Grassland Survey 2015 High Park the Blenheim Estate
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Grassland Survey 2015 High Park The Blenheim Estate Prepared by Thames Valley Environmental Records Centre Grassland Survey 2015 High Park Blenheim Contents 1 Background 3 2 Site description 3 Map 1. Site location 3 Survey method 4 4 Habitat descriptions 4 5 Evaluation & Recommendations 6 6 References 8 7 Appendices Appendix 1. Target notes 9 Appendix 2. Species lists 20 Appendix 3. Maps 28 Map 2. Habitat map - North Map 3 Habitat map – South Map 4. Target note location map - North Map 5. Target note location map – South Map 6. Habitats with Target note locations - North Map 7. Habitats with Target note locations – South Thames Valley Environmental Records Centre 2 Grassland Survey 2015 High Park Blenheim 1 Background This report covers a survey carried out at High Park, Blenheim following recommendations in the management plan (Wychwood Project, 2014) for further information on the grassland habitats present. It identifies and describes the grassland types occurring on the site and highlights the areas grassland of highest value for their botanical interest. 2 Site description High Park, Blenheim is located to the south west of Woodstock, Oxfordshire at grid reference SP432155. The site is primarily parkland and woodland but includes open areas of bracken and grassland. It is a Site of Special Scientific Interest for its parkland habitat including numerous veteran oaks and significant deadwood invertebrate interest. The geology of the site is complex with bands of limestone, mudstone and sandstone. There is superficial sand and gravel to the northwest. It is approximately 70-120 metres above sea level. The study area covered in this survey is approximately 129 hectares. Map 1. Site location map Thames Valley Environmental Records Centre 3 Grassland Survey 2015 High Park Blenheim 3 Survey Method The survey focused on open areas of the site with grassland habitat. Surveys were carried out on 15th and 16th June 2015 using a Phase 1 based methodology (JNCC, 2010). This is a good time of year for surveying grassland. It is worth noting that whatever time of year a site is visited, not all species that occur on a site will be recorded in a single survey. Plant species lists were recorded for the main types of grassland and can be found in Appendix 2. An estimate of the relative abundance of each species was made using the DAFOR scale. The DAFOR scale ranks species according to their relative abundance within a particular area of vegetation and bare no relevance to the status of the species in the wider landscape. The following abbreviations are used; D – dominant, A – abundant, F – frequent, O – occasional, R – rare. In this survey, the prefix L – locally is also used. 4 Habitat descriptions Maps 2, 3, 6 and 7 in Appendix 3 show the location and extent of the grassland habitats. Due to the prevalence of habitat mosaics and transitions, habitat boundaries are approximate and patches of habitat less than 0.1ha are not usually mapped separately. However, some smaller pockets of unimproved acid (wet) grassland have been mapped as additional detail on their location was considered useful. The target notes provided in Appendix 1 give additional detail on the vegetation at the specific locations show on Maps 4 and 5 in Appendix 3. General The grassland in the surveyed area is limited in extent due to the dominance of bracken over most open areas of the parkland. Small areas occur in glades and along paths with larger blocks to the northwest and along wider rides. The varied geology of the site has created a mixture of acid, neutral and calcareous swards. There are mosaics and transitions between these grassland types. Bracken is abundant in northern and central areas and, where it is less dominant, forms mosaics with grassland vegetation. There are also transitions between wetter and drier conditions, and between finer and ranker swards. Woodland species including bluebell, wood avens, dog’s mercury and false-brome are also locally frequent in some swards. Unimproved (dry) acidic grassland There is unimproved acid grassland at the western end of the ride at Target note 11, at Target notes 5.1, 5.2, 5.3 and small patches along paths at Target note 12. It has a fine sward of red fescue, sweet vernal-grass and Yorkshire fog with locally frequent creeping soft-grass. It is rich in broadleaved herbs including pignut, tormentil, heath bedstraw and crosswort. There is also lesser stitchwort, black medick, germander speedwell and red clover. There is locally frequent bracken and small amounts of cat’s-ear and heath speedwell. It has affinities to the NVC community U4 Festuca ovina – Agrostis capillaris – Galium saxatile grassland. In areas of grassland where bracken is more abundant the vegetation has affinities to U20 Pteridium aquilinum – Galium saxatile community, Anthoxanthum odoratum sub-community. Unimproved (wet) acid grassland Acid grassland on wetter ground is found at Target notes 8 and 10. It occurs in small patches amongst bracken and more neutral grassland. It