Szentes et al. (2012) Central European Journal of Biology

Szentes Sz., SutyinszkiZs., Szabó G., Zimmermann Z., Házi J., Wichmann B., Hufnagel L., Penksza K.,Bartha S.: Grazed Pannonian grassland beta-diversity changes due to C4 yellowbluestem. Central European Journal ofBiology 7(6): 1055-1065   DOI:10.2478/s11535-012-0101-9

Abstract

This study investigates how yellow bluestem affects biodiversity in a typical Pannonian grassland. Beta diversity (i.e. the finescale spatial variability of species compositions), was estimated by the realized number of species combinations sampled at various scales. Sampling was performed by a standard protocol. Presences of plant species were recorded along 52.2 m long belt transect of 1044 units of 0.05x0.05 m contiguous microquadrats. According to the results the massive presence of tested C₄ grass significantly reduced species richness of the grassland. Beta diversity assessment revealed that 90% of species combinations were lost due to yellow bluestem invasion. Fine-scale spatial pattern analyses showed complete local extinctions of other species from microsites dominated by yellow bluestem. This local extinction is enhanced by the specific clonal architecture of this species and by the accumulation of litter. Other dominant grasses had no effect on fine scale diversity, i.e. they could coexist well with other elements of the local flora. This study presents currently developed microhabitat types, forecasts and also draws attention to the danger that climate warming will probably enhance the spread of this detrimental C₄ species.

Keywords

Dominant grass, Plant neighbourhood diversity, Litter, Spatial association, Climate change

Miglécz et al. (2013) Plant Ecology

Tamás Miglécz, Béla Tóthmérész, Orsolya Valkó, András Kelemen, Péter Török (2012) Effects of litter on seedling establishment: an indoor experiment with short-lived Brassicaceae species. Plant Ecology, DOI: 10.1007/s11258-012-0158-6

Abstract

Recruitment by seeds is essential both in vegetation dynamics and in supporting biodiversity in grasslands. The recruitment by seeds is feasible in suitable vegetation gaps from the seed rain and/or by establishment from persistent soil seed banks. Cessation of grassland management results in litter accumulation, which leads to the decline of species diversity by the decreased availability of open patches. Low amounts of litter is often beneficial, while high amounts of litter is detrimental for seed germination and seedling establishment of short-lived species. In a designed indoor experiment, we explored the effect of litter on seedling establishment by germinating six short-lived Brassicaceae species with both increasing seed mass and litter cover. We found that both seed mass and litter had significant effect on germination and establishment of the sown species. Small-seeded species were significantly negatively affected by the 300 and/or 600 g/m² litter layers. No negative litter effect was detected for species with high seed masses (Lepidium spp.). No overall significant positive litter effect was found, although for most of the species cumulative seedling numbers were not the highest at the bare soil pots. Our results suggest that the negative effects of litter are less feasible on the large-seeded short-lived species than on that of small-seeded ones.

Keywords

Biodiversity, Cruciferae, Litter, Seed size, Germination, Weed control

Török et al. (2012) Ecological Engineering

Péter Török, Tamás Miglécz, Orsolya Valkó, András Kelemen, Katalin Tóth, Szabolcs Lengyel, Béla Tóthmérész (2012): Fast restoration of grassland vegetation by a combination of seed mixture sowing and low-diversity hay transfer. Ecological Engineering 44: 133-138.

Abstract

Technical reclamation of grasslands is a powerful tool for conserving biodiversity in fragmented landscapes. Plant material transfer and sowing seeds of local provenance are used most frequently to recover grassland vegetation in former croplands. The joint application of these methods is rarely used, although it has the potential to gain a predictable and directed vegetation development with effective early weed suppression. We studied the effectiveness of combining low diversity seed sowing and hay-transfer in weed suppression and recovery of perennial grassland vegetation in Hortobágy Puszta, Central-Europe, by testing the following hypotheses: (i) lower weed cover and biomass is expected in vegetation recovered by the joint method of sowing and hay transfer than by seed sowing only. (ii) With sowing and additional hay transfer a higher rate of establishment of Festuca species is expected than with sowing only. Our results supported both hypotheses. We found that the additional application of hay significantly accelerated the development of perennial grassland vegetation and provided a higher weed suppression rate in the first year and onwards in most plots than seed sowing only. A higher establishment rate was detected both in the cover and the biomass of perennial grasses including Festuca species in all plots with hay addition than with sowing only. Our results suggest that a combination of hay transfer and low diversity sowing may provide a cost-effective alternative to the more costly high-density sowing and if proper sources for high-diversity hay are available, it may replace high-diversity seed mixtures.

Keywords

Grassland restoration; Festuca; Biomass; Litter; Weeds; Mulch; Species richness