Development of a combined marine and terrestrial biodiversity indicator: research

3. Government objectives for biodiversity conservation, and official indicators used to measure progress against these, in the UK and its constituent countries

9. The UK as a whole has overarching international responsibilities for biodiversity, but biodiversity policy is a devolved responsibility of its constituent countries. England, Scotland, Wales and Northern Ireland have all developed or are in the process of developing their own environmental strategies, policies and underpinning legislation. Ways of measuring progress against these policies, such as biodiversity indicators, are therefore required by each of the devolved governments as well as at the UK level.

10. Here we review biodiversity reporting at the UK and Scottish level, as these are directly relevant to our work on a new Scottish biodiversity indicator. We also present current practice in the UK's other three countries as this may be of use in guiding thinking on developing an indicator for Scotland.

11. The combined biodiversity indicator proposed by this report will be an important measure of progress towards national commitments towards biodiversity. These include the commitments in the Scottish Biodiversity Strategy, and to the national outcome to 'value, enjoy, protect and enhance our environment'. Further than this, it can be regarded as a measure of progress towards targets in the European Union Biodiversity Strategy (such as target 1, to protect species and habitats), and to the global Aichi targets used to assess progress towards commitments under the Convention on Biological Diversity.

3.1 United Kingdom

12. The UK is a signatory to international biodiversity commitments such as the Convention on Biological Diversity (CBD), the UN's Sustainable Development Goals, the New York Declaration on Forests, the OSPAR convention, and the EU's Biodiversity Strategy and Marine Strategy Framework Directive. All these contain policies and targets which require measures of biodiversity change over time.

13. The Joint Nature Conservation Committee (JNCC) currently publishes 24 official UK biodiversity indicators, which contain 49 individual measures, and another five are 'in development'. Last reviewed in 2011 and 2012, they are published annually and were mainly developed for reporting progress against international responsibilities and commitments, e.g. the CBD's Aichi targets (Defra 2018a). Within this suite of indicators there is no overarching single indicator of biodiversity change; however, 27 include a measure of change (defined using either abundance, occupancy, extent, status or quality) in various aspects of biodiversity, including habitat types. These can be divided into three main areas:

• Those that document trends in the abundance and/or occupancy (a measure of geographic range size) of species of different wildlife groups (e.g. priority species, bats, butterflies, pollinators, invasive species, fish stocks, habitat or taxonomic groups of bird species).
• Those that measure changes in site, habitat or ecosystem extent and condition, such as protected areas on land and sea, SSSI's, priority habitats, agricultural and forest area under environmental management schemes.
• A single experimental indicator which attempts to measure habitat connectivity based on the size and distribution of patches of habitat and the relative ease with which typical species, in this case UK butterflies, can move through the landscape.

14. Similarly, in the marine context, a suite of indicators has been developed to assess progress towards Good Environmental Status (GES) under the EU Marine Strategy Framework Directive (2008/56/EC) (MSFD). These also can be grouped by those which document trends in distribution and/or abundance of key species or functional groups (especially fish, marine mammals, and seabirds), and those which quantify changes in habitat extent or condition (particularly of benthic habitats), although there are additional indicators of ecosystem structure and community composition, particularly for pelagic habitats (e.g. plankton community composition) and fish (e.g. size-based indicators of community condition, such as the Large Fish Indicator), as well as multiple indicators of diverse human pressures (e.g. non-native species, contaminants, eutrophication, marine litter) (Defra 2014).

15. As there is no headline indicator for biodiversity change it is hard to obtain a clear overall impression of the state of biodiversity in the UK, and progress towards national/international ambitions. Whilst changes in each of the 49 measures are categorised (improving; little or no change; deteriorating; insufficient or no comparable data) over the long-term (from when data are first available) and short-term (the most recent five years for which data are available), there is no obvious approach that could be used to provide an synoptic overview of these assessments as a whole, particularly as the number of measures for each of the indicators varies widely, and thus a simple summary across the 49 measures would provide a biased impression. Likewise, although there are 11 high-level descriptors of GES under the MSFD, each with clear reporting requirements, there is no single synoptic measure of the status of marine biodiversity available from these.

