Scotland's Biodiversity: It's in Your Hands
A strategy for the conservation and enhancement of biodiversity in Scotland
In this section we explore the nature and value of biodiversity in Scotland. We also consider the state of our biodiversity, and look briefly at some factors which underpin habitat and species diversity, and the possible effects of climate change.
2.1 The nature of Scotland's biodiversity
Scotland is special. Not so much for the sheer number of species that live here (though we do have around 90,000) but rather for the mosaic of habitats and scenery which make up such a complex and varied landscape.
Scotland is a crossroads - of climatic zones and ocean currents, of arctic and temperate species. Weather systems typically build from the south west, bringing us relatively warm and wet weather, especially in the west; and this is complemented by the tempering influence of the Gulf Stream. But Arctic air frequently pushes back westwards to bring the cold crisp days of winter and cool spring sunshine. Arctic currents push into the North Sea from time to time, reinforcing the distinct climates of east and west.
This climatic variation is complemented by a great range of geology, landforms and nature. The physical landscape throws up a tremendous variety of coastline, islands and undersea formations; glens, mountains and plateaux; rivers, lochs and floodplains. And in each and every one of these environments, from seabed to summit, nature has woven a rich tapestry alive with myriad species of plants and mammals, bacteria and birds, fungi and fish, reptiles, amphibians and invertebrates.
Then, over all of this, mankind has transformed the detail of the landscape and the dominant vegetation down through millennia.
Our national and international assets
In all, Scotland has 65 out of the total 159 conservation priority habitats listed in the European Habitats Directive. And because of the variation in climate and landform, many species in Scotland find themselves at the extreme of their range or living in atypical habitats, where they have adapted as local varieties.
Our country is internationally important for its heather moorland, its upland blanket bog and lowland raised bog, for its machair, and for its freshwater and seawater lochs. Some of our mountain summits are akin to Arctic tundra, while on the west coast there is our 'temperate rainforest'.
Our latitude, coastline and pastures combine to create an internationally important habitat for migratory waders and wildfowl. Our rich seas support 244 species of fish, amazing populations of seabirds, and a range of fascinating mammals: seals, whales and dolphins. And throughout all these habitats live some 25,000 largely unknown invertebrates.
The eagle, deer, salmon, grouse, grey seal, capercaillie, Scots Pine, red squirrel, heather and thistle, to name but a few, are all enduring symbols of Scottish culture and enterprise. Biodiversity lies at the heart of the Scottish identity.
White-tailed eagle. Adult seizing fish from sea.
Courtesy of RSPB
Some 90,000 species ...and still counting
At one end of the scale we have at least 40,000 species of virus, bacteria and protozoa, some 24,800 species of invertebrates, and 20,000 different plants and fungi. At a more comprehensible level, we also have 242 species of birds, 63 different mammals and ten species of reptiles and amphibians.
Young frog on teasel leaf
Courtesy of SNH
The secret life of seaweed
In the clear waters around many of our west coast and islands can be found a rich and unusual habitat - several species of calcareous red seaweed growing on the seabed. European maerl supports over 1,700 animal species and 300 seaweed species. A recent study of Scottish maerl beds found species previously unknown to science.
Maerl Bed, West of Wyre Skerries, Wyre Sound
Courtesy of SNH
A rainforest close to home
On the west coast of Scotland and on some of the larger islands grow ancient oceanic woodlands - so rich in species that these forests has been likened to that of temperate rainforest. Oak, birch, bird cherry, rowan, alder and many other familiar trees grow in these woods. But what is truly remarkable is the variety of mosses, liverworts and lichens which thrive in the moist, stable oceanic climate and the unpolluted air.
A coral reef to call our own
In the deep waters to the west and north off Scotland are corals, growing on the seabed, in some cases in large reef-like colonies. The main species involved, Lophelia pertusa, is as beautiful and remarkable as many of its tropical relatives, and colonies support more than 800 animal species. Even more remarkable, it is thought to grow in water up to 3,000m deep. These reefs were being rapidly destroyed by deep water fishing trawls until fisheries control measures were introduced in 2003 to protect them.
2.2 The value of Scotland's biodiversity
Biodiversity has always been a source of wealth and a stimulus to culture and enterprise in Scotland. Ours is a land renowned worldwide for its clean air, clean water, wilderness areas and seascapes, and for the biodiversity associated with these natural attributes.
Atlantic salmon leaping up a waterfall on the River Almond
Courtesy of SNH
Our nation has been built on its biodiversity. Herring, cod, haddock, and salmon were critical to the development of our economy, our seagoing skills, our infrastructure, and the nutrition of our growing industrial cities.
Forests and forest products formed the basis of shipbuilding, and the economies and trade associated with it. Deer and grouse underpin the economy of huge swathes of the uplands. While, in farming, where much of the genetic biodiversity is influenced by man, we have domesticated breeds or varieties - of both crops and livestock - which are renowned worldwide.
Our dramatic landscapes and seascapes, and the biodiversity they host, also underpin the tourism industry which employs more than 9% of the Scottish workforce and contributes more than 4.5 billion to our national economy. In addition, economic growth in some scenic areas of north and west Scotland is closely linked to the quality of life associated with this environment, and the value that many people place on this.
Likewise, people who live in urban environments are increasingly realising that the green spaces around them are important. They add texture to life; provide opportunities for outdoor activity and healthy living; and provide a platform for learning.
The nation's health and wealth
Biodiversity is important for our health - individually and as a nation. Fully functioning ecosystems provide us with healthy and productive environments which support the economy of rural and coastal areas. Bacterial biodiversity gives us productive soils and clean water. Without our forests, bogs and the plankton in the sea, the greenhouse effect would be even more serious.
There are also many practical applications of biodiversity. People forget that the first antibiotics came from a simple mould - discovered by a Scot. And there are literally thousands of other Scottish plants, fungi, bacteria, plankton and fish which have, or could have, applications in medicine, healthy eating, pest management and a whole host of other important products and areas.
Biodiversity is not just beautiful and fascinating, it is an investment for the future. Our fisheries show what can happen when we don't get the management right.
So what's biodiversity worth?
Many people have tried to put a cash value on biodiversity, but it is an exercise fraught with difficulty. Different analysts provide different estimates, but the figures for existing values are always high, and for potential value, almost infinite. But more importantly, the cost of losing any significant part of our biodiversity cannot be calculated - and may be enormous. A small loss may seem unimportant, but lots of little losses soon add up to a substantial loss; a loss that would deny future generations a wealth of cultural, scientific and commercial opportunities; and in the extreme, a loss may threaten the very stability of our ecosystems, and the quality of our soil, water and air.
The value of wildlife tourism
Wildlife tourism is growing in popularity and now generates substantial income for the economy, especially in more remote parts of Scotland. Whale and dolphin watching generates around 3.4 million per year; visiting osprey sites generates around 1.7 million; and a long established recreation - angling on the Tweed - generates 12.5 million. The total generated by all forms of wildlife-related tourism, and its contribution to mainstream tourism will be far higher.
The value of our plants
Flora Celtica is an international project based at the Royal Botanic Garden, Edinburgh, documenting and promoting the knowledge and sustainable use of native plants in the Celtic countries of Europe. For example, its records tell us how bog myrtle, a distinctive shrubby plant of moorlands, has traditionally been used to flavour and preserve beer, as a garnish for food, and as an insect repellent. Indeed, in 1995, a commercial repellent for midges based on bog myrtle was produced on Skye under the trade name Myrica.
Interpretation Board, Vane Farm RSPB Reserve
Courtesy of RSPB
Greenspace comprises between 10% and 40% of the area of the major Scottish towns and cities. This is a huge resource, potentially rich in biodiversity, which is close to the majority of the people in the country. There are tremendous opportunities to combine increased biodiversity with better access, learning facilities and promote healthy living more generally.
2.3 The state of Scotland's biodiversity
We may not have control over many of the factors affecting our biodiversity - climate, ocean currents, rocks and the basic physical structure - but people have been a major force in shaping our landscape and biodiversity for thousands of years and our influence continues. While some of our activities have benefited biodiversity, many have resulted in declines. Some of these declines are now slowing or being reversed, but much of our biodiversity is still under threat.
Forestry, Craigmore Wood viewed from Dulnain Bridge
Courtesy of RSPB
The main changes in biodiversity experienced in Scotland relate to the felling of ancient forest, the grazing of sheep and deer, the intensification of agriculture and commercial fishing, the planting of non-native conifers, the spread of urban development, the introduction of fish farming, and the increase in pollution.
Measuring the impact of these changes is difficult. Clearly it is an impossible task to monitor the status of all 90,000 plus species, so the data we have is by nature very selective. Nonetheless some major trends can be recognised, and many species serve as indicators of broader change.
Some of our rarest species and habitats are continuing to decline in status, a few are beginning to recover, thanks to conservation action and investment; but half show no sign of significant improvement, despite our efforts so far.
Good news and bad news
The summary below gives a very brief and necessarily selective overview of some key trends. A more comprehensive analysis was made in: Towards a Strategy for Scotland's Biodiversity: Scotland's Biodiversity Resource and Trends. Scottish Biodiversity Forum, Scottish Executive 2003.
Marine and freshwater environments
After a long period of decline, the quality of water in our rivers and lochs has improved, related to the decline of heavy industry along with better effluent regulation and sewage treatment. The loss of the otter in the lowlands has been reversed, suggesting that some fish and crustaceans have also returned. These improvements are encouraging. Nevertheless, further conservation efforts are required for many freshwater species. For example, the freshwater pearl mussel, of which we hold 50% of the world's population, continues to decline. In fact, in 2000, some fifty percent of native freshwater species were thought to have declined throughout Scotland. The extinction of the Scottish population of the vendace - a freshwater fish - in 1980 illustrates what can happen if we fail to take appropriate action in time.
Otter on riverbank
Courtesy ofLorne Gill/SNH
The quality of our coastal waters has generally improved in recent years, again benefiting from better sewage treatment and stricter regulation of industrial effluents, coupled with a decline in industrial activity. Related to this, the Clyde and Forth are again showing a greater diversity of invertebrates and fish. Many seabird populations in Scotland have also increased, but some species such as the cormorant, kittiwake and roseate tern have shown marked declines. This mixture of positive and negative is typical of the trends we are seeing in many of our distinct environments, clearly further action is required where species are still showing decline.
Fishing undoubtedly affects biodiversity. The North Sea has been intensively trawled for decades, and the range of sea bed creatures has been altered. Scavenging crustaceans and starfish have displaced bivalve molluscs and other long-lived species. Out of 21 commercially exploited fish stocks in 2003, 16 are currently considered to be fished beyond safe biological limits. This in turn has led to the exploitation of deep water, slow growing, long lived and therefore more vulnerable species - such as orange roughy, and to damage by trawlers of deep water Lophelia coral reefs.
Farmland and woodland
On the land, there have been some notable improvements in recent years, but the news is not all good. Throughout most of the last century increasing intensification in agriculture, and the spread of urbanisation, have led to the loss of much of our semi-natural land, as well as many of our hedgerows and farm ponds. As a result, farmland birds, wildflowers, mammals and pond-life have all declined.
After a period of decline in forest cover, followed by intensive planting with non-native conifers, we are now seeing an increase in the area of woodland with native species. Over the past 20 years there has been a significant shift to more sustainable forest management, including diversification of planted forests, and restoration of management in degraded native woods.
The overall trends in woodland birds are mixed. Some have increased their range and numbers, others have decreased. One of the most notable species in decline is the capercaillie, now down to a mere 1,000 or so birds.
Mountains, heaths and bogs
Moorland, peatland and rough grassland cover 50% of Scotland's land area, and in many ways define the character of Scotland's landscape. But these habitats have changed significantly since the 1940s, and while the rate of change has slowed in recent years, some of the trends continue.
Badanloch Bogs, Ben Griams, Sutherland
Courtesy of Steve Moore/SNH
The area of heather moorland has declined as a result of afforestation and conversion to grassland. There has been a reduction in regeneration in some areas as a result of large increases in grazing pressure by both sheep and deer. Montane heath has declined, probably as a result of a combination of grazing pressure, nitrogen enrichment and possibly climate change. Afforestation, agricultural practices, and peat extraction have all contributed to declines in blanket bog and lowland bog. Many of our grasslands have lost species richness due to reseeding, fertilisation and more intensive management. Illegal persecution of raptors continues to be a problem in many areas.
There is some good news though. The total area affected by potentially harmful levels of nitrogen deposition is expected to decline significantly in the years to come, and changing incentives under the EU common agricultural policy should eventually lead to more appropriate grazing regimes for sheep. And, as noted above, forestry policy and the incentives associated with it, have changed in favour of biodiversity conservation in recent years.
Guarding against invaders
Human activity - either accidental or deliberate - can introduce non-native invaders which damage our native biodiversity.
Escaped North American mink are one of the reasons why the native water vole is now so rare, as they are serious predators of voles, while a fish called the ruffe, introduced in Loch Lomond by anglers, is decimating some of the very special native fish that live there as they out-compete them for food and have higher survival rates. Sika deer now occupy one third of the red deer range - and interbreed with them, harming the genetic integrity of our native species. The introduction of hedgehogs to the Western Isles has wreaked havoc among internationally-important breeding wader populations as hedgehogs eat their eggs. The giant hogweed is now quite common on disturbed ground, where it smothers native plants, as well as causing injury to children every year. With huge increases in large scale marine traffic, alien marine organisms have been spread to new areas when ballast waters are discharged.
The impact of non-native invaders can be rapid and uncontrollable, so we need to guard against the threats, and manage them carefully when they arise.
Courtesy of SNH
2.4 What are the implications of climate change?
Air and sea temperatures are predicted to increase significantly in the 21st century - by as much as 2 to 3°C. East coast waters will warm at a greater rate than those in the west. We can anticipate wetter autumns and winters, drier, hotter summers and more unpredictable weather events. Changes in precipitation will affect run-off and erosion. These changes will affect biodiversity.
Already there are signs of change. The nuthatch and kingfisher appear to be moving north. In the future, birch may increase in pinewoods, oak may increase around the margins, and the tree-line will probably shift upward from its current level of 650m. Arctic-alpine habitats may disappear completely from our mountain tops, along with birds like the dotterel and snow bunting.
In the marine environment, there is likely to be an increase in the number of southern species entering our waters; but we may lose species such as the sea-pen, the green sea urchin, and possibly the cod. Sea level rises - predicted at up to 70cm by 2080 - will affect coastal habitat, and this rate of change may be greater than the rate at which some species can adapt.
But perhaps the most important issue will be the extent to which species can shift their range as climate change takes place and sea levels rise. If they can adapt, the impacts on biodiversity will be limited and possibly positive. But for many less mobile species - especially on land where their habitat is already fragmented this shift will not be easy. So in addition to working towards targets to reduce greenhouse gases, we need to plan for these shifts, by maximising the connections between habitats and minimising the barriers to movement and dispersal.
Managing coastal realignment
Every year 100 hectares of saltmarsh and mudflats are lost in the UK as a result of rising sea levels and erosion. These are key habitats for biodiversity - many being internationally recognised for their importance for wildlife.
Whilst it may be some years before international action to cut the emission of greenhouse gases yields real results, there is already much being done to adapt to the predicted effects of climate change on our coasts. In February 2003, the seawall at Nigg Bay was breached allowing a 25 hectare field to flood and revert to intertidal habitat using a process known as 'coastal realignment'. This is the first time that this approach to dealing with rising sea levels, flood risk and coastal habitat loss has been tried in Scotland.
Nigg Bay Realignment Site, Nigg Bay, Cromarty Firth
Courtesy of RSPB Scotland
Bogs and so much more
The quality of Scotland's bogs and marshes is recognised worldwide, though most people don't always recognise them as assets. But they are! Bogs have been storing carbon in the form of peat for thousands of years - if they are drained and allowed to dry out this carbon is released into the atmosphere, adding to the greenhouse gases, which are causing climate change.
Bogs and marshes also reduce the risks of flooding, serving as a buffer against rapid run off during exceptional downpours. They help maintain a consistent supply of clean water to rivers and lochs including Scotland's famous game fishing sites. And if this were not enough, bogs and marshes are also home to special plans, birds and insects not found elsewhere. The carnivorous sundew, the bog asphodel, the dunlin, snipe and golden plover; the great variety of small, often unnoticed but nonetheless beautiful sphagnum bog mosses and liverworts.
Sphagnum moss bog pool, Creag Meagaidh National Nature Reserve (NNR)
Courtesy of SNH