Novel methods of heathland management promote grasshopper diversity and abundance

Today, the remaining heathlands suffer from habitat degradation, particularly due to unsuitable or absent management. Recently, two novel measures have been implemented to rejuvenate heathlands: moss removal (scarification) and disc harrowing. Here, we studied the effects of five different types of heathland management on Orthoptera (hereinafter referred to as grasshoppers): (i) prescribed burning (BURN), (ii) prescribed burning and subsequent disc harrowing (BURN+DIS), (iii) mowing (MOW), (iv) mowing and subsequent scarification (MOW+SCA) and (v) unmanaged old heathlands (CONTROL). Our study revealed strong differences in habitat structure, and in both species richness and density of grasshoppers between the management types. This was particularly true for CONTROL on the one hand, and BURN + DIS and, to a lesser extent, MOW + SCA on the other hand. CONTROL was dominated by tall stands of dwarf shrubs and had the lowest habitat heterogeneity. MOW + SCA exhibited the shortest swards and had the highest cover of bare ground. Although the cover of bare ground was also high and the turf was also short, BURN + DIS was characterised by the highest habitat heterogeneity. The number of species and density peaked in BURN + DIS, reached the second highest values in MOW + SCA, and were lowest in CONTROL. The application of the two novel heathland management techniques fostered habitat quality for grasshoppers by (i) strongly increasing the cover of bare soil, (ii) creating warm microclimatic conditions, (iii) boosting the availability of food resources, and (iv) favouring heterogeneity. Accordingly, we recommend both management techniques as regular measures to foster grasshoppers in heathlands.