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Nature Conservancy Council
Birds, bogs and forestry
The peatlands of Caithness and Sutherland
David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald
To view or download the complete publication
visit: http://www.jncc.gov.uk/page-4322H ~ NATURE C()NSERVANCY COUNCIL Birds, bogs and forestry The peatlands of Caithness and Sutherland
David A Stroud, T. M. Reed, M. W. Pienkowski and R. A. Lindsay Edited by D A. Ratcliffe and P H. Oswald
Contents
Summary 5
Introduction .~ LI The peatlands of Caithness and Sutherland: the rise of 1 conservation problems 11 L2 Survey methods 16 The blanket bog 2 2.1 The Peatland Survey of Northern Scotland 17 2.2 The origin of the peatlands in relation to forest history 18 2.3 Peat formation and bog types 19 2.4 The international distribution of blanket 24 2.5 The significance of surface patterning 24 2.6 Threats to and losses of peatlands in the British Isles 28
NCC's Upland Bird Survey in Caithness and Sutherland 3.1 Introduction 31 3 3.2 Programme of ornithological surveys 32 3.3 Composition of the peatland breeding bird fauna 34 3.4 Waders 36 3.5 Otherwaterfowl 40 3.6 Raptors 44 3.7 Other species 46 3.8 Conclusions 50
Overall distribution and numbers of peatland birds in Caithness and Sutherland 4.1 Introduction 4 4.2 Wader densities and habitat characteristics 59 4.3 The identification and mapping of areas of peatland suitable for breeding waders 68 4.4 The use of1andforrns to estimate abundance and losses of waders on peatlands 72 4.5 The numbers of other peatland breeding birds 75 4.6 Summary of the ornithological interest 75
Unsurveyed habitats and species groups 5 5.1 Lochans, lochs and rivers 77 5.2 Invertebrates 77
Effects of afforestation on the ecosystem 6.1 Effects on birds 79 6 6.2 of peatland birds 82 6.3 The lack of compensatory gain in forest birds 83 6.4 Effects on vegetation 85 6.5 Effects on abiotic features 89 6.6 An overall assessment 90
International implications 7.1 The 'Bern' Convention on the Conservation of European Wildlife and 7 Natural Habitats 91 7 .2 The 'Ramsar' Convention on Wetlands ofintemational Importance especially as Waterfowl Habitat 92 7 .3 EEC Directive on the Conservation of Wild Birds 93 7 .4 The World Heritage Convention 94
3 8 Birds and bogs: their conservation needs 95 9 Acknowledgements 109 l References 111 Appendix 11 Methods of ornithological surveys 119
4 Summary
The blanket bogs of Caithness and single area of habitat in the United Sutherland Kingdom that is of major importance on The cool, wet and windy climate of the world scale, because of its global northern Scotland has led to the scarcity. According to evidence from development of extensive tracts of within the peat, the current treeless peatland which cover the landscape of condition over most of the deep peat most of Caithness and Sutherland. This area is not due to historical clearance of is possibly the largest single expanse of natural forests by man. The peat bogs blanket bog in the world and the largest are a natural Post-glacial climax
Blanket bog is now under intense threat, mainly from afforestation. The area of the Caithness and Sutherland peatlands already lost to forestry represents perhaps the most massive single loss ofimportant wildlife habitat since the Second World War
5 vegetation type (section 2.2). They conservation of wetland habitats and represent the largest area of actively bird species (Chapter 7). Many of the growing acid bog in Britain, and their breeding bird species on these vegetation is composed of plant peatlands are listed in Annex 1 of the communities which have no European Economic Community's counterparts elsewhere, except in Directive on the Conservation of Wild Ireland, where very significant losses Birds. Under this Directive Member have already occurred. The high States have entered into an obligation to degree of surface 'patterning' or pool take special steps to protect the habitat formation on the flatter areas of of such species and other migratory peatland ('flows') is of particular birds. The 'Bern' Convention requires conservation significance. The pools conservation of threatened bird support a specialised range of mosses habitats, while the peatlands meet the (especially species of Sphagnum) and agreed criteria of internationally vascular plants, and they provide important wetlands and hence qualify essential feeding habitats for wetland for designation under the 'Ramsar' birds. Convention. The World Heritage These blanket bogs support a Convention requires the conservation of particularly varied northern type of natural features of outstanding bird fauna not found in identical universal value for the heritage of composition elsewhere in the world. mankind. They hold important breeding Of all terrestrial habitats in Britain, populations of golden plover, dunlin, these blanket bogs are the largest greenshank and arctic skua. The lochs example of a primaeval ecosystem. and smaller dubh loch ans support They are of global significance, with breeding red-throated and black both structural and biological features throated divers, greylag geese, wigeon, peculiar to this country. However, their teal, common scoters and red-breasted continued survival is now under threat mergansers. Rare breeding waders include Temminck's stint, ruff, wood The threat sandpiper and red-necked phalarope. Coniferous is destroying Raptors such as hen harrier, golden these peatlands. Both the state forestry eagle, merlin, peregrine and short enterprise and a private sector eared owl also use the bogs as company have obtained extensive land breeding or feeding areas (Chapter 3). holdings on the open market and now Many of these species have their main own or manage extensive areas of distribution in subarctic and arctic Caithness and Sutherland. Whilst two areas, and the peatlands of Caithness decades ago threats to these peatlands and Sutherland have considerable on this scale would have seemed e::;oloqical affinities with the arctic inconceivable, land-use change h:ndrc s (sections 2.5 and 3.3). unprecedented in its speed and scope Con.:iiderable bird populations are is now in progress (section 2.6} The total present (section 4.2 and Table 0.1), area of blanket bog in Caithness and although densities of individual species Sutherland is estimated to have covered are often low. We have estimated that 401,376 ha before afforestation. Since some 4,000 pairs of golden plover, 3,800 then, at least 79 ,350 ha have been pairs of dunlin and 630 pairs of planted or are programmed greenshank breed on these peatlands. planting, about 67,000on peat. They hold considerable proportions of Successful afforestation requires the European Communities' breeding deep-ploughing and draining, which populations of several wader, waterfowl disrupt water-tables and surface flow and raptor species, including 66% of patterns and lead to longer-term greenshank. 35% of dunlin and 17% of erc>s1on. shrinkage, deep cracking and golden plover (Table 8.1). oxidation of peat (Chapter 6). As the The United Kingdom has accepted trees become established, higher international commitments for the evapo-transpiration rates lower the
6 water-table further and change the soil planted. Moorland bird densities thin structure. Ground vegetation is out over a perimeter zone beyond the eliminated when the forest closes into forest edge, and suggestive indications thicket after 10-15 years. that this is partly an effect of increased Afforestation is inimical to the survival predation from crows and foxes are of moorland breeding birds. Whilst under investigation. Evidence for some species may persist within young marked changes in vegetation on plantations for a short period. they unplanted ground adjoining new disappear once the forest canopy plantations already exists and is closes into dense thicket. From this consistent with a surface drying effect. until the mainly unthinned forests Small enclaves of unplanted 'flow' and are clear-felled, the transformed other habitats left unplanted within the habitat excludes all the species of open forests are of doubtful value, especially moorland except the few which may be in the longer term, either as examples to nest in trees, but even these will of peatland vegetation and structure or depend for feeding on the extent of for their bird assemblages. open ground remaining unplanted. The The physical and chemical effects of peatland bird assemblage is replaced coniferous plantations also extend far by one of woodland which, as well as more widely than the plantations being almost entirely different, is of themselves. After ploughing and much lower conservation value draining there are increased sediment because most of its species are so loads in streams and lochs, faster widespread and common. Neither the nm-off. and other alterations to the vegetation nor the bird assemblage hydrology of catchments. During the show more than insignificant recovery early stages of plantation growth there to the previous peatland types during can be short-term eutrophication owing subsequent clearance phases in the to fertiliser application run-off. This forest rotation. can affect nearby acid bogs by Afforestation can cause non-breeding wind-drift and cause profound nutrient and territory desertion by wide-ranging pollution of streams, with growth of algal predatory and scavenging birds, such blooms (section 6.5). All these factors as golden eagle and raven. even when reduce the quality of breeding habitat only part of the open hunting range is for water birds such as dippers and
7 divers as weU as affecting commercial are in direct competition for the same freshwater fisheries, which are of major areas of peat bog. economic importance in Caithness and The results ofNCC's Peatland Survey Sutherland (section 6.1). of Northern Scotland are briefly The impact of afforestation of the summarised (Chapter 2) and will be blanket bogs in Caithness and published in detail elsewhere (Lindsay Sutherland causes a serious net loss of et al. in prep.). nature conservation interest which may extend beyond the areas actually Conservation aims and the futw:e planted. The future of these peatlands is uncertain since afforestation continues The surveys unabated. This report is not concerned The Nature Conservancy Council with the questions that have been raised (NCC) has undertaken extensive survey elsewhere concerning the economic work concerned with both the breeding and social justifications of such upland birds and the vegetation of the forestry (National Audit Office 1986), but peatlands. The methodology of NC C's rather seeks to present the Upland Bird Survey and Moorland Bird conservation case for the protection of Study is presented in the Appendix. the peatlands (Chapter 8). The Royal Society for the Protection of Previous conservation measures Birds (RSPB) has also conducted consisted of identifying exemplary sites surveys of breeding birds, some of to represent the range of interest in the them using this methodology (section peatland ecosystem, with the intention 3.1). Between 1979 and 1986 a sample of of conferring special protection on some 19%1 of moorland in Caithness and these as National Nature Reserves Sutherland was surveyed quantitatively (NNRs) or Sites of Special Scientific for its breeding bird populations. The Interest (SSSis). Not only is this an surveys were used to assess the nature extremely arbitrary approach in the conservation significance of the particular situation, but reassessment in moorland bird populations throughout the light of fuller surveys and the two districts of Caithness and international evaluation has shown it to Sutherland. be quite inadequate in meeting the The principal species of breeding conservation need. The Caithness and waders-golden plover, dunlin and Sutherland peatlands are now greenshank all exhibit a regarded as having a national and considerable range of breeding international importance which lies in densities, which can be related to their total extent, continuity and variations in vegetation and its structure diversity as mire forms and vegetation (Chapter 4). Associations between complexes and in the total size and breeding waders and habitat features species composition of their bird allow the interpolation of results over populations. unsurveyed areas, using map evidence Forestry interests regard all alone. This method has been tested, plantable land outside specially and the results used to obtain protected areas as potentially available population estimates (Table 0.1). By for afforestation and have already examining map evidence from areas planted up to the precise boundary of that have been afforested it is possible some SSSis. Most of the remaining to estimate the numbers of the main peatland area is plantable, and under wader species previously occupying present government policy and them and thus the loss of populations financial rules there is little to prevent through afforestation. There have been the whole of this becoming afforested, losses of up to 19% of golden plover, outside the present limited area of SSSis dunlin and greenshank (section 6.2). A and NNRs. The nature conservation disproportionate amount of prime case is that the losses of habitat and habitat for waders has been ploughed birds already sustained on these and planted: foresters and these birds internationally important peatlands are
8 so heavy that any further afforestation is also revealed the and continuing unjustifiable. These losses are losses caused by Already, compounded by the parallel losses to habitat supporting nearly 19% of the moorland habitats (including blanket three principal breeding waders has bog) and birds which continue apace been destroyed or programmed for through further afforestation in other planting, and only eight of 41 parts ofBritain and abroad. hydrological systems in Caithness and Maintenance of nature conservation eastern Sutherland have been left free interest could be achieved simply by from afforestation. The area lost to retaining the existing pattern of forestry - most of it since the passing of land-use. Such an approach is the Wildlife and Countryside Act 1981 compatible with existing agricultural - represents perhaps the most massive and sporting interests. Indeed, an single loss of important wildlife habitat integrated conservation policy for these in Britain since the Second World War. areas could be of advantage to these Decisions to promote appropriate other land-use interests. conservation measures are needed NCC's surveys enable the extent of the promptly if the losses already sustained nature conservation interest of these are not to increase. peat bogs to be quantified, but they have
9 TableO.l Estimated proportions of national and European Cormnunities' populations of selected bird species breeding in the Caithness and Sutherland peatlands
·~r:; r;;!I ~g r;; :~ '1J f:Ji q;·S"' .If 'Jl.!f' J:il-Q;,; lf,S Red-throated diver 1,000-1,200 !4% 14% Gomersall, Morton& Wynde(l984)
Black-throated diver* 30 ISO 20% 20% Campbell & Talbot (!987)
Greylag goose c.300 600.800 43% Owen, Atkinson-Willes & Salmon (1986) Sharrock (1976)
Wigeon BO 300-500 20% 20% Sharrock (1976)
Common seater 30+ 75-80 39% 16% Thom(l986) RSPB and NCC (unpublished data)
Henhan:ier* 30 600 5% 1% Newton(l984)
Golden eagle* Dennis el al. 0984) Watson, Lang slow & Rae (1987)
Merlin* Bibby & Nattrass (1986)
Peregrine* Ratcliffe (1984)
Golden plover* Piersma (1986); this report
Temminck's stint• Dunlin 3,830 9,900 39% 35% Piersma (1986); this report Ruff*• Greens hank 630 960 Piersma (!986); this report Wood sandpiper*• Red·necked phalarope*• <10 19-24 Rare Breeding Birds Panel (1986) Arctic skua 60+ 2,800+ Furness(l986) Short-eared owl* 50 l,000+ Sharrock (1976) * This indicates species listed on Annex I ofthe European Economic Community's Directive on the Conservation of Wild Birds (79/ 409) as requiring special protection measures, particularly as regards their habitat under Article 4(1). Other listed species are migratory and require similar habitat protection measures under Article 4(2). l This excludes the whole oflreland. 2 EC population uncertain owing to unknown proportion of feral birds in other populations. The population in north-west Scotland is the only one thought to be natural, owing to separation from others. 3 Most of the EC population is of the south European race homeyeri: Britain holds all of the EC population of the nominate race, 6% of which occur on the Caithnessand Sutherland peatlands. 4 The total Caithness and Sutherland population has increased to c. 60 pairs since the 1981 survey (Dennis pers. comm.), but no corresponding national total is available. 5 Most of the EC population consists oft he Mediterranean race brookei; Caithness and Sutherland peallands hold 5% of the EC population of the nominate race. 6 For reasons of confidentiality it is not possible to indicate precise numbers and distributions of these species breeding in Sutherland and Caithness. The Scottish populations ofTemminck'sstintand red-necked phalarope are the only representatives of these species breeding within the EC. Wood sandpipers breed in one other region of the EC but the Scottish population is important in EC terms. 7 DataforallspecieswerealsotakenfromCramp&Simmons(l977, 1980, 1983, !985). 10 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H Introduction l .1 The peatlands of Caithness and where cool, wet climatic conditions Sutherland: the rise of have favoured waterlogging of the conservation problems ground and accumulation of plant Mountains and moorlands are the most remains as peat. It is a formation extensive natural and semi-natural especially associated with flat or gently terrestrial habitats remaining in Britain, sloping ground, but occurs at covering at least one quarter of the increasingly low elevations and on country (about 6-7,000,000 ha), mainly in increasing inclines as climate becomes the west and north. Their vegetation more oceanic towards the north and consists of grassland, dwarf shrub west of mainland Scotland and its heath, peat bog and marsh, alpine islands. Blanket bog covers the high 'meadow', moss and lichen heath, and plateau of Dartmoor, but in extreme fell-field. The local pattern in upland oceanic areas such as Sutherland, vegetation depends on topography, Caithness, Lewis and Shetland and the especially steepness and range of west of Ireland it is extensive on altitude, on the nature of the underlying low-lying moorland down almost to sea rock and derived soils, and on land-use. level. In these situations it represents a Superimposed upon these local northern tundra-like ecosystem which variations are broad geographical has developed in these more southerly trends reflecting the main gradients of latitudes because of the highly Atlantic climate, of decreasing temperature climate. from south to north, and of increasing The largest expanse of blanket bog in oceanicity (particularly increasing Europe, and possibly the largest single rainfall, atmospheric humidity and area in the world (Figure 1.1), is where windspeed) from east to west and the low, rolling moorlands of east towards coasts. Sutherland descend gradually into the Blanket bog, the particular subject of plains of Caithness. Further west in this report, has developed naturally Sutherland, blanket bog is still Figure 1.1 World distribution of blanket bog on Peters' projection, which shows correctly proportioned land areas. The dark areas show those regions within which blanket bog occurs: the total extent of blanket bog is smaller. Note that blanket bog occurs almost exclusively between 40° and 60° latitude north and south on ocean seaboards ~ --~-.. widespread but becomes more relatively undisturbed, and grazing by dissected by higher mountain ranges. large herbivores has been light The whole area of the Caithness and because of the naturally low carrying Sutherland blanket bogs, lying capacify. This is, indeed, a region which between 10 and 450m and originally has largely escaped the more intensive covering 401,375 ha (Figure 1.2), is modem kinds of land-use which have considered in this report. This area affected so many mountain and extends well beyond the largest single moorland areas elsewhere in Britain - expanse of bog, sometimes called 'the upland farming and pasture flow country', occupying much of the improvement, water and hydro-electric area east of a line from Tongue to Lairg supply, mineral extraction, military (Figure 1.3) or an even more restricted training, and the heavier kinds of area (Royal Society for the Protection of recreational use. Its nature Birds 1985). conservation interest has survived 'Flows' are flat or almost flat areas of under a combination of traditional deep bog which are especially management for low-intensity extensive in this region and have in sheep-farming, sporting interest in red many places developed intricate deer, red grouse, salmon and trout, and surface patterns, in the form of complex local small-scale peat-cutting. pool systems. These patterned flows Concern over nature conservation on show wide in the the Caithness and Sutherland and configuration of the pools and peatlands has increased in parallel with intervening ridges or hummocks, and the rapid advance of commercial they are of great scientific interest for afforestation in the region during the their hydromorphology (Lindsay, Riggall last decade. After a long period of & Burd 1985). Associated with this forestry expansion elsewhere in structural diversity is a distinctive and uplands, during which there was little varied set of plant communities with interest in the planting of deep, wet dynamic successional relationships bogs, a combination of silvicultural and and composed of a flora which includes technological advance has quite species of different biogeographical rapidly transformed the situation. Both affinities. There are also numerous state and private afforestation have lochs, of widely varying size, and spread rapidly, benefiting from a moorland stream and river systems. combination of advantageous grant-aid, Within the accompanying fauna, the tax concessions and land-market breeding birds are of outstanding factors. A significant proportion of the interest: they represent a particularly peatland area is now owned by forestry varied 'tundra' type of assemblage and interests, if not actually planted (Figure include nationally and internationally 1.4). Because much of the peatland area important populations of various is at a low elevation, a large proportion species, as well as several national of the total area is potentially plantable rarities. and therefore at risk Afforestation The structural, vegetational and causes a transformation of the peatland f aunal variety are all closely ecosystem and is regarded as almost interrelated, and survey information totally destructive to its nature will be presented to identify and conservation interest (Nature evaluate their interest One of the most Conservancy Council 1986). The notable features is that the wet flow replacement of these unique habitats ground represents an unusually large by an extremely widespread and also area of natural habitat in this country, artificial type of forest ecosystem is where so much of the land has been regarded by nature conservationists as profoundly modified by past human a very substantial net loss of wildlife activity. Although moor-burning has and environmental value. affected much of the total peatland area The novelty, pace and scale of to some degree, quite large areas of the afforestation of the Caithness and wettest ground have remained Sutherland peatlands took conservation 12 Figure 1.2 Distribution of blanket bog in Key Caithness and Sutherland before afforestation. IIBfJ Blanket bog The map of peatland is derived from the soil categories of the Macaulay Institute for Soil Research. All of soil types 3, 4, 4d and 4e were included, with some combina tionsof other categories where the slope has allowed peat formation. From Lindsay el al. (in prep.) 13 Figure 1.3 Callhness and Sutherland, Key showing localities mentioned in the text Moine Thrust I Loc.l{Eriboll Loch (\ Scarmclate / L oc h ""iJ • 0 Calder HalV , 1 ~och \b Loch ,1r' '-V Watien )~Beo Shurrery A Loch Foinaver/#~~ t~pe 8 ~cl 4 / 5' [} en Loyal .';f' Loch Loyal Loch Druim A Loch /)More Scoune ;'Arkle :::,-:.- 1an c:i, a'Chliabhain Slehll o Ben~C\ ·"' n • Hill • Stack "'Loth Stack c5f Dherue .,,u Forsmard Ben Achavanich A ~ Loch Mead1e Loch Nav~ Loch fi C Ali sky A • tr>L9cl}f Ben HeeAhnaharr!c::;:.r Rimsd~e{J~ Loch Mop ~ A A Badanloch llemn ~ 14 Figure 1.4 Distribution of forestry m Key Caithness and Sutherland in relation to the b !anket bog shown in Figure 1.2. Blanket bog Areas shown are either in Forestry Plantations Commission ownership or have Forestry "\:J Grant Scheme approval or are dedicated private woodlands. Map as at January 1986, since when there have been many further FGS applications. 15 interests somewhat by surprise. difficulties of counting birds over such a Incomplete surveys were undertaken wide expanse of peatland meant by the former Nature Conservancy that it has not been possible for NCC to during the late 1960s to identify a series survey all areas of the Caithness and of areas meriting protection as National Sutherland peatlands for their Nature Reserves (Ratcliffe 1977b). ornithological interest. The approach Subsequently, the portents for land-use taken has been that of sampling developments in various parts of Britain representative sites throughout both indicated that priorities for allocation of districts. Thus, this report: scarce survey resources should lie in o briefly draws upon the results of other areas, with emphasis on different NCC's Peatland Survey (the full impacts. The launching of more results of which will be published comprehensive vegetational and elsewhere) in order to relate the ornithological surveys of the Caithness ornithological surveys to concurrent and Sutherland peatlands during studies of peatland vegetation and 1979/80 has been overtaken by the structure and to provide a habitat rapid spread of afforestation, requiring context for the bird fauna (Chapter 2); that the conservation case be o outlines the methods of data presented quickly, albeit from collection by the Upland Bird incomplete evidence. The uplands are Survey (UBS) in ·1979-1988, and later the last great area of undeveloped the Moorland Bird Study (MBS), to natural and semi-natural habitat in gather information on the Britain, these northern peatlands ornithological of the are outstandingly valuable but peatlands (Chapter 3); especially vulnerable. This report aims o develops and assesses methods of to present the case for regarding the interpolating the results of the survey Caithness and Sutherland peatlands as to the rest of the area, using both a national and an international correlations between breeding scientific and cultural resource. densities of waders and features of physical structure and vegetation of Survey methods peatland, whereby the relative 1.2 Since 1980 NCC has undertaken importance of sites for waders can be botanical surveys of the peat bogs identified both from maps and on the within both administrative districts ground without the necessity for a full the Peatland Survey of Northern field survey {Chapter 4); Scotland. This has concentrated o assesses the former and current particularly on identifying and studying extent of peatlands and the degree to the patterned flows from large-scale which bird populations in Caithness maps and aerial photographs. The sites and Sutherland have already been thus identified have subsequently been reduced by commercial afforestation examined in detail on the ground. Such and then estimates potential future a programme of survey is inevitably losses (sections 4. 4 and 6.2); time-consuming because of the nature o summarises the of of the terrain and the remoteness of afforestation on the physical and many sites, and it is only now nearing biological components of the completion (Chapter 2). Virtually all peatland ecosystem (Chapter 6); pool systems have been o assesses the international examined in detail, and about 90% of importance of the peatlands the total area has been assessed at least according to the requirements of the in outline. UK's treaty arrangements (Chapter 7); Complementing this survey, a series o evaluates the overall biological of ornithological sampling surveys have importance of the peatlands, using also been undertaken by NCC since information gained from both of the 1979 - the Upland Bird Survey, bird surveys, the Peatland Survey and continuing from 1986 as the Moorland other sources, and synthesises the Bird Study (Chapter 3). The practical total conservation case (Chapter 8). 