ORFORD NESS INVERTEBRATES
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ORFORD NESS AND ITS REMARKABLE INVERTEBRATE FAUNA STUART WARRINGTON Introduction Orford Ness is a large and highly significant site for its wildlife and geomorphology. The major feature is the 16 km long shingle spit with a cuspate foreland, jutting into the North Sea. The dynamic processes of shingle erosion and deposition can clearly be seen, and the speed of change can be dramatic (Packham et al. 2001). A specialised and rare vegetated shingle habitat has developed at Orford Ness, with vegetation along the top of shallow ridges where finer sediments hold a little more moisture and organic matter. The ridges nearest the sea have extensive patches of beautiful and scarce Sea Pea Lathyrus japonicus. The older ridges have numerous lichen species amongst the vascular plants. The vegetated shingle habitats are fragile and have been lost where the shingle was disturbed by vehicle movements or trampling (Warrington et al. 2013). Orford Ness also supports an interesting and rare habitat where there is a natural transition from the shingle into a sheltered saltmarsh, which is present all along the eastern edge of Stony Ditch, a tidal creek that runs through the site. Elsewhere the saltmarsh succession is truncated by river wall embankments. On the Alde-Ore river side of the Ness are a series of grazing marshes within the clay river walls. These are not classic freshwater marshes as the only freshwater input is from rainfall and seawater seepage frequently occurs, thus the clay soil has a strong saline content and the ditches and pools vary from almost fresh after heavy rain to hyper-saline after dry, hot weather. Within these marshes, there are also two patches of reed-swamp. The numerous saline and brackish lagoons and pools across Orford Ness, which total over 40 ha, are also of great nature conservation significance, as they support a range of unusual flora and fauna. There are also many, varied ‘brownfield’ habitats on the Ness where human activity has left roads, buildings and other structures, on the shingle and marsh areas, which have been colonised by nature. An overview of the layout of Orford Ness and a summary of the habitats are illustrated in Figure 1 (overleaf). Thus, Orford Ness hosts several unusual and rare habitats and, not surprisingly, it has every UK and European nature conservation designation (Warrington et al. 2013). The majority, but not all, of the site is owned and managed by the National Trust. This article is a review of the terrestrial and aquatic invertebrate fauna currently known at Orford Ness (including lagoon and saltmarsh species but excluding the fully marine species). It investigates the characteristics of this fauna, the habitats and highlights some of the rare and special species. Invertebrate Recording Orford Ness missed out on the Victorian surge in interest in studying and recording natural history, probably due to its remoteness and then the War Office acquired the site and closed it to the public. Fewer than 3% of the 13800 invertebrate records collated for the site are dated prior to the National Trust purchasing most of the site from the Government in 1993. Most of these records come from surveys of the Trans. Suffolk Nat. Soc. 59 (2023)