Dynamic Danube Natural Values

Funded by the European Union

c/o Duna-Ipoly National Park Directorate

1121 Budapest, Költô utca 21., Hungary

The natural sections of the Danube River and its large wet-lands are part of our common European natural heritage.Numerous protected areas and NATURA 2000 sites alongthe course of the Danube reflect the high value of thistransnational ecosystem and represent unique natural areas.

River dynamics and natural morphological processes arethe key for the long-term preservation of the Danube Riverecosystem. Intact water and sediment regimes, river dynam-ics and adequate space for the river determine the greathabitat variety and species richness – qualities which arestill characteristic for parts of the Danube floodplains.

Human activities (e.g. agriculture, forestry) usually require sta-ble hydro-morphological circumstances rather than dynamic,natural conditions. Regulation of meanders, cutting-off of sidearms, embankments, dykes and other man-made hydro-morphological alterations have changed the abiotic param-eters and, ultimately, the healthy status of the habitats. Damshave dramatically impacted longitudinal continuity and sedi-ment transportation, resulting in, for example, riverbed ero-sion on most Danube sections. Waterway transport projectswhich are intended to improve conditions for navigationroutes can also be seen as a risk.

The formation of “new” habitats in the early stages of succes-sion, such as steep loam walls, gravel islands or large scalesand banks could be done only through permanent relocationof sediments, by erosion and accumulation. Blocking river dy-namics stops these initiating processes; due to ongoing suc-cession, these characteristic habitats of natural rivers havebecome extremely rare. Consequently, the conenose relatedto these dynamic habitats is highly threatened on a Europeanscale, stressed also by the highest rate of extinct species ofall habitat types along the Danube.

Accordingly, both the conservation as well as the restora-tion of river dynamic processes and habitats is a priority fornature conservation on the Danube River. Protected areashave an outstanding role, conserving valuable sites and beinga key driver for the revitalization of side arms, restoration ofriver banks and supporting concepts for ecological river man-agement.

The Danube River is one interrelated ecosystem. Hydro-mor-phology, river dynamics and sediment balance can be tackledonly by a Danube-wide approach. Hence, DANUBEPARKSinitiated a transnational study to describe the situation on aDanube-wide scale using two indicator species: the LittleRinged Plover and the Sand Martin. The aim of the studyis to identify hot spots of these species as priority areas forconservation of dynamic habitats, as well as gaps in their dis-tribution to highlight their needs and the potential for riverrestoration.

Both species are closely linked with and adapted to theseriver dynamic habitats. The Little Ringed Plover needs bareor sparsely vegetated gravel or sand banks, laying its brilliantlydisguised eggs on blank sediments. However, natural riversections without “strong” regulation and inducing such ex-tensive gravel and sand banks have shrunk significantly overthe last two centuries, especially on the Upper Danube. Onceabundant along the Danube, the Little Ringed Plover hasbeen displaced from its natural environment by human impact.

The Sand Martin needs steep natural river banks to burrowits nests. Breeding colonies indicate sites where natural lateralerosion is still active. Due to the high number of characteristicinsects, different threatened bird species and other organismsdependent on this habitat type; these sites are also of highconservation concern.

Both species were originally widespread along the Danube andare still relatively common in the Danube countries thanks totheir adaptation to artificial secondary habitats. Being adaptedto dynamic habitats, Little Ringed Plover and Sand Martin reactquickly to structural changes and provide good and quick in-dication of impacts on their habitats, whether positive (e.g.restoration actions) or negative (e.g. river regulation). Finally,the birds are easy to recognize, to identify and to monitor. Asthey are attractive species, monitoring could be shared withinterested public, press and stakeholders. All this qualifies theLittle Ringed Plover and the Sand Martin as perfect indicatorspecies and as drivers for river dynamic processes.