16 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H The blanket bog The following account of the blanket high water-table were also found to bog formation is based mainly on display a range of natural Lindsay et al. (in prep.) and included microtopographical elements to provide an essential context for characteristic of undamaged bogs such subsequent chapters. as spongy ridges, hollows, pools and Sphagnum 'lawns'. Detailed The Peatland Survey of Northern descriptions of the peatland flora were 2.i Scotland made at each site and these were During the last seven years, most of the complemented by quantitative peatlands of the north of Scotland have information on species composition been systematically surveyed. In order within 0 · 5m quadrats. Such data enable to identify important areas of peatland, the plant communities of these northern aerial photographs and 1:25,000 maps bogs to be evaluated within a national of Caithness and Sutherland were context. examined. A wide range of these sites There are problems of definition over was then visited to assess the present the limits of peatland as a substrate and condition of those remaining free from as a vegetation category, since within a forestry or intensive drainage. A full peatland landscape there is usually a evaluation was made of their physical gradual transition from deeper peat and hydrological structure and with mire communities to mineral soils floristics. In particular, records were with shallow surface humus, supporting made of any damage to the site by drier grassiand or dwarf shrub heath. drainage or previous severe burning. A An accepted though arbitrary definition high, unmodified water-table was according to substrate is a minimum considered to be a useful indicator of depth of 30cm of organic deposit high conservation value. Sites with a (Clymo 1983). This is the basis for the Table 2.1 Plant communities of the Caithness and Sutherland blanket bogs These were classified by McVean & Ratcliffe (1962) under the following main categories (with their table and list numbers in brackets). Ombragenous mire 0.1 Trichophoreto-Eriophoretum (Table 49, lists 1-12) 0.2 (I'able50) 0.3 (Table 52, lists H2) 0.4 Molinieto-Callunetum (Table 52. lists 13-21) Types OJ, 0.2 and 0.3 have both Racomitrium-rich and lichen-rich fades, while OJ and 0.2 also have dwarf-shrub-rich facies. Separate pool communities of1Wenyanlhes trifoliata and Eriophorum angustifolium, with or without Sphagnum species, occur, mainly in pool systems with Type O.L Soligenous mire S.l Trichophoreto-Eriophoretum caricelosu m (Table 49, lists 13-2!) S.2 Molinia-Myrica nodum (Table53) S.3 Sphagneto·Juncetum effusi (Table 54. lists l-9) S.4 Sphagneto-Caricetumsub-alpinum (Table55, lists l-9) Types O.l-0.4 are readily ri:>r·nm11c:i::•n and extensive: they are the principal means of defining the limits of the pealland resource. Types are common within the ombrogenous mire expanses but cover a much smaller total area. The National Vegetation Classification being compiled at the University of Lancaster by Dr]. Rodwell for NCC has further refined this classification, but it is not yet fully available. 17 distribution of the main peatland areas widely varying radio-carbon age, occur of the map in Figure 1.2, though there at different levels in blanket bog peat in are numerous other patches too small different localities. However, pine and fragmented to be shown at this stumps in the north-west Highlands scale. mostly date to 2,000-2,500 BC. and their Full details of the methods and results occurrence beneath a deep layer of of the Peatland Survey are to be ornbrogenous peat is consistent with published by Lindsay et al. (in prep.). renewal of active bog growth as a result Their report will show the range of bog of increased climatic wetness marking types and peatland vegetation across the onset of the Sub-atlantic period Caithness and Sutherland. In the (Birks 1975). This climatic period, which interim, however, the main plant has prevailed since about 500 BC, is not communities found in these peatlands only wet, but its summer mean are listed in Table 2.1. temperature is also believed to be cooler by 2 °C than that of the Atlantic The origin of the peatlands in period (Godwin 1975). This has 2.2 :relation to forest history a descent of the tree-line by perhaps Many ornbrotrophic bog systems first 200m and given optimum conditions for became established when the wetter l::::H<~vv.,,:u growth of blanket bog. Under conditions of the Atlantic period regime, it is clear followed the drier Boreal period, that trees would naturally be absent around 5,500 BC, though some of the from much if not all of the deeper shallower upland blanket bogs did not blanket bog surfaces in Caithness and begin to form until later. Many bogs Sutherland and that blanket bog show a layer of tree stumps and fallen represents a natural climatic climax logs within the basal peat, suggesting type (Tansley 1939; Godwin 1975; that forest was often overwhelmed by Moore 1987). the rapid growth of bog-mosses During the Sub-atlantic period, the (Sphagnum species). However, the natural tree-line in Caithness and frequent occurrence of a charcoal layer Sutherland has probably been at at the base of the peat has led some around 300m in favourable situations ecologists to infer that human activity where woodland cover has been able first destroyed the forest and that the to develop. It disappears altogether on resulting increase in soil acidification the most exposed coasts, where was as much responsible for the growth montane heaths with species such as of Sphagnum as the direct effect of Dryas octopetala occur almost down to wetter climate. Perhaps both factors sea level. Before human impact began acted in combination. There is good to remove it, woodland probably had a evidence from pollen analysis that patchy cover over the region, mainly on some parts of northern Scotland, such the drier and more fertile mineral soils as the interior of Caithness, Orkney and away from the peatlands, in the glens Shetland, never carried significant tree and on lower hillsides. Scattered cover during the whole of the remnants indicate that it was mainly Post-glacial period (Peglar 1979; Moar birchwood (Betula pubescens subsp. 1969; Johansen 1975; see also Birks odorata) of a subarctic type, with 1984). variable amounts of hazel, willow, It has been supposed that the spread rowan, alder and holly locally. of trees onto blanket bog surfaces Pinewood probably occurred locally in represented periods of return to drier Sutherland, where widespread remains climate (notably during the Sub-boreal in the peat show that Scots pine was period from 3,000 to 500 BC), causing a certainly present locally during the desiccation of the surface and loss of Post-glacial period (Crampton 1911; Sphagnum and other moisture-loving Birks 1975). The native trees in most vegetation. Scottish forest history is places are of small size, as are the confused by the fact that tree remains, remains buried in the peat notably of Scots pine Pin us sylvestris, of 18 2.3 Peat formation and bog types particularly by Sphagnum (Tansley 1939; The recent history of bog development Thompsonl987; Lindsay 1987; Moore 1987). and the present state of the living Sphagnum is a delicate plant which is surface of vegetation reflect recent easily damaged by burning, draining and contemporary environmental or even trampling. Nevertheless, almost conditions, especially of climate. half the 30 species of Sphagnum which For nearly the last 3,000 years Britain occur in Britain are capable, under the and Ireland have been subject to a right conditions, of producing a climate which is both cool and moist, continuous ground layer of vegetation. derived from the North Atlantic The plant is also remarkable in its Westerlies, which steadily gather ability to absorb water, enabling it to mo1sture during their 4,000km crossing maintain the ground surface in a of the northern ocean. On passing over constantly waterlogged, relatively the first land-masses in their tracks they anaerobic state. Without oxygen, the produce measurable precipitation as normal process of decomposition often as two days in every three over the becomes inhibited and, as a result, most oceanic parts of the British Isles. Sphagnum and other plant remains fail Such conditions, combined with a to decompose when they die, but prevalence of rugged terrain, high accumulate over the soil surface as peat winds, low summer temperatures and instead. The major source of water and nutrient-poverty resulting from hard, plant nutrients in such mires eventually acidic rocks, severely limit the potential changes from ground-water to for agriculture and forestry in north atmospheric fall-out because the western Britain, tending instead to thickness of accumulated peat insulates encourage the development of a the living vegetation from the mineral vegetation dominated by plants ground beneath. These are adapted to humid and acidic ombrotrophic ( = rain-generated) mires, conditions, and on flatter ground or true bogs, which contrast strongly The surface of highly blanket bogs shows a bewildering display of pools of different sizes and shapes, illustrating thet tundra-like appearance of these wetlands. Badanloch Bog, Sutherland, August !986 19 with the conditions of fen-peat burning or drainage. formation, where sedges, 'brown' The extreme wetness of the climate mosses, herbs and reeds are dominant ensures that waterlogging occurs under the influence of base-rich almost irrespective of the underlying ground-water (Tansley 1939). The lack geology. This is considered to be the of decomposition in peat systems ultimate development of an means that macrofossil remains and ombrotrophic mire system, resulting in pollen grains locked in the stratigraphic the gradual increment of a completely profile of the deep peat deposits have organic terrain. In this way upland been of enormous value to Quaternary areas with predominantly gentle relief ecologists in revealing the ancient in northern and western parts of Britain, vegetational history of the British Isles from Dartmoor to Shetland, have, over (Godwin 1976). the last 2,000-7 ,000 years, become In lowland areas of England and covered in a smothering mantle of peat Wales, isolated ombrotrophic peat commonly known as 'blanket bog'. The deposits have developed as 'raised main expanses are in Wales, the mires' in places where topography Pennines, the Cheviots, the Southern originally caused the ground Scottish Uplands, the Scottish water-table to remain consistently high. Highlands, the Isle of Lewis and These are formed where lakes Shetland (Figure 2.3). and shallow basins have accumulated Although such blanket bog sufficient organic material to create a landscapes are widespread in western dome of peat (from which they derive Britain and Ireland, their most extreme their name) rising some 4-5m above the and extensive development is in surrounding land. The properties of the northern Scotland. Here, to the east of peat maintain the in a state of the Moine Thrust (Figure 1.3), which almost constant saturation throughout runs from Loch Eriboll to the Sound of the year (Ingram 1982). Sleat, the vast low-lying moorland which In western and upland Britain, where makes up eastern Sutherland and rainfall exceeds 170 'wet days' a year Caithness represents the greatest (Figure 2.1) and average water balance continuous area of blanket bog in gives a consistent surplus of Europe and has been described as precipitation over evapo-transpiration unique in world terms by international between April and September (Figure peatland experts (International Mire 2.2), peat develops also on plateaux and Conservation Group 1986). gentle inclines. Under extreme The distribution and extent of wetness, of more than 220 'wet days' a peatland are affected by the landforms year, shallow peat occurs on slopes of of the underlying geology of the area. up to 20 or even steeper on north-facing Most of the Caithness flows have slopes, The deepest and wettest areas developed on Old Red Sandstone. of peat, dominated by common Further west, around Strathnaver, the cottongrass Eriophorum angustifolium bedrock of ancient Moine schists and and a wide range of Sphagnum orn::ns1:>es becomes harder and less species, tend to form on gentle slopes uniform in structure. West of the Moine and level ground, whereas on steeper Thrust peat development is gradients peat is thinner and is discontinuous (Figure 1.2). Here, the characterised by bryophyte-rich dwarf ancient Lewisian Gneiss, Torridonian shrub heath or acid grassland swards. Sandstone and Cambrian Quartzite These communities of shallower peat form a range of mountains running from are often referred to as wet grass Foinaven and Arkle in the north to Ben heaths. The climate of these regions is More Assynt in the south. In the so wet that peaty soils with moist heaths extreme west and to the south, the are extensive even on steeper and underlying Lewisian Gneiss has been stonier ground. Vegetation character exposed and severely glacially istic of drier ground can however occur scoured (Gordon 1981). There is a on deep peat which has suffered from characteristic terrain of irregular low 20 Figure 2.1 The distribution of 'wet days' across Britain. A 'wet day' is a period of24 hours within which there is precipitation of at least Imm. It is a better index of ecological wetness of climate than total rainfall. Compiled by Ratcliffe (1968) from data published in British Rainfall (1951-1960) ( ...... (\ ) ~;·~~···<•.:) I - 160 140 21 Figure 2.2 West·east gradients of oceanicity across Britain. This index of climatic wetness is the difference between precipitation and evapo-transpiration for the six summer months April to September. Redrawn from Forestry Commission (1957) Surplus more than 20cm Surplus less than 20cm Deficiency less than lOcm more than IOcm 22 Figure 2.3 Distribution of substantial blanket bogs in Britain (indicated by the dark areas). Note that this distribution may differ in detail from that shown on maps drawn to a larger scale 23 moorland, with knobbly bosses of The significance of surface projecting bedrock, stony moraines 2.s patterning with wet heath, and dissected but well Bog surfaces are a product of organic developed blanket and valley bog in growth largely involving a range of the intervening hollows, terraces and Sphagnum species, which have a flats. variety of growth forms and are adapted to different degrees of ground The international distribution of wetness. A bog surface with 2.4 blanket bog undulations which produce a varying Globally, blanket bog is an extremely water-table therefore tends to display a rare habitat. restricted to the few areas range of small-scale patterns resulting where cool oceanic conditions prevail from various growth forms in a (Gore 1983). It is found in Europe in mosaic of Sphagnum. The 'hummock western Norway, the Pyrenees, Great hollow' pattern often referred to when Britain, western Ireland and Iceland, describing bog systems is in fact only a though in this last country much of the small part of the full variation displayed blanket bog is modified by wind-blown by bog surface features. In northern volcanic soil to produce a rich, fen-like Britain the 'hollows' are more likely to vegetation (Einarsson 1968; Goodwillie be water-filled pools, while 'hummocks' 1980). Elsewhere (see Figure l.l), it is may vary from high moss hummocks to recprded from only relatively small low, soft ridges. Lindsay, Rig gall & Burd areas in Labrador, Alaska, Kamchatka, (1985) have suggested that the the Falkland Islands and Tierra del distribution of these features Fu ego, together with small pockets in and their nature are partly New Zealand and the Ruwenzori by climate and partly by slope. They Mountains in Central Africa (Gore suggest that climate determines the 1983). maximum range of surface features for The total global resource of blanket a given area, while the arrangement of bog is estimated to be little more than these on any particular mire depends 10,000,000 ha, of which Great Britain on surface gradient, as postulated by had between one-tenth and one Goode (1973). seventh (see Figure 2.3), though large Although the flat or gently sloping areas have now been lost to forestry. ground and the high humidity and The Republic oflreland has only rainfall (Figure 2.1) produce blanket 771,800 ha of blanket bog, compared bog in Caithness and Sutherland which with Great Britain's 1,000,000 ha, and has is largely of an intensely patterned lost an even larger proportion of its bogs type, considerable variation still exists through commercial peat extraction, within the mire systems of these afforestation and reclamation. Many of northern districts. This variation is the most important individual areas of derived partly from the different local Irish blanket bog have already been patterns of topography and water destroyed (Reynolds 1984; Ryan & movement (Pearsall 1956; Boatman & Cross 1984; van Eck et al. 1984; Bellamy Armstrong 1968) and partly from the 1986). Norway, although appearing to broader regional trends resulting from have widespread blanket bog (Figure altitudinal and climatic variation. Of these 1.1), does not possess large continuous broader trends, the most important are tracts. Most of the country is so rugged the west-east variation corresponding to and steep that blanket bogs tend to be an oceanic-continental climatic scattered in small pockets through the gradient (Figure 2.2) and the south-north ianasc:ape, rather than being the variation relating to the altitudinal drop dominant landform. Thus the United from the southern hill ground to the Kingdom contains a greater total area of more northerly low-lying Ilows, blanket bog than any other country in The general range of patterns found Europe. by Lindsay, Riggall & Burd (1985) across Great Britain as a whole can be seen in Figure 2.4. Within these patterns the 24 Figure 2.4 Distribution and surface structure oft he pool patterns on some British bogs. Within each bo.'C (drawn at a scale of l: 1,000), pools and hollows are shown dark, ridges and hummocks The adjoining numbers indicate average 'rain days' per year for each taken from The Atlas ofBritain and Northern Ireland (published by Oxford University Press in 1963). From Lindsay, Riggall & Burd (1965) 255 a . -~' 200 220 221 . "' " ~ . 188 t. \ t ~ : • •• ..J; : .. ' .~ . ~ .. .. ' ; • ,. .. t : 4' ~, • 1 ... . - t • -. # \ - ~ ' 197 25 surface undulations are so small and constant rainfall onto what is a naturally the water-table fluctuations so limited sloping bog type ensures a steady rate that the major environmental gradients of water seepage through the surface produce a series of narrow zones each layers almost throughout the year. Thus determined by its vertical location in many valleyside flows, though generally relation to the average position of the classed as rain-fed blanket bog, water-table. Each zone (with a vertical support vegetation types which are span of no more than lOcm) supports more closely related to wet heath or own characteristic plant communities. even valley mire in southern Britain and which rely on the stability of the as Fenno-Scandia. Valleyside flows in the a hydrological system for their west are often characterised by an continued survival. Lindsay, Riggall & abundance of Molima caerulea, Myrica Bignal (1983) and Lindsay, Riggall & gale, Narthecium ossifragum, Drosera Burd (1985) have described a range of intennedia and occasionally Sphagnum such zones for Britain. These zones are pulchrum all species well known important not just for their botanical from, for example, the Dorset heaths. features, but also in providing niches for The abundance of Racomitrium the bog invertebrate fauna which, in Januginosum as a component of turn, plays a major role in determining hummock vegetation increases feeding sites for birds. markedly westwards. Drosera The range of physical patterns and intermedia, Carex limosa, Schoenus their associated vegetation zones nigricans, Rhynchospora alba and provides a significant amount of Atlantic bryophytes (e.g. Campylopus variation between bog systems a trovirens and Pleurozia purpurea) also throughout Britain. Sites which have increase in occurrence in a westerly largely similar species lists can still direction. display many differences in the In contrast, eastwards across the two arrangement of their patterns and districts the vegetation reflects vegetation zones. Curtis & Bignal (1985) continental influences, particularly in have investigated the physiognomy of the dominance of a mixed dwarf shrub peatland vegetation and shown how this layer. Such a vegetation structure shows varies within and between peatland some affinities with the bogs of sites. Vegetation structure is affected by Fenno-Scandia, but certain peculiarities physical patterning because make the Scottish type quite distinct. hydro morphological differences result Whilst in Fenno-Scandia the range of in gradients of species abundance, dwarf shrub species typically includes plant growth and thus structure. Chamaedaphne calyculala, Ledum The floristics of the blanket bogs in palustre, Vaccinium vitis-idaea, Caithness and Sutherland are V. uliginosum, Betula nana and Calluna important not only as the extreme vulgaris, in Caithness the list is shorter expression of oceanic influence, with Calluna vulgaris and Erica tetralix compared with mire systems forming the major part of the shrub elsewhere in Britain, but also for the layer. Chamaedaphne and Led um do variations which occur within the not occur naturally in Britain, whilst region. The most pronounced trends Vaccinium vitis-idaea and V uliginosum across the two districts in both are restricted to steep slopes. patterning and vegetation are from east Surprisingly, Betula nana, perhaps one to west. The increased level and of the most characteristic dwarf shrubs frequency of precipitation towards the of Fenno-Scandia, is not found at its most west results a gradual shift abundant in eastern Caithness, but vegetation which clearly displays instead appears to favour a central rain-fed (ombrotrophic) or bog position, occurring on high ridges or characteristics to mires which begin to hummocks in undamaged mires or take on the character of Fenno more generally distributed on Scandian 'sloping fen'. This damaged bogs. Perhaps the most development occurs because the peculiar feature of the dwarf shrub 26 Top left: Common cottongrassEriophorum angustifolium Top right: Oblong-leaved sundew Drosera intermedia Centre left: Bog asphodel Narthecium ossifragum Bottom right: White beak-sedge Rhynchospora alba Bottom left: One ofthe bog-mosses Sphagnum·recurvum 27 layer is Arctostaphylos uva-ursi. Altogether, in the total extent of Generally described as indicative in blanket bog, the diversity and British mires of continental influences, it uniqueness of the patterned flows and is not a mire plant at all in the naturalness of many areas, the Fenno-Scandia, but a woodland Caithness and Sutherland blanket bogs species. Similarly, Arctostaphylos represent one of the most distinctive alpinusgrows as a calcifuge bog and localised of European ecosystems. species in Britain, but on the Continent it To the best of our knowledge. there is is known as a plant of dry habitats, and no other area quite like this anywhere in in the Alps it is a strict calcicole. the world. It is more peculiarly British Lichens of thereindeer-moss type than almost any other vegetation (Cladonia species) also increase complex, except perhaps certain eastwards, though there are also localised bryophyte communities of the western outliers oflichen-rich bog in western mountains and some types of coastal situations. These northern mires anthropogenic grassland and heath. are important for their populations of The area of greatest similarity, the Bog nationally scarce species such as Carex of Erris in County Mayo, has been so limosa, Betula nana, Arctostaphylos degraded by extensive commercial alpinus, 1/accinium microcazpum and peat-working that it is no longer the bog-mosses Sphagnum imbricatum, comparable in nature conservation S. fuscum and S. pulchrum. Blanket bog importance (Bellamy 1986). plant communities are, however, The range of surface patterns in intrinsically species-poor, and their Caithness and Sutherland and the botanical interest lies mainly in the botanical variety displayed by zones combinations of species in dynamic within these patterns will be reported in mosaics which represent the response detail by Lindsay et al. (in prep.). to semi-aquatic conditions. Patterned surfaces are associated Threats to and losses ofpeatlands with various types of mire - raised 2.6 in the British Isles mires, aapa mires and palsa mires. Peatlands clearly assignable as raised Similar features are also widespread on bogs have always been localised in patterned tundras in the arctic regions Britain. In a study to be published by of the USSR, Canada and Alaska. The NCC (Bragg et al. in prep.), the major Sutherland and Caithness bogs original concentrations oflowland represent the most southerly and raised bog in Britain were examined for oceanic occurrence of these marked changes in land-use since the middle of patterns over a wide area and are also the last century. Between that time and unusual in being developed mainly on 1978, 84% of this habitat was found to blanket bogs. Whilst there is a have vanished through afforestation, superlicial resemblance between agricultural reclamation and British blanket bogs and certain types commercial peat-cutting; the increasing oflow arctic wet tundras, the latter role of afforestation in this process is occur in areas a flow precipitation, especially noteworthy. Much of the where the winter produces remaining area of raised bog has been drought conditions and the underlying severely damaged by burning and permafrost causes flooding in summer. draining, leaving only 6% of the original The occurrence in Britain of a naturally 13,000 ha as still vigorously-growing treeless tundra type of ecosystem far to Sphagnum-dominated bog. In total, the south of its main circumpolar therefore, 94% of the resource has been distribution and at very low altitudes is lost, more than half of this since 1945. If also a feature of great ecological and that rate of attrition is allowed to bioclimatic interest It illustrates how continue, the remainder will be lost in completely different sets of 30years. environmental conditions can produce Blanket bog remains a far more a convergent response in vegetation extensive type than raised bog, though and substrate development much has been lost or degraded by the 28 same processes of change. Higher was especially interested in them level bogs are especially prone to (Scottish Peat Committee 1968), but damage by erosion of the peat, concluded in 1962 that these deposits beginning with gullying and ending in were not worth working commercially denudation. Fire and grazing under the economic conditions then have been so widespread and long prevailing. Recently, there has been continued that the proportion of the total renewed interest in the possibilities of large area of blanket bog remaining large-scale peat-working, but there is quite natural and undamag~d is now no reason to suppose that economic quite small, and nearly all of it is in constraints have changed significantly, Scotland. notably the distance from markets. So Blanket bog is now under intense far the extraction is mostly local and threat in Britain, mainly from small-scale, around the edges of the afforestation. Extensive areas have main peatland masses. However, the been planted in Wales, the Cheviots possibility of major EEC funding for and the Southern Scottish Uplands. commercial peat extraction (The Extensive flow-lands in Wigtown district Scotsman, 5 December 1986) may affect are already widely afforested. Again, the economics of working peat in 30% of the blanket peat on the Kin tyre Caithness and Sutherland. peninsula has been lost to forestry since 1946 (Nature Conservancy Council 1986), as have numerous scattered areas in both the western and the eastern Highlands. On Caithness and Sutherland peatlands about 67,000 ha are planted or programmed for planting, and, even though not all of this is planted yet, afforestation has been so scattered that only eight out of 41 hydrological systems remain free from some planting. Planting has taken place up to the edge of many patterend bog systems. Ireland, another major stronghold of European blanket bog, is also seeing a marked decline in this habitat. Indeed, bog systems generally are under great threat in Ireland. Ryan & Cross (1984) quantified the rates of exploitation for all Irish peatland types. They found that blanket bogs were less damaged or modified than other peat bog types, yet, even so, some 207 ,900 ha had been damaged. This amounts to 27% of the total blanket bog in Ireland, while in all nearly 50% oflrish peatlands have been lost as natural ecosystems. Sue h loss has been piecemeal with no planned policy for conservation of key sites (van Eck et al. 1984; Bellamy 1986). There have been and there still are plans to extract peat from Caithness and Sutherland both for fuel and for horticultural uses. The area contains vast reserveB of