TAXONOMIC DIVERSITY of CRUSTACEA CYCLOPOIDA in the AUSTRIAN ”DANUBE FLOODPLAIN” NATIONAL PARK Dan Danielopol, Peter Pospisil

TAXONOMIC DIVERSITY OF CRUSTACEA CYCLOPOIDA IN THE AUSTRIAN ”DANUBE FLOODPLAIN” NATIONAL PARK Dan Danielopol, Peter Pospisil

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Dan Danielopol, Peter Pospisil. TAXONOMIC DIVERSITY OF CRUSTACEA CYCLOPOIDA IN THE AUSTRIAN ”DANUBE FLOODPLAIN” NATIONAL PARK. Vie et Milieu / Life & Environ- ment, Observatoire Océanologique - Laboratoire Arago, 2002, pp.67-75. hal-03198735

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TAXONOMIC DIVERSITY OF CRUSTACEA CYCLOPOIDA IN THE AUSTRIAN "DANUBE FLOODPLAIN" NATIONAL PARK

DAN L. DANIELOPOL* PETER POSPISIL** *Institute of Limnology, Austrian Academy of Sciences, Mondseestr. 9, 5310 Mondsee, Austria ** Reichmanngasse 3/6, 1160 Vienna, Austria

CRUSTACEA. CYCLOPOIDA ABSTRACT. - The groundwater dwelling cyclopoid assemblages of the "Danube HOTSPOT DIVERSITY SITE Floodplain" National Park are more taxonomically diverse than earlier known for TAXONOMIC DIVERSITY the régional cyclopoid fauna. Comparative studies on subsurface assemblages of two approximate 0.8 Km2 areas in the National Park, the "Untere Lobau" and the "Regelsbrunner Au", show that the former site displays a higher taxonomic diversity than the latter, le., higher values for the average taxonomic distinctness index (AvTD) and for the number of gênera with reduced number of species (G1/2 type). The conspicuous taxonomic diversity of the subsurface cyclopoids which exist in the "Untere Lobau" supports the characterization of this area as a hotspot of diversity. The hypogean fractions of cyclopoid assemblages of both the "Untere Lobau" and the "Regelsbrunner Au" areas display lower average taxonomic distinctness values than those of the entire assemblages from which they originate and higher va- riances of their taxonomic distinctness (VarTD). The species rich and taxonomically diverse cyclopoid fauna in the National Park confirm the high ecological and cultural value of this landscape and its importance with respect to Aus- trian interests in environmental protection of the natural héritage of the Danube.

CRUSTACEA, CYCLOPOIDA RÉSUMÉ. - Les Cyclopoïdes peuplant le Parc National « Prairies du Danube » ont SITES À DIVERSITÉ EXCEPTIONNELLE une diversité taxonomique importante par rapport à la faune régionale totale. DIVERSITÉ TAXONOMIQUE L'étude comparative des communautés peuplant deux sites, "Untere Lobau" et "Re- gelsbrunner Au", d'une surface d'environ 0,8 Km2 chacun, dans le Parc National, montre que le premier présente une diversité taxonomique importante: il se dis- tingue par des valeurs élevées de l'index de la distinction taxonomique moyenne (average taxonomic distinctness - AvTD) ainsi que par le nombre des genres ayant un nombre réduit d'espèces (le type G1/2). Le "Untere Lobau" est un site à diversité exceptionnelle (hotspot diversity site) tenant compte de la diversité taxonomique importante des Cyclopoïdes recensés dans les eaux souterraines de ce périmètre. La fraction hypogée des assemblages des Cyclopoïdes des deux sites, "Untere Lobau" et "Regelsbrunner Au", présentent des valeurs plus faibles pour l'indice de la distinction taxonomique moyenne et des valeurs plus importantes de la variance de la distinction taxonomique (Variance of taxonomic distinctness - VarTD), par rapport à celles de la communauté d'origine. La faune des Cyclopoïdes de ce Parc National, ayant une diversité taxonomique exceptionnelle, confirme l'intérêt écologique et culturel porté en Autriche pour la conservation de cette région naturelle du Danube.

INTRODUCTION of various assemblages occurring in subsurface aquatic habitats. Taxonomic diversity can be characterised in several ways, e.g., through the exami- The présent contribution examines the diversity nation of the distribution of taxa in an assemblage of Cyclopoida, a microcrustacean group which within a Linnaean classification system, or just by counting the number of taxa belonging to a given commonly occurs in the alluvial plain of the Dan- hierarchical level (e.g. number of species, of gên- ube at Vienna and down this city in the "Danube era etc). Another approach is to use indices of di- Floodplain" National Park. In addition to species versity calculated from the présence/absence of richness, our aim is to compare the taxonomic di- taxa (i.e., the average and variation of the taxo- versity of both epigean and hypogean dwelling taxa 68 DANIELOPOL DL, POSPISIL P nomic distinctness of assemblages using the algo- nean fauna plays a secondary rôle for décisions in rithms of Clarke & Warwick 1998, 2001). The in- environmental policies. To avoid such an interpré- formation provided by the évaluation of the tation when evaluating the diversity of cave fauna taxonomic diversity enables the characterization of in the world, Culver & Sket (2000) proposed a sim- hotspot diversity sites (Danielopol et al. 2002). ple rule of thumb in order to characterise hotspot diversity sites Le'., a minimum of 20 stygobitic spe- Analysis of the cyclopoid fauna of the "Danube cies per cave site. Floodplain" National Park addresses the following Rouch & Danielopol (1997) and Danielopol et questions: al. (2000a) suggested that the aquatic subterranean (1) Is the taxonomic diversity of animal assem- fauna when examined in toto, Le., both the blages inhabiting subsurface areas higher or lower hypogean and the epigean fractions, could be more than those of epigean assemblages from the same diverse than commonly accepted. This impression area? (2) Can we characterise a hotspot diversity émerges from various investigations, including site using taxonomical diversity of Cyclopoida? ours, e.g., Lescher Moutoué (1973), Stoch (1987, This status for the subsurface part of the "Untere 2001) , Holsinger (1993), Reid (1993, 2001), Lobau," an important part of the "Danube Steenken (1998), Humphreys (1999), Strayer & Floodplain" National Park, was proposed by Reid (1999), Sket (1999b), Danielopol et al. (1999, Danielopol & Pospsisil (2001) using the entire list 2002) , Dumas & Lescher-Moutoué (2001), Galassi of stygobitic fauna of this area and by Danielopol (2001). In order to better evaluate the diversity of et al. (2002) using the taxonomic diversity of crus- the world's subterranean fauna, several teams of tacean Harpacticoida. (3) Which ecological factors specialists are involved in projects which aim to play a rôle in the réalisation of the observed map taxonomic distributions at local, régional and cyclopoid diversity of the "Danube Floodplain" continental scales, e.g., Gibert (2001), Stoch National Park? (4) Of what benefit is information (2001), Christman & Culver (2001). The présent on the taxonomic diversity of subterranean study should be understood as a contribution to this cyclopoids to the environmental planners and/or to international effort. the administration of the "Danube Floodplain" Na- tional Park?