16. Many of the biodiversity indicators used to measure progress at the UK level, are or have the potential to be used by devolved governments by adopting geographical restrictions to the data.

17. The State of Nature 2019 report (Hayhow et al. 2019) was published in October 2019, giving a high-level overview of trends in the UK's biodiversity, the pressures acting upon biodiversity, and the conservation responses being made to address these pressures. This was the third such report produced by an extensive partnership of conservation, monitoring and research organisations (following Burns et al. 2013, and Hayhow et al. 2016). Notably this partnership expanded in 2019 to include the UK and country Statutory Nature Conservation Agencies, so the report might now be considered as a government-endorsed assessment of the UK's biodiversity. In addition to the UK report, which included short summary accounts for nature in each of the UK's four countries, a separate The State of Nature Scotland 2019 report was also published (Walton et al. 2019) (see paragraph 28 below).

18. The State of Nature reports use a series of high-level metrics derived from species trend data, which have developed iteratively since 2013. As far as possible, the metrics reported at the UK-scale are repeated at the country scale, but issues of data availability and quality limit the ability to do this. The principal metrics published in the 2019 report were as follows:

• Average change in species abundance since 1970, based on trends in 697 terrestrial and freshwater species. This was accompanied by additional measures reporting the percentage of species in each of five classes of change (strong increase, moderate increase, little change, moderate decrease, strong decrease) since 1970 and over the most recent 10 years.
• Average change in species' distribution since 1970, based on trends in occupancy of 6,654 terrestrial and freshwater species. As above, this was accompanied by a breakdown of species' trends into five categories.
• The percentage of species considered threatened with extinction from Great Britain, based upon formal IUCN threat assessments for 8,431 species.
• A range of measures were published to illustrate change in marine biodiversity, but no single headline metric was created.

19. These metrics were accompanied by numerous others, including disaggregations of the principal abundance, distribution and red list metrics by taxonomic group, and many existing measures such as the UK biodiversity indicators referred to above. As well as measures of the state of biodiversity such as these, the report contained many indicators relevant to the pressures acting upon biodiversity (e.g. pollution, farming intensity, invasive non-native species) and the response to help biodiversity (e.g. investment in conservation, volunteer hours donated).

3.2 Scotland

20. The Scottish Government has made strong, high-level commitments to the protection of the nation's rich natural heritage. These commitments are presented by the Scottish Biodiversity Strategy, as defined by "Scotland's Biodiversity: It's in Your Hands" (Scottish Biodiversity Forum 2004), and more recently, by "2020 Challenge for Scotland's Biodiversity" (Scottish Government 2013). The latter made the commitment to "protect and restore biodiversity on land and in our seas, and to support healthier ecosystems". These policies are driven both by the intrinsic value that Scottish people place in the country's natural heritage, but also a growing awareness of the value of maintaining healthy ecosystems for the wellbeing of society. This latter consideration, of the ecosystem services that biodiversity provides, is also recognised in the Scottish Government Economic Strategy. This recognition provides a strong impetus for Scottish Government to consider the needs of biodiversity, and to encourage the embedding of similar thinking within local government, agencies and other public bodies, as well as within business, civil society and individuals. However, the challenges and barriers to the protection and restoration of biodiversity remain considerable.

21. The Scottish Government's National Performance Framework aims to create a more successful country through giving opportunities to all people, increasing wellbeing, creating sustainable and inclusive growth, reducing inequalities and giving equal importance to economic, environmental and social progress. To help achieve its aims this framework has identified 11 core 'national outcome' areas: children and young people, communities, culture, economy, education, environment, fair work & business, health, human rights, international and poverty. In order to measure progress against each of these, the Scottish Government has adopted 81 state indicators.

