2. The Evidence
2.1 An international biodiversity crisis
Globally biodiversity is declining faster than at any other time in human history. The UN's Global Biodiversity Outlook (September 2020) and the IPBES Global Assessment of Biodiversity (May 2019) describe the pressures on nature. Globally there has been:
- An 83% population decline across freshwater species
- A 60% population decline across vertebrate species
- A 41% decline of known insect species
- Over 85 per cent of wetlands (area) has been lost
- 50% of the world's coral reef system has been destroyed
- 32% of the world's forest area has been destroyed
The IPBES report identified five direct drivers of global biodiversity loss:
- Changing use of the land and sea especially for agriculture, forestry, fish farming and coastal infrastructure
- Direct exploitation of organisms via harvesting, logging, hunting and fishing
- Climate change
- Invasive non-native species (and growing prevalence of pathogens)
These direct drivers are associated with a range of indirect drivers of biodiversity loss, including socio-cultural values and behaviours, demographic and consumption factors, poor governance and the impacts of some technological innovations. The global use of natural resources has more than tripled since 1970 and continues to grow. This, in turn, has led to a huge increase in waste of raw and manufactured food and other goods, and an entire industry based on recycling the materials and embodied energy they represent.
Both increased consumption and, in response, production is an outcome of people's increasing distance from, and understanding of how the products they consume are produced and their impact on biodiversity and the natural environment more generally.
In the past 50 years, the human population has doubled, the global economy has grown nearly fourfold and global trade tenfold, together driving up the demand for energy and materials."
IPBES (2019) Global assessment report on biodiversity.
2.2 Scotland's biodiversity crisis
In Scotland, the evidence around the scale and nature of the biodiversity crisis is also strong and continues to mount. Sources include Scotland's Biodiversity Strategy Indicators; Scotland's Natural Capital Asset Index; the 2019 State of Nature report; the Biodiversity Intactness Indicator; Scotland's Marine Assessment 2020; the 6-yearly assessment of progress towards Good Environmental Status under the UK Marine Strategy (updated in 2019); and periodic assessments undertaken by The Convention for the Protection of the Marine Environment of the North-East Atlantic (the 'OSPAR Convention'). This evidence base points consistently to a natural environment that has been heavily degraded, with continued declines across much of our land and seascapes.
In our terrestrial landscapes:
- The Biodiversity Intactness Indicator indicates that Scotland has retained just over half of its historic land-based biodiversity. That is slightly more than other parts of the UK, but Scotland still ranks in the bottom 25% of nations
- Measurements of natural capital indicate it has declined by over 15% since 1950. The Natural Capital Asset Index finds that only around 64% of Scotland's protected woodlands are in a favourable or recovering condition despite being the habitat with the greatest ecosystem services potential in Scotland
- There has been a 24% decline in average abundance of 352 terrestrial and freshwater species since 1994 (noting that 1994 was not a high point) and a 14% decline in range for 2,970 terrestrial and freshwater species since 1970
- An expert review of diversity within species found that of 26 key species selected for assessment, four were classed as being at risk of severe genetic problems. Drought-sensitive plants (mosses and liverworts) have shown strong declines since 1990. Despite recent improvements in air quality, pollution-sensitive lichens have continued to decline since 1971
In our marine environments:
- There was a 38% decline in the Scottish breeding seabird indicator between 1986 and 2016. Abundance indicators for fish species show some signs of recovery from deep historic lows
- Out of 15 components in the UK Marine Strategy, 11 of them had not achieved Good Environmental Status by 2020, with recognition that more action is required. Scotland's Marine Assessment 2020 highlighted declines in biogenic habitats and species such as Atlantic salmon
Across our land and seascapes:
- Scotland's new terrestrial and marine species indicator gives a robust image of the overall picture of decline
- Indicators show an increasing spread of 190 established invasive non-native species (INNS) across Great Britain's terrestrial, freshwater and marine environments during the last six decades – with a northwards shift a common pattern
- SEPA currently classifies only 66% of Scotland's water environment (rivers, lochs, estuaries, groundwater and coastal waters) in good overall condition
- Almost 18% of Scotland's land surface is protected specifically for nature either as SSSIs, SAC, SPA or Ramsar sites and 37% of our seas now form part of the Scottish MPA network. However, only 65% of natural features on protected sites are classed as being in favourable condition, with a further 13% classed as unfavourable but recovering
Efforts to address the biodiversity crisis will be made more difficult by peoples' lack of knowledge of nature and of the benefits it provides. A 2017 RSPB Birdwatch survey, assessing nature knowledge in parents, found that of 2,000 adults, half couldn't identify a house sparrow, a quarter didn't know a blue tit or a starling, and a fifth thought a red kite wasn't a bird – but nine out of 10 said they wanted children to learn about common British wildlife.
