The grassland and list of species

Acknowledgement 

This material is taken from the Hurst Water Meadow Site Management Plan 1996-2000, produced by Isabel Jones, Mark Stevenson and Steve Gregory for the Northmoor Trust (Director Dr Steve Head) to all of whom the trustees are deeply indebted.

Communities 

The National Vegetation Classification (NVC).

The NVC, initiated by Lancaster University uses records from over 35,000 samples of vegetation to describe plant communities from all natural, semi-natural and major artificial habitats in Great Britain. Each community is assigned a code. The code consists of one or two letters relating to the broad community type (e.g. MG for mesotrophic grassland of H for heathland), and a number which distinguishes sub-divisions of these broad communities. For example, mesotrophic grasslands are divided into 13 communities, MG1-13 (Rodwell 1992).

The NVC in relation to Hurst Meadow was used to provide a base-line survey upon which management decisions and future monitoring schemes could be based. It also allowed us to assess the site and place it in local, regional and national context.

Hurst Meadow

The site consists of a mosaic of habitats from aquatic and emergent vegetation along the riversides, damp ditches, short turf grassland, rank vegetation and remnant hedgerows. Numerous willows pollards border the ditches.

The small patches of wetland plants in the ditch line are of interest and may reflect a time when the ditch was in use. Botanically, all major habitats represented are impoverished and analysis of the survey results is difficult.

None the less two distinct communities are apparent.

MG7: Lolium perenne grassland / MG6: Lolium perenne - Cynosurus cristatus grassland

Much of the meadow is dominated by coarse grasses such as meadow foxtail (Alopecurus pratensis), cocksfoot (Dactylis glomerata) and rye grass (Lolium perenne) and is botanically impoverished. This suggests some form of agricultural improvement, either by application of inorganic fertiliser, herbicide and/or re-seeding. Overgrazing in the summer months could also lead to such impoverishment of the flora. 

Considering the absence of crested dogstail (Cynosurus cristatus) and the abundance of meadow foxtail in the survey samples, then the vegetation community which fits best is MG7d: Lolium perenne - Alopecurus pratensis grassland. This is a common component of riverside meadows and considered to be intermediate between the typical MG7 agricultural rye-grass leys and the more botanically rich MG6 grasslands (Rodwell 1992).

MG1: Arrhenatherum elatius grassland

Parts of the meadow have become invaded by false oat grass (Arrhenatherum elatius) which is indicative of an inconsistent grazing management. Associated coarse herbs such as cow parsley (Anthriscus sylvestris) and cleavers (Galium aparine) indicate that this is an MG1 community but the precise sub-community is not clear.

Environmental relationships which may have implications for management

The grassland community is typical of agriculturally improved or semi-improved pasture found on heavy, periodically flooded soils in the region. Ad-hoc grazing has further impoverished the sward and the implementation of consistent grazing management will be vital in increasing the site's value for wildlife. 

Previously identified as areas of particular interest, there are small patches of wet ground run with an old ditch line. Although periodically flooded, the ditches are beginning to silt up and for much of the year do not hold water. Encouraging a higher water level will give the aquatic species a greater area in which to become established. Grazing of the ditch margins would also prevent the domination by coarse vegetation. It would also create areas of bare mud and a variety of sloping and level margins, so encouraging invertebrates to the area (Kirby 1992, Biggs et al. 1994). In future, some dredging work may be necessary to maintain the ditches.

Areas with slightly more diverse wards

Notes: i). Frequency value (I-V). This gives the frequency of occurrence with which a species appears in the series of quadrats taken for each treatment. I is one quadrat in five; II is two in five etc. ii). Maximum cover (1-10). This gives the standard Domin value for the highest percentage ground cover recorded for each species. 1 = few individuals; 2 = several individuals; 3 = many individuals; 4 = 5-10% cover; 5 = 11-25%; 6 = 26-33%; 7 = 34-50%; 8 = 51-75%; 9 = 76-90% and 10 = 91-100%.

Rough grass areas - of lower botanical diversity

Flora especially trees and flowers (with list of species)

Flora

Vascular plants:

It appears that no detailed botanical surveys have been undertaken on the site. A site survey was undertaken in early May 1996 for this management plan (detailed records are given in Appendix 1). Other casual records were made in April and July of the same year. Around 60 species have been recorded, none of national importance, though a single specimen of Black Poplar (Populus nigra) on the north east boundary of the site is of note.

Much of the botanical interest is associated with the river banks and old ditch lines where species such as water dock (Rumex hydrolapathum), meadow rue (Thalictrum flavum) and cuckoo flower (Cardamine pratense) persist.

In several areas there are a number of notifiable weeds: Ragwort (Senecio jacobea), Broad-leaved Dock (Rumex obtusifolia), Spear and Creeping Thistle (Cirsium vulgare and C. arvense). If it is deemed that these are seriously affecting surrounding agricultural land (i.e. spreading), then by virtue of the 1959 Weeds Act, the Ministry for Agriculture, Fisheries and Food (MAFF) can serve notice to the occupiers and request that the species identified be removed.

Also worthy of conservation management are the ancient willow pollards. If left untouched, they will become top heavy and split apart, diminishing invertebrate and bird interest and making the site unsafe for visitors. In order to prolong the life of the pollard and maintain conservation interest the trees should be re-pollarded. Re-pollarding old and neglected trees can result in the death of the tree. Nonetheless, it is worth undertaking, particularly with willow. When re-pollarding trees that have been neglected, success may be greater if one or two of the major upright branches or a few of the smaller ones are retained in the first round of pollarding (Kirby 1992).

Species recorded 27th June 1996 Hurst Meadow

Plants recorded on the margin of the Mill-Stream

Plants found along margin of Buck Pool

Along River Thame - NW of Buck Pool

Other species recorded