Fritillary 3

Fritillary

Fritillary 3

Publications

The Unique Ecosystems of the Oxfordshire Valley-head Fens

Celebrating the centenary of the first nature reserve in Oxfordshire
Multi-disciplinary research supporting conservation

An opportunity to read multi-disciplinary accounts of the origins, workings, diverse biology and conservation of these ecosystems which have hitherto not been understood.

Contents

  • New experimental and descriptive work on the nutrient requirements of the vegetation explains much of the unique nature of these habitats
  • Studies of the rare and characteristic invertebrates show how very special these sites are
  • Many important conclusions are made for the conservation of these fens
  • This approach represents a paradigm for the understanding and future sustainability of specific ecosystems
  • Vegetation history since the last ice age by Petra Dark
  • Hydrology by Peter Morris
  • New insights into the botany by Bryan Wheeler
  • The importance for invertebrates by Keith Porter
  • The southern damselfly by Graham Steven
  • Molluscs by Steve Gregory

Though the hard copy of this volume is still available, we have now made the papers available online; see below. Note that the page numbering differs between the printed version and the online version, the latter having been completely reformatted.

Contents

  1. Cover
    Originally published December 2000. Published online November 2023
  2. Editorial
    F. H. Watkins
    Originally published December 2000. Published online May 2023
  3. Introduction to the Valley-head Fens of Oxfordshire
    C. R. Huxley-Lambrick
    Originally published December 2000. Published online May 2023

    Summary...
    Certain fens of Oxfordshire have long fascinated the natural historian. They contain many interesting things:
    • the growth of peat in a limestone landscape
    • encrustations of marl (dispersed calcite)
    • the juxtaposition of acid-loving plants such as sundew, with plants only found in lime-rich conditions such as blunt-flowered rush
    • an unrivalled diversity of wetland plants, with such delights as devil’s-bit scabious, marsh helleborine, lousewort, meadow thistle and marsh valerian
    • an extraordinary number of rarities among the higher and lower plants, snails and insects.
  4. Mesolithic environmental change at Cothill Fen, Oxfordshire
    P. Dark
    Originally published December 2000. Published online May 2023

    Summary...
    Cothill Fen occupies a shallow valley 7 km SW of Oxford, in the parish of St Helen Without (NGR SU 461998). It was one of the first sites in England where peat deposits were investigated using the technique of pollen analysis (Clapham & Clapham 1939), and remains significant for reconstructing long-term vegetational change because suitable pollen-bearing deposits are rare in southern England.
  5. Environmental change at Sydlings Copse, Oxfordshire, c. 8500 BC to the Present
    P. Dark
    Originally published December 2000. Published online May 2023

    Summary...
    Sydlings (or Sidlings) Copse is a small (c. 3 ha) area of woodland occupying a valley 4 km north-east of Oxford, in the parish of Stowood (NGR SP 556096). The site forms part of a Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust nature reserve, and has been actively managed to encourage species diversity. The woodland consists predominantly of ash (Fraxinus excelsior), field maple (Acer campestre), hazel (Corylus avellana) and oak (Quercus robur). It has a rich ground flora with many species designated as ‘ancient woodland indicators’, including wood anemone (Anemone nemorosa), herb Paris (Paris quadrifolia) and toothwort (Lathraea squamaria) (Day 1993).
  6. The Hydrology and Plant Communities of Cothill Fen SSSI
    P. Morris
    Originally published December 2000. Published online May 2023

    Summary...
    1. Cothill Fen Site of Special Scientific Interest (SSSI) contains several compartments including two nature reserves, Cothill National Nature Reserve (NNR) and Parsonage Moor. However, it is a single hydrological unit consisting of an in-filled valley system.
    2. The hydrological relationships of fen ecosystems are outlined, including the importance of catchment geology in determining both the quantity and quality of their water supply.
    3. The Cothill catchment includes leached Upper Corallian Sands, but investigations indicated that the fen’s groundwater supply is derived largely from the Upper Corallian Limestone.
    4. The hydrological integrity of the site is demonstrated by the original valley relief. The present surface generally exhibits a gentle south-easterly slope, modified by the presence of old peat cuts.
    5. The site hydrology was studied to determine water table levels, patterns of water flow, and the roles of streams and groundwater. The results indicate that the peat cuts are important features, and that the principal water supply is groundwater seepage from spring lines.
    6. The fen, fen meadow and dry reed bed plant communities on Parsonage Moor are described. A quantitative study revealed complex patterns between and within these communities, and indicated that the overriding factor is variations in water regime.
    7. Community–water regime relationships are considered in a selected area, within which cluster analysis identified ten community types that are evidently associated with differences in water regime.
    8. The cluster communities are compared with NVC communities. The closest similarities are with black bog rush–blunt-flowered rush (Schoenus nigricans-Juncus subnodulosus) extreme rich fen, M13, purple moor grass–meadow thistle (Molinia caerulea-Cirsium dissectum) fen-meadow, M24, and two sub-communities (M13c & M24a).
    9. Conservation issues are considered. On-site drainage schemes pose a threat, but other activities such as peat cutting have been beneficial. Within-catchment threats include groundwater abstraction and eutrophication. Prevention of natural succession can be partly achieved by scrub clearance but may ultimately require the creation of new peat cuts.
  7. Controls on the Composition of Vegetation of Valley-head Fens in the Oxford region
    B. D. Wheeler
    Originally published December 2000. Published online November 2023

    Summary...
    The environmental conditions associated with the occurrence of two of the main plant communities (M13, black bog-rush – blunt-flowered rush, Schoenus nigricans – Juncus subnodulosus mire and M22 blunt-flowered rush – marsh thistle, Juncus subnodulosus-Cirsium palustre fen meadow) of valley-head fens in the Oxford region are compared, using data from the Oxford region and from eastern England. Both communities occur in similar topographical circumstances and can be associated with comparable water tables and base richness, but examples of M13 are consistently found in less fertile conditions than M22. Low fertility appears to be a consequence of three factors: low phosphate concentrations associated with a P-deficient groundwater supply, immobilisation of P by adsorption upon calcite precipitates and a low fertility substratum (often sands and gravels). M13 vegetation is largely confined to fens fed by chalk or limestone aquifers, and is associated with consistently high summer water tables. M22 vegetation also occurs in fens fed from chalk or limestone, but it is then typically associated with lower summer water tables and with less permeable and more fertile substrata. Valley-head fens in this region that are fed primarily from drift aquifers do not support M13 vegetation but M22 communities occur both in locations with consistently high summer water tables and with lower water levels. The drift-fed permanent seepages that support M22 vegetation are more fertile than comparable chalk or limestone-fed permanent seepages with M13 vegetation. The conjunction of conditions which favour M13 vegetation (strong chalk or limestone springs, permeable and low fertility substrata) is uncommon and probably largely accounts for the localisation and scarcity of this community.
  8. Fens of Oxfordshire: their importance for invertebrates
    K. Porter
    Originally published December 2000. Published online November 2023

    Summary...
    An invertebrate survey of the Oxfordshire fens revealed the unexpected. The number and quality of sites has led to a re-evaluation of the national significance of these small wetlands. One group of insects in particular, the soldierflies, reveals fascinating links to the fens of East Anglia and North Wales.
  9. Conservation of the Southern Damselfly
    G. Steven
    Originally published December 2000. Published online November 2023

    Summary...
    The southern damselfly (Coenagrion mercuriale) is one of the small blue damselflies. It has received special attention as a result of being listed on the Berne Convention on the Conservation of European Wildlife. This convention was enshrined in law by the Habitats and Species Directive (HSD) and the southern damselfly has consequently been included in domestic legislation by adding it to the list of protected species, and in the Biodiversity Action Plan. It was listed in the British Red Data Book before the HSD came into force, together with another eight species (three now extinct), but it is the only one of our rare species to have international status.
  10.   The Terrestrial Mollusca of the Valley-head Fens of Oxfordshire
    S. J. Gregory
    Originally published December 2000. Published online November 2023

    Summary...
    Many aspects of the natural history of Oxfordshire have been well studied in the past and sites within the county of national or even international importance have been recognised. The rich botanical interest of Oxfordshire’s valley-head fens has long been appreciated. In recent decades work by English Nature has shown that the entomological interest, first hinted at by historical records collated in the Victoria County History of Oxfordshire (Salzman 1938), is considerable and of international importance (English Nature 1997). In general non-Insect groups are less well known, but in the last two decades the distribution of terrestrial Mollusca, snails and slugs, across Oxfordshire has been widely researched. This paper highlights some of the findings about the terrestrial Mollusca fauna that inhabit Oxfordshire’s valley-head fens.
  11.   Peat and Tufa Sites in and near Oxfordshire (provisional list)
    A. Parker, C. R. Huxley-Lambrick and J. Simpson
    Originally published December 2000. Published online November 2023