22. The 'biodiversity' indicator has been identified for revision, and this project aims to identify the most appropriate high-level indicator to measure and report trends in both terrestrial and marine biodiversity in Scotland. Any new metric will need to fit in with the current suite of indicators used to assess progress in other outcome areas. Of the 62 state indicators that currently exist (19 are still in development):

• All are presented as a single index plotted on a line graph.
• 94% are updated annually: four (6%) are updated biennially.
• 71% either represent 'percentage' or 'proportion' change in a defined variable.
• As of the 21^st March 2019, most indicators used data up to and including 2017 (73%), followed by 2016 (16%), 2018 (6%) and 2015 (5%).
• 85% have starting points (first data point) which are since 2005 (52% post 2010). Only four pre-date 2000, with the oldest being the previous biodiversity indicator (the index of abundance of terrestrial breeding birds) which starts in 1994.

23. Apart from 'biodiversity', there are currently seven other indicators identified against the 'environment' national outcome to 'we value, enjoy, protect and enhance our environment':

• Visits to the outdoors: Proportion of adults making one or more visits to the outdoors per week.
• State of historic sites: Percentage of pre-1919 dwellings (sites) classified as having disrepair to critical elements.
• Condition of protected nature sites: Percentage of natural features on protected nature sites found to be in favourable condition.
• Energy from renewable sources: Percentage of energy consumption which is renewable energy.
• Waste generated: Household waste (million tonnes).
• Sustainability of fish stocks: Percentage of fish stocks fished sustainably.
• Clean Seas: Percentage of biogeographic regions with acceptably low levels of contaminants.

24. It is also worth noting the Natural Capital Asset Index (NCAI), which is an indicator identified against the 'economy' national outcome but also has relevance with regards to biodiversity. This is reported as a high-level overall indicator, and as separate lines for three constituent classes of ecosystem services (provisioning; regulation & maintenance; cultural). Levels of ecosystem service provision in these categories are assessed through the quality of habitats providing the services, with the quality of habitats assessed by using a suite of 38 indicators. These cover a wide range of measures, some directly related to habitat quality, others only indirectly e.g. pressures that act upon habitat quality. Measures of biodiversity, such as the woodland bird indicator, are included in this suite.

25. A suite of indicators has been developed by the Scottish Government in order to measure progress against the aims of the Scottish Biodiversity Strategy. These were updated in 2013/14 following the publication of the 2020 Challenge for Scotland's Biodiversity, and fall within two groups; those that measure changes in biodiversity (species, habitats and ecosystems) and those that monitor public' engagement with the natural environment. The former comprises 17 separate indicators (SNH 2019). For each, the last year of data used to create the metric is shown in parenthesis. Some are no longer updated.

• S01 Status of UK Biodiversity Action Plan (UK BAP) priority species – archived (2008)
• S02 Status of UK Biodiversity Action Plan (UK BAP) priority habitats – archived (2008)
• S03 Abundance of terrestrial breeding birds (2018)
• S04 Abundance of wintering waterbirds (2015/16)
• S05 The numbers and breeding success of seabirds (2016)
• S06 Vascular plant diversity (2007)
• S07 Woodland diversity – archived (1999)
• S08 Terrestrial insect abundance: Butterflies (2018)
• S09 Terrestrial insect abundance: Moths (2004)
• S10 Condition of notified species (2016)
• S11 Condition of notified habitats (2016)
• S12 Status of otters in freshwater habitats (2004)
• S13 Freshwater macroinvertebrate diversity – archived (2009)
• S14 Marine plankton – archived (2010)
• S15 Estuarine fish – archived (2005)
• S16 Proportion of commercially exploited fish stocks which are at full reproductive capacity – archived (2007)
• S17 Non-native species: Terrestrial freshwater and marine environments – archived (2001).

