Deák et al. (2015) Basic and Applied Ecology

Balázs Deák, Orsolya Valkó, Péter Török, András Kelemen, Tamás Miglécz, Szilárd Szabó, Gergely Szabó, Béla Tóthmérész (2015): Micro-topographic heterogeneity increases plant diversity in old stages of restored grasslands. Basic and Applied Ecology, in press. doi:10.1016/j.baae.2015.02.008

Abstract

It is a truism in ecology that environmental heterogeneity increases diversity. Supporting field studies are mostly concerned with a large-scale topographic heterogeneity, ranging from a couple of meters to landscape-scale gradients. To test the role of fine-scale micro-topography on plant diversity, we studied the initial vegetation of recently filled (1-year-old), and established vegetation on old (7-year-old) soil-filled channels in an alkali landscape, East-Hungary. We hypothesised that (i) recently filled channels are characterised by a high cover of ruderal species and high species diversity and (ii) high micro-topographic heterogeneity increases the diversity of species and plant strategy types (mixed C-S-R categories) in early stages but later on this effect diminishes. We found that diversity of species and plant strategy types was higher in recently filled channels compared to old filled channels. Micro-topographic heterogeneity had no effect on the studied vegetation parameters in recently filled channels. Conversely, in old filled channels higher micro-topographic heterogeneity resulted in higher diversity and lower cover of the dominant grass Festuca pseudovina. Higher micro-topographic heterogeneity resulted in increased ruderality and decreased stress-tolerance, but it did not increase the diversity of plant strategy types. In contrast with former studies, we found that a couple of centimeters of micro-topographic heterogeneity had no effect on vegetation in recently filled channels, but supported a high diversity in old filled channels. An important practical implication of our study is that in grassland restoration projects, micro-topographic heterogeneity has a crucial role in sustaining biodiversity.

Keywords

Alkali landscape, C-S-R strategies, Elevation, Functional diversity, Grassland restoration, Plant trait, Soil disturbance, Succession, Topography

Kelemen et al. (2014) Biodiversity and Conservation

András Kelemen, Péter Török, Orsolya Valkó, Balázs Deák, Tamás Miglécz, Katalin Tóth, Tamás Ölvedi & Béla Tóthmérész (2014): Sustaining recovered grasslands is not likely without proper management: vegetation changes after cessation of mowing. Biodiversity and Conservation, in press. DOI: 10.1007/s10531-014-0631-8


Abstract
Grasslands recovered by sowing low diversity seed mixtures of local provenance are usually managed by mowing. Besides restoration success only a few studies have focused on the direct effects of post-restoration mowing on recovered grassland vegetation. In this study we followed vegetation changes in 13 successfully recovered grasslands in 5 × 5-m-sized sites with continuous and ceased mowing at Hortobágy National Park, East-Hungary. We asked the following questions: (i) What are the effects of cessation of mowing on the vegetation structure and diversity of recovered grasslands? (ii) What are the effects of cessation of mowing on the abundance of sown grasses, target and undesirable species? (iii) Is yearly mowing an appropriate management tool for the maintenance of recovered grasslands? Our results showed that the cessation of mowing caused litter accumulation, while diversity, total vegetation cover and the cover of sown grasses decreased compared to the mown sites. The cover of undesirable perennial species was significantly higher in unmown sites than in mown ones. The species composition of mown sites remained more similar to near-natural grasslands than the unmown ones. Our results suggest that without regular post-restoration mowing the favourable status of recovered grasslands can rapidly decline due to litter accumulation and by the expansion of undesirable species, even in the short-run. We also stress that while yearly mowing is enough to maintain grasslands recovered by low-diversity seed sowing, it cannot be considered to be enough to recover target vegetation composition.


Keywords
Grassland restoration, Seed sowing, Abandonment, Post-restoration management, Biodiversity, Cirsium arvense

Albert et al. (2014) Applied Vegetation Science

Ágnes-Júlia Albert, András Kelemen, Orsolya Valkó, Tamás Miglécz, Anikó Csecserits, Tamás Rédei, Balázs Deák, Béla Tóthmérész & Péter Török (2014): Secondary succession in sandy old-fields: a promising example of spontaneous grassland recovery. Applied Vegetation Science, DOI: 10.1111/avsc.12068, PDF itt

Abstract
Question: Based on the spontaneous vegetation development of old-fields in the Nyírség and Kiskunság sand regions (Hungary), we aimed to answer the following questions using the chronosequencemethod: (1) how do the proportions of different functional groups change during succession; (2) which target species establish successfully in the old-fields during the course of succession; and (3) how successful is spontaneous succession in the recovery of target grasslands?
Location: Two sand regions of the Great Hungarian Plain: (1) the Nyírség sand region (East Hungary, acidic sand, moderately continental climate) and the Kiskunság (Central Hungary, calcareous sand, continental climate).
Methods: Altogether 24 old-fieldswere classified into young (<10-yr-old),middle-aged (10–20-yr-old) and late-succession (20–40-yr-old) old-fields; four fields in each age category. For baseline vegetation reference, three open and three closed sand grassland stands in both regions were sampled in the vicinity of the old-fields. The percentage cover of vascular plants was recorded in five 2 9 2-m plots in each field, in early May and late June 2012. We used life forms, clonal spreading traits and Ellenberg indicator values for nutrients in the analysis. Species of Festuco-Brometea class were considered as target species.
Results: The cover of hemicryptophytes and geophytes increased, the cover of short-lived species decreased with time. Cover of species without clonal spreading ability decreased, while cover of species with clonal spreading ability increased with increasing field age. The cover of invasive species decreased with increasing field age. The majority of target species had established already in the young and middle-aged old-fields, although their cover was significantly higher in the two older age groups.
Conclusion: Spontaneous succession can be a vital option in recovery of sand grassland vegetation in Central Europe; the majority of the species pool of sandy grasslands can be recovered in the first 10–20 yrs. However, the success of grassland recovery can be strongly influenced by the surrounding species pool and can be slowif seed dispersal is limited. Spontaneous succession ismost promising when the target species of grasslands immigrate at the very beginning of the succession, within the first few years.


Keywords
abandonment, acidic sand, calcareous sand, clonal traits, grassland restoration, invasion, spontaneous succession

Valkó et al. (2012) Flora

Orsolya Valkó, Péter Török, Gábor Matus, Béla Tóthmérész (2012): Is regular mowing the most appropriate and cost-effective management maintaining diversity and biomass of target forbs in mountain hay meadows? Flora 207(4): 303-309.


Abstract
Conservation of grassland biodiversity is a key issue in the EU agro-biodiversity policy. We assessed the effects of yearly mowing on target forb biomass in years with contrasting precipitation (2006–2007) in mountain fen and dry-mesophilous hay meadows in NE-Hungary. We hypothesised: (i) Species richness and biomass of target forbs is higher in mown than in abandoned stands. (ii) Mowing has more an effect on the biomass of target forbs, graminoids and litter than precipitation.

Mowing increased the species richness of forbs and target forbs. The biomass of forbs and target forbs was not affected by mowing because of the specific responses of certain forbs. The majority of target species were supported, but tall forbs (Succisa pratensis; Lathyrus pratensis) were suppressed by mowing. Precipitation affected only the amount of litter in dry-mesophilous meadows and forb biomass in fen meadows. In the dry year, the biomass of target forbs decreased but the proportion of the species did not change. Our results showed that mowing is necessary to maintain overall plant biodiversity in hay meadows by removal of graminoid biomass and litter, but not all target forbs were favoured by regular yearly mowing. Decreased mowing frequency (mowing in every second or third year) on the entire meadow or temporarily changing mosaics of mown and unmown stripes might be the most suitable management option for maintaining the highest biodiversity of forbs.

Keywords
Target species; Phytomass; Grassland biodiversity; Mosaic management; Cost-effectiveness; Grassland restoration

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