Groundwater biodiversity patterns in the Lessinian Massif ... - FaunaItalia

Freshwater Biology (2009) 54, 830–847

doi:10.1111/j.1365-2427.2009.02203.x

Groundwater biodiversity patterns in the Lessinian Massif of northern Italy DIANA M. P. GALASSI, FABIO STOCH, BARBARA FIASCA, TIZIANA DI LORENZO AND ENRICO GATTONE Dipartimento di Scienze Ambientali, University of L’Aquila, Italy

SU M M A R Y 1. The distribution patterns of stygobiotic invertebrates were examined with a stratified sampling design at 197 sites selected among four hydrogeographic basins in the Lessinian Massif (northern Italy). The sites were approximately evenly distributed among four hydrogeological zones: unsaturated and saturated zone of karstic aquifers, and hyporheic and saturated zone of porous aquifers. 2. Outlying Mean Index (OMI) analysis which assesses deviation of habitat conditions from reference conditions, was used to evaluate the importance of 14 selected environmental variables in shaping groundwater biodiversity patterns in the region (total of 89 stygobiotic species). The measured variables explained 80% of the variability in the data set. 3. Sampling sites were distributed along the environmental gradients defined by OMI analysis. Significant differences were detected between karstic and porous site, as well as among sites located in the four hydrogeological zones. Differences among the four hydrogeographic basins were not observed. 4. Ordination of stygobiotic species along the environmental gradients was best explained by historical variables (mainly Wu¨rmian glaciation and age of the underlying geological formation), while variables related to hydrogeology (mainly pH, calcium concentration and habitat fragmentation) influenced species distributions in the hydrogeological zones. An Environmental Integrity Index and nitrate concentration were significantly correlated with altitude, but appeared not to play a significant role in determining stygobiotic biodiversity patterns at the regional scale. 5. Results of the OMI analysis were highly significant for all taxa, suggesting that stygobiotic species are sensitive to the environmental factors studied. Thirty-five species showed high habitat specialization (OMI index > 10). These species were usually rare and endemic to the Lessinian Massif. Most of them were found in a single hydrogeological zone. 6. Quaternary glaciations appear not to have lowered stygobiotic species richness in the Lessinian Massif. This may be because of the marginal location of the region with respect to the Wu¨rmian glacier limit and because of extensive networks of fractures in the vadose zone of the karst, which may have allowed stygobionts to move deep down in the aquifers to seek refuge during surface freezing and to recolonise ancestral habitats after the glaciers retreated. Keywords: biogeography, ecology, ground water, Italy, stygobionts

Correspondence: Diana M. P. Galassi, Dipartimento di Scienze Ambientali, University of L’Aquila, L’Aquila, Italy. E-mail: [email protected]

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Groundwater biodiversity in the Lessinian Massif 831 Introduction Despite great strides in recent years, the true dimension of groundwater biodiversity is largely underestimated and the distribution of groundwater species at various spatial scales remains only sketchily understood (Gibert & Deharveng, 2002; Culver, 2005). This situation stems from the still highly fragmentary knowledge of groundwater biodiversity as a whole, compared to the biodiversity of surface waters, and specifically from the limited number of studies that have analysed the partitioning of groundwater biodiversity at different spatial scales (Gibert et al., 1994a,b, 2000; Ferreira et al., 2005; Dole-Olivier et al., 2009b; Martin et al., 2009). It is widely recognised that both contemporary ecological events and historical contingencies resulting from evolutionary processes shape biodiversity patterns in different environments (Stoch, 1995; Drake et al., 1996; Galassi, 2001; Moritz et al., 2001; Whittaker, Willis & Field, 2001; Gibert & Deharveng, 2002; Moritz, 2002; Colwell, Rahbek & Gotelli, 2004). However, it is far from being understood how these factors interact to control present species diversity and distributions and, consequently, composition of groundwater assemblages. Spatial patterns of biodiversity have mainly been interpreted from an ecological perspective. Only occasionally has the role of historical events been taken into account, and in most of those cases, only narrative explanations have been proposed to elucidate the role of historical factors in determining species diversity and distributions (Rundle et al., 2002; Castellarini et al., 2005; Hahn & Fuchs, 2005; Martin et al., 2005). Approaches that account for both past events and current constraints are complex, however, because of possible interactions among a range of variables, which may obscure the influence of individual factors in shaping species assemblages. This paper examines regional patterns of groundwater biodiversity from both an ecological and historical perspective. Its aims are: (i) to determine the relative importance of various environmental descriptors of species distribution patterns in a region; (ii) to define habitat preferences of groundwater species and characteristic species assemblages along environmental gradients and (iii) to identify the main historical and ecological variables shaping ground 2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847

water biodiversity patterns at different spatial scales within the region.

Methods Study area The study was carried out in the Lessinian Massif, which is one of six European regions chosen for assessing groundwater biodiversity in the PASCALIS project (Gibert, 2001). The region is located in the southernmost part of the Venetian pre-Alps in northern Italy (Fig. 1). The rocky massif of 691 km2 emerged in the Oligocene, 25–24 million years BP (Boccaletti et al., 1990). It extends southward in divergent finger-like ridges that reach the alluvial plain of the River Adige with a mean slope of 10%. The aquifer discharges on average about 50 m3 s)1: 15 m3 s)1 through alluvial deposits, 30 m3 s)1 through stream beds and 5 m3 s)1 through a spring system (Montorio). The ground water flows from north-west to south-east. The main outlets are located along the boundaries of the alluvial plain of the River Adige, where limestone comes in contact with Quaternary alluvial sediments (Patrizi et al., 2001). The hydrological regime of the Lessinian Massif is mostly governed by meteorological events. Infiltrating rainfall tends to flow vertically through the vadose zone of the karstic massif and reaches the deep saturated aquifers in a few hours to a maximum of a few days through an extended network of large and small fractures in the limestone strata. The drainage network consists of tributaries of the River Adige, flowing southward along narrow steep valleys. Streams are often temporary and predominantly fed by rainfall, to a lesser extent by ground water. The geological structure of the massif is dominated by carbonate rocks of Cretaceous and Jurassic ages in the northern part. The basement is represented by a 1000-m deep dolomite stratum, covered by several limestone banks of different origin, reaching a thickness of about 550 m. Eocene limestone is primarily located in the southern part of the massif, while outcrops of volcanic rocks, mainly basaltic, are located in the eastern part. Quaternary alluvial deposits, covering the limestone basement, fill the smaller valleys, as well as the broad Adige plain, where thickness of the alluvial sediments ranges from 100 to 200 m (Patrizi et al., 2001).

