Butterfly Monitoring

Butterflies are one of the most popular and well-known groups of insects. By monitoring their trends, they can serve as useful biological indicators, not only of other insects but also the health of the environment in which we all live. Butterflies started to be monitored in Europe in the 1970s and are one of the best-monitored insect groups in the world. However, there are still gaps in our knowledge which BC Europe aims to fill by promoting butterfly monitoring in Europe and in countries around the world.

The European Butterfly Monitoring Scheme (eBMS)

The eBMS was started by Butterfly Conservation Europe in April 2016 to bring together data from the Butterfly Monitoring Schemes from different countries into a single database. The work is coordinated by the UK Centre for Ecology and Hydrology.

There are well organised schemes active in Europe in many countries, from Finland in the north to Spain in the south. The data from all these schemes is collated into a single large database to analyse and produce the population trends of European species. It is also used to produced combined indicators such as the Grassland Butterfly Indicator which is used to assess the state of Europe’s biodiversity (see page 269).

Butterflies have been counted by Butterfly Monitoring Schemes since 1976. The method consists of counting butterflies along a fixed route called a transect which is visited regularly during the butterfly flight period (the exact period depends on the country). Most transects are counted once per week by volunteer recorders. More recently 15-minute counts have been added that can be used to monitor rare species as well as remote sites where regular butterfly transects are unrealistic.

Data can be submitted online or by using the ButterflyCount app.

Further details can be found on the eBMS website.

Why do butterflies make good bioindicators?

Butterflies are valuable bioindicators of terrestrial ecosystems because they meet a series of requirements:

1. They are easy to recognize.
2. They are very sensitive to changes (both climatic and actions in their habitats).
3. They are a prominent group of insects that collectively make up more than two-thirds of all species on Earth.
4. Together with other insects, they are a vital component of food-chains, providing food for other insects as well as birds and mammals. In addition, the pollination of many wild flowers and crops depends on insects.

Projects Boosting Butterfly Monitoring

Butterfly Conservation Europe has been working on several projects to promote and improve butterfly monitoring in Europe. Discover more in the following links:

EPIC EMBRACE SPRING ABLE

Butterfly Trends

One of the main reasons for doing butterfly monitoring is the possibility of calculating butterfly trends. They show whether certain species, groups of species or species (groups) within regions are declining or not. Those trends are calculated from the robust data provided each year by the numerous butterfly monitoring schemes (BMS). Butterfly trends show the status of individual butterfly species and by combining trends from many species, we can calculate butterfly indicators for certain habitats, such as the Grassland Butterfly Indicator. Some BMS publish the trends of butterflies as a part of the annual report (see above).

Countries running their BMS for several years can calculate their trends specifically for their countries and climate. Trends can be seen in the reports found in the links below.

Butterfly Indicators

You can find out more about the indicators produced using butterfly monitoring data using the following links:

• Butterfly Indicators 2018
• Butterfly Indicators: Grassland species 1990-2020 (2.01 MB )

Butterfly Monitoring Schemes in Europe

Butterfly monitoring is booming. Since the start in the UK in 1976 more and more schemes have joined in. At present the following schemes are active in Europe (click the links for more info):

1. Andorra: all species since 2004 (inside CBMS).
2. Austria- AUBMS: new scheme in 2019, more than 30 transects.
3. Austria (Viel-Falter): all species since 2013.
4. Belgium (Flanders): all species since 1991 from 10-20 sites.
5. Belgium (Wallonie): all species since 2010.
6. Croatia all species since 2020, more than 30 transects.
7. Cyprus: new scheme since 2019.
8. Bulgaria: new scheme in 2019.
9. Czech Republic: monitoring all species since 2014.
10. Estonia: all species on ten transects since 2004.
11. Finland: all species since 1999 from approximately 100 sites.
12. France (Doubs and Dordogne): all species since 2001 from 10 sites.
13. France (whole country): all species starting 2006, now approximately 600 sites.
14. Germany: in the Pfalz region monitoring data on three habitat directive species (Maculinea teleius, M. nausithous and Lycaena dispar) is available since 1989 from almost a hundred sites.
15. Germany: Nordrhein-Westfalen all species since 2001. From 2005 data from over 100 sites available.
16. Germany: In 2005 a nationwide monitoring scheme was launched, now 100 of sites.
17. Hungary: all species since 2016 with more than 30 transects.
18. Ireland: all species since 2007, more than 160 sites.
19. Italy: all species since 2019, more than 100 transects.
20. Jersey (Channel Islands): all species since 2004 from 25 sites.
21. Latvia: all species since 2015.
22. Lithuania scheme restarted in 2021, with some transects from 2009.
23. Luxembourg: all species since 2010, more than 80 transects.
24. Malta: all species since 2020.
25. Norway: all species since 2009 (including bumblebees).
26. Poland: all species since 2020.
27. Portugal: new scheme in 2019, more than 40 transects.
28. Slovenia: all species since 2007.
29. Spain (Catalunya): all species since 1994 from 159 sites.
30. Spain (Basque Country): all species since 2010.
31. Spain (except Catalunya and the Basque country): registering all species since 2014, more than 200 sites.
32. Sweden: all species since 2009, more than 100 sites.
33. Switzerland (Aargau): all species since 1998 from over 100 sites.
34. Switzerland: Also in the rest of the country butterfly monitoring data is collected since 2000, on at least 100 sites annually.
35. The Netherlands: all species since 1990 on >1000 sites.
36. Transcarpathia (Ukraine): field data collected for all species at 20-30 sites since 1983, but at present only analysed for one species (Erynnis tages).
37. United Kingdom: all species since 1976, annually from >3000 sites.
38. Turkey: all species since 2022.