The latest results of the National Bat Monitoring Programme (NBMP) with data up to the end of summer 2019 are now available. Download the report here.
Last year over 1,000 dedicated volunteer citizen scientists carried out NBMP surveys at over 2,000 sites across the UK. The survey results allow BCT to estimate population trends for 11 out of the 17 species of bat which breed in the UK. At present we are not able to produce population trends for some of the rarer and more habitat-specialist bat species such as barbastelle or Bechstein’s bat as they are difficult to monitor or rarely encountered.
Results of the NBMP show that from the baseline year of monitoring (1999 for most species) to 2019, GB populations of the 11 species of bat surveyed appear to be stable or increasing. A few results need treating with caution and there are regional and/or country differences. Species considered to have increased in Great Britain since the baseline year of monitoring are greater horseshoe bat, lesser horseshoe bat, Natterer’s bat and common pipistrelle, all of which often use buildings to roosts in. The population trend for Natterer’s bat should be treated with caution until the effect of this species' roost switching behaviour on the Roost Count trend is better understood.
These encouraging results reflect relatively recent changes in bat populations. It is generally believed that during the early 20th century there were declines in bat populations. Possible drivers of the historical declines include agricultural intensification, loss of roosting and foraging habitat, persecution, pesticides and biocides including the use of toxic timber treatment chemicals within roosts, water quality, declines in insects, unsympathetic development, land-use change and climate change.
When they were our featured charity Bat Conservation Trust wrote about the National Bat Monitoring Programme for CJS Weekly, read this article here, (first published February 2016)