Answers to thèse questions are needed because MATERIAL AND METHODS it was stressed that the diversity of stygobites ex- pressed as species richness within local or régional areas is, in many cases, lower than the diversity of Sampling sites: The "Danube Floodplain" National the epigean fauna (Marmonier et al. 1993, Sket Park is a natural reserve of about 9300 hectares along 1999a). When integrated within the gênerai discus- the alluvial plain of the river. It is located in Vienna and sion on the value of faunal protection, this latter east of Vienna and continues down to the Slovakian bor- opinion could give the impression that subterra- der (Fig. 1). The landscape of the park is remarkable

j 10 km

SLOVAKIA

Fischamend

Danube Floodplain National Park "Regelsbrunner Au" \ Scharndorf i The Danube

Fig. I. - The "Danube Floodplain" National Park, with the location of the "Untere Lobau" and the "Regelsbrunner Au' areas and the U-Lobau ecosystems A, B and C (from Betriebsgesellschaft Marchfeldkanal 1994, modified) TAXONOMIC DIVERSITY OF CYCLOPOIDA 69 through the diversity of terrestrial and aquatic ecosys- The cyclopoid fauna: The cyclopoid data presented tems with a huge number of animal and végétal species here stem from long-term investigations in two areas of (Manzano 2000). The park's landscape is also highly ap- the "Danube Floodplain" National Park: the "Untere Lo- preciated for its tourist value and also it has been the ob- bau" and the "Regelsbrunner Au" (Fig. 1). We used pu- ject of various scientific research for many years, e.g., blished data (Danielopol 1983, Pospisil 1994a, 1994b, Lôffler (1976), Danielopol (1983), Danielopol et al. 1999a, Danielopol et al. 1999a, 2001, Pospisil & Danie- (2000b), Pospisil (1994a), Schiemer (1995), Tockner et lopol 2000, Danielopol & Pospisil 2001) as well as un- al. (1999, 2000). published information with the kind permission of several students from the Limnological Department, The "Untere Lobau" is an area along the Danube allu- University of Vienna: G Pfaffenwimmer (doctoral thesis vial plain of about 10 Km length (Fig 1). The surface 1986), T Hein, A Steininger and I Wenzl (sampling pro- water Systems are largely disconnected from the main tocols and material offered to taxonomic identification). channel of the Danube river. The subsurface of the allu- The subterranean cyclopoid fauna sampled in the "Re- vial plain in this area forms a large aquifer which is dy- gelsbrunner Au" by I Wenzl and A Steininger were iden- namically connected to the régional Marchfeld aquifer at tified by one of us (PP) and presented in Pospisil & the northern part and to the Danube river at the Danielopol (2000). south-eastern part (Danielopol et al., 2000b, 2001). In order to better characterise the régional diversity Groundwater ecological investigations were carried out of the cyclopoid fauna occurring in Lower Austria at three sites of the "Untere Lobau" (U-Lobau A, B, C, around the "Danube Floodplain" National Park, we also Fig. 1) within a perimeter of about 0.8 Km2. The sur- used information existing in Humpesch & Moog (1994), face-water habitats of an old arm of the Danube, the Gaviria (1998a, 1998b), Schônbauer (1999), Tockner et Eberschùttwasser have also been included in various stu- al. (2000), Baranyi et al. (2002). dies (Danielopol 1983, Pfaffenwimmer 1986, Pospisil 1999a). This backwater of the Danube connects the subsurface sites U-Lobau A and C (Danielopol 1983, Pospi- Analytical methods: The taxonomic diversity of the sil 1994b, Danielopol et al. 1997, 2000b, 2001). Epigean cyclopoid assemblages were characterised with différent fauna of the Eberschùttwasser infiltrâtes into the sur- descriptors following the protocols used in Rouch & Da- rounding groundwater habitats (see below). nielopol (1997) and (Danielopol et al. 2002): (1) the taxonomic list of the assemblage, including three levels The U-Lobau A site is an area of submerged alluvial 2 of the Linnaean hierarchy: the species, the genus and the sédiment area of about 30 m with a high permeability subfamily; (2) the species richness, the number of epi- and a high rate of water infiltration; as an ecosystem it gean and hypogean taxa; (3) the higher-taxon richness, was thoroughly described by Danielopol (1983, 1989, represented by the number of gênera with few and with 1991). The U-Lobau B is a large area of about 0.6 Km2 many species, the so-called G1/2 and G3 taxa (Danielopol located between the Eberschùttwasser and the Danube et al. 2002); (4) the average of taxonomic distinctness (for précise location and description see Pospisil 1994a, (AvTD = Delta+) and the variation of taxonomic distinc- 1994b, 1999a and Danielopol et al. 2001). As an ecosys- tness (VarTD = A +) as described by Clarke & Warwick tem, U-Lobau B displays the classic characteristics of (1998, 1999, 2001). Thèse two latter indices are espe- the deep groundwater Systems, Le., a very slow water cially well suited for the characterisation of the taxono- velocity and low fluctuations of the température during mic diversity of groundwater dwelling crustaceans the year; the fauna at this site mainly consists of exclusi- (Danielopol et al. 2002) because they are independent of vely hypogean dwelling animais, and it is seldom floo- sampling effort, thus allowing comparisons between pré- ded by the Danube high waters. Finally, the U-Lobau C sent/absent species in the assemblages (Warwick & site displays characteristics intermediate of the other two Clarke 2001). Moreover we will compare the taxonomic Lobau sites. The water from Eberschùttwasser generally distinctness of a local assemblage with those of the total infiltrâtes into the aquifer, which has a surface area of 2 species list of a régional assemblage following the ran- about 900 m , and when the Danube and associated domisation test and the 95% probability funnel method backwaters expérience elevated discharge, this site is of Clarke & Warwick (1998) using 5000 random sélec- completely flooded. The subsurface fauna at the U-Lo- tions from the master list of 38 species. This procédure bau C site is composed of a mixture of epigean and hy- allowed us to verify if the observed data départ signifi- pogean animais with a prédominance of epigean forms cantly from sub-samples with an équivalent number of (Danielopol et al. 1992, 1994, 1997, 2000b). species extracted randomly from the total (régional) spe- The "Regelsbrunner Au" is a small floodplain (about cies list. 10 Km long) located about 25 Km east of Vienna The values of the indices for taxonomic distinctness (Fig. 1). The side arms were largely isolated from the (AvTD and VarTD) as well as the Clarke & Warwick Danube river but the hydrologie régime is much more randomisation test were computed with the computer active than those of the Lobau area previously discussed, package PRIMER-5 (Plymouth Routines in Multivariate especially during the high water levels of the river Ecologie Research) for Windows, version 5.2 (Clarke & (Schiemer et al. 1999, Tockner et al. 1999, 2000). The Gorley 2001). sample sites used for groundwater research lay within a transect which crosses an area of about 0.8 Km2. Three sites were chosen, each with piezometers located at 2-3 depths between 3 and 7 m deep. Two of the sites lay RESULTS closely to the side arms while the third one is located outside the backwaters. Groundwater fauna was sampled every two months during 1994/1995 (leg I Wenzl) and The number of cyclopoid species in the National 1997 (leg A Steininger). Park at the two sites, the "Untere Lobau" and the 70 DANIELOPOL DL, POSPISIL P

