The Impact of Environmental Factors on Diversity of Ostracoda in Freshwater Habitats of Subarctic and Temperate Europe

Ann. Zool. Fennici 49: 193–218 ISSN 0003-455X (print), ISSN 1797-2450 (online) Helsinki 31 August 2012 © Finnish Zoological and Botanical Publishing Board 2012

The impact of environmental factors on diversity of Ostracoda in freshwater habitats of subarctic and temperate Europe

Anna Iglikowska1,2 & Tadeusz Namiotko2

1) Institute of Oceanology, Polish Academy of Sciences, Department of Marine Ecology, ul. Powstańców Warszawy 55, PL-81-712 Sopot, Poland (corresponding author’s e-mail: iglikowska@ iopan.gda.pl) 2) Laboratory of Limnozoology, Department of Genetics, University of Gdańsk, ul. Kładki 24, PL-80-822 Gdańsk, Poland

Received 3 Aug. 2011, final version received 15 Feb. 2012, accepted 22 Mar. 2012

Iglikowska, A. & Namiotko, T. 2012: The impact of environmental factors on diversity of Ostracoda in freshwater habitats of subarctic and temperate Europe. — Ann. Zool. Fennici 49: 193–218.

In this study, we compared the ostracod species diversity in selected inland-water habi- tats of Lapland and Poland, and assessed the relationships between ostracod occur- rence and abiotic environmental variables. In total, 41 species were collected, of which only 15 species were found in Lapland, as compared with 35 in Poland. Almost all spe- cies collected from the Lapland sites were eurybiontic and no clear differences were found between ostracod assemblages inhabiting different habitat types. We hypoth- esize that this homogeneity might be a consequence of the raised water level during the springtime snow melt, temporarily connecting various waterbodies. The main factors limiting distribution of ostracod species in Lapland appeared to be low pH and low ionic content of water. In Poland, predominantly stenobiontic species were observed. In temporary waters and peat-bogs of this area useful indicator species were identified.

Introduction tens et al. 2008), but even within Europe there are areas where the ostracod fauna has been Ostracods are tiny ubiquitous arthropods, occur- less well explored, as e.g. northern Fennoscan- ring in all marine and non-marine aquatic habi- dia (Iglikowska & Namiotko 2010). The Polish tats, and are even found in some terrestrial ostracod fauna is faunistically better known, habitats such as humid forest soils (Horne et al. but our knowledge of ecology and relationships 2002). Nowadays, there are about 8000 ostra- with environment is still inadequate, with only cod species globally, of which slightly more a single paper published on this topic to date (by than 2000 are freshwater species belonging to Martins et al. 2009). three superfamilies: Darwinuloidea, Cypridoidea Ostracods are used as indicators of particular and Cytheroidea (Martens et al. 2008). In the characteristics of aquatic habitats: many species whole Palaearctic, the region with the highest have different, specific tolerance ranges and pref- ostracod specific diversity, there are 87 known erences within the full spectrum of environmen- genera with about 700 freshwater species (Mar- tal factors (see e.g. reviews in Holmes & Chivas 194 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49

2002, Park & Smith 2003). The development masses warmed by the northward flow of the of multivariate methods in ecology in the last North Atlantic Drift (Gulfstream). This amelio- decades of the 20th century has helped to reveal rating influence is countered by the strong cool- species–environment relationships. In Europe, ing effect of arctic and continental air masses recent papers using such methods have reported from Eurasia. The Scandinavian Mountains play on relationships between freshwater ostracods a major role in shaping climate of the Fennos- and environmental factors in France (e.g. Mar- candia by blocking the warm Atlantic air masses monier et al. 2000), Germany (e.g. Viehberg (Tikkanen 2005). Annual air temperature range 2006), Hungary (Kiss 2007), Italy (e.g. Pieri et is about 10 °C along the west coast of Norway, al. 2009), Luxembourg (Gerecke et al. 2005), but it is a more extreme (29 °C) in the Finnmark Poland (Martins et al. 2009), Portugal (Martins region (to the east of the Scandinavian Moun- et al. 2010), Serbia (Karan-Žnidaršič & Petrov, tains) and 26–28 °C in NE Finland. The Scandi- 2007) and Spain (e.g. Poquet & Mesquita-Joanes navian Mountains are the major factor, so on the 2011). However, data on the assemblages occur- western slopes annual precipitation amounts to ring in northern and temperate Europe are still about 4000 mm near Bodø in Norway, whereas lacking. in the rain shadow to the east decreases abruptly The main goals of this study were (1) to to < 400 mm in Finnmark and Finish Lapland. conduct faunistic surveys of ostracod assem- In the east part of Lapland snow cover persists blages in three types of freshwater habitats: tem- for more than six month (Pulkkinen & Rissanen, porary waters, peat-bogs and shallow riparian 1997, Stebel et al. 2007). water of lakes in two geographically and physi- In Poland, climatic conditions are shaped ographically different regions, northern subar- predominantly by location, and its continental ctic Europe (Norwegian and Finnish Lapland) climate is modified latitudinally by the increase and central temperate Europe (Poland); (2) to in altitudes from the lowlands of northern Poland compare ostracod species diversity and richness to high altitudes of the Carpathian Mountains among these habitats and regions; (3) to perform in the south. The coldest month is usually Janu- zoocoenological analysis in an attempt to distin- ary, when mean temperatures range from about guish ostracod assemblage types characteristic –1 °C near Szczecin in NW Poland to –8 °C and indicative of the studied habitats, (4) to in the Tatra Mountains in the south. The mean investigate relationships between the occurrence temperature in July, the warmest month, is 17 °C of particular ostracod species and abiotic envi- along the north coast of Poland but 19 °C in ronmental factors, and (5) to assess usefulness of the south and east. The amount of precipita- ostracods as indicators of environmental condi- tion depends largely on altitude: in the wettest tions in freshwater habitats. regions of the Carpathian Mountains and the uplands of southern Poland, rainfall ranges from 1000 to 1700 mm per year, but in the lowlands Study areas and regional settings the rain-shadow effect restricts precipitation to < 500 mm per year (Martyn 1995). Our studies were focused on two physiographi- cally and climatically different European regions, latitudinally ca. 2000 km apart: one in north- Material and methods ern subarctic Europe, namely Lapland (66°28´– 69°20´N, 15°24´–27°54´E), and the other in cen- Ostracod samples and environmental data were tral temperate Europe, Poland (50°28´–54°27´N, collected at 49 stations: 24 in Lapland (L1–L24) 15°36’–23°24´E). In this paper, the term “Lap- and 25 in Poland (P1–P25) (Fig. 1). Of the 24 land” is applied to the regions of Norwegian and sites in Lapland, all sampled in July 2006, 7 Finnish Lapland. were in northern Norway, while the remaining Climatic conditions in Lapland are influenced 17 were in four provinces of Finland. In Poland, by two opposing factors. The maritime zone is samples were collected from 25 sites scattered strongly influenced especially in winter by air over the whole country (Fig. 1 and Table 1). Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 195

Fig. 1. Location of the studied sampling sites in Lapland and Poland.

Sampling sites were selected to represent cod samples were collected using a hand-net three types of freshwater habitat: (1) temporary (120 µm mesh size) from the bottom surface of waters (eight sites in Lapland and eleven sites 1 m2 at depths to max. ~60 cm (i.e. arm’s reach). in Poland), (2) peat-bogs (eight and seven sites, Samples were preserved in the field in 75% etha- respectively), and (3) shallow riparian water of nol, and later in the laboratory washed with tap lakes (eight and seven sites, respectively). Ostra- water through a 120 µm sieve and preserved in 196 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49

Table 1. Geographical location and habitat description of the sampling sites in Lapland (L1–L24) and in Poland (P1–P25). Abbreviations of biogeographical provinces in Lapland after Väisänen et al. (1992): Le = Lapponia Enon- tekiö, Li = Lapponia Inari, Lk = Lapponia Kemi, NNØ = Northeastern Nordland, NSI = Inner Southern Nordland, Ob = North Ostrobottnia, TRI = Inner Troms. Numbers of zoogeographical regions in Poland according to Catalogue of the Fauna of Poland: 3 = Pomeranian Lake District, 4 = Masurian Lake District, 6 = Mazovian Lowland, 8 = Lower Silesia, 12 = Lubelska Upland, 13 = Roztocze Upland, 15 = Western Sudeten Mts.).

Code Site Date of Habitat type Lat. N Long. E Altitude (province/region) collection (m a.s.l.)

