Comparison of two methods for sampling orthopterans in grassland: differences in species representation and sex ratios

Abstract

Orthopterans are convenient indicators for threatened grassland ecosystems. Many sampling methods are known; amongthem, sweep netting is the most common. This study compares sweep netting with less common pan trapping and quantifies differencesin species representation and sex ratio between the two sampling techniques. Sampling took place in the submontane grassland inthe northeastern part of the Czech Republic (Central Europe) during July, August, and September 2010. Both sweep netting and pantrapping were used concurrently in 11 meadows. Sampled orthopteran adults were determined to the species level and their sex wasnoted. Both methods recorded the same pool of 14 species. A chi-squared test showed significant differences in representation of 7 out of8 analyzed species in sweep-net and pan-trap samples. Sex ratios also noticeably differed. Possible causes of the differences are discussed.This study showed that pan trapping is a solid alternative to sweep netting.