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Regional habitat pattern of the Danube-Tisza Interfluve in Hungary, I
The landscape structure and habitat pattern; the fen and alkali vegetation
As a result of the groundwater level decline observed in the last two decades and the socio-economic changes, we assume that a drastic alteration begins in the landscape pattern of Danube-Tisza Interfluve (Duna-Tisza köze, Kiskunság s. l.). It demands the documentation of the actual state of vegetation in this region, and its quantitative analysis, as well. In the first of the two articles presenting our results we discuss the regional habitat-pattern of the landscape, the background factors determining it, and the basic features of fen and alkali vegetation. In the second part, this will be completed by the sand, riverine and steppe vegetation and the data on habitat-devastation on the regional scale.During our study we determined the Danube-Tisza Interfluve (with a total extension of nearly 1.4 million ha) in the geographical sense. The analysis of the present habitat-pattern of the region was based on data of the actual (1996–2000) habitat map of Danube-Tisza Interfluve (Molnár et al. 2000, Biró et al. 2000) and on our experience during the field survey. We compared our data to surface-geographical, pedological and hydrological works, to maps from the 18–19th centuries on land-use, to botanical studies accomplished in the 19–20th centuries and to the results of other related sciences. The quantitative analysis of the vegetation pattern was carried out considering the vegetation subregions.About half (49.4%) of the surveyed, not cultivated habitats of the Danube-Tisza Interfluve is in a natural, semi-natural state, and nearly a quarter of them (23.8%) is essentially disturbed or under deep human impact. During the one- and-a-half decades between the topographical mapping of the mid-1980s and the habitat mapping (D-TMap), 14.7% of the surveyed habitats disappeared, and appr. 12.1% is now in the state of regeneration after the disturbance of the distant or the recent past. Today, fen vegetation (including the vegetation of non-alkali swamps and uncharacteristic fen vegetation that is drying out at present) is predominant among the studied habitats of the region (it covers 95,135 ha), that is followed by alkali vegetation with an extension of about half of the former one (47,226 ha).The joint vegetation categories (sand, fen, alkali and riverine vegetation) of the region compose vegetation zones running north and south. So, on the two sides of the Sand Ridge vegetation zones dominated by fen habitats lie, which is followed by the zone of alkali habitats; finally, the riverine vegetation prevails along the rivers Danube and Tisza. From the abiotic factors determining these zones we emphasised the hydrodynamic characteristics — that play recently the most essential role. As a result of the analysis of landscape pattern, it became obvious, that the natural habitats — similarly to the hydraulically continuous groundwater flow systems — of the Danube-Tisza Interfluve compose hierarchical systems, basically on three different levels (on the local, intermediate and regional scale). In this point of view, those areas are considered as a certain system, where the underground water flow (recharge, throughflow and discharge) forms a uniform flow system. We approached to the survey of the actual vegetation of the Danube-Tisza Interfluve with this viewpoint of the hierarchically structured habitat pattern.
Due to its nearly 1.5 million ha extension and the aimed fine mapping resolution, classical vegetation mapping was not suitable method to prepare the habitat map of Duna-Tisza köze region (Hungary). We developed a novel mapping method. By this method the actual status of more than 12,000 patches of semi-natural vegetation was recorded, documented previously as grasslands, wetlands, open forests and grasslands with scattered trees and shrubs in the middle of the 1980s. A digital layer of 272,387 ha at 1 : 25,000 resolution was created as the background of the analysis. Vegetation type was classified at 46,930 points in the mapping area. The collaboration of 59 colleagues resulted in the development of the digital geographical database of the study area (D-TMap GIS Point database). One-third of the data relies on field data, while the other two-thirds on satellite interpretation. Landscape pattern and the accuracy of the statistical data of the habitats, generated from the point database, are improved by the polygonised version of the point database (D-TMap GIS Polygon database). In this paper we show how the GIS Point database was generated, and summarise the ecological content, availability, and limitation of the derived point and polygon based actual habitat maps. Analysis of the database and the landscape scale pattern of the habitats are discussed in a further paper.
As conservation of sensitive habitats is a high priority issue in European environmental policy, there is considerable interest in mapping and monitoring specific habitats of high conservation value. In this study, we discuss the potential of the Swiss mire monitoring program to monitor small area habitats in sufficient detail. The monitoring scheme combines nationwide probability sampling and predictive habitat mapping based on a field data sample. Thus, it is designed to identify spatiotemporal changes at the stand level and to derive hard statistics for the sub-national level. For feasibility reasons, the thematic focus is on semi-quantitative mean indicator values derived from vegetation records. These measures provide robust estimates of essential floristic site conditions. Regression models based on CIR aerial photographs are applied to continuously map respective measures across the sample mires. The present study explores the required investment of data for model-based mapping. Exemplary mapping results are presented and validated within a reference mire. Repeated tests show that about one hundred field records are needed to guarantee optimal prediction accuracy and reliable error estimates for all target variables. The corresponding 95% error quantiles in a test data set are below 0.7. To evaluate the benefit of high resolution orthophotos (30 cm resolution), the model prediction is compared with results obtained from coarsened images. Although the original CIR images produce the best model performance, the models based on resolutions comparable to modern satellite images still show considerable potential to assess larger areas where the use of digital aerial photographs is limited. The resulting spatially-explicit in-depth information can resolve the common thematic limitations of stand-alone remote sensing applications in conservation monitoring. As the method is applicable consistently across a range of habitat types, we argue that it has the potential to become a standard method for operational monitoring of priority habitats in European nature conservation.
Cherrill, A. and C. McClean. 1999. Between-observer variation in the application of a standard method of habitat mapping by environmental consultants in the UK. J. Appl. Ecol. 36
jelentés. (Habitat mapping and description of the 5x5 km sample plot “T5x5_099 Kiskunság/ Fülöpháza” in the Hungarian Biodiversity Monitoring Project. Report in Hungarian). KvVM TvH, MTA ÖBKI, Vácrátót. Bagi I
17 Bock, M., P. Xofis, J. Mitchely, G. Rossner and M. Wissen. 2005. Object-oriented methods for habitat mapping at multiple scales — Case studies from Northern Germany and Wye Downs, UK
. and C. McClean. 1995. An investigation of uncertainty in field habitat mapping and the implications for detecting land cover change. Landscape Ecol. 10: 5-21. An investigation of uncertainty in field habitat mapping and the