Lapland L1 Semska (NSI) 6 July 2006 temporary 66°40´13´´ 15°24´28´´ 673 L2 Kvitblik (NNØ) 6 July 2006 temporary 67°23´06´´ 15°38´58´´ 56 L3 Marsvikbotn (NNØ) 6 July 2006 peat-bog 67°44´50´´ 15°54´55´´ 326 L4 Innhavet (NNØ) 7 July 2006 peat-bog 68°00´50´´ 16°01´29´´ 32 L5 Bjerkvik (TRI) 7 July 2006 lake 68°36´31´´ 17°37´59´´ 271 L6 Setermoen (TRI) 7 July 2006 temporary 68°49´40´´ 18°13´18´´ 155 L7 Heia (TRI) 8 July 2006 lake 69°09´22´´ 19°02´49´´ 175 L8 Kilpisjärvi (Le) 8 July 2006 temporary 68°55´24´´ 20°56´32´´ 566 L9 Luspa (Le) 8 July 2006 temporary 68°32´02´´ 22°01´08´´ 387 L10 Jatuni (Le) 9 July 2006 peat-bog 68°26´25´´ 22°35´54´´ 337 L11 Kaamasmukka (Li) 12 July 2006 temporary 69°20´15´´ 26°33´57´´ 247 L12 Karhujärvi (Li) 12 July 2006 lake 69°11´26´´ 26°56´06´´ 246 L13 Kaamanen (Li) 12 July 2006 peat-bog 69°08´10´´ 27°13´20´´ 135 L14 Mukkajärvi (Li) 14 July 2006 peat-bog 69°04´21´´ 27°20´42´´ 154 L15 Kontionojansuu (Li) 14 July 2006 lake 69°08´46´´ 27°47´22´´ 129 L16 Pekkala (Li) 14 July 2006 temporary 69°14´35´´ 27°54´37´´ 142 L17 Sellaniemi (Li) 15 July 2006 peat-bog 68°52´20´´ 27°09´27´´ 152 L18 Menesjärvi (Li) 15 July 2006 peat-bog 68°43´54´´ 26°24´22´´ 205 L19 Riistinalompolo (Li) 16 July 2006 peat-bog 68°41´08´´ 27°28´55´´ 145 L20 Torppar (Li) 16 July 2006 lake 68°39´22´´ 27°46´35´´ 127 L21 Pokka (Lk) 17 July 2006 temporary 68°07´16´´ 25°35´27´´ 294 L22 Sirkka (Lk) 9 July 2006 lake 67°49´31´´ 24°49´50´´ 191 L23 Marrakoski (Ob) 18 July 2006 lake 66°47´17´´ 25°26´31´´ 94 L24 Rovaniemi Town (Ob) 18 July 2006 lake 66°28´19´´ 25°36´58´´ 71 Poland P1 Kamień (3) 26 Aug. 2006 peat-bog 54°27´44´´ 18°15´34´´ 200 P2 Otomin Lake (3) 27 June 2008 lake 54°19´11´´ 18°29´49´´ 132 P3 Otomin Peat-bog (3) 27 June 2008 peat-bog 54°18´48´´ 18°30´51´´ 103 P4 Wdzydze (3) 28 May 2008 peat-bog 54°00´37´´ 17°58´33´´ 158 P5 chądzie (3) 28 May 2008 peat-bog 54°00´03´´ 17°59´45´´ 138 P6 Krzywe (3) 28 May 2008 peat-bog 53°58´36´´ 17°57´45´´ 138 P7 Filipówka (4) 12 May 2006 temporary 54°03´52´´ 21°17´09´´ 124 P8 Pożarki (4) 12 May 2008 temporary 54°02´11´´ 21°30´09´´ 128 P9 Tynwałdzkie (4) 12 Sep. 2006 lake 53°39´55´´ 19°38´42´´ 117 P10 Stęgwica (4) 12 Sep. 2006 lake 53°38´56´´ 19°32´19´´ 74 P11 Silm (4) 16 June 2008 lake 53°36´53´´ 19°30´58´´ 144 P12 Jeziorak (4) 16 June 2008 lake 53°35´59´´ 19°33´16´´ 89 P13 Karaś (4) 12 Sep. 2006 lake 53°33´42´´ 19°29´40´´ 95 P14 chojnowo (6) 12 May 2006 temporary 53°01´15´´ 20°47´02´´ 150 P15 Pniewo (6) 12 May 2006 temporary 52°39´21´´ 21°13´41´´ 100 P16 Ostrów (6) 25 Apr. 2007 temporary 52°06´07´´ 21°24´04´´ 152 P17 Garwolin (6) 25 Apr. 2007 temporary 51°52´52´´ 21°37´50´´ 145 P18 Wilków (8) 21 Apr. 2006 temporary 51°41´50´´ 16°12´51´´ 78 P19 Wilczków (8) 20 Apr. 2006 lake 51°11´05´´ 16°29´33´´ 123 P20 Kwietno (8) 20 Apr. 2006 temporary 51°10´13´´ 16°28´21´´ 136 P21 Łupki (15) 19 Apr. 2006 temporary 51°02´14´´ 15°36´17´´ 290 P22 Zamość (12) 24 Apr. 2007 temporary 50°44´29´´ 23°16´32´´ 208 P23 Zwierzyniec (13) 18 May 2008 peat-bog 50°33´03´´ 23°00´39´´ 269 P24 Tarnowola (13) 18 May 2008 peat-bog 50°29´26´´ 23°01´06´´ 252 P25 Dąbrowa Tomaszowska (13) 24 Apr. 2007 temporary 50°28´39´´ 23°24´58´´ 281 Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 197

95% ethanol. Ostracods were identified under a (LSL), shallow riparian water of lakes in Poland microscope using both valve and soft body char- (PSL), temporary waters in Lapland (LTW) and acteristics using the keys of Sywula (1974) and temporary waters in Poland (PTW). Each time Meisch (2000). 1000 random or actual (if < 1000) number of A suite of physical and chemical variables permutations was used to obtain r values and (Appendices 1 and 2) were measured at each site. probability levels. Water temperature, dissolved oxygen content, To detect the main patterns and gradients of salinity, conductivity and pH were measured in diversity in particular environmental variables situ using a hand-held multi-parameter instru- and to assess how the sampling sites differed ment (WTW Multi 350i). Phosphate, nitrate, iron from each other in abiotic conditions, an uncon- and calcium ions in the water were measured strained ordination of the Principal Components using colorimetric tests. A Secchi disc was used Analysis (PCA) was used on the basis of the to assess water transparency. Sediment proper- Euclidean distance matrix, calculated from the ties, like organic matter and water content, were standardised values of the studied environmental assessed back in the laboratory using the stand- variables. ANOSIM was also employed in this ard procedure of Håkanson and Jansson (2002). analysis (Clarke & Warwick 2001). In the faunistic and community analyses, To explain and describe the relationships only samples containing > 30 indiv. m–2 were between the ostracod species/assemblages and considered. Relationships between ostracod site the environmental factors, two methods were assemblages were examined using UPGMA employed: Canonical Correspondence Analy- (Unweighted Pair Group Method with Arith- sis (CCA), a method of constrained ordination metic mean) hierarchical clustering based on detecting main patterns of dependence between square-root transformed species abundances per two datasets of variables (ter Braak & Šmilauer square meter and the Bray-Curtis similarity coef- 2002), and BEST, which analyses every possible ficient. A “similarity profile” (SIMPROF)- per combination of variables within the two matri- mutation method (with 999 simulations) was ces (environmental and faunal). BEST detects implemented with the UPGMA procedure to test a subset of environmental variables which best the null hypothesis that samples in a given clus- explains the samples ordination based on the ter (representing a group of similar site assem- faunal matrix (for details see Clarke & Warwick blages) do not differ from each other in their 2001 and Clarke & Gorley 2006). multivariate structure (Clarke & Warwick 2001, Finally, biodiversity of site assemblages was Clarke & Gorley 2006). Additionally, after the estimated using both the standard measure of cluster analysis, individual species contributions the Shannon-Wiener diversity index (H´), and to the observed clustering pattern were examined the average taxonomic distinctness (Δ+) which using “similarity percentages” (SIMPER), a pro- is a measure based on relatedness of species cedure that allows assessment of which species (Clarke & Warwick 1998). To test whether a are principally responsible for the separation of set of species occurring at a sampled site has the sets of samples (assemblage types) (Clarke & the same taxonomic distinctness structure as a Warwick 2001, Clarke & Gorley 2006). so-called “master” list (i.e. an inventory of all The analysis of similarities (ANOSIM), a species in a given biogeographical region) from non-parametric permutation test (Clarke & War- which it was drawn, the Taxonomic Distinct- wick 2001), was used to investigate associations ness Test (TAXDTEST) was performed (with between the site assemblage structure and both 1000 random simulations) and the results were the study region, and the type of habitat within presented as a funnel plot (for details see Clarke the region. For ANOSIM, sampling sites were a & Warwick 2001 and Clarke & Gorley 2006). priori grouped according to two criteria: (1) the The checklist of Silfverberg (1999) as updated region (two groups: Lapland and Poland), and by Iglikowska and Namiotko (2010) and supple- (2) the habitat type within the region (six groups: mented by the records from the Fauna Europaea peat-bogs in Lapland (LP), peat-bogs in Poland database (Horne 2004) was adopted as the inven- (PP), shallow riparian water of lakes in Lapland tory of non-marine ostracod species for Fennos- 198 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49 candia, whereas for Poland, the updated checklist Wallis test: H = 10.7, p < 0.01; H´ = 1.902 for of non-marine ostracods by Namiotko (2008) PSL, H´ = 1.245 for PTW and H´ = 0.755 for served as the master faunal list. The higher classi- PP). fication of the ostracods followed Meisch (2000). In this study, 56% of the identified spe- All statistical procedures were run in the cies are considered to reproduce sexually, 29% PRIMER ver. 6.1.10. programme (Clarke & are characterized by the sporadic appearance of Gorley 2006), except CCA which was performed males, and 15% are exclusively parthenogenetic. using CANOCO ver. 4.56. (ter Braak & Šmilauer In Lapland, the most widespread and abun- 1997–2009) software. dant species were Candona candida and Cyclo- cypris ovum, each dominating at nine sites (38% of the Lapland sites: Appendices 3 and 4) with Results an average relative abundance of 37% and 39%, respectively. A third most numerous species in A total of 40 300 ostracods were collected from Lapland was Pseudocandona rostrata with an all study sites (11 157 from Lapland and 29 143 average proportion of 10%. Rare species at the from Poland). At six sites (L5, L10, L23 in Lap- Lapland sites included the crenophilic species land and P1, P18, P21 in Poland), no ostracods Cryptocandona reducta, C. vavrai, and Eucypris were found. The main reasons for the absence pigra as well as Pseudocandona albicans. Only was probably either poor environmental condi- one boreal/arctic species — Fabaeformiscan- tions: low pH (L10 = 4.3, P1 = 4.2), low calcium dona lapponica — was recorded in this area. content (L5 and L23 = 10 mg dm3), and low min- In Poland, the dominance structure of the eralization (conductivity L5 = 60.8, L10 = 56.3, ostracod site assemblages was determined by L23 = 57.5, P1 = 44.9, P21 = 64.3 µS cm), or too habitat type. In shallow lakes (PSL), no distinct short time for colonization of a new reservoir, and common dominant species were found, but when a temporary pond re-fills after drought those which were the most abundant (average (P18 and P21). proportion > 5% in PSL) comprise species of the The average abundance of ostracods in the genus Pseudocandona (both from the compressa remaining samples was 3061 ± 5450 ind. m–2 and rostrata groups, in total ca. 36%) as well (mean ± SD). A total of 41 ostracod species were as Cyclocypris laevis (25%), Metacypris cor- identified (Appendices 3 and 4) — 15 in Lapland data (12%), Candona weltneri (7%), and Can- and 35 in Poland. The average number of species donopsis kingsleii (6%) (Appendices 3 and 4). In per site (species richness) was 4.3 ± 1.4 in Lap- temporary waters (PTW), the dominant species land and 6.3 ± 3.0 in Poland, and this difference included Bradleystrandesia reticulata and Cypris was significant (Mann-Whitney test: U = 114.4, pubera (both with the average proportion of p < 0.05). ca. 30% in PTW), while Eucypris virens (13%) Significant differences in the average spe- and Pseudocandona pratensis (8%) contributed cies richness per sampling site within the habitat smaller proportions. In the majority of the peat- types, were found only in Poland: on average bogs in Poland (PP), either no ostracods or only 10.1 ± 0.7 species per site in PSL (the riparian a few individuals were found (Appendices 3 and shallow lake waters), 4.1 ± 2.5 in PTW (the 4). At the few peat-bog sites at which ostracods temporary waters), and 2.6 ± 3.1 in PP (the peat- occurred, one species was always highly domi- bogs) (Kruskal-Wallis test: H = 15.2, p < 0.001). nant, either Cyclocypris globosa, Cypria ophtal- In Lapland, the species richness was similar at mica or Pseudocandona stagnalis. sites representing all three habitat types: 4.2 ± In the UPGMA cluster analysis (Fig. 2), four 1.5 in LSL, 4.4 ± 0.7 in LTW, and 3.7 ± 2.1 in LP types of ostracod assemblages were identified (Kruskal-Wallis test: H = 3.0, p = 0.224). and subsequently validated by the SIMPROF Also differences between average values of significance test (π = 3.95–4.50, p = 0.01). The the Shannon-Wiener diversity index for assem- characteristic species (indicated by the SIMPER blages representing the three habitat types were analysis) of the first assemblage type including statistically significant only in Poland (Kruskal- all site assemblages from the shallow riparian Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 199