deep peat, and the Scottish Committee set up in 1949 29 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H NCC's Upland Bird Survey in Caithness and Sutherland Introduction wigeon, common scoters, red-breasted 3.I The mountains and moorlands of Britain mergansers, greenshanks, red-and have an ecologically diverse and black-throated divers, common gulls distinctive bird fauna containing and arctic skuas from the flows around outlying and insular populations of Forsinard. In a vivid description of the species which belong either to high Caithness flows, Yeates (1948) drew altitudes or to northern latitudes in attention to the occurrence here of continental Europe. Of the various types small mainland colonies of arctic skuas, of upland habitat, the wet moorlands whilst Rankin (194 7) discussed the with large expanses of blanket bog are breeding black-throated divers; both a particular feature of the highly authors mentioned some of the other oceanic British climate, and their species emphasised by Harvie-Brown associated bird fauna is also of & Buckley. Assessment of conservation outstanding interest. The bird value came much later. Ratcliffe (1977a) community of these northern peatlands regarded the Caithness and Sutherland is especially rich in of waders flows as the most important blanket and represents an unusual avifauna, bogs in Britain for variety of bird showing affinities with those of both species, and Fuller (1982) stressed the boreal mires and arctic tundra. unusualness of the bird assemblage of Blanket bog is a naturally treeless these northern moorlands in his study of ecosystem lying latitudinally within the British bird habitats. boreal and cool temperate forest zones. By 1970, the conservation importance Despite certain resemblances, it differs of the Caithness and Sutherland from arctic tundra in that its origins peatlands, both for vegetational depend not on permafrost but on a cool features and for birds, was realised and and extremely humid climate. In an initial selection most important Europe, blanket bog reaches its areas suggested. While it was greatest development in the far north of recognised that this choice was based Scotland, where its extent and variety of on extremely fragmentary and form represent one of the most qualitative survey information, it was remarkable vegetational features of evident that some conservation Great Britain. Our concern has thus measures had to be achieved whilst been to record and evaluate 'the further surveys were undertaken. By ornithological character of this the late 1970s, there were clear portents important habitat in parallel with survey that transformation of these great and assessment of its vegetation. blanket bog systems on a massive scale, Earlier writers on ornithology made through afforestation, was becoming brief reference to the breeding bird ever more likely. Moreover, while fauna of the boggy flat moorlands quality of the best areas for breeding ('flows') of east Sutherland and birds was assessed largely according Caithness. Harvie-Brown & Buckley to species diversity and population (1887, 1895) describe the great flow land density of notable species, it had of this district, with its numerous dubh become clear that the total population lochans, as an important nesting haunt sizes for some species had both of red-throated diver, greylag goose, national and international importance. greenshank, golden plover, dunlin. red This gave a new dimension to the survey grouse, wigeon and five species of gull. and evaluation of the ornithological During the earlier part of the present interest of the northern Scottish century, the area appears to have been peatlands, as the basis for their little visited by ornithologists, but a few conservation. egg-collectors came in search of the In 1979, NCC launched a programme rarer species. It became known as of breeding bird surveys of moorlands perhaps the main breeding area of the likely to be affected by afforestation, common seater in this country. In 1900 and this has particularly concentrated and 1901, S. Steward, a notable on Caithness and Sutherland. Its aims oologist, recorded nesting greylags, were fivefold: 31 o to identify, from sites surveyed, range, over 80% of sites (62of77) lay in breeding bird assemblages of high the range 550-950 with sites nature conservation interest in terms clustered around the mean value of 67 4 of species diversity and population ha 17 4 sd). Most sites were surveyed density; in only one year but some were visited o to collect data to assess and identify in two or more seasons. A few were habitat features important to the surveyed for up to five consecutive breeding birds and from these years in order to investigate whether associations to predict the location of there were medium-term population other areas of high ornithological changes. Whilst in the early years of the interest; survey the emphasis was placed on o to estimate the size of the popula lions recording waders and wildfowl, more of breeding birds (especially recently all species of birds waders) dependent on the peat flows encountered on survey sites have been of Caithness and Sutherland; recorded. o to understand the effects that rapid The selection of sites was made so as changes - especially those resulting to include those thought likely to be from afforestation - would have on important as well as others giving a the birdlife of these wetlands; range of quality typical of the region as o to make recommendations for the a whole. The sites were chosen to conservation of wetland bird include many ~xamples of all the major assemblages within Caithness and peatland habitats (see Chapter 2) within Sutherland. the total range of types occurring in To these ends, sample areas were Caithness and Sutherland. Thus one of surveyed in Caithness in 1979, 1980 and the aims of the project has been to 1984, and in Sutherland from 1980 to assess typical breeding densities over 1986. The results of these surveys have the whole of the peatlands, and not just been or will be published elsewhere on the sites with exceptional (Symonds 1981; Langslow & Reed 1985; de1Gslt1es. By relating varying density to Reed & Langslow 1985, in press and in readily surveyed ecological features, it prep.; Reed, Langslow & Symonds then becomes possible to estimate 1983a, 1983b; Barrett et al. in prep.). densities in other parts of the region Additionally to NCC 's survey work, which have not been surveyed for birds. the Royal Society for the Protection of In this way, the total of the breeding Birds (RSPB) carried out other studies populations in the region can be within the same region between 1980 assessed with some degree of and 1986. Slightly different methods confidence, and individual areas were used to allow larger areas to be placed in context. at the expense affine-scale detail. This work has extended the area 3 .2 Programme of ornithological for which data are available and Sllllt'Wys permitted an independent assessment Methods of the breeding bird assemblages of The method used was a modification of some areas. RSPB's results have been the territory-mapping census. A presented as a series of internal detailed description of methods used reports. In 1985 RSPB surveyed eight and tests employed to ensure consistent sites in Caithness and Sutherland using and accurate recording and NCC's methodology (Birkin, Hayhow & interpretation of results is presented in Campbell 1985). The results of this the Appendix. survey have been used to extend the scope of the NCC data-base. Distribution of sites surveyed NCC and RSPB quantitatively The of sites surveyed by NCC surveyed waders on a total of 77 sites betwe~m 1979 and 1986 and by RSPB in (sample areas) in Caithness and 1985 is shown in Figure 3.1. In Caithness, Sutherland. The range of size of the sites most sites were located in the centre of was 200-1,025 ha. Despite this large the district, although two sites were 32 Figure 3.1 Distribution of sites surveyed for Key breeding waders (1979-1986) superimposed on the blanket bog shown in Figure l.2. Blanket bog Eight sites surveyed by RSPB ln 1985, using 8 Ornithological survey sites NCC methods, are included 33 surveyed in the north. In Sutherland, groups - waders, other waterfowl, most sites were located in the east and raptors and scavengers, pa:ssemrtes centre, but within this area sites were and a miscellany of other types. The geographically widespread and waders are outstanding in overall covered the full range of peatland numbers and diversity, and the habitat types. Indeed, across both occurrence of at least 15 breeding districts the sites surveyed ranged from species reflects the variety of peatland coast to coast. Montane habitats and and open water habitats. Golden steeply sloping moorland at high plover, dunlin, greenshank and curlew altitudes were generally not included in occur with high constancy in the sample the sample of habitats surveyed. This areas and so have large total will mean that the sample of sites does populations within the region. Common not contain a representative sample of sandpiper and snipe are also those species, such as ring ouzel and widespread and numerous, but several wheatear, which favour such ground. species are somewhat local lapwing, Separate RSPB/NCC surveys had oystercatcher, redshank and ringed previously been made of two of the plover. most important birds of these steep and The overall densities of waders at rocky upland habitats, the peregrine different sites varied considerably and the golden eagle. There were a few (Figure 3.2). In Caithness, densities for sites in which montane or steep land all breeding waders ranged from 0 · 9 to was included. These confirmed the 14 · 0 pairs/km", and in Sutherland from 2 general absence of waders and 0 · 2 to 14 · 3 pairs/km • overall mean wildfowl from these habitats. density of breeding waders was 5 · 4 2 pairs/krn , but this excludes steep, Composition ofthe peatland montane and other areas unsuitable for 3.3 breeding bird :fauna waders, as explained in Chapter 4. The 'l'he bird fauna in spring and summer number of wader species breeding on includes several taxonomic/ecological particular sites varied from one to ten. Figure 3.2 Densities of all breed mg waders on !he survey snes in Caithness and Sutherland Frequency of sites 15 10 5 2 3 4 5 6 7 8 9 lO ll 12 13 14 15 Densities of breeding waders (pairs/km:) 34 In Scandinavia, several of the anthropogenic habitats for both feeding breeding birds of open peatland and breeding. The greenshank and belong to the boreal-subarctic forest wood sandpiper have adapted to zone rather than to the arctic completely treeless open moorland tundras - greenshank, wigeon and habitats in Scotland, though they do three British rarities, wood sandpiper, sometimes also occur in open bogs in ruff and Temminck's stint They are. Scandinavia (Hakala 1971). The recent however, associated with forest lakes discovery of ruff breeding in the and open marshes, in which is Caithness and Sutherland peat bogs is usually a considerable area of highly unusual, since this species is transitional habitat consisting of very usually found in sedge marshes, often open woodland with increasingly within forest, in more northern areas of stunted and checked trees as the Fenno-Scandia, or in unimproved wetness of the ground ,,...,..>T''"""'"'"' agricultural grasslands in the European (Sammalisto 1957; Moen 1985). Such low countries. This is also the first habitats were once well represented in known breeding of ruff in Britain the Spey Valley pinewoods and evidently from the arctic-subarctic supported a small and isolated population, for the recent colonisation population of greenshanks. The dense of a few English localities appears to be closed plantations of the new British from the temperate European forests do not provide these transitional population. These are examples of open forest habitats on anything but a ecological divergence which are of temporary and fragmentary scale. considerable interest to students of Nethersole-Thompson & Watson (197 4) evolution and speciation, since this is attributed the disappearance of the one of the ways in which new forms of greenshank population of the Speyside organisms evolve. pinewoods to commercial afforestation The occurrence of a notable group of of its main breeding and feeding northern wading birds as 'fringe' habitats, open heaths and marshes species in this part of Scotland - wood within the forest area (see section 6.1). sandpiper, ruff, Temminck's stint and Whilst golden plovers in Scandinavia red-necked phalarope (D. & M. are mainly birds of open tundra, they Nethersole-Thompson 1986) - is also of also have a forest heath and bog niche much interest as a 'biological and they formerly bred sparingly in barometer' of climatic change. They are such habitats on both Speyside and all still rare, but it is supposed that their Deeside. They now appear to have tendency to appear in Britain is the disappeared from such habitats in response to an increase in the Scotland. Even where former breeding incidence of 'northern' climatic places been left as unplanted conditions in the form of colder springs enclaves of up to l km in diameter during the last two or three decades. within Kielder Forest, most of the Waterfowl are associated especially golden plovers have gone: the with open waters varying in from ungrazed and unburned vegetation is tiny dubh lochans to large lochs, They now too tall, quite apart from any include black-throated and possible influence of predators. red-throated divers, greylag goose, Some bird species show interesting common scoter, wigeon, teal, mallard ecological adaptations to the British and red-breasted merganser. Common environment differing from those and black-headed gulls nest in small characteristic of populations throughout colonies. their larger Eurasian range. The golden At some sites predators and plover population in Britain is the scavengers were regularly seen, with southernmost representative of a golden eagle, hen harrier, merlin, circumpolar species-complex, and it peregrine, short-eared owl and raven has developed an interesting cline in present Some pairs of merlins, hen plumage, a partial pattern harriers and short-eared owls breed on and a local dependence on the peatlands, but the other species 35 nest on rocks and hunt over the bogs. weather(cfThompson, Thompson& The arctic skua is a different kind of Nethersole-Thompson 1986) or may predator breeding in small groups on reflect slight differences in the average the flows. The methods used here were quality of sites selected for survey in not appropriate for the accurate each year. Low densities of 0 · 9 calculation of raptor breeding pairs/km" were reported by D & M. densities, but attention is drawn to the Nethersole.!T'hompson (1986) over their general importance of this area for study area of 3,250 ha in north-west raptors (Table 8.1 and Figures 3.4f-i). Sutherland, although in south-east The remaining species are mostly Sutherland in the 1960s they found that those with a fairly widespread densities were higher, with distribution on moorland in Britain. approximately 2-3 pairs/km<. They include red grouse, meadow pipit, skylark and, as streamside nesters, dipper and grey wagtail. Densities for individual species of waders were calculated in two ways. For those which occurred throughout the peatlands and were found on a majority of survey sites (golden plover, dunlin and greenshank), the mean densities were calculated for all sites surveyed. Thus the mean includes zero values for the few sites where birds were not present. For more local species of waders occurring on few sites, means were calculated in two Golden plover ways-first as described above and secondly only for those sites holding Breeding grounds vary widely, from breeding birds. This latter value wet pool and hummock flows, through represents local abundance where the drier cottongrass and bog species is present. For widespread (Trichophoreto-Eriophoretum typicum waders such as golden plover, dunlin of Table 2.1) to dry heather moor, and greenshank the two methods give grassland and stony moraines. Small fairly similar densities. numbers of golden plovers also nest on the high plateau blanket bogs, 3.4 Waders grasslands and dwarf shrub and moss Golden plover heaths within the montane zone. The Golden plovers were the most common feature is very short abundant breeding wader found on the vegetation. Golden plovers often feed in peatlands of Caithness and Sutherland richer wet places or on grassland on the and were present on all but five of the 77 moor, but in some areas they regularly sites surveyed. resort to the improved pastures of The range of breeding densities of enclosed fields beyond the moorland golden plovers is shown in Figure 3.3a. edge (Ratcliffe 1976). Mean density on the sites surveyed was l ·76pairs/km2(± 1·22sd). The Dunlin breeding distribution of golden plovers Dunlins were the second most in Caithness and Sutherland is shown in abundant breeding wader, being found Figure 3 .4a. at 71 of the 77 sites surveyed in When overall densities for survey Caithness and Sutherland. Their sites in any year are calculated, there breeding distribution over the whole of are slight annual differences. These the two districts is shown in Figure 3.4b. differences may reflect year-to-year The range of densities of dunlin on differences in factors affecting the the peatlands is highly skewed (Figure breeding population such as spring 3.3b). The density distribution has a 36 long right tail, since a few sites hold the density of breeding dunlin is very high densities compared with related to the abundance and those over much of the rest of these availability of their food supply and that blanket bog areas. the main function of territorial behaviour is to disperse the populations in relation to food". This is most probably also the case on Scottish peatlands, since breeding density is strongly determined by the abundance of dubh lochans for feeding (section 4.1). Other previous studies of dunlin have shown them to be strongly site-faithful (Soikkeli 1970; D. B. A. Thompson pers. comm.). Greenshank Greenshanks were the third most abundant breeding wader on the peatlands of Caithness and Sutherland Dunlin and were found on 58 of the 77 sites surveyed. Their breeding distribution The mean density was 2 · 39 pairs/km" in the two districts is shown in Figure ( ± 2 · 49 sd). In view of the skewed 3.4c. breeding density distribution, which is The range of breeding densities of a function of this species' semi-colonial greenshanks on the survey sites was breeding habits, the median density also skewed (Figure 3.3c). The mean (1 · 76 pairs/km~) may be a more density was 0 · 31 pairs/km:: ( ± 0 · 29 sd), biologically meaningful measure whilst the median density was 0 · 21 abundance. As with golden plover, pairs/km2. The range of densities found there were year-to-year variations in is similar to that described by D. & M. breeding density. These year-to-year N ethersole!J'hompson (1986) in studies differences are probably largely due to in the north of Scotland. In one study inclusion or exclusion of a small number area in north-west Sutherland they of high-density breeding sites in the found greenshank densities varying sample surveyed. Annual variations in between 0 · 2 and 0 · 9 pa:irs/km2 over an weather may also be important in 18-year period. affecting breeding densities. D. & M. Nethersole-Thompson (1986) reported densities ranging between 0 · 62 and 2 · 7 pairs/km2 on peatlands in Sutherland, with exceptional breeding densities of up to 25 pairs/km" over small areas (five pairs in 20 ha). Their range of 2 · 04-2 · 70 pairs/km~ over nearly twenty years in one study area of 7 40 ha equates well with average densities found in this study. 'v'"'"''"'(l966, 1970) investigated dunlin feeding ecology and breeding density on arctic and subarctic tundra. He found that breeding density related closely to the abundance of Greenshank invertebrate food, which in turn was determined by habitat features There seemed to be relatively little including the number and spacing of year-to-year variation in breeding pools. Holmes (1970) concluded "that densities. Such variation as there was 37 can be explained by the known effects Breeding areas include a range of of spring weather on breeding numbers moorland habitats from deep bogs to and success {Thompson, Thompson & dry heath and grassland, but curlews Nethersole-Thompson 1986). are often more numerous on the rough Greenshanks show a more complex and often rushy enclosed pastures of use of the peatland habitats than some the marginal and crofting lands. of the other breeding waders. The species requires semi-aquatic Common sandpiper food-gathering areas either along fairly Although a species associated with productive rivers or at the margins of loch-edge and riverine habitats, lochs and pools. However, nesting may common sandpipers were recorded occur at a distance of up to 3 km away, breeding on 41 of the 77 study sites on either dry or boggy moorland which (Figure 3.3e). may even contain rock outcrops. During Breeding densities for Caithness and the nesting period, adult birds fly Sutherland were 0 · 39 pairs/km" between feeding and nesting areas, ( ± 0·35 sd) on those sites where and, after hatching, the young are led breeding birds were present, but for all down to the wet feeding areas, which survey sites combined the mean are rich in invertebrates. density recorded was 0 · 21 pairs/km" Thus greenshanks favour gently ( ± 0·32 sd). However, this is probably an contoured peatlands in areas where underestimate. Common sandpipers lochs and pools are plentiful, and, breed mainly along watercourses, and where available, habitats range from the survey methods are less efficient in patterned blanket bogs to shallow this discrete habitat than over the valley bogs within drier morainic expanse of blanket bog. It would Calluna heaths. In the far west of perhaps be more valid to express Sutherland; nesting can occur in areas abundance of this species with res:peict of shallow peat strewn with glacial to the total length of suitable erratics (D & M. Nethersole-Thompson water's-edge habitat(cf D. & M. 1979, 1986). Nethersole-Thompson 1986). Common sandpipers are highly Curlew faithful to territories where they have Curlews were the fourth most abundant nested successfully in previous years: species of breeding wader on in a study in the Peak District over 85% peatlands in Caithness and Sutherland of a colour-ringed sample returned to and were found at 46 of the 77 sites the same in successive years surveyed (Figure 3.3d). Their mean (Holland, Robson & Yalden 1982). density was found to be 0 · 61 pairs/km" ( ± 0·41 sd) on those sites where they Other wader species were present and 0 · 31 pairs/km" After the species listed above, ( ± 041 sd) over all 77 sites. breeding wader species in order of frequency of breeding records on the survey sites were snipe, lapwing, redshank, ringed plover and oystercatcher. Snipe are partial migrants, widespread in the peatland areas of Caithness and Sutherland. The breed ing distribution and abundance of snipe is poorly known owing to the very secretive habits of the species. Snipe were found at 45 sites, but breeding was proved at only 27 (Figure 3.3f). However, the territory-mapping Curlew methods used undoubtedly failed to locate many birds. The survey detected 38 an average of0·3 l pairs/km" ( ± 0·29 sd) Ringed plovers are also partial on those sites where birds were proved migrants to the peatlands of Caithness to breed, but for all survey sites and Sutherland. Their breeding combined the mean breeding density distribution is widespread and includes 2 was 0 · 11 pairs/km ( ± 0·22 sd). AB with inland areas. Ringed plovers were other species, the distribution of snipe found breeding on 12 sites (Figure 3.3i), was found to be localised within sites and with a mean breeding density on those strongly determined by the distribution sites that were occupied of 0 · 29 of suitable feeding habitat wet, rank pairs/km2(± 0·23 sd). The mean density flushes with abundant cover of}uncus over all surveyed sites was 0·05 species. D. & M. Nethersole!T'hompson pairs/km" ( ± O· 14 sd). (1986) found densities ranging between Oystercatchers are summer visitors 0 · 18 and 0 · 31 pairs/km" in a 3,250 ha to inland breeding areas within study area in north-west Sutherland. Caithness and Sutherland. They have a They considered that this widespread breeding distribution, but underestimated the abundance there is little information on breeding because birds favoured acid grassland numbers within the two districts. areas within the peatlands. The major Oystercatchers were found u.1.c;t::ui.u\..l problems of surveying breeding snipe on only seven of the survey sites (Figure in other wetland habitats have been 3.3j). The mean density on these sites 2 investigated by Green (1985). was 0 · 26 pairs/km ( ± 0· 16 sd), whilst Lapwings are partial migrants and over all sites it was 0 · 02 pairs/km• are widespread, although commoner in (±0·09 sd). Caithness than in Sutherland. In winter, The woodcock is a secretive wader lapwings leave inland and upland areas with a localised breeding distribution. to winter on the coasts and in the Though it is primarily associated with lowlands. Lapwings bred on 23 of the 77 woodlands, single pairs were recorded sites surveyed (Figure 3.3g). They are as on two sites and birds have mainly a species of grassland and been recorded as present on two arable and not strictly a peatland further sites during the last decade. wader, and they showed a strong affinity for those parts of sites with marginal agricultural improvement, either through drainage or as a result of reversion of hill pastures. The mean density on sites where they occurred was 0 · 66 pairs/km' ( ± 0·63 sd), whilst over all 77 sites the mean density was 2 0 · 20 pairs/km ( ± 0·45 sd). The highest density recorded was of 1·92 pairs/km2 on a peatland in Caithness. Redshanks are partial migrants to Wood sandpiper peatland areas of Caithness and Sutherland, with a somewhat localised The wood sandpiper occurs in distribution within the two districts Caithness and Sutherland as a rare owing to their habitat requirements. summer visitor and breeding species They were found to be commonest in (D. & M. Nethersole-Thompson 1986). Caithness, with fewer birds using It is nationally rare, with never more peatlands in Sutherland. Redshanks than 10 pairs recorded as breeding at bred on only 14 of the survey sites one time in Britain. Wood sandpipers (Figure 3.3h) and were present on five are thought to occur regularly in other sites. Densities were generally small numbers on the peatlands, the low. The mean density on sites where vast extent of which results in few 2 they occurred was 0 · 30 pairs/km ( ± confirmed records; however D. & M. 0·17 sd), whilst that over all survey sites Nethersole-Thompson (1986) reported was only 0 · 06 pairs/km' ( ± 0· 14 sd). two breeding pairs on the same 39 Sutherland moss in 1968. During fue (Gomersall, Morton & Wynde 1984). surveys fue species was recorded from Red-throated divers were present on two sites in Sutherland. half the sites surveyed, wifu two pairs Red-necked phalaropes breed breeding on one site, one pair breeding irregularly within the area, but the on each of a furfuer 19 sites and birds species has declined in numbers as a present but with breeding unconfirmed breeding bird in Britain and Ireland on 15 furfuer sites. Breeding occurs on and its main stronghold is now in very small lochans or pools, and birds. Shetland. A substantial proportion of fly to feed on either large lochs or the one 1981 breeding site in the Caithness :;ea. With these nesting habits, it is and Sutherland peatlands was later possible for red-throated divers to ploughed for afforestation. No birds breed in areas of highly patterned mire were seen during the surveys. where there are no extensive· areas of Temminck 's stint is a very rare openwatPr. breeding visitor to the peatlands of Caithness and Sufuerland. It was not recorded from fue survey sites, although it is known to have bred wifuin the area. The ruff is a norfuem breeding wader, wifu very small numbers breeding in fue Low Countries and in England. Of particular interest is a recent record of confirmed breeding by ruff on fue Caithness and Sutherland peatlands. None were seen on survey sites in fue period 1979-1986. Pectoral sandpipers have been seen with increasing frequency in Scotland in recent years (Thom 1986). A male of this Siberian-North American species Red-throated diver displayed over a flow in Caithness during the spring of 197 4 (Byrne & Thom (1986) records the considerable Mackenzie-Grieve 197 4). extension of the breeding range in the early 20th century, and numbers are 3.5 Other waterfowl still increasing in some areas. Red~throated diver Red-throated divers have a boreal Black--throated diver high arctic world distribution and The black-throated diver