Introduction

DANUBEPARKS – Danube RiverNetwork of Protected Areas

Based on existing co-operation, DANUBEPARKS –The Danube River Network of Protected Areas – wasestablished as a platform for continuous transnationalco-operation of numerous Protected Area administra-tions from almost all of the Danube countries. Between2009 and 2012, Danube-wide monitoring in the fieldsof habitat management, river restoration, conservationof Danube flagship species and Danube nature tourismwere carried out; joint Danube-wide conservation con-cepts were also developed and strategic pilot actionsimplemented. DANUBEPARKS is funded within theframework of the EU funding programme ETC - SouthEast Europe (SEE) and is a “flagship project’’ in the EUStrategy for the Danube region.

www.danubeparks.org

www.southeast-europe.net

www.danube-region.eu

c/o Duna-Ipoly National Park Directorate1121 Budapest, Költô utca 21., Hungary

Scientific Coordination of Monitoring: Matthias Schmidt,BirdLife AustriaCoordination of Monitoring: Gyula Kiss, kiss.gyula@dinpig.hu

Maps created with Natural Earth, created by Matthias Schmidt, BirdLife Austria

Monitoring Observers:Germany: A. Schuhbauer; Austria: M. Schmidt, H. Frötscher,M. Schindler; Slovakia: D. Krivošík, D. Turcáni, S. Keresztesová,A. Kürthy; Hungary: Á. Selmeczi Kovács, A. Füri, K. Sipos, P.Csonka, Z. Hegyi, A. Nagy, B. Tóth, Gy. Kiss, I. Staudinger,T. Bíró, Z. Kovács, A. Mórocz, T. Gruber; Serbia: B. Grubac,S. Barbulovic, V. Jovanovic, Z Milovanovic, D. Jankulovic, M.Tucakov, Jankovic, Stojnic, Ham; Bulgaria: V. Koev, P. Shurolinkov,G. Daskalova; Romania: I. Cobzaru, F. Bodescu, D. Damuc

www.danubeparks.org

Photos: D. Grlica, G. Frank, H. Frötscher, F. Kern, C. Manzano, C. Roland, M. Schmidt, BROZ, B. Tóth, M. Tucakov, Z. Milovanovic, I. Cobzaru, Á. Selmeczi Kovács

Layout: Michael Kalb - www.michaelkalb.at, Kiss MajaPrinting: Szó-Kép Nyomdaipari Kft., www.szo-kep.hu

Printed in 2000 copies. February 2012.Produced by environmentally friendly technologies and materials.

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During the 2011 breeding season the whole Danube from theBlack Forest to the Black Sea was surveyed for breedingpairs of Little Ringed Plover and Sand Martin. Nine ProtectedArea administrations from seven Danube countries took partin the monitoring and covered more than 3,100 kilometres,including the branches of the islands of BaltaIalomitei andGreat Braila Island. Two surveys of the study area (each onein May and June) were completed; in the upper-most part ofGermany and in a section in Serbia only one survey tookplace. The monitoring was mainly done by small boats andthe survey was limited to the main stream of the Danube. Allsuitable habitats for both species were investigated; artificialareas like sand quarries were not considered in the analysis.For each site the number of birds and breeding pairs werecounted or estimated by the observers. Details of the habitatwere noted. For the Little Ringed Plover, habitat was classi-fied according to one of six possible types (see graph).

Considering the compacted methodology with only two sur-veys, the maximum numbers of territories per location wereused for the analyses. For visualization, the results weresummed up for twenty-kilometre sections. The first survey inMay was distinguished by a very low water level on the wholeDanube, which results in very good breeding conditions es-pecially for Little Ringed Plover. On the second run the waterlevel was more heterogeneous and so there were variousconditions in the different sections. Due to the direct influenceof the water level on the population size of Little RingedPlover, follow-up surveys are planned for the evaluation of theresults, although first local verification of the data fits in wellwith the results of local monitoring programmes.

LITTLE RINGED PLOVER (CHARADRIUS DUBIUS)The Little Ringed Plover is a widespread, long distance migratory bird of the wadergroup. It breeds in Europe from the end of March to the end of July. Primary breedinghabitats are bare or sparsely vegetated sand or gravel structures of freshwater areas.Due to river regulation and damming (in particular for hydro power), this habitat typeand its characteristic conenose is one of the most threatened in Europe. Althoughthe Little Ringed Plover was faced with a decline in central Europe, the species man-aged to use artificial nesting sites such as quarries or fishponds. Today, more than90% of its European population breeds in secondary habitats.