0

20

40

y

Similarit 60

80

100

L3 L1 L6 L9 L7 L2 L8

P6 P7

P8 P2 P9 P5

L18

L14 L24 L19 L17 L20 L11 L16 L21

L22 L12 L15 L13

P23 P14 P22 P17

P25 P20 P15 P16 P19 P11 P12 P13 P24 P10 Sites reg/hab LTW LP LSL PSL PTW PP

Fig. 2. The UPGMA dendrogram obtained on the basis of Bray-Curtis similarity (%) matrix among ostracod assem- blages from the sampling sites in Poland and Lapland. Statistically significant separations of the genuine clusters (i.e. main ostracod assemblage types) demonstrated by the SIMPROF test are marked by solid lines (all other branches dashed lines = no statistical evidence for any sub-separation was found). Abbreviations of the habitat types within the studied regions: LTW = temporary waters in Lapland, PTW = temporary waters in Poland, LSL = shallow riparian water of lakes in Lapland, PSL = shallow riparian water of lakes in Poland, LP = peat-bogs in Lap- land, and PP = peat-bogs in Poland. Sampling sites codes as in Table 1. water of lakes in Poland (PSL) were: Pseudo- ostracod site assemblages from temporary waters candona spp. (usually represented by juveniles in Poland (PTW) (Fig. 2) was characterised by not determined to species level), Candonopsis four species already mentioned above: Cypris kingsleii, Cypridopsis vidua, and Cypria ophtal- pubera, Bradleystrandesia reticulata, Eucypris mica as well as Cyclocypris laevis and Meta- virens and Pseudocandona pratensis (Table 2). cypris cordata (Table 2), although the latter two The third assemblage type linked only two occurred at less than 3/4 of sites. Darwinula ste- peat-bog sites in Poland (P6 and P23) and one vensoni was not abundant but a relatively regular peat-bog site in Lapland (L18) (Fig. 2), and inhabitant of the shallow lakes in Poland. The displayed an average faunal similarity of only average mutual Bray-Curtis similarity between 19.6%. The main feature of these sites was the site assemblages representing this assem- the 100% frequency of occurrence of Pseu- blage type was 36.8%. docandona stagnalis, as well as a simultane- The second slightly less coherent (average ous presence of Cyclocypris globosa and Brad- faunal similarity between site assemblages of leystrandesia reticulata (Table 2 and Appendices 27.0%) assemblage type, which included all the 3 and 4). 200 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49

The last assemblage type was defined by a the sites within this assemblage type) as well as major cluster and consisted of all but one (see Cyclocypris ovum and Pseudocandona rostrata above) site assemblages from Lapland and two (each found at 71% sites) (Table 2). The average assemblages from peat-bog sites in Poland (P5 similarity between all pairs of site assemblages and P24; Fig. 2). The main species indicated in this cluster was 31.8%. by the SIMPER analysis as principally respon- According to the ANOSIM test carried out sible for the separation of this set of samples using the faunal data, there were statistically sig- included Candona candida (occurring at 95% of nificant differences in the site assemblage struc-

Table 2. Frequency of occurrence (%) of ostracod species at the sampling sites representing three habitat types within the two studied regions: LTW = temporary waters in Lapland, LP = peat-bogs in Lapland, LSL = shallow ripar- ian water of lakes in Lapland, PTW = temporary waters in Poland, PP = peat-bogs in Poland, PSL = shallow riparian water of lakes in Poland. Detailed data on the abundance of the identified species at particular sampling sites is given in Appendices 3 and 4.

Species LTW LP LSL PTW PP PSL

Darwinula stevensoni – – – – – 86 Candona candida 100 71 83 – 17 71 Candona weltneri – – – – – 43 Candonopsis kingsleii – – – – 17 86 Fabaeformiscandona fabaeformis – – – 11 17 Fabaeformiscandona hyalina – – – – – 57 Fabaeformiscandona lapponica – 14 – – – Pseudocandona hartwigi – – – – – 43 Pseudocandona marchica – – – – 17 29 Pseudocandona rostrata 88 57 67 – – Pseudocandona stagnalis – 14 – – 67 Pseudocandona albicans – – 17 11 – Pseudocandona compressa – – – – – 57 Pseudocandona insculpta – – – – – 71 Pseudocandona pratensis – – – 56 – Pseudocandona sucki – – – 33 – Cryptocandona reducta – 14 – – – Cryptocandona vavrai 25 – 17 – – Paracandona euplectella – – – – 17 Cyclocypris globosa – 29 – – 33 Cyclocypris laevis – – – 22 33 57 Cyclocypris ovum 75 29 83 11 33 43 Cyclocypris serena 25 14 33 – – Cypria exsculpta – – – – – 14 Cypria ophtalmica 13 14 17 11 17 86 Ilyocypris decipiens – – – – – 14 Ilyocypris gibba – – – – – 14 Notodromas monacha – – – – – 14 Cyprois marginata – – – 11 – Cypris pubera – – – 78 – Cypridopsis vidua 38 29 50 11 17 100 Bradleystrandesia fuscata – – – 11 – Bradleystrandesia reticulata 50 43 17 56 17 Eucypris crassa – – – 33 – Eucypris pigra – 14 – – – Eucypris virens – – – 78 – Tonnacypris lutaria – – – 56 – Heterocypris incongruens – – – 11 – Dolerocypris fasciata 25 14 17 – – 29 Limnocythere inopinata – – – – – 43 Metacypris cordata – – – – – 71 Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 201

Fig. 3. The biplot display- 4 ing PCA ordination of the reg/hab investigated sites (L1–L24 LTW in Lapland and P2–P25 LP in Poland, as in Table 1) LSL P25 based on environmental L12 PSL factors. First axis (PC1) 2 L13 trans L2 PTW explains 34.4% and L11 L21 L22 OmgpH PP second axis (PC2) 14.2% L19 L18 lat L3 L1 P13 P11 of total variability. Abbre- L17 P7 P22 L15 L7 long P2 P20 viations of habitat types L9 cond L16 L6 alt P12 within the studied regions L8 P9 P19 0 Ca P15 as in Fig. 2. Environmental PC2 hydr L24 P10 PO P16 factors and geographical L14L20 temp data: lat = latitude, long org L4 P8 P17 = longitude, alt = altitude, P5 P14 temp = water tempera- Fe ture, trans = transparency, –2 Omg = dissolved oxygen P4 content, cond = conductiv- P23 P6 ity, Fe = iron ion content, P24 Ca = calcium ion content, P3 PO = phosphate content, org = organic matter con- –4 tent of bottom sediment, –4 –2 0 2 4 6 hydr = water content of bottom sediment. PC1

ture between Poland and Lapland (r = 0.363, as well as organic matter and the water content of p < 0.001). However, when the analysis was the bottom sediments. Four abiotic factors were conducted assuming a grouping by habitat type responsible for separation of the peat-bogs from within the region (six sets of site assemblages), Poland (PP): (1) high content of organic matter the differences between the habitat types were in sediment, (2) high content of dissolved iron significant only in Poland (r ≥ 0.599, p ≤ 0.002). in the water, (3) low concentration of dissolved All the site assemblages in Lapland had a homo- oxygen, and (4) low pH. The temporary waters geneous species composition regardless of habi- in Poland (PTW) and the shallow riparian waters tat (r < 0.063, p > 0.189; Table 3). of lakes in Poland (PSL) were both defined by: The PCA ordination of the sampled sites (1) conductivity, (2) pH, (3) dissolved oxygen showed that the first three axes explained 59.2% content, and (4) dissolved phosphate and nitrate of the total variation (Fig. 3). The factors which content. Moderate values of these factors were determined most of the variance in all sampled typical fo the PSL sites, whereas high (and very sites were conductivity and calcium ion content, high) values typified the PTW sites. The sites in

Table 3. Values of r and respective probabilities (in parentheses) of the ANOSIM test carried out using the faunal data for six a priori ascertained groups of site assemblages (temporary waters in Lapland LTW, temporary waters in Poland PTW, shallow riparian water of lakes in Lapland LSL, shallow riparian water of lakes in Poland PSL, peat- bogs in Lapland LP and peat-bogs in Poland PP). Values indicating statistically significant differences are set in boldface.