is a rare breed throughout the peatlands of species in Britain whose stronghold is in Caifuness and Sutherland, moving to norfuem Scotland. Elsewhere, it has a the coast and men soufuwards in winter. strongly no1them distribution Although there has never been a extending to the Arctic. Breeding comprehensive summer survey of throughout Caithness and Sutherland, numbers, Thom (1986) suggests that black-throats select large lochs, for both ''substantial numbers", probably up to nest site and feeding area (in contrast to 200 pairs, breed in Caithness and red-throated divers) during the Sutherland. This amounts to the major breeding season. Lochs with remote part of the mainland breeding islands are particularly favoured, so population. Other mainland areas, such that many lochs which are otherwise as Argyll, hold smaller numbers suitable but without islands are not (Broad, Seddon & Stroud 1986), whilst used. Campbell & Talbot (1987) the greater part of the British population document the very low breeding breeds on the islands ofShetland (700 success of the British population, and pairs), Orkney (67-80 pairs) and the low productivity has been recorded for Outer Hebrides (39-46 pairs) black-throated divers in Sutherland in 40 previous years (Bundy 1979). An emergent vegetation for nesting cover. important component of this failure Hence, most areas of ornbrotrophic is fluctuation in water-level of the peatland and dubh lochans are breeding loch (Rankin 1947; Dennis unsuitable, and little grebes appear to 1976). Modification of the catchment prefer areas where there is some hydrology owing to peatland drainage natural nutrient enrichment giving a can be expected to reduce the time productive aquatic flora. lag between precipitation and run-off and Urns increase water-level Slavonian grebe fluctuations. The Slavonian grebe is a very rare breeding summer visitor to Caithness and Sutherland. Thom (1986) records its breeding in Sutherland first in 1929 (four pairs) and then irregularly until the 1960s. In Caithness, first breeding also occurred in 1929, with up to 10 pairs recorded until at least 1975, although none have been recorded since. The Slavonian grebe, like the little grebe, Black-throated diver prefers enriched conditions and is thus not found on the more oligotrophic Similarly, some traditional waters of the extensive peatlands. This non-peatland nesting lochs in more species was not recorded on the sites lowland areas have probably been surveyed. rendered less suitable owing to low land hydro-electric or water extraction Grey heron schemes. Thus remote peatland lochs The grey heron is a scarce resident could have become more important for breeding species in Caithness and this species owing to their lack of water Sutherland, although some individuals, engineering schemes or other particularly young birds, leave the hydrological modification. region in winter. Here they are at the The total British population is north-western limit of their Palaearctic estimated at 150 pairs, of which 38 breeding distribution. Birds were were found in Caithness and present on 14 survey sites, with Sutherland (Campbell & Talbot 1987). breeding by one pair recorded on each Black-throated divers were present on of two sites. The 1954 census found two 23 survey sites, with two pairs on one heronries in Caithness, with 12 pairs, site, one pair on each of eight other sites and seven heronries in Sutherland, with and birds present but with no evidence 33-34 pairs (Thorn 1986). More recent of breeding on 14 further sites. information suggests no major change With low productivity, small numbers in status within the area (M. Marquiss and a restricted distribution, the pers. comm.). British population of black-throated divers is at considerable risk. RSPB Whooper swan has recently initiated a major Whilst primarily winter visitors from programme of research into the Iceland to large lowland lochs in breeding and ecology of this species in Caithness, birds occasionally breed in the north of Scotland. Britain and not infrequently summer on Caithness and Sutherland peatlands. Little grebe Whooper swans were present on two The little grebe is a rare breeding bird sites surveyed by NCC teams. in the peatlands of Caithness and Sutherland, found nesting on only one Pink-footed goose survey site. It requires shallow lochs Pink-footed geese are winter visitors with abundant submerged vegetation from Iceland, with a major wintering for feeding and sufficient dense locality close to south-east Sutherland 41 (Owen, Atkinson-Willes & Salmon 1986). origin (Thom 1986). There are few good Birds were present on two survey sites data on numbers of breeding greylags, during the summer but there was no but Thom (1986) refers to 11 pairs found evidence to suggest that these birds in Caithness in 1977 and considers the were anything but delayed migrants. whole native British stock (including those in the Western Isles) to be Greenland white-fronted goose between 2,500 and 3,000 birds, or 500 to Greenland whitefronts have 700 breeding pairs. traditionally fed and roosted on peatlands throughout their world range, and their present winter distribution in north and west Scotland, Wales and Ireland closely reflects the distribution of oceanic blanket bogs and raised bogs. Their status in Britain has been the subject of recent research (e.g. Stroud 1985; Greenland White-fronted Goose Study 1986). Laybourne & Fox (in press) Grey lag goose summarise the past and present status of wintering Greenland white-fronted NCC surveys found three pairs geese in Caithness. These geese have breeding at one site, two pairs breeding been present on the peatlands since at at another site and one pair breeding least the 1880s. Harvie-Brown & Buckley on each of a further five sites. Birds (1887) recorded that the keeper at were present at 27 further sites, Strathmore bred pinioned birds from although many of these records relate wounded geese shot on the peatlands to flocks of moulting birds in around the Lodge. More recently, midsummer. In 1986, a large moulting significant numbers have wintered in flock was discovered on Loch Loyal. By the agricultural lowlands, but geese still early July, numbers had increased to use the peatland areas for roosting and about 1,200 birds, which must represent feeding, especially in autumn. a major proportion of the native stock Laybourne & Fox (in press) point out breeding in Sutherland and possibly that the bog-feeding Greenland Caithness. This moulting aggregation is whitefronts represent the only of significant conservation importance, European goose still wintering on and clearly further study is required to natural (rather than agricultural or semi establish the provenance of these birds. natural) habitat. Considering that "conservation is not merely concerned Wigeon with the establishment of reserves, but Wigeon breed in both Caithness and is the maintenance of natural diversity", Sutherland (Figure 3 .4d) and also winter they state that the protection of these within the region, though wintering peatland areas for Greenland birds are largely confined to the large white fronts is of critical importance. lowland lochs of Caithness and south There is recent evidence that east Sutherland. Breeding pairs are peatlands in Sutherland are also used thinly distributed across peatland by this race of geese, at least at times in areas. Sharrock (1976) suggested that the winter (Greenland White-fronted the Scottish breeding population Goose Study 1986), but further survey is amounted to about 400 pairs. required to establish the full extent of Of the 72 sites surveyed for wildfowl, their occurrences in this district 29 (40%)held wigeon. One site held six breeding pairs, a further 15 sites held Greylag goose from one to three pairs, and birds were In contrast to most breeding greylag recorded as present on another 13 sites. geese in Britain, those of north-west Their secretive nature during the Scotland are considered to be native in breeding season means that they were 42 undoubtedly under-recorded. After teal, mallard were the second most commonly recorded wildfowl Teal species, being found on two-thirds of both breed and occur as winter the sites (49of72). Between one and visitors in Caitlmess and Sutherland. three pairs bred on 30 sites, whilst birds The very secretive nature of breeding were recorded as present on 19 further teal has meant that information on sites. numbers and distribution within the region is scarce. Whilst widespread. Pintail they appear to be nowhere common Pintail occur as a rare breeding duck and decrease in abundance in west within the two districts. Between 11 and Sutherland. 41 pairs nested in Great Britain annually Birds were recorded from from 1974 to 1984, including up to four three-quarters of the survey sites (53 of pairs breeding fairly regularly in north 72), making teal the commonest Caithness and occasional breeding recorded wildfowl species on these records from north-west Sutherland peatlands. Between four and seven (Thom 1986). Pintail were recorded as pairs were recorded as breeding on six present on one survey site in south sites and one to three pairs on 27 further central Sutherland. sites, and birds were recorded. although with no evidence of breeding, Tufted duck on 20 further sites. Tufted duck breed in small numbers in Fox (1986a) gave details of the north-east Caitlmess and north-west breeding ecology of teal on a Welsh Sutherland, but they tend to select more peatland, showing that position of nutrient-enriched lowland waters. nests is closely determined by the Additional birds visit the area in winter. location of standing water and Tufted duck were present on two demonstrating the importance of open but there were no confirmed records of water areas wit,\1in peatland for feeding breeding. and brood-rearing. Areas of peatland with extensive pools, such as the Common scoter highly patterned peatlands under The peatland lochs of Caithness and consideration, can be supposed to be Sutherland form a stronghold the highly attractive nesting habitat for teal. common seater within Britain (figure The blocking oflarge ditches cut within 3.4e). The current British breeding the peatland, with a resultant increase population has been calculated as in open water area, was shown to between 75 and 80 pairs, 30 of them increase the numbers of teal nesting within these two districts (Thom 1986; successfully (fox 1986a). It can thus be NCC and RSPB unpublished). An inferred that drainage of peatlands, unpublished collation of breeding data especially of pool systems, will be by RSPB, however, suggests that there extremely damaging to the quality of may be as many as 50 pairs breeding in teal nesting habitat. Caithness and Sutherland. This evidence confirms the status of these Mallard peatlands as the most important The mallard is both a resident breeding breeding area for this duck in Britain. bird and a winter visitor to Caithness Assessment of precise numbers is and Sutherland. Ecologically, mallard made difficult by the secretive nesting are adaptable and can utilise a wide of scoters in long heather some range of freshwater habitats. Thus, distance from open water, the unlike teal and wigeon, they are not disappearance of males early in the confined to predominantly peatland breeding season and annual areas within Caithness and Sutherland. fluctuations in the breeding population. There are no reliable estimates for Numbers appear to have reached a breeding numbers of mallard within the maximum in the late 1970s with a peatlands. Scottish population of almost 100 pairs. 43 and birds were present but with no evidence of breeding on 10 further sites. Goosander The goosander is a scarce brE~edmq bird in the area and is probably resident throughout the year. Thom (1986)·suggests that between 55 and 75 pairs breed in Ross and Sutherland. Both goosander and red-breasted merganser are subject to intense persecution in some areas of Caithness and Sutherland owing to their alleged depredations on fish. Goosanders were Common seater breeding on one survey site and birds were found to be present on five further Common scoters were recorded sites, all in Sutherland. from eight survey sites in Caithness and Sutherland. Between one and five pairs 3.6 :Raptors were seen at each of four sites in Henha.nier Caithness and three to eight pairs at Hen harriers are mainly resident in each of four further sites in Sutherland. Caithness and Sutherland (Figure 3. 4f), Whilst these numbers are small in although there is a considerable absolute terms, the region holds a high dispersal of birds in the winter. Watson proportion (about 40%) of the total (1977) documented the persecution of British population of this species, and hen harriers in Britain during the last the protection of its nesting and feeding century by gamekeepers and others. areas is a high conservation priority. Available evidence suggests that the remote peatlands of Caithness and Golden eye Sutherland were one of the last Golden eye are common winter visitors mainland strongholds for this species, to, and passage migrants through, and birds bred in this area until the tum Caithness and Sutherland but have yet to of the century. The area was also one of be proved to breed. They are currently the first to be recolonised, and Watson increasing their breeding range within {1977) gives details of summer Scotland (Dennis & Dow 1984), but recoveries of ringed birds from Orkney breeding appears to depend on the found in Caithness Sutherland availability of suitable nest-sites. during 1952-1970. By 1975, numbers had were present on 11 of the survey sites increased yet further in Sutherland but visited, but all these appeared to be hen harriers were still sparse in wandering migrants or non-breeding Caithness. birds. Red-breasted merganser This species has a boreal-low arctic distribution. Caithness and Sutherland hold both resident breeding and winter-visiting red-breasted mergansers. Although no population figures are available for the two districts, the species is widespread and thought to be currently increasing. Red breasted mergansers were found on 19 of the survey sites. Three pairs were breeding on one site, one or two pairs bred on each of a further eight sites, Hen harrier 44 It appears that this recolonisation usually nests on crags, no breeding was provided a focus for further expansion recorded in this survey. It is clear, in mainland Scotland. Although however, as other studies have numbers have now considerably indicated (Watson, Langslow & Rae increased from only a few years ago, 1987), that the blanket bogs are the species is still persecuted, important feeding habitat for significant especially in areas of high grouse numbers of golden eagles. production. In the early 1980s there were thought to be 30-35 pairs in Kestrel Sutherland, Caithness and Ross & There are no data on the size of the Cromarty (Thom 1986), but more recent kestrel population in Caithness and information suggests about 60 pairs in Sutherland. Whilst a few birds are Caithness and Sutherland (RSPB probably resident, the kestrel is largely unpublished data), though not all of a summer visitor here, but birds from these are strictly confined to peatlands. elsewhere also visit the area in winter. Hen harriers were recorded as Though more common in areas of present on 16 of 63 survey sites (26%) marginal hill pasture, pairs of kestrels but were proved to breed on only one bred on two survey sites (out of 56) and site in Sutherland. Most sightings of were present on 13 further sites. It is hunting birds in summer are thought to that peatlands are of some relate to breeding birds whose significance as feeding areas for territories overlapped survey kestrels in Caithness and Sutherland. although their nests were outside them. Merlin Sparrow hawk Merlins are small moorland falcons Sparrowhawks have a very localised found throughout upland Britain but distribution in Caithness and currently decreasing in numbers Sutherland, and, whilst they are mainly through much of their British range. resident, there is some dispersal out of, The total British population size is about and influx into, the area in winter. 600 pairs (Bibby & Nattrass 1986), of Sparrowhawks tend to be associated which at least 30 use the peatlands of with remnant native woodlands and Caithness and Sutherland (Figure 3.4h). also thicket-stage plantations, though Because of the difficulty in finding they sometimes feed over nearby nesting merlins, this map undoubtedly peatland. They are not so dependent on under-records their breeding peatland habitats as other raptors in the distribution. They probably occur more region and were recorded on only one or throughout the peatlands but at survey site (out of 60), in Sutherland. low density. They are partial migrants, and in autumn and winter merlins from Golden eagle Iceland also visit the region. Such North-west Scotland provides one of the information on breeding distribution as major breeding areas in Britain for there is suggests that the species is golden eagles. The 1982 national survey commonest in west Sutherland, identified 511 territories occupied by becoming scarcer further east into eagles (Dennis et al. 1984). There are Caithness. thought to be about 50 pairs of eagle One pair of merlins was found on currently breeding in Caithness and each of three sites (out of52), with birds Sutherland (R. H. Dennis pers. comm.), recorded as present on 13 further sites but some of these are coastal and thus but not nesting within the area cannot be considered to be dependent surveyed. Such a pattern of distribution on peatlands (Figure 3.4g). Thirty suggests that merlins are widespread territories contain significant areas of but nowhere common. Information peatland habitat. collected by the MBS team in 1986 Eagles were noted as present on a suggests that they are still subject to quarter of the sites (15 out of 60) persecution in some areas of surveyed for them, but, as this species. Sutherland. 45 11 further sites. This undoubtedly under-records their use of the area, since they are easy to overlook owing to their tendency to fly very high when hunting. Short-eared owl Short-eared owls have a scattered breeding distribution, mainly in Caithness. The population varies to some extent with the availability of prey and thus can be greatly enlarged afte:r 'vole years'. Though the species is resident, there is also considerable dispersal, mainly of young birds which leave the area where they hatch and settle elsewhere where there is abundant food. These wandering birds seem generally not to return to the breeding areas. Out of 67 sites, one pair was recorded Merlin as breeding on a Sutherland site and birds were present on three further In a study of moorland birds in sites. southern Scotland, Rankin & Taylor (1985) found a strong positive correlation Other species between the breeding density of 3.7 Red grouse meadow pipits and that of merlins. In Red grouse are a widespread and view of the feeding habitats of merlins, resident game bird found throughout such a relationship is hardly surprising, most of the area and belonging to the but it emphasises the ecological links endemic raceLagopus Jagopusscoticus, between one of the commonest and one part of the widespread willow grouse of the scarcest peatland breeding species-complex. Whilst it is abundant birds. Peregrine Peregrines are widespread in Caithness and Sutherland, occurring both coastally and inland in both districts (Figure 3.4i). The population of this region constitutes less than 1% of the EC population of the peregrine, but most of the latter conmsts of the Mediterranean race Falco peregnn us brookei. The peatlands support a much greater proportion of the nominate race Red grouse F p. peregrin us. Some 35 pairs breed inland and depend on the peatlands for elsewhere in parts of Scotland, there is their feeding territories. Whilst nest a special responsibility to safeguard sites occur on crags or in gorges, this endemic race. Although hunting takes place over a wide area widespread in Caithness and east and a great variety of prey, mainly Sutherland, grouse tend to be more birds, is taken (Ratcliffe 1980). localised in distribution in west Out of 60 sites, a pair was recorded as Sutherland, perhaps owing to the one site in Sutherland and greater fragmentation of their moorland birds were present and seen hunting on habitats. There is little good information 46 on population size, but birds were found population of 40 pairs found by Reed, on all survey sites and presumably bred Langslow & Symonds (1983b) on UBS on all. Earlier in this century there were survey in 1979 and 1980. When the a number of productive grouse moors in UBS surveys were compared with the area, especially in Caithness, but, as previous information, it was found that elsewhere, there has been a long-term there were at least six new breeding decline in numbers through much of the areas in 1979-80 compar8d with 197 4 tvvo districts, The causes are still being and, of the six sites surveyed in 1979-80 studied by the Grune Conservancy which had held birds in 1974, five held elsewhere in Scotland. Caithness has larger numbers - a significant increase also been a traditional area for the sport (Reed, Langslow & Symonds l983b). of 'grouse-hawking' with trained falcons, for the large, flat moorlands make it easy to follow flights of quarry over long distances and give the best chance of recovering the valuable hawks. Black grouse Black grouse are resident in Caithness and Sutherland. They are rare in Caithness but locally more frequent in Sutherland, and there has a been a slight extension in their range as the edges of new conifer plantations are colonised. Moss (1986) has recently reviewed the distribution of black Arctic skua grouse in Scotland and has shown that the species is ecologically more These results suggest that arctic tolerant of high summer rainfall than skuas are still increasing their range other grune birds such as capercaillie. within Caithness, although there is no This tolerance of high rainfall allows more recent comprehensive exploitation of peatland areas in the information than that of 1979-80. There wetter north and westofScotland. still appears to be suitable habitat Birds were recorded as present on unoccupied within Sutherland; although only two (of 67) sites, and the species Thom (1986) recorded one to three pairs cannot thus be regarded as an breeding on peatlands there, none of important component of the peatland the UBS/MBS plots in that district bird fauna in Caithness and Sutherland. contained skuas. Arctic skua Black-headed gull Arctic skuas, with a boreal-high arctic Black-headed gulls are breeding distribution, have long bred on the summer visitors to the area, but peatlands (Everett 1982) and, although passage migrants and winter visitors numbers have never been large, are a also occur. The species is common and significant component of the moorland widespread, although there is no good bird fauna. Yeates (1948) drew attention information available on total population to the occurrence of small colonies of size for the tvvo districts. Black-headed breeding arctic skuas, particularly in gulls breed mainly on water-bodies Caithness. There has been little where there is floating vegetation or documentation of numbers, however, where there are islands separated from until fairly recently. Everett(l982) the land. Thus breeding sites are Tecorded 20 pairs in 1969-70 and 28 somewhat irregularly distributed, pairs in 197 4 in thorough surveys of the depending on the physical nature of whole of Caithness. These totals are particular lochs. markedly le$s than the minimum A total of 15 pairs was recorded 47 breeding on one site in Sutherland Herring gull and great black-backed and four pairs bred on a site in gull Caithness. Birds were present at Herring gulls are a common resident 16 other sites throughout the species in Caithness and Sutherland, peatlands. but their breeding distribution is mainly coastal. Birds were recorded from four Common gull (of 58) sites, but these were presumably Common gulls breed throughout either migrants, non-breeding Caithness and Sutherland; they are wanderers or visitors from the coast. mainly summer visitors, but some Like herring gulls, great may be resident throughout the year. black-backed gulls have a coastal Elsewhere they have a northern breeding distribution and, although continental-low arctic distribution. they were recorded from 18 (of 58) sites, There are no good data on the overall there was no evidence of breeding at population size, but, on the basis of the any of these. The status of birds seen breeding distribution shown in The was probably similar to that of herring aUas ofbreeding birds in Britain and gulls observed inland. Ireland (Sharrock 1976) and average colony size. some 4,000(or10% of the Common and arctic terns British population) probably breed Both these species have a within Caithness and Sutherland. predominantly coastal breeding Breeding takes place in a variety of distribution, though there are some habitats, including moorland, bog, inland colonies of common terns, islets, rocky shores of lochs and shingle usually associated with the larger lochs. banks alongside larger water-bodies. Amongst these colonies Laybourne, There is thus abundant suitable habitat Manson & Collett (1977) have found within the peatlands. arctic terns nesting, and this species Common gulls were recorded has also been found at a small dubh breeding on six (of 59) sites, which lochan within quaking Sphagnum bog. held between two and 20 pairs each. The lochs were some 16-20 km from the Birds were present at 16 further coast. and arctic terns were not seen to sites, whilst there was no evidence feed inland (Laybourne, Manson & of breeding, they were probably Collett 1977). Common terns were seen nesting just outside the surveyed during NCC surveys at one site, and sites. arctic terns were seen on two In neither case was there any evidence of Lesser black-backed gull breeding. Lesser black-backed gulls are breeding summer visitors to Caithness Cuckoo and Sutherland, though some also As elsewhere, cuckoos are breeding occur as passage migrants. Their summer visitors to Caithness and breeding distribution is mainly Sutherland, particularly parasitising the 1.,,uc1.,,c,1, but some also occur inland. nests of meadow pipits. There is little The species was recorded on 11 (of 58) available information on numbers, survey sites, but there was no evidence although the species occurs widely of breeding at any of these. Former through the peatlands. It was recorded breeding colonies of this gull, as present on only two sites, but the with smaller numbers of the next two survey techniques used are unlikely to species, were mentioned as occurring have reflected accurately the true in the flow country by Harvie-Brown abundance of this species. & Buckley (1887). They were said to be heavily persecuted and have Skylark evidently declined considerably since Skylarks breed commonly throughout that time. the peatlands of Caithness and Sutherland and, after meadow pipits, are the commonest passerine 48 on these blanket bogs. Although a few requires fast-flowing water. birds are probably resident, the Pied wagtails are more common than species is mainly a summer visitor to grey wagtails, being widespread in the north of Scotland. both Caithness and Sutherland. Out of Skylarks were recorded breeding on 57 sites, one or two pairs were found on all the survey sites. However, because each of 10 sites and birds were present of the abundance of this it has on 17 further sites. White wagtails are always been difficult to passage migrants through the area in breeding densities. Counts vary from considerable numbers. Occasional an average of 210 birds recorded on pairs breed, usually hybridising with visits to a site in Sutherland to only one pied wagtails. singing male recorded from another site in the extreme north-west of Dipper Sutherland. Skylarks tend to be Dippers are resident water birds with a commoner in more grass-dominated widespread distribution in Caithness areas which occur over shallow peat or and Sutherland determined by the mineralised soils. presence of suitable streams for breeding and feeding. Numbers are Meadow pipit unknown, but one or two pairs were The meadow pipit is a common and found on each of five sites (out of 57) and widespread breeding bird throughout birds were present on 12 further sites. the peatlands of Caithness and In mid-Wales, the population of Sutherland and is probably the dippers has been the subject of intense commonest breeding passerine. autecological study (Ormerod 1985; Numbers of passage migrants and also Ormerod, Boilstone & Tyler 1985; some winter visitors use the region, Ormerod, Tyler & Lewis 1985; Tyler & whilst the breeding birds winter mainly Ormerod 1985). In particular, the factors in the Iberian peninsula. The small affecting distribution and abundance number of birds that winter in have been closely investigated. In a Caithness and Sutherland, mainly on detailed study of the influence of coast, are probably immigrants stream acidity on breeding distribution. rather than locally breeding birds. Ormerod, Tyler & Lewis (1986) have Meadow pipits were found breeding shown that breeding density is reduced on all sites surveyed, but, as with on those stretches of river which have sky larks, precise breeding numbers raised acidity. This is probably caused hard to The highest by the effect that raised acidity has in average count was of 249 per visit to a lowering the of freshwater site in Sutherland. Greatest numbers invertebrate prey. In areas of highly occur in heather-dominated areas, in acid rocks and soils, which have low contrast to the skylark. buffering capacity, coniferous afforestation has been shown to Grey and pied wagtails increase the acidity of run-off. Both grey and pied wagtails were found Ormerod, Tyler & Lewis (1985) stated on the sites surveyed. Grey wagtails are that all the streams which showed breeding summer visitors to the evidence of an historical fall in pH peatlands, wintering in England, drained from catchments which were Ireland and France. Whilst fairly 25-40% covered by mature forests; none WKiespre!aa in south-east Sutherland, had breeding dippers within 8 km of its they are scarcer elsewhere on the source in 1982. blanket bogs of the two districts. Out of The Welsh studies suggest that, if 60 sites, a pair was found breeding on coniferous afforestation of the one site in Caithness, whilst birds were peatlands of Caithness and Sutherland nr~><>i:::ont on two other sites. Many of the resulted in significant increase in watershed mire systems, with little stream acidity, dippers would one of water movement, are probably the first water birds to be seriously unsuitable for this species, which affected. 