includes locally abundant Thames Valley Environmental Records Centre 4 Grassland Survey 2015 High Park Blenheim Yorkshire fog, creeping soft-grass, sweet vernal-grass, hairy sedge, bugle, heath bedstraw, pignut, tormentil, selfheal, meadow vetchling, greater bird’s-foot trefoil and ground ivy. It also includes crosswort, germander speedwell, lesser stitchwort and common spotted- orchid. Wetter conditions are indicated by soft rush, compact rush, hard rush, tufted hair- grass, marsh thistle, meadowsweet, creeping-Jenny, water mint, skullcap and common marsh-bedstraw. Unimproved neutral grassland (with transitions to more calcareous and acidic communities) Unimproved neutral grassland is found at Target notes 4.8, 4.9, 4.10, eastern areas of the ride at Target note 11 and at Target note 23. It is locally dominated by false oat-grass, rough meadow-grass, Yorkshire fog, meadow foxtail, red fescue, creeping bent and false- brome with smooth meadow-grass, cock’s-foot and meadow fescue. There are smaller amounts of perennial rye-grass, crested dog’s-tail and tufted hair-grass. Broadleaved herbs include lady’s bedstraw, creeping cinquefoil and germander speedwell with selfheal, silverweed, red clover, white clover, crosswort, meadow vetchling, wood avens, yellow rattle, perforate St. John’s-wort and black medick. There are small amounts of adder’s tongue, pignut and common spotted-orchid. Some areas include tall ruderal species such as nettle and creeping thistle and, in places, it occurs in mosaic with bracken. Wetter areas include marsh thistle, greater bird’s-foot-trefoil, soft rush, ragged-robin, compact rush, bugle and wild angelica. Ranker swards of false oat-grass have affinities to the NVC community MG1 Arrhenatherum elatius and richer areas include elements of MG5 Cynosurus cristatus- Centaurea nigra grassland. Semi-improved neutral grassland It is locally dominated by false oat-grass, meadow fescue and rough meadow-grass with locally abundant red fescue and Yorkshire fog. Other grasses include cock’s-foot, perennial rye-grass, meadow foxtail, false brome, sterile brome and tufted hair-grass. Broadleaved herbs include silverweed, selfheal, wood dock, enchanter’s-nightshade, dog’s mercury, ground ivy, creeping buttercup, creeping cinquefoil, germander speedwell and common comfrey. Tall ruderal species include locally abundant nettle with some creeping thistle and hogweed. Unimproved calcareous grassland (including rank grassland and transitions to more neutral swards) To the southern end of the site at Target note 4, there are small areas of grassland with calcareous character. The sward is rough with high abundance of ranker grasses including tor-grass and false oat-grass. This grassland occurs in small pockets amongst parkland trees and scrub, rougher more neutral grassland and areas of nettle. There are locally abundant anthills. Broadleaved herbs include lady’s bedstraw, crosswort, common bird’s- foot trefoil, hairy violet, germander speedwell, ground ivy, barren strawberry and yellow rattle. There are also small amounts of eyebright and common rock-rose. Areas dominated by tor-grass have affinities to the NVC type CG4 Brachypodium pinnatum grassland. The species-rich areas tend to be transitional to more neutral swards. To the north at Target note 19, there is a calcareous (to neutral) grassland bank. It is dominated by rough meadow-grass and red fescue with sweet vernal-grass, Yorkshire fog and a mix of other grasses including tor-grass, cock’s-foot, false oat-grass, soft brome and meadow fescue. Broadleaved herbs include pignut and crosswort with yellow rattle, cowslip Thames Valley Environmental Records Centre 5 Grassland Survey 2015 High Park Blenheim and meadow buttercup. There are smaller amounts of creeping buttercup, creeping thistle, germander speedwell, common sorrel, meadow vetchling, creeping cinquefoil, tormentil, lady’s bedstraw, common twayblade and lesser stitchwort. Bracken Extensive stands of bracken are present across central and northern areas of the site. Some open areas of the parkland are almost exclusively bracken with small amounts bramble, bluebell and other woodland herbs. Other areas have a more open nature with mixture of bracken and grassland species. 5 Evaluation & Recommendations The following evaluation is an assessment of the grassland on the site, highlighting the areas of greatest botanical interest and includes some recommendations for management. Evaluation Naturalness Grassland habitat on the site includes examples of three ‘Habitats of Principal Importance’ included in Section 41 of the Natural Environment and Rural Communities (NERC) Act 2006. These are Lowland calcareous grassland, Lowland meadow and Lowland dry acid grassland. These habitats are a priority for conservation in England. The Lowland calcareous grassland found on the site is a species-poor, tor-grass dominated community. A wider range of species are found in the more neutral transitional swards that fall outside the priority habitat definition. There are small areas of Lowland dry acid grassland that form a reasonable example of the priority habitat.