LTW LP PSL PTW PP

LSL 0.052 (0.258) 0.063 (0.188) 0.926 (≤ 0.001) 0.825 (0.002) 0.504 (0.002) LTW –0.017 (0.483) 0.948 (≤ 0.001) 0.842 (≤ 0.001) 0.566 (≤ 0.001) LP 0.618 (≤ 0.001) 0.671 (≤ 0.001) 0.214 (0.046) PSL 0.874 (≤ 0.001) 0.599 (0.002) PTW 0.714 (≤ 0.001) 202 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49

Lapland, regardless of habitat, formed a single was excluded as a result of forward selection. cluster distinguished by: (1) high transparency Five variables appeared significant and most of the water, (2) high organic matter content and important in explaining the observed ostracod water content of the bottom sediment (for values distribution (Fig. 4): Ca (F = 5.71, p = 0.002, of environmental variables measured at particu- λA = 0.65), pH (F = 3.27, p = 0.002, λA = 0.35), lar sites see Appendices 1 and 2). water conductivity (F = 3.17, p = 0.002, λA = The ANOSIM analysis carried out on the 0.32), organic matter content of the sediment matrix of environmental factors confirmed the (F = 2.09, p = 0.004, λA = 0.20) as well as dis- division of sites into two regional groups (r = solved oxygen content (F = 2.04, p = 0.002, λA 0.379, p < 0.001). When grouping the sites by = 0.20). Conductivity and Ca content had the habitat type within the region, however, the only strongest correlations with the first canonical statistically significant differences were found in axis, whereas pH and organic matter content of Poland between sites representing three different bottom sediment correlated with the second axis. habitats (r ≥ 0.252, p ≤ 0.015; Table 3), reflect- As can be seen in the CCA plot (Fig. 4) there ing the results obtained from the faunal data (see is an interdependence between high values of above and Table 4). dissolved oxygen, conductivity and calcium con- After the estimation of the gradient length tent, and abundances of Bradleystrandesia fus- by Detrended Correspondence Analysis (5.802), cata, Cypris pubera, Cyprois marginata, Eucyp- the CCA ordination was performed to explore ris crassa, E. virens, Heterocypris incongruens, the relationships between independent (environ- Pseudocandona albicans, P. pratensis, P. sucki mental) and dependent (species abundance) vari- and Tonnacypris lutaria. These species, which ables. The first two axes accounted for 60.6% are plotted on the right side in Fig. 4, are char- of the total variance of the species–environ- acteristic of temporary waters. In the bottom-left ment relation, and the species–environment cor- sector of the plot there are a number of species relations were 0.938 for the first axis and 0.791 (Candona weltneri, Candonopsis kingsleii, Cyp- for the second axis (Table 5). In the analysis, ridopsis vidua, Darwinula stevensoni, Fabaefor- latitude was taken as a covariable and longitude miscandona hyalina, Limnocythere inopinata,

Table 4. Values of r and respective probabilities (in parentheses) of the ANOSIM test carried out using the environ- mental variables for six a priori ascertained groups of sites (abbreviations as in Tables 2 and 3). Values indicating statistically significant differences are set in boldface.

LTW LP PSL PTW PP

LSL 0.010 (0.394) –0.076 (0.935) 0.681 (≤ 0.001) 0.657 (≤ 0.001) 0.894 (≤ 0.001) LTW –0.013 (0.541) 0.534 (≤ 0.001) 0.600 (≤ 0.001) 0.700 (≤ 0.001) LP 0.567 (≤ 0.001) 0.713 (≤ 0.001) 0.623 (0.002) PSL 0.252 (0.015) 0.710 (≤ 0.001) PTW 0.751 (≤ 0.001)

Table 5. Summary of the results of the CCA performed on 43 active samples and 41 active species.

Axes 1 2 3 4 Total inertia

Eigenvalues 0.692 0.350 0.321 0.200 Species-environment correlations 0.938 0.791 0.870 0.842 5.762 Cumulative percentage variance of species data 13.4 20.2 26.4 30.2 of species–environment relation 40.3 60.6 79.3 90.9 Sum of all eigenvalues 5.171 Sum of all canonical eigenvalues 1.720 Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 203

org

cond Axis 2 (6.8%)

Omg Ca

pH

Axis 1 (13.4%) Fig. 4. The CCA ordination of ostracod assemblages and environmental factors in the space defined by the first two canonical axes. Only 26 best fit species were taken into consideration: Bf = Bradleystrandesia fuscata, Cw = Can- dona weltneri, Ck = Candonopsis kingsleii, Cg = Cyclocypris globosa, Co = Cypria ophtalmica, Cv = Cypridopsis vidua, Cp = Cypris pubera, Cm = Cyprois marginata, Ds = Darwinula stevensoni, Ec = Eucypris crassa, Ev = Eucy- pris virens, Ff = Fabaeformiscandona fabaeformis, Fh = Fabaeformiscandona hyalina, Hi = Heterocypris incongru- ens, Li = Limnocythere inopinata, Mc = Metacypris cordata, Pe = Paracandona euplectella, Pa = Pseudocandona albicans, Pc = Pseudocandona compressa, Pi = Pseudocandona insculpta, Pp = Pseudocandona pratensis, Ps = Pseudocandona stagnalis, Psu = Pseudocandona sucki, Pseud = Pseudocandona sp., rostrata = the species group rostrata of the genus Pseudocandona, Tl = Tonnacypris lutaria. Five environmental factors which appeared statisti- cally significant are indicated (codes as in Fig. 3) and latitude was considered as a covariable.

Metacypris cordata, Pseudocandona compressa, abundances proved to be associated with low P. insculpta, Pseudocandona sp. and rostrata pH, high organic matter content in the bottom group) the abundances of which are correlated sediment, low values of dissolved oxygen and with high oxygen content values and high pH. low calcium content. Finally, it is worth noticing Furthermore, the abundances of the aforemen- that species characteristic for Lapland are absent tioned species revealed negative correlation with from the plot (only the 26 best fitted species iron content (e.g. C. kingsleii Spearman’s cor- were taken into consideration) as a consequence relation: r = –0.42, p < 0.01 and D. stevensoni of a lack of any strong relationships between r = –0.44, p < 0.01). In the upper-left sector of ostracod abundances and environmental factors the plot, there are species that are characteristic in Lapland. of Polish peat-bogs, namely Cyclocypris glo- The BEST analysis selected six significant bosa, Cypria ophtalmica, Fabaeformiscandona and most important environmental factors and fabaeformis, Paracandona euplectella and Pseu- geographical variables determining the grouping docandona stagnalis, and their occurrences and of the ostracod site assemblages into four main 204 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49 clusters (Fig. 2), i.e. four assemblage types (r = 53.25 ± 11.99). However, the power of the per- 0.503, p = 0.01), these were: latitude, pH, con- formed test was low because most of the assem- ductivity, dissolved iron content, phosphates and blages from the peat-bogs (four of seven) had organic content of the bottom sediment. Remark- to be excluded from the analysis due to the low ably four of these (latitude, pH, conductivity and abundances (less than 30 ind. m2) and species organic matter content) also appeared as signifi- richness (less than two species) of the samples. cant in the CCA ordination. Latitude naturally separates all ostracod assemblages found in Poland (< 54°27´N) from those found in Lapland Discussion (> 66°28´N). Low pH segregates assemblages of acidic sites (pH < 5.3 in peat-bogs in Poland) In this study of three types of freshwater habitats from all the other assemblages at sites which are (temporary waters, shallow riparian water of lakes characterized by more alkaline conditions with and peat-bogs) in Poland, a total of 35 ostracod moderate to high pH values. Conductivity subdi- species was identified, which constitutes 25% of vides the ostracod assemblages into three groups: the total number of modern fresh- and brackish- (1) assemblages of low conductivity sites (< 180 water ostracod species reported from Poland (140, µS cm–1) in Lapland and the peat-bogs in Poland, see Namiotko 2008). In the Lapland sites repre- (2) assemblages of moderate conductivity sites senting the same three habitat types, 15 species of shallow lakes in Poland, and (3) assemblages were found representing 42% of the total number of the highly mineralised (> 800 µS cm–1) tem- of freshwater ostracod species recorded in this porary waters in Poland. Dissolved iron con- region, i.e. 36 species reported the overall from tent is a factor that typifies assemblages of the the Norwegian, Swedish, Finnish and Russian shallow lakes in Poland where values are close parts of the Fennoscandia north of the Arctic to zero (< 0.05 mg dm–3). Low phosphate con- Circle (according to Sars 1890, Ekman 1908, tent (< 0.25 mg dm–3) characterizes assemblages 1914, Alm 1914a, 1914b, 1915, Sars 1925, Aka- –3 occurring in Lapland, moderate PO4 values tova & Järvekülg 1965, Vekhov 2001, Iglikowska characterize assemblages of Polish shallow lakes & Namiotko 2004, 2010). No species new to –3 and peat-bogs, whereas very high PO4 values Norway, Finland or Poland were collected. (> 1.00 mg dm–3) are typical from assemblages In Poland, there were statistically significant from temporary waters. Finally, organic matter differences in average species richness (number content in the sediment typifies the assemblages of species) of ostracod site assemblages occur- found in Polish peat-bogs. ring in the three different habitat types. The high- Funnel plots (Fig. 5) were generated using est number of species was collected from lake TAXDTEST to compare the taxonomic diver- sites and the lowest from peat-bogs. Thus shallow sity (expressed as Δ+) of the ostracod assem- riparian lake habitats seem to provide more suit- blages found in Poland and in Lapland relative able and more stable environmental conditions to the known non-marine ostracod diversity of for ostracods as compared with temporary astatic the corresponding region. They show that in both waters and peat-bogs. An important factor result- regions the ostracod assemblages are representa- ing in high ostracod species richness in lakes is tive of the known regional taxonomic diver- the presence of emergent vegetation in the ripar- sity. It is noteworthy that in Poland there were ian zone, which creates a broad range of ecologi- statistically significant differences in the - aver cal niches (Cooke et al. 2001, Søndegaard et al. age taxonomic distinctness (Δ+) between the 2005). In peat-bogs and temporary pools we stud- habitat types (Kruskal-Wallis test: H = 10.08, p ied, emergent vegetation was either non-existent = 0.007), the highest Δ+ values were typical for or sparse, so the ostracod fauna was relatively the assemblages from shallow lakes (PSL), while poor in species. Habitats provided by temporary moderate values were found for those from tem- waters are highly specific, inhabiting organisms porary waters (PTW) and peat-bogs (PP) (mean have relatively short life cycles, an ability to Δ+ value ± SD for PSL = 75.76 ± 7.13 versus survive desiccation, and tolerate high and fluc- that for PTW = 66.71 ± 4.35 and that for PP = tuating concentrations of dissolved organic and Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 205