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Fig. 1 Map of the Lessinian Massif of northern Italy showing the distribution of sampling sites.

Sampling The stratified sampling approach used in the study area followed the standard protocol of the PASCALIS project, designed to capture most of the environmental heterogeneity at different spatial scales (DoleOlivier et al., 2009a). Four spatial scales were defined: (i) region (Lessinian Massif); (ii) hydrogeographic basin (four basins: Progno di Fumane, 43 km2; Progno di Valpantena, 154 km2; Vaio di Squaranto, 94 km2; Alpone-Tramigna, 137 km2); (iii) aquifer type (karstic and porous) and (iv) hydrogeological zone (unsaturated and saturated zone of karstic aquifers, and hyporheic and saturated zone of porous aquifers). A total of 197 sites were approximately evenly distributed among the four hydrogeological zones in the four basins (Fig. 1). Caves were sampled in the unsaturated (vadose) zone of karstic aquifers (Ku),

springs and wells in the saturated zone of karstic aquifers (Ks), interstitial habitats in the hyporheic zone of porous aquifers (Ph), and wells in the saturated zone of porous aquifers (Ps). Fourteen environmental variables were chosen as environmental descriptors of stygobiotic species distribution in the region and measured at each site: (i) altitude, determined with a geographic positioning system (GPS III Plus; Garmin (Europe) Ltd, Southampton, U.K.) and verified on topographic maps; (ii) temperature; (iii) specific conductivity at 25 C; (iv) dissolved oxygen concentration and (v) pH, measured in the field with a multiparametric probe (ECM Multi; Dr Lange GmbH, Du¨sseldorf, Germany); (vi) calcium concentration, measured by a titrimetric method with EDTA; (vii) magnesium concentration, obtained by difference between total hardness and calcium hardness; (viii) nitrate and (ix) phosphate 2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847

Groundwater biodiversity in the Lessinian Massif 833 concentrations, measured spectrophotometrically (HACH DR 2000; Hach Co., Loveland, CO, U.S.A.) with the cadmium reduction method and the ascorbic acid method, respectively. Five additional environmental variables were determined at each site: (x) distance to the Wu¨rmian glacier border on palaeogeographic maps (Sauro, 1973); (xi) an Environmental Integrity Index according to the CORINE Land Cover classification (CLC; CEC, 1994), available at the web site of the European Environmental Agency (http://www.eea.europa.eu); (xii) age of the underlying geological formation (hereafter called geological age); (xiii) degree of habitat fragmentation and (xix) degree of hydrological isolation from the surface. The Environmental

Integrity Index was developed by first defining the extent of the area of interest, assessed in different ways depending on the hydrogeological features of each sampling site: (i) for springs, the catchment area; (ii) for cave streams, the functional catchment area of the river, and for the vadose habitats, a surface area corresponding to the extension of the underlying karstic vadose zone; (iii) for hyporheic sites, a strip 50m wide along the river banks from the sampling site to the source; (iv) for wells, a circular surface (200 m diameter) around the well. In a second step, the per cent land surface area occupied by the dominant CLC category was assessed. The nominal variables no. xi–xiv were scored according to the criteria described in Table 1.

Table 1 Basic criteria used for the physiographic description of sampling sites in the Lessinian Massif Score Environmental integrity index* 3. Forests and semi-natural areas 3.1. Forests 3.2. Shrub and ⁄ or herbaceous vegetation 2. Agricultural lands 2.3. Pasture 2.4. Heterogeneous agricultural areas 2.1. Arable land 2.2 Permanent crops 1. Artificial surfaces Geological age Jurassic limestone Cretaceous limestone Eocene limestone Quaternary sediments Habitat fragmentation Rimstone pool or trickle Saturated karst Phreatic groundwater in unconsolidated sediments or spring Subterranean river or hyporheic habitat Hydrological isolation from the surface** Porous Thickness of unsaturated zone Recharge by the river >10 m 5–10 m 10)6 10)4 100 m 10–100 m 0.28).

± ± ± ± ± ± ± ± 322 226 470 168 692 225 254 82 50 49 101 96 53 48 48 48

414 259 343 184 297 189 227 39

7.3 7.5 7.4 7.4 7.5 7.2 7.8 6.9

± ± ± ± ± ± ± ±

0.4 0.5 0.4 0.5 0.3 0.4 0.3 0.3

± ± ± ± ± ± ± ±

184 164 173 218 99 150 68 201

± ± ± ± ± ± ± ± 12.2 14.5 12.0 15.3 10.1 14.1 15.2 15.4 494 595 497 621 384 622 463 779

3.1 3.1 3.1 2.9 2.6 2.3 3.2 2.5

4.9 ± 1.4 1.9 ± 0.9 2.3 ± 1.1 2.7 ± 1.2 12.4 ± 8.0 0.12 ± 0.16 23.0 ± 16.5 18 ± 14 60 ± 24 13.4 ± 3.0 391 ± 322 49

7.4 ± 0.4

557 ± 242

7.2 ± 1.7

1.9 ± 0.9 1.7 ± 0.8 2.2 ± 1.1 2.2 ± 1.1 2.8 ± 1.1 3.7 ± 1.1 15.7 ± 9.4 8.8 ± 5.3 0.11 ± 0.20 0.10 ± 0.23 18.8 ± 14.0 18.4 ± 11.4 23 ± 12 23 ± 13 54 ± 23 55 ± 23 6.6 ± 2.1 6.7 ± 1.6 13.6 ± 3.4 14.4 ± 3.4 557 ± 205 586 ± 213 7.4 ± 0.5 7.3 ± 0.4 323 ± 315 353 ± 210 197 49

Geological age Habitat fragmentation Environmental Integrity Index Distance to W€ urmian glacier border ðkmÞ ðmg L1 Þ PO43 ðmg L1 Þ NO3 ðmg L1 Þ Mg2þ Ca2þ ðmg L1 Þ ðmg L1 Þ Dissolved oxygen Temperature ð CÞ ðlS cm1 ; 25 CÞ Specific conductivity pH Altitude ðm a.s.l.Þ No. of sites Spatial scale

Region Progno di Fumane basin Progno di Valpantena basin Vaio di Squaranto basin Alpone–Tramigna basin Karstic aquifers Porous aquifers Unsaturated karst Saturated karst Hyporheic zone Saturated porous aquifers

Hydrological isolation from the surface

Table 2 Summary of environmental variables (mean ± SD) measured at different spatial scales in ground water of the Lessinian Massif

4.9 ± 1.4 4.9 ± 1.4

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2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847