49 Other passerines surveys on 20 further sites out of 57. The Whilst not commonly thought of as birds species is common and widespread, of peatlands, wrens were found on 11 % especially in west Sutherland, though of 54 survey sites. Wrens are resident in scarcer in Caithness. Caithness and Sutherland, though the buntings are widespread in severity of some winters, to which the Caithness but scarcer in Sutherland. species is sensitive, means that One or two pairs were found breeding numbers are never great. One to three on each of two (of 67) sites. pairs were found nesting on each of five sites and birds were on a Conclusions further site. 3.8 The sample surveys, covering about Whinchats are breeding summer one-fifth of the Caithness and visitors in the peatlands and are Sutherland peatlands, have established widespread, although scarcer in that the region contains particularly Caithness than in Sutherland. Out of 60 large and diverse moorland breeding sites, three pairs were recorded bird populations. While the breeding nesting on one site in Sutherland and densities of some species such as birds were present on two further sites. golden plover, curlew, red grouse and Wheatears occur in Caithness and merlin are appreciably lower than in Sutherland both as breeding summer some moorland areas further south, the visitors and as passage migrants from total species list for these peatlands Iceland and Greenland. They are with their associated open water widespread and common on the habitats greatly exceeds that peatlands, usually nesting where there southern moorlands. huge extent of are outcrops of rocks and dry these peatlands also results in large grassland. One to seven pairs nested on total populations for many species. of 17 (out of 41) sites and birds Earlier records of breeding birds for were present on 19 further sites. the region are mostly unquantified, so Ring ouzels are widespread in most of that comparisons are hardly Sutherland, but they are scarcer in appropriate. The subjective easternmost Sutherland and Caithness. impression, however, is that these Five pairs nested on one site, one pair peatlands have changed little, if at all, in on another, and birds were on their most notable ornithological two further survey sites out total of features since this interest was first 57. The species requires steeply discovered over a century ago. Some of sloping ground and was thus absent the inland nesting colonies of gulls have from most of the sites surveyed for certainly decreased or disappeared, waders, particularly those dominated and golden plovers may no longer by watershed mire formations. reach the high densities reported from Sedge warblers are widespread in Strathmore around 1920. Certain suitable habitat in Caithness, though species may have had minor scarcer in Sutherland. A pair was found fluctuations but retained an overall nesting at one site and birds were status hardly differing from one decade present at five further sites out of 54. to the next. The few rarities may be new After meadow pipits and skylarks, colonists responding to more hooded crows were the most commonly favourable climate since 1955, or they recorded passerines on survey plots, may simply have been found through being seen on 70% of57 sites. Single the much greater ornithological interest pairs bred on three sites and birds in the region in recent years. were present on 37 others. The species It therefore seems quite to is resident and widespread throughout regard the recent advent of large-scale the two with hybrid afforestation as a quite unprecedented hooded/carrion crows occurring environmental change in its potential locally. for impact on peatland bird A single pair of ravens bred on one populations. site, and birds were recorded during 50 Figure3.3 Breeding dens1t1es(pairs/km;:) of wader species on 77 peatland sites m Caithness and Sutherland. ln each histogram the left-hand column shows the number of sites on which the species was not recorded 30 20 10 0 OA 0.8 1.2 16 2.0 24 2.8 3.2 3.6 4.0 4.4 4.8 5.2 + Density (pairs/km) Figure 3 3b Dunlm 30 20 10 Density (pairs/km) Figure 3 3c Greenshank 40 30 20 IO i:::=:=l 0 01 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 LO L2' 1.3 1.4 + Density (pairs/km) 51 Frequency Figure 3.3d Curlew 40 30 20 lO I I Fl F==I 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 !.! 1.2 1.3 l.4 + Density (pairs/km') Figure 3.3e Common sandpiper 40 30 20 LO F====l I ········! 0 O.l 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 LO Ll l.2 l.3' l.4 + Density (pairs/km') Figure 3.3f Snipe 60 50 20 10 I • . . F====l 0 0.1 0.2 0.3 0.4 0.5 1.0 1.1 l.2 1.3 l.4 + Density (pairs/km') 52 Frequency Figure 3.3g Lapwing son60 JOU F===I 0 0.1 0.8 0.9 + Density (pairs/km') Figure 3.3h Redshank 70 . . . 0.6 0.7 0.8 LO LI L2' 1.3 L4 + Density (pairs/km') Figure 3.3i Ringed plover 70 1·········1 0.4 0.5 0.6 0.7 0.8 u l'.3 !'.4 + Density (pairs/km') 53 figure 3.3J Oystercatcher 80 t J I J l t I I 0 0.4 0.5 0.6 0.7 0.8 0.9 l.O l.l 12 L3 L4 + Density (pairs/km) Figure3.4 Breeding distributions of mne bird species in !Okm grid squares throughout Ca ithness and Sutherland. From Sharrock (1976). with additional informal!on for the three wader species from the surveys m this report e Dehmte breeclmg e Probable breeclmg .Possible breeding 54 figure 3.4b Dunlin Figure 3.4c Greenshank Figure 3.4d Wigeon • Defmne breed mg •Probable breedmg •Possible breedmg 55 Figure 3. 4e Common scot er Figure 3.4f Hen harrier Figure 3.4g Golden eagle • Deflrnte breecimg • Probabh:: breechrn:; •Possible brei:::chrKJ 56 Flgure 3. 4h Merim Figure 3.4i Peregrine 9 Defm11e breedmg @Probable breed mg •Possible breedm9 57 / Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H Overall distribution and numbers of peatland birds in Caithness and Suft1erland Introduction quality of the unsurveyed areas; 4.1 Only about one-fifth of the peatlands of o to examine the further possibility of the region have been surveyed in detail associations between by the standard method described in br1ae<:im,a densities and map the Appendix. Yet the 77 plots attributes to estimate the total bird surveyed, covering 51,929 ha (Table 4.1: populations found in each habitat 19% of the remaining area suitable for category and in the total peatland · breeding waders), required 433 area: separate visits during 22 man-summers o to enable pre-afforestation maps to be of fieldwork over the period 1979-1986. used to assess the previous There are obviously considerable ornithological quality ofland now logistical and financial constraints to afforested and, from this, to surveying the remaining 81 % of the the reductions in populations, on the peatlands to the same standard. same principle as that used for Moreover, when afforestation is estimating the present populations. occurring so rapidly and on such a wide and haphazard geographical Wader densities and habitat scale, we cannot afford to await such 4.2 characteristics completion and must find a more rapid Background considerations yet reliable means of assessing the The possibility of making such unsurveyed areas. interpolations will necessarily be This chapter accordingly has four limited to those which have a aJms: virtually continuous distribution over o to find out if there are consistent the whole peatland area and are relationships between breeding bird sufficiently numerous. There is also uc.u"'"'""""' and habitat features obvious merit in applying such an recognisable on standard Ordnance approach especially to species with Survey maps; high conservation value. In practice the o to use any such associations, in study has been limited at present to the combination with information on such three most abundant, characteristic habitat features derived from the and important wading birds of the maps, to predict the ornithological peatlands, the golden plover, dunlin Table 4.1 Land-use and ornithological survey in Caithness and Sutherland Category as Category Area(ha) percentage of land area Total area of Caithness and Sutherland 764,094 !00% Ancient, semi-natural and long-established woodland 12,204 1.60% Forestry plantations 73.046 9·56% 'Improved' agricultural land and human settlements 104.090 13·62% Fresh water (minimum area) 25,170 3·29% Land too steep/high for moorland waders (including some high-altitude 279,484 36·58% blanket bog) and coastal areas Remaining area of blanket bog currently suitable as breeding habitat for 270,100 35·35% moorland waders* UBS/MBS 51,929 6·80% *The area of peatland recorded as suitable habitat for breedingwadersdoesnot equate to the full extent of blanket bog. There are considerable areas of steep, high-altitude blanket bog that are not considered suitable breeding habitat. 59 and greenshank. however, show only certain physical Reed (1985) and Reed & Langslow (in features of these peatlands (e.g. dubh press) have previously used Upland lochans, pool complexes and probable Bird Survey data to correlate breeding wetness as reflected by contouring). densities of waders with certain Waders also respond to vegetational landform characteristics identifiable features(Table 4.2). many of which are from 1:25,000 Ordnance Survey maps closely determined by physical (Table 4.2). Using these statistically structure, so that, for example, the derived relationships, it is possible to presence of bog pools determines the assess the likely of waders on presence of associated pool-side plant unsurveyed sites by measuring the communities. However, other extent of these landform features from vegetation is not linked with physical maps. For example, golden plovers, this way: a site otherwise dunlins and greenshanks were all expected to have a favoured mix of found to prefer 'flow' bog with pool habitats may be too frequently burnt complexes. High greenshank numbers heavily grazed or otherwise modified. are usually found where these pools Such operations can markedly are widely but regularly spaced over influence the vegetation, yet are not large areas. Drier and steep moorlands apparent until the site is actually visited. are poorly used by all species, and sites Thus, although assessments of close to conifer plantations hold lower peatland quality for waders from map numbers than would otherwise be evidence alone are possible if the expected (Stroud & Reed 1986). habitat requirements of the species The 1:25,000 Ordnance Survey maps, concerned are known and if the Table 4.2 Habitat preferences of breeding waders on moorlands in Sutherland from Reed & Langslow(in press). See section 3.4 for explanation of greenshank habitat use. Habitat nroJor,,n,...,o.,, all the summer activities during the breeding season and include habitats selected and young-rearing potentia I. The surveys did not aim locate nests; they have their most visible locations. often at or near feeding Golden plover Dunlin Greenshank Curlew Snipe Reds hank Key: + preferred avoided • no obvious trend 60 associations between habitats and strongly related to the distribution of physical features shown on maps are lochs and dubh lochans within blanket understood (Campbell 1985), there are bog and because these features are risks that such assessments may be especially easy to recognise from faulty because of various management maps. Mean densities of dunlins also practices which degrade otherwise differed between classes of sites CF.rn = 'good' sites. 6·28; p 61 Category A: Pool complexes and wet Sphagnum flows. These areas have a characteristicaUy high density of bog pools which are attractive to breeding waders and waterfowl. Loch Syre area, Sutherland, July 1986 Category B: Sloping blanket bog with individual pools. This drier type of blanket bog covers large areas of Caithness and Sutherland. Ben Hutig area. Sutherland, April 1986 62 Category C: Steeper and more broken ground. This landfonn is often broken by underlying bedrock protruding from the blanket peat and has generally low densities ofbreedingwaders. lnchnadamph National Nature Reserve, Sutherland, July 1983 Category D: Montane and other unsuitable areas. Fell-fields such as these are unsuitable as habitat for moorland breeding waders 63 Table 4.3 Features used in categorisation of the Caithness and Sutherland peatlands into four landforms for estimation of breeding wader populations. Landforms were assessed from 1:26,000 maps Category Dubh lochans Sueams Lochs Topography Gradients A: High density oi pools F-a\v streams. with Scanered larqer lochs. Flat. open and Genlly s!opmqto Pool complexes and dubh locbans none issuinu from usually with efently obviously fiat w!!h very lo·.v and wet clustered in obvious pool v:aters.hed mire curved edges boggy. Sphagnum-dominated than in the work in these steep moorland and previous category, and the surface rocky areas, sample plots generally vegetation is often eroded into gullies, excluded such areas, and it does not either naturally or by overgrazing or form part of the analysis. after severe fires, exposing areas of bare peat, which may be extensive. A test ofthe landform/wader Category C is that of steeper and associations more broken ground. Here the Sites surveyed by the NCC and RSPB gradients are steeper, with no teams were randomly assigned to one substantial areas of pools or dubh of two groups. One group of sites (the lochans. The ground is often highly control set) was examined by someone eroded, with few, if any, wet Sphagnum familiar with most of the and the dominated areas. Rocky outcrops and survey results. Each site was divided dry features are abundant. into landform categories according to Podsolic and gley soils with shallow Table 4.3, and the area of each peat surface horizons prevail, rather category within each site measured to than true blanket peat The vegetation the nearest l ha. A very few sites (four tends to have 1hchophorum out of 38) showed such diversity of cespitosum, Molin.ia caerulea or Calluna landforms in a small area that such vulgaris dominant and is of the type division was not possible and these characterised as 'wet heath' or, in the were not considered further. driest situations, acidic dwarf shrub The category oflandform on heath. each site was then singled out and the Category D is the steepest ground, numbers of golden plovers, dunlins and with screes, outcrops, crags, high greenshanks th?lt had been found by montane watersheds and summits with survey teams within that area were fell-field and shallow montane blanket assigned to it. These numbers were bog. This was considered to be then expressed as densities for each unsuitable habitat for most moorland species within that landform category. waders. Because of the very low wader In a few instances, where a site densities found during preliminary contained roughly equal areas of two 64 landforms, it was possible to calculate greenshanks at all. In category C, 90% densities for both landforrn types on the of areas held none. Because of the same survey site. similarity in the distribution of Figure 4.2 shows the distributions of greenshank densities in categories B densities of the three main wader and C, these two categories were species with respect to landforrn combined for this species. Whereas categories A, Band C. After densities 78°/o ofB and C areas combined held no had been obtained from the control set greenshanks, only 28% of A areas held of sites, the data were logarithmically none. Greenshanks show more amnormea (log (x + 1)), in view of the complicated habitat selection than the skewed nature of the density previous two species (section 3.4): they distributions (see section 3.4). for need running or standing open water calculation of means and standard for feeding, but they can nest at some deviations, which are given back- distance, either on hummock bog or on and often morainic ground on The categorisation oflandforms moderate slopes. provided overlapping but clearly If information from maps provides a different distributions of wader sound basis for estimating densities of rlo1n<: 65 Figure 4.1 Relationships between predicted and observed densities of three Figure 4. la Golden plover wader species on 24 sites in Sutherland (1982-1984) Pairs/km: 4.2 36 3.2 e I!) 2.8 e 0 2.4 0 2.0 El 0 e e 0 e 16 a Cl! 12 e 0 e 0 G e e 08 e 04 low medium high Figure 4. lb Dunlm f'igure4. le Greenshank Pairs/km: Pairs/km:· 3.2 LO 2.8 ee e 2A 06 o"' G 2.0 G 0 e e e L6 04 e e L2 Ill a e e 0.8 e 02 0 e e e o!O G e e llil e 0.4 e e e e e eeee low medium high low medium high 66 Frequency of sites Golden plover 4 2 I q::m ,q 0 4 5+ 2 Density (pairs/km ) Figure 4.2b Dunlin 12 10 8 6 4 2 IH 18.''. ~9 p I I 0 p I l 3 4 5+ 2 Density (pairs/km ) Figure 4.2c Greenshank 26 24 22 D Category A CategoryB 20 Iii Category C 18 16 14 12 Figure 4.2 Distribution of densities of breeding waders with to three of the landform 10 8 6 4 2 t q [j I a 2 2 2.l + Density (pairs/ km ) 67 causes. waders occurring on these blanket The correspondence of density bogs. distributions between the control and A set of 1:25,000 maps of the two test sets demonstrates that: districts was marked with the position o the categories of peatland cr'able 4.3) and extent of several land-use types - are real and reflect identifiable forestry, 'improved' agricultural land habitat types, and and human settlements - based on o it is possible to identify these information available in August 1985. categories on the basis of map Additionally, all major water-bodies evidence alone. were marked. Limited survey of steep This has important implications, since ground and high peatlands had it means that the quality of bird habitats previously shown that they contained of the whole area of blanket bog of very low densities of breeding waders Caithness and Suther land outside (see section 4.2). These could be survey sites can be assessed, as in the classed as unsuitable on the basis of following sections. their physical characteristics, and such areas also were indicated on the maps. The identification and mapping of It was assumed that the remaining areas 4.3 areas ofpeatland suitable for held breeding waders on the basis of breeding waders associations of wader distribution and Introduction mapped features. Many of the In order to estimate the breeding categorisations made in this mapping wader population of the two districts, a exercise were checked on the ground mapping exercise was carried out, first in 1986. Land-use categorisation from to measure the area of the main map evidence was found to be largely landforms and land-uses, secondly to accurate in areas checked on the assess the quality of the peatlands as a ground. After the maps had been habitat for breeding waders, and finally annotated, the area of each land-use to estimate the distribution and type within the two districts was abundance of the three main species of calculated. The extent of each type was Table 4.4 Comparisons between control and test data-sets as to means and variances in an investigation of the categorisation of land form types Data were transformed by log (x + 1) on both F and t tests. For greenshank. categories B and C have been combined for reasons given in the text Category A CategoryB CategoryC Golden plover l""' 2 128 F" = 2 342 F\,., 13 ·269 p>0·05 ·05 O·Ol Dunlin F,,, = 1·215 F\i:: l 083 F.;,; 2·760 p>O 05 p>0·05 p>O·OS l.;:; 0·283 !;7=0·368 l1, 0·136 p>0·05 p>O 05 p>O 05 Greenshank F:., IS= 3 074 F,,.~;.; = l·655 00l 68 estimated in units of 10 ha. A '·"·"''·.u"""~ have also been plantings close to method was used by Angus (1987) when roads to act as snow barriers and calculating peatland extent in the same windbreaks. The areas afforestable in region. the short and medium terms further Details of forest extent and ownership "''""'"'"'"'',....,the total of 79,350 ha, which were updated to January 1986 from not include a considerable area of information made available by the land owned by forestry interests for Forestry Commission. All woodland which grant-aid has not yet been was measured. In addition, NCC 's sought. inventories of ancient, semi-natural and long-established woodland Distribution of woodland Caithness and Sutherland (Walker 1985, In Caithness there is little semi-natural 1986), which distinguish between these woodland (Walker 1986). The total area and more recent plantings, were of ancient, semi-natural woods and consulted. long-established plantations amounts to only 677 ha in the whole district. Most of Results - current extent of habitats in these woods are found in sheltered Caithness and Sutherland glens or coastal gorges. Sutherland is The total mapped area for both districts more naturally wooded, with a total of came to 792, 390 ha. This compares with 11,527 ha of ancient, semi-natural and local government figures of 586,518 ha long-established woodland. In west and for Sutherland and 177,676 ha for central Sutherland there are many Gai.tnness, totalling 764,094 ha (Table small, semi-natural woodlands, and 4.1). Thus the mapping discrepancy is there are larger, more extensive woods 3 · 7%. Most of this occurred in the in the south of the district (Walker 1985). delineation of boundaries in the Forest technology has only recently intertidal zone. This is one of the types of allowed the draining and ploughing of land unsuitable for breeding waders, so heavy, water-saturated peat (Thompson the total for such land has been 1979, 1984). Thus it can be confidently corrected accordingly. The natural assumed that very few long-established habitats unsuitable for moorland plantations were planted on peatlands. waders are unevenly distributed across Such woodlands have a history of the being found largely in the several hundred years and would have mountainous west of Sutherland. The been established or developed on total extent of blanket bog is greater mineral soils. Figure 4.3 shows recent than that of moorland suitable for plantations to be concentrated in west breeding waders. The rest of the Caithness and east Sutherland and on peatland complex nevertheless the peatlands around Loch Shin and contains other habitats species of Lairg. conservation importance. The area of 'improved' agricultural Past and current extent of peatlands in land and settlements is 104,090 ha. This Caithness and Sutherland is a broad category, including areas of The 1:25,000 mapping allowed the improved hill pasture as well as better calculation not only of the total area and arable land in Caithness. It is distribution of flat, wet peatland suitable concentrated in north-eastern for moorland waders but also of the Caithness, with marginal crofting land extent of peatlands before forestry on the coasts and in some of the larger resulted in major losses of blanket bog. Sutherland straths. Study of the underlying landforms Within Caithness and Sutherland at shows nearly all recent forests to have least 79,350 ha were either already been established on peat. Within the planted or programmed for two districts there has been relatively afforestation by January 1986. The total little recent conversion of moorland to extent is slightly greater, as several agricultural use, although this has been small areas on some estates and fanns more significant in the distant past. have been planted as shelter-belts and Including newly afforested land, it is 69 Figure 4.3 Extent of recent forestry plantations in Cmthness and Sutherland in each !Okm grid square (January 1986) • 35D0ha+ l000- • 1499ha 3000- 3499ha • 500- • 999ha • 2600 2999ha l- 499ha • 2000- 2499ha o zero • 1500- l999ha Figure 4.4 Estimated extent of original peatland cover suitable as habitat for moorland breeding waders before afforestation • 700Dha+ 2000 • 2999ha • 6000- 6999ha !ODO • l999ha • 5000- 6999ha 1 _ 999 ha • 4000- 4999ha o zero • 3000- 3999ha Figure 4.5 Extent of peatland suitable as breeding habitat for waders in Caithness and Sutherland (January !986) 7000ha+ 2000 2999ha • 6000- 6999ha 1000- • • 1999ha 5000 • 5999ha l- 999ha 4000- 4999ha • 0 zero 3000- • 3999ha 70 Figure 4.6 The relationship between the estimated area of original peatland cover and the area of recent forestry plantations. Grid squares with substantial areas of sea and agricultural land are excluded Areas of recent forestry plantations (ha) per lOkm grid square. 4000 3000 2000 1000 ••• ~ 2000 4000 6000 8000 10000 Estimated area of original peatland cover (ha) per IOkm grid square. calculated that formerly the total area of The total original area of blanket bog peatland suitable as habitat for in Caithness and Sutherland has been breeding waders (categories A, Band calculated as about 401,375 ha (Lindsay C) was about 343,000 ha. By August 1985 et al. in prep.). This contrasts with the this area had fallen to some 270,100 ha. area of 343,000 ha calculated as However, the loss of peatland to forestry originally suitable for waders, has not been uniform over the whole indicating that there is a considerable region. There has been a much greater area of steeper mountainside with proportional loss of the lower-altitude shallow or dissected peatland (below 250 m) peatlands in north-east unsuitable for waders (included in Sutherland and west Caithness (Angus category D). 