100

90

80

70

+ 60

Δ

50

40 reg/hab LP 30 LSL LTW 20 Fig. 5. Funnel plots of 2 3 4 5 6 7 8 Average Taxonomical Distinctness (Δ+) of the 100 ostracod assemblages in Poland (top) and in Lap- 90 land (bottom). Thin lines indicate limits within which 80 95% of the simulated values of the Δ+ coeffi- 70 cient are located, whereas

the central thick lines indi- + cate mean Δ+ for the full Δ 60 inventory of freshwater ostracods from Poland and 50 Fennoscandia, respec- tively. Various symbols as 40 indicated in the legends reg/hab represent the true values PSL 30 PP of Δ+ coefficient for the PTW investigated sites of the three habitat types within 20 two regions (codes as in 2 3 4 5 6 7 8 9 10 11 Fig. 2 and Table 2). Number of species inorganic matter (e.g. Williams 2006). Ostracods availability of dissolved calcium and other ions. inhabiting temporary pools are adapted to survive Freshwater ostracods have relatively large car- in such variable environments, they have desic- apaces, mainly composed of calcium carbon- cation-resistant stages (resting eggs or juvenile ate, therefore it is commonly believed that they and adult torpidity), short life cycles, photope- require quite high levels of available calcium riod-dependent egg hatching, parthenogenetic or in the environment to construct their carapace mixed (where both sexual and asexual lineages valves. However, we need to know more about occur) reproductive modes or can exhibit a bet- complexities of the valve calcification in ostra- hedging strategy (e.g. Horne 1993, Otero et al. cods (Mezquita et al. 1999a, Holmes & Chivas 1998, Mezquita et al. 2005, Martins et al. 2008). 2002). The extremely low diversity and abundance The distinction between the three habitat of ostracods observed in peat-bogs was most types in Poland was also revealed by the Shan- probably linked to low pH and resulting low non-Wiener diversity index. There were signifi- 206 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49 cant differences in the species diversity between As regards the reproductive mode, 23 of the assemblages from the three habitat types 41 species identified in the study are consid- (Kruskal-Wallis test: H = 10.74, p < 0.01). The ered to reproduce sexually (Meisch 2000). The highest values of the Shannon-Wiener diversity remaining 18 species probably reproduce par- index were found in the assemblages from shal- thenogenetically at the sampling sites, although low lakes in Poland, and probably reflected the for 11 of these, rare males or sexual populations relative permanence and low variability of these are reported in the literature (Meisch 2000). lacustrine environments, relative to temporary In Lapland, nine out of 15 recorded species waters and peat-bogs. Heino (2000) reported (60%) are known to be fully parthenogenetic that species diversity increases with the size of (consisting of female-only populations or with a lake, larger water bodies contain more habitats sporadic occurrence of rare males). On the other and consequently more potential niches (Søn- hand in Poland, 60% of all the the recorded degaard et al. 2005). In this study, the lakes had species reproduce sexually. The sex ratio in all the highest surface areas and hence the higher studied species was heavily biased in favour of values of the Shannon-Wiener diversity index. females, with one exception — Candona welt- Heino (2000) reported other factors influenc- neri at P9. In that case, sampling probably took ing diversity in lakes such as heterogeneity of place during the season when males dominated water habitat, provenance of bottom sediment the adult population, since in this species mature (autochthonous remains of Sphagnum mosses males and females are known to appear at dif- and humic materials versus allochthonous ferent times (Hiller 1972). In Poland, there was fallen leaves of deciduous trees and shrubs), a significant relationship between the ratio of and amount of riparian vegetation. The results parthenogenetic to sexual species and habitat reported herein add pH to Heino’s (2000) list of type (Kruskal-Wallis test: H = 14.08, p < 0.001). factors influencing diversity. Our results show The largest proportion of species with asex- a statistically significant correlation between ual reproduction was sampled from temporary pH and observed values of the diversity index waters (mean ± SD = 81.2% ± 29.2%), while (Spearman’s correlation: r = 0.46, p < 0.01). significantly lower proportions were observed Those sites typified by low environmental het- in peat-bogs (mean ± SD = 6.8% ± 13.4%) and erogeneity, with autochthonous bottom sediment shallow lakes (mean ± SD = 4.5% ± 2.5%). and lacking macrophytes were poorest in species Parthenogenesis enables a population to grow richness, conditions that are characteristic of rapidly, so that it can quickly exploit any new peat-bogs in Poland, where the lowest values of reservoir (e.g. when a temporary pond re-fills the diversity index were found. In Lapland, the after drought), thus asexual or mixed reproduc- average values of the Shannon-Wiener diversity tive strategies can be an advantageous adapta- index were similar in the three types of habitat, tion in unpredictable habitats (Horne & Martens and generally lower than in Poland (average H´ 1999, Mezquita et al. 2005, Martins et al. 2008). = 1.074 and 1.377 in Lapland and in Poland, In lakes and peat-bogs, the environmental condi- respectively). This is in accord with the gener- tions are generally more stable, and sexual repro- alization that species diversity decreases towards duction appears to be a more favourable mode. the north (Heino 2002, Willig et al. 2003). There Analysis of the assemblages in Lapland showed were significant differences in species diversity no statistically significant difference in the ratio between Poland and Lapland, but such a gradi- of parthenogenetic species between habitat type ent was not observed within the studied regions. (Kruskal-Wallis test: H = 0.105, p = 0.949). The influence of latitude on the species diversity Four types of ostracod assemblages were in the north may be the result of longer persist- distinguished using the UPGMA cluster analysis ence of the last glaciation at higher latitudes, (Fig. 2). The assemblage from temporary waters so that species had less time to colonize these in Poland was distinguished by four species: areas. History, however, does not seem to be the Cypris pubera, Eucypris virens, Bradleystran- only major determinant of species richness in the desia reticulata and Pseudocandona pratensis, northern areas (Heino 2002). which are characteristic of temporary pools Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 207

(Sywula 1974, Meisch 2000, Gifre et al. 2002). ity, temperature, oxygen and nutrient content Similarly, few species found in the assemblage (Gifre et al. 2002). Külköylüoğlu et al. (2007) from Polish peat-bogs (mainly Cyclocypris glo- also reported a positive correlation between E. bosa and Pseudocandona stagnalis) are typical virens abundance and conductivity but a nega- inhabitants of this habitat (Sywula 1965, 1974, tive one with pH. Fryer 1993, Meisch 2000). The assemblage type The lacustrine species were grouped in the in shallow riparian water of lakes in Poland, bottom-left sector of the CCA ordination plot consisted of two sets of species: (1) a group of (Fig. 4). These species correlate with environ- moderately dominant eurybiontic species (Cyp- mental factors such as high pH, and high content ridopsis vidua, Darwinula stevensoni, Cypria of dissolved oxygen. Phytophilic Cypridopsis ophtalmica, Cyclocypris laevis, Candonopsis vidua was recorded in a range of habitats, but kingsleii and Candona candida), and (2) a group it is most often found in lakes (Sywula 1974, of less abundant species typical of central Euro- Meisch 2000). This species is reported to require pean lakes (Candona weltneri, Pseudocandona high oxygen concentrations (≥ 5 mg dm–3) (Kiss insculpta, P. marchica, P. hartwigi, Metacypris 2007), and its oxyphilic nature was confirmed in cordata and Limnocythere inopinata) (Sywula the present study. The species was recorded at