Species richness A total of 89 stygobiotic species were identified in the Lessinian region (Appendix 1). Over one-third of them (35 species) are new to science. Most of these were found for the first time during this survey, but a few were already known from other aquifers in northern Italy (F. Stoch, unpubl. data). Thirty-six species have a distribution apparently restricted to the Lessinian area, i.e. they are strict endemics, and another 23 species appear to be endemic to small karstic or alluvial areas in north-eastern Italy. The highest stygobiotic species richness was found in Copepoda, followed by Oligochaeta and Amphipoda (Table 3). Species richness of the unsaturated karst

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and hyporheic zone was higher than in the saturated zones of karstic and porous aquifers, while the number of species found in the four hydrogeographic basins was similar (Table 3). Distributional rarity was exceedingly high: no stygobionts were found in 29 sites (15% of all sites) and 27 species (30% of all species) occurred in one site only. Even the two most frequently occurring species, the copepods Nitocrella psammophila Chappuis and Speocyclops cf. infernus (Kiefer), were collected in only 27% of the sites.

0.8

(a)

Habitat fragmentation

Ca2+

NO3Altitude

PO43-

Mg2+

Environmental integrity index

–1

1

Distance to glacier T

Oxygen

pH

Species–environment relationships The first two axes of OMI analysis accounted for 80% of the marginality of all taxa. The average marginality of all taxa was highly significant (P < 0.00001; MonteCarlo permutation test on the whole data set), suggesting a strong influence of environmental gradients on the composition of stygobiotic assemblages (Appendix 2). Thirty-nine species (44%) departed significantly from a uniform distribution along the environmental gradient (i.e. they had a statistically significant marginality: P < 0.05; Monte-Carlo permutation test). The high deviations (OMI index > 10) shown by 35 species indicate high habitat specialization. Almost all of these species were found in one of the four hydrogeological zones only, mostly in unsaturated karst or in the hyporheic zone (Fig. 2c). Seventeen of the above 35 species occurred exclusively in the unsaturated zone of the Lessinian karst (Appendix 2). Among the species showing a statistically significant marginality were endemic harpacticoid copepods of the genus Lessinocamptus (L. caoduroi Stoch, L. pivai Stoch) and Parastenocaris (Parastenocaris sp. I1), the endemic bathynellacean Bathynella sp. I1, the endemic isopod Monolistra (Typhlosphaeroma) berica (Fabiani), and the amphipod Niphargus forelii Humbert. Eleven species were recorded exclusively in the hyporheic zone, but only two of them (the ostracod Fabaeformiscandona cf. wegelini Danielopol and the halacaridan Soldanellonyx visurgis Vietz) showed a statistically significant marginality. The number of specialised species found in the saturated zones of porous (six species) and karstic (two species) aquifers was low. Among the most ecologically tolerant species (OMI index < 2) were the gastropod Paladilhliopsis virei (Locard), the amphipod Niphargus longidactylus Ruffo and the cyclopoid copepod Diacyclops italianus

Geological age

Hydrological isolation

Specific conductivity

–0.8 4

(b)

–6

8

–5

3

(c)

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BaLI1

TrI1 RhI1 GiI2 PrI2 DiI4 IgCo NpAq CnI1 MMI1 LeIn NpLe Np2F Np2L NpTa Np2C NpSi DiIt MMSt PlVi MTBe LePi Tr2P

PpIt

Cv2P

Ps2E DiRu MM2C NpTr –3

MeI1 DiI3

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NpBG

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Ph1

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GiI1 CnI2 DiI2 SgLa LoWQ

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Di2C

BaLI2

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CnI3

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PaGe

KoDe

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–3

Fig. 2 (a) Ordination of environmental variables (indicated by arrows) on the space defined by the first two canonical axes extracted by OMI analysis and explaining 80% of the variability in the data set; (b) ordination of sampling sites (black circles = sites in the unsaturated zone of karstic aquifers; grey circles = sites in the saturated zone of karstic aquifers; black triangles = sites in the hyporheic zone of porous aquifers; grey triangles = sites in the saturated zone of porous aquifers); (c) ordination of stygobiotic species (see Appendix 1 for species identification codes).


89 46 42 41 51 75 65 42 33 44 21 Region Progno di Fumane basin Progno di Valpantena basin Vaio di Squaranto basin Alpone–Tramigna basin Karstic aquifers Porous aquifers Unsaturated karstic aquifers Saturated karstic aquifers Hyporheic zone Saturated porous aquifers

12 9 8 7 9 12 16 3 9 9 7

24 9 12 16 14 21 15 12 9 12 3

7 4 2 1 4 5 7 1 4 5 2

2 1 1 1 1 1 1 1 0 0 1

12 7 7 5 7 13 5 9 4 2 3

1 0 0 0 1 0 1 0 0 0 1

6 2 3 2 3 5 3 3 2 0 3

7 5 3 1 2 4 6 1 3 6 0

All taxa Polychaeta Oligochaeta Gastropoda Cyclopoida Harpacticoida Ostracoda Isopoda Amphipoda Thermosbaenacea Bathynellacea Acari Spatial scale

(Kiefer), which are endemic to northern Italy (Appendix 1). The average position of each species along the first axis of the environmental gradient defined by OMI analysis is shown in Fig. 3. The average position of the two most widely distributed species (large-sized circles) are located far away from the origin of the axis, indicating that one of the species (S. cf. infernus) occurred primarily in the vadose zone of karst and, less frequently, in the hyporheic zone, while the other (N. psammophila) mainly occurred in saturated porous sites. The average positions of the two most widely distributed species along the second axis of OMI analysis (Fig. 4) are close to the origin of the axis, indicating wide ecological tolerance to environmental variation. The average positions of the other species are evenly spaced along the altitudinal gradient. Only two species, L. caoduroi and Bathynella (Bathynella) sp. I1, were restricted to high-altitude karstic sites, specifically to the vadose zone of caves located close to the Wu¨rmian glacier border. Both species are endemic to the Lessinian Massif. Two other species, Limnosbaena sp. and Bathynella (Bathynella) sp. I5, are located at the opposite side of the environmental gradient. Both were collected at a single site in a saturated porous aquifer.

