C4. Status of UK priority species
C4b. Distribution
Type: State Indicator
Indicator Description
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This indicator measures change in the number
of 1km grid squares across the UK in which priority species were
recorded in any given year. This is referred to as the ‘occupancy
index’ and is effectively equivalent to changes in the distribution
of priority species for which data are available. The
indicator will increase when priority species become more
widespread on average, and decrease when species becomes less
widespread. This indicator should be read in conjunction with
C4a which provides
data on those species for which abundance information is
available
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Summary
No new data since the previous publication, however a combined
evaluation of the long-term change in the relative abundance
and distribution of priority species (C4a and C4b) has been added to
the background section of this update.
Official lists of priority species have been published for each
UK country. There are 2890 species on the combined list; actions to
conserve them are included within the respective countries’
biodiversity or environment strategies.
Between 1970 and 2016, the index was relatively stable; there
was an even balance of species increasing and decreasing in
distribution and the 5% long-term increase was not statistically
significant.
The index was 3% higher in 2016 than in 2011, with 39% of
species showing an increase and 35% showing a decline. Once again,
however this short-term increase was not significant.
Figure C4bi. Change in distribution of
UK priority species, 1970 to 2016.
Notes:
- Based on 714 species. The graph
shows the unsmoothed composite indicator trend (dotted line) with
variation around the line (shaded) within which we can be 90%
confident that the true value lies (credible interval).
- The bar chart shows the percentage of
species within the indicator that have increased, decreased or
shown no change in distribution (measured as the proportion of
occupied sites), based on set thresholds of
change.
- All species in the indicator are
present on one or more of the country priority species lists
(Natural Environmental and Rural Communities Act 2006 –
Section 41 (England), Environment (Wales) Act 2016 section 7,
Northern Ireland Priority Species list, Scottish Biodiversity
List).
- As a result of methodological improvements in the
occupancy model analysis, a greater number of taxonomic groups and
species have been able to be included compared to the 2015 C4b
indicator. Therefore, this chart is not directly comparable
to previous versions of the indicator.
Source: Biological records data
collated by a range of national schemes and local data
centres.
Assessment of change in distribution of priority species
in the UK
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Long term
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Short term
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Latest year
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Priority species – Distribution
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 1970–2016
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2011–2016
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Increased (2016)
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Download Fiche
Download Datasheet
Download Technical background
document
Download Technical
background document on Bayesian Occupancy Models
Download
Evidence statement
Last updated: July 2018
Latest data: 2016