1974, Meisch 2000). sites with an average O2 concentration of 6.2 mg In Lapland, we did not find a strong relation- dm–3. Cypridopsis vidua tolerates well a broad ships between abundances of the ostracod spe- range environmental factors, even relatively high cies and the observed environmental parameters, concentrations of pesticides (Külköylüoğlu et al. with one exception. The abundance of Candona 2007). However, it is doubtful whether C. vidua candida was negatively correlated with organic should be considered a polythermophilic species matter content in bottom sediments (r = –0.06, (Meisch 2000), since it is widespread and abun- p < 0.01). In contrast, abundance of this species dant in Lapland. An organism with high oxygen correlated positively with latitude (r = 0.59, p requirement is often well adapted to low water < 0.001), which implies that it prefers cooler temperatures (Mikulski 1982). waters of northern Europe. Kiss (2007) found The BEST analysis distinguished five envi- that this species’ abundance correlated nega- ronmental factors and one geographical variable tively with water temperature, and Külköylüoğlu which had significant impact on the grouping of et al. (2007) reported a negative correlation with the ostracod assemblages: pH, conductivity, Fe air temperature (r = –0.508, p < 0.05). Based on and phosphate contents, organic matter content our results and previous papers, C. candida is in sediment, as well as latitude. The influence of confirmed as an oligothermophilic species, pre- geographical position is most likely linked to cli- ferring oligotrophic conditions. matic effects. Mezquita et al. (2005) and Poquet Significantly stronger species–environment and Mesquita-Joanes (2011) showed latitude as relationships were found in Poland. The group of one of the most important factors determin- species consisting of Bradleystrandesia fuscata, ing the distribution of freshwater Ostracoda in Cypris pubera, Eucypris crassa, E. virens, Pseu- Europe. Species living in the north have to toler- docandona albicans, P. pratensis and P. sucki, ate not only low temperatures, but often also low which were placed on the right side of the CCA concentrations of dissolved ions and nutrients. plot (Fig. 4), appeared to be associated with rela- In Lapland, waterbodies are frozen for more tively high values of conductivity, oxygen con- than half a year, therefore, the species living tent and calcium content. High values of envi- there must be able to survive such conditions ronmental factors are characteristic of temporary at least during one stage of their life cycle. The pools, and E. virens almost exclusively inhabits Lapland sites were situated either on the western astatic water bodies (Sywula 1974, Mezquita slopes (sites L1–L7) or on the eastern slopes et al. 1999b, Meisch 2000, Gifre et al. 2002, (sites L8–L24) of the Scandinavian Mountains. Külköylüoğlu et al. 2007). This species tolerates Although east and west sites experienced signifi- not only high concentrations of dissolved sub- cantly different climatic regimes, there were no stances, but also significant fluctuations of salin- differences either in their environmental charac- 208 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49 teristics or in the abundances and species com- ontogeny (not every species can survive being position of the ostracod assemblages between frozen as mature or juvenile). Development can the two sides of the Mountains. take much longer in Lapland because of lower Many authors have reported that pH sig- water temperatures. Finally, the geological char- nificantly affects freshwater invertebrates (e.g. acter of the rocks may be important: in Lapland, Wickins 1984, Lampert & Sommer 1997, Ros- rocks are mostly acidic which results in natural setti et al. 2004, Martins et al. 2009, Martins et waters having low pH and being low in cal- al. 2010). Each aquatic organism has its own pH cium (Stebel et al. 2007). Both factors limit the optimum and tolerance range, but if pH exceeds diversity of the ostracod populations and in Lap- this range, species cannot survive because the land none of the observed ostracod species have regulation of pH within the organism is energeti- strongly calcified carapaces. cally too costly (Lampert & Sommer 1997). In northern Fennoscandia, numerous ponds Ionic content of the medium can have a and small lakes are a feature of the landscape, strong influence on the diversity of freshwa- in some parts of the region there are 1500 ter ostracods (e.g. Mezquita et al. 2005, Pieri waterbodies per 10 km2 (Raatikainen & Kuu- et al. 2007, 2009). The in situ ionic equilib- sisto 1990, Rautio et al. 2011). We infer that rium of water can have an effect on both the the majority of these waterbodies in Lapland osmoregulation and the physiological control of become temporarily connected during spring- an organism’s internal ionic balance. In fresh- time, when snowmelt water raises water levels, waters, calcium is often the critically limiting and hence facilitates the dispersion of aquatic ion, and crustaceans such as ostracods require organisms such as ostracods among all water calcium for their carapaces (Lampert & Sommer bodies and the colonization of new ones. Con- 1997). Calcium is effective in buffering pH, so sequently, not only do the environmental param- in Ca-depleted environments organisms are far eters become uniform throughout but also the more susceptible to extremes of pH (Wickins ostracod site assemblages are homogenized. This 1984). The importance of calcium availability inference is one of several possible hypotheses in controlling and limiting the post-embryonic that may explain our results: it however deserves development of ostracod individuals, as well further, more comprehensive investigation. as occurrence and diversity of ostracod species In Poland, the temporary pools and the peat- and assemblages has been demonstrated in sev- bogs are inhabited almost exclusively by sets eral works (e.g. Mezquita et al. 1999a, Holmes of ostracod species that are specific to these & Chivas 2002, Viehberg 2006), although the habitats. These species can be used as indicator intensity of the effects depends largely on spe- species for each of these habitats. cies. Temporary waters studied in Poland were The analysis of the relationships between the located in cultivated fields, in the vicinity of species composition and dominance in the ostra- villages and towns, or in roadside ditches. The cod assemblages indicated that in Lapland, the inflow into these temporary water bodies isby species diversity was lower than that in temper- rainwater running off fields or roads, potentially ate Poland and that most of the species recorded enriched with fertilizers, pesticides, manure and in the north appeared to be eurybiontic. No pollutants such as oil residues. Therefore, it is distinct differences in the structure of the ostra- not surprising that these temporary waterbod- cod assemblages among the three types of fresh- ies were found to contain high concentrations water habitats studied in this subarctic region of nitrogen, phosphate and mineral compounds. were found. Freshwater biodiversity in northern During warm and dry summer, the water gradu- Europe is low probably as a result of the short ally dries up, and concentrations of dissolved growing season of the aquatic plants, the lack inorganic and organic substances become pro- of adequate nutrients and hence the low primary gressively higher. The species that inhabit these production. Species with long life cycles cannot waterbodies must have the ability to tolerate successfully colonize these habitats, because the high nutrients concentration, wide temperature season is too short for them to complete their ranges, and hypoxic conditions. Before these Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 209 waterbodies finally dry up, specialist species lay Alm, G. C. 1914b: Beschreibung einiger neuen Ostracoden aus Schweden. — Zoologischer Anzeiger 43: 468–475. desiccation-resistant eggs and enter diapause. Alm, G. C. 1915: Monographie der schwedischen Süsswas- For many species, the optimal reproductive ser-Ostracoden nebst systematischen Besprechungen der strategy in temporary waters is parthenogenesis, Tribus Podocopa. — Zoologiska Bidrag fran Uppsala because even a single egg can be sufficient to 4: 1–248. ensure recolonisation of a waterbody when it re- Clarke, K. R. & Gorley, R. N. 2006: PRIMER v6: user manual/tutorial fills (Mezquitaet al. 2005). . — PRIMER-E, Plymouth. Clarke, K. R. & Warwick, R. M. 1998: A taxonomic distinct- The main interrelated problems facing ness index and its statistical properties. — Journal of aquatic organisms inhabiting peat-bogs are low Applied Ecology 35: 523–531. pH and lack of calcium ions (or the difficulty in Clarke, K. R. & Warwick, R. M. 2001: Changes in marine their uptake). Ubiquitous bog-mosses (Sphag- communities, an approach to statistical analysis and num spp.) not only acidify the water, but also interpretation. — PRIMER-E, Plymouth. Cooke, G. D., Lombardo, P. & Brant, C. 2001: Shallow decomposition of a dense mass of decaying moss and deep lakes: Determining successful management utilizes much of the dissolved oxygen in the options. — LakeLine 21: 42–46. water and all of it in the underlying peat. Only Ekman, S. 1908: Ostracoden aus den nordschwedischen Hoch- some specially adapted species can tolerate these gebirgen. — Naturwissenschaftliche Untersuchungen extreme conditions. des Sarekgebirges in Schwedisch-Lappland 4 (Zoologie): 169–198. In the lakes in Poland, typical diurnal oscilla- Ekman, S. 1914: Beiträge zur Kenntnis der schwedischen tions in O2 and CO2 concentrations and pH shift süsswasser-Ostracoden. — Zoologiska Bidrag från Upp- the balance between photosynthesis (increas- sala 3: 1–36. Fryer, G. 1993: The freshwater Crustacea of Yorkshire: a ing oxygen levels, reducing CO2 and increasing the alkalinity) and respiration (reducing oxygen faunistic and ecological survey. — Yorkshire Natu- ralists’ Union and Leeds Philosophical and Literary levels, increasing carbon dioxide concentrations Society. and hence reducing pH). When pH and oxygen Gerecke, R., Stoch, F., Meisch, C. & Schrankel, I. 2005: Die concentrations increase, ionic iron changes Fauna der Quellen und des hyporheischen Interstitials from soluble ferrous ions to insoluble ferric ions in Luxemburg. Unter besonderer Berucksichtigung der which tend to precipitate in the form of ferric Milben (Acari), Muschelkrebse (Ostracoda) und Ruder- fusskrebse (Copepoda). — Ferrantia 40: 1–134. hydroxide. As a result, iron was not detectable in Gifre, J., Quintana, X. D., Barrera, R., Martinoy, M. & the water column of the Polish lakes. The littoral Marquès, E. 2002: Ecological factors affecting ostracod zone of a lake supports a high species diversity distribution in lentic ecosystems in Empordà Wetlands and while there are specialized lake species, the (NE Spain). — Archiv für Hydrobiologie 154: 499–514. lakes are also inhabited by eurybiontic species. Håkanson, L. & Jansson, M. 2002: Principles of lake sedi- mentology. — The Blackburn Press, Caldwell, NJ. Heino, J. 2000: Lentic macroinvertebrate assemblage struc- ture along gradients in spatial heterogeneity, habitat size Acknowledgements and water chemistry. — Hydrobiologia 418: 229–242. Heino, J. 2002: Concordance of species richness patterns This work was supported by funds from the University of among multiple freshwater taxa: a regional perspective. Gdańsk (project no. BW-1411-5-0337-6) and by EU Marie — Biodiversity and Conservation 11: 137–147. Curie Research and Training Network (contract no. MRTN- Hiller, D. 1972: Untersuchungen zur Biologie und zur Ökolo- CT 2004-512492). Special thanks go to Geoff Boxshall and gie limnischer Ostracoden aus der Umgebung von Ham- Martin Angel for their valuable comments on the manuscript. burg. — Archiv für Hydrobiologie, Suppl. 40: 400–497. Holmes, J. A. & Chivas, A. R. (eds.) 2002: The Ostracoda: application in Quaternary research. — American Geo- physical Union, Washington DC. References Horne, D. J. 2004: Fauna Europaea: Ostracoda. — In: Boxshall, G. (ed.), Fauna Europaea: Crustacea. Fauna Akatova, N. A. & Järvekülg, A. A. [Akatova, N. A. & Europaea ver. 1.1, http://www.faunaeur.org. Ärvekul‘g, A. A.] 1965: [Ostracoda of the Karelian Horne, D. J., Cohen, A. & Martens, K. 2002: Taxonomy, lakes]. — In: [Fauna of the Karelian lakes]: 147–152. morphology and biology of Quaternary and living Ostra- Nauka, Moskva-Leningrad. [In Russian]. coda. — In: Holmes, J. A. & Chivas, A. R. (eds.), The Alm, G. C. 1914a: Beiträge zur Kenntnis der nördlichen Ostracoda: applications in Quaternary research: 5–36. und arktischen Ostracodenfauna. — Arkiv för Zoologi American Geophysical Union, Washington DC. 9: 1–20. Horne, D. J. & Martens, K. 1999: Geographical partheno- 210 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49

