Presentation on theme: "Vegetation monitoring of the wetland reconstruction area in Hanság (Hungary) Katalin Margóczi (University of Szeged, Department of Ecology) Gábor Takács."— Presentation transcript:
Vegetation monitoring of the wetland reconstruction area in Hanság (Hungary) Katalin Margóczi (University of Szeged, Department of Ecology) Gábor Takács (Fertő-Hanság National Park Directorate) László Körmöczi (University of Szeged, Department of Ecology)
The hiStory of Hanság Till the 19th century Hanság was a ha large wetland, connected with the Lake Fertő. Lake Fertő (Neusiedler see) Wien Bratislava Hanság Today only the Fertő is indicated as wetland on the map.
There are tree plantations, meadows, ploughlands on the former fen area (outlined by red line) The blue line shows the outline of wetland reconstruction.
The area of wetland reconstruction (red line) on the military map from The ancient Hanság was a large, mostly floating fen, with small lakes, sedges, reeds and some alder forest patches.
In the main drainage channels can be seen on the map, and mainly wet meadows instead of floating fen The drastic drying-out of the fen was successful only in the early 20th century, using machines to dig channels. Secondary meadows formed in the place of the fen, and most of the lakes disappeared. A large part of the area was ploughed, afforested, and peat mines were opened.
Nature protection In spite of drainage and a lot of human disturbance, the Hanság could save a relatively large part of its natural values. Patches of natural vegetation survived in the wet meadows and forests, and the aquatic communities partly survived in drainage channels. Hanság became a protected natural area in 1976, and since 1994 it has been a part of the Fertő-Hanság National Park. Hottonia palustris in a channel
The most serious deficiency of the protected area is the very few remaining wetland, so the National Park Directorate decided to restore wetland areas. Restoration of a larger area of the former fen by closing the channels would be nice, but present human activities, demands and the changes of hydrology make it impossible. Technical possibilities, safety, ownership and economical criteria were considered in priority when choosing the 400 ha area to be flooded. The restoration was supported by Hungarian and Dutch Governments
The main goals of restoration: To create wetland with open water, suitable habitat for water-birds and fen-plants. To have a model area, and to get experiencies of rewetting. To decrease invasive plant species (Solidago gigantea).
A habitat map were made before flooding. Large sedges (57%) (Carex riparia, C. acutiformis), and wet meadows (28%) (Alopecurus pratensis, Festuca arundinacea) were the dominant vegetation types and some reeds (5%) (Phragmites australis, Glyceria maxima) also occured.
Technical aspects of reconstruction Dikes were built around the planned wetland pools, and water was transported by gravitation through sluices from the river Rábca and the channel Kismetszés. The 1st and 2nd unit was flooded in spring 2001, and the 3rd unit in autumn.
The water-level is intended to keep constant. The water depth is between cm. The year 2001 and 2003 was very dry, so the water level was about 20 cm lower.
Aerial photos from the first year of flooding
The landscape of the reconstructed area is really beautiful, it is one of the main attractions of the National Park.
Autumn wiev of sedges Open water area Tussoks of sedgesPersicaria amphibia field
Monitoring methods Small scale monitoring: 5x5 m phytosociological relevés along 21+4 permanent transects every year. Large scale monitoring: vegetation mapping using aerial ortophotos in every 3rd year, and developing GIS database.
Location of permanent transects
Small scale monitoring method: permanent transects The end of the transects were marked by wooden sticks, and positioned using GPS. The percent cover of plant species were recorded in 20 pieces of 5x5 m quadrates along each transect. 100 m 5 m
Results of small scale monitoring Each of the 420 relevés were categorized into vegetation types, named according to the dominant species. The vegetation is slightly different in the three units of restoration area.