1987). Figure 4.5 shows the present 71 distribution of peatland suitable for The use oflandforms to estimate breeding waders. Comparison of the 4.4 abundance and losses ofwaders distribution of forestry plantations on pea.tlands (Figure 4.3) with that of the original Estimation of wader population sizes peatland extent (Figure 4.4) shows that The total area suitable for breeding virtually all recent plantings have been waders was divided into three of the on peatland suitable for waders. Areas four landform categories outlined in unsuitable for moorland waders have section 4.2 and Table 4.3. Golden been little planted. To the west of the plovers, dunlins and greenshanks do Moine Thrust (Figure 1.3) there is a not breed in every 10 km square in large area of land less favoured by Caithness and Sutherland (Figure moorland waders (see section 2.3). The 3.4a-c) despite the presence of same features (rockiness, steepness, apparently suitable habitat, but they fragmentation and, in places, high occur on most peatland areas. The altitude) also make it largely unsuitable mean densities found in each of the for the establishment of forests. To the three landform categories takes such east, the area of unsuitable land non-uniformity into account by diminishes and, correspondingly, the including sites which appear suitable extent of forestry plantations increases. on habitat grounds but where .,,_,_,,_,.,c,., There is a strongly significant positive are either absent or breed at correlation between the area of original anomalously low densities. Inclusion of peatland cover and the area of forest such sites will reflect the scarcity or plantations in each 10 km grid square non-occurrence ofpeatland waders in a (r = 0·691, n = 41, p 72 Table 4.5 Estimated breeding populations of moorland waders on the Caithness and Sutherland peatlands based on associations of densities with landformcategories See Table 4.3 for definitions of the landfonn categories. Extent(km:?) Density Estimated Rounded total (pairs/km2) numbers(pairs) numbers (pairs) Golden plover LandformA 828·5 2·37 1963 LandformB 992·8 l ·46 1449 LandformC 880· l 0·64 563 Dunlin LandformA 828 s 3·90 3231 LandformB 992·8 0·57 5til6 LandformC 880· l 0·04 35 Greenshank LandformA 828·5 0·64 530 LandformB 992·8 0·08 79 LandformC 880· l 0·02 !8 630 eroded peatlands where there is an agreement with the extensive wet areas even spacing of small hags and hillocks. of peatland (Figure 4.S). This species is The highest densities coincide with the thus one which would be directly and area of greatest forestry expansion significantly affected by loss of further (Figure 4.3), thus giving a potential for peatland habitat in Caithness and further severe losses if afforestation of Sutherland. peatland habitat continues at its current rate. Greenshank A total of 630 pairs of greenshanks Dunlin is estimated to breed in Caithness A total of 3,830 pairs of dunlins is and Sutherland on landform categories estimated to breed in Caithness and A, B and G The total British breeding Sutherland. This estimate is higher than population is currently estimated at those made previously for the same 960, with most of the remainder being area owing to a reanalysis of data using in Ross and only small numbers different methods (see the Appendix breeding elsewhere (Sharrock: 1976). for details). This reanalysis gives a more Thus Caithness and Sutherland realistic total for the two districts. hold about 66% of the British (and Adjusting the data collated for Piersma therefore the European Communities') (1986) by incorporating this figure gives breeding population of this species a national total of 9,900 Thus (Table 8.1). Caithness and Sutherland hold about The breeding distribution of the 39% of the British breeding population greenshank throughout Caithness of dunlins and 35% of the European and Sutherland is shown in Figure Communities' breeding population 3.4c. Although it is widespread in the (Table 8.1). The methods used to survey extreme west of Sutherland (D. & M. for dunlins usually result in Nethersole-Thompson 1979), the underestimates of true numbers, but habitat here is fragmented and this will apply generally so that relative discontinuous because of interruption proportions will be correct. by unsuitable high mountains. In The highest breeding densities in Caithness and east Sutherland the Caithness and Sutherland show close breeding habitat is much more 73 Figure 4.7 Extent and quality of habitat for Key breeding moorland waders on the Caithness and Sutherland shown Category A: Pool complexes and wet as the land form categories of Table 4.3 Sphagnum flows Category B: Sloping blanket bog with pools Category C: Steeper and more broken ground D Category D: Montane and other unsuitable areas 74 continuous. Greenshanks avoid the redshank), and are evidently agriculturally modified land in the north widespread but elusive merlin and and east of Caithness and are strongly short-eared owl). The rarest species, associated with peatlands throughout especially of waders, are extremely both districts. difficult to find, and in such a large area In a review of birds potentially it is unlikely that all breeding pairs have affected by afforestation published by been discovered. The 77 surveyed sites the Royal Forestry Society, Harris (1983) may give a reasonable sample from categorised the greenshank as which the total numbers of some of breeding usually on intractable, wet these other species could be estimated boggy open spaces above the planting within broad limits, but there is no limit; this is totally incorrect and means yet of testing such an misleading. In Caithness and assumption. Sutherland, as elsewhere, a high proportion of the total British population 4.6 Summary of the ornithological is directly at threat from further loss of interest peatland habitat. The outstanding features ot the ornithological interest of the Caithness Losses ofbreeding wade:rS and Sutherland peatlands are the high In the same way that habital/density species diversity and the large associations have been used to populations of breeding waders. No calculate the numbers of breeding fewer than 15 species of waders are waders currently present on the known to nest in the region and these Caithness and Sutherland peatlands, include 66%1, 39% and 18% of the total the losses of breeding waders due to British breeding populations of the afforestation of peatland are greenshank, dunlin and golden plover estimated in Chapter 6. respectively. There is a wider ecological of breeding birds, The numbers of other peatland including waterfowl, raptors and 4.5 breeding birds passerines, than for any other moorland The previous section has shown that it is area in Britain. Important fractions of the possible to estimate numbers of golden total British breeding populations of plover, dunlin and greenshank based other species are as follows: on characteristic with red-throated diver(l4%), black certain habitat and landform types. For throated diver (20%), greylag goose the other peatland birds there are (wild stock 43%1), wigeon (20%), varying difficulties in estimating total common seater (39%), hen harrier (5%), . . . common scoter (16%), hen harrier (1 %), merlin(4%), goldenplover(l7%), dunlin (35%), greenshank (66%), arctic skua (2%) and short-eared owl (4%). Several species have declined and/or are still declining elsewhere in Britain - wigeon, buzzard, golden eagle, merlin, red grouse, golden plover, dunlin, snipe, curlew, greenshank, red-necked phalarope and raven. Some of these have already been reduced in numbers through afforestation in other districts as well as in Caithness and Sutherland. Many of the above species are mainly or wholly northern European (boreal arctic) in distribution and depend in the rest of their range on naturally treeless open wetlands and tundras. Britain supports the southernmost populations of these birds because of the large extent of open moorland resembling these more northern habitats. Caithness and Sutherland are an especially favourable area for this bird assemblage because the conjunction of climate and topography have given large areas of wet blanket bog, with a wide variety of associated open water habitats which simulate tundra. Some of the characteristic breeding birds of northern tundra are different, however, the goose tribe being represented in Caithness and Sutherland only by the greylag and the whimbrel being replaced by the curlew, so that the precise combination of species is not exactly replicated anywhere else in the world. In the winter the region remains important for several scarce or local bird species. The peatlands are used as feeding habitat and roosting sites by internationally significant numbers of Greenland white-fronted geese. Golden eagles and hen harriers stay to hunt the moors, and the red grouse population is resident. 76 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H Unsurveyed habitats and species groups 5.1 Lochans, lochs and rivers (1986), Graesser (1979) and others have The study of open water habitats in demonstrated the close relationship Caithness and Sutherland for their between declines in salmon catches botanical and invertebrate interest is and the afforestation of upland only just beginning. Most of the catchments used as nursery streams. standing open waters belong to the dystrophic or oligotrophictypes, but 5.2 Invertebrates little is known of their limnology at Because of the remoteness of the region present. Caithness and Sutl'lerland hold the terrestrial invertebrate fauna is very important freshwater fisheries: such little known and more survey work is as the Hehnsdale, Shin, Thurso needed to identify the range of species and N aver have long been famous for and record their abundance and the exceptional quality of their salmon. distribution. Because of their The streams and larger moorland lochs geographical position, it is likely that the are also fished a good deal for brown peatlands of Caithness and Sutherland trout. Whilst recent in catches support distinctive invertebrate on the Helmsdale and other rivers have communities differing in precise been, in part, attributed to offshore species composition from those found netting, Egglishaw, Gardiner& Foster on peatlands further south in Britain. Top left; Emperor moth Bottom left: N orthem eggar moth Top right: Large heath butterfly (northern form) Bottom right: Fox moth 77 They contain the most extensive population of the large heath butterfly Coenonympha tulha in Britain, essentially a peatland species, and large day-flying moths such as the emperor Satumia pavonia, northern eggar Lasiocampa callunae and fox Macrothylacia rubi are numerous. The available evidence suggests that the lochs and pools within the peatlands support assemblages of freshwater invertebrates of conservation importance, including some species which are nationally rare. The arctic alpine dragonfly Aeshna caerulea is known from the region and the recent discovery here of the water beetle Oreodytes alpinus, new to Britain and found elsewhere only in Siberia and the extreme north ofEurope, suggests northern tundra affinities in the invertebrate as well as the ornithological fauna (Foster & Spirit 1986). Other nationally rare water beetles occur in the dubh lochans (Spirit 1986; Foster 1987). 78 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H Effects of afforestation on the ecosystem The Nature Conservancy Council's birds displaced from planted ground report Nature conservation and are permanently absorbed by afforestation in Britain (1986) gave a adjoining unplanted peatland, giving general account of the impact of an increase in population density there. afforestation on both the biological and Any lasting absorption of displaced the physical environment. Ratcliffe birds would be contrary to all that has (1986) has also considered the effects on been learned about the relationships wildlife in upland Scotland. These between the carrying capacity of commentaries are relevant to the moorland and population densities of Caithness and Sutherland peatlands, breeding birds. Results from one site in but the following statement makes more Sutherland surveyed before the specific reference to the effects on this afforestation of adjacent moorland particular area, and especially on its showed that numbers of some waders birds. The impact of afforestation is increased major planting but complex, for not only are there obvious decn:as;ed in subsequent years to and direct effects on the ground densities below the original levels. This ploughed and planted, but unplanted indicates that, whilst birds were initially ground and freshwater habitats both displaced from ploughed areas and within and beyond the forest are attempted to breed dose by, the affected in varying degrees. In the population failed to maintain itself at this situation of continually expanding larger Although some species are afforestation, open ground steadily subject to marked annual fluctuations, contracts in area and may become many are relatively constant, and all increasingly surrounded and have an upper limit imposed by the 'squeezed' between blocks of forest, so productivity of the habitat. Most of the that its relative value may ~ ..- ... ~~. peatland bird species already have a non-breeding surplus which is Effects on birds excluded from nesting by the territorial 6.1 The direct effect of afforestation is to behaviour and spacing of the breeding replace the peatland bird assemblage population. with a woodland bird assemblage. Thompson, Thompson & Nethersole Different are affected at Thompson (1986) found that, during varying rates: some, such as dunlin, years of high greenshank breeding disappear quickly, while others may density, egg weight was less and linger for several years, though usually interactions between females more in reduced numbers (Reed 1982a). The frequent (both factors militating against relevant outcome is that, by the time the breeding performance) than when young fore st closes to the thicket stage density was low. They concluded that at 10-15 years, the habitat has been "loss of habitat surrounding lochs and transformed and is useless to most open rivers used by feeding greenshanks moorland birds. They disappear and, at will inevitably promote competition, the minimum, their loss is directly increased predation, reduced food proportional to the area and quality of intake and, ultimately, the production of ground planted. The problem is less viable eggs (through birds laying exacerbated because the flows are later and lighter clutches)". During their particularly attractive to forestry movement from nest to feeding interests because oflow land prices areas, greenshank chicks (like other and the relative ease and cheapness of wader young) are at considerable risk planting operations on such flat and from being trapped within the deep unbroken ground. These flat flows are drainage ditches and plough-lines also the prime peatlands for both (Vaisanen & Rauhala 1983). Nethersole vegetation and breeding birds. There Thompson & Watson (197 4) have has thus been a selective conversion of documented the decline and extinction many areas of the highest quality bird of groups of breeding greenshanks habitat to forest which required extensive open areas It is exceedingly unlike! y that the within the mature pine forests 79 ofStrathspey. When these were planted moorland still remained, it was and dense cover grew up, the surrounded by large expanses of greenshanks deserted the area (see well-established forest: the dunlins had section 3 .3). disappeared and the golden plovers There are, indeed, indications that had declined to low density (A. D. afforestation leads to a thinning-out of Watson pers. comm.). breeding bird populations on adjoining Preliminary studies from moorland unplanted moorland beyond the forest bird surveys in Caithness and boundary or forming enclaves within it. Sutherland and also northern England For some species, this is only to be suggest that some breeding species expected. There is typically a cessation tend to avoid the forest edge, so that of moor-burning on ground adjoining there is a zone oflower density on the forest, and in some areas grazing is moorland around the perimeter reduced as well through removal of (Langslow 1983; Stroud & Reed 1986). sheep. This leads to an increase in Such an effect could be partly the result luxuriance and age of vegetation, and of habitat change, but it could also be a after about ten years the effect is often response to increased predation quite marked, to the point where associated with the forest In suitability as breeding habitat has Kincardine, R. Parr (pers. comm.) found declined for those species which need that afforestation of half of Ker loch Moor short vegetation, for example golden was followed not only by a substantial plover and dunlin. As an example, in decline in the breeding population of Galloway scattered pairs of dunlins and golden plovers but also by a marked a relatively dense population of golden increase in n8st predation for the plovers bred during 1950.SO on the residual breeders on the remaining moorlands between Airie and moorland. Grobdale, east of Loch Skerrow. By Afforestation creates new nesting 1986, although some 20 km~ of open habitat for carrion and hooded crows Afforestation results in both the direct loss of patterned bogs and less obvious, long-term effects. The loss of such wetland areas has seriously affected internationally important moorland breeding wader populations. Loch More wetlands, Caithness 80 (Petty 1985) and much increased cover open moorland hunting area than that for foxes (Hewson & Leitch 1983). These which will satisfy the feeding and other predators are provided with secure requirements of their prey species. refuges by the forest, for in thicket In areas of low carrying capacity, plantations their breeding places are each pair of golden eagles may need to usually impossible to locate; yet both hunt over open moorland averaging rely largely on ground outside the 10,000 ha in area. In Galloway, the forest for food and will perforce reduced breeding performance of concentrate their search over the out of four pairs of golden eagles adjoining bogland. Until recently many was correlated with an average 43% parts of these peatlands, especially the afforestation of their feeding areas by remoter areas, were subject to only a 1979 (and an average 69% of the more low nest predation pressure from productive ground below 905 m). One crows, for large areas were devoid of pair, which subsequently disappeared, their nesting sites (in trees) and were had lost 62% of their feeding area and distant from the nearest breeding pairs. 90% of their low ground (Marquiss, Though crows range widely over the Ratcliffe & Roxburgh 1986). open moorlands, the advent oflarge Afforestation also accounted for most of blocks of forest in numerous places is the 66% decline in the raven breeding bound to their penetration of population between 1946-60 and the remaining open ground. The effects 197 4-76 in southern Scotland and could be even more serious for the northern England reported by other waterfowl than for the waders and Marquiss, Newton & Ratcliffe (1978). other species, since the vicinity oflochs Raven decline here has continued in and rivers is a focus for their nests and parallel with further planting, reaching the young are taken there soon after 72% by 1981 (Mearns 1983). In some hatching and so are readily located by parts of these regions the decrease has predators. been proportional to the area These suggestive pointers have led to afforested, but some raven territories more detailed research, now in hand, have been deserted even when they on potential avoidance and predation are only partly planted. In Galloway responses which could represent a again, a hill population of buzzards serious 'edge-effect' of afforestation, in numbering at least 25 pairs in 1946-65 addition to its primary impact in causing had declined to only two pairs in 1981 species loss. These effects may not (D. A. Ratcliffe unpublished; Mearns appear until the plantations are 1983): although only about 50% of the well-grown, and they may become area had been afforested, a much enhanced as the overall balance of higher proportion of the more areas and pattern of configuration productive low ground had been lost. between fore st and peatland change The ability of ravens and through the advance of further new h11~n::i1rrl"' in mid-Wales to maintain their planting. In a study of birds of enclosed numbers in the face of afforestation areas of moorland surrounded by appears to depend on the exceptionally conifer forests in southern Scotland, good food supply of the remaining open Rankin & Taylor (1985) concluded that ground in this area and the less the size of such areas and the number continuous distribution of blocks of or diversity of habitats within the forest (Newton, Davis & Davis 1982). moorland 'islands' together had a Forest edges have provided tree nest dominant influence on the numbers and sites for a few additional pairs of ravens densities of breeding bird species. and buzzards in parts of Wales where Only areas greater than 270 ha both tree and rock sites were otherwise sustained a representative moorland lacking. However, for these species bird assemblage including less other moorland raptors such as merlin common species such as merlin, ring and kestrel which may utilise old crows' ouzel and short-eared owl. The nests within the new forests, the crucial predatory birds need a much larger issue is the extent of open hunting 81 ground remaining beyond the the overall numbers of breeding plantations, since the new forests have waders on existing moorland (see little or no value as feeding habitat. Chapter 4) can also be used to Open ground remaining within estimate the losses of these on areas forests as rides and roadside verges is recently afforested. The areas of recent virtually useless as nesting habitat to planting and land released for planting nearly all the birds of the Caithness and were superimposed on earlier, Sutherland peatlands. The nests of pre-afforestation Ordnance Survey larger species would be far too readily maps, and the quality oflost peatland located by predators (Ratcliffe 1986), habitats according to the four Apart from occasional pairs of small landform categories of Table 4.3. It was passerines, these areas are devoid of then calculated that 912 pairs of golden nesting birds. Common sandpipers plovers, 791 pairs of dunlins and 130 may continue to nest on stream banks pairs of greenshanks once used where the forest edge is kept well back. moorland occupied or planned to be but most waders need a broader occupied by plantations (Figure 1.4). On expanse of nesting habitat Even where this basis, the original, pre-afforestation patches of pool and hummock 'flow' are populations for the Caithness and left unplanted within the forests, they Sutherland peatlands of Figure 1.2 can can be of only doubtful value to be calculated to have been 4,900 pairs breeding waders and other waterfowl. of golden plovers, 4,620 pairs of dunlins Mostly they are too few and too small, and 760 pairs of greenshanks. There and habitat changes resulting from the has thus been an actual or predictable abruptly abutting forests are probable loss of 19% of golden plovers, 17% of (Chapman & Rose 1986). dunlins and 17% of greenshanks as a direct effect of afforestation. It has not 6.2 Losses of peatland birds been possible yet to estimate the losses The methods used to estimate the of other breeding bird species, but quality of breeding habitat and hence most of those listed in Table 6.1 can be Table 6.1 Declines in bird species due to afforestat\on in other parts ofBritain (Sources: Marquiss et al. 1978, 1985; Mearns 1983: Nature Council 1986; D. A. Ratcliffe pers. comm.) Species Area Wigeon Ettrick District Greenshank Valley Dunlin Wales, Cheviots, Southern Uplands of Scotland (at least 400 pairs lost) Wales, North York Moors. Cheviots, Southern Uplands. Eastern Highlands (at least 2,000 pairs lost) Curlew Wales, Northern England, Southern Uplands. Highlands (several thousand pairs lost) Snipe Wales, Northern England.Southern Uplands, Highlands (no estimate) Red grouse Wales, Northern England, Southern Uplands, Highlands (no estimate, but must be thousands of pairs lost) Golden eagle Southern Uplands, West Highlands(l5-20pairs lost) Merlin Wales, Northern England, Southern Uplands, Highlands (lens of pairs lost) Buzzard South-west Scotland (c. 25 pairs lost) Raven Cheviots. Southern Uplands. South-west Highlands(tensofpairs lost) ln addition. species such as lapwing, redshank, curlew, snipe. whinchat and stonechat have declined m the lowlands through agricultural development. so that their upland populations are now increasingly important 82 presumed to have been affected. makes it even less likely that there will Some of the Caithness and be any significant return of the waders Sutherland peatland birds which occur regarded as so important in this area. widely in the British uplands have Observation of open areas created by already lost a good deal of ground large-scale death of young trees from elsewhere, through the widespread pine beauty moth attacks does not afforestation of their habitats on both suggest that anything approaching the blanket bog and drier moorland (Table peatland bird community redevelops. 6.1). The national populations of golden plover, dunlin, curlew, red grouse and The lack of compensatory gain in merlin have all been significantly 6.3 forest birds reduced by this transformation of Nature conservation and afforestation in habitat These losses elsewhere are Britain (Nature Conservancy Council almost certain to continue through still 1986) examined in depth and rejected further afforestation, so that the the arguments that afforestation Caithness and Sutherland populations replaces moorland by a woodland of affected species will become an habitat with a richer bird fauna and th~t increasing proportion of the British it restores a more original type of totals - unless afforestation continues habitat to a man-made landscape. here, too, at the present rate. A main conclusion of this report is as The pre-thicket stage after follows (p. 64): afforestation is beneficial to some birds "When the heaths, grasslands, which nest in fairly dense cover, peatlands or sand dunes that are lost to including some open moorland species afforestation have special nature such as short-eared owl, hen harrier conservation value in their previous black grouse. This phase is state, the forests that replace them, ephemeral and 'once-off', however, and however good they may become for cannot influence the long-term wildlife, are not, and never can an assessment of impacts. The crucial adequate substitute. This is so because question is whether the cycle of return they can never contain more than a to open ground, when the forest is fragmentary; depleted and therefore harvested and before the next inadequate representation of the open generation of trees again closes to ground habitats, communities, species thicket can restore a sufficiently large and physical features in their •vuu...... and close approximation to the original wholeness'.' peatland bird community. Given that Afforestation has a particularly the forest rotation will, in the longer destructive effect on wet ground term, maintain a certain proportion of habitats. The forests that are created pre-thicket ground at any one time, are quite different from natural boreal foresters have argued that it will coniferous forest; not only are they continue to maintain a parallel almost wholly composed of exotic representation of moorland birds species, but their structure and lack of (eg.Garfitt 1983} subsidiary vegetation layers are highly As a general thesis, this argument artificial and will remain so. Whatever has been found wanting (Nature opportunities may exist for diversifying Conservancy Council 1986: Ratcliffe conifer plantations on fertile, lowland 1986): the original bird community is not sites in more southem they are restored, and there is a shift to a mixed minimal in Caithness and Sutherland, type in which some of the original where most plantations will remain species return, but less numerously unthinned until they are felled because than those of open woodland, scrub or of the very high risks of wind-throw. The forest edge and glade. While it will be still more important point, however, is some time before the situation on the that the blanket bog covering so much Caithness and Sutherland peatlands of the region is a naturally treeless can be properly observed, the effect of ~.,,., .