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Museum, Bergen Software for Canonical Community Ordination (version Silfverberg, H. 1999: A provisional list of Finnish Crustacea. 4.5). Microcomputer Power, Ithaca, NY. — Memoranda Societatis pro Fauna et Flora Fennica Tikkanen, M. 2005: Climate. — In: Seppälä, M. (ed.), The 75: 15–37. physical geography of Fennoscandia: 97–112. Oxford Søndegaard, M., Jeppesen, E. & Jensen, J. P. 2005: Pond or University Press, Oxford. lake: does it make any difference? — Archiv für Hydro- Vekhov, N. V. 2001: Crustaceans from rockpools of islands biologie 162: 143–165. and the shore of the Kandalaksha Bay of the White Stebel, K., Christensen, G. N., Derome, J. & Grekelä, I. Sea. — Inland Water Biology 3: 20–28. [In Russian with (eds.) 2007: State of the environment in Norwegian, English abstract]. Finnish and Russian border area. — The Finnish Envi- Viehberg, F. A. 2006: Freshwater ostracods assemblages ronment 6: 1–68. and their relationship to environmental variables in Sywula, T. 1965: Ostracoda of the National Park of Great water from northeast Germany. — Hydrobiologia 571: Poland. — Prace Monograficzne nad Przyrodą Wielko- 213–224. polskiego Parku Narodowego pod Poznaniem 5: 1–27. Wickins, J. F. 1984: The effect of reduced pH on carapace [In Polish with English abstract]. calcium, strontium and magnesium levels in rapidly Sywula, T. 1974: Małżoraczki (Ostracoda). — In: Wrób- growing prawns (Panaeus monodon Fabricius). — lewski, A. (ed.), Fauna Słodkowodna Polski 24: 1–315. Aquaculture 41: 49–60. Wydawnictwo Naukowe PWN, Warszawa/Poznań. Williams, D. D. 2006: The biology of temporary waters. — ter Braak, C. J. F. & Šmilauer, P. 1997–2009: CANOCO for Oxford University Press, New York. Windows 4.56. — Biometris, Plant Research Interna- Willig, M. R., Kaufman, D. M. & Stevens, R. D. 2003: Lati- tional, Wageningen. tudinal gradients of biodiversity: pattern, process, scale, ter Braak, C. J. F. & Šmilauer, P. 2002: CANOCO Reference and synthesis. — Annual Review of Ecology, Evolution Manual and CanoDraw for Windows User’s Guide: and Systematics 34: 27–309. 212 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49 (%) 50.6 92.2 50.5 86.4 81.0 85.0 88.5 87.4 84.0 88.6 74.3 86.7 92.9 85.3 85.3 85.4 81.5 84.1 85.9 80.8 84.1 50.0 89.5 87.7 Hydration 6.5 (%) 11.1 54.5 79.3 58.6 85.2 55.0 53.2 70.5 79.9 41.3 73.3 70.9 66.0 81.5 57.1 45.6 59.7 46.1 38.3 68.6 10.0 96.1 68.1 matter Organic )

–3 3– 4

0.125 0.125 0.250 0.250 0.250 0.250 0.250 0.125 0.250 0.500 0.250 0.250 0.250 0.250 0.125 0.250 0.250 0.125 0.125 0.250 0.125 0.250 0.250 0.250 PO (mg dm ) –3

– 3

0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 NO (mg dm ) –3

2+

10 40 10 20 10 40 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 (mg dm ) –3

1.00 0.00 0.05 0.50 0.00 0.05 0.20 1.00 0.30 0.80 0.80 0.00 0.00 1.50 0.05 0.60 0.40 0.00 0.20 2.00 0.00 0.80 0.00 1.50 Total Fe Total c a (mg dm

26.0 51.0 42.0 22.0 46.0 39.0 42.0 27.0 36.0 17.0 37.0 43.0 59.0 23.0 28.0 22.0 33.0 33.0 45.0 27.0 27.0 42.0 33.0 26.0 (cm) Transparency ) –1 66.6 79.5 60.8 44.9 53.4 63.1 56.3 95.7 94.2 39.9 87.7 57.5 92.9 115.6 135.5 282.0 177.3 109.8 104.5 104.5 126.7 106.0 150.1 105.8 (μS cm pH c onductivity 7.9 8.1 5.9 5.9 7.8 7.0 6.5 6.2 6.2 4.3 7.2 7.6 6.7 5.9 6.6 7.1 6.4 6.2 6.2 6.2 7.6 7.1 6.6 6.9 ) –3

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Salinity (g dm ) –3

7.11 8.65 7.58 5.53 7.42 7.51 5.33 4.85 4.27 5.51 5.72 8.48 7.93 7.13 3.12 6.20 6.38 6.55 7.64 5.26 5.05 7.61 6.18 6.68 Oxygen (mg dm (%) 62.8 80.6 85.5 57.1 54.4 44.9 59.7 70.6 90.3 80.2 68.5 68.2 25.4 55.0 53.9 67.1 76.2 51.6 51.7 76.3 73.7 72.5 76.1 108.1 Oxygen Physical and chemical properties of water bottom sediment (organic matter content hydration) for the studied sites in Lapland (L1–L24). 9.6 (° C ) 11.5 23.3 19.5 21.4 16.0 20.4 19.1 15.1 15.0 25.4 18.3 16.3 15.5 12.8 10.2 19.0 16.4 16.9 18.0 17.3 21.0 20.1 18.8 Temp.

Appendix 1. Site L1 L2 L3 L4 L5 L6 L7 L8 L9 L10 L11 L12 L13 L14 L15 L16 L17 L18 L19 L20 L21 L22 L23 L24 Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 213 (%) 88.6 33.3 90.7 94.8 91.4 47.1 54.0 39.7 72.9 87.8 31.4 33.9 69.5 56.8 61.1 49.9 38.7 61.6 49.9 93.7 83.2 49.9 49.9 37.3 61.2 Hydration 3.8 2.0 2.1 8.7 (%) 96.7 86.3 96.7 89.2 14.9 16.6 10.5 38.3 82.7 28.2 21.4 23.6 16.2 22.3 16.2 89.0 93.2 16.2 16.2 10.5 13.5 matter Organic )

–3 3– 4

0.125 0.125 0.250 0.250 0.500 0.250 0.125 1.500 0.125 0.125 0.500 0.250 0.250 5.000 5.000 0.500 0.500 0.250 1.500 0.125 0.000 5.000 0.250 0.000 PO 10.000 (mg dm ) –3

– 3

0.5 0.5 1.0 0.5 1.0 0.5 0.5 0.5 0.5 1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0 0.5 0.5 0.5 1.0 1.0 0.5 0.5 2.5 NO (mg dm ) –3

2+

20 40 20 10 20 10 80 40 40 80 40 60 40 20 10 10 80 60 160 220 120 140 140 160 180 (mg dm ) –3

1.00 0.00 2.00 0.10 0.20 2.00 0.40 2.00 0.00 0.00 0.00 0.00 0.00 2.00 0.70 2.00 2.00 1.10 0.10 2.00 2.00 0.40 2.00 0.05 0.05 Total Fe Total c a (mg dm

9.5 23.0 42.5 14.0 14.0 17.5 14.5 24.0 16.5 16.0 31.0 27.0 25.0 32.0 18.0 17.5 17.0 13.0 25.0 36.0 23.0 24.0 10.0 22.0 34.0 (cm) Transparency ) –1 44.9 54.3 19.1 89.6 64.3 37.0 40.8 196.1 264.0 416.0 801.0 295.0 179.4 384.0 301.0 274.0 863.0 288.0 649.0 426.0 1127.0 1617.0 4500.0 1658.0 2920.0 (μS cm pH c onductivity 4.2 7.2 5.0 4.5 6.9 5.3 8.1 7.7 8.9 7.6 8.7 7.8 8.3 7.4 7.4 7.7 7.9 7.9 8.0 7.0 4.7 5.3 7.8 7.6 8.8 ) –3

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.1 0.0 0.0 0.1 0.0 0.6 0.2 2.4 0.8 1.5 0.0 0.0 0.0 0.0 0.5 0.1 0.0 Salinity (g dm ) –3

5.02 2.95 2.03 4.92 1.44 1.26 8.50 3.40 9.71 5.90 4.60 3.23 6.81 3.70 9.30 8.51 9.85 6.60 5.87 1.97 11.13 11.00 13.30 13.02 12.84 Oxygen (mg dm (%) 11.9 52.9 32.4 21.7 54.4 13.8 37.0 69.8 52.0 32.3 72.2 42.0 89.2 63.2 63.6 21.7 111.6 101.0 107.0 123.2 127.7 101.7 131.5 131.5 121.3 Oxygen Physical and chemical properties of water bottom sediment (organic matter content hydration) for the studied sites in Poland (P1–P25). (° C ) 15.4 20.2 17.1 19.7 12.8 17.3 21.0 16.8 22.3 21.5 20.2 18.8 18.9 19.0 20.3 18.7 22.2 12.1 13.3 19.9 17.6 10.8 14.8 15.2 19.2 Temp.

Site P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 Appendix 2. P15 P16 P17 P21 P22 P23 P24 P25 P18 P19 P20

214 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49 Percentage 0.2 4.8 3.1 1.6 0.6 1.3 0.3 9.1 0.1 0.2 0.4 1.6 0.1 0.2 0.3 1.7 0.3 0.2 0.3 1.7 < 0.1 6 66 66 64 86 607 462 246 163 630 132 106 678 228 124 109 3868 2514 1030 7314 1392 ( D ), percent - 2 3 66 33 64 43 66 62

114 607 231 515 123 163 630 106 678 109 696

1934 1257 3657 11157

ypridinae indet. ypridinae C

4 2j 2j

sp. juv. sp. Pseudocandona

4j 1j 2j 1j 4j 3 j

11j 86j 16j 15j 17j 388 228j

stagnalis

Pseudocandona 7 7a

rostrata Pseudocandona 6j 1j 1j 4j 1j 2j

7a 1a 1a 1a 5a 9a 90j 17j 18j 18j

11a 98a 34a 12a 25a 642 22a 18a 101j 139a

albicans Pseudocandona

1 1a

lapponica Fabaeformiscandona

2j

13 11a

sp. Eucypris

1 1j Eucypris pigra Eucypris

4 4a

fasciata Dolerocypris

1j

1a 2a 31 17a 10a Cypridopsis vidua Cypridopsis 4j 2j

1a 5a 1a 7a

17a 19a 278 82a 140a Cypria ophtalmica Cypria

5j

3a 43 3a 32a

serena Cyclocypris

4a 8a 4a 1a 18 1a

juv. vidua C.