SAND MARTIN (RIPARIA RIPARIA)The Sand Martin is a common species in Europe and occurs in most European countriesas a breeding bird. The European population winters in tropical Africa and the firstbirds return to Europe in March, breeding from May to July in colonies of only a fewup to several thousand pairs. Colony sites are mostly located near river or other fresh-water sites and nests are bored into vertical sand or loam walls, basically resultingfrom lateral erosion of dynamic rivers. This habitat structure is shared by Sand Martinwith a wide range of rare species; its loss due to river regulation was compensatedby occupying artificial breeding habitats such as sand quarries.

Monitoring 2011

gravel bank

gravel

sand

vegetation

land

river bank (sand) river bank (gravel)

sand island gravel island sand bank

During the breeding season, the Little Ringed Plover can befound along the whole Danube. In total, 369 territories of LittleRinged Plover on 218 nesting sites were recorded during thismonitoring. The highest densities were detected betweenVienna and Bratislava, up to 27 territories/20 km (river-km1,900 to river-km 1,880) in the free flowing section in theDonau-Auen National Park. The border section betweenRomania and Bulgaria provides good breeding conditionsover a long distance and, therefore, is of highest importancein terms of number of territories.

Upstream of Vienna this species breeds only in low densitiesdue to the high degree of regulation and embankment. Thegood size of the breeding population along the free flowing

section between Straubing and Vilshofen (river-km 2,320 toriver-km 2,250), and the fact that small revitalized areas werealso colonized, underline the high potential of the gravel-dominated Upper Danube for this species – before hydro-morphological alterations most probably the optimum habitatalong the Danube.

The high density along the “old” original Danube arm (up to14 breeding pairs/20 km) parallel to the “hydropower chan-nel” of Gabcíkovo hydropower plant – where the Little-ringedPlover is totally missing – stresses the fundamental negativeimpact of dams on this species. Also noticeable is also thegap in the distribution found in the back water of the Djerdaphydro dam, upstream of the Iron Gate.

The Little ringed Plover shows a clear preference for islandstructures; more than three-quarter of the territories werefound on these structures (see graph). In particular, sand is-lands in the Lower Danube are of high importance for thisspecies, as are gravel islands and banks. Consequently, thehighest densities along the Lower Danube were found in thesection between Nikopol and Ruse (river-km 500 to river-km600), which offers huge complexes of sand islands andbanks, providing habitat for 34 breeding pairs on 20 sites.

For natural, river morphological reasons, the Little RingedPlover seems to be rare in the area of the Great Braila Islandand the Danube Delta is lacking in suitable habitats for thisspecies.

Population, distribution and habitat of Little Ringed Plover

gravel bank21%

river bank(not classified)5%

island(not classified)3%

not classified1%

river bank (sand)8%

river bank (gravel)8%

sand island26%

others9%

gravel island22%

sand bank6%

Types of breeding habitat of Little Ringed Plover

Germany

Germany-Austria

Austria

Austria-Slovakia

Slovakia

Slovakia-Hungary

Hungary

Serbia-Croatia

Serbia

Serbia-Romania

Bulgaria-Romania

Romania

Total

(658 km)

(29 km)

(321 km)

(8 km)

(22 km)

(142 km)

(275 km)

(138 km)

(220 km)

(230 km)

(471 km)

(ca. 600 km)*

> 3100 km

22

0

24

0

0

37

36

10

15

5

54

15

218

25

0

45

0

0

62

48

26

33

17

88

25

369

6.8

0.0

12.2

0.0

0.0

16.8

13.0

7.0

8.9

4.6

23.8

6.8

100

0.04

0.00

0.14

0.00

0.00

0.44

0.17

0.19

0.15

0.09

0.19

0.04

0.12

1.14

1.88

1.68

1.33

2.60

2.20

3.40

1.63

1.67

1.69

Counrty / Section Breedingsites (n) (n)

Territories(%) per/km

Mean territoriesper site (n)

*Incl

udin

g Is

land

Bal

ta la

lom

itei,

Grea

t Bra

ila Is

land

and

Sfâ

ntu

Gheo

rghe

bra

nch

TYPICAL LITTLE RINGED PLOVER HABITATS

at upper Danube at middle Danube at lower Danube

TYPICAL SAND MARTIN HABITATS

at middle Danube at lower Danube

Breeding of Sand Martin along the Danube

Germany

Germany-Austria

Austria

Austria-Slovakia

Slovakia

Slovakia-Hungary

Hungary

Serbia-Croatia

Serbia

Serbia-Romania

Bulgaria-Romania

Romania

Total

(658 km)

