Morphological Differentiation of Some Populations of the Genus Cyclops (Copepoda: Cyclopoida) from Bohemia (Czech Republic)

Acta Soc. Zool. Bohem. 66: 161–168, 2002 ISSN 1211-376X

Morphological differentiation of some populations of the genus Cyclops (Copepoda: Cyclopoida) from Bohemia (Czech Republic)

Zdeněk BRANDL & Markéta LAVICKÁ*)

Faculty of Biological Sciences, University of South Bohemia, Branišovská 31, CZ–370 05 České Budějovice, Czech Republic; e-mail: [email protected]

Received June 3, 2002; accepted September 3, 2002 Published November 4, 2002

Abstract. Groups of spines forming the coxal ornamentation of the fourth pair of swimming legs and some other morphological details are used to distinguish species of the genus Cyclops O. F. Müller, 1776, from several habitats in the Czech Republic. The identity of populations based on these characters agrees with that derived from allozyme analyses. Besides the easily distinguished species Cyclops vicinus Uljanin, 1857 and C. insignis Claus, 1857, three other species were found: C. furcifer Claus, 1857 (in temporary waters) and probably C. strenuus Fischer, 1851 and C. abyssorum G. O. Sars, 1863 (in permanent waters). Morphology, cryptic species, coxal ornamentation, species identification, habitats, Cyclops, Czech Republic, Palaearctic region

INTRODUCTION Although the detailed taxonomic differentiation of the common species of cladocerans in this country has long tradition (e.g., Kurz 1874) and was greatly enhanced by Hrbáček in his early publications (1959a, b), common cyclopoid copepods were believed to be a well-known group of simply delimited species with good differentiating morphological characters (Šrámek-Hušek 1938, 1953). Even the most common limnetic genus Cyclops O. F. Müller, 1776, was supposed to be represented by just two limnetic species, C. strenuus Fischer, 1851, and C. vicinus Uljanin, 1857, and two others inhabiting rather small water bodies (C. insignis Claus, 1857, and C. furcifer Claus, 1857). The fifth species listed in the Bohemian faunistic records was originally described by Šrámek-Hušek (1937) as C. bohemicus Šrámek-Hušek, 1937, from the lake Černé Jezero in the Šumava Mountains and later assigned to the complex of C. abyssorum Sars, 1863. Now it is supposed to be extinct at the original type locality. On the other hand, the parts of Europe rich in numerous and deep lakes (both northern Europe and the subalpine countries) are known to have a higher number of closely related and morphologically very similar limnetic species of the genus Cyclops (e. g., C. scutifer Sars, 1863, C. abyssorum, C. lacustris Sars, 1863, C. kolensis Lilljeborg, 1901, C. bohater Kozminski, 1933). Their species identity and mutual relationships were quite complicated and unclear. Kozminski (1936) introduced a detailed and elaborate morphometric analysis using about 30 statistically evaluated characters to distinguish closely related species. Even using this approach the specific identity of some populations remained uncertain (Einsle 1975). Their differentiation was enabled by two new techniques

*) Present address: Department of Parasitology and Hydrobiology, Charles University, Viničná 7, CZ–128 44 Praha 2, Czech Republic This contribution is dedicated to Doc. RNDr. Jaroslav Hrbáček, DrSc., upon the occasion of the 80th anniversary of his birthday (12th May 1921).

161 introduced only a quarter of century ago. Beermann (1977) discovered the partial elimination of chromatine from the chromosomes of early embryonic cells of a cleaving egg. The timing of this process into the exact phase of the egg cleveage, specific for each of the very closely related species, allowed Einsle (e.g., 1996a, b) to identify and describe some of the so far unrecognized species. He also used another technique, i.e. the electrophoretic separation of allozyme (for copepods used earlier by Boileau and Hebert 1988) to distinguish such very similar species. Combining these two approaches with the analysis of previously neglected details of morphological structures (Einsle 1985), he was better able to delimite the existing species and to describe some new species (C. heberti Einsle, 1996, C. singularis Einsle, 1996, and C. stagnalis Einsle, 1996). The aim of this work is to describe some detailed morphologic characters of several Bohemian populations of the genus Cyclops which we have collected and to compare their species identity with the recentmost descriptions.

MATERIAL AND METHODS

Plankton samples were collected with a coarse plankton net (0.38 mm mesh size) either by vertical hauls from deep reservoirs and ponds or by pouring water gathered by 1-litre wide-mouth bottle from shallow pools through the net. If possible, adult females were individually selected immediately from the fresh live material and then preserved in 4% formalin; otherwise the whole sample was preserved in the same way. Preserved animals were dissected in a drop of glycerin on a microscopic glass. The 4th pair of swimming legs and its posterior face ornamentation were examined. The ornamentation of the coxal segment of the basipodite of this pair of legs consists of up to seven groups (Fig. 1, A to F) of little spines or setulae. They are arranged and placed in characteristic positions (Einsle, 1996b) on the coxal segment. Moreover, the praecoxal plate connecting the coxae (intercoxal coupler) may be either nake or covered with setulae and either simply even at the distal margin or humped on each side near the inner lateral seta of the coxa (Fig. 1, H – the letter symbols follow Einsle, 1996b). The humps may either be short and not exceeding the margin of the plate or they may project significantly

Fig. 1. Ornamentation pattern of the coxal segment of the 4th pair of swimming legs in Cyclops O. F. Müller: general scheme. The letters follow conventional labelling by Einsle (1985). A to F: groups of spines or setulae; H: the humps of the intercoxal coupler.

162 beyond the coupler margin. Other characters which we have recorded were the length of antennules as compared with the length of the cephalothoracic body region, the shape of the genital segment of females, the position of the lateral spine at the inner side of the distal segment of the 5th legs, and the length of apical spines of the last segment of endopodite of the 4th pair of swimming legs. We collected and examined material from various types of habitats ranging from deep reservoirs (Slapy Reservoir on the Vltava River in Central Bohemia, Římov Reservoir on the Malše River in South Bohemia) to ephemeral puddles filled with rain water. Small permanent waters were represented by carp ponds and also by permanent pools in the innundation areas of the Labe (Elbe) River nr. Velký Osek (north of Kolín, Central Bohemia) and of the Upper Lužnice River (south of Suchdol nad Lužnicí). Besides these materials collected for the purpose of this work, we also examined some of our older collections or samples kindly supplied by colleagues.

RESULTS The specimens of cyclopoid copepods of the genus Cyclops we have examined can be distinguished into five morphