Tamás Miglécz

Litter and graminoid biomass accumulation suppresses weedy forbs in grassland restoration

Abstract Accumulated biomass of sown species and litter plays an important role in success of restoration projects. We studied the effects of litter and graminoid biomass on species richness and biomass of early colonising forbs in former alfalfa fields sown with seed mixtures containing seeds of native grass species (Festuca pseudovina, Festuca rupicola, Poa angustifolia, Bromus inermis, 2005). The amount of litter, forbs and graminoids was measured in the first 3 years after sowing (2006–2008). Ten aboveground biomass samples (20 cm × 20 cm) per field were collected in June every year. We found significantly lower forb biomass in the second and third year, than in the first year after sowing. Litter and biomass of graminoids increased significantly during the study, and correlated negatively with the biomass and species richness of forbs. Mean scores of litter and graminoid biomass were two to three times higher in sown fields than in native grasslands. Our results suggest that the accumulation of litter and graminoid biomass is beneficial in suppression of weedy forbs, but in the long run it might also hamper the immigration of target species.

Rainfall fluctuations and vegetation patterns in alkali grasslands - using self-organizing maps to visualise vegetation dynamics

Knowledge about the drivers of vegetation dynamics in grasslands is fundamental to select appro-priate management for conservation purposes. In this study, we provide a detailed analysis of vegeta-tion dynamics in alkali grasslands, a priority habitat of the Natura 2000 network. We studied vegetation dynamics in five stands of four alkali grassland types in the Hortobagy National Park (eastern Hunga-ry), between 2009 and 2011. We analysed the effect of fluctuations in precipitation on both the overall vegetation composition and on the cover of each species using Self Organizing Map neural networks (SOM). We found that SOM is a promising tool to reveal plant community dynamics. As we analysed species cover and overall vegetation composition separately, we were able to identify the species re-sponsible for particular vegetation changes. Fluctuations in precipitation (a dry season, followed by a wet and an average season) caused quick shifts in plant species composition because of an increasing cover of halophyte forbs, probably because of salinisation. We observed a similar effect of stress from waterlogging in all studied grassland types. The species composition of Puccinellia grasslands was the most stable over the three years with varying precipitation. This was important as this grassland type contained many threatened halophyte species. Self-organising maps revealed small-scale vegetation changes and provided a detailed visualisation of short-term vegetation dynamics, thus we suggest that the application of this method is also promising to reveal community dynamics in more species-rich habitat types or landscapes.

Abandonment of croplands: problem or chance for grassland restoration? case studies from hungary

Abstract In Central‐ and Eastern Europe, the collapse of socialist regimes resulted in a transformation of state‐owned agricultural cooperatives to privately owned lands from the early 1990s onwards. These socioeconomic processes resulted in landscape‐scale changes in biodiversity, ecosystem services and agricultural production. In parallel, large‐scale abandonment of croplands, especially on sandy, salty or frequently inundated areas, became common. Abandoned croplands are usually sensitive to species invasions, and are hotspots of noxious weeds, posing threats both to agriculture and nature conservation. Grassland restoration on former croplands can be an effective strategy for suppressing these species. Thus, a common goal of nature conservation and agriculture can be the restoration of grasslands on former croplands to (1) suppress weed and/or invasive species in line with the policy “Good Farming Practices”, (2) support animal husbandry by creating meadows or pastures, and to (3) recover biodiversity and ecosystem services. In the present paper we report “best practices” of grassland restoration projects from Hungary. Our aim was to compare the effectiveness of spontaneous grassland recovery vs. active grassland restoration by seed sowing in terms of the recovery of biodiversity and ecosystem services, such as weed control and biomass production. Our results showed that grassland restoration on abandoned fields offers a viable solution for restoring biodiversity and ecosystem services. Seed sowing ensures higher weed control and biomass production, but results in lower biodiversity compared to spontaneous recovery. Both restoration methods can be cost‐effective, or even profitable even within a relatively short period of a nature conservation project.

New measurements of thousand-seed weights of species in the Pannonian flora

For understanding local and regional seed dispersal and plant establishment processes and for considering the ecotypes and other forms of specific variability, hard data of locally or regionally measured traits are necessary. We provided newly measured seed weight data of 193 taxa, out of which 24 taxa had not been represented in the SID, LEDA or BiolFlor databases. Our new measurements and formerly published data of locally collected seed weight records together covers over 70% of the Pannonian flora. However, there is still a considerable lack in seed weight data of taxonomically problematic genera, even though they are represented in the Pannonian flora with a relatively high number of species and/or subspecies (e.g. Sorbus, Rosa, Rubus, Crataegus and Hieracium). Our regional database contains very sporadic data on aquatic plants (including also numerous invasive species reported from Hungary and neighbouring countries) and some rare weeds distributed in the southwestern part of the country. These fact...

Early vegetation development after grassland restoration by sowing low-diversity seed mixtures in former sunflower and cereal fields

We studied the early vegetation dynamics in former croplands (sunflower and cereal fields) sown with a low-diversity seed mixture (composed of 2 native grass species) in Egyek-Pusztakócs, Hortobágy National Park, East-Hungary. The percentage cover of vascular plants was recorded in 4 permanent plots per field on 7 restored fields between 2006 and 2009. Ten aboveground biomass samples per field were also collected in June in each year. We addressed two questions: (i) How do seed sowing and annual mowing affect the species richness, biomass and cover of weeds? (ii) How fast does the cover of sown grasses develop after seed sowing? Weedy species were characteristic in the first year after sowing. In the second and third year their cover and species richness decreased. From the second year onwards the cover of perennial grasses increased. Spontaneously immigrating species characteristic to the reference grasslands were also detected with low cover scores. Short-lived weeds were suppressed as their cover and biomass significantly decreased during the study. The amount of litter and sown grass biomass increased progressively. However, perennial weed cover, especially the cover of Cirsium arvense increased substantially. Our results suggest that grassland vegetation can be recovered by sowing low diversity mixtures followed up by yearly mowing. Suppression of perennial weed cover needs more frequent mowing (multiple times a year) or grazing.

New aspects of grassland recovery in old-fields revealed by trait-based analyses of perennial-crop-mediated succession

Abstract Classical old‐field succession studies focused on vegetation changes after the abandonment of annual croplands or on succession after the elimination of cultivated crops. Perennial‐crop‐mediated succession, where fields are initially covered by perennial crops, reveals alternative aspects of old‐field succession theories. We tested the validity of classical theories of old‐field succession for perennial‐crop‐mediated succession. We formulated the following hypotheses: (1) functional diversity increases with increasing field age; (2) resource acquisition versus conservation trade‐off shifts toward conservation at community level during the succession; (3) the importance of spatial and temporal seed dispersal decreases during the succession; and (4) competitiveness and stress‐tolerance increases and ruderality decreases at community level during the succession. We studied functional diversity, trait distributions and plant strategies in differently aged old‐fields using chronosequence method. We found increasing functional richness and functional divergence, but also unchanged or decreasing functional evenness. We detected a shift from resource acquisition to resource conservation strategy of communities during the succession. The role of spatial and temporal seed dispersal was found to be important not only at the initial but also at latter successional stages. We found an increasing stress‐tolerance and a decreasing ruderality during succession, while the competitiveness remained unchanged at the community level. Despite the markedly different starting conditions, we found that classical and perennial‐crop‐mediated old‐field successions have some similarities regarding the changes of functional diversity, resource acquisition versus conservation trade‐off, and seed dispersal strategies. However, we revealed also the subsequent differences. The competitive character of communities remained stable during the succession; hence, the initial stages of perennial‐crop‐mediated succession can be similar to the middle stages of classical old‐field succession. Moreover, the occupied functional niche space and differentiation were larger in the older stages, but resources were not effectively utilized within this space, suggesting that the stabilization of the vegetation requires more time.

Litter removal does not compensate detrimental fire effects on biodiversity in regularly burned semi-natural grasslands

Regulation of plant biomass accumulation is a key issue in effective grassland conservation in Europe. Burning is an alternative tool to regulate biomass dynamics in semi-natural grasslands even in the absence of grazing or mowing. We tested the effects of regular spring burning on the biomass fractions and fine-scale plant species composition of species-rich foothill grasslands in North-Hungary. There were five regularly burned and five control grasslands in the study; we collected twenty 20×20-cm sized biomass samples from each. We analyzed the main fractions (litter, graminoid and forb biomass), and the species-level biomass scores, and flowering success in the control and burned grasslands. We revealed that fire increased the amount of forb biomass and decreased the amount of litter, which suggested that regular burning might be feasible for regulating biomass dynamics. The non-metric multi-dimensional scaling (NMDS) showed a high similarity of the control and burned grasslands in species composition. However, plant diversity, and the number of flowering shoots decreased significantly in the burned grasslands. In regularly burned sites we found a significant decline of specialist species, as well as of steppic flora elements. Our results showed that besides its positive effect on biomass dynamics, high-frequency burning threatens the overall diversity and specialist plant species in semi-natural grasslands. We recommend that proper fire regimes should be first studied experimentally, to provide a scientific basis for the application of prescribed burning management in such habitats.

Germination capacity of 75 herbaceous species of the pannonian flora and implications for restoration

Seeds ensure the survival and dispersal of the majority of vascular plant species. Seeds require species-specific germination conditions and display very different germination capacities using different germination methods. Despite the importance of plant generative reproduction, little is known about the germination capacity of the seeds of the Pannonian flora, particularly under field conditions. Our aim was to reduce this knowledge gap by providing original data on the germination capacity of 75 herbaceous species. We reported the germination capacity of 8 species for the first time. We also highlighted the year-to-year differences in the germination capacity of 11 species which could be highly variable between years. The data regarding the germination capacity of target species, as well as weeds and invasive species, can be informative for nature conservation and restoration projects. Our findings support the composition of proper seed mixtures for ecological restoration and also highlight the importance of testing seed germination capacity before sowing.

Comparison of species-rich cover crop mixtures in the Tokaj wine region (Hungary)

Intensive agricultural practices of past decades—such as mechanical cultivation on steep vineyard slopes—can endanger soil fertility. In addition, climate change scenarios predict heavier rainstorms, which can further accelerate soil degradation. Therefore, the use of cover crops in the inter-row has a special importance, particularly on steep slopes and in organic agriculture. A species-rich cover crop mixture helps not only in preventing erosion and providing easier cultivation, but has also positive effects on soil structure, soil fertility and ecosystem functions (Bauer et al. 2004; Hofmann et al. 2008). We began to develop and test several species-rich cover crop mixtures in spring of 2012 in Hungarian vine regions. During the experiments, three species-rich cover crop mixtures (Biocont-Ecovin mixture, mixture of legumes, mixture of grasses and herbs) were compared in vineyards of the Tokaj vine region. Each mixture was sown in three subsequent inter-rows at each site of the experiment. In the control blocks, unsown inter-rows and mechanically cultivated inter-rows were located subsequently next to each other. We studied weed control, yield quantity and must quality in every treatment. We found that the cover of weeds was lower in every treatment compared to the unsown control plots for 2013; thus, cover crops suppressed the weeds of the inter-rows effectively. Most examined indices of grapevines were not significantly affected by the applied cover crops. However, the yield loss results show that under Hungarian climate, the soil coverage in every second inter-row is more recommendable than subsequent seeding, where total erosion control is not required. The interest of the vine growers shows the importance of the topic; thus, we involved other wine regions of Hungary in our further experiments.