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Nature Management - Habitat Restoration
What you need to know about habitat restoration
Wetland restoration Nyirkai-Hany
Why is habitat restoration necessary?
Apart from conservation aspects economical aspects increasingly play a role. Human impacts (e.g. river regulation, mining) often have side effects (e.g. decrease in ground water level, salinization, erosion) that were not counted with at the beginning of the project. Although restoration of the original ecological state is more expensive than the project itself, it is worth to restore. Cleaner environment, natural habitats may lead to significant incomes to local people through other sections (e.g. tourism, agriculture).
Types of habitat restoration
In the simplest case restoration of a given area doesn’t need any intervention because due to natural succession vegetation restores itself. This is typical for forest areas where grasslands established by former cultivation disappear completely within decades without mowing or grazing.
Often the original vegetation can still be found upon the area but in a degraded state. In this case significant advance may be achieved by forcing back the unfavorable effects. In the case of wetlands very often just restoring the original hydrological conditions proves to be enough. This type is referred to as habitat reconstruction or in some cases habitat enhancement.
Often not even traces of the original vegetation can be found on the area, so practically disappeared habitats have to be restored. In the case of abandoned strip mines this process starts with the deposition of a fertile layer of soil followed by the reintroduction of microbes and gradually vascular plants. This is usually referred to as rehabilitation.
Finally there are cases when the original habitat cannot be restored but the creation of another near-natural habitat is possible. There are also cases when so called “good” habitats evolve due to human interference. This type is called habitat creation.
Steps of habitat restoration
During implementation first physical conditions (soil layer, water, pH, etc.) required by the habitat have to be secured. Species only may be reintroduced (if necessary) into suitable habitats.
Aronson et al. (1993): Restoration and rehabilitation of degraded ecosystem in arid and semiarid lands. Restoration Ecology 1: 8-17.
Cairns, J. (1993): Is restoration ecology practical? Restoration Ecology 1.: 3-7.
Cairns, J. and Heckman, J.R. (1996): Restoration ecology: The state of an emerging field. Annual Review of Ecology and Systematics 21: 167-189.
Eades, P., Bardsley, L., Giles, N. and Crofts, A. (2003): Wetland Restoration Manual. The Wildlife Trusts, Newark
Gilbert, O.L. és Anderson P (1998): Habitat creation and repair. Oxford University Press, Oxford.
Göri Sz. et al. (1994): Vizes élőhelyek természetvédelmi kezelése a Hortobágyi Nemzeti Park területén. III. Magyar Ökológus Kongresszus összefoglalói. Szeged
Margóczi, K. (1998): Természetvédelmi biológia, JATE Press, Szeged.
Wetland restoration Nyirkai-Hany
History of the landscape
A rare and precious nesting bird of the Hanság reed is the Ferruginous Duck (Aythya nyroca) endangered worldwide. Its nesting is one of the aims of he restoration. Wet meadows provide nesting and feeding place for several, bird species of EU-wide importance such as the endangered Corncrake (Crex crex), the Montagu's Harrier (Circus pygargus) and the Short-eared Owl (Asio flammeus). Because practically there wasn’t left any open surface of water in the Hanság, the area hasn’t had any importance in bird migration for decades. This changerd fundamentally after flooding the restoration area.
The Fertő-Hanság National Park Directorate has restored much of the saline habitats near the Lake Fertő in the last decades with significant results. These experiences we used also in the Hanság during planning, construction and operation.
Creating open water surfaces upon the suitable deeper lying protected sites,
Stopping further oxidation (decomposition) of the remaining turf population,
Restoration of the marsh vegetation and water plants,
Ensuring nesting sites and undisturbed feeding places for waterbirds.Nyirkai-Hany is situated in one of the deepest lying parts of the South-Hanság. Its drainage happened relatively late, its utilization was extensive because due to lying deep, most of the year it was covered by water. The area is crossed by three significant watercourses: the Hanság-channel, the Rábca river and the Kis-metszés channel. These provide water for the restoration. Before the flooding there was no significant botanical or zoological value left, therefore the quick rise in water level could not destroy populations of protected species. The water body borders on the 286,9 ha big Bikafej Forest Reserve.
