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ForewordThese proceedings are the result of hard work and enthusiasm of many individuals and organisations involved in action and research into the biodiversity and management of Aspen woodlands in the UK. This interest and effort culminated in a one-day conference held at The Duke of Gordon Hotel, Kingussie in the heart of Aspen country on Friday the 25th May 2001. Over 120 people interested in the biodiversity and management of Aspen woodlands attended the conference. The quality of both the presentations and the poster sessions convinced the organisers of the need to publish this material as a fitting permanent record of the conference. Most of the papers in these proceedings were presented in one form or another at the conference, with a small number of additional important papers invited from other contributors. It is hoped that these proceedings have captured the expertise and interest of the various specialists and enthusiasts that was so evident on the 25th May 2001. In particular, it is hoped that these papers will stimulate further positive action and research into the biodiversity and management of Aspen woodlands in the UK. As a focus for future action, Trees for Life have offered to establish and host a web-site and central information resource on Aspen that is easily accessible to land managers, researchers and the general public. If you would like to become more involved in Aspen action please visit Trees for Life's website: www.treesforlife.org.uk/tfl.aspen_info_resource.html Finally, we would like to thank the sponsors and partners; Aberdeenshire Council, Butterfly Conservation, Cairngorms Local Biodiversity Action Plan, Cairngorms Partnership, Forest of Spey Project, Forestry Commission, Highland Council and the Highland Local Biodiversity Action Plan Partnership, RSPB, Scottish Natural Heritage (SNH), and Woodland Trust Scotland, who came together to make this conference happen. We are very grateful to the proceedings authors and photographers who contributed their time and efforts so freely. In particular, special thanks are due to Tom Prescott of the RSPB, and to Anne Elliott and Peter Beattie of SNH for organising such a successful and enjoyable event. OverviewAs a woodland type, or as a significant component of other woodlands, Aspen is restricted, in the Scottish Highlands, to a very limited number of sites mainly in the North-east. Here its local abundance, in parts of Badenoch and Strathspey especially, making a striking contribution to the landscape, seems at odds with its lack of formal recognition in current national vegetation classifications. With one exception, the papers in these proceedings concentrate on Aspen in the North east Highlands, where the conference and field trip were held. Links could and should be made with Scandinavian ecologists, who view Aspen, especially old individual trees, as keystone components in preserving biodiversity in boreal forests. There, Aspen is a focus of current research, e.g. as part of the University of Helsinki's Biodiversity in Boreal Forests project (www.helsinki.fi/science/biobof/). In the Scottish Highlands, Aspen is particularly associated with well drained, often moist, mineral soils. Here it was a very early post-glacial colonist (before Scots pine) and has persisted in mixed woods with Birch, Hazel, Willow and Rowan, which are probably of great antiquity. It also occurs more rarely, as stands within the native pinewoods. As a tree species, Aspen is widespread across the British Isles appearing to be especially frequent in South-east England (Perring and Walters 1962). Examination of a selection of recent county Floras from England which map Aspen at the tetrad scale reveals Aspen to be very frequent in some areas, ranging from just 8% of tetrads in Devon (Ivimey-Cook 1984) to 35% in Kent (Philp 1982) and a remarkable 41% in Sussex (Hall 1980). Do large Aspen stands occur outside the Highlands? The scant descriptions in these Floras make it hard to place Aspen into an ecological context, but the resource seems to be very large elsewhere, warranting more attention. Rare species confined to, or with nationally important populations on Aspen include flies, moths, beetles, fungi, lichens and mosses, as described in subsequent papers. In terms of practical nature conservation, a number of these species are in need of emergency "first aid". The invertebrates, as is so often the case, are in the greatest need of targeted (and monitored) management. They include a number of species with critically low populations which utilise relatively ephemeral components of the total Aspen resource, e.g. the decaying cambial layers under the bark of large diameter logs on the ground, or the foliage of Aspen suckers less than 1m high. A number of lichens and one moss are similarly restricted to just a few individual Aspen trees, though in the medium term they may be able to persist on these trees. In a turn around from usual situations, these proceedings lack information (with one notable exception - European beaver) on the vertebrate fauna associated with Aspen. For example, we appear to know next to nothing about the bird species and communities associated with Aspen in this country. Elsewhere in Europe, Aspen woodland and its dead wood resources attract several species of hole nesting birds, including various species of woodpeckers, some of which are absent from the UK. Aspens are also used by other, perhaps unexpected, species such as Capercaillie (Tetrao urogallus). The 'Bird species of UK Aspen woodlands' paper has yet to be written, but breeding records of Buzzard (Buteo buteo), Great spotted woodpecker (Dendrocopus major) Redstart (Phoenicurus phoenicurus) and Redwing (Turdus iliacus) from the afternoon field trip suggests it is an area worthy of further investigation.
