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C4a. Status of UK priority species – Relative abundance

Type: State indicator

Indicator Description

This indicator shows changes in the relative abundance of priority species in the UK for which data are available. The relative abundance of each priority species in this indicator is the estimated population (abundance) of that species in the latest year of the time series taken as a percentage of its estimated population in the earliest year of the time series (i.e. the base year). The indicator will increase when the population of priority species grows on average and decrease when the population declines.

This indicator should be read in conjunction with C4b which provides data on those UK priority species for which distribution data are available.

Contents

  1. Summary
  2. Downloads

Summary

Official lists of priority species have been published for each UK country. There are 2,890 species on the combined list; actions to conserve them are included within the respective countries’ biodiversity or environment strategies. This indicator shows the average change in 214 species for which abundance trends are available.

By 2016, the index of relative abundance of priority species in the UK had declined to 40% of its base-line value in 1970, a statistically significant decrease (Figure C4a1). Over this long-term period, 22% of species showed a strong or weak increase and 63% showed a strong or weak decline.

Between 2011 and 2016, the index was 22% lower than its value in 2011, again showing a statistically significant decrease. Over this short-term period, 35% of species showed a strong or weak increase and 46% showed a strong or weak decline.

Figure C4ai. Change in the relative abundance of priority species in the UK, 1970 to 2016.

A line graph showing how the index of relative abundance of priority species in the UK has changed from 1970 to 2016. The index has fluctuated considerably from year to year but overall, by 2016 it had shown a statistically significant decrease to 40% of its base-line value in 1970. A 100% stacked bar chart showing the percentage of individual priority species in the UK that have increased (strongly or weakly), decreased (strongly or weekly) or remained unchanged in their relative abundance. The chart covers 2 time periods: over the long term (1970 to 2016), 22% of species showed a strong or weak increase and 63% showed a strong or weak decline; over the short term (2011 to 2016), 35% of species showed a strong or weak increase and 46% showed a strong or weak decline.

Notes:

  1. The line graph shows the unsmoothed trend (dashed line) with its 95% confidence interval (shaded area).
  2. The figure in brackets shows the number of species included in the composite index.
  3. The bar chart shows the percentage of species within the indicator that have increased (weakly or strongly), decreased (weakly or strongly) or shown no change in abundance based on set thresholds of change.
  4. 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).
  5. This indicator is not directly comparable with the previous publication. There have been a number of minor changes in the composition and a revision to the statistical methods used (see the indicator description section for more detail). 

Source:  Bat Conservation Trust, British Trust for Ornithology, Butterfly Conservation, Centre for Ecology & Hydrology, Defra, Joint Nature Conservation Committee, People’s Trust for Endangered Species, Rothamsted Research, Royal Society for the Protection of Birds.

Assessment of change in the relative abundance of priority species in the UK

 

Long term

Short term

Latest year

Priority species – Relative abundance


1970–2016


2011–2016

Decreased (2016)

Note: Analysis of the underlying trends is undertaken by the data providers.

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Downloads

Download the Fiche, Datasheet and Technical background document from the JNCC Resource Hub

Last updated: September 2019

Latest data:

Abundance data – 2016;

Combined long-term abundance and distribution data – 2015

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Categories:

UK Biodiversity Indicators 2019

Published: .

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