Butterfly monitoring

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 the food-chain, providing food for other insects as well as birds and mammals.

Butterflies in Europe 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.

There are well organised schemes active in Europe in many countries, from Finland in the north to Spain in the south. The European Butterfly Monitoring Scheme (eBMS) was formed by Butterfly Conservation Europe in April 2016 to bring together data from these country schemes into a single database. The work is coordinated by the Centre for Ecology and Hydrology in the UK and has its own dedicated website.

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

• Belgium (Flanders): all species since 1991 from 10-20 sites.
• Estonia: all species on ten transects since 2004.
• Finland: all species since 1999 from appr. hundred sites.
• France (Doubs and Dordogne): all species since 2001 from ten sites.
• France (whole country): all species starting 2006, now appr. 600 sites.
• 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 hundred sites.
• Germany: Nordrhein-Westfalen all species since 2001. From 2005 data from over 100 sites available.
• Germany: In 2005 a nationwide monitoring scheme was launched, now hundreds of sites.
• Hungary: all species since 2016 with more than 30 transects
• Ireland: all species since 2007, more than 160 sites.
• Italy: all species since 2018.
• Jersey (Channel Islands): all species since 2004 from 25 sites.
• Luxembourg: all species since 2010.
• Portugal: new scheme in 2019
• Slovenia: all species since 2017
• Spain (Catalunya): all species since 1994 from 60-70 sites.
• Spain (Basque Country): all species since 2010.
• Spain (except Catalunya and Basque country): registering all species since 2014
• Sweden: all species since 2010, more than 100 sites.
• Switzerland (Aargau): all species since 1998 from over 100 sites.
• Switzerland: Also in the rest of the country butterfly monitoring data is collected since 2000, on at least 100 sites annually.
• The Netherlands: all species since 1990 on almost 800 sites.
• Transcarpathia (Ukraine): field data collected for all species at 20-30 sites since 1983, but at present only analysed for one species (Erynnis tages).
• United Kingdom: all species since 1976, annually from hundreds of sites.