Deák et al. (2015) Ecological Complexity

Deák, B., Valkó, O., Török, P., Kelemen, A., Tóth, K., Miglécz, T., Tóthmérész, B. (2015): Reed cut, habitat diversity and productivity in wetlands. Ecological Complexity 22: 121-125.

Highlights

• We tested the effects of winter cutting versus abandonment on wetland diversity.
• Winter cutting decreased habitat diversity and structural heterogeneity.
• Unmanaged wetlands harboured high amount of biomass in heterogeneous distribution.
• Diversity of vegetation types correlated positively with all biomass fractions.
• Intensive reed cut decreases wetland diversity by overriding edaphic conditions.

Abstract
There is a conflict between nature conservation and thatching industry regarding the management of reedbeds. On one hand, reedbeds are of an economical importance by providing thatching material, on the other hand, they harbour several endangered species. Reedbeds are typically managed by winter cutting, but its impacts on biodiversity are poorly understood. Our aim was to study the effects of winter cutting on the habitat diversity and structural heterogeneity of wetlands in a lowland alkali landscape (East-Hungary). We tested the following hypotheses: (i) Both diversity of plant species and habitat diversity are lower in winter cut wetlands compared to unmanaged stands. (ii) The distribution of biomass (green biomass, litter and standing dead biomass) is more homogeneous in winter cut wetlands compared to unmanaged ones. We found that winter cutting decreased habitat diversity and structural heterogeneity at multiple scales. Number of plant species and all measures of habitat diversity (number of patches, vegetation types and the length of vegetation margins) had lower scores in cut wetlands than in unmanaged ones. We found that unmanaged wetlands harboured high amount of accumulated biomass and they also maintained high habitat diversity likely due to the heterogeneous distribution of the biomass. In unmanaged wetlands, biomass accumulation did not decrease habitat diversity and also contributed to a higher structural heterogeneity. In cut wetlands, expansion of reed was an important driver of the decrease in habitat diversity and structural heterogeneity. Reed expansion likely overrode fine-scale edaphic conditions (hydrology and salinity) in shaping vegetation patterns; thus we suggest to avoid intensive winter cutting.

Keywords
Biomass, Landscape, Management, Margin, Marsh, Phragmites

Kelemen et al. (2015) Ecological Complexity

András Kelemen, Péter Török, Orsolya Valkó, Balázs Deák, Katalin Tóth, Béla Tóthmérész (2015): Both facilitation and limiting similarity shape the species coexistence in dry alkali grasslands. Ecological Complexity 21: 34–38. doi:10.1016/j.ecocom.2014.11.004

Abstract
Facilitation is an important driver of community assembly, and often overwhelms the effect of competition in stressed habitats. Thus, net effect of biotic interactions is often positive in stressed grasslands, where dominant species and litter can protect the subordinate species. Besides facilitation, niche partitioning can also support species coexistence leading to limiting similarity between subordinate species. Our aim was to provide a detailed analysis of fine-scale biotic interactions in stressed alkali grasslands. We supposed, that there are positive relationships between the main biomass fractions and species richness. We expected the expansion of trait ranges and the increase of trait dissimilarity with increasing biomass scores (total litter, green biomass of dominant species) and species richness. We studied the relationships between main biomass fractions, species richness, functional diversity and functional trait indices (ranges, weighted means and Rao indices). We used fine-scale biomass sampling in nine stands of dry alkali grasslands dominated by Festuca pseudovina. The detected relationships were always positive between the main biomass fractions (green biomass of dominant species, total litter and green biomass of subordinate species) and species richness. We found that the green biomass of dominant species and total litter increased ranges and dissimilarity of functional traits. Our results suggest that in dry alkali grasslands facilitation is crucial in shaping vegetation composition. The green biomass of dominant species and total litter increased the biomass production of subordinate species leading to overyielding. We found that mechanisms of facilitation and limiting similarity were jointly shaping the species coexistence in stressed grasslands, such as alkali grasslands.

Highlights

• We proposed a model of fine-scale biotic interactions in stressed alkali grasslands.
• Trait-based analyses are used to reflect fine-scale species co-existence patterns.
• Diversity and biomass of subordinate species increased by Festuca biomass and litter.
• Festuca increased the ranges and dissimilarity of functional traits.
• Facilitation and limiting similarity jointly shape species coexistence.

Keywords
Abiotic stress, Biomass, Competition, Functional diversity, Plant traits, Trait dissimilarity

Valkó et al. (2013) Basic and Applied Ecology

Orsolya Valkó, Péter Török, Balázs Deák, Béla Tóthmérész (2013): Prospects and limitations of prescribed burning as a management tool in European grasslands. Basic and Applied Ecology, in press. http://dx.doi.org/10.1016/j.baae.2013.11.002


Abstract
Grassland managers and scientists are increasingly interested in cost-effective alternative ways of grassland biodiversity conservation. Prescribed burning is a promising management tool which should be integrated in the planning of management efforts. In addition, small-scale prescribed burning is an effective fire suppression strategy to decrease the serious negative impacts of uncontrolled burnings on ecosystems and human life. Prescribed burning forms an integral part of the North-American grassland management practice, while in Europe it is rarely applied, despite the fact that uncontrolled burning occurs frequently in some regions. Our goal was to evaluate the use of prescribed burning as a promising but neglected management tool in European grasslands. We found that European studies on prescribed burning of grasslands are scarce and we conclude that annual burning is usually not an appropriate option for the conservation of species-rich grasslands. We reviewed burning studies from North-America to identify findings which might be adapted to the European grassland conservation strategy. In North-America, contrary to Europe, the application of burning is fine tuned in terms of frequency and timing, and usually combined with other restoration measures (grazing or seed sowing). Thus, we conclude that with the application of carefully designed prescribed burning, multiple conservation goals, e.g. invasion control and enhancing landscape-level heterogeneity, can be linked with an effective fire suppression strategy. We emphasize that for the application of prescribed burning in Europe, the general findings of carefully designed case studies should be combined with the practical knowledge of conservation managers concerning the local application circumstances to reach specific management objectives.


Keywords
Biomass, Ecosystem services, Fire, Grazing, Mowing, Prairie

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