• '"".,,_vegetation developed under the afforestation in drying out the ground extremely oceanic climate and that 83 Mature conifer forests are dense and dark. These even-aged plantations lack the structural diversity found in natural woodlands. The forest birds encouraged by such plantations do not compensate for the loss of the moorland birds displaced forest of any kind on the flows is an been created is quite sufficient to give artefact (see section 2.2). de facto representation to this It has been claimed by forestry viewpoint: with any more, the balance interests that afforestation in Caithness sheet oflosses compared to gains and Sutherland is beneficial to the becomes increasingly adverse and conservation of birds because: unacceptable. Even if rarer songbirds o it increases the numbers of such as crossbill, redwing, fieldfare individuals, or even of species, and brambling colonise the forest, compared with those living on the there is more than enough of such peatland habitats; habitat already and this does not o it enhances overall diversity, giving provide an argument for further forest the best of both worlds, since some expansion. It has to be remembered unplanted peatlands will still remain. that, for some peatland and moorland These arguments are invalid. The birds, this is not the only region where bulk of the resulting forest bird fauna contraction and loss are occurring consists of small passerine songbirds through afforestation. which are common throughout Britain, many of them in hedgerows and even in suburban gardens (Table 6.2). Their occurrence in greater numbers than the displaced birds of the peatlands is irrelevant to the conservation issue. By the same token, the additional "diversity" created through limited afforestation is of little account if the bird community which is added has low intrinsic conservation value The amount offore st which has already 84 Table 6.2 Bird species found in coniferous plantations in Caithness and Sutherland Species National population National population estimates (pairs) Species estimates(pairs) Buzzard 8,000-10,000 Goldcrest 500,000 Kestrel 30,000-40,000 Spotted flycatcher 300,000 Woodcock 8,000-35,000 Long-tailed tit 200,000 Tawny owl 50,000-100,000 Coal tit 500,000 Wren 3,000,000-5,000,000 Blue lit 3,500,000 Dunnock 2,000,000 Great tit 2,000,000 Robin 3,800,000 Treecreeper 200,000-300,000 Redstart 140,000 Carrion/hooded crow l,000,000 Whinchat 18,000-30,000 Starling 3,000,000-6,000,000 Blackbird 4,600,000-5,000,000 Chaffinch 5,000,000 Song thrush 1,500,000 Greenfinch 800,000 Mistle thrush 300,000 Siskin 15,000-30,000 Sedge warbler 200,000 Scottish crossbill SOD Willow warbler 2,500,000 Reed bunting 400,000 6.4 Effects on vegetation Ratcliffe (1986) has given reasons for Afforestation causes the replacement of regarding the vegetation of linear open peatland vegetation by dense stands of habitats such as rides, roads and conifers with few other plants. During streamsides as a particularly the pre-thicket stages some of the fragmentary, uncharacteristic and existing species, especially grasses, unsatisfactory representation of the some sedges and dwarf shrubs, range of open moorland communities. become more luxuriant and tussocky. This is even more the case for peatlands The deep ploughing and draining used because of the pronounced drying as standard ground preparation rapidly effects which result The only residual dry out the surface of the intervening open habitats worth considering in this peat ridges and cause a loss of the context are wider areas, mainly strongly moisture-loving species. When patches of pool and hummock flow, left the forest doses to thicket, virtually all unplanted within the forests. The the ground vegetation disappears, questions to be asked about these are because the shade is so intense and the whether they are a sufficient litter fall so heavy. In these unthinned representation of the peatland forests this condition will persist until ecosystem and whether they will retain clear-fell harvesting, and this is a main their previous character in the longer reason why they can never be term. regarded as equivalent to natural Many of the true boreal forests boreal forests. The vegetational interest elsewhere naturally contain open areas of these new plantations is thus limited of bog too wet for trees to grow on. They to whatever ground is left unplanted range in size from tiny pockets to huge and whatever cover redevelops during expanses, but most of them result from pre-thicket phases of subsequent rotations. underlying topography and soil which 85 Figure 6.1 Diagrammatic representation of natural Scandinavian forest bog and afforestation blanket bog in Scotland to illustrate the significant differences. Whilst underlying topography may be similar, blanket bog swathes the mineral substrate, contrasting Wlth isolated basins of peat in Scandinavia. Forest bog trees are of mixed age and size, and waterlogging on the bogs causes a transition, with increasingly stunted trees around the edges of the The open structure of these forests reflects their ecological maturity. Plantations in Caithness and Sutherland consist of dense, uniform trees of even age which fragment once continuous blanket bog and cannot be thinned to achieve a more 'natural' state owing lo the severe risks of wind·throw Scandinavia: dry climate, with raised bogs developed only where topography maintains a high water-table and with forest on dry mineral soils and bog margins Scotland: wet climate, with blanket bog developed i:>w•rvw11,,,.rp except on steep ground and with plantations established on ploughing and draining have lowered the water-table 86 give impeded drainage. Most of these the ditch. The Irthinghead Mires, a Site forest bogs are accordingly classified of Special Scientific Interest in either as valley mires and fens or as Northumberland, are a series of small bogs. Others are types not found but important bogs protected from in Britain such as aapa mires and palsa direct afforestation but now totally mires. Where the ground slopes surrounded by the Kielder Forest. steeply into wetter places, there may be Charman (1986) has correlated the a clear-cut edge between forest and decreased plant diversity on these bog, but more typically there is a remnant bog sites with increasing age gradual transition in which the trees thin of surrounding forestry and has out and become stunted. appearing speculated that this is aresult of a falling finally as an irregular perimeter of water-table, though fertiliser or spray dwarf 'checked' growth on the bog drift may also be involved. edges where the water-table is Oneofthesebogs, CoomRiggMoss. critically high. Some bogs have a became totally surrounded by conifer scattering of these checked trees thinly plantations in the 1960s and 1960s. Since distributed over much of the surface, that time there have been marked and but others have a central treeless area. major changes to the flora and structure Natural forest bogs show enormous of this peat b9g, and, whilst the precise variety in their relationship to the mechanisms are not yet clear, "it is surrounding forests (see, e.g., Moen extremely unlikely that the changes 1986; Eurola & Holappa 1986). seen at Caom Rigg would have taken Enclaves of wet flow within plantations place if the surrounding area had not may in time develop a superficial been afforested" (Chapman & Rose similarity to these natural forest bogs. 1986). If the full conservation interest of In many cases there will be a hard, ombrotrophic mire systems is to be wall-like edge to the trees, but natural preserved, complete hydrological regeneration may in time produce a systems need to be protected intact. In more graded edge. The main point to the northern flow country, such note is that, because the Caithness and hydrological systems can be extensive, Sutherland examples are blanket bog, because of the breadth of watersheds the leaving of arbitrary unplanted and the extent of catchments. 'islands' of flow will not approximate to The implications are of a high any natural conditions, for their probability that isolated portions of flow relationships with the surrounding body left within planted forest will lose their of peat are lost (Figure 6.1). While the ecological and botanical interest pool and hummock systems may be of through inevitable consequent change. outstanding interest, their development The remaining possibility, that has depended on the growth of peat peatland vegetation will regenerate to over a wider surrounding area. This its previous state during successive situation also makes residual 'islands' of clearance phases in the future forest flow vulnerable to further changes rotations, seems very unlikely. The likely to reduce or destroy their deep-ploughing and draining required remaining interest. for afforestation cause a permanent Even limited drainage can have drying of the affected bog surfaces very serious effects on the ecology {Pyatt 1987). Water-table and surface of blanket and raised (Ivanov flow patterns are immediately 1981; Lindsay 1987). Not only can disrupted (McDonald 1973; Robinson limited surface drainage such as 1986) and these changes are followed moor-gripping affect the level of the by longer-term shrinkage of peat water-table and the composition of the {Prus-Chacinski 1962), wastage and surface vegetation (Lindsay in prep.), oxidation (Silvola 1986). As the but peripheral deep drainage can alter trees become established, higher the ground-water 'mound' (Ingram evapo-transpiration rates lower the 1982), resulting in a lowering of the bog water-table further, contributing to a surface at considerable distances from complete change in soil structure and 87 in ground flora. So when the forest is surfaces are likely to become eventually felled, the habitat will dominant, and the probability is that a never revert to its previous state, for mixed grass-heath will develop widely. the physical conditions are It is noticeable that in areas opened up permanently altered. Even .if there is through pine beauty moth 'kills', a great regeneration from buried seed or abundance of purple moor-grass recolonisation from outside, the ground Molinia caerulea and rosebay becomes too dry ever to support again willow herb Chamerion angustifolium the moisture-loving plants which has rapidly developed, evidently in characterised the previous blanket response to the high nutrient levels from bogs. Species associated with dry peat added fertiliser. Patterns of afforestation have caused the isolation and fragmentation of previously extensive bog systems. The vegetation of such isolated areas will slowly change owing to altered management practices and the 'edge-effects' ofthe new plantations. Forsinard, Sutherland 88 Finally, the deep-ploughing and 1987). Run-off and stream sedimentation progressive modification of the upper can be reduced by modifying the peat after afforestation (including system of draining, but on deep peat erosion and redistribution of material) this is difficult because the whole renders the affected areas worthless purpose of draining is to lower water for studies of vegetational, climatic and tables by removing more water than land-use history through pollen before. Recent research on the blanket analysis. The sub-fossil poll.en and other bog plateau of Llanbrynmair Moors in plant remains which allow such Wales has shown that the historical reconstructions and implementation of management correlations (Godwin 1975) have to exist guidelines on water protection has in an undisturbed state, free from any failed to prevent an increase in stream suspicion of modification to the sediment loads to 246°/o of former complete peat profiles within which values in one catchment and to 479% of they are buried and preserved. Surface former values in another, after forestry oxidation destroys the upper layers of ploughing (Francis 1987). the record, while any redistribution of Drying of acidic peat increases its material confuses it hopelessly. acidity by oxidation (Pearsall 1938; Cracking of peat also allows material Silvola 1986). The acidification of stream from the surface to sink deeply below. waters by the 'scavenging' of While it may be that a sufficient number atmospheric acidity by surrounding of undisturbed profiles will survive in forest is now well known (e.g. Harriman unplanted sites within the region, the & Morrison 1982). While the prevailing precise needs for the location of sample acidic peats, soils and waters of sites within these palaeo-ecological Caithness and Sutherland are studies cannot be predicted and, quite vulnerable to enhanced acidification, often, fairly closely spaced samples the lower levels of atmospheric acidity along transects are needed. in this region (compared with, for example, Galloway) are likely to Effects on abiotic features moderate the degree to which such 6.5 Afforestation also has several quite acidification occurs (Fry & Cooke 1984). marked effects on the physical/chemical Data should nevertheless be collected environment, and these have been and the situation monitored. The other recently reviewed (Nature major chemical effect, of nutrient Conservancy Council 1986). There has enrichment of peats, soils and waters by so far been insufficient research to the addition of fertilisers to promote establish their relative importance forest growth, is potentially serious in its Caithness and Sutherland, but some biological implications. This can cause general extrapolations and predictions local eutrophication, leading to algal can be made. Ploughing on these blooms in lakes and reservoirs, and the peatlands has the immediate and same effect has been observed after inevitable consequence of increasing significant clear-felling of part of a the amplitude of peak stream flows by catchment (Parr 1984). shortening the duration of peak run-off; Studies of these changes and their after rain the excess water runs off biological effects are patchy and, in much more rapidly than before, and some cases, fragmentary, and there is a total water yield increases slightly particular dearth of information for (Robinson 1980). When the forest has Caithness and Sutherland. There is an closed to form thicket, there is a accumulating literature to show that, in decrease in water yield through one area or another, the effects of interception effects (Calder & Newson afforestation on freshwater fisheries are 1979). Erosion of peat and mineral soil is generally adverse. This subject was another inevitable result of ploughing reviewed in Nature conservation and (Robinson & Blyth 1982), and afforestation in Britain (based on subsequent cracking of deep peat is Graesser 1979; Harriman & Morrison reported (Pyatt & Craven 1979; Pyatt 1982; Stoner, Gee & Wade 1984; Stoner 89 & Gee 1985; Drakeford 1979, 1982). An overall assessment Egglishaw, Gardiner & Foster(l986) 6.6 Afforestation so fundamentally have since shown a high degree of cor transforms the peatland ecosystem that relation throughout Scotland between it is effectively destroyed. The fauna extent of afforestation and decline in and flora are lost and the physical salmon catches. Acidification oflakes in attributes so altered that, even if Sweden has affected water birds forestry ceased, any reconstitution of (Eriksson, Henrikson & Oscarson 1980; the previous ecosystem would be for all Eriksson 1984), and a decline in dippers practical purposes impossible. The has been correlated with enhanced pre-thicket stage of subsequent forest river acidification in Wales associated rotations can only be regarded as a with afforestation (Ormerod, Tyler & derisory restoration of the peatland Lewis 1985). These findings point to the ecosystem. In view of the importance of need for study of the chemistry of the the peatland ecosystem, its replacement Caithness and Sutherland peatlands. An by a type of forest which is artificial and important aspect of effects on abiotic present over increasingly large areas of features is that they are mostly not Britain, with little regional variation, confined to the ground actually planted, amounts to a substantial net loss of but have significant overspill effects into nature conservation interest. The adjacent areas, especially in the case of various possibilities of effects extending rivers and lakes. Afforestation therefore beyond the forest perimeter can only has to be assessed in its effect on the compound this loss. whole catchment. The rivers draining from the peatlands of Caithness and Sutherland support major salmon fisheries which are important to the local economy. Blanket afforestation has seriously affected such fisheries elsewhere 90 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H International implications The international importance of the .1 The 'Bem' Convention on the peatlands of Caithness and Sutherland ConservationofEwropean has to be considered in relation to Wildlife and Natwral Habitats overseas opinion and the requirements Article 3 of this Convention requires the which stem from international treaties promotion of "national policies for the concerning nature conservation to conservation of wild flora, wild fauna which the United Kingdom is a party. and natural habitats, with particular The Northern Highlands of Scotland, attention to endangered and vulnerable which include this area, were identified species .. , and endangered habitats". as globally important and listed as a Article 4 specifically concerns the "priority biogeographical province of conservation of habitats. Article 4(1) land the establishment of protected states that "appropriate and necessary areas" in the World Conservation measures [shall be taken] to ensure the Strategy (IUCN/UNEP/WWF 1980), a conservation of the habitats of the wild document welcomed by the UK flora and fauna species, especially Government. This lays great stress on those listed in the Appendices I and II, the conservation of non-renewable and the conservation of endangered resources, the preservation of genetic natural habitats". Article 4(2) states: diversity and the maintenance of "The Contracting Parties in their essential ecological processes and planning and development policies ecosystems. All these considerations shall have regard to the conservation are pertinent to the continued survival requirements of the areas protected of peatlands in Caithness and under the preceding paragraph, so as Sutherland. Indeed, the UK non to avoid or minimise as far as possible governmental response to the World any deterioration of such areas:' Article Conservation Strategy (World Wildlife 4(3) requires the special protection of Fund-UK et al. 1983) suggests that the areas important to breeding migratory results of upland bird surveys show that species. ·'forestry operations should be planned These provisions are applicable to with great care''. the peatlands of Caithness and In September 1986 the International Sutherland. Their status as an Mire Conservation Group (1MCG) endangered and important natural visited the peatlands of Caithness and habitat has been recognised by the Sutherland on a study tour. This group International Union for Conservation of of peatland ecologists from nine Nature and Natural Resources countries considered the blanket bogs (IUCN/UNEP/WWF 1980), Royal of the north ofScotland to be "unique Society for the Protection of Birds (1985), and of global importance", expressed IMCG (1986), NCC (1986 and this its "dismay at the extent to which report), Ramblers' Association afforestation was found to be destroying (Tompkins 1986), Scottish Wildlife Trust this internationally important habitat" (1987), Council for the Protection of and viewed ''the speed of destruction Rural England (Stewart 1987) and with particular alarm" (International others. Many of the species listed in Mire Conservation Group 1986). Appendices I and II of the Convention The United Kingdom is a signatory to occur on these peatlands. These four international treaties which are include otter, black-throated diver, relevant to the conservation of peatland red-throated diver, little grebe, merlin, habitats the 'Bern' Convention, the peregrine, ringed plover, wood 'Ramsar' Convention, the EEC Directive sandpiper, common sandpiper, on the Conservation of Wild Birds and Temminck's stint, dunlin, red-necked the World Heritage Convention. phalarope, short-eared owl, pied wagtail, grey wagtail, wren, whinchat and stonechat. 91 The 'Ramsar' Convention on or 7.2 Wetlands oflntemational b. is of special value for maintaining the Importance especially as genetic and ecological diversity of a Waterfowl Habitat region because of the quality and The United Kingdom is al.so a party to peculiarities of its flora and fauna the 1971 'Ramsar' Convention, having or signed it in 1973 and ratified it in 1976. c. is of special value as the habitat of The preamble to this Convention, which plants or animals at a critical stage of specifically includes peatlands, their biological cycles indicates that the Contracting Parties or are "convinced that wetlands constitute d. is of special value for its endemic a resource of great economic, cultural, plant or animal species or scientific and recreational value, the communities. loss of which would be irreparable" 3. Criteria for assessing the value of and that they desire "to stem the representative or unique wetlands. progressive encroachment on and loss A wetland should be considered of wetlands now and in the future". internationally important ifit is a Article 3(1) of the Convention requires particularly good example of a that "the contracting Parties shall specific type of wetland formulate and implement their planning characteristic of its region:' so as to promote the conservation of the wetlands included in the list [of The Caithness and Sutherland protected sites], and as far as possible peatlands are quite exceptional in the wise use of wetlands in their meeting all eight of these criteria. territory". The Confere nee of the Contracting Criterion la: The peatlands of Parties held in Cagliari, Italy, in 1980 Caithness and Sutherland regularly agreed eight criteria for the assessment support more than 20 ,000 waders. of international importance of wetlands. A wetland should be considered Criterion lb: The peatlands support at internationally important if it met any of least 1% of the individuals in these criteria. The relevant text says: biogeographical populations of the "l. Quantitative criteria for identifying following waterfowl: Greenland wetlands of importance to waterfowl. white-fronted goose, native greylag A wetland should be considered goose, dunlin and golden plover. internationally important if it: a. regularly supports either 10,000 Criterion le: The peatlands support at ducks, geese and swans; or 10,000 least I% of the breeding pairs of the coots; or 20,000 waders following biogeographical ,..,...,,., ...... ,'"' .... ~'"'"' or of waterfowl: native greylag goose, b. regularly supports 1% of the dunlin and golden plover. individuals in a population of one species or subspecies of waterfowl Criterion 2a: The peatlands support an or appreciable number of individuals of c. regularly supports 1% of the several rare, vulnerable or endangered breeding pairs in a population of one species or subspecies of plants and species or subspecies of waterfowl. animals. Among the species or 2. General criteria for identifying subspecies in this category are: black wetlands of importance to plants or throated diver, Greenland white animals. A wetland should be fronted goose, greenshank, wood considered internationally important sandpiper, merlin and golden if it: a. supports an appreciable number of a Criterion 2b: The ecological rare, vulnerable or endangered peculiarities of the peatland fauna and species or subspecies of plant or flora have been described in this animal report. The peatlands dearly qualify 92 under this criterion. c. species considered rare because of small populations or restricted local Criterion 2c: As breeding and distribution; wintering habitat for large numbers of other species requiring particular specialised peatland birds, insects and attention for reasons of the specific plants, the peatlands fulfil this criterion. nature of their habitat. Trends and variations in Criterion 2d: The peatlands qualify population levels shall be taken into under this criterion since some of their account as a background for plant communities and their breeding evaluations. bird assemblage are globally unique. Member States shall classify in particular the most suitable Criterion 3: The global importance of territories in number and size as the area as an outstanding example of special protection areas for the oceanic blanket bog has been conservation of these species, taking recognised by such groups as the into account their protection International Mire Conservation Group requirements in the geographical (see above). This area is a supreme sea and land area where this example of blanket bog development. Directive applies. 2. Member States shall take similar Contracting Parties to the 'Ramsar' measures for regularly occurring Convention provide regular reports on migratory species not listed in Annex wetland conservation. The UK report to 1, bearing in mind their need for the Conference of the Contracting protection in the geographical sea Parties at Groningen, Holland, in 1984 and land area where this Directive stated: "Recent research has applies, as regards their breeding, suggested that mire systems are the moulting and wintering areas and most threatened wetland habitat in staging posts along their migration Britain" and "commercial afforestation routes. To this end, Member States is now a major threat to blanket mire shall pay particular attention to the systems, promoted by tax incentives protection of wetlands and rather than the direct economic value of particularly to wetlands of the timber produced" (IUCN 1984, international importance. p. 452). 3. Member States shall send the Commission all relevant information EEC Directive on the so that it may take appropriate 7.3 Conservation of Wild Birds initiatives with a view to the As a member of the the UK has co-ordination necessary to ensure accepted and is bound by Directive that the areas provided for in 79/409of2 April 1979. The Directive is paragraphs 1 and 2 above form a concerned with many aspects of bird coherent whole which meets the conservation, but Article 4 "''"'''"'"''i' protection requirements of these habitat protection is of particular species in the geographical sea and relevance to the peatlands of Caithness land area where this Directive and Sutherland. This says: applies. "l. The species mentioned in Annex 1 4. In respect of the protection areas shall be the subject of special referred to in paragraphs 1 and 2 conservation measures concerning above, Member States shall take their habitat in order to ensure their appropriate steps to avoid pollution survival and reproduction in their or deterioration of habitats or any area of distribution. disturbances affecting the birds, in so In this connection, account shall far as these would be significant betaken of: having regard to the objectives of this a. species in danger of extinction; Article. Outside these protection areas, b. species vulnerable to specific Member States shall also strive to avoid changes in their habitat; pollution or deterioration of habitats'.' 93 The following species listed under natural sites or precisely delineated Annex l, and thus requiring habitat natural areas of outstanding universal protection under Article 4(1), occur on value from the point of view of science, the peatlands of Caithness and conservation or natural beauty:' Sutherland as either breeding or wintering species or subspecies: The peatlands of Caithness and black-throated diver, red-throated Sutherland meet all three criteria, and diver, Greenland white-fronted goose, IUCN, which is responsible for vetting hen harrier, golden eagle. peregrine, ''natural site" World Heritage merlin, golden plover, wood sandpiper, submissions for Unesco and the World red-necked phalarope and short-eared Heritage Bureau and making owl. Most of the remainder of the recommendations for the World breeding bird species, especially the Heritage List, has recently urged the waders, are migratory and require Nature Conservancy Council to habitat protection under Article 4(2). consider nominating the peatlands of Under Article 4(4) Member States are Caithness and Sutherland as the first required to strive to avoid pollution or British wetland listed under the World deterioration of habitats both inside and Heritage Convention. This Convention outside protected zones. This is recognises the concept of a ''common particularly relevant to the afforestation heritage" and that certain unique of peatlands since such afforestation "cultural and natural properties" results both in direct habitat loss constitute "a world heritage for whose {Chapter 6) and in pollution of protection it is the duty of the watercourses and other wider effects international community as a whole to (section 6.6). co-operate". 7. 