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Földalatti ökoszisztéma-mérnök fajok szerepe a gyepek fenntartásában
49-55Views:90In this review we would like to analyze the effects of the subterranean rodents on vegetation using results from research of several taxons in different vegetation types and climate. Ecosystem engineers are organisms that modify, maintain, and create habitats. Subterranean rodents belong to this group. These species have an impact on the vegetation the microtopographical features of the soil and bulk density, they can change the structure, organic matter and moisture content of the soil they reduce the proportion of nitrogen. The fossorial rodents occur almost all over the world (expect Australia and Antarctica). These herbivorous species burrow tunnels under the ground and with this they have an impact on the floral diversity and dominance relations, the structure and composition of the association, the amount of biomass production as well as the distribution of plants and seeds. They can take effect directly with consumption of plants and indirectly with affect the plant-soil relations. At the basis of the results the activity of the subterranean rodents enhanced the diversity in most of the cases (of course there were also negative results and some researcher didn't find any differences between the mounds and the plots with no mounds). Their effect on the biomass was usually negative but they changed the species composition of their habitat at all times.
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Kaszálás felhagyás hatása helyreállított szikes és löszgyepek vegetációjára
21-29Views:68Grasslands recovered by sowing of low diversity seed mixtures are frequently managed by mowing. However only a few studies focused on the direct effects of post-restoration mowing on recovered grassland vegetation. In this study we followed vegetation changes in 13 recovered grasslands, in 5×5-m-sized exclosures with continuous and ceased mowing in Hortobágy, East-Hungary. We asked the following study questions:
(i) What are the effects of cessation of mowing on the vegetation structure of recovered grasslands?
(ii) What are the effects of cessation of mowing on the abundance of sown grasses, target and weed species?
(iii) Is yearly mowing an appropriate management for the maintenance of recovered grasslands?
Our results showed that the cessation of mowing caused litter accumulation, decrease in total cover and decrease in the cover of sown grasses compared to the continuously mown exclosures. The cover of perennial weeds was significantly higher in unmown exclosures compared to the mown ones. The species composition in mown exclosures remained more similar to reference grasslands than to the unmown ones. Our results suggest that without a regular post-restoration mowing the favourable stage of recovered grasslands can be rapidly vanished caused by litter accumulation and/or by the expansion of undesirable weedy species. We also stress that yearly mowing is solely enough to maintain grasslands recovered by low-diversity seed sowing, but cannot be considered to be enough to recover target vegetation composition.
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The vegetation of the pastures from the Aninei mountains
23-25Views:45The situation of the Aninei Mountains in the South-Western part of Romania, at the interference of air masses with maritime (of Western origin), continental (of Eastern origin) and Southern character (coming across the Mediterranean Sea), as well as the carstic relief conferred by the calcareous geologic substrate, account for the floristic peculiarities of this region, containing numerous rare and characteristic Banatian elements. The European, Southern and Eastern influences are expressed in the diversified floristic composition of the pastures, where xerophile and xeromezophile species prevail. A pecularity of the researched area is represented by the calcophile vegetation of the xerophilic pastures. In the floristic composition, we were able to identify several sporadic species in Romania.
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Degradation degree evolution under different grassland management
35-44Views:96The objective of this manuscript is to clarify the changes in vegetation structure of an extensively managed grassland association under different land use practices. In the grasslands of the Hungarian Great Plain, the westernmost part of the Eurasian steppe, the largely decreasing grazing livestock numbers and the almost disappearing pastoral grazing make the topic very topical. We analysed the last 4 years of the study period 2009-2020 and found that the lowest degradation rates were measured in the meadow utilisation management, with values ranging from 0.277-0.463 in the 11th year of the experiment. And the highest degradation values were measured in the treatment with the overgrazing mode, with degradation degrees 3.43-5.0 in the 11th year of the experiment. In the treatment demonstrating the effect of overgrazing, we measured a high increase in the cover value of the weed Hordenum murinum, which is very dangerous for sheep, between 2017 and 2020, with an average of 107.6%.
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Possibilities of restoration of natural or seminatural grasslands: Papers of the „Challenges and Aspects in Grassland Management” conference held on 22-23 May 2008.
19-27Views:82The number of natural grassland restoration projects increased in the last decade in Hungary, and probably the area of restored grasslands will be significantly extended in the next years due to New National Rural Development Program. To contribute to the success of this activity, in this paper we review the most important theoretical and practical aspects of natural grassland restoration methods. In the course of grassland restoration, habitats dominated by grasses and/or sedges have been restored in place of arable lands. In order to perform “natural” restoration, we should consider the ecological conditions of the landscape, and reconstruct natural or seminatural grasslands including of native plant species. Essentially, rehabilitation of natural landscape is supported also by creating new seminatural grassland patches. The basic principles of the natural grassland restoration are:
1. When a spontaneous secondary succession starts to proceed on an abandoned field without invasion of any alien plant species, the re-ploughing of the abandoned field has to be ignored.
2. Generally, the old fields surrounded by species-rich natural or seminatural grassland pathes can succesfully be restorated. Then, as a consequence of newly restored vegetation patches the recovery of the whole landscape can be accelerated. Furthermore, by restoring isolated grassland patches surrounded by arable lands a more diverse landscape pattern could be developed.
3. Spontaneous secondary succession of grasslands should be assisted.
4. The development of typical species composition of a seminatural grassland can be promoted by methods of spreaded hay. For successful process the hay has to be cut in a habitat type similar to ones that will be restored.
5. Applying seed-mix for sowing can be useful to prevent spreading weeds drastically in the early stages of succession.
6. Ideally, the seed-mix is originated from own harvesting or gathering from similar (or the same) habitats. If it is not possible, commercially available seed-mix can be applied, in which the dominant species is the same as in the restored habitat, with similar proportion.
7. Seed-mix consists of alien species has to be avoided.
8. If the composition or structure of the restored grassland is not appropriate after some years, the renewal of the grassland could be necessary. During the improvement process the reploughing of the restored grassland is avoided, but spreading seeds or hay, and direct sowing can be applied.
9. The loading of nutrient is not necessary in any stages of grassland restoration.
10. Applying chemicals is avoided; any herbicides can be used only when extensive invasion of alien plant species occurs.
11. The mechanical intrusions on soil are also avoided.
12. The restored grasslands is required regular or continuous management, which could be a preserving mowing or moderate grazing. The aspects of nature conservation should be considered.
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Relationship between the diversity and mowing in cleared grassland areas in the Börzsöny mountains
3-13Views:67Nowadays, mowing has an increasing role in the management of semi-natural and nature conservation areas. Semi-dry grasslands have been formed on cleared areas of forest in the Pannon mountains, which would be reclaimed by forest without use of the areas by humans. In our work we analysed cleared grasslands. The questions we aimed to answer were the following:
(i) What kind of vegetation changes were caused by different land use types?
(ii) Is mowing a proper method for grassland management and nature protection in the studied system?
(iii) Do the species composition and the diversity vary within two years when conditions of precipitation are different?
In four sampling areas situted in Börzsöny mountains (North-Hungary), we registered the plant species and their cover values in ten quadrats per sampling area. We performed a site assessment in April, June and October, 2013-2014. We analysed the data by using cluster and ordination processes and we compared the sampling areas on the basis of the humidity preference and Shannon’s index of diversity. From nature conservation’s point of view, it is favourable that the cover of Potentilla alba occurring in the area was high. It is a specialist plant species with low stress resistance. However, due to tourism, it occured less frequently in the area and Bromus erectus became dominant instead. The species whose cover was more extensive in areas not affected by tourism – for example Alopecurus pratensis, Galium verum, Carex praecox, Trisetum flavescens – occurred less frequently in areas affected by tourism. On the short run, species did not completely disappear due to the changing conditions but their abundance decreased, as has been already supported by other surveys. The ordination analysis showed that the composition of species considerably differed with the portions of land cultivated in different ways. The change of the cover values was apparent not only in the case of the dominant species but of also in case of species with smaller cover. The decrease of diversity, the change of plant cover, the decrease of number of sensitive species as a result of tourism are typical phenomena all over the world. The Shannon’s diversity records showed that due to human presence and trampling the diversity declined. It was considerably lower in the year with less rain. In the year with more rain the diversity of species was considerably higher, however, the difference in between the surveyed areas was large. All these examples draw attention to the important role of environmental factors alongside the human factors. The water reserve also influences the productivity of grasslands and water has primary importance in the structure of plant communities. According to the survey, in the two areas not affected by tourism, in the rainier year the difference between the humidity preference of the species of the dry and the less dry patches became similar. On these areas, there were more species with higher humidity preferences in the rainier year, however, this tendency could not be observed in the rainier year on areas affected by tourism. The areas affected by tourism may react in a less flexible manner to the change in precipitation conditions. Based on our analysis, we can conclude that the surveyed semi-dry grasslands are extremely rich in species and therefore proper grassland management plans are needed. To preserve grasslands of high natural value, the impacts of the environmental factors should also be considered in addition to becoming acquainted with the history and the present conditions of landscape use.
