No species showing positive trends in 2021
The Annual Report for the Irish Butterfly Monitoring Scheme has been published and can be found here. In line with 2020 results, the multi-species index (pictured below) showed that once again there was a moderate decline (-35%) in the number of butterflies flying in 2021 when compared the baseline year of 2008.
Figure 1. The multi-species index derived from the amalgamation of the population trends of 15 common species of butterflies from 2008 to 2021.
When it comes to the individual species trends, no species showed an ‘increasing’ trend in 2021 and only 2 species showed a ‘stable’ trend (Peacock and Brimstone). Six species showed moderate declines in populations from 2008, and 7 species showed ‘strong declines’ including the Ringlet (-88%) and Meadow Brown (-86%). It is very important to note that the analysis used to generate the results changed slightly this year and this should be taken into account when interpreting results. A full explanation what changes were made and why can found in the Annual Report.
Established in 2008, the Irish Butterfly Monitoring Scheme has been tracking change in butterfly populations for 14 years. The scheme was established because butterflies are sensitive to changes in their environment making them good indicators of land-use and climate change. It is the longest running insect monitoring scheme in Ireland and managed by the National Biodiversity Data Centre. It involves volunteers walking a fixed route (transect) each week when weather conditions are favourable counting all the butterflies seen. It is a huge voluntary effort by citizen scientists, with 88 transects walked by 69 volunteers counting 27,900 individual butterflies. Unfortunately there are not sufficient sites monitored of our rarer or localised species to enable their populations to be tracked.
Read the detailed analysis in the Annual Report.
