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C7. Plants of the wider countryside

a. Arable field margins

b. Bog and wet heath

c. Broadleaved woodland & hedges

d. Lowland grassland

Type: State indicator

Experimental statistic: The UK biodiversity indicators project team would welcome feedback on the novel methods used in the development of this indicator.

Indicator Description

This indicator measures, in small plots, change in the abundance of plant species considered indicative of good habitat condition in the UK, using modelled abundance data from the National Plant Monitoring Scheme. Plant populations form the environment in which most other species exist, as well as providing numerous ecosystem services. Drivers of change are well-understood for many UK habitats.

This indicator is presented for 4 UK broad habitat types: Arable field margins; Broadleaved woodlands and hedges; Bog and wet heath; and Lowland grassland. Within each habitat, plant species abundance trends indicative of good condition, are averaged to provide an indication of the habitat’s current state.

Key results

In 2019, average indicator plant abundance for all 4 habitat types presented remains below the 2015 level (Figure C7i):

  • arable field margins, while fluctuating annually, shows an overall decline of 27% between 2015 and 2019;
  • bog and wet heath after an initial decline of 34% in 2016, shows a steady rise to 83% of the baseline;
  • broadleaved woodland and hedges shows a decline of 18% before levelling off; and
  • lowland grassland shows a decline followed by a gradual rise to 95% of the level in 2015.

As this is an experimental statistic it has not been assessed. The UK biodiversity indicators project team would welcome views on the value of this new indicator (i.e. is this measuring something readers feel should be measured?) and the quality of the new indicator (i.e. how well does it measure plant abundance?).

Figure C7i. Abundance of plant species in 4 UK broad habitat types, 2015 to 2019.

Four line graphs showing changes in the abundance of plant species from 2015 to 2019 in four UK broad habitat types: arable field margins, bog and wet heath, broadleaved woodland, and hedges and lowland grassland. In 2019, average indicator plant abundance for all 4 habitat types presented remains below the 2015 level.

Notes:

  1. The line graphs show the unsmoothed trends (dashed line); the variation around the lines shown (the shaded area) is the standard deviation of 1,000 simulated trend indices calculated according to the method of Soldaat et al. (2017).
  2. Abundance is measured by the percentage area covered by a species within a plot.
  3. The figures in brackets indicate the number of species or species aggregates included in the composite index for that particular habitat type.

Source:  Botanical Society of Britain and Ireland, Joint Nature Conservation Committee, National Plant Monitoring Scheme, Plantlife, UK Centre for Ecology & Hydrology.

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Indicator description

The National Plant Monitoring Scheme (NPMS) was designed to monitor UK habitats of conservation importance. This is achieved through the establishment of small plots in areas of habitats targeted by the scheme. The abundances of plant species, measured as the percentage area covered by a species within a plot, are recorded each year. Surveyors record from different lists of indicator species depending on their level of experience and the habitat within which a plot is located. Both the placement of plots, and the selection of one-kilometre national grid squares within which the plots are located, are subject to statistical methodologies designed to minimise bias (Pescott et al., 2019a).

The design of the NPMS included the definition of a set of 11 broad habitat types, within which 28 finer habitat types are nested. These fine-scale habitats are linked to existing classifications such as the British National Vegetation Classification. Surveyors can choose, based on their knowledge of a habitat, whether to record a plot at the broader or finer level.

The current indicator summarises species’ percentage cover (abundance) data at the broad habitat level. This is done using a model that is able to account for both the range of percentage covers that a species may exhibit in a habitat when present, and the fact that species may often be absent from any given plot (Pescott et al., 2019b). Such data are often described as “zero-inflated”. This model is applied across years for each species/habitat combination, and the indicators presented here for each broad habitat are the result of combining the resulting species/habitat time trends across the relevant set of NPMS habitat indicator species. The 4 broad habitat measures presented in this indicator (Arable field margins; Lowland grassland; Broadleaved woodlands and hedges; and Bog and wet heath) are those for which the largest numbers of NPMS plots currently exist. See the technical background document for more detail.

As this is an experimental statistic it has not been assessed.

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Relevance

Plants are a large part of the fundamental fabric of which habitats are made and directly indicate changes to environmental conditions and habitat management. Plants provide essential habitats and food for wildlife, and essential ecosystem services for humans, such as reduced erosion, nutrient cycling, oxygen production, and climate regulation. Furthermore, many plants, such as bluebells (Hyacinthoides non-scripta), horse chestnut (Aesculus hippocastanum) fruits (conkers), heather (Calluna vulgaris), oaks (Quercus spp.) and brambles (Rubus spp.) have deep cultural significance and are valued in their own right by the public.

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Background

The creation of the NPMS allowed for the creation of annual trends in the abundance of plants in habitats of conservation importance. Following 5 years of development, the scheme was launched by a partnership consisting of the Botanical Society of Britain and Ireland (BSBI), the Joint Nature Conservation Committee (JNCC), Plantlife, and the UK Centre for Ecology & Hydrology (UKCEH) in 2015. This indicator uses species selected by the NPMS as indicative of good condition in those habitat types considered to be of most importance for the conservation of UK biodiversity – see the technical background document for a full list of species included. These species are monitored in small sample plots (between 25 and 100 m2 in area) according to a methodology that was designed to minimise biases in data collection.