Discussion

15 7 4 6 8 10 9 9 1 9 0

2 2 2 2 1 3 2 2 1 1 1

Environmental descriptors

1 0 0 0 1 1 0 1 0 0 0

Species richness

Table 3 Species richness of stygobiotic invertebrate taxa at different spatial scales in ground water of the Lessinian Massif



The groundwater environment in the Lessinian Massif was described by OMI analysis as a gradient from high altitude, unsaturated zones of karstic aquifers, to low altitude saturated karstic and porous zones of more recent geological age and lower environmental integrity. A second gradient, mainly defined by pH and calcium concentration, separated the hyporheic zone from the saturated zones of both karstic and porous aquifers. Nonetheless, a clear distinction between the influence of historical and ecological variables in separating the four hydrogeological zones was partially blurred by a systematic spatial segregation of the hydrogeological zones (arranged in north– south orientation) in the Lessinian region. Unsaturated karstic sites developed in ancient Jurassic and Cretaceous limestone, and are characterised by a high degree of habitat fragmentation, resulting in many microhabitats (Pipan & Culver, 2005; Camacho

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(a) (c)

(b)

Fig. 3 First axis extracted by the OMI analysis of stygobiotic assemblages, which explains 61.7% of the variability in the data set: (a) Environmental variables arranged along the first axis using their canonical weights (environmental gradient); (b) ordination of the 89 stygobiotic species along the first axis using their factorial scores; (c) distribution of species along the environmental gradient as a function of their weighted average position along site scores. Small grey circles represent sites where a species occurs, dark grey circles the centroid (mean position) of a given species along the environmental gradient. Size of the circles is proportional to the total occurrence of a given species. Horizontal bars represent standard deviations. See Appendix 1 for species identification codes.

et al., 2006) with different degrees of isolation (Pipan, Christman & Culver, 2006; Pipan & Culver, 2007). Hyporheic waters were characterised by the lowest calcium concentrations measured in this study. Water flowing through sandy and silty sediments of the hyporheic zones may account for the relatively low calcium concentrations compared to ground water of limestone or gravel aquifers (Bakalowicz, 1994).

Separation of saturated porous and karstic sites along the axes of OMI analysis is less sharp, albeit statistically significant, because both are located at low altitude, in areas with low scores of the Environmental Integrity Index and high nitrate concentrations. Consequently, environmental contrasts among sites in saturated aquifers were low. 2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847


(b)

(a)

(c)

Fig. 4 Second axis extracted by OMI analysis of stygobiotic assemblages, which explains 18.3% of the variability in the data set. See caption of Fig. 3 for details.

Phosphate concentration was not an important environmental factor in the ordination of sites by OMI analysis, and the contribution of NO3) was also weak, albeit statistically significant. This suggests that groundwater pollution by nutrients plays a minor role in defining environmental gradients of groundwater habitats in the region, as was also observed by Hahn 2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847

& Fuchs (2005), Paran et al. (2005), Dole-Olivier et al. (2009b) and Martin et al. (2009).

Habitat preferences of stygobionts The stygobiotic species collected in ground water of the Lessinian Massif showing low tolerance (i.e. a

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high OMI index) were also rare in a geographical sense, showing low frequencies of occurrence, which frequently results in a restricted geographic distribution as well. This is the case for species found almost exclusively in the vadose zone of karst and that are endemic to the Lessinian Massif. Some of these rare species are new to science, such as Bathynella (Bathynella) sp. I1, Bathynella (Lombardobathynella) sp. I2, Parastenocaris sp. I4, Paramorariopsis sp. I1 and three species of the genus Lessinocamptus. Larger stygobiotic species in the region have a wider geographical distribution in the Italian Pre-Alpine or Alpine area, such as the isopod M. (Typhlosphaeroma) berica and the amphipods Niphargus sp. gr. aquilex Schio¨dte, N. lessiniensis Stoch, N. galvagnii Ruffo, and N. forelii Humbert (Ruffo & Stoch, 2006). Some species with restricted ecological tolerance were found exclusively in the hyporheic habitat, e.g. most species of the oligochaete genera Rhyacodrilus and Pristina (new to science and strict endemics to the Lessinian Massif), the ostracod F. cf. wegelini, and several copepod species of the genera Diacyclops and Parastenocaris. Such species often occurred only at a single site. The water mites Kongsbergia dentata Walter, Stygomomonia latipes Szalay and S. visurgis Vietz were mostly found in the same environment, probably because of their strict association with epigean aquatic insects for phoresy (i.e. attachment to other animals for transportation) (Davids et al., 2006). In deep saturated aquifers, most species showed wide ecological tolerance, which is also reflected in their wide geographical distribution [e.g. Elaphoidella elaphoides (Chappuis), N. psammophila, Parapseudoleptomesochra italica Pesce & Petkovski, Niphargus transitivus Sket]. A unique assemblage of ancient marine origin was found at one site. It included two Malacostraca [a Limnosbaena species of the order Thermosbaenacea and the isopod Monolistra (Monolistra) sp. I1], together with an undescribed genus of the harpacticoid family Ectinosomatidae. Local factors may account for this assemblage composition. This fauna may have survived in a very restricted part of the Alpone-Tramigna basin in connate waters, also named fossil aquifers, i.e. confined aquifers in which trapped water has a different age than the geological formation (Fetter, 1994). The most tolerant species, displaying a very low OMI index, had a wide geographical distribution, as

also found by Dole-Olivier et al. (2009b) in a parallel study in the French Jura. The highest tolerance indices were found for (i) the gastropod P. virei, the amphipod N. longidactylus, and the cyclopoid copepod D. italianus, which are restricted to north-eastern Italy (Appendix 1); (ii) the harpacticoid Moraria (Moraria) stankovitchi Chappuis, which is widely distributed in eastern Europe (Petkovski & Brancelj, 1985) and (iii) the cyclopoid Graeteriella (Graeteriella) unisetigera (Graeter), which has a wide geographical range across Europe (Fiers & Ghenne, 2000; Galassi, 2001) and is one of the most common species in the French Jura (Dole-Olivier et al., 2009b) and in the Walloon karst of Belgium (Martin et al., 2009). These species were collected from different groundwater habitats, springs and hyporheic sites (Botosaneanu, 1986). Slight niche shifts among locations together with greater dispersal potential may explain the wide ecological and biogeographical distribution of these tolerant species (indicated by their low OMI index), as observed for some copepod species from both ground water (Galassi, 2001) and surface water (Rundle et al., 2002).

