The Danube in Serbia – Ecological Status and Management Issues
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Transylv. Rev. Syst. Ecol. Res. 12, (2011), "The Wetlands Diversity" 91 THE DANUBE IN SERBIA – ECOLOGICAL STATUS AND MANAGEMENT ISSUES Ana BORISAVLJEVIC * * University of Belgrade, Faculty of Forestry, Kneza Viseslava 1, Belgrade, Serbia, CS-11030, [email protected], [email protected] KEYWORDS: flora, fauna, ecological status, bioindicators, hydromorphological alterations, management, Danube. ABSTRACT Many stretches of the river Danube have lost their ecological value in recent decades as a result of anthropogenic pressure from intensive agriculture, new infrastructure projects, more intensive navigation and the construction of hydro-power plants. The greatest alterations have happened in recent decades also in the investigation area, which is a part of the Middle Danube, from 1,433 to 845 km, and extends into Serbia. The content of this review paper is based on the analysis and use of topographical maps, data on waterline and discharges for five hydrological stations on the Danube in Serbia, analysis of the floral and faunal bioindicators, and a review of relevant literature. We describe indications of ecosystem alterations, following which we offer discussion on management issues, and make recommendations and comments. This paper synthesizes existing knowledge on the Danube in Serbia and, at the same time, warns of proposals that can become real projects that may have extreme adverse consequences for the Danube ecosystem. ZUSAMMENFASSUNG: Die Donau in Serbien ‒ ökologischer Zustand und Managementfragen. In den letzten Jahrzehnten haben viele Abschnitte der Donau unter dem Druck menschlicher Tätigkeiten durch intensive Landwirtschaft, neue Infrastrukturprojekte, intensivere Schifffahrt und den Bau von Wasserkraftwerken ihren ökologischen Wert verloren. Derartige, große Veränderungen fanden in den letzten Jahrzehnten auch in dem untersuchten Donauabschnitt statt, der sich als Teil der mittleren Donau in Serbien von Strom-Kilometer 1,433 zu 845 erstreckt. Der Inhalt dieser Abhandlung beruht auf einer Analyse topografischer Karten, von Daten betreffend Wasserstands- und Abflussverhältnisse fünf hydrologischer Pegelstationen an der serbischen Donau sowie von Bioindikatoren aus Flora und Fauna und einer unter Berücksichtigung relevanter Fachliteratur. Neben der Hervorhebung der ökologischen Veränderungen und einer folgenden Diskussion über Managementfragen, werden auch umsetzbare Empfehlungen und dazu entsprechende Anmerkungen gegeben. Die Arbeit liefert eine Synthese der Kenntnisse über die Donau in Serbien und warnt gleichzeitig vor Ideen, die reelle Projekte werden können und extreme gegensätzliche Konsequenzen für das Donau-Ökosystem haben können. 92 A. Borisavljevic – The Danube in Serbia - ecological status and management issues (91 ~ 100) REZUMAT: Dunărea în Serbia ‒ starea ecologică şi probleme de management. În ultimele decenii multe sectoare ale Dunării şi-au pierdut valoarea lor ecologică datorită presiunilor antropogene din partea agriculturii intensive, noi proiecte de infrastructură, navigaţie mai intensivă şi construcţii de hidrocentrale. Astfel de schimbări remarcabile au avut loc în deceniile trecute şi în aria de investigaţii, care e parte a Dunării mijlocii, de la kilometrul fluvial 1,433 la 845 în Serbia. Conţinutul prezentei lucrări se bazează pe analiză şi folosirea hărţilor topografice, analiza datelor privind cotele apelor şi a debitelor pentru cinci staţii hidrometrice ale Dunării din Serbia, a unor bioindicatori ai florei şi faunei, precum şi a literaturii relevante de specialitate. Pe lângă prezentarea alterărilor ecosistemului şi a discuţiilor asupra problemelor de management, sunt date de asemenea recomandări aplicabile şi unele remarci adiţionale. Lucrarea sintetizează cunoştinţele existente asupra Dunării în Serbia şi în acelaşi timp atrage atenţia asupra ideilor care pot deveni proiecte reale şi care au consecinţe extrem de adverse pentru ecosistemul Dunării. INTRODUCTION By enacting the Water Framework Directive in 2000, the EU improved its water policy and stated that rivers, lakes, groundwater and coastal areas should achieve “good ecological status” by 2015 as a base for the sustainable use of water resources across Europe (EU 2000, article 4; WWF 2001). This new water policy was triggered by rapid deterioration of water quality and degrading river ecosystems. However, reaching this goal is a great challenge in environmental protection for the EU member states. Floodplain ecosystems have important functions, indicating ecological status of the entire river and providing water resources protection (EU 2000). Barrett (1999) underscores that wetlands and floodplains are used for water quality improvement as a valuable