Previous to flooding the biggest part (48%) of the restoration area was dominated by Carex acutiformis and Carex riparia, besides wet (Alopecurus pratensis) and dry (Festuca rupicola) meadows (39%). To a small extent there could be found reed (4%) habitats. On 3% there were patches of wood and other habitats (4%) like farmlands. Of the protected Cirsium brachicephalum we found several tens of thousands, upon the disturbed elevations weedy patches grown over with the invasive Giant Goldenrod (Solidago gigantea). The wild boars (Sus scrofa) inhabiting the surrounding forests contributed to the change of the grassland on these patches. Soil of the Nyirkai-Hany is decomposed turf. Below the turf layer there lies a watertight layer of clay. The conservation aims were set by the Fertő-Hanság National Park Directorate. The plans for realization were prepared by the company Control Bau Kft. Beside the ecological aims a main aspect was that the landowners of unprotected areas don’t experience negative effects of the restoration – mainly inland waters. Besides, the flooded areas of the restoration could play a future role in the protection against floods.
The works started in the beginning of 2000. Two parts were flooded on 15th March and 3rd April 2001. Earth works were continued in autumn that year, the third part was flooded on 20th October 2001, at this time the area was surrendered officially.
Sluices and dams were created during implementation, water plants deriving from Hanság habitats and indigenous fish species were introduced.
The vegetation evolved after the flooding may be categorized. Some groups occur as clean populations others are rather a transition between main vegetation classes.
Bulrush (Typha): Closed and lightly dispersed populations dominated by Typha angustifolia and Typha latifolia. Among them there grow typically single stands of Alisma plantago-aquatica, Carex acutiformis, Lycopus europaeus. On some places it creates mosaic populations with sedges and tang vegetation. Previous to flooding bulrush populations were not considerable in the area, since then they are continually spreading. Great, closed bulrush patches evolved in the so-called “Bikafej” (Bullhead) area while in the “Lilomos” area rather dispersed bulrush is typical.
Sweet-grass (Glyceria): Glyceria maxima dominated populations with occasional Carex riparia, Typha angustifolia, Typha latifolia stands. Beneath them tang made up of Lemna minor and Spirodela polyrhiza is typical. Their populations gradually decrease in the area. At the end of 2005 populations remained only in the area „Nyugati-Mór rétek” (Western Moor Meadows) and beside the dams.
Reed (Phragmites): Phragmites australis dominated closed and dispersed reedy populations. On some places two levels are present, the lower made up of Carex acutiformis and Carex riparia. Besides, some stands of Typha angustifolia, Typha latifolia, Sparganium erectum and Solanum dulcamara occur. Reed populations are expanding in the area.
Phalaris: Habitats made up of Phalaris arundinacea with little diversity. In areas temporarily covered by water they mingle with sedge and bulrush populations.
Open water: Areas without or with few (1-2%) vegetation. Their extent is growing continually on the area.
Tang vegetation: One- or two-level habitats dominated by tang species. Characteristic, common species are Ceratophyllum demersum, Myriophyllum spicatum, Najas marina, Persicaria amphibia, Lemna minor and Utricularia vulgaris. Their populations are expanding in the whole area continually.
Other vegetation: This category includes non-marsh habitats. These are for example habitats of dry places (islands, dams). Natural grasslands are dominated by Alopecurus pratensis, Festuca arundinacea and Festuca rupicola, but weedy habitats dominated by Calamagrostis epigeios, Solidago gigantea and Echinochloa oryzoides also occur.In the first year after flooding (in 2001 on the areas „Liliomos” and „Bikafej”, in 2002 on „Nyugati-Mór-rétek”) species intolerant to continuous or temporary water coverage quickly disappeared. Vegetation classified as “other” remained practically only on dry places. An exception was only the Wood Small-reed (Calamagrostis epigeios) that remained on places with temporary, shallow water coverage.