Biodiversity patterns The Lessinian Massif showed a higher stygobiotic species richness (89 species) than all but one of the other European regions investigated in the PASCALIS project with identical methods. Only the Krim Massif in Slovenia had more species, a total of 92 (DoleOlivier et al., 2009a). This high species richness in Lessinian ground water is paralleled by a high number of endemic species, 59 in total, which is equal to as much as 66% of the total species richness. Outlying Mean Index analysis indicates that both historical and ecological variables are influential in determining species diversity patterns in the four hydrogeological zones studied. The historical component, mostly defined by geological age of the aquifer, appears to be important in increasing both total species richness and degree of endemism. This is especially true in the ancient unsaturated karst, where habitats are highly fragmented, thus favouring longterm vicariant events, multiple disjunct refugia and hence speciation. Relatively high species richness was also found in the hyporheic habitat, as also noted by Paran et al. (2005) for a shallow aquifer in France. The richness level of 44 species in the Lessinian Massif is comparable to that found in the unsaturated karst of 2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847

Groundwater biodiversity in the Lessinian Massif 841 the region (42 species). In contrast, the saturated porous and karstic aquifers showed relatively low species richness, probably reflecting low microhabitat diversity and, though less clearly, anthropogenic impacts. Even though the Environmental Integrity Index and nitrate concentration showed statistically significant correlations with altitude in the Lessinian Massif, these variables appear to have played minor roles in explaining stygobiotic biodiversity patterns at the regional scale, as also noted for the French Jura (Dole-Olivier et al., 2009b) and the Walloon karst in Belgium (Martin et al., 2009). This conclusion is tentative, however, since the potential impact of human activities on stygobiotic species richness remains incompletely understood in general (Hancock, 2002; Hancock & Boulton, 2005; Lafont et al., 2006). Separation of stygobiotic assemblages in karstic and porous aquifers and, to a lesser extent, among hydrogeological zones in the French Jura was also found by Castellarini et al. (2005). These authors postulated that differences in physical habitat structure are the major source of variation in species richness and composition between karstic and porous aquifers. Nevertheless, connectivity between basins within the region and distance to the Wu¨rmian glacier limit were important factors accounting for differences in stygobiotic assemblages in their study. This contrasts results obtained by Martin et al. (2009) who failed to find environmental gradients distinguishing karstic and porous aquifers or hydrogeological zones in the Walloon karst of Belgium. The different result of the study of Martin et al.’s (2009), compared to those of both Castellarini et al. (2005) in the French Jura and the present study, could have resulted from strong influences of the Weichselian glaciation on the Walloon karst. Stygobiotic species richness in the Walloon karst is very low (36 species) and most species are habitat generalists with wide geographical distributions, suggesting that aquifers in that region were recolonised after the glaciers retreated (Martin et al., 2009). In the Lessinian ground water, Quaternary glaciations, although important in shaping stygobiotic species distribution, appear not to have strongly affected species richness. Only a few sites in the unsaturated karst were covered by the Wu¨rmian glaciers, and they had high species richness. A similar situation has been observed by Stoch (2000) for the vadose caves of Trentino in northern Italy, by Rouch (1986) for different karstic systems in southern France, and by Holsinger, 2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847

Mort & Recklies (1983) for groundwater systems in Canada, all areas that were ice-covered during the Pleistocene. Plausible explanations of high stygobiotic species richness in the Lessinian Massif caves are their marginal location with respect to the Wu¨rmian glacier limit and the highly fractured nature of the karst. Extensive networks of fractures probably allowed stygobionts to move deep down in the aquifers to seek refuge during surface freezing and to recolonise the ancestral habitats after the glaciers retreated. Results of the present study suggest that the ancient geological age of aquifers in the Lessinian Massif, high habitat fragmentation, and isolation of microhabitats may all have promoted speciation by vicariance, especially in the vadose zone. In particular, the ancient age of the Lessinian karst may have favoured persistence of many endemics, most of which are phylogenetic relicts (i.e. unique remnants of formerly diversified taxonomic groups) or distributional relicts (i.e. taxa with close relatives traceable in disjunct geographical areas) (Holsinger, 1988; Humphreys, 2000). This is the case for the four species of Lessinocamptus, a harpacticoid genus known only from unsaturated karstic sites in eastern Italy (Stoch, 2006), and for some isopod and amphipod species of the genera Monolistra and Niphargus. Conversely, high species richness in the hyporheic habitat may be due to spatial variability in environmental conditions and speciation promoted by niche differentiation (Stoch, 1995; Galassi, Huys & Reid, 2009), as suggested by the co-occurrence of several, closely related species in the same habitat. This scenario could apply to several copepod species of the genera Diacyclops and Parastenocaris.

Acknowledgments We thank Paola D’Ambrosio (L’Aquila), Gianfranco Tomasin (Gorizia) and Enrico Mezzanotte (Verona) who greatly contributed to the sampling. The Adige River Basin Authority (Trento), the ARPA Verona, the Museo Civico di Storia Naturale of Verona and the speleological associations in Verona provided facilities for the field work and hydrogeological maps. A. Camacho (Syncarida), P. Marmonier (Ostracoda), B. Sambugar (Oligochaeta) and A. Di Sabatino (Acari) are greatly acknowledged for species identification. We are also much indebted to J. Gibert, D. Culver and M. Gessner for useful comments on the final draft of

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the manuscript. This study was supported by the PASCALIS project funded by the European Commission (contract no. EVK2-CT-2001-00121).

References Bakalowicz M. (1994) Water geochemistry: water quality and dynamics. In: Groundwater Ecology (Eds J. Gibert, D.L. Danielopol & J.A. Stanford), pp. 97–127. Academic Press, San Diego, CA. Boccaletti M., Ciaranfi N., Cosentino D. et al. (1990) Palinspastic restoration and paleogeographic reconstruction of the peri-Tyrrhenian area during the Neogene. Palaeogeography, Palaeoclimatology, Palaeoecology, 77, 41–50. Botosaneanu L. (1986) Stygofauna Mundi – A Faunistic, Distributional and Ecological Synthesis of the World Fauna Inhabiting Subterranean Waters (Including the Marine Interstitial). E.J. Brill, Leiden. Bou C. & Rouch R. (1967) Un nouveau champ de recherches sur la faune aquatique souterraine. Comptes Rendus de l’Acade´mie des Sciences de Paris, 265, 369–370. Camacho A.I., Valdecasas A.G., Rodrı´guez J., Cuezva S., Lario J. & Sańchez-Moral S. (2006) Habitat constraints in epikarstic waters of an Iberian Peninsula cave system. Annales de Limnologie, 42, 127–140. Castellarini F., Dole-Olivier M.-J., Malard F. & Gibert J. (2005) Improving the assessment of groundwater biodiversity by exploring environmental heterogeneity at a regional scale. In: Proceedings of an International Symposium on World Subterranean Biodiversity (Ed. J. Gibert), pp. 83–88. University Claude Bernard, Lyon. CEC (1994) CORINE Land Cover. Technical Guide. Office for Official Publications of European Communities, Luxembourg. Colwell R.K., Rahbek C. & Gotelli N.J. (2004) The mid-domain effect and species richness patterns: what have we learned so far? The American Naturalist, 163, E1–E23. Culver D.C. (2005) The struggle to measure subterranean biodiversity. In: Proceedings of an International Symposium on World Subterranean Biodiversity (Ed. J. Gibert), pp. 27–28. University Claude Bernard, Lyon. Davids K., Di Sabatino A., Gerecke R., Gledhill T., Smit H. & van der Hammen H. (2006) Acari: Hydrachnidia I. In: Su¨ßwasserfauna von Mitteleuropa, 7 ⁄ 2 – Acari I (Ed. R. Gerecke), pp. 255–340. Spektrum, Heidelberg. Doledec S., Chessel D. & Gimaret-Carpentier C. (2000) Niche separation in community analysis: a new method. Ecology, 81, 2914–2927. Dole-Olivier M.-J., Castellarini F., Coineau N., Galassi D.M.P., Martin P., Mori N., Valdecasas A. & Gibert J.

