S. Mahunka szerk.: Folia Entomologica Hungarica 52. (Budapest, 1992)

Community structure parameters can be seen on Table 1. The biggest species number was found on the steppe meadow (C) (27 species). On the other three sites, where the habitat was more open, species number was lower, varying between 13 and 16. The average density of grasshoppers was 47.67 individuals per transect. The lowest density was measured in the closed grassland (D) (35.50), and the highest in the ecotone zone (B) (61.62). The diversity value was greatest on the steppe meadow (C) (2.259). The calculated diversity values for sites (A), (B), and (D) were similar to each other, but these values were much lower than that of the site (C) (1.057, 1.369, and 0.902, respectively). In each plant association Glyptobothrus was the dominant genus. According to the dominance values of Glyptobothrus (Table 1), the study sites can be ordered as: (C)<(B)<(A)<(D). The most dominant species (not including the Glyptobothrus genus) have low dominance indices in each case. In the closed grassland (D) Rhacocleis germanica (0.04), in the open grassland (A) Oedipoda coerulescens (0.10), in the ecotone zone (B) Oe. Coerulescens (0.25), and in the steppe meadow (C) Stenobothrus crassipes. (0.28) were the most dominant species of the sites. Sites can be arranged according to structure parameters in the following increasing order: diversity : (D) < (A) < (B) < (C) dominance : (C) <(B) < (A) <(D) plant cover : (A) <(B) <(C) <(D) Excluding the only north-facing closed habitat (D), diversity and plant cover values changed in a similar manner, while dominance changed inversely with plant cover. Although the grasshopper communities of the different plant associations compared with each other showed high similarity in species composition, but according to the BrayCurtis index they were fundamentally different in terms of species abundances. The Orthoptera community of the ecotone zone (B) showed the highest similarity to the open habitat (A). Only slightly smaller values were found between the open habitat (A) and the closed grassland (D), moreover, between the ecotone (B) and the closed grassland, too. There is a relevant difference between the composition of these three communities and that of the (C) site (Table 2). Table 2. Comparison of the study sites based on the Bray-Curtis index. (A) =open grasslands, (B) = ecotone zone, (C) =steppe meadow, (D) = closed grasslands. (-H-=strong similarity, +=weak similarity) sites (A) (B) (C) P) (A) X + + + (B) 0.84 X + + (C) 0.36 0.31 X + P) 0.74 0.74 0.41 X