Sedge communities (Carex) tolerated in the first two years high water coverage, but completely disappeared in the third year from deepwater places. In shallow water they are continually expanding and on several dry places they grow as well. On former plough-lands they compete with bulrush, slowly displacing it.
Bulrush populations (Typha) were expanding after flooding, especially in shallow water, and created in the second year already dense, closed populations. Expansion may be witnessed also in mid and deep water, here dispersed occurrence is characteristic rather.
Sweet-grass populations (Glyceria) were present prior flooding in the deepest parts. Their presence declined sharply in the second year.
Populations of reed (Phragmites) are dying off where they occurred prior to flooding but spread in shallow and middle water.
Phalaris tolerated in the first year water coverage but from the second year on were decreasing and in the fifth year disappeared from the area.
Open water patches are expanding continually, mainly on the former habitats of sedge and sweet-grass populations.
The newly appearing tang populations are expanding as well in all water depths. In the first two years mainly Myriophyllum spicatum, Ceratophyllum demersum and Persicaria amhipbia dominated, but in the third year Utricularia vulgaris also appeared. Latter species forms at some places great populations several hectares wide. Najas marina is spreading as well. In the beginning it appears as a second level, mainly beneath Myriophyllum spicatum és and Ceratophyllum demersum, but later often displaces them.
Changes in bird populations
Te population changes of frequent birds are more difficult to investigate. On an area 33,5 ha big we found 175 coot (Fulica atra) nests in 2002, that projected a coot density of 5,22 pairs/ha.
According to a detailed survey done 2002 nine of the species present in the area may be told persistent, being present at the time of ice-coverage as well. Further nine species occur occasionally (less than 10 observations). Dominant species according to numbers of individuals are the Mallard (Anas platyrhynchos), the Coot (Fulica atra) and the Greylag Goose (Anser anser), latter was formerly observed only occasionally in the Hanság.
Of the species building their nests in the vegetation characteristic species are the Little Grebe (Podiceps ruficollis), the Great Crested Grebe (Podiceps cristatus), the Ferruginous Duck (Aythya nyroca) and the Common Pochard (Aythya ferina). The Bitterns (Botaurus stellaris) and the March Harrier (Circus aeruginosus) are present with a few nesting pairs. The quick settling of the Red-crested Pochard (Netta rufina) is noteworthy, being an extremely rare breeding bird in the country except on the Lake Fertő.
The number of species was higher during spring migration from the end of April to the end of June. In this period 30-40 species were present with a peak (40) in the first week of May. In autumn the number of species was only half of this.
The maximum number of individuals observed at a time was also highest in spring, from the end of March to the middle of April it regularly exceeded 3000. Total numbers of individuals counted in the summer and autumn didn’t even get near that. It has to be mentioned that in 2002 there was no significant migration of wild geese in the area, in the following years the total number of wild geese counted in October and November was several thousands.
A joint Hungarian-Austrian project monitors the regional migration of wild goose species that was expanded to the Nyirkai-Hany area. It showed that the number of geese – Greylag Goose (Anser anser), Greater White-fronted Goose (Anser albifrons) and Bean Goose (Anser fabalis) – grew over the years, meaning that a new resting place evolved in the Kisalföld region. The Barnacle Goose (Branta leucopsis), the Red-breasted Goose (Branta ruficollis) and the endangered Lesser White-fronted Goose (Anser erythropus) were observed several times as well.