(2009a) Towards an optimal sampling strategy to assess groundwater biodiversity: comparison across six European regions. Freshwater Biology, 54, 777– 796. Dole-Olivier M.-J., Malard F., Martin D., Lefe´bure T. & Gibert J. (2009b) Relationships between environmental variables and groundwater biodiversity at the regional scale. Freshwater Biology, 54, 797–813. Drake J.A., Hewitt C.L., Huxel G.R. & Kolasa J. (1996) Diversity and higher levels of organization. In: Biodiversity. A Biology of Numbers and Difference (Ed. K.J. Gaston), pp. 149–166. Blackwell Science, Oxford. Ferreira D., Malard F., Dole-Olivier M.-J. & Gibert J. (2005) Hierarchical patterns of obligate groundwater biodiversity in France. In: Proceedings of an International Symposium on World Subterranean Biodiversity (Ed. J. Gibert), pp. 5–78. University Claude Bernard, Lyon. Fetter C.W. (1994) Applied Hydrogeology, 3rd edn. Prentice Hall, Englewoods Cliffs, NJ. Fiers F. & Ghenne V. (2000) Cryptozoic copepods from Belgium: diversity and biogeographic implication. Belgian Journal of Zoology, 130, 11–19. Galassi D.M.P. (2001) Groundwater copepods: diversity patterns over ecological and evolutionary scales. Hydrobiologia, 453 ⁄ 454, 227–253. Galassi D.M.P., Huys R. & Reid J.W. (2009) Diversity, ecology and evolution of groundwater copepods. Freshwater Biology, 54, 691–708. Gibert J. (2001) Protocols for the Assessment and Conservation of Aquatic Life in the Subsurface (PASCALIS): A European Project. Proceedings of ‘‘Mapping Subterranean Biodiversity’’. Special Publication, Karst Water Institute & Laboratoire souterrain de Moulis, Moulis, pp. 19–21. Gibert J. & Deharveng L. (2002) Subterranean ecosystems: a truncated functional biodiversity. BioScience, 52, 473–481. Gibert J., Stanford J.A., Dole-Olivier M.-J. & Ward J.V. (1994a) Basic attributes of groundwater ecosystem and prospects for research. In: Groundwater Ecology (Eds J. Gibert, D.L. Danielopol & J.A. Stanford), pp. 7–40. Academic Press, San Diego, CA. Gibert J., Vervier P., Malard F., Laurent R. & Reygrobellet J.-L. (1994b) Dynamics of communities and ecology of karst ecosystems: example of three karsts in eastern and southern France. In: Groundwater Ecology (Eds J. Gibert, D.L. Danielopol & J.A. Stanford), pp. 425–450. Academic Press, San Diego, CA. Gibert J., Malard F., Turquin M.J. & Laurent R. (2000) Karst ecosystems in the Rhoˆne river basin. In: Ecosystems of the World 30 – Subterranean Ecosystems (Eds H. Wilkens, D.C. Culver & W.F. Humphreys), pp. 533– 558. Elsevier, Amsterdam. 2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847

Groundwater biodiversity in the Lessinian Massif 843 Hahn H.-J. & Fuchs A. (2005) Mapping the stygofauna of the state of Baden-Wu¨rttemberg, southwest Germany. In: Proceedings of an International Symposium on World Subterranean Biodiversity (Ed. J. Gibert), pp. 89–94. University Claude Bernard, Lyon. Hancock P.J. (2002) Human impacts on the stream– groundwater exchange zone. Environmental Management, 29, 763–781. Hancock P.J. & Boulton A.J. (2005) The effects of an environmental flow release on water quality in the hyporheic zone of the Hunter River, Australia. Hydrobiologia, 552, 75–85. Holsinger J.R. (1988) Troglobites: the evolution of cavedwelling organisms. American Scientist, 76, 147–153. Holsinger J.R., Mort J.S. & Recklies A.D. (1983) The subterranean crustacean fauna of Castleguard cave, Columbia Icefields, Alberta, Canada, and its zoogeographic significance. Arctic and Alpine Research, 15, 543–549. Humphreys W.F. (2000) Relict faunas and their derivation. In: Ecosystems of the World, 30. Subterranean Ecosystems (Eds H.D. Wilkens, D.C. Culver & W.F. Humphreys), pp. 417–432. Elsevier, Amsterdam. Lafont M., Vivier A., Nogueira S., Namour P. & Breil P. (2006) Surface and hyporheic oligochaete assemblages in a French suburban stream. Hydrobiologia, 564, 183–193. Malard F., Dole-Olivier M.-J., Mathieu J. & Stoch F. (2002) Sampling Manual for the Assessment of Regional Groundwater Biodiversity. PASCALIS European programme. Available at: http://www.pascalis-project.com. Martin P., De Broyer C., Fiers F., Michel G., Sablon R. & Wouters K. (2005) Biodiversity of Belgian groundwaters: the Meuse basin. In: Proceedings of an International Symposium on World Subterranean Biodiversity (Ed. J. Gibert), pp. 95–98. University Claude Bernard, Lyon. Martin P., De Broyer C., Fiers F., Michel G., Sablon R. & Wouters K. (2009) Biodiversity of Belgian groundwater fauna in relation to environmental conditions. Freshwater Biology, 54, 814–829. Moritz C. (2002) Strategies to protect biological diversity and the evolutionary processes that sustain it. Systematic Biology, 51, 238–254. Moritz C., Richardson K.S., Ferrier S., Monteith G.B., Stanisic J., Williams S.E. & Whiffin T. (2001) Biogeographical concordance and efficiency of taxon indicators for establishing conservation priority in a tropical rainforest biota. Proceedings of the Royal Society of London, Series B, 268, 1875–1881. Paran F., Malard F., Mathieu J., Lafont M., Galassi D.M.P. & Marmonier P. (2005) Distribution of groundwater invertebrates along an environmental gradient in a shallow 2009 Blackwell Publishing Ltd, Freshwater Biology, 54, 830–847