26. The Scottish Government has made international commitments to safeguarding biodiversity and publishes annual reports on progress to the Convention of Biological Diversity (CBD) (e.g. SNH 2017); it was the first government in the world to do so. A combined terrestrial and marine biodiversity indicator would allow progress towards the 'Aichi' targets of the CBD and the UN's Sustainable Development Goals (SDG) to be measured. Specifically, a robust biodiversity measure could help assess progress towards Aichi targets 7 (on the sustainable management of areas under agriculture, aquaculture and forestry) and 12 (on the conservation status of threatened species), and disaggregated metrics may also be relevant to targets 6 (sustainable fisheries) and 8 (levels of pollution). It would also be relevant to measuring the success in meeting the Sustainable Development Goals 15 (life below water) and 16 (life on land).

27. Whilst at present we do not know what targets the CBD will adopt post-2020 (dependent on decisions made at the 15th meeting of the Conference of Parties in October 2020), it seems highly likely that they will require high level measures of trends in biodiversity, as measured using species data, and that a new Scottish biodiversity indicator will be relevant for this purpose.

28. The State of Nature 2019 report (Hayhow et al. 2019) was accompanied by a separate State of Nature Scotland 2019 report (Walton et al. 2019), as well as containing Scottish-specific indicators within the UK-scale report. The Scottish report attempted to replicate the UK-level headline metrics as described above, but with adjustments to accommodate restrictions in data availability. The headline indicators were:

• Average change in species abundance since 1994, based on trends in 352 terrestrial and freshwater species. This was accompanied by additional measures reporting the percentage of species in each of five classes of change (strong increase, moderate increase, little change, moderate decrease, strong decrease) since 1970 and over the most recent 10 years. Note the start date for this indicator (1994) is later than that reported for the UK (1970), due to the lack of robust bird trend data prior to 1994. The indicator was based on trends in moths (175 species), birds (143), butterflies (25) and mammals (9).
• Average change in species' distribution since 1970, based on trends in occupancy of 2,970 terrestrial and freshwater species. As above, this was accompanied by a breakdown of species' trends into five categories. It was based on a broad suite of taxonomic groups including vascular plants, bryophytes and many invertebrate groups.
• The percentage of species that occur in Scotland that are considered threatened with extinction from Great Britain, based upon formal IUCN threat assessments for 6,413 species. Note that these are not Scotland-specific assessments, as most taxonomic groups assessed have only been done so at the British-scale. Therefore, for some species the assessed risk of extinction may be due largely to factors outside of Scotland.
• A range of measures were included in the report to illustrate change in marine biodiversity, but no single headline metric was created. Measures of change in demersal fish abundance (separated into the Greater North Sea and Celtic Seas) and an index of breeding seabird numbers in Scotland were shown.

3.3 England

29. The Department for Environment, Food & Rural Affairs published their 25-year Environment Plan for England in 2018 (Defra, 2018b). This sets out the Government's ambitions 'to help the natural world regain and retain good health' in England, through delivering 'cleaner air and water in our cities and rural landscapes, protect threatened species and provide richer wildlife habitats'. One of the goals of the plan is 'thriving plants and wildlife', achieved through a growing and resilient network of land, water and sea that are richer in plants and wildlife. Defra have recently consulted on proposed metrics to measure progress against the Environment Plan goals (Defra 2018c). An indicator framework was published in Spring 2019, including many relevant to biodiversity:

• B7: Health of freshwaters assessed through fish stocks
• C2: Percent of seabed subject to high pressure from human activity, based around measures of intensity of human activity.
• C3: Diverse seas: Mammals, birds, fish, based around abundance and occupancy.
• C4: Diverse seas: condition of seafloor habitats.
• C5: Diverse seas: condition of pelagic habitats.
• C6: Diverse seas: threatened and declining features conserved, derived from the status of the individual features.
• C9: Healthy seas: sea-floor habitats functioning, derived from combining indicators of individual habitats and selected vulnerable habitats.
• D1: Quality, quantity and connectivity of (terrestrial) habitats
• D2: Condition of protected sites - land, water and sea, based around criteria on extent and condition
• D3: Area of woodland
• D4: Abundance and/or distribution of widespread species (birds, butterflies, bats, plants) of farms, woods, wetlands and coasts.
• H18: Healthy Seas: fish & shellfish populations and marine food web functioning. Indicator still in development, type unclear.
• D5: Status of our native species, based around changes in IUCN regional Red List assessments.
• D6: Abundance and distribution of priority species, as specified based around abundance and occupancy.
• D7: Species supporting ecosystem functions. Indicator still in development, type unclear.