Since 2018, UKCEH, with input from all partners, have been developing a method of using NPMS data to indicate annual changes in habitat condition. The method is based on a hierarchical model, formulated in a Bayesian framework, that integrates information on a species’ abundance and occupancy; the occupancy estimates also take advantage of the fact that most plots are surveyed twice a year, allowing adjustments for false negatives (i.e. species that are overlooked during surveys). Simulation tests and applications to real data indicate that the method is robust and produces ecologically sensible metrics.

The one-kilometre squares of the NPMS were selected according to a weighted-random algorithm designed to introduce a known bias towards semi-natural habitats. However, within this design, a sampling bias exists in that, in common with other UK structured monitoring schemes based on volunteer participation, squares located within lowland areas are more likely to be sampled. Further work will focus on additional adjustment for bias (Pescott et al., 2019b).

Until 2013, this indicator was based on analysis of the change in plant species richness in the wider countryside. Data were taken from the UK Countryside Survey. This survey provides a random sample of vegetation plots located in arable and horticultural fields, agricultural grasslands, woodlands and associated boundary habitats in Great Britain. Key messages from the previous indicator are presented here; although now archived, the indicator can also be viewed in full.

The indicator presented the change in plant species richness in survey plots across Great Britain between 1990 and 2007 for a range of widely occurring habitats. The results from 7 habitat types were grouped into 3 measures for the assessment: arable and horticultural land; woodland and grassland; and boundary habitats. The indicator compared species richness per plot for the exact same plots surveyed in 1990, 1998 and 2007. For each broad habitat type, the data were converted to an index (on a scale of 0 to 100) to compensate for the difference in plot size between habitats. In the long term (1990 to 2007) and short term (1998 to 2007), the change in plant diversity of arable and horticultural land was assessed as improving; whilst for woodland and grassland and boundary habitats the assessment in both the long and short term was declining (see Figure C7ii).

 

Figure C7ii. Plant species richness in the wider countryside, 1990 to 2007.

A bar chart showing the index of plant species richness in the wider countryside of Great Britain for 3 habitat types: arable land, woodland and grassland, and boundary habitats in 1990, 1998 and 2007.

Notes:

  1. * A statistically significant change between 1990 and 2007.
  2. ~ A statistically significant change between 1998 and 2007.

Source: UK Centre for Ecology & Hydrology, Countryside Survey.

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Goals and Targets

Aichi Targets for which this is a primary indicator

Strategic Goal C. To improve the status of biodiversity by safeguarding ecosystems, species and genetic diversity.

Aichi target 12 icon

Target 12: By 2020 the extinction of known threatened species has been prevented and their conservation status, particularly of those most in decline, has been improved and sustained.

Aichi Targets for which this is a relevant indicator

Strategic Goal B. Reduce the direct pressures on biodiversity and promote sustainable use.

Aichi target 5 iconTarget 5: By 2020, the rate of loss of all natural habitats, including forests, is at least halved and where feasible brought close to zero, and degradation and fragmentation is significantly reduced.

Aichi target 7 icon

Target 7: By 2020 areas under agriculture, aquaculture and forestry are managed sustainably, ensuring conservation of biodiversity.

 

Strategic Goal C. To improve the status of biodiversity by safeguarding ecosystems, species and genetic diversity.

Aichi target 11 iconTarget 11: By 2020, at least 17 per cent of terrestrial and inland water, and 10 per cent of coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem services, are conserved through effectively and equitably managed, ecologically representative and well connected systems of protected areas and other effective area-based conservation measures, and integrated into the wider landscape and seascapes.

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Reference Title 
Botanical Society of Britain & Ireland Home Page
Countryside Survey Home Page
Joint Nature Conservation Committee Home Page
National Plant Monitoring Scheme Home Page
Plantlife Home Page
UK Centre for Ecology & Hydrology Home Page

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References

Pescott, O.L., Walker, K.J., Harris, F., New, H., Cheffings, C.M., Newton, N., Jitlal, M., Redhead, J., Smart, S.M. and Roy, D.B. (2019a). The design, launch and assessment of a new volunteer-based plant monitoring scheme for the United Kingdom. PLoS ONE 14(4): e0215891. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0215891 

Pescott, O.L, Powney, G.P. and Walker, K.J. (2019b). Developing a Bayesian species occupancy/abundance indicator for the UK National Plant Monitoring Scheme. Wallingford, NERC/Centre for Ecology & Hydrology and BSBI, 29pp. DOI:10.13140/RG.2.2.23795.48161

Soldaat, L.L., Pannekoek J., Verweij, R.J.T., Van Turnhout, C.A.M. and Van Strien, A.J. (2017). A Monte Carlo method to account for sampling error in multi-species indicators. Ecological Indicators 81: 340–347 DOI:10.1016/j.ecolind.2017.05.033

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Downloads

Download the Datasheet and Technical background document from JNCC's Resource Hub.

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Last updated: October 2020

Latest data: 2019

 

This content is available on request as a pdf in non-accessible format. If you wish for a copy please go to the enquiries page.

 

Categories:

UK Biodiversity Indicators 2020

Published: .

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