water-table aquifer. In: World Subterranean Biodiversity, Proceedings of an International Symposium (Ed. J. Gibert), pp. 99–105. University Claude Bernard, Lyon. Patrizi G., Lavagnoli M., Zuppi G. et al. (2001) Indagine idrogeologica, geochimica e geochimico-isotopica sugli acquiferi della Lessinia. Settore Ecologia, Provincia di Verona, Verona. Petkovski T.K. & Brancelj A. (1985) Zur Copepodenfauna (Crustacea) der Grotten Skocjanske Jame in Slowenien. Acta Musei Macedonici Scientiarum Naturalium, 18, 1–25. Pipan T. & Culver D.C. (2005) Estimating biodiversity in the epikarstic zone of a West Virginia cave. Journal of Cave and Karst Studies, 67, 103–109. Pipan T. & Culver D.C. (2007) Copepod distribution as an indicator of epikarst system connectivity. Hydrogeology Journal, 15, 817–822. Pipan T., Christman M.C. & Culver D.C. (2006) Dynamics of epikarstic communities: microgeographic pattern and environmental determinants of epikarstic copepods in Organ Cave, West Virginia. American Midland Naturalist, 156, 75–87. Rouch R. (1986) Copepoda: les Harpacticoı¨des souterrains des eaux douces continentales. In: Stygofauna Mundi – A Faunistic, Distributional and Ecological Synthesis of the World Fauna Inhabiting Subterranean Waters (Including the Marine Interstitial) (Ed. L. Botosaneanu), pp. 321–355. E.J. Brill, Leiden. Ruffo S. & Stoch F. (2006) Crustacea Malacostraca Amphipoda. In: Checklist and Distribution of the Italian Fauna (Eds S. Ruffo & F. Stoch), pp. 109–111. Memorie del Museo civico di Storia naturale di Verona, Sezione Scienze della Vita, Verona. Rundle S., Bilton D., Galassi D.M.P. & Shiozawa D. (2002) The geographical ecology of freshwater meiofauna. In: Freshwater Meiofauna: Biology and Ecology (Eds S.D. Rundle, A.L. Robertson & J.M. Schmid-Araya), pp. 279–294. Backhuys Publishers, Leiden. Sauro U. (1973) Il paesaggio degli alti Lessini. Studio geomorfologico. Memorie del Museo civico di Storia naturale di Verona, fuori serie, 6, 1–161. Stoch F. (1995) The ecological and historical determinants of crustacean diversity in groundwaters, or: why are there so many species? Me´moires de Biospeólogie, 22, 139–160. Stoch F. (2000) Indagini sulla fauna acquatica delle grotte del Trentino (Italia Settentrionale). Studi Trentini di Scienze Naturali, Acta Biologica, 74, 117–132. Stoch F. (2006) Crustacea Copepoda Cyclopoida. In: Checklist and Distribution of the Italian Fauna (Eds S. Ruffo & F. Stoch), pp. 117–132. Memorie del Museo civico di Storia naturale di Verona, Sezione Scienze della Vita, Verona.

844


Thioulouse J., Dole´dec S., Chessel D. & Olivier J.-M. (1997) ADE-4: a multivariate analysis and graphical display software. Statistics and Computing, 7, 75–83. Whittaker R.J., Willis K.J. & Field R. (2001) Scale and species richness: towards a general, hierarchical

theory of species diversity. Journal of Biogeography, 28, 453–470. (Manuscript accepted 11 February 2009)

Appendix 1 List of stygobiotic species collected from ground water in the Lessinian Massif. Two asterisks (**) indicate species strictly endemic to the Lessinian Massif; one asterisk (*) indicates species endemic to larger areas of north-eastern Italy Taxonomic group

Endemism

Polychaeta Oligochaeta ** **

* ** ** ** * ** ** ** Gastropoda Cyclopoida

* * *

* * * * **

Harpacticoida

* ** ** **

* * ** ** ** ** ** * *

Species

Identification Code

Troglochaetus beranecki Delachaux Cernosvitoviella cf. parviseta Gadzinska Gianius sp. I1 Gianius sp. I2 Gianius cf. labouichensis (Rodriguez & Giani) Haber sp. Parvidrilus spelaeus Martıńez-Ansemil, Sambugar & Giani Phallodrilinae indet. Pristina sp. I1 Pristina sp. I2 Pristina sp. I3 Rhyacodrilus cf. dolcei Martıńez-Ansemil, Sambugar & Giani, Rhyacodrilus sp. I1 Rhyacodrilus sp. I2 Trichodrilus sp. I1 Trichodrilus cf. pragensis Vejdovsky Iglica concii (Allegretti) Paladilhiopsis virei (Locard) Diacyclops cf. maggii Pesce & Galassi Diacyclops cf. clandestinus (Kiefer) Diacyclops italianus (Kiefer) Diacyclops paolae Pesce & Galassi Diacyclops ruffoi Kiefer Diacyclops sp. I1 Diacyclops sp. I2 Diacyclops sp. I3 Diacyclops sp. I4 Graeteriella (Graeteriella) unisetigera (Graeter) Speocyclops cf. infernus (Kiefer) Speocyclops sp. I1 Bryocamptus sp. I1 Ceuthonectes serbicus Chappuis Ectinosomatidae gen. I1 sp. I1 Elaphoidella elaphoides (Chappuis) Elaphoidella phreatica (Chappuis) Elaphoidella pseudophreatica (Chappuis) Elaphoidella sp. I1 pivai Lessinocamptus caoduroi Stoch Lessinocamptus insoletus (Chappuis) Lessinocamptus pivai Stoch Lessinocamptus sp. I1 Lessinocamptus sp. I2 Moraria (Moraria) sp. I1 Moraria (Moraria) stankovitchi Chappuis Nitocrella psammophila Chappuis

TroB Cv2P GiI1 GiI2 Gi2L Ha1 PvSp Ph1 PrI1 PrI2 PrI3 Rh2D RhI1 RhI2 TrI1 Tr2P IgCo PlVi Di2M Di2C DiIt DiPa DiRu DiI1 DiI2 DiI3 DiI4 GrUn Sp2I SpI1 BrI1 CeSe EcI1 ElEl ElPh ElPs ElI1 LeCa LeIn LePi LeI1 LeI2 MMI1 MMSt NiPs