Table I. - The taxonomic list of the Cyclopoida sampled in the "Danube Floodplain" National Park, the "Untere Lo- bau" (U-Lobau) and the "Regelsbrunner Au" areas: SI - U-Lobau A; S2 - U-Lobau B; S3 - U-Lobau C; S4 - Regels- brunner Au; S5 - Eberschùttwasser; SI - S4, subsurface habitats, S5, surface benthic habitat; SI, S5 - cyclopoids det. by G Pfaffenwimmer and P Pospisil; S2 - S4, cyclopoids det. P Pospisil; EC - Ecological characterisation; Hy - Hypo- gean (= stygobitic) taxon; Ep - Epigean taxon; Cy - Cyclopoida. * Species identified by G Pfaffenwimmer in Danielo- pol 1983.

No. EC TAXA SI S2 S3 S4 S5 Fam. Cyclopidae Sars S-Fam. Eucyclopinae Kiefer 1 Hy Austriocyclops vindobonae Kiefer - + - - - 2 Ep Eucyclops serrulatus (Fischer) + - + - + 3 Ep Eucyclops speratus (Lilljeborg) - - - + - 4 Hy Eucyclops graeteri Kiefer - + - + - 5 Ep Eucyclops sp. + - - - - 6 Ep Macrocyclops albidus (lutine) - - + - + 7 Ep Macrocyclops fuscus (Jurine) - - - - + 8 Ep Paracyclops fimbriatus (Fischer) + - - - - 9 Ep Paracyclops sp. + - - S-Fam. Cyclopinae (Dana) Kiefer 10 Ep Cyclops vicinus Fischer - - - - + 11 Ep Cyclops strenuus Fischer - - - - + 12 Ep Cyclops sp. - - + - - 13 Hy Acanthocyclops rhenanus Kiefer* + - - - - 14 Hy Acanthocyclops gmeineri Pospisil - + - + - 15 Hy Acanthocyclops kieferi (Chappuis) - - - + - 16 Ep Acanthocyclops vernalis (Fischer) + - + - + 17 Hy Acanthocyclops venustus ssp.(Norman & Scott) + + + + - 18 Hy Acanthocyclops sensitivus (Graeter & Chappuis) + + + + - 19 Ep Acanthocyclops viridls (Jurine) - - + - - 20 Ep Acanthocyclops robustus (Sars) + - + + + 21 Ep Acanthocyclops sp. + - - - - 22 Hy Diacyclops cohabitatus Monchenko - + - + - 23 Ep Diacyclops bicuspidatus (Claus) + + + - + 24 Hy Diacyclops danielopoli Pospisil & Stoch - + - + - 25 Ep Diacyclops disjunctus (Thallwitz) - - + - - 26 Ep Diacyclops languidoides (Lilljeborg) + - - - - 27 Hy Diacyclops felix Pospisil & Stoch + + + + - 28 Ep Diacyclops languidus (Sars) + - + - + 29 Ep Cryptocyclops bicolor (Sars) - - + - + 30 Hy Graeteriella unisetigera (Graeter) - - + - - 31 Ep Thermocyclops crassus (Fischer) - - - - 32 Ep Thermocyclops oithonoides (Sars) - - + + + 33 Ep Thermocyclops sp. + - - - + 34 Ep Megacyclops viridis (Haller) - - - - + 35 Ep Mesocyclops leuckarti (Claus) + - + - + 36 Ep Metacyclops planus (Gurney) - - + - - 37 Ep Microcyclops varicans (Sars) - - + - - 38 Ep Microcyclops rubellus (Lilljeborg) - - - - + Total Cy Species / Site 16 9 18 11 16 Total Hy Species / Site 4 8 4 8 0

