Aims & approach

Aims

The main aim of Monitoring Scheme is to obtain from transects objective information about butterfly species abundance and their changes in time. It is important for conservation purposes and understanding of butterfly ecology to have large datasets. Individual transect counts serve as basic level for the next aim, which is integration of results from individual sites to a wider combined picture of changes in butterfly species abundance. The analysis and data interpretation of this information base about local distribution of butterflies, site colonization, extinction and migration, flight periods may be added to the original aims.

The monitoring method

In Britain Butterfly Monitoring Scheme transect routes are divided into maximum of 15 sections with total length close to 3 km (Pollard, Yates, 1993). The difference from British Scheme is that in Monitoring Scheme in the East Slovakia transect includes 20 sections of 50 m each. This will achieve advantages such as: separate counts, which have to be made on each section, so that attempts can be made to compare butterfly indexes of equal areas and produce conclusions about local distributions of butterflies. The experience of monitoring walks suggests, that 1 km length is close to optimum, although there are samples vary in the length of transect routes in different national schemes. Another important transect parameter is section's width. In practice, the precise width of section is designated by the recorder and never changed, if it already adopted. On average mean width of the transect adopted was 5 m. For instance, a ride might go through woodland and has clear defined 5-6 m width grassy tracks with small scrub edges or young trees and it is ideal for butterfly recording. Frequently woodland transects include landscape features such as banks, ditches alternating with wide forest glades. Following this diversity, the butterfly counts will reflect the peculiarities of each section of habitat. So the number of butterflies recorded in a narrow belt of vegetation might be higher than in wide ride in forest clearance. This last comment becomes important when new transect are designated for future detailed comparative butterfly counts. The best advice on how to count the butterfly species is imagine moving with a 5 m sided box in front of observer and record individuals seen. To record butterfly adults or larvae sitting on substrates, flowers or grass does not require special effort and gives good results. Such canopy species as Apatura iris, A. ilia, Limenitis camilla, L. populi, Quercusia quercus, Strymonidia w-album or Thecla betulae can be recorded, when they are at alow level and sitting on wet ground to drink water. The recorder should count all butterflies while walking along the transect at a steady pace. Sometimes it will be useful to make a special effort to see a specialist species in dense vegetation. If the recorder meets with the same individual butterfly it is best not include it in the transect counts. But, if unsure it records again.

Each recording period continues from 1st of April to 29th of September. In high altitudes it starts later, after vegetation and day temperature become suitable. Normally, at least one recording walk should be done in each recording week. Overall the season includes 26 weeks, but some of this can be missed by case of bad weather conditions, illness of recorder and holidays.