4 Tbe Wol'ld ~eritage ~o:nvention The Convention concemmg the Protection of the World Cultural and Natural Heritage, or the World Heritage Convention, which the UK Government ratified in 1984, requires each State Party to ensure that "effective and active measures are taken for the protection, conservation and preservation of the cultural and natural heritage situated on its territory" which qualifies for World Heritage status under the Convention. The following are the criteria for "natural heritage": "natural features consisting of physical and biological formations or groups of such formations, which are of outstanding universal value from the aesthetic or scientific point of view; geological and physiographical formations and precisely delineated areas which constitute the habitat of threatened of animals and plants of outstanding universal value from the point of view of science or conservation; 94 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H Birds and bogs: their conservation needs The Caithness and Sutherland o Development of unusually diverse peatlands should be viewed as an systems of patterned surfaces on ecosystem in which the different blanket bog instead of on other types elements - of physical environment, of bog/mire where their analogues plants and animals - are a functionally occur elsewhere in the world. interdependent whole. Whilst these o A floristic composition of blanket bog elements are evaluated separately and and associated wet heath vegetation this report places special emphasis on unique in the world and representing the birds, overall nature conservation a highly Atlantic influence on plant value resides in this unity. The most distribution and vegetation significant aspects of nature development. conservation importance are as follows. o A tundra-type breeding bird assemblage showing general National value similarity to, but specific differences o The large area and diversity of from, that occurring on arc:nc- blanket bog as a physiographic/ subarctic tundras. vegetation feature and the relative o Significant fractions of the total lack of disturbance in many places, populations of certain breeding bird giving the greatest extent of actively species in Europe and particularly in growing mire in Britain and one of the the territories of the ._.,,.,.,.,r,.,,,,,,... few areas of extensive natural Communities (Table 8.1). terrestrial vegetation now remaining. o Insular ecological and other o The extensive development of adaptations by several bird species patterned flow as a feature rare in which may represent incipient British bogs elsewhere and the evolutionary divergence in Britain. ,,..,,.,..,,,,,,,..,,shown by pool hummock systems. The crucial question remaining is o The abundance of certain rare or about how much of the total peatland local bog plant species. area now left in Caithness and o The greater diversity of the breeding Sutherland deserves national and bird assemblage than that of moorland international conservation designation and bog elsewhere in Britain. or other conservation measures. Nature o The large total numbers of many bird conservation faces a new situation in the species, considered as percentages Caithness and Sutherland peatlands, in of their total British populations (Table that the distinction usually made 8.1) and bearing in mind that some of elsewhere between specially important these species are declining sites and the more diffused interest of elsewhere and will continue to do so, 'the wider countryside' breaks down especially as a result of afforestation. here. Over much ofBritain, especially o The presence of several nationally the lowlands, a great deal of the land rare breeding bird species. surface has been so modified by Man o The predicted equivalence of interest that nature conservation interest is now relating to habitats (mainly open thinly spread, so that remnants of semi waters) and groups (especially natural habitat are readily identifiable invertebrates) not surveyed. as specially important 'islands'. Even in upland areas where semi-natural International value habitat remains extensive, it may be of o One of the largest and most intact variable nature conservation interest, known areas of blanket bog (a so that selecting the best areas is still globally rare ecosystem-type) in the possible, though more difficult. On the world. Caithness and Sutherland peatlands, o A northern tundra-type ecosystem in any attempt to select the 'best' areas for a southern geographical and climatic conservation measures is much more location, by reason of the extreme problematical and less appropriate, oceanicity of the northern Scottish because: climate. o there are no abrupt differences or 95 Table 8.1 Population and distribution data for birds occurring on the peatlands of Caithness and Sutherland ,ff ·$ !!' -::-"' j ?J :!J Specias t Grey heron J,:Oo0·8.5DQ Greylag goose * c. 000600 43% S:att~r~d Wigeon * ao 3'JiJ.5GO 20·,; t .. b:;.;:,nt Teo! 3,5005,000 Wide;pr~od Mallard 40.00~' V¥1d·::::;pmad Ccmmonsc:oter * * 30+ 76-BO 39% c lOO{lr-olmidl Colden eye * >m Red·breastedmerqanser * l.GD0·2,GGD Honhi::mly Goo:sander + 90G·L3oo Hen harrier * * * S:::·'.i:HOt·.:!d Sparrowhawk Bu=rd Colden eagle * * S.:-~rnerEd ltestml Merlin * * * Peregrine * * * Red grouse Black grouse O;'Sterc•tc:her * Ringed plovm * '*' Colden plO'ier * * 3,950 22.61JO JS'• Lapwing ,500 Temminck'sstint * * * A.b/!:£:-n! Dun!in * + * 3.030 9,900 3a1•, Snipe * C, 500 + 22,€00 :r:'.. Woo Ruff * * * Curlew JS.ODO i:,~ Redslmnk 32,JQO Creenshank + * 53il 9'30 6El°'i'J J"\.b5ii;£H 96 Spocic:s Wood sandpiper Common sandpiper Red-nocl Arctic skua Black-hooded gull Common gull .. Orea! blaak-backed gull !.osser black·backed gull Short·eared owl .. * Skylark Meadow pi pi! * Grey wagtail Plod wagtail Dipper Whinchat Stonecha1 Wheal car Rlngou:.el Sodge warbler Hooded crow Twit<> rac:• 97 distinct boundaries in special interest ground beyond the forest edge: this within the peatland areas, other than extends over a wide zone, but the total those recently created by effect is not known. Aerial spreading of afforestation; fertilisers and pesticides is also likely to o within any one peatland area, the affect a peripheral zone ofunknown overall high level of special interest is width beyond the forest edge. reinforced by the mutual Ornithological site assessment has to interdependence of the different take account of the point that each bird habitat and species components of species occupies its own ecological the ecosystem; niche and that the total bird o the international importance of these assemblage thus requires all the peatlands resides especially in their different habitat components of the total extent and wildlife content. moorland ecosystem. While the pool These points will now be amplified, and hummock systems are especially first by considering the needs of the important for several feeding bog structure and vegetation and of the and nesting habitat requirements birds separately. usually diverge. Greenshanks feed at As regards the structural and pools, lochs and rivers but often nest on vegetational characteristics of these shallow peat or dry, stony moraines. peatlands, it is possible to identify Golden plovers, curlews, red grouse, undisturbed pool and hummock meadow pipits and skylarks nest in systems, level flows and associated fens large total numbers on the shallow peat as outstandingly important features. areas as well as on the wetter flows. cannot be considered in isolation Snipe and redshanks feed in the and have to be regarded as nuclei grassier and flushed areas. The within the whole moorland ecosystem interpolation procedures described which needs to be represented, and validated in section 4 .2 allow areas including the related wet and dry of high quality wader habitat to be heaths, flushes, lochs and streams. In identified, all appropriate for key site making any such selection of status. The distribution of these areas, representative areas, the complete with a necessary buffer zone of 1 km to range of variation in surface pattern allow for the effect of plantations both on structure and vegetation and in the adjacent peatland vegetation and botanical features illustrating on the moorland bird assemblage, is geographical, topographic and shown in Figure 8.3. altitudinal variation within the region The other waterfowl need lochs and also has to be included. The location rivers, and their numbers depend on and extent of these key peatland areas, the frequency and extent of these all of which qualify as "key sites" in the habitats. Most of the ducks and greylag termsofAnatureconservationreview geese nest on the moorland well back (Ratcliffe 1977b) are shown in Figure 8.1. from the edges of these open water The concept of delineating undisturbed habitats. The raptors, owls and catchments has to be expressed in the scavenging birds are widely dispersed selection process, but, because many over the whole area, each pair holding of the most important flows lie across a large territory and needing an broad and ill-defined watersheds, extensive hunting range (up to 10,000 ha boundaries drawn through the for a pair of golden eagles). Because of imaginary middle of watersheds the mobility of birds and their need to surrounding a particular catchment are range widely but variably, the drawing quite inappropriate: to protect these of boundaries through a continuous features they have to be drawn well peatland area becomes an even more within adjacent catchments. Extensive arbitrary and unsatisfactory process hydrological systems which have less than it does in trying to delineate than 6% cover of conifer plantations are representative sites for their structural shown in Figure 8.2. There is also the and vegetational interest. problem of the effect of afforestation on The possible 'edge-effects' from 98 Figure 8.1 Extent of key Key pea!land areas in and Sutherland mcluding associated hydrological units and rn Prov1s1onal key peatlands l km buffer zones 99 Figuxe8.2 Key sys!ems []]]] Key hydrological systems The shaded areas represent 23 individual systems which had less than 6% cover of conifer plantations in January 1986 100 Figure 8.3 Extent of high quality peatland Key wader habitat (categories A and B of Table 4.3) in Caiihness and Sutherland including High quality v1ader habitat associated lkm buffer zones 101 4 . atchments (includmg Key Figure 8. River c . l mportance for loch systems) of excepllona i black-throated divers 122 River catchments 102 Figure 8.5 Area containing significant Key known merlin nesting and feeding habitat and nesting sites of rare breeding waders ~Rare breeding birds habitat and common scoter up to 1986 (lOkm grid squares) 103 Figure 8.6 Combined representation of the Key provisional areas required to maintain aspects m Provistonal (mcluding of the exceptional nature conservation interest !iii! peatland with buffer zone in Caithness and Sutherland ~ High quality wader habitat with buffer zone ITIIJ Key systems squares holding rare breeding f?'::l River catchments of exceptional importance ~ for black·throated divers 104 Figuxe 8.7 Extent of blanket bog m Key Cail:hness and Sutherland, with areas of forestry (including land in Forestry Blanket bog Commission ownership or with Forest Grant Scheme approval) established on peatland Plantations on blanket bog and elsewhere 't:J Plantations on other substrates 105 encroaching forest also have worrying peatlands and that any one part of them portents for breeding birds, and some is of importance to several overlapping of them may not show until the interests. plantations are well established. Any Beyond this, however, the overriding avoidance effects are likely to be issue is that the concept of a overtaken in seriousness by increased representative series of exemplary nest predation from crows and sites is no longer accepted as an {see section 6.1). The effects of adequate recognition of the afforestation on hydrology, conservation value and needs of the sedimentation and water chemistry of Caithness and Sutherland peatlands. lochs and rivers, both within and This earlier approach does not match outside the planted ground, could also the present reassessment, based on have adverse implications for edge fuller survey information and the feeding waders, other waterfowl and international dimension. The riparian birds. It is important that outstanding international importance of complete large river catchments are these peatlands lies in total extent, protected from afforestation, continuity and diversity as mire forms acidification is known to be un... .cc'""'c:;u and vegetation complexes and in the by conifer plantations in base-poor total size and species composition of geological areas and adversely affects their bird populations. breeding water birds such as black The remaining extent of the throated divers and dippers (section Caithness and Sutherland peatlands as 6.5) and the economically important a whole should therefore be regarded populations of salmon and trout (section as the desirable nature conservation 5.1; see also Nature Conservancy area for its national and international Council 1986, pp. 40-41). Twelve key importance. A significant and river catchments each holding more important fraction of the total has than 2% of the population of black- already been lost to afforestation in an throated divers are shown in Figure 8.4. extremely arbitrary and haphazard Quite often, high ornithological interest way (Figure 8.7), and there is no rational and high vegetational interest do not scientific or conservation basis for coincide. The distribution of the rarer making a further arbitrary selection birds (Figure 8.5) and plants is erratic within the remainder, to surrender and uncorrelated. additional areas to afforestation. The These considerations underline the case for retaining as much as possible great difficulty in trying to delineate of what remains is reinforced by the arbitrary units of peatland which could extensive losses ofpeatlands and their satisfy the to represent wildlife resulting from afforestation in adequately the total field of variation other parts of Britain (Wales, the and to ensure that the units could be Cheviots, the Southern Uplands of individually viable and secure from Scotland and the Highlands and gradual loss of interest. For it has to be Islands) and by the fact that such losses assumed that most of the surrounding will continue elsewhere under a policy areas would be vulnerable to further which sets an open-ended annual afforestation, right up to the boundaries. planting of33,000ha. Jndeed, While there is a general correlation in under the present rules which promote quality between certain afforestation, all plantable areas of vegetational and ornithological blanket bog could eventually features, an attempt to select a disappear outside specially protected representative series of sites for the one areas. would by no means take adequate In the time that it has taken to collect account of the other. Figure 8.6 and analyse the data presented in this combines the areas required to report (1979-1986), habitat supporting maintain the features described above. nearly 19% of the specialised breeding It is clear that the exceptional interest is wader populations has been destroyed maintained throughout much of the and only eight of 41 hydrological 106 systems in and eastern land-use as effectively as it damages Sutherland have been left free of nature conservation interests. It thus afforestation. fallows that the simplest way of The maintenance of the nature achieving nature conservation over conservation interest over the the Caithness and Sutherland oeammc1s is largely compatible with the peatlands is to maintain existing traditional land-uses, which include land-uses, though with greater crofting, game management and regulation of moor-burning. Beyond fishing. In contrast to these traditional making this point, the present report uses of peatland areas, the drastic does not seek to discuss details of the change in land-use caused by possible conservation measures which afforestation is totally destructive to the might be adopted to ensure this natural and semi-natural habitats and outcome, nor is it concerned with the their nature conservation value. While questions that have been raised crofting, game management and nature concerning the economic and social conservation are not mutually exclusive, justification of such forestry (National blanket afforestation also forecloses Audit Office 1986). Its aim is to present future options on traditional forms of the conservation case. Dubh lochan systems,central Caithness 107 During recent years, a great deal of concern has been expressed over the past losses of natural and semi-natural habitat and its wildlife in Britain. Many of these losses took place during earlier periods before nature conservation was conceived - notably the destruction of the great forests and the fenlands before 1800 AD The post-1940 inroads into the coastlands, chalk grasslands, lowland heaths, moorlands. old hay meadows, marshes and hedges and the pollution of lakes and rivers mostly occurred in response to national need or before effective legislation and adequate knowledge existed. The area of the Caithness and Sutherland peatlands already lost to fores try - most of it since the passing of the Wildlife and Countryside Act 1981 represents perhaps the most massive single loss of important wildlife habitat since the Second World War. Henceforth the situation will be different, in that any further losses to this unique area will take place as the result of deliberate decisions taken in full knowledge of what is at 108 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H Acknowledgements The Upland Bird Survey was funded by on the distribution of rare bird species. the Nature Conservancy Council's Dr Derek Ratcliffe and Dr Des ChiefScientist Directorate (Project No. Thompson of NCC provided valuable 406). Work in 1985 and 1986 formed part additional information on the of NCC's Moorland Bird Study (Project distribution of waders and raptors in No. 433). We are most grateful to all the Caithness and Sutherland, and owners and occupiers of survey plots Margaret Palmer and Dr Ian McLean for permission to work on their land and gave helpful advice on freshwater and to their gamekeepers and agents invertebrate matters. local help and advice. Dr Judy Stroud helped with mapping We record our thanks to Dr Derek land-uses, Fiona Burd categorised Langslow for initiating the survey and to maps oflandforms, and earlier drafts of Fraser Symonds for developing the the report were read by I. S. Angus, techniques in the pilot years. Dr M. I. Avery, Dr I. Bainbridge, Dr G The fieldwork was undertaken by Bibby, Dr H.J. B. Birks, Dr L. Campbell, Dr Tim Reed, David Stroud, Fraser DrP.J. Dugan, DrN. Easterbee, DrP. R. Symonds, Chris McCarty, John Barrett, Evans, Dr A. D. Fox, Dr R. J. Fuller, Dr H. Catrina Barrett, Martin Moss, Kevin Galbraith, Dr M. W. Holdgate, Dr T. H. Shepherd and Phil Ball with assistance Keatinge, Dr A. N. Lance, Dr D.R. from Dr Derek Langslow. Work used to Langslow, R. G. Sou tar and Mrs B. W. test methodology for this programme Vittery. We are particularly grateful to was undertaken by NCC and RSPB staff Dr D. A. Ratcliffe, who made numerous including Robert Barton, Roger Buisson, and substantial contributions to the text. Dr Tony Fox, Pete Hack and Chris Special thanks are due to Kevin Thomas, with additional data from Shepherd, who carried out analyses, Peter Ferns and Roger Lovegrove. and particularly to Alison Rothwell, who Ian Mitchell kindly extracted gave great help in the production of this information on recent afforestation from report, proof-reading several drafts and the Forestry Commission's stock maps preparing most of the figures. in Inverness. We wish to acknowledge We should also like to express our the help given to the survey teams by deep gratitude to Sheila Beech, Karina NCC 's Regional Officer for North-West Brighton, Janet Holding and Maureen Scotland, Dr PeterTilbrook, and Sladden C:VVord Processor Operators at Assistant Regional Officers for Peterborough) typing many draft Caithness and Sutherland, Stuart versions of this report and struggling Angus, Lesley Cranna, Terry Keatinge successfully with the large tables, to and Kristin Scott. Their advice and Marina Palmer for aiding production, to assistance over the years in ironing out Barbara Brown.for clerical assistance, problems has been invaluable. and to Stuart Wallace, who helped in NCC's peatland surveys have been preparing maps and diagrams. undertaken by Fiona Burd, Mandy We thank Doric Computer Systems Camm, Dan Charman, Fiona for the help and expertise provided to Everingham, Sarah Garnett, Richard us during the production of the Lindsay, Sara Oldfield, Rachel O'Reilly, computer generated maps contained John Ratcliffe, John Riggall, Jane Smart, herein. The Arc/Info Computer David Stroud, Colin Wells and Sylvia Mapping/Graphic Information System White. Fiona Everingham also gave was used to process the many classes of help in drafting this report. data needed for the study and to We are grateful to RSPB and Dr Len generate the maps and analyses. Campbell for allowing us to use the Finally, we record our warmest results of their Caithness and thanks to Philip Oswald for editing the Sutherland survey of 1985 and other text for publication. unpublished data. Their survey was undertaken by M. J. Birkin and S. J. Hayhow. Roy Dennis and Dr Greg Mudge helpfully supplied information 109 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H References ANGUS, S. 1987. BYRNE, R. 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The impact ofland-use changes on golden eagles in the Sco/lish Highlands. Peterborough, Nature Conservancy Council (CSD Research Report No. 720) A., REED, T. M., & WILLIAMS, T. D 1983. The Hebrides did the observers record in the same vvay? Milder Study Group Bulletin, 39, 24-26. WORLD WILDLIFE FUND-UK et al. !983. The Conservation and Development Programme for the UK. A response lo the \!Vorld Consenralion London, GK. 1948. Bird haunts in northern Britain. London, Faber and Faber 118 Please note: the content of this PDF file is taken from archive holdings, and has been rendered to produce the best possible output. However, you may experience fluctuations in quality due to these files not being created from electronic originals Nature Conservancy Council Birds, bogs and forestry The peatlands of Caithness and Sutherland David A Stroud, T.M. Reed M.W. Pienkowski and R.A. Lindsay Edited by D.A. Ratcliffe and P.H. Oswald This document is part of the above publication. To view or download the complete publication visit: http://www.jncc.gov.uk/page-4322H Appendix Methods of ornithological surveys Methods of data collection used in following was recorded (Reed, these surveys have been described in Langslow & Symonds 1983a): published reports (see section 3.1) and oanest: · by Reed (1982b). For most moorland o a pair with young; bird species, finding the nest of any o a pair acting as if with young (cf Reed given pair is too difficult for this to be a & Langslow 1985); feasible means of population counting o a bird or birds present in the same over the large areas which have to be area on two or more '-'"''"'"'·'"' surveyed. Observation of adult birds in showing signs of attachment to the their nesting territories thus has to be area. the principal basis of census. A territory Breeding densities are expressed in mapping method was used, whereby a this report as pairs per square site was visited several times (usually kilometre. four) in the course of the breeding The analysis of dunlin sightings season. A pair of observers walked a presents great problems. Dunlins series of transect lines across the site breed semi-colonially, have small 200 m apart; thus no part of the site was territories and do not move long more than 100 m from an observer. distances to mob observers. Like snipe, Once decided, the transect ""'"' 1'tc:n·,.., they often behave Problems wasadheredto,with on of obtaining of subsequent visits using the same breeding numbers on machair habitat transects as on the first visit but have been discussed by Reed & Fuller reversing the direction of walking them (1983), Reed, Williams & Webb (1983), on each occasion. taken Jackson & Percival (1983), Webb, Reed frequently to ensure that & Williams (1983) and Fuller, Green & transect lines were used on Visit. (1983). Whilst dunlins breed Weather can adversely affect the at a lower density on blanket bog than number and behaviour of birds seen. on machair, many of the census Recording was not attempted if there problerns are similar. was wind than Force 5 '-'.L•;:;cuc;:,cactivity, and thus or even less in lovv was found in the period cloud or fog. 3-20 June. In estimating the number of On each visit, observers recorded pairs present, we followed the method the birds seen from the transect lines. used by Reed & Fuller (1983): the Each sighting was mapped, using a '"'""""-''-~ of single birds 50 m or more code (including details of behaviour) other birds seen during the period marked onto 1:10,000 maps in the field. 3-20 June (or as close to that period as Any double recording (i.e. when both possible) was taken to a observers saw and recorded the same minimum number method bird during a transect) was corrected at of analysis differed from that employed the end of each line walked. At the end for other species in being based on day a single composite map was data only from the period of peak produced. Not all bird species were activity and not on clusters of records recorded in the early years of from the whole season. surveys. More recently, however, all After the season, vegetation species encountered have been at each site was mapped and then recorded. divided into a grid of200 m x 200 m After each site visit the sightings were squares. Details were recorded, using transferred to a summary of the the provisional categories of the site for each At the of the National Vegetation Classification (Birks season it was thus possible to determine & Ratcliffe 1980). As well as the number of territorial pairs of each vegetational composition species on site from the dusters of square, details of the structure and sightings on the summary map. Birds physical features were recorded, such were as breeding or as presence of pools and dubh lochans, attempting to breed if one of the age and height of vegetation and the 119 amount of regrowth after muirburn. The site to site. Iflarge tracts needed to be selectivity of breeding waders for completed within a single day, particular areas within a site could thus ex1tens101n into the early evening activity be related to detailed habitat did not seriously affect results information (Reed & Langslow in press). et al. 1985). This was because the rise in activity and detectability in the Seasonal timing ofvisits evening was substantially less than in In the course of five years' fieldwork, the early morning. much effort was expended to identify biases in data collection and to evolve a Validation ofmethods standard methodology. Emphasis was The methods used for assessing dunlin placed on determination of optimal densities were tested by Jackson & timing for census visits so that results Percival (1983) during the survey of the would be repeatable and would breeding waders of the machair of the accurately represent numbers of Outer Hebrides carried out by the breeding waders (Lan gs low & Reed Wader Study Group and NCC (Reed & 1985; Reed in prep.). Fuller 1983). The methods were It was found that ideally visits should checked against intensive nest be spaced about three weeks apart. searches and studies on colour-marked Sites were usually visited a minimum of birds in several areas and were found four times, with at least three visits to be consistent, although between l May and 7 July. The most underestimating by about a third. important periods were 16 May to 2 Further checks were undertaken in June, 3-20 June and 21 June to 7 July 1985 and 1986 with similar results (Fuller 'T'hese correspond to the main periods 1985: Fuller & Percival 1986). As of territory establishment, incubation explained above, the same procedure and fledging. At least one visit was for estimating the number of territ0rial made during each of the first two pairs was used the Upland Bird periods. Survey. The methods used to estimate Diurnal timing ofvisits densities of other territorial waders In order to eliminate any biases due to were tested in 1982 in an area of Wales differing detectability of waders at RSPB workers had varying times of the day, diurnal independently searched for nests in an variation in behaviour was investigated intensive survey of breeding waders. by Reed et al. (1983), Reed et al. (1985) This enabled the method to be and Reed & Langslow (in press). in terms both of overall numbers found Dunlins, curlews, lapwings, snipe and by both methods and of the probability golden plovers all showed significant of nest location with respect to distance diurnal differences in detectability. from the transect. Of seven golden Detectability was found to be highest plover nests found by RSPB surveyors, in the early part dawn all were located by NCC tra11sects, (before 09 .00 hours), dropping to a low except that furthest (80 m) from the point in the early afternoon before transect. As a proportion of nests found rising to a second but lower peak of this was 86%. detectability in the early evening. This In 1982 the transect method was had important implications for the scale tested at Kerloch, in Region, and timing of surveys. on an area of moorland intensively Where wide-scale censusing was to searched by the Institute of Terrestrial take place, an early start would have Ecology. The ITE personnel used resulted in a biased estimate for areas trained dogs to locate all golden plovers covered in the first few hours after dawn in a moorland plot of about 500 ha. This when compared with results obtained was then surveyed by NCC workers, during the rest of the day (Reed et al. using the standard transect method. Of 1985). Avoidance of early morning starts the 13 pairs of golden plovers known to provided compatible information from be present by ITE, the NCC observers 120 found 10 (77%) within the study plot. However, one of the pairs was known to have into a nearby field, where it was independently located by the NCC observers, who thus located 11 of the 13 territorial pairs (85%). In no area did the territory mapping locate all nests. Estimates of breeding populations obtained this way must therefore be regarded as minima, particularly for dunlin. Between~year comparisons of breeding wader populations In order to investigate more closely between-year variations in wader breeding numbers and to see what implications these have for site assessments based on a single year's survey, Langslow & Reed (1985} surveyed a number of sites in Caithness and Sutherland in consecutive years. they found that DervvE~er1-vE~ar variation in the densities of moorland breeding waders was relatively low and showed no overall trend for all ""!-''-"'''-·"'·The of on census plots in relation to the mosaic of habitat types did not vary significantly between years. This suggests that, although most Upland Bird Survey plots were surveyed in only one the results accurately represent quality of the areas as habitat for breeding waders. 121