"Regelsbrunner Au" is 38 (Table I), of which four Lobau" area (Tables III, S1-S3, U-Lobau A+B+C) species were left in open nomenclature. Ail thèse we identified 30 species, of which 10 are species belong to the family Cyclopidae Sars and stygobites). The sites "Regelsbrunner Au" (S4) and are distributed within two subfamilies, the U-Lobau B (S2) display lower species richness (11 subfamily Eucyclopinae Kiefer, represented by and 9 species respectively, of which 8 are 9 species, and the subfamily Cyclopinae (Dana) stygobites). The total number of G1/2 and G3 gênera Kiefer, with 29 species. There are 27 epigean and within the two areas we investigated (Table II) is 11 stygobitic species. high (9 and 5, respectively) whereas, the number of

G1/2 and G3 gênera (Table II) of most of the Lobau Of the five sites we investigated (Table I), the and Regelsbrunn wetland subsurface sites, is re- most species rich is the site U-Lobau C with duced (2-4 Gm, respectively 1 - 2 G3 gênera per 18 species (14 epigean and 4 hypogean taxa), fol- site). This resuit was obtained from analyses in- lowed by the surface water habitats of the back- cluding both epigean and hypogean gênera, and water Eberschùttwasser (16 epigean species) and also from analyses of sytgobitic gênera only. The the subsurface site U-Lobau A (12 epigean and backwater Eberschùttwasser (S5) and the 4 hypogean species). In the 0.8 Km2 "Untere subsurface U-Lobau C site (S3) have a high num- TAXONOMIC DIVERSITY OF CYCLOPOIDA 71

Table IL - Diversity of Cyclopoida within the "Danube Floodplain" National Park; G1/2 - genus with 1 or 2 species; G3 - genus with 3 or more species; AvTD - Average taxonomic distinctness; VarTD - Variation of taxonomic distinctness; Hy - stygobitic fraction of taxa (additional explanations in text and Table I).

Sites within the Assemblage Species Hypogean Genus Genus G3 AvTD VarTD No. Danube area Code Richness Species Qfn (No.) (No.) (No.) (No.) 0 "Danube Floodplain" DFP 38 11 9 5 75.63 446 National Park 1 Eberschùttwasser E 16 0 9 1 75.56 346.9 2 U-Lobau/A+B+C LABC 30 10 10 3 74.87 481.9 3 U-Lobau/A+B+C-Hy LABCHy 10 10 3 2 71.85 590 4 U-Lobau/A LA 16 4 4 2 73.61 609.2 5 U-Lobau B LB 9 8 2 2 71.3 688.4 6 U-Lobau/B-Hy LBHy 8 8 2 2 73.81 663.3 7 U-Lobau/C LC 18 4 9 2 70.15 336.4 8 Regelsbrunner Au R 11 8 2 2 69.09 640.6 9 Regelsbrunner Au-Hy RHy 8 8 1 2 64.29 629.3

ber of G1/2 gênera (9) and a low number of G3 gên- 90r era (1-2), while the entire subsurface Lobau area (U-Lobau/A+B+C, Table II) is characterised by

10 G1/2 gênera and only 3 G3 gênera. The two cumulated areas we investigated had the highest value of average taxonomic diversity (75.63) in the National Park (Table II). The AvTD value was high for the epigean assemblage of the backwater Eberschùttwasser (75.56), while the values for the subsurface assemblages are lower, i.e., U-Lobau/ A+B+C area, 74.87, the U-Lobau A site, Number of species 73.61 and the site U-Lobau B, 71.3. The AvTD values for the stygobitic fractions of the U-Lobau B Fig.2. - Average taxonomic distinctness values (Delta+) and the U-Lobau/A+B+C lay in between the previ- for nine cyclopoid assemblages from the "Danube Flood- ous data (73.81 and 71.85). The AvTD values are plain" National Park, plotted against the observed num- even lower for the subsurface cyclopoid fauna of ber of species for the total list of the "Untere Lobau" and the "Regelsbrunner Au" area: 69.09 for the entire the "Regelsbrunner Au" areas (DFP). Dashed line, the simulated mean; thin line, the 95% probability funnel for assemblage and only 64.29 for the exclusively the expected range of Delta+ values constructed from hypogean fraction. random sublists of species. Assemblage codes as in The variations in taxonomic distinctness (Ta- Table II. ble II) were low (between 336.4 and 481.9) for assemblages or species collections from both surface and subsurface areas which had a high number of (2000a, 2000b) the number of recorded cyclopoid Gm gênera (9-10) i.e., those of the Eberschùttwasser, the U-Lobau A+B+C and the U-Lobau/C assem- species in Austria is 54; they belong to one family, blages. High values (between 590 and 688.4) were the Cyclopidae, and are classified in 18 gênera and observed for those assemblages with low number 2 sub-families. The cyclopoid fauna recorded in the "Danube Floodplain" National Park is formed by of G i/2 gênera (1-3), i.e., the assemblages of the "Regelsbrunner Au", of the U-Lobau A and the the 34 species discussed here and three species, hypogean fractions of the U-Lobau/A+B+C and Ectocyclops phaleratus (Koch), Diacyclops U-Lobau/B. crassicaudis (Sars) and Diacyclops bisetosus (Rehberg), mentioned by Gaviria (1998a) as occur- The AvTD values for the 9 assemblages investi- ring in the Lobau but de facto sampled outside this gated (Table II) lay inside the 95% confidence fun- area by one of us (PP), at Eckartsau. The number of nel (Fig. 2) calculated from the total species list of cyclopoid species occurring in the "Danube Table I. Floodplain" National Park (without the four species left in open nomenclature) represents 68% of the présent known Austrian fauna. The species DISCUSSION richness of the régional cyclopoid fauna of the Danube area within the Vienna Basin is 44 (Kiefer 1964, Gaviria 1998a, 1998b, Schônbauer 1999, From the information published by Gaviria Pospisil & Danielopol 2000), hence only few (1998a), Pospisil & Stoch (1999), Stoch & Pospisil species were not yet recorded in the "Danube 72 DANIELOPOL DL, POSPISIL P

Floodplain" National Park like the stygobitic mation of the site's unusually rich diversity, evalu- cyclopoid Paragraeteriella sp., known from the ated with other animal groups (Danielopol & deeper part of the Marchfeld aquifer (Pospisil & Pospisil 2001, Danielopol et al. 2002). The taxo- Danielopol 2000), Cyclops insignis Claus found in nomic diversity of the subsurface cyclopoid fauna the Danube River, at Freudenau (Schônbauer of the Lobau is comparable with those of another 1999), Paracyclops poppei (Rehberg) sampled in hotspot diversity area, the System Postojna-Planina the new built Marchfeld Canal (Gaviria 1998b), cave System, where Brancelj (1987) mentioned Megacyclops gigas Claus, Paracyclops affinis 24 cyclopoid species (6 stygobites) belonging to

(Sars), Eucyclops macrurus (Sars), E. macruroides 11 gênera (8 G1/2, 3 G3 taxa) and two subfamilies. (Lilljeborg) observed in the "Alte Donau" in Vi- The stygobitic fraction of the cyclopoid assem- enna (Gaviria 1998a). The taxonomic diversity ex- blages of the "Untere Lobau" and the pressed as number of gênera, in the area investi- "Regelsbrunner Au" areas, with lower taxonomic gated by us, represents 87.5% of the régional diversity values than those of the entire assemblage generic taxa. from which they originate, confirm the opinions of When characterised by the AvTD index the taxo- Marmonier et al. (1993) and Sket (1999a) men- nomic diversities of subsurface cyclopoid assem- tioned above (cf. Introduction), that the faunas blages fall within the 95% probability funnel for dominated by stygobitic taxa are less diverse than the simulated distribution of this index suggesting the epigean assemblages. that within the National Park there are no signifi- The taxonomic diversity values of subsurface cant statistical différences between the taxonomic diversity of epigean and hypogean cyclopoid as- dwelling cyclopoid assemblages of the two semblages as compared to the régional cyclopoid investigated areas, the "Untere Lobau" and the diversity. One should also note the position of the "Regelsbrunner Au", are in our opinion related to the structure and functioning of the landscape eco- U-Lobau/A+B+C assemblage within the funnel, as systems to whom they belong. The "Untere Lobau" compared to the other subsurface assemblages, i.e., it has the highest AvTD value (comparable with area is characterised by surface aquatic Systems (e.g., the Eberschùttwasser) which do not dépend those of the Eberschùttwasser) and the highest number of species. strongly on the hydrological dynamics of the Dan- ube river (Schiemer 1999, Tockner et al. 2000, The high values of the VarTD for the hypogean Pospisil 1999a, Danielopol et al. 2000b, 2001). fractions of cyclopoid assemblages reflects an in- teresting characteristic of their taxonomic diver- The aquatic landscape in the Danube wetlands of sity, i.e., the contrasting stygobitic lineages: on one the National Park is formed by a mosaic of ecosys- side the speciose G gênera Acanthocyclops, and tems, tightly interconnected. One notices the strong 3 connectivity between the epigean Eberschùttwasser Diacyclops on the other side, the existence of lin- System with the subsurface U-Lobau ecosystems eages with rare species which belong to Gm gên- era. The protection of thèse latter lineages against (especially the A and C ones) as described in extinction is especially imperative. This situation Danielopol et al. 1997, 2000b, 2001). This explains should be compared with that of the surface the high number of epigean species which colo- cyclopoid fauna of the backwater Eberschùttwasser nises the subsurface habitats of this area. In con- which has a more even taxonomic distribution and, trast, the dynamics of the U-Lobau B System, hence, was assigned a lower VarTD value. This site which is mainly recharged by the Danube river is much slower than those of the U-Lobau A and C has a high number of G gênera with generalist 1/2 ecosystems (Danielopol et al. 2000b, 2001). The species, for which spécial protection measures are not required. number of epigean species which could be intro- duced from the Danube river is low; it reflects the The cyclopoid assemblage of the Eberschùttwasser gênerai low diversity of the cyclopoid fauna in the has a higher species richness and generic taxo- main channel of the river. For instance, for the nomic diversity in comparison to those recorded in whole Austrian sector Humpesch & Moog (1994) the impounded sectors of the Danube river. In the could mention only 12 species belonging to eight