ecoengineering application. River floodplains are recognized as flood retention areas and natural sinks of nutrient load (Haycock et al., 1993; Barrett, 1999; Mölder and Schneider, 2010). Moreover, floodplains can be core areas for the restoration of whole, degraded riverine landscapes (Zsuffa and Bogradi 1995). However, surface connectivity between stream and riparian zones has been reduced and floodplains have been fragmented by channelizing and dredging river beds (Tockner et al., 1998). About 80% of the historical floodplain in large rivers has been lost during the last 150 years mainly through significant man-made hydromorphological alterations (WWF 1999; ICPDR 2005) The Danube River has the most international basin in the world; it is a transit navigable line of international importance and has experienced a long history of human occupation (JDS 2008; Sommerwerk et al., 2009). Many reaches of the Danube have lost their ecological value during the past decades due to anthropogenic pressure by intensive agriculture, new infrastructure projects, intensified navigation, construction of hydropower plants, and flood protection schemes (dykes). Many of these projects and activities are in conflict with the principles and objectives of river ecosystem protection. For instance, the construction of dams, such as Gabcikovo and Iron Gate, has caused severe and adverse changes upstream and downstream in river ecosystems (Perisic, 2001; Klaver et al., 2007). However, there are still river stretches quite close to the natural state. Gornje Podunavlje in Serbia, Kopacki Rit in Croatia, Gemenc and Béda-Karapancsa in Hungary, crosscut by state- political borders, are parts of a huge floodplain ecosystem area. As very high biodiversity has been recorded, they are considered as an integral area, protected and listed as the Reserve of Biosphere, “Amazon of Europe”. Transylv. Rev. Syst. Ecol. Res. 12, (2011), "The Wetlands Diversity" 93 The Serbian stretch in the Middle Danube is 588 km long. Most part of the territory of the Republic of Serbia (81,000 km² or 92%) belongs to the Danube River basin or to the Black Sea catchment (Ministry and Institute Jaroslav Cerni 2001). After ratifying the Framework Agreement on the Sava River basin and the Danube River Protection Convention in 2002 and 2003, respectively, Serbia became a member state of the ICPDR and the ISRBC, contributing to the international aims regarding sustainable and integrated management of the Danube River and the Danube region. The Republic of Serbia ratified the Ramsar Convention and has nine Ramsar sites so far (only one of them, Gornje Podunavlje is on the Danube). Determining wetland areas in Serbia as possible Natura 2000 Network of the EU is in progress. It is necessary to identify other valuable stretches of the Danube in Serbia as well and to inform the public to promote the conservation and protection of these areas. This paper ensued from the research focusing on review, analysis and synthesis of hitherto data, published studies and reports which observed the Danube at the whole course or some parts of the Serbian stretch. Beside the aim to contribute to the national status assessment for the Danube, this work has an intention to underline the significance of floodplains and support future research on floodplains and their protection in Serbia. When considering the Danube stretch in Serbia, we discuss about three main issues: ‒ pointing all the main changes that have happened on the Danube in Serbia emphasizing the ecological alterations; ‒ management issues and applicable recommendation. MATERIALS AND METHODS Study area The river basin of the Danube, which has a total length of 2,850 kilometres, can be divided into three main sections and the delta. The Upper Danube extends from the source in the Black Forest in Germany to the confluence with the Morava River near the Slovakian capital of Bratislava, the Middle Danube extends from Bratislava to the breach valley of the Iron Gate (border between Romania and Serbia), and the Lower Danube is formed by the Romanian-Bulgarian lowlands and the large Romanian floodplains downstream of Călăraşi- Silistra (border between Romania and Bulgaria). Finally, the Danube discharges into the Black Sea; the delta is the second largest in Europe (Schneider et al., 2009; Sommerwerk et al., 2009). The investigation area is a part of the Middle Danube, from 1,433 to 845 rkm (i.e. from Bezdan to the mouth of the Timok River) which extends in Serbia. This stretch, in terms of the alterations of waterline and discharge, hydromorphology, species diversity changes on the one hand and pollution/water quality, dredging and impact of other activities, on the other hand, are studied. The Tisa River and the Sava River, as the most important tributaries, have the confluences in