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QUESTIONS: Sod cutting has been used extensively as an effective measure in removing excess N and restoring dwarf shrub dominance in heathlands affected by increased nitrogen deposition. However, recovery of other plant species is often very limited. One barrier is high soil acidity following sod cutting, which results in soil aluminium (Al³⁺) and ammonium (NH₄⁺) reaching toxic concentrations. Sod‐cutting management also removes most of the major nutrients from the system, so intensified nutrient limitation could be an additional barrier to the recovery of species‐rich communities. Soil phosphorus (P) is of special interest as research indicates sod‐cutting management can shift the system to P limitation. LOCATION: Hoge Veluwe National Park, The Netherlands. METHODS: We set up a full‐factorial experiment in sod‐cut heathland formerly encroached by Molinia caerulea, adding phosphate (P+) and lime (Ca+) and over the next three growing seasons, we recorded soil chemistry and plant responses. RESULTS: Soil inorganic N, especially soil NH₄⁺, strongly declined after liming compared to the control situation, confirming that liming alleviates NH₄⁺ toxicity. Addition of P resulted in a similar decline, also suggesting a role for soil phosphate availability in this process. Acid‐sensitive plant species richness increased significantly in both Ca+ and P+ treatment, whereas acid‐insensitive plant species richness only increased significantly as a result of P+ treatment. Mean vegetation relative growth rate increased significantly in both Ca+ and P+ treatments. CONCLUSIONS: Excessive P removal due to sod cutting constitutes a second barrier to restoration in addition to soil acidity. We discourage the large‐scale use of sod cutting to reduce soil N availability in heathlands and propose to use interventions that leave the soil nutrient balance intact, such as burning and grazing, mowing or litter removal, in combination with measures that restore the soil buffer capacity.

Background and aims – Common juniper (Juniperus communis L.) is one of the most widespread woody species on the planet. Over recent decades, however, common juniper populations are decreasing in size and number in different regions. Lack of recruitment, caused by extremely low seed viability and the absence of suitable microsites for recruitment, is the key reason for this decline. For successful germination, the seeds need gaps in the existing vegetation and a soil with a relatively high base saturation. The aim of this study was therefore to assess how management actions such as sod cutting, rotavation and liming (alone or in various combinations) influence soil characteristics, seed germination and seedling survival of common juniper.Methods – We installed a sowing experiment across 104 1-m2 plots in four different sites in Belgium and the Netherlands using treatments with different combinations of fencing, sod cutting, rotavation, litter addition and liming. We determined how these treatments affected soil characteristics and how they influenced seed germination and seedling survival.Key results and conclusions – Across the whole experiment, germination rates of juniper seeds were very low (almost always < 1%). Our results confirm that bare ground promotes the germination of juniper seeds. Secondly, higher silt and lutum (clay) proportions in the soil and higher soil organic matter content seemed to have a positive impact on recruitment, possibly due to drought reduction. Management actions that negatively affect those soil characteristics, such as deep sod cutting, should thus be avoided in heathlands on sandy soils. Our results reveal a complex relationship between seedling recruitment success, soil conditions and management of common juniper populations. Overall, combinations of fencing, (superficial) sod cutting and liming or rotavation were most successful.

The effects of sod cutting were studied in a dune area on the Dutch Wadden Sea Island of Texel. Sod cutting was carried out in a range of different dune slacks in order to restore dune slack vegetation with many endangered Red List species. Sod cutting removed approximately 96% of the soil seed bank. Species abundant in the seed bank, notably Juncacea, also had a high frequency in the vegetation that established during the first year after the restoration measures. Many other species not registered in the seed bank or in the former vegetation also appeared. Species richness in the monitored plots exceeded that of uncut reference plots after a few years. Colonization rates were higher than extinction rates in most plots, indicating that a stable state has not been reached after 5 years. Differences in species richness between slacks appeared to be related to the occurrence of source areas nearby and availability of dispersal agents, such as flooding and animals.

The negative impact of grass and moss encroachment on the botanical diversity of West European coastal dunes attracted increasing attention in the 1990s. This paper focuses on moss encroachment during primary succession in the xeroseries. Until the mid-1970s, vegetation types rich in species of the lichen genera Cladonia and Cladina were found on the fixed. Corynephorus canescens-dominated, so-called grey dunes all over the island of Terschelling, The Netherlands. In addition, species of Hypogymnia, Parmelia and Usnea, which usually grow on trees, occured here terrestrially on moss carpets or bare sand. These vegetation types are still present on the Noordsvaarder, a nature reserve in the western part of the island. They occur on parts of seven dune ridges parallel to the coast and form a chronosequence in which age increases with distance from the sea. Our study found the highest lichen diversity on the second and third dune ridges in a stage of primary succession that can be assigned to the Violo-Corynephoretum. The changes from lichen-rich to moss-dominated stadia were significantly related to soil development and acidification in connection with the ageing of the dune soil. The superficial cutting of sods in moss-encroached vegetation appeared to be unsuccessful as a management technique for restoring the biodiversity of cryptogams. Our findings suggest that the best option for maintaining lichen vegetation in the Violo-Corynephoretum is the blow-in of sand with a subneutral or neutral pH from reactivated and natural blowouts or from foredunes, with increasing lime content respectively.

Verdroging van veengronden is een veel voorkomend verschijnsel in beekdalen. Hoewel hydrologisch herstel een eerste vereiste is, zijn aanvullende maatregelen wenselijk. In deze obn bijdrage wordt verslag gedaan van ervaringen met het plaggen in De Lage Maden (Drentse Aa), De Barten (Linde) en De Wyldlannen (lage midden, Friesland)

In dit proefschrift worden de mechanismen geanalyseerd die de effectiviteit bepalen van enkele hydrologische maatregelen en plaggen op het herstel van soortenrijke, natte schraalgraslanden. Het veldonderzoek werd gedaan in de Bennekomse Meent en het Korenburgerveen. Voorafgaand is oriënterend (eco)hydrologisch onderzoek gedaan in het zuidelijk deel van de Gelderse Vallei

In dit proefschrift worden de mechanismen geanalyseerd die de effectiviteit bepalen van enkele hydrologische maatregelen en plaggen op het herstel van soortenrijke, natte schraalgraslanden. Het veldonderzoek werd gedaan in de Bennekomse Meent en het Korenburgerveen. Voorafgaand is oriënterend (eco)hydrologisch onderzoek gedaan in het zuidelijk deel van de Gelderse Vallei