30. Unlike for Scotland, there was not a separate State of Nature report published for England in 2019, but a section within the UK report (Hayhow et al. 2019) gave England-specific versions of the UK headline metrics. These were:

• Average change in species abundance since 1970, based on trends in 241 terrestrial and freshwater species. This was accompanied by additional measures reporting the percentage of species in each of five classes of change (strong increase, moderate increase, little change, moderate decrease, strong decrease) since 1970 and over the most recent 10 years.
• Average change in species' distribution since 1970, based on trends in occupancy of 5,942 terrestrial and freshwater species. As above, this was accompanied by a breakdown of species' trends into five categories. It was based on a broad suite of taxonomic groups including vascular plants, bryophytes and many invertebrate groups.
• The percentage of species that occur in England that are considered threatened with extinction from Great Britain, based upon formal IUCN threat assessments for 7,615 species.

3.4 Wales

31. The environmental commitments made by the Welsh Government are outlined within the Environment (Wales) Act 2016, the State of Natural Resources Report (NRW 2016), the Wellbeing of Future Generations (Wales) Act 2015 and the Nature Recovery Plan for Wales (Welsh Government 2015). The latter sets out how Wales intended to address Convention on Biological Diversity commitments for 2020 and beyond, by tackling the underlying causes of biodiversity loss through putting nature at the heart of decision-making, increasing the resilience of the natural environment and taking action for habitats and species. It aims to 'reverse the decline in biodiversity, for its intrinsic value, and to ensure lasting benefits to society'.

32. Under section (10)(1) of the Well-being of Future Generations (Wales) Act 2015, the Welsh Ministers must publish national indicators (46 in total) to measure progress towards their Well-being goals. These Welsh national indicators must be 'expressed as a value or characteristic that can be measured quantitatively or qualitatively against a particular outcome'. Two relate to the health and status of biodiversity:

• National Indicator 43 assesses the Area of healthy ecosystems in Wales. This is an extent/area-based measure and is defined as the extent of semi-natural habitat in Wales (NRW 2018).
• National Indicator 44 aims to assess the 'status of biological diversity in Wales'. It is currently unknown what this indicator will represent as work has been commissioned by the Welsh government, through the Environmental and Rural Affairs Monitoring and Modelling Programme, to explore the potential of the available biodiversity data, primarily terrestrial, to develop an appropriate national indicator. This remains in development (NRW 2016).

33. Unlike for Scotland, there was not a separate State of Nature report published for Wales in 2019, but a section within the UK report (Hayhow et al. 2019) gave Wales-specific versions of the UK headline metrics. These were:

• Average change in species abundance since 1970, presented separately for breeding birds, wintering waterbirds, butterflies and mammals. As the availability of species trends was strongly biased towards birds, it was felt a single metric across the 160 species for which trends were available would be misleading, so a headline metric was not created.
• Average change in species' distribution since 1970, based on trends in occupancy of 2,977 terrestrial and freshwater species. As with other State of Nature headline indicators, this was accompanied by a breakdown of species' trends into five categories. It was based on a broad suite of taxonomic groups including vascular plants, bryophytes and many invertebrate groups.
• The percentage of species that occur in Wales that are considered threatened with extinction from Great Britain, based upon formal IUCN threat assessments for 6,500 species.