Freudenau area 11 species belonging to six gênera gênera (7 G1/2 1 G3 taxa) and two subfamilies. (4 Qj/2 and 2 G3 taxa) and 2 subfamilies were identified (Schônbauer 1999), while in the Altenwôrth The aquatic system of the "Regelsbruner Au" area is much more strongly dépendent on the hy- impoundment 10 species, belonging to eight G1/2 gênera and two subfamilies were sampled (A drological dynamics of the Danube (Schiemer et al. Herzig, pers comm to DLD). 1999, Ward et al. 1999, Tockner et al. 2000, Schiemer 2001). The cyclopoid fauna of the Because of its subsurface cyclopoid fauna with epigean aquatic Systems is less diverse than that of high species richness, high taxonomic diversity and the Eberschùttwasser. During the one year sam- high number of stygobitic species, the "Untere pling program, when the subsurface cyclopoids Lobau" area should be considered a hotspot diver- mentioned here were sampled (A Steininger sity site. This décision confïrms the previous esti- unpubl.), only six species belonging to fïve GI/2 TAXONOMIC DIVERSITY OF CYCLOPOIDA 73 gênera were recorded in the surface backwaters (for similar arguments see also Danielopol 1989, (Tockner et al. 2000, T Hein, pers comm to DLD). Pospisil & Danielopol 1990, Marmonier et al. Increased connectivity between the Danube river 1997, Danielopol & Pospisil 2001). and the Regelsbrunner-floodplain area leads to strong flushing effects of the epigean cyclopoid fauna during high water levels (Baranyi et al. 2002). Hence the magnitude of the epigean fraction CONCLUSIONS which are able to colonise the aquatic subsurface habitats in the Regelsbrunner area is reduced. Ad- ditionally, because gravel sédiments become 1. The "Danube Floodplain" National Park has a densely packed in this area and/or soft sédiment ac- very species rich and taxonomically diverse cumulâtes, the infiltration of surface water into the cyclopoid fauna, when compared to the régional Regelsbrunner aquifer along the side arms is proba- cyclopoid fauna or to the entire Austrian records. bly more reduced than at the sites U-Lobau A and 2. The taxonomic diversity values of subsurface C. Therefore the taxonomic diversity of the former dwelling cyclopoid assemblages differ from site to area is lower because of the few epigean cyclopoid site depending on the position of thèse sites within species and a higher number of hypogean taxa be- the landscape ecosystems. longing to few gênera. In this way the cyclopoid 3. Some of subsurface cyclopoid assemblages dis- fauna of the "Regelsbrunner Au" more closely re- play values of taxonomic diversities similar to sembles the assemblage of the U-Lobau B than the those of surface-water Systems. other Lobau cyclopoid assemblages. 4. The hypogean fractions of species rich The aim of the "Danube Floodplain" National cyclopoid assemblages display lower taxonomic di- Park is to protect one of the most diverse areas of versity values than those of the entire assemblage Central Europe; about 700 species of plants and from which they originate. over 300 animal species exist (Manzano 2000, 5. The "Untere Lobau" area we investigated, tak- ing in considération the subsurface cyclopoid fauna Tockner et al. 2000). Considérations of aquatic animal diversity, often emphasize fishes rather than with its high species richness, high taxonomic di- invertebrate fauna (Schiemer & Waidbacher 1992, versity and high number of stygobitic species, Schiemer 1999, Ward et al. 1999, Tockner et al. should be considered a hotspot diversity site. 2000). Our study of cyclopoid crustaceans présents 6. The species rich and taxonomically diverse data supporting their inclusion as a focal group on cyclopoid fauna documented in the "Danube faunal diversity lists; they are very well suited to Floodplain" National Park are good arguments for characterise locations of high diversity. further protecting this unique natural landscape and for further funding projects dealing with ground- Besides ensuring environmental protection, the water ecology topics. administrators of this National Park should recog- ACKNOWLEDGEMENTS. - We are much indebted to the nise the existence of rare species in the Danube colleagues who offered information and help during the wetland landscape which have to be better ecologi- préparation of this study: A Baltanâs (Madrid), J Dreher, cally studied in order to be protected. Pospisil & S Gaviria, T Hein, F Schiemer, A Steininger, I Wenzl Danielopol (1990) proposed that the administration (ail in Vienna), KR Clarke (Plymouth), N Coineau of the Danube National Park include groundwater (Banyuls/Mer), A Herzig (Ilmitz), F Lescher-Moutoué ecology subject matter in their scientific programs. (Paris), B Lahnsteiner (Mondsee), P Marmonier (Ren- This aim was partly fulfilled through a séries of nes), J Reid (Martinsville, Virginia), Olyssa Starry long-term ecological projects done by various in- (Blacksburg, Virginia), F Stoch (Trieste) and the autho- terdisciplinary research groups in both the "Untere rities of the "Danube Floodplain" National Park, G Hau- Lobau" and the "Regelsbrunner Au" areas (cf. Ma- benberger, A Placho, R Schreckeneder, H Tomsic and C Baumgartner. We are grateful for the financial support terial & Methods section). Here we want to point received during the years from the Austrian "Fonds zur out that future scientific activities should also in- Fôrderung der wissenschaflichen Forschung" Projects clude ecological studies on rare stygobitic No. P7881 and PI 1149. cyclopoid species like Austriocyclops vindobonae, Graeteriella unisetigera, Acanthocyclops sensitivus, Acanthocyclops gmeineri, Diacyclops disjunctus,

Diacyclops cohahitatus etc, species that were diffi- REFERENCES cult to locate and further to sample outside the Na- tional Park (Pospisil & Stoch 1997, Pospisil 1989, 1999b, Stoch & Pospisil 2000a, 2000b, Pospsil & Baranyi C, Hein, Holarek C, Kekeis S, Schiemer F 2002. Danielopol 2000, Danielopol et al. 2001). Such ac- Zooplankton biomass and community structure in a tivities are not only of scientific interest but also Danube River floodplain System: effects of hydrolo- represent a cultural contribution in that ecological gy. Freshwater Biol 47: 1-10. information ean further be disseminated to citizens Betriebsgesellschaft Marchfeldkanal 1994. Konzept fur interested in the maintenance of nature's splendour den Nationalpark Donau-Auen., Betriebsgesellschaft 74 DANIELOPOL DL, POSPISIL P