Groundwater biodiversity in the Lessinian Massif 845 Appendix 1 (Continued) Taxonomic group

Endemism

** ** *

Ostracoda

Isopoda Amphipoda

** ** ** ** ** ** ** **

* ** * * **

* ** ** * * * * Thermosbaenacea Bathynellacea ** ** ** ** ** Acari

Species

Identification Code

Parapseudoleptomesochra italica Pesce & Petkovski Paramorariopsis sp. I1 Paramorariopsis sp. I2 Parastenocaris gertrudae Kiefer Parastenocaris italica Chappuis Parastenocaris sp. I1 Parastenocaris sp. I2 Parastenocaris sp. I3 Parastenocaris sp. I4 Candoninae gen. I2 sp. I1 Candoninae gen. I2 sp. I2 Candoninae gen. I1 sp. I1 Candoninae gen. I1 sp. I2 Cavernocypris subterranea (Wolf) Fabaeformiscandona cf. wegelini Danielopol Pseudocandona cf. eremita (Vejdovsky) Monolistra (Typhlosphaeroma) berica (Fabiani) Monolistra (Monolistra) sp. I1 Niphargus sp. gr. aquilex Schio¨dte Niphargus bajuvaricus grandii Ruffo Niphargus cf. costozzae Schellenberg Niphargus forelii Humbert Niphargus cf. forelii Humbert Niphargus galvagnii Ruffo Niphargus lessiniensis Stoch Niphargus cf. lessiniensis Stoch Niphargus longidactylus Ruffo Niphargus similis G. Karaman & Ruffo Niphargus tamaninii Ruffo Niphargus transitivus Sket Limnosbaena sp. Bathynella sp. Bathynella (Bathynella) sp. I1 Bathynella (Bathynella) sp. I5 Bathynella (Lombardobathynella) sp. I1 Bathynella (Lombardobathynella) sp. I2 Meridiobathynella sp. I1 Stygomomonia latipes Szalay Kongsbergia dentata Walter Kongsbergia sp. Lobohalacarus weberi quadriporus (Walter) Soldanellonyx visurgis Vietz Soldanellonyx chappuisi Walter Halacarellus phreaticus Petrova

PpIt PmI1 PmI2 PaGe PaIt PaI1 PaI2 PaI3 PaI4 CnI1 CnI2 CnI3 CnI4 CaSu Fa2W Ps2E MTBe MM2C NpAq NpBG Np2C NpFor Np2F NpGa NpLe Np2L NpLo NpSi NpTa NpTr Th1 Ba1 BaBI1 BaBI5 BaLI1 BaLI2 MeI1 SgLa KoDe Ko1 LoWQ SoVi SoCh HaPh


846


Appendix 2 Results of the OMI analysis based on OMI index and its variance terms. OMI = Outlying Mean Index (marginality); T = tolerance (outlying variance); RT = residual tolerance; P = probability value (significance of the OMI index assessed using Monte-Carlo permutation test). Species are arranged in decreasing order of marginality. Species with a statistically significant marginality are shown in bold. N = total number of sites where a taxon occurred. The relative occurrence of species (%) is given within the four hydrogeological zones: Ku = unsaturated (vadose) zone of karstic aquifers; Ks = saturated zone of karstic aquifers; Ph = hyporheic zone of porous aquifers; Ps = saturated zone of porous aquifers) Species

OMI

T

RT

P

N

Ku

Ks

Ph

Ps

Bathynella (Bathynella) sp. I1 Lessinocamptus caoduroi Limnosbaena sp. Bathynella (Lombardobathynella) sp. I2 Bathynella (Bathynella) sp. I5 Elaphoidella phreatica Pristina sp. I3 Bathynella sp. Parastenocaris sp. I4 Troglochaetus beranecki Niphargus forelii Fabaeformiscandona cf. wegelini Pristina sp. I2 Niphargus galvagnii Bryocamptus sp. I1 Speocyclops sp. I1 Gianius sp. I2 Soldanellonyx visurgis Gianius cf. labouichensis Monolistra (Monolistra) sp. I1 Lessinocamptus sp. I1 Parastenocaris sp. I2 Niphargus transitivus Bathynella (Lombardobathynella) sp. I1 Elaphoidella elaphoides Candoninae gen. I1 sp. I2 Lessinocamptus pivai Rhyacodrilus sp. I1 Parapseudoleptomesochra italica Kongsbergia dentata Cavernocypris subterranea Monolistra (Typhlosphaeroma) berica Niphargus sp. gr. aquilex Paramorariopsis sp. I1 Trichodrilus sp. I1 Moraria (Moraria) sp. I1 Diacyclops ruffoi Elaphoidella pseudophreatica Paramorariopsis sp. I2 Parastenocaris italica Parastenocaris gertrudae Niphargus cf. forelii Niphargus similis Parastenocaris sp. I1 Halacarellus phreaticus Rhyacodrilus cf. dolcei Rhyacodrilus sp. I2 Trichodrilus cf. pragensis

38.6 38.6 25.9 22.6 21.6 20.9 20.3 19.8 18.2 17.3 17.1 15.9 15.5 15.3 14.5 12.6 12.4 12.3 11.9 11.9 11.8 11.7 11.6 11.5 11.3 11.1 11.0 10.8 10.5 10.3 10.2 10.2 10.1 10.0 10.0 9.7 9.5 9.5 9.5 9.4 9.2 8.4 8.3 7.9 7.9 7.9 7.9 7.7

»0 »0 0 »0 0 0 »0 1.1 2.3 »0 »0 0.1 0 »0 »0 »0 0 »0 0 0.3 0 0.1 »0 0.3 »0 0 0.9 »0 0.2 »0 »0 0.7 0.2 0.1 »0 1.7 1.4 0.6 0 1.1 0.1 0 1.9 0.1 0.4 0 0 0.7

1.0 1.0 0 1.0 0 0 1.0 5.8 2.4 1.0 3.8 1.1 0 1.0 1.0 1.0 0 3.2 0 3.1 0 0.7 1.0 3.4 1.0 0 15.9 1.0 2.9 0.8 2.5 2.5 2.2 2.0 1.0 5.3 8.9 3.2 2.0 3.9 3.4 0 6.6 4.5 2.2 0 0 3.7

0.030 0.030 0.054 0.076 0.092 0.119 0.124 0.020 0.027 0.212 0.001 0.013 0.276 0.306 0.316 0.415 0.379 0.027 0.411 0.090 0.447 0.040 0.474 0.108 0.494 0.521