The main vegetation categories Water-plants Glyceria (maxima) Phragmites (australis) Typha (latifolia, angustifolia) Sedges (Carex acutiformis, C. riparia)
The depth of the water is one of the main environmental factor affecting vegetation development Finer categories, differentiated by cluster analysis
Changes of vegetation in the first 3 years after flooding Dryland vegetation disappears (2nd year) Typha increases Open water and water-plants increase Sedges decrease (3rd year)
The permanent transect method is suitable for fine detection of local vegetation changes Sequence of individual relevés Species Percent cover of species Sample
Transect 1.2 Glyceria overgrows in the deep water, Carex survives at 50 cm water depth Water depth (cm)
Transect 1.5 Glyceria overgrows Phalaroides, but disappears in the 3rd year in 80 cm deep water 2003 Water depth (cm)
Transect 2.4 Carex disapperars in the 3rd year from 80 cm deep water, Persicaria grow up in the open place Water depth (cm)
Transect 2.3 Typha latifolia outcompetes Carex riparia in the 3rd year at cm water depth Water depth (cm)
Large scale monitoring Parameters of the aerial photograph: Service: Telecopter Kft. Date of flight: (12:00 – 12:15) Film material: K color III 2444 Flying height: 1200m Camera: Wild RC-10 (f=153,1mm) Overlap: 60% Resolution: 1 m
Processing of the aerial photoghraph Scanning with 18μm resolution and 16 bit color depth. Ortorectification with field reference points by ERMAPPER 6.1 and DIGITERRA (Hungary) softwares. Outline the possible patch contours in the computer.
Developing GIS data base (ESRI ArcView 3.2) Identification and correction in the field. (vegetation category, main species and their cover, total vegetation cover) Data processing by raster analysis (One pixel is 1x1 m) GRID statistics
Results of large scale monitoring Detailed description of vegetation categories. Thematic maps about the restored area. Statistics.
Detailed description of vegetation categories Code:CaCr National habitat category: B5 Association:Caricetum acutiformis és Caricetum ripariae Alliance:Magnocaricion Short decription:Sűrű, általában erősen zárt magassásos (60-100%). A Carex riparia és a Carex acutiformis változó arányban fordul elő. Mellette a gyékények és egyéb fajok csak max. 1-5%-ban fordulnak elő. A sások helyenként zsombékolnak. Species: Dominant:Carex riparia, Carex acutiformis Subdominant:Typha angustifolia, Typha latifolia Abundant:Lythrum salicaria, Phalaroides arundinacea, Typha angustifolia, Typha latifolia, Phragmites australis Sample 62 vegetation types were distinguished and described
Thematic maps about the restored area. Total plant cover above the water level
Total plant cover under the water level
Raster statistics Area (in ha) of vegetation categories in the whole restored area in 2003.
Do the permanent transects represent appropriately the whole restored area ? Glyceria is overrepresented Water plants are underrepresented
Evaluation of restoration Natural wetland communities are developing in the area. The landscape is beautiful. It is a very important breeding and feeding area of birds. (Zoological monitoring is being made as well!) The hydrology is considerably different from the original situation. Natural communities are not the same, than before drainage of the ancient fen.
Attributes of restored ecosystems (SER 2002) Present situation in Hanság restoration project 1.The restored ecosystems contains a characteristic assemblage of the species that occur in the reference ecosystem The dominant species after flooding were abundant before drainage as well. 2. The restored ecosystems consist of indigenous species There are no abundant exotic species, Solidago gigantea decreased strongly after flooding. 3. All functional groups are represented.Certain groups are underrepresented (e.g. hydato-helophyta species) 4. The physical environment is capable of sustaining reproducing populations. The water quality is not very good. 5. The restored ecosystem apparently functions normally Further study is necessary to find out. ? 6. The restored ecosystem is suitably integrated into a larger ecological matrix. The new reconstructed wetland improves the landscape level habitat diversity. 7. Potential threats have been eliminated.Desiccation have been eliminated, but eutrophication not. 8. The restored ecosystem is sufficiently resilient. The revegetation was spontaneous, so resilience is quite good. 9. The restored ecosystem is self- sustaining. Further study is necessary to find out. ? Evaluation of restoration according to the SER Primer
Future The National Park is ready to follow wetland restoration! Forestry and agriculture cause severe soil degradation in this area, so wetland restoration would become soon the only logic land use in Hanság! The change of the water management in the whole area of Hanság is necessary for saving the natural values.
Katalin MARGÓCZI Gábor TAKÁCS László KÖRMÖCZI Thank you for your attention!