The number of shorebird species and individuals was low, explained by the relatively deep water. In the time of spring migration the Lapwing (Vanellus vanellus) and the Ruff (Philomachus pugnax) dominate, other Limicoles appear occasionally. In 2001, the first year of flooding the Greenshank (Tringa nebularia) appeared in unusually high numbers (max. 54 individuals), later this was not noted. A greater flocking of shorebirds may only be expected at a low water level in the future.
|Magyar név||Latin név||2001||2002||2003||2004||2005|
|Nagy kócsag||(Egretta alba)||0||0||1||6||3|
|Vörös gém||(Ardea purpurea)||0||2||40||10||30|
|Bütykös hattyú||(Cygnus olor)||0||5||6||4||6|
|Nyári lúd||(Anser anser)||0||5||7||13||30|
|Kis lile||(Charadius dubius)||?||9||0||0||0|
|Küszvágó csér||(Sterna hirundo)||25||15||15||10||20|
Within the wetland reconstruction program of the Hanság the directory of the Fertő-Hanság National Park plans further floodings with the same goals as in the case of Nyirkai-Hany. The next step is the re-flooding of Osli-Hany, an area of 1322 ha.
Further information regarding the area
Literature from the area
1. Pellinger, A. (ed.) 2001. Hansági vizes élőhely rekonstrukció, Fertő-Hanság Nemzeti Park (Restoration project of the wetland habitat of the Hanság -Fertő-Hanság National Park). Technical Report, unpubl. Sarród.
2. Margóczi, K., Takács, G., Pellinger, A. & Kárpáti, L. (2002): Wetland reconstruction in Hanság area (Hungary), Restoration Newsletter 15:14-15.
3. Takács, G. & Margóczi, K. (2002): A dél-hansági élőhelyrekonstrukciók (Fertő-Hanság Nemzeti Park) biodiverzitás monitorozása (2001), Kutatási jelentés
4. Takács, G. (szerk) (2003): A dél-hansági élőhelyrekonstrukciók komplex ökológiai monitoringja 2003, Kutatási jelentés, pp 139.
5. Margóczi, K., Takács, G. & Körmöczi, L. (2004): Vegetation monitoring of the wetland reconstruction area in Hanság (Hungary) (A hansági vizes élőhelyrekonstrukció növényzetének monitorozása (Magyarország)), 7th INTECOL International Wetland Conference 25 - 30 July 2004 in Utrecht, pp 196.
6. Margóczi K., Takács G. and Körmöczi L.(2005): Vegetation monitoring of a reconstructed fen in Hanság, Hungary. In: Middleton, B. and Grootjans A.: Fen and Fen/Sedge Meadow Management and Research Perspectives: An Overview of the Symposium. Springer (megjelenés alatt)
7. Takács, G. & Margóczi, K. (2005): Small scale and large scale monitoring of vegetation changes in a restored wetland (A vegetáció változásainak kis és nagyléptékű monitorozása helyreállított vizes élőhelyeken), W3M Conference for Wetlands: Monitoring, Modelling and Management, 22 - 25 September 2005 in Wierzba, p. 40.
8. Temesszentandrási, Zs. (2004): A dél-hansági vizes élőhely-rekonstrukció vegetációtérképezése. Diplomamunka, Budapesti Közgazdaságtudományi és Államigazgatási Egyetem Kertészettudományi Kar Növénytani Tanszék, Budapest
9. Timmermann, T., Margóczi, K. Takács, G. & Vegelin, K. Restoring Peat Forming Vegetation By Rewetting Species-Poor Fen Grasslands: The Role Of Water Level For Early Succession (Tőzeglápok vegetációjának helyreállítása fajszegény mocsárrétek elárasztásával: A vízszint hatásai a szukcesszió kezdetén), Applied Vegetation Science (megjelenés alatt)
10. Bátori Z. (2005): Az elárasztás hatása a vegetációra a dél-hansági élőhelyrekonstrukció területén. Diplomamunka. SZTE Ökológiai Tanszék, Szeged.
11. Bátori Z. (2005): A vegetáció változásának vizsgálata egy elárasztott területen. A dél-hansági élőhelyrekonstrukció. XVII. Országos Tudományos Diákköri Konferencia, Biológia szekció, Pécs (első helyezet).
12. Pellinger A. és Takács G. (2006): Nyirkai-Hany vizes élőhelyrekonstrukció - Fertő-Hanság Nemzeti Park. Ismertető: 14p.