(29 km)

(321 km)

(8 km)

(22 km)

(142 km)

(275 km)

(138 km)

(220 km)

(230 km)

(471 km)

(ca. 600 km)*

> 3100 km

0

0

0

0

0

1

2

2

6

4

18

49

82

0

0

0

0

0

60

66

350

8466

1330

7321

5224

22 817

0.0

0.0

0.0

0.0

0.0

0.3

0.3

1.5

37.1

5.8

32.1

22.9

100

0.0

0.0

0.0

0.0

0.0

0.4

0.2

2.5

38.5

5.8

15.5

8.7

7.4

0

0

0

0

0

60

33

175

1411

333

407

107

360.7

Counrty / Section Colonies(n) (n)

Breedingpairs (%) per/km

Mean pairs percolonies (n)

*Incl

udin

g Is

land

Bal

ta la

lom

itei,

Grea

t Bra

ila Is

land

and

Sfâ

ntu

Gheo

rghe

bra

nch

The monitoring showed 22,817 breeding pairs at 82 differentcolonies along the whole Danube. Most colonies were foundin the border section of Bulgaria and Romania (between river-km 845 and 374) as well as in the region of the Island of Bal-taIalomitei (river-km 370 to river-km 250), which againhighlights the high value of these areas. When higher plateaubanks are sloped deeply by the Danube, the resulting hugenatural river banks can offer perfect breeding sites; butsmaller natural steep river banks at various places are alsooccupied by Sand Martin.

The largest colonies of Sand Martin were recorded in Serbia,with impressive colony sizes of more than 8,000 breedingpairs in two neighbouring colonies in the “Deliblato sands”Special Nature Reserve. Therefore, this section hosts by farthe highest number of breeding pairs per river-km Danube-wide.

The total lack of this species along the Upper Danube is strik-ing; there is no possibility for breeding directly on the mainstream of the Danube because dynamic lateral erosion – thebasic process initiating steep banks as suitable habitats – hasceased due to damming. Even in the last remaining free-flow-ing section of the Upper Danube, the river is more or less to-tally embanked and doesn´t offer potential breeding sites.

Despite there being more potential habitats between Bu-dapest and Belgrade, only very few colonies were recordedalong the Danube in this section as well. Numerous coloniesin artificial habitats in the hinterland were not counted in thismonitoring.

Very similar to the distribution of the Little Ringed Plover, onlyfew suitable breeding habitats are offered for this species bythe Danube Delta with its huge reed areas and the GreatBraila Island with the banks mostly covered by woods.

Sand Martin colonies (n)35302520151050

2900 2700 2500 2300 2100 1900* 1700 1500 1300 1100 900 700 500 300** 100***

Hydropower dams (n)Breeding sites of Little Ringed Plover (n)

*Including old Danube at Gabcíkovo (>100 km) **Including Parts of branches of Island Balta lalomitei, Great Braila Island (>100 km) *** Sfântu Gheorghe branch (>100 km)

100 kilometer sections

upper Danube middle Danube lower Danube

This monitoring was conducted to learn more from the distri-bution pattern of the indicator species about the Danube-wide status of dynamic river habitats, which are threatenedon a Europe-wide scale. Consequently, the presence and ab-sence of these indicator species illustrates the status of thesehabitats, stressing the need for conservation or restoration.Apart from lower densities of Little Ringed Plover and SandMartin in specific Danube sections for natural reasons (e.g. ingorges, on the Delta), human made hydro-morphological al-terations such as dams, embankments or channelling of theriver are generally identified as the main factors impacting thedistribution of these species. Conversely, important breedingsites demonstrate valuable river sections in terms of dynamicriver habitats. As a result of this monitoring, the Danube Pro-tected Areas have formulated the following demands for thelong-term conservation of Little Ringed Plover and Sand Mar-tin, representative of habitats and hydro-morphologicalprocesses:

1. River dynamics and active morphological processes arevital for the Danube River ecosystem. Consequently, theconstruction of new dams and hydropower plants alongthe Danube is not compatible with the preservation ofriver dynamic habitats and their characteristic coenoses!