For all of these 'Aspen dependent' species, chance events or uninformed management could be devastating for local populations. All require regular population and distribution monitoring and habitat management trials aimed at securing populations. It is beholden on specialists, advisors and site managers to consider the implications of any proposed actions (or inaction) on other taxonomic groups or habitats. Mellings and Compton report the apparent loss of the BAP weevil, Byctiscus populi, at one site due to the removal (for unspecified conservation reasons) of Aspen scrub. Though statistically unlikely, creation of dead wood to increase potential breeding sites for threatened Diptera could lead to a loss of a similarly threatened lichen or moss. Practically, we either accept that risk (not recommended!) or we ensure that adequate baseline surveys are carried out prior to management, and that site managers know the exact location of important trees. Unfortunately, the current lack of skilled field lichenologists and bryologists is a critical problem for facilitating informed management decisions. Peter Quelch's goal of protecting, regenerating and expanding all existing Aspen woods, stands and trees, as well as planting into new areas deserves support. However, it has to be remembered that it will be decades before some components of the overall Aspen habitat will have increased, e.g. large diameter trees and snags. Clonal variation is almost certainly a significant determining factor for the epiphyte communities of Aspen and quite plausibly for other groups e.g. Diptera. New plantings of Aspens should follow the protocol adopted by Trees for Life (Watson Featherstone, this volume) and include material from as wide a range of locally occurring clones as possible. Much attention has centred on the importance of the largest Aspen stands, as being the only instances whereby natural processes can maintain a continuity of supply of key micro-habitats. Rothero highlights the possible significance of smaller stands and wayside Aspens for bryophytes, and Coppins et al. (2001) have demonstrated the outstanding importance of some small Aspen stands for lichens. Such examples should be targeted for survey and conservation. Given that Aspen will sucker so freely, it is obvious that exclusion or other control of grazing animals will be an important tool to expand existing stands. Complete exclusion of browsers may not be desirable, as the maintenance of successional habitats with associated pollen and nectar sources may be of value to foraging adult invertebrates. Aspen stands occur in a wide variety of contexts and important habitats may occur within the bounds of a projected Aspen expansion zone. Complete exclusion of grazing from such areas may be damaging to other interests. Again, adequate survey prior to formulating management plans is required. Several contributors discussed and highlighted the grants and financial assistance available to land managers to progress practical action for Aspen and its dependent species. Specific examples of the practical work carried out to date are presented, including the challenges of reconnecting isolated Aspen stands to facilitate important ecological processes, such as species dispersal or gene flow. As a number of authors point out, we are only just beginning to identify and understand the complex biodiversity associated with Aspen in the UK, and clearly much is still waiting to be discovered. Finally, Anne Elliott's paper illustrates that interest in Aspen is not just the domain of ecologists and specialist researchers. Aspen has strong cultural links for the people of the Scottish Highlands and their support will be crucial if any action for Aspen is to be successful. We should not lose sight of the fact that Aspen woodlands are a beautiful and striking feature of the Highland landscape, and worthy of conserving for that reason. Indeed it can be argued that Aspen helps improve the quality of life for local residents and helps make the Highland area special for visitors and tourists. Aspen seems to have survived as an ancient remnant up to now largely by default, rather than by design. These proceedings provide compelling evidence of why this situation should change and how Aspen conservation and management should move up the UK conservation agenda in the future. ReferencesCoppins, B., Street, S. and Street, L. 2001. Lichens of Aspen woods in Strathspey. Report to British Lichen Society and SNH. Hall, P.C. 1980. Sussex Plant Atlas. An Atlas of the distribution of wild plants in Sussex. Booth Museum of Natural History. Perring, F.H. and Walters, S.M. 1962. Atlas of the British Flora. 2nd. Edition (1976). EP Publishing. Philp, E.G. 1982. Atlas of the Kent Flora. Kent Field Club. Ivimey-Cook, R.B. 198). Atlas of the Devon Flora. The Devonshire Association. Return to The Biodiversity and Management of Aspen Woodlands For further information about aspen, please go to the Aspen Information Resource
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Published: 3 November 2002 | ||||||