Marchfeldkanal, Deutsch-Wagram (Unpubl Report), Danielopol DL, Pospisil P, Dreher J, Môsslacher F, Tor- 15p. reiter P, Geiger-Kaiser M, Gunatilaka A 2000b. A Brancelj A 1987. Cyclopoida and Calanoida (Crustacea, groundwater ecosystem in the wetlands of the Danube Copepoda) from the Postojna-Planina Cave System at Vienna (Austria). In Caves and other subterranean (Slovenia). Biol Vestn 35: 1-16. ecosystems, Ecosystems of the World, 30, H Wilkens, Christman MC, Culver DC 2001. Spatial models for pre- D Culver, W Humphreys Eds, Elsevier, Amsterdam: dicting cave biodiversity: an example from southeas- 487-517. tern United States. In Mapping subterranean Danielopol DL, Rouch R, Baltanâs A 2002. Taxonomic biodiversity, DC Culver, L Deharveng, J Gibert, ID diversity of groundwater Harpacticoida (Copepoda, Sasowsky Eds, Karst Waters Institute Spécial Publ 6: Crustacea) in southern France; a contribution to cha- 36-38. racterise Hotspot diversity Sites. Vie Milieu 52: 1-15. Clarke KR, Gorley RN 2001. PRIMER v5, User ma- Danielopol DL, Rouch R, Bou C 1999. High Amphipoda nual/tutorial. Primer-E, Plymouth, 91p. species richness in the Nert groundwater System (sou- Clarke KR, Warwick RM 1998. A taxonomic distinc- thern France). Crustaceana 72: 883-892. tness index and its statistical properties. J Appl Ecol Danielopol DL, Rouch R, Pospisil P, Torreiter P, 35: 523-531. Môsslacher F 1997. Ecotonal animal assemblages; Clarke KR, Warwick RM 1999. The taxonomic distinc- their interest for groundwater studies. In Groundwa- tness measure of biodiversity: weighting step lengths ter/Surface Water Ecotones, J Gibert, J Mathieu, F between hierarchical levels. Mar Ecol Prog Ser 184: Fournier Eds, Cambridge Univ. Press, Cambridge: 21-29. 11-20. Clarke KR, Warwick RM 2001. A further biodiversity Dreher J, Pospisil P, Danielopol DL 1997. The rôle of index applicable to species lists: variation in taxono- hydrology in defïning a groundwater ecosystem. In mic distinctness. Mar Ecol Prog Ser 216: 265-278. Groundwater/Surface Water Ecotones, J Gibert, J Ma- thieu, F Fournier Eds, Cambridge Univ. Press, Cam- Culver DC, Sket B 2000. Hotspots of subterranean bio- bridge: 119-126. diversity in caves and wells. J Cave Karst Studies 62: 11-17. Dumas P, Lescher-Moutoué F 2001. Cyclopoid distribution in an agriculturally impacted alluvial aquifer. Danielopol DL 1983. Der EinfluC organischer Arch Hydrobiol 150: 511-528. Verschmutzung auf das Grundwasser-Ôkosystem der Donau im Raum Wien und Niederôsterreich. Bundes- Galassi DMP 2001. Groundwater copepods: diversity ministerium fur Gesundheit und Umweltschutz Fors- patterns over ecological and evolutionary scales. Hy- chungsberichte 5/83: 5-160. drobiologia 453/454: 227-253. Danielopol DL 1989. Groundwater fauna associated Gaviria S 1998a. Checklist of the free-living copepods with riverine aquifers. J Amer Benthol Soc 8: 18-35. (Arthropoda: Crustacea) from Austria. Ann Naturhist Mus Wien 100B: 539-594. Danielopol DL 1991. Spatial distribution and dispersai of interstitial Crustacea in alluvial sédiments of a Gaviria S 1998b. Colonization of a new man-made river backwater of the Danube at Vienna. Stygologia 6: (MarchfeldKanal, Lower Austria) by benthic cope- 97-110. pods. J Marine Syst 15: 127-134. Danielopol DL, Creuzé des Châtelliers M, Moesslacher Gibert J 2001. Protocols for the assessment and conser- F, Pospisil P, Popa R 1994. Adaptation of Crustacea vation of aquatic life in the subsurface (PASCALIS): to interstitial habitats: A practical agenda for ecologi- an European project. In Mapping subterranean biodi- cal studies. In Groundwater Ecology, J Gibert, DL versity, DC Culver, L Deharveng, J Gibert, I.D Sa- Danielopol, JA Stanford Eds, Académie Press, San sowsky Eds, Karst Waters Institute Spécial Publ 6: Diego: 217-243. 19-21. Danielopol DL, Dreher J, Gunatilaka A, Kaiser M, Nie- Holsinger JR 1993. Biodiversity of subterranean amphi- derreiter R, Pospisil P, Creuzé des Châtelliers M, pod crustaceans: global patterns and zoogeographic Richter A 1992. Ecology of organisms living in a hy- implications. J Nat Hist 27: 821-835. poxic groundwater environment at Vienna (Austria); Humpesch UH, Moog O 1994. Flora und Fauna der methodological questions and preliminary results. In ôsterreichischen Donau. In Biologie der Donau, W J Simons, J Stanford Eds, Proc lst Int Conf Kinzelbach Ed, G Fischer Verlg, Stutgart: 81-107. Ground-Water Ecology, US EPA, AWRA, Washing- Humphreys WF 1999. Relict stygofaunas living in sea ton DC: 79-90. sait, karst and calcrete habitats in arid northwestern Danielopol DL, Pospisil P 2001. Hidden biodiversity in Australia contain many ancient lineages. In The other the groundwater of the Danube Flood Plain National 99%; the conservation and biodiversity of invertebra- Park (Austria). Biodiv Conserv 10: 1711-1721. tes, W Ponder, D Luney Eds, Trans Roy Zool Soc Danielopol DL, Pospisil P, Dreher J 2001. Structure and NSW: 219-227. functioning of groundwater ecosystems in a Danube Kiefer F 1964. Zur Kenntnis der subterranen Copepoden wetland at Vienna. In Groundwater ecology; a tool (Crustacea) Ôsterreichs. Ann Naturhist Mus Wien 67: for management of water resources, C Griebler, DL 477-485. Danielopol, J Gibert, HP Nachtnebel, J Notenboom Lescher-Moutoué F 1973. Sur la biologie et l'écologie Eds, Office for Officiai Publications of the European des Copépodes Cyclopides hypogés (Crustacés). Ann Communities, Luxembourg: 121-141. Spéléol 28: 581-674. Danielopol DL, Pospisil P, Rouch R 2000a. Biodiversity Lôffler H 1976. Limnologie Lobau, Kurzfristprogramm, in groundwater, a large-scale view. TREE 15: Limnolgisches Institut ÔAW, Wien (Unpubl Report), 223-224. 80p. TAXONOMIC DIVERSITY OF CYCLOPOIDA 75