2. Permanent relocation of river sediments, arising from riverdynamics combined with intact sediment balances, isneeded to initiate the highly valuable habitats in youngstages of succession. Development and implementationof (hydro-morphological) concepts are needed to ensureand restore the longitudinal continuity of sediment trans-portation along the Danube and its tributaries, and to as-sure the balance in material load per section as well as torestore consequent lateral mobilization of sediments.

3. Breeding sites of Sand Martin are priority subjects of pro-tection! River regulation and embanking needs to beavoided at breeding colonies*, and the inclusion of thesites in Danube Protected Areas has to be intensified toensure long-term conservation, in particular at thehotspots in the Lower Danube.*As most colonies are located at erosion sites of plateaus, conflicts with flood prevention are not expected.

4. Gravel and sand islands are key habitats in the Danubeecosystem! These sites must not be negatively impactedby further river regulation and should consequently be in-cluded in Danube Protected Areas. Their hydro-morpho-logical initiating and obtaining processes Danube-wide,as well as on a local scale, have to be preserved; investi-gations should be done for creation of additional sites.In particular in the Middle and Lower Danube, building upa network of protected islands is seen as a relevant con-tribution.

5. In the Middle Danube, as well as existing colonies, po-tential nesting sites of Sand Martin (all steep natural riverbanks) are also to be strongly taken into consideration forconservation; embanking is to be avoided. Despite numerous Sand Martin colonies in the hinterland,the number of breeding sites on the Danube between Bu-dapest and Belgrade is relatively low and should be pos-itively developed. (Potential) Sand Martin breeding sitesindicate the capacity for natural positive recovery in thissection.

6. The high restoration potential along the last remainingfree-flowing sections of the Upper Danube needs to beused to restore dynamic river habitats!The highest abundance of Little Ringed Plover in some“gravel sections” underlines the potential capacity for thisspecies and its characteristic habitat structures in theUpper Danube, additionally highlighted by the positive im-pact of restoration projects. Removal of embankments isexpected to create potential breeding slopes for SandMartin.

7. In Danube sections altered by dams and hydropowerplants, the (limited) restoration capacity should be usedby specific revitalization actions. Small breeding “populations” of Little Ringed Plovers inthese sections show the potential for revitalization in par-ticular at the beginning of backwaters.

8. The consequent implementation of NATURA 2000 andthe Water Framework Directive, taking stronger river dy-namics and morphological process into consideration, isto be used as a tool for the long-term conservation ofthese species, habitats and initiating processes. The consequent implementation of these demands is along-term investment in the future. In the short term, bothspecies react very quickly to changes in their habitats.Successful examples of river restorations have a positiveinfluence not only on Little Ringed Plover and Sand Martin– transparent representatives for the endangered coeno-sis of these valuable habitats – but on many other plantand animal species and, ultimately, on humans by pro-viding habitats also suitable for recreation. Finally, con-servation and restoration actions for the habitats of LittleRinged Plover and Sand Martin on a Danube-wide scaleoften contribute to ecological flood prevention by givingmore space to the river. Long-term and integrativepreservation of the ecological value of the Danube has toconsider intact river morphology as a basic process ofthe river ecosystem.

Conservation of indicatorspecies and their habitats

INVOLVEMENT OF THE PUBLIC DANUBEPARKS intends to bring more attention toriver morphological processes as a key for natureconservation along the Danube. The adaptation ofLittle Ringed Plover and Sand Martin to their habi-tats makes river dynamics visible and appreciable.Special excursions in Protected Areas, schoolevents on Danube Day, an online video game onthe DANUBEPARKS website, press events andvideo clips produced for the EU Strategy for theDanube Region have accompanied the monitoring.The great interest and positive feedback of stake-holders and the public qualifies the Little RingedPlover and the Sand Martin as drivers for more riverdynamics along the Danube.

Some of the most significan t th rea ts for the habitats of Little Ringed Plover and Sand Martin: riprap embankments, gravel excavation, hydropower dams, inland waterway traffic and human disturbance.

c/o Duna-Ipoly National Park Directorate

1121 Budapest, Költô utca 21., Hungary