Effects of montane heathland rejuvenation on phytodiversity depend on management intensity and succession

Abstract

Heathlands are of high importance for biodiversity conservation, and most heathlands depend on management. While the effects of management on biodiversity are well-studied for lowland heathlands, studies on Central European montane heathlands are scarce. Therefore, we analysed the effects of heathland rejuvenation measures on soil characteristics and phytodiversity within Central European montane heathlands. We focused on four heathland types: sod-cut heathlands with (i) early-successional stages (SOD CUT-EARLY) and (ii) midsuccessional stages (SOD CUT-MID), (iii) choppered heathlands with mid-successional stages (CHOP-MID) and (iv) late-successional heathland stages (CONTROL). For every heathland type, ten vegetation releve ` s were carried out. In every releve `, we analysed the cover of all vascular plant, bryophyte and terricolous lichen species. Additionally, soil characteristics were measured. Statistical analyses included generalised linear mixed-effects models and non-metric multidimensional scaling. Our study revealed that rejuvenation of montane heathlands reduced soil nutrient levels, increased pH values and had positive effects on phytodiversity. The effects of rejuvenation were persistent. Even after around 20 years following the measures, SOD CUT-MID and CHOP-MID were characterised by lower nutrient levels and different plant assemblages compared to CONTROL. Sod cutting and choppering promoted the rejuvenation of Calluna vulgaris, one target species of montane heathlands. However, the regeneration of Vaccinium vitis-idaea - another ericaceous target species - was clearly favoured by choppering in comparison to sod cutting. By contrast, overall vascular plant species diversity as well as the number of threatened vascular plant and target species were favoured by sod cutting in the long run while early-successional stages after sod cutting had positive effects on lichen diversity. Due to the contrary effects of the two rejuvenation measures, we recommend a spatial mix of high-intensity (sod cutting) and less intensive (choppering) rejuvenation methods in montane heathlands.