Manzano C 2000. GroBrâumiger Schutz von Feuchtge- Schiemer F 2001. Limnological research in the Danube bieten im Nationalpark Donau-Auen. Stapfia 69: wetlands with emphasis on environmental manage- 229-248. ment and restoration scénarios. In Groundwater eco- Marmonier P, Vervier Ph, Gibert J, Dole-Olivier M-J logy; a tool for management of water resources, C 1993. Biodiversity in groundwaters. TREE 8: Griebler, DL Danielopol, J Gibert, HP Nachtnebel, J 392-395. Notenboom Eds, Office for Officiai Publications of Marmonier P, Ward JV, Danielopol DL 1997. Biodiver- the European Communities, Luxembourg: 289-305. sity in groundwater/surface water ecotones: central Schiemer F, Baumgartner C, Tockner K 1999. Restora- quuestions. In Groundwater/Surface Water Ecotones, tion of floodplain rivers, the Danube Restoration Pro- J Gibert, J Mathieu F Fournier Eds, Cambridge Univ. ject. Regul Rivers: Res Mgmt 15: 231-244. Press, Cambridge: 231-235. Schiemer F, Waidbacher H 1992. Stratégies for conser- Pfaffenwimmer G 1986. Zur Limnologie einiger aus- vation of the Danubian fish fauna. In River conserva- gewahlter Lobau-Altwasser. Doct Thesis, Univ Wien, tion and management, PJ Boon, P Calow, GE Petts 207p. Eds, J Wiley, Chichester: 364-384. Pospisil P 1989. Acanthocyclops gmeineri n.sp. (Crusta- Schônbauer B 1999. Spatio-temporal patterns of macro- cea, Copepoda) aus dem Grundwasser von Wien benthic invertebrates in a free-flowing section of the (Osterreich): Bemerkungen zur Zoogeographie und River Danube in Austria. Arch Hydrobiol Suppl zur Sauerstoffsituation des Grundwassers am Fun- 115/3: 375-397. dort. Zool Anz 223: 220-230. Sket B 1999a. The nature of biodiversity in hypogean waters and how it is endangered. Biodiv Conserv 8: Pospisil P 1994a. Die Grundwassercyclopiden (Crusta- 1319-1338. cea, Copepoda) der Lobau in Wien (Ôsterreich)-fau- nistische, taxonomische und ôkologische Sket B 1999b. High biodiversity in hypogean waters and Untersuchungen. Doct Thesis, Univ Wien, 222p. its endangerment-the situation in Slovenia, the Dina- ric Karst and Europe. Crustaceana 72: 767-780. Pospisil P 1994b. The groundwater fauna of a Danube Steenken B 1998. Die Grundwasserfauna. Ein Vergleich aquifer in the Lobau Wetland in Vienna, Austria. In zweier Grundwasserlandschaften in Baden-Wurttem- Groundwater Ecology, J Gibert, DL Danielopol, JA berg. Ecomed, Landsberg, 160p. Stanford Eds, Académie Press, San Diego: 317-366. Stoch F 1987. I cyclopoidi (Crustacea, Copepoda) délie Pospisil P 1999a. The composition of cyclopoid assem- acque interne ad est del F Piave: considerazioni faunis- blages in ecologically différent groundwater habitats tiche e biogeografiche. Biogeographia 13: 539-551. of a Danube riverine wetland in Austria. Crustaceana Stoch F 2001. How many species of Diacyclops! New 72: 883-892. taxonomic characters and species richness in a fresh- Pospisil P 1999b. Acanthocyclops sensitivus (Graeter & water cyclopid genus (Copepoda, Cyclopoida). Hy- Chappuis, 1914) (Copepoda: Cyclopoida) in Austria. drobiologia 453/454: 525-531. Annls Limnol 35: 49-55. Stoch F, Pospisil P 2000a. Redescription of Diacyclops Pospisil P, Danielopol DL 1990. Vorschlage fur den disjunctus (Thallwitz, 1927) from Austria, with re- Schutz der Grundwasserfauna im geplanten National- marks on the Diacyclops languidus-gxoup in Europe park "Donauauen" ôstlich von Wien, Osterreich. Sty- (Copepoda, Cyclopoida, Cyclopidae). Crustaceana gologia 5: 75-85. 73: 469-478. Pospisil P, Danielopol DL 2000. Diversity of groundwa- Stoch F, Pospisil P 2000b. The Diacyclops languidoi- ter dwelling Cyclopoida (Crustacea, Copepoda) in a cfes-group (Copepoda: Cyclopoida) in Austria, with Danube wetland in Austria. Vie Milieu 50: 137-150. redescription of Diacyclops cohabitatus Monchenko, Pospisil P, Stoch F 1997. Rediscovery and redescription 1980. Annls Limnol 36: 21-29. of Austriocyclops vindobonae Kiefer, 1964 (Copepo- Strayer DL, Reid JW 1999. Distribution of hyporheic cy- da, Cyclopoida) with remarks on the subfamily Eucy- clopoids (Crustacea, copepoda) in the eastern United clopinae Kiefer. Crustaceana 70: 901-910. States. Arch Hydrobiol 145: 79-92. Pospisil P, Stoch F 1999. Two new species of the Diacy- Tockner K, Baumgartner C, Schiemer F, Ward JV 2000. clops languidoides-group (Copepoda, Cyclopoida) from Biodiversity of a Danubian floodplain: structural, groundwaters of Austria. Hydrobiologia 412: 165-176. functional and compositional aspects. In Biodiversity Reid JW 1993. The harpacticoid and cyclopoid copepod in wetlands: assessment, function and conservation, B fauna in the Cerrado région of central Brazil. 1. Spe- Gopal, WJ Junk, JA Davis Eds, Backhuys Publ, Lei- cies composition, habitats and zoogeography. Acta den, 1: 141-159. Limnol Brasiliensia 6: 56-68. Tockner K, Schiemer F, Baumgartner C, Kum G, Wei- Reid JW 2001. A human challenge: discovering and un- gand E, Zweimûller I, Ward JV 1999. The Danube derstanding continental copepod habitats. Hydrobio- Restoration Project, species diversity patterns across logia 453/454: 201-226. conectivity gradients in the floodplain System. Regul Rouch R, Danielopol DL 1997. Species richness of mi- Rivers: Res Mgmt 15: 245-258. crocrustacea in subterranean freshwater habitats. Ward JV, Tockner K, Schiemer F 1999. Biodiversity of Comparative analysis and approximate évaluation. Int floodpain river ecosystems, ecotones and connectivi- Rev ges Hydrobiol 82: 121-145. ty. Regul Rivers: Res Mgmt 15: 125-139. Schiemer F 1995. RevitalisierungsmaBnahmen fur Au- Warwick RM, Clarke KR 2001. Practical measures of gewâsser - Môglichkeiten und Grenzen. Arch Hydro- marine biodiversity based on relatedness of species. biol Suppl. 101: 163-178. Oceanogr Mar Biol Ann Rev 39: 207-231. Schiemer F 1999. Conservation of biodiversity in flood- Reçu le Ier mars 2002; received March I, 2002 plain rivers. Arch Hydrobiol Suppl 115/3: 423-438. Accepté le 4 avril 2002; acceptedApril 4, 2002