3.5 Northern Ireland

34. Valuing Nature: A Biodiversity Strategy for Northern Ireland to 2020 outlines Northern Ireland's ambitions to halt biodiversity loss, through identifying a number of high-level challenges which will require particular attention (DOENI 2015). The Department of Agriculture, Environment and Rural Affairs publish a range of official statistics covering agriculture, environment, rural communities, food, animal health, fisheries and forestry in Northern Ireland. Six of these relate to biodiversity (DOENI 2018):

• Area of nature conservation designations, based around extent
• Condition of features within Areas of Special Scientific Interest (ASSIs), percentage based on a six-year rolling programme of condition assessments
• Land under favourable management, percentage based around "favourable conservation status"
• Marine under favourable management, percentage but definition of favourable is currently unclear.
• Wild birds – abundance-based measure
• Wetland birds - abundance-based measure

35. Unlike for Scotland, there was not a separate State of Nature report published for Northern Ireland in 2019. A section within the UK report (Hayhow et al. 2019) gave Northern Ireland-specific measures, although the constraints of data availability in Northern Ireland (largely due to the smaller size of the country) presented difficulties. The measures presented were:

• Average change in species abundance since 1988, presented separately for breeding birds, wintering waterbirds, butterflies and mammals. As in Wales, the availability of species trends was strongly biased towards birds, hence it was felt a single metric across the 91 species for which trends were available would be misleading and a headline metric was not created.
• There was insufficient data to produce an indicator of average change in species' distribution as published for the UK's other countries.
• The percentage of species that occur in Northern Ireland that are considered threatened with extinction from the whole of Ireland, based upon formal IUCN threat assessments for 2,450 species.

3.6 Outside the UK

36. Whilst we do not intend to provide a comprehensive review of how biodiversity indicators are used to meet reporting requirements at multiple scales outwith the UK, here we reflect on approaches used at the spatial scales (regional, global) in which Scotland and the UK are nested. The EU's Biodiversity Strategy sets out targets to halt the loss of biodiversity and ecosystem services in the EU and help stop global biodiversity loss by 2020 (European Commission 2012). A range of Streamlined European Biodiversity Indicators (SEBI) have been developed to measure certain keys aspects of the natural world relevant to the Biodiversity Strategy targets (European Union 2019):

• SEBI 01 Abundance and distribution of selected species: Common farmland birds and grassland butterflies.
• SEBI 03 Conservation status of species of European interest by documenting changes in favourable or improving conservation status.
• SEBI 04 Ecosystem coverage. coverage of ecosystem classes under the EU 'Mapping and Assessment of Ecosystems and their Services' (MAES) framework
• SEBI 05 Conservation status of habitats of European interest, by documenting changes in favourable or improving conservation status.
• SEBI 07 Nationally designated protected areas- changes in total area
• SEBI 13 Fragmentation of natural and semi-natural areas- changes in artificial and agricultural surfaces and forest connectivity.

37. The Convention on Biological Diversity mandates governments to report on the state of biodiversity on a national scale, and the JNCC indicators previously described have primarily been developed in the UK for this purpose. Other countries have developed similar suites of indicators although the approaches employed vary.

38. The Biodiversity Indicators Partnership is a global initiative to promote and coordinate the development and delivery of biodiversity indicators for use by biodiversity-related conventions, including CBD (Biodiversity Indicators Partnership). For Aichi targets 5 (Habitat loss, degradation and fragmentation), 6 (sustainable fisheries), 7 (on the sustainable management of areas under agriculture, aquaculture and forestry) and 12 (on the conservation status of threatened species) they promote many of the same primary indicators previously mentioned in relation to the UK and its constituent countries, e.g. those based on species status assessments, abundance and distributional indices, extent and condition of habitats and protected sites. However, it does highlight other approaches such as Biodiversity Habitat Index, Biodiversity Intactness Index, Wildlife Picture Index, Marine Trophic Index, proportion of fish stocks within biologically sustainable levels, MSC certified catch, and area of forest under sustainable management: total forestry managed under certification by Forestry Stewardship Council and Programme for the Endorsement of Forest Certification. Many of these are discussed in more detail below.

39. A variety of indicators are used by individual countries to report on progress towards Aichi targets. Table 1 indicates the range of indicators used by a selection of six countries to report on Aichi targets 5, 6, 7 and 12.

