Thames river corridor, provides important opportunities for the dispersal of species moving north in response to climate disruption, such as Great White Egret (Ardea alba). The Thame Valley BOA covers the Thame river corridor between Waterperry and Haddenham.
The wetland habitats of this BOA are of primary importance for over-wintering and breeding waders, including Curlew (Numenius arquata), Lapwing (Vanellus vanellus) and Redshank (Tringa totanus). The planting of trees and woodland should avoid impacts on these nationally important species.
Joint Character Area
Primarily Upper Thames Clay Vales and the Midvale Ridge, with smaller areas of Chilterns and Bedfordshire & Cambridgeshire Claylands.
Landscape Types
Mostly agricultural unwooded land, with large areas of floodplain meadow and permanent pasture. Many sites along the main river are agricultural wetland. The Thame is a relatively deep, slow flowing, semi natural river, meandering for much of its length. Although runs and riffles occur only occasionally, river cliffs are more frequent. The floodplain of the Thame varies in width from less than 1km to several kilometres in places, often where tributaries join. Many of the tributaries’ watercourses possess a relatively natural channel morphology with frequent meanders, where they have avoided past modification / straightening. In places old river meanders can be seen in adjacent fields.
Geology
Predominantly mudstone and limestone interbedded, overlain by sand, silt and gravels. The arm along the Kingsey Cuttlebrook arises in the Grey Chalk sub-group of the Chilterns then, along with several other branches, travels across the Gault Formation and Upper Greensand Formation, then Portland Group before joining the main arm of the BOA as it flows across various Clay Formations. Some tufa springs /
seeps where Greensand outcrops exist between clay and chalk.
Topography
A wide gently undulating river valley, rising up the scarp slopes of the Chilterns along its south-eastern edge.
Biodiversity
Rivers and Streams, including Priority Habitat chalk streams – the river Thame and its tributaries support European Bullhead (Cottus gobio) and offer an important means for the distribution of many other species through the area.
Floodplain Grazing Meadow – there are extensive areas of floodplain meadow, often flanked by ridge & furrow fields, and home to rare plants such as Tubular Water Dropwort (Oenanthe fistulosa).
Lowland Meadows – there is a concentration of neutral grassland sites.
Wet woodland, fen and swamp – there are small but important patches of these rarer habitats across the BOA, and the area is a stronghold for native Black poplar (Populus nigra betulifolia).
Ponds – ponds scattered across the area support species including Common toad (Bufo bufo), Hairy dragonfly (Brachytron pratense) and stoneworts (class Charophyceae).
Reedbeds – a few areas of reed exist, important for birds such as the Red-listed Cuckoo (Cuculus canorus).
Wood Pasture and Parkland – There is potential parkland habitat at Tythrop House.
Hedgerows – There are concentrations of pre-18th century enclosure around Shabbington and these may contain species rich hedgerows.
Access
There are many public footpaths crossing the BOA.
Archaeology
There is ridge and furrow scattered across the area. There are three Registered Parks and Gardens – Eythrope Park, Mentmore and Hartwell House. There are 12 SAMs in the area.
Targets
Rivers and Streams – Management, Restoration
Floodplain Grazing Marsh – Management, Restoration
Lowland Meadows – Management, Restoration, Creation
Purple Moor Grass & Rush Pastures / Fen – Management, Restoration
Ponds – Management, Restoration, Creation
Wood Pasture & Parkland – Management, Restoration
Lowland Mixed Deciduous Woodland, and Wet Woodland–
Management, Restoration, Creation
Species-rich Hedgerows – Management, Restoration, Creation
Traditional Orchard – Management, Restoration
Reedbed – Management, Restoration, Creation
Places to visit:
There are many public footpaths crossing the BOA.
