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Species Population Trends for Great Britain

Summary of species trends for Great Britain

This page provides a summary of the population trends at GB-level for species monitored by the NBMP. For a summary of the results of the country-level trends for England, Scotland and Wales, click here.

The table below shows the smoothed population indices derived from NBMP data in Great Britain to the end of 2016. For each species, the number of sites contributing to the 2016 trend calculations is shown as well as an approximation of the average annual percentage change in the index since the baseline year. It should be noted, however, that the average annual percentage change makes assumptions about the data analysis, and is only genuinely appropriate for those species for which the trend line appears to be linear.

Click on the species names in the following table to access information on:

  • The species population trends for GB and information at country or regional level where data are available
  • Graphs showing the trends calculated from each survey
  • The surveys that provide data for that species
  • Information on the distribution and abundance of the species

For the remaining UK bat species (Bechstein's bat, Alcathoe bat, Leisler's bat, Nathusius' pipistrellebarbastellegrey long-eared bat and greater mouse-eared bat) there are insufficient data available at present to allow calculation of population trends.

Information about the factors that affect our bat populations can be found here

GB bat species population trends summary table

Species 

Survey

No. sites trend analysis 

Base year

Long-term trend (since base year) %

Average annual change %

Greater horseshoe bat 

Hibernation

Roost Count

201

32

1999

1999

162.7*

145.3*

5.8

5.4

Lesser horseshoe bat 

Hibernation

Roost Count

300

294

1999

1999

158.0*

80.4*

5.7

3.5

Daubenton's bat

Hibernation

Waterway 

399

848

1999

1999

47.7*

1.6

2.3

0.1

Whiskered/Brandt's bat

Hibernation 

231

1999

38.5

1.9

Natterer's bat

Hibernation

Roost Count

506

82

1999

2002

66.4*

-3.1

3.0

-0.2

Common pipistrelle 

Field

Roost Count

626

489

1999

1999

82.1*

-58.0*

3.6

-5.0

Soprano pipistrelle

Field

Roost Count

626

377

1999

1999

 58.9*

-52.0*

 2.8

-4.2

Noctule

Field

626

1999

 27.6

 1.5

Serotine

Field

Roost Count

432

96

1999

1999

7.2

-19.9

0.4

-1.3

Brown long-eared bat

Hibernation

Roost Count

427

158

1999

2001

-31.3 *1

20.1

-2.2

1.2

Notes: 

* indicates significant result at 5%

Bold indicates which trend is considered to be most statistically robust if two trends are produced.

1For brown long-eared bat the Hibernation Survey shows a marginally significant decline in the most recent year when compared to the baseline year. Given the provisional nature of estimates for the most recent year, the small margin of significance and the fact that this margin is likely to change when additional years of monitoring data are added to the trend, there is not yet sufficient certainty to assess the population as declining.

Trends in context: 

These trends reflect relatively recent changes to bat populations since the 1990s. It is generally considered that prior to this there were significant historical declines in bat populations dating back to at least the start of the 20th century, although evidence is fragmented and few data were collected in a systematic way.

Information about the factors that affect our bat populations can be found here


 

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