Monitoring the Finnish butterflies
A decline in the Finnish butterfly fauna, now comprising 122 species, has been indicated by several studies and reviews. For example, Marttila et al. (1991) evaluated that almost half of the indigenous species in Finland had suffered from changes in their environment since the 1970s. In 1976, the first butterflies to be protected by law were Parnassius apollo and P. mnemosyne. Nowadays a total of 17 butterfly species are under legal protection. In the latest evaluation of threatened species in Finland (2010), 43 butterfly species were classified as threatened or near threatened. In general, butterflies are regarded as one of the most endangered insect groups in Finland. Several factors have been implicated in the decline of butterflies, but the prime factor has been the alteration or complete destruction of the habitat.
The National Butterfly Recording Scheme in Finland (NAFI) was started in 1991. By providing quantitative knowledge of possible changes in the distribution and abundance of butterflies, NAFI was intended to be used to protect the Finnish butterfly fauna.
Field data in NAFI are based on observations of butterflies made by voluntary amateur and professional lepidopterists all over the country, marked on the form designed for the scheme. The information required includes the year, the Finnish uniform grid (100 km quadrat), the counted or estimated number of individuals of species observed, and the counted or estimated number of observation days. Since 2008 it has also been possible to enter butterfly data via the website of the Finnish Museum of Natural History.
So far (1991-2013) more than 750 voluntary lepidopterists have participated by providing data on more than 4.8 million individuals representing 113 species. The data covers 2,220 quadrats and is based on more than 135,000 observation days all over the country. The database of NAFI has been used in several studies and projects, for example in evaluation of the climate change. Main publications can be found here.
The official website for the scheme provides more detailed data, such as maps for individual species for each year.