40. As well as the indicator types similar to those used for reporting within the UK's four countries (as described above), there are a few different approaches. In the Netherlands, a Living Planet type index has been developed (although not adopted by government), which describes changes in the status of 361 animal species from 1990-2014 (van Strien et al. 2016). This indicator is a composite metric spanning trends in both abundance and species' occupancy - see below for further discussion on such approaches (e.g. paragraph 94). In Norway a 'Nature Index' is used (e.g. Certain et al. 2011, Aslaksen et al. 2015), which incorporates assessments of biodiversity status derived from both quantitative measurement and from expert assessments in order to create a series of indicators for different ecosystems. Each indicator measures distance from a reference state (whereby a value of 1 indicates an undisturbed or perfectly sustainably managed state, and a value of 0 indicates complete degradation), and these indicators are then combined to produce the overall Nature Index.

Table 1: Biodiversity indicators used to measure progress against Aichi target 5 (Habitat loss, degradation and fragmentation), 6 (sustainable fisheries), 7 (on the sustainable management of areas under agriculture, aquaculture and forestry) and 12 (on the conservation status of threatened species) for six example countries ( National Reports)

Indicator type	Netherlands	Canada	South Africa	Norway	Sweden	China
Species abundance index	5, 6, 7, 12	12
Species status assessments	12	6, 12	6	5, 6, 12	5, 12
Red List index			6, 12			6, 12
Defined habitat status and condition		5, 7		5, 6, 12	5, 12	5, 7
Nature index				7
Living planet index						12
Protected area extent or status		6, 7	5		5, 7
Defragmentation of nature	5
Sustainable forestry	7	5, 7			5, 7
Forest regeneration		5, 7
Timber stocks		5, 7				5
Net primary productivity of forest ecosystems						5
Proportion of organic farming area	7					7
Total fresh grass output from natural grasslands						7
Livestock overload rate of natural grasslands						7
Wildlife habitat capacity on farmland		5, 7
Area of agri-environment schemes	7
Environmental farm planning on agricultural land		5, 7
Sustainable fisheries		7
Barriers to fish migration	5
Marine trophic index						6
Marine biodiversity index						6
Area covered by fishery no-take zones						6
Water management				7
The number of plant species with ex situ collections active in restoration programmes			5
Environmental bottlenecks	12
Expert opinion			6, 7		5, 6, 7, 12

41. At a global level, the Living Planet Index (LPI) has been adopted by CBD as an indicator to measure progress against the 2020 target to 'take effective and urgent action to halt the loss of biodiversity' (Living Planet Index). This is a collation of population (e.g. abundance) time series covering over 22,000 populations of 4000 terrestrial, freshwater and marine species. This is however, restricted to vertebrates and excludes all other taxonomic classes (Collen et al. 2009, WWF 2018).

3.7 Summary

42. This chapter reviews the use of biodiversity indicators for governmental assessments of progress towards biodiversity objectives in Scotland, elsewhere in the UK, and internationally. Most nations either publish or are developing biological indicators that assess the condition of specific aspects of the natural environment. The approaches adopted are diverse, but most fall into one of three definitions: the average trend in a measure of species' status (e.g. abundance); species status assessments often based around the IUCN Red List process; extent and condition of protected sites, habitat and ecosystems. The use of indicators showing the average trend in a measure of species' status is widespread, understood and accepted within the UK including within the indicators intended to measure progress against the Scottish Biodiversity Strategy. These existing indicators cover a range of measures encompassing some of Scotland's most valued biodiversity, and collectively give a valuable overview of trends in nature.

43. The State of Nature reports at a UK (Hayhow et al. 2019) and Scotland scale (Walton et al. 2019) published government-endorsed high-level metrics of the status of biodiversity that are reasonably robust and credible measures of change. However, these reports did not publish a single headline indicator.

44. This approach is consistent with that used by the UK and national governments in the UK, which is based on suites of complementary indicators rather than a single synoptic headline indicator, with a range of indicators being used to reflect various aspects of change, and progress towards various goals dictated by national or international policies. To our knowledge, no other country uses a single high-level metric to report on the status of biodiversity as is proposed for Scotland.