Monitoring of butterflies in semi-natural grasslands: diurnal variation and weather effects
2009 (English)In: JOURNAL OF INSECT CONSERVATION, ISSN 1366-638X, Vol. 13, no 2, 203-211 p.Article in journal (Refereed) Published
The butterfly fauna was monitored in six semi-natural grasslands in southeastern Sweden. The aim was to evaluate monitoring criteria for wind, sunshine, temperature and time of day for butterfly species richness and abundances when using the line transect method. A total of 30,111 butterflies belonging to 46 species were recorded. Data from this study suggests somewhat stricter criteria for temperature and sunshine than stated in the widely used "Pollards walk". A sharp decline in butterfly numbers were detected at temperatures below 19A degrees C if the proportion of sunshine of the transect walk was below 80-85%. No effect of wind speed, up to five on the Beaufort scale, on observed numbers of species or individuals were found. Several butterfly species showed well-defined diurnal rythms of flight activity, and the results indicated that transect walks can be performed between -4.5 and +4 h from the time when the sun reached its highest point. The results of this study can be used to adjust general criteria in national monitoring and also for detailed regional and local monitoring where it may be important to adjust for diurnal rhythm and weather related bias.
Place, publisher, year, edition, pages
2009. Vol. 13, no 2, 203-211 p.
Lepidoptera, Line transect method, Species richness, Weather conditions
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-17282DOI: 10.1007/s10841-008-9144-7OAI: oai:DiVA.org:liu-17282DiVA: diva2:208138
The original publication is available at www.springerlink.com:
Linnea Wikstroem, Per Milberg and Karl-Olof Bergman, Monitoring of butterflies in semi-natural grasslands: diurnal variation and weather effects, 2009, JOURNAL OF INSECT CONSERVATION, (13), 2, 203-211.
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