Comparative study of ground beetle and ground-dwelling spider assemblages of artificial gap openings

Artificial gap openings cause significant changes in vegetation structure (in every forest level), thereby greatly influencing arthropod communities. Our study compared the data of two common forest floor arthropod groups, ground beetles (Coleoptera: Carabidae) and ground-dwelling spiders (Araneae) from two artificial gaps situated in a turkey oak forest. Our surveys were carried out in the Gyöngyös-plain, in Hungary. Sampling of the arthropod communities was done with pitfall traps arranged in two 70 m long transects, along the longitudinal axis of the gaps, with 15 traps in each transect, 5 m from each other. We measured the quantity and quality of the deadwood lying around within a radius of 2.5 m of each trap. We observed that the species and numbers of spider specimens were higher in the inner parts of the transects (in the gaps), while the numbers of ground beetle specimens declined in the same traps. Furthermore, the Shannon and Simpson diversity values of the ground beetles were generally lower than those of the spiders. The ordinations showed a distinct influence of the gaps on the communities. The numbers of specimens of exclusively edge-associated species were also higher in the gaps. The correlation analysis indicated significant positive correlations between the number of ground beetles and spiders and the quantity of deadwood. In addition, there were significant negative correlations between the numbers of species of both groups and the rate of decay of deadwood

A fűrészlábú szöcske (Saga pedo) előkerülése kisalföldi homokpusztagyepben

Abstract: Predatory Bush Cricket is one of the largest and most characteristic Orthopteran species of Europe. The main habitats of the species are natural mosaics of steppe grasslands, low scrubs and open rocky grasslands occurring between 200 and 400 m a.s.l. Occurrences of Saga pedo on flatlands are very rare. This paper reports about finding specimens of the species in open sandy grassland of Little Hungarian Plain (~100 m a.s.l.). This is the second known population in Hungary and third population in the Carpathian Basin of Saga pedo which have been found in flatland sandy grasslands