Large-scale grassland renaturation: Use of so-called establishment windows and highly diverse seed mixtures through knowledge transfer and the provision of regional seed mixtures in Hungary

The collaboration between Hungarian and German partners aims to develop an innovative concept for the cost-effective establishment of species-rich grassland. Very large areas are particularly suitable for two-phase greening, in which the first step involves sowing a species-poor seed mixture that (i) suppresses arable weeds from the soil seed bank and (ii) reduces erosion processes. In the second step, species-rich seed mixtures of regional wild plant species can be sown in so-called establishment windows, which then serve as centers of dispersal. There are gaps in research regarding the size of the establishment windows and the effect of grazing on the establishment and dispersal of the sown target species.

Project priorities

A 760-hectare area of farmland in Hortobágy National Park serves as a model area. Between 2005 and 2008, this area was seeded with two to three regional wild grasses (target vegetation: Festucion pseudovinae Soo 1933, Festucion rupicolae Pop 1968). Due to a lack of seed sources in the area, only a few herbaceous target species have been able to colonize this area so far. This offers a unique opportunity to test the two-phase renaturation approach on a large area. After the test phase, the concept will be implemented at the landscape level and used in the renaturation of other areas in the national park. In general, this method can also be applied to other vegetation types with edaphic or climatic drought stress inside and outside Hungary.

As no regionally produced wild plant seeds are currently available in Hungary, the project is supporting the Salvia Environmental and Nature Protection Association in setting up agricultural propagation for selected target species so that sufficient seeds are available for future renaturation projects. In addition, a database is being set up to record existing species-rich loess and alkaline grasslands in the national park. This should facilitate the search for suitable donor areas for basic seeds and ensure that these areas remain in good conservation condition.

Project region

Hungary

Further project details

• Work package 1: Establishment of regional propagation of native wild plants

  The agricultural production of wild plant seeds is a difficult undertaking. Plants have specific requirements in terms of germination, growth, seed ripening, harvesting, cleaning, and storage. Unfavorable weather conditions, pests, and diseases often push wild seed producers to their limits. While seeds from almost 450 wild plants are now traded in Germany, no regionally produced wild plant seeds are available in Hungary.

  With the support of a German seed producer, target species suitable for agricultural propagation were selected for the renaturation of loess and alkaline grasslands, and their specific requirements were compiled. During a project workshop in Bernburg in May 2014, the Hungarian partners had the opportunity to learn about all the processes involved in the agricultural propagation of wild plants and to meet and discuss with members of the Association of German Wild Seed and Wild Plant Producers during their annual meeting.

  Starting in September 2013, basic seeds of selected species were collected in Hortobágy National Park and sown in a greenhouse in spring 2014. With the support of the national park administration, the Salvia Environmental and Nature Protection Association selected suitable areas for seed production. From September to mid-October 2014, 10 selected species were planted or sown on a 50 m x 50 m field:

  • Achillea collina (30 individuals + seeding)
  • Agropyron pectinatum (only seeding)
  • Centaurea sadleriana (200 indiviuals+ seeding)
  • Dianthus pontedere (300 individuals + seeding)
  • Festuca pseudovina (only seeding)
  • Filipendula vulgaris (600 individuals + seeding)
  • Hypericum perforatum (50 individuals + seeding)
  • Melandrium viscosum (70 individuals + seeding)
  • Phlomis tuberosa (210 individuals + seeding)
  • Salvia austriaca (290 individuals + seeding)
  • Salvia nemorosa (300 individuals + seeding)
  • Silene vulgaris (30 individuals + seeding)

  In order to motivate farmers in the project area to participate in the production of regional wild plant seeds, an information brochure on the basics of wild plant seed production will be produced in English and Hungarian. The aim is also to raise awareness that, in order to protect regional biodiversity, wild plant seeds must be produced in the region where they are used. At the end of the project, a regional workshop will be organized by the University of Debrecen.

  

  

  

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• Work package 2: Donor area register

  In the model area of Hortobágy National Park, the area of species-rich loess and alkaline grassland is steadily declining. Most species-rich loess areas are maintained by the national park administration.

  In order to be able to use the species potential of these old stands for renaturation, it is very important to establish a donor area register. Existing and newly collected vegetation and economic data should be recorded in a database of potential donor areas. This will ensure that the areas remain in good condition and, in consultation with the national park administration, can be used as donor areas for regional seeds.

• Work package 3: Renaturation of species-rich grassland

  In October 2013, a total of 32 establishment windows were created in the Hortobágy National Park at four alkaline and four loess sites: 16 x 16 m² (8 fenced, 8 unfenced), 8 x 2 m², 8 x 1 m²; the distances between the sites are at least 50 m. After tilling and seedbed preparation, the areas were sown with a seed mixture of 35 regionally collected herbaceous species at a rate of 10 g/m². The selected target species are characteristic of Festucion pseudovinae Soo 1933 and Festucion rupicolae Pop 1968 communities. Since the entire area is covered with loess loam and the differences in salinity are only present in the subsoil, only one mixture was used. Due to the different salt tolerance of the selected species, the gradually effective capillary rise of saline water will lead to different, mosaic-like patterns in the long term.

  The following questions are at the forefront:

  1. does disturbance of the turf have a positive effect on the establishment of target species?
  2. At what minimum area size can the target species that have been sown be successfully established and propagated?
  3. How does the management regime (with/without grazing) influence the establishment rate and seed production of the seeded species?

  In order to investigate the factors that are decisive for the successful colonisation of unseeded control areas, comparative studies on the spread behaviour of introduced target species were carried out on old renaturation trials in Germany and Hungary. To this end, the number and coverage of immigrated target species were documented in the summer of 2014 on 5 m x 5 m permanent plots without seeding.

• First results

  Establishment window

  In the first year, 33 of the 35 species sown were able to establish themselves in all establishment windows in Hortobágy National Park. Separated by variant, the following establishment rates occurred: 1 m² 66%, 4 m² 86%, 16 m² (unfenced) 89%, 16 m² (fenced) 80%.

  Compared to the 1 m² and 4 m² areas, the seeded species on both 16 m² establishment plots achieved the highest values for average number and average coverage. The number of species on the fenced variants tended to be lower than on the unfenced variants. In terms of coverage, however, the highest values were observed on the fenced areas for the seeded species and the lowest values for the spontaneous species.

  

  

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  Immigration of target species

  Nine years ago, potential alkali and loess sites in Hortobágy National Park were seeded with two and three regional grasses, respectively. By 2014, lower salt content on loess sites had allowed more target species to establish themselves on average than on alkali sites. The seeded grasses continue to dominate at both sites.

  Three sites were studied in Germany: (1) Grassaum Strenzfeld, (2) seeded embankment (3 cultivated grasses) at the Profen open-cast mine, (3) embankment greened by spontaneous succession at the Roßbach open-cast mine. Here, the number of target species that have migrated to the site shows a clear correlation with the age of the area and the grass cover.

  

  

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