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The Role of Grassland in EU Soil Protection Strategy
3-15Views:63The three most important life quality criteria are: healthy and good-quality food, clean water and pleasant environment. All three are closely related to the sustainable management of natural resources; conservation of soil and water resources; rational land use and landscape preservation. Soils are conditionally renewable natural resources, consequently, their rational use, conservation, and the maintenance of their multipurpose functionality have particular significance both in the national economy and environment protection. The main soil functions are: integrator (transformer) of other natural resources; most important media for biomass production; storage of heat, water, nutrients, pollutants; buffer of various natural and human-induced stresses; huge natural filter (preventing groundwater pollution); detoxication media of various harmful substances; habitat for soil biota, gene-reservoir, media of biodiversity; conservator of the natural and human heritage.
The maintenance of these functions is the key-element of sustainable development on all levels of the decision-making process: Globe → continent → region → country → subregion → settlement → farm → field. The EU Strategy for soil protection focuses attention on 8 environmental threats, for their prevention, elimination or moderation:
– water and wind erosion;
– decrease in organic matter resources;
– compaction and structure destruction;
– soil sealing;
– the increasing frequency, duration and degree of extreme moisture events: flood, waterlogging – drought;
– point and non-point (diffuse) soil pollution;
– salinization/alkalization/sodification;
– decline in biodiversity (decreasing number and activity of soil organisms, narrowing their species spectra).
The EU-conform Soil Conservation Strategy of Hungary was elaborated during the last decades on the basis of long-term soil survey, soil analyses, soil mapping and soil monitoring activities. It comprises three main tasks:
– the prevention, elimination or moderation of soil degradation processes;
– the reduction of the unfavourable economic, ecological, environmental and social consequences of extreme moisture regimes;
– the control of the biogeochemical cycle of elements: optimum nutrient supply of plants; prevention of harmful soil pollution and contamination of the „food chain”.
Grassland management has to play a significant role in these actions. In addition to fodder production, rational grassland management can considerably contribute to the storage, buffer, filter and gene-reservoir functions of soil, to the improvement of soil moisture regime, to the moderation of extreme moisture conditions, and to the reduction of soil losses caused by water or wind erosion. In spite of these favourable impacts grasslands (covering about 12% of Hungary) have never been in the focus of Hungarian agriculture.
Grasslands were always restricted to marginal lands (sands, salt affected soils, peatlands, floddplains) with low and risky (highly weather-dependent) biomass production and low animal carrying capacity. Relatively productive grasslands were upturned for corn in large hilly areas (resulting serious erosion losses and landscape deterioration); the huge floodplain grasslands were used for other agricultural crops after flood control and river regulation; peatland grasslands were also considerably reduced by the drainage of these areas and used (not always successfully and efficiently) for arable crops. Huge areas became seriously degraded wastelands or „weedlnds” due to irregular grazing, lack of weed control, plant nutrition, water management. Under improper management not only the biomass production decreased considerably but the soil conservation functions of grassland were also deteriorated, sometimes dramatically. The poor and degraded grassland vegetation were not able to prevent (or at least moderate) water erosion losses in hilly areas, wind erosion losses in the dry sand regions or „over-drained” ameliorated peatlands, and even their gene-reservoir functions are sometimes threatened seriously.
Rational grassland management is an important element of both the European and Hungarian Soil Conservation Strategy. Its scientific bases are well-known. The details have to be determined by further research and scientific programs. The existing knowledge should be broadcast using all available information channels: teaching and education on various levels; demonstrations; media programs, etc. A proper system of stimulating economy regulations should be developed and formulated in various-level legal documents. But first of all an environment-friendly moral must be developed accepting the concept of sustainable grassland management.