+ ovum C.

1352 1352j Cyclocypris ovum Cyclocypris 7j 3j 8j 1j 3a 45 64j

81a 64a 41a 17a 60a 48a 778j

112a 4914 526a 637a

1213a 1206a

globosa Cyclocypris

2a 1a 28 25j

vavrai Cryptocandona

11 9a 1a 1a

reducta Cryptocandona

6j 10 4a

(early stages) (early C. candida C.

5j 2j 1j 3j 1j

23j 26j 292 231j Candona candida Candona 9j 2j 3j 1j 3j 9a

1a 8a 2a 4a 86j 26j 65j 12j 39j 68j 23j Abundances of particular species/taxa in the samples from the studied sites in Lapland (L1–L24), total sample abundance ( N ), density per m 38a 10a 51a 19a 13a 28a 27a

314j 101j 274j 287j 164a 106a 2857 1064j

reticulata Bradleystrandesia 2

1a 1a 21j

28a 39a 263 58a 10a 103a Site age of the total sample abundance in the overall number of the collected ostracods from both regions (%), and total absolute abundance of taxa in all samples taken in (a = adults, j juveniles). Lapland (Total) L19 Appendix 3. L1 L18 L2

L3 L20

L4 L6 L22 L21

L24

Total L8 L7 L9

L11 L13 L12

L14

L16 L15 L17

Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 215 0.2 4.8 3.1 1.6 0.6 1.3 0.3 9.1 0.2 0.4 0.1 1.6 0.1 0.2 0.3 1.7 0.3 0.2 0.3 1.7 < 0.1 6 66 64 66 86 607 462 246 163 630 132 106 678 228 124 109 3868 2514 1030 7314 1392 ( D ), percent - 2 3 66 64 33 43 66 62 114 607 231 515 123 163 630 106 678 109 696 1934 1257 3657 11157 4 2j 2j 4j 1j 2j 1j 4j 3 j 11j 86j 16j 15j 17j 388 228j 7 7a 6j 1j 1j 4j 1j 2j 7a 1a 1a 1a 5a 9a 90j 17j 18j 18j 11a 98a 34a 12a 25a 642 22a 18a 101j 139a 1 1a 2j 13 11a 1 1j 4 4a 1j 1a 2a 31 17a 10a 4j 2j 1a 5a 1a 7a 17a 19a 278 82a 140a 5j 3a 43 3a 32a 4a 8a 4a 1a 18 1a 1352 1352j 7j 3j 8j 1j 3a 45 64j 81a 64a 41a 17a 60a 48a 778j 112a 526a 4914 637a 1213a 1206a 2a 1a 28 25j 11 9a 1a 1a 6j 10 4a 5j 2j 1j 3j 1j 23j 26j 292 231j 9j 2j 3j 1j 3j 9a 1a 8a 2a 4a 86j 26j 65j 12j 39j 68j 23j Abundances of particular species/taxa in the samples from the studied sites in Lapland (L1–L24), total sample abundance ( N ), density per m 38a 10a 51a 19a 13a 28a 27a 314j 101j 274j 287j 164a 106a 2857 1064j 2 1a 1a 21j 28a 39a 58a 263 10a 103a age of the total sample abundance in the overall number of the collected ostracods from both regions (%), and total absolute abundance of taxa in all samples taken in (a = adults, j juveniles). Lapland (Total) L1 L19 Appendix 3. L18 L2

L3 L20

L4 L6 L22 L21

L24

L8 L7 Total L9

L11 L13 L12

L14

L16 L15 L17

216 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49 Cyprois marginata Cyprois 15 ( D ), percent - 2 121

14a/1j 52a/69j Cypris pubera Cypris

128 391j 4425 29a/4j

93a/35j

278a/14j 5a/1383j 148a/59j 129a/329j 42a/1614j Cypridopsis vidua Cypridopsis 1j 1j 8a 5a 300 724 1a/1j 6a/1j 124a

11a/9j 89a/2j 59a/6j 17a/2j

206a/5j 17a/25j 18a/410j C. ophtalmica C. 6 1a 2a 9a 3a 1a 1a 37a 12a 38a 5206 11a/1j

5064a/32j Cypria exsculpta Cypria 1 2

1a

1a/1j C. ovum C. 1 1a 44a 24a 598

9a/2j 219a 154a

143a/3j C. laevis C. 1a 3a 1a 12 3089 543a 11a/1j 320a/4j

336a/12j 171a/12j

1584a/102j Cyclocypris globosa Cyclocypris 7j 1a 20 13j 1117

612a/504j Candonopsis kingsleii Candonopsis 1a 2a 8a 20j 11a 758 263

21a/6j 8a/55j

22a/14j 8a/194j 18a/21j 16a/596j

sp. Candona

32 39j 21j 14j 55j 17j 18j 14a 146 C. weltneri C. 3a 18a 17a 395 32a 464 14a/9j 2a/80j 6a/21j 215a/9j 146a/1j 118a/168j

Candona candida Candona 7j 4j 2j 2j 62 56a 81a 370

233a

1a/16j 14a/16j B. reticulata B. 4 2a 1a 2a/1j 7a/5j 5865 571a 4a/1191j 1931a/4 j

293a/1857j

Abundances of particular species/taxa in the samples from the studied sites in Poland (P2–P25), total sample abundance ( N ), density per m fuscata C ontinued. Bradleystrandesia 1j 1a 1a 4a 30 725

5a/3j

13a/2j 721a/4j Site P6 P4 P5 P7 ages of the total sample abundance in the overall number of the collected ostracods from both regions (%), and total abundance of taxa in all (a = adults, j juveniles). samples taken in (Total) Poland P8 P9 Appendix 4. P2 Appendix 4. P2 P5 P8 P9 P10 P10 P13 P11 P12 P13 P11 P12 P15 P16 P17 P19 P20 P22 Total P14 P20 P22 P24 P25 P14 P23 P24 P25 Total P16 P19 P15

Ann. Zool. Fennici Vol. 49 • Ostracods ecology of subarctic and temperate Europe 217 Paracandona euplectella Paracandona 15 ( D ), percent - 2 121

14a/1j 52a/69j Notodromas monacha Notodromas

128 391j 4425 29a/4j

93a/35j

278a/14j 5a/1383j 148a/59j 129a/329j 42a/1614j Metacypris cordata Metacypris 1j 1j 8a 5a 300 724 1a/1j 6a/1j 124a

11a/9j 59a/6j 89a/2j 17a/2j

206a/5j 17a/25j 18a/410j Limnocythere inopinata Limnocythere 6 1a 2a 3a 9a 1a 1a 37a 12a 38a 5206 11a/1j

5064a/32j I. gibba I. 1 2

1a

1a/1j Ilyocypris decipiens Ilyocypris 1 1a 44a 24a 598

9a/2j 219a 154a

143a/3j Heterocypris incongruens Heterocypris 1a 3a 1a 12 3089 543a 11a/1j 320a/4j

336a/12j 171a/12j

1584a/102j

sp. juv. sp. Fabaeformiscandona 7j 1a 20 13j 1117

612a/504j F. hyalina F. 1a 2a 8a 20j 11a 758 263

21a/6j 8a/55j

22a/14j 8a/194j 18a/21j 16a/596j

fabaeformis Fabaeformiscandona

32 21j 39j 14j 55j 17j 18j 14a 146 E. virens E. 3a 18a 17a 395 32a 464 14a/9j 2a/80j 6a/21j 215a/9j 146a/1j 118a/168j

Eucypris crassa Eucypris 4j 7j 2j 2j 62 56a 81a 370

233a

1a/16j 14a/16j Dolerocypris fasciata Dolerocypris 4 2a 1a 2a/1j 7a/5j 5865 571a

4a/1191j 1931a/4 j

293a/1857j Abundances of particular species/taxa in the samples from the studied sites in Poland (P2–P25), total sample abundance ( N ), density per m stevensoni Darwinula C ontinued. 1j 1a 1a 4a 30 725

5a/3j

13a/2j 721a/4j Site ages of the total sample abundance in the overall number of the collected ostracods from both regions (%), and total abundance of taxa in all (a = adults, j juveniles). samples taken in (Total) Poland P2 P4 P5 P6 P7 Appendix 4. Appendix 4. P2 P5 P8 P9 P10 P8 P9 P11 P12 P13 P10 P13 P15 P16 P17 P19 P20 P22 Total P11 P12 P14 P20 P22 P24 P25 P14 P23 P24 P25 Total P16 P19 P15

218 Iglikowska & Namiotko • Ann. ZOOL. Fennici Vol. 49 Percentage 1.6 0.5 2.7 5.9 0.4 1.7 3.8 0.9 5.4 6.6 0.5 2.6 6.1 2.8 5.8 0.6 7.7 1.4 2 .0 13.2 < 0.1 < 0.1 2 1 275 165 704 367 402 904 739 4117 1322 2200 1536 6543 2056 4922 6043 9404 8629 21260 19008 21424 1 1 661 206 165 704 367 201 226 554 809

1100 1134 5315 2376 1536 2181 2678 1028 2461 2351 3088

29143 Tonnacypris lutaria Tonnacypris

6a 1a 2a 52 33a 10a

sp. juv. sp. Pseudocandona 1j 4j 1j 2j 1j

42j 32j 10j 19j 56j

219j 244j 727j 441j 1799 P. sucki P.

3a

17a 171 151a P. stagnalis P. 1a 231 12a

10a/2j 199a/7j

rostrata gr. ex P.

1j 8j 4j

13j 60j 331 245j P. pratensis P.

72a 74a 318 12a

117a 41a/2j P. marchica P.

68 27a 31a 10a P. insculpta P. 4a

166 59a 48a

2a/4j 47a/2j P. hartwigi P.

51 8a 28a 15a

compressa gr. ex P.

4j 5j

10j 97j 17j 133 P. compressa P. 941 16a 14a 152a

648a/111j C ontinued. albicans Pseudocandona

3 3a Site Total P25 P24 P23 P22 P19 P20 P17 P16 P15 P9 P14 P11 P10 P7 P8 P6 P13 P12 P3 P4 P5 Appendix 4. P2

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