Mire ontogeny, environmental and climate change inferred from fossil beetle successions from Hatfield Moors, eastern England

Results of a fossil Coleoptera (beetle) fauna from a fen edge sequence from Hatfield Moors, Humberhead Levels, are presented. Mire ontogeny inferred from this location and others are discussed, particularly in the light of previous palynological and plant macrofossil investigations. Peat initiation across most of the site centres around 3000 cal BC, characterised by a Calluna-Eriophorum heath with areas of Pinus-Betula woodland. The onset of peat accumulation on the southern margins of the site was delayed until 1520-1390 cal BC and appears to overlap closely with a recurrence surface at a pollen site (HAT 2) studied by Brian Smith (1985, 2002) dated to 1610-1440 cal BC, suggesting that increased surface wetness may have caused mire expansion at this time. The faunas illustrate the transition from eutrophic and mesotrophic fen to ombrotrophic raised mire, although the significance of both Pinus- and Calluna-indicating species through the sequence suggests that heath habitats may have continued to be important. Elsewhere, this earlier phase of rich fen is lacking and mesotrophic mire developed immediately above nutrient poor sands, with ombrotrophic conditions indicated soon after. Correspondence analysis of the faunas provides valuable insights into the importance of sandy heath habitats on Hatfield Moors. The continuing influence of the underlying coversands suggests these may have been instrumental in mire ontogeny. The research highlights the usefulness of using Coleoptera to assess mire ontogeny, fluctuations in site hydrology and vegetation cover, particularly when used in conjunction with other peatland proxies. The significance of a suite of extinct beetle species is discussed with reference to forest history and climate change.

Pinus and Prostomis: a dendrochronological and palaeoentomological study of a study of a mid-Holocene woodland in Eastern England

Tree-ring analysis of sub-fossil Pinus sylvestris L. and Quercus sp. and their associated sub-fossil insect assemblages from tree rot holes have been used to study a prehistoric forest buried in the basal peats at Tyrham Hall Quarry, Hatfield Moors SSSI, in the Humberhead Levels, eastern England. The site provided a rare opportunity to examine the date, composition, age structure and entomological biodiversity of a mid-Holocene Pinus-dominated forest. The combined approaches of dendrochronology and palaeoentomology have enabled a detailed picture of the forest to be reconstructed, within a precise time frame. The Pinus chronology has been precisely dated to 2921- 2445 BC against the English Quercus master curve and represents the first English Pinus chronology to be dendrochronologically dated. A suite of important xylophilous (wood-loving) beetles that are today very rare and four species that no longer live within the British Isles were also recovered, their disappearance associated with the decline in woodland habitats as well as possible climate change. The sub-fossil insects indicate that the characteristic species of the site's modern-day fauna were already in place 4000 years ago. These findings have important implications in terms of maintaining long-term invertebrate biodiversity of mire sites.

Organisational controls, typologies and time scales of paraglacial gravel-dominated coastal systems

The fundamental controls on the initiation and development of gravel-dominated deposits (beaches and barriers) on paraglacial coasts are particle size and shape, sediment supply, storm wave activity (primarily runup), relative sea-level (RSL) change, and terrestrial basement structure (primarily as it affects accommodation space). This paper examines the stochastic basis for barrier organisation as shown by variation in gravel barrier architecture. We recognise punctuated self-organisation of barrier development that is disrupted by short phases of barrier instability. The latter results from positive feedback causing barrier breakdown when sediment supply is exhausted. We examine published typologies for gravel barriers and advocate a consolidated perspective using rate of RSL change and sediment supply. We also consider the temporal variation in controls on barrier development. These are examined in terms of a simple behavioural model (BARCH) for prograding gravel barrier architecture and its sensitivity to such controls. The nature of macroscale (102–103 years) gravel barrier development, including inherited characteristics that influence barrier genesis, as well as forcing from changing RSL, sediment supply, headland control and barrier inertia, is examined in the context of long-surviving barriers along the southern England coastline.