2.3 Drivers of biodiversity loss across our land and seascapes
Around 70% of Scotland is solely or partially managed for agriculture (roughly 10% arable and 20% pasture, with the remainder rough grazing which in the uplands is often secondary to grouse moor and red deer estate management).
There have been profound changes in agricultural practices in Scotland over the last century. Prior to the First World War, horses were the primary source of power on most farms, spilled grain provided food for birds such as sparrows and stock ponds and their margins were valuable habitats for a wide range of plants and animals. Since then, increased mechanisation has led to the loss of drinking ponds for working horses or for cattle on their way to market. In some parts of Scotland, the decline in the number of small farms has led to a decline in diversity in the countryside as fields were enlarged and rationalised.
Changes to ploughing and crop rotations, increased fertiliser use and high livestock numbers have negatively impacted soil and water quality, carbon storage and resulted in increasing greenhouse gas emissions. Large-scale heavy grazing and browsing pressures have reduced the diversity, complexity and resilience of soils and plant life, leading to further reductions in invertebrates, birds and other animals. The past 50 years has witnessed a loss of non-cropped habitat and major loss and fragmentation of all farmland habitats.
The outcome has been substantial long-term decreases in key farmland bird populations: declines of more than 50% for greenfinch, kestrel, and lapwing and 25-50% declines in oystercatcher and rook since 1994. There have also been substantial long-term decreases in pollinators and species-rich grasslands, for example a 39% loss of lowland meadows.
There are however some nascent signs of recovery across Scotland's farmland landscape. Many farmers across Scotland have managed to incorporate improved levels of biodiversity through protecting and restoring features such as ponds, hedges and wildflower margins.
Case Study: Farmland Waders
Waders, although often seen in winter in large numbers in coasts and estuaries, migrate inland in spring to nest in upland farmland and lowland moorland. They favour semi-natural, rough grazing or less intensively managed moorland or arable land. Livestock farms in Scotland's marginal uplands provide important habitat. As ground nesters, they like open ground with a diverse sward, for hiding nests and chicks and wet areas with broken ground for feeding on worms and insects.
Kinclune Organic Farm in Angus is an upland grassland livestock farm. Rowan and Marguerite Osborne bought Kinclune in 2002 and underwent the organic conversion process. After 16 years, they remain committed to organic management with the benefits of lower input costs and organic premiums on their produce as well as seeing increased biodiversity.
Their daughters, Virginia and Aylwin, members of the Nature Friendly Farming Network, are continuing the livestock business, alongside agri-tourism. They have been working with the RSPB and Working for Waders since 2020 to improve wader habitat on Kinclune. Organic grazed grassland provides superb breeding habitat and Kinclune boasts five species of vulnerable protected wader: Curlew; Lapwing;Common Snipe; Oystercatcher and Redshank. The UK population of these once common species is in decline, with Curlew and Lapwing on the UK Red List of species most at risk, while the Common Snipe, Redshank and Oystercatcher are on the Amber List. Scotland holds an estimated 15% of the global breeding population of Eurasian Curlew.
The sisters' approach to wader conservation is five-pronged:
(1) habitat improvement and creation, including removing trees which provide predator perches, creating wader 'scrapes' (shallow pools for feeding) and re-wetting areas of formerly improved, but unproductive, land
(2) sward management, through rush cutting and livestock grazing management, including exclusion or low density grazing where appropriate
(3) nest identification, monitoring and protection through grazing management and altering the farming calendar (including silage cutting)
(4) monitoring and reporting breeding success with the RSPB and Working for Waders and adapting farming practices accordingly, as well as contributing to NatureScot supported research and data collection, and
(5) controlling predators, including foxes and corvids, which predate eggs and chicks.
Although the sisters' approach to wader conservation is comprehensive, they are keen to encourage other farmers, demonstrating that small changes to farm management practices can make a big difference to our severely threatened species.
The drainage of ponds and marshes has increased the rate and extent of wetland loss. Reduced water storage capacity and soil compaction has intensified flood risk. Soil erosion through cultivation and trampling by animals close to watercourses has added individually small, but cumulatively large, pollution loads to freshwater bodies. Nitrogen pollution and nutrient enrichment of water courses and bodies is linked to a reduction in the diversity of aquatic plant and animal life.
Scotland's uplands (above the limits of enclosed farmland) comprise a range of habitats including moorland, rough grassland, blanket bog, woods and species-rich grasslands. The majority of this land is managed for field-sports and livestock grazing and some multi-functional uses (e.g. renewable energy, nature conservation and amenity interests). Management practices giving rise to high stocking densities of sheep, heavy impacts of grazing, browsing and trampling by deer and inappropriate muirburn especially on deep peat has led to the degradation and loss of upland and peatland habitats. Deer management groups across the Highlands have made significant efforts and progress to reduce upland deer populations. However, more work is required to allow our habitats to regenerate. Overall at least 25% of wider uplands are considered to be in poor condition. A range of species and habitats are declining, especially waders, hen harriers, mountain willow and juniper. The greatest decline in birds has been in uplands, with 18% decline since 1994; 17 species contribute to this indicator with nine in long-term decline.
Scotland is the most wooded of the UK countries (19% woodland cover) but this is well below the current European average of 37%. Approximately a third of Scotland's woodland is considered native. This includes globally important areas of Scottish rainforest, including oak and hazel woodland, and Caledonian pine forest – recognised as being of very high value to biodiversity, but currently fragmented, lacking understorey and restricted in range. Woodland biodiversity faces a challenge from red and roe deer numbers and ranges, and invasive non-native species, specifically rhododendron, which restrict natural regeneration, habitat restoration and undermine replanting efforts. However there are positive signs we are turning the tide: Scotland is currently creating around 80% of the UK's new woodland – 40% of which is native and the woodland birds indicator shows a positive trend (increasing 58% between 1994-2018),
Urbanisation continues to steadily impact on lowland particularly through the expansion of low-density housing and associated developments. Some species like amphibians are good at exploiting urban infrastructure such as sustainable drainage systems but others struggle in modern cities with urban birds declining steadily since the early 2000s.
In our rivers, lochs and wetlands
Scotland's rivers, lochs and wetlands supply drinking water, support fisheries and aquatic biodiversity, generate hydropower, mitigate flood risk, store carbon and are an essential resource for business and recreation.
The Scottish Environment Protection Agency's (SEPA) monitoring shows that overall 64% of our rivers and lochs are in good or better than good condition in 2020. This is based upon an assessment of water quality, flows and levels, physical condition and barriers to fish migration. This is an improvement of three percentage points since 2015. Scotland's third River Basin Management Plan (2021-2027) and the Wild Salmon Strategy are key. The former plan aims to achieve 81% of the water environment being in a good or better condition by 2027 and 90% in the long-term once natural conditions have recovered.
Issues which need tackling include increasing water scarcity and abstraction, rising water temperatures, rural diffuse pollution, wastewater, man-made barriers to fish migration and physical modifications to rivers, invasive non-native species (INNS) such as Japanese knotweed, giant hogweed and North American signal crayfish have considerable impacts on freshwater ecosystems and these are intensifying. Healthy riparian woodlands are critical for the health of water systems and bodies but they are in declining in coverage and condition. Poorly vegetated upper catchments and canalised river systems exacerbate downstream flash flooding events.
In marine environments, seas and on our coasts
Scotland's seas are highly dynamic, supporting a diverse range of habitats and species. They are of significant cultural and socio-economic importance, especially to local coastal and island communities, and support an array of marine industries. If managed sustainably, Scotland's seas can continue to provide a range of ecosystem services, including food (through fishing and aquaculture) and renewable energy.
Scotland's Marine Assessment 2020 (SMA 2020) highlights the increasing impacts of climate change and ocean acidification. It notes that disturbance of the seabed by bottom-contact towed fishing gear remains a significant, and the most widespread pressure, with the 'no loss in extent' target for subtidal biogenic habitats indicator not being met. The last 30 years have also seen significant changes in the plankton community with potential implications for marine food webs, including commercial fish species. The abundance of some offshore whales, dolphins and porpoise has remained stable, whilst the abundance and distribution of coastal bottlenose dolphins on the east coast has increased. The grey seal population has increased but while the harbour seal population is recovering on the west coast, it continues to decline in the North Coast and Orkney Islands marine regions.
Seabird numbers have been largely stable since 2011, but at a greatly reduced level compared to the 1986 baseline. Across species there are markedly different trends with the most significant decreases in surface-feeding birds. Overall, Scotland's wintering waterbirds continue to increase in abundance, although species exhibit different trends with some changing their range in response to environmental change.
Scotland's coastal habitats are experiencing pressure from climate change. Rising sea levels and larger and more frequent storm-surges are causing erosion and reducing the connectivity of some beach, dune and machair habitats. These factors have led to changes in species composition. Saltmarshes and some dune systems play an important role in increasing the resilience of coastlines to these pressures by reducing and absorbing wave energy and providing a buffer for sensitive inland habitats. However, these may be adversely affected by higher seasonal rainfall, increasing variation in groundwater and freshwater run-off.
Scotland's estuaries are vital for waterbirds such as waders, ducks and geese. They provide safe feeding and roosting areas, enabling many thousands of waterbirds to use them as places to winter and refuel on their way to other destinations. Climate change is resulting in shifts in populations of some of our waterbirds, but coastal areas in Scotland remain internationally important.
2.4 Positive Signs: Building on what works
The evidence above paints a picture of a deep biodiversity crisis – in terms of both breadth (across all land and seascapes) and depth (the status of biodiversity compared to historical baselines). Within this overall picture of decline, we are seeing some positive signs of stabilisation and recovery within some habitats and for some species, albeit from a low base. They are fragmented and fragile especially in the light of climate change pressures. And they are not enough in terms of the rate and scale of recovery needed to bend the curve of biodiversity loss and deliver a nature positive Scotland.
These indications of a recovery need to be nurtured and intensified. Building on and accelerating what has worked will be critical. Across Scotland there is a rich body of evidence, expertise and practical experience to build on:
- The establishment of the Millennium Forest was one of the early significant attempts to halt the loss of biodiversity at large scale. Some of the project success is evidenced in a recent report Scotland's biodiversity: a route map to 2020
- The South of Scotland Golden Eagle Project has overseen the release of 25 eagles since 2018. As a result there are now more golden eagles in south Scotland than at any time recorded in the last two hundred years. Effective community engagement has been the cornerstone of success, with more than 10,000 volunteers and project participants of all ages
- Home to over 60,000 pairs of puffins, around 8,000 razorbills and 9,000 guillemots the Shiant Islands were declared rat free in 2018 marking successful completion of the Shiant Isles Recovery Project coordinated by the RSPB, with support from the European Union's LIFE programme (LIFE+), NatureScot and the landowner
- The globally important freshwater pearl mussel population supported through the physical restoration of rivers in priority catchments as part of the Pearls in Peril EU LIFE+ project
- By the end of 2021, volunteers in the Scottish Invasive Species Initiative (SISI) had contributed over 90,000 hours to eradicate Japanese knotweed with herbicide injections across hundreds of sites, thus reducing this invasive species at many locations across multiple catchments
- Landscape-scale restoration projects in our National Parks
- The Green Infrastructure Strategic Intervention has allocated over £15m to projects creating multifunctional green infrastructure in some of Scotland's most deprived urban areas. These projects are delivering multiple benefits for people and nature including improving habitat for biodiversity, helping people to connect with nature and involving local communities in citizen science and habitat management
- The NHS Greenspace Demonstration project worked across 13 sites with 5 health boards to increase the biodiversity value of 87 hectares of the NHS estate, planting 11,000 trees, establishing 4 therapeutic gardens and creating 1.4 hectares of wildflower meadow
- Since 2013/14 Scottish Forestry has supported the establishment of 31,544 ha of new native woodland; an average of 3,504 ha per year. In 2021/22 4,362 hectares of new native woodland was created, representing 42% of all new woodland created that year
- The Alliance for Scotland's Rainforest has developed an ambitious 'Saving Scotland's Rainforests Action Plan' to be implemented beyond 2020
- The partnership programme Peatland ACTION is putting more than 35,000 hectares (ha) of peatland on the road to recovery. Flows to the Future Project (2014 to 2019) is restoring large areas of blanket bog in the heart of the Flow Country that had been damaged by forestry planting
The challenge ahead is to build on the nascent signs of nature recovery and the successes above – and accelerate progress to drive landscape and seascape scale change.
Case Study: Landscape Scale Catchment Restoration in Glen Muick
A river catchment is an area where water is collected naturally by the landscape. Planning nature restoration at this scale allows projects to be located in the best place, taking account of the shape of a glen, structure of a river network and other natural features, such as floodplains and landscapes.
The River Dee Trust and the Dee District Salmon Fishery Board, supported by the Cairngorms National Park Authority, have been working with land managers to re-naturalise one of the major upland tributaries of the River Dee, the Muick. This is a great example of landscape scale river restoration bringing long term, multiple benefits. River restoration, alongside nearby peatland restoration and woodland expansion, will benefit many species and deliver multiple ecosystem services.
- Removing flood banks and creating shallow scrapes has reconnected the river with natural channels and floodplains, which will reduce the impact of floods, droughts and low flows, and improve water quality.
- Large trees and roots anchored to the riverbed naturally create new pools and gravel beds, shelter from predators and a source of invertebrates; spawning and feeding grounds for species including salmon and freshwater pearl mussel.
- Deer legs, leftovers from surrounding sporting activities, tied to the riverbed, pump nutrients into an impoverished system.
- Riparian woodland planting in previously bare uplands supplies the fallen trees of the future and shades burns which are now too warm – lethal to young salmon.
- These works are also catalysing a new, green economy – creating jobs in the design, build and monitoring of restoration schemes as well as supporting the traditions and economy of an internationally renowned salmon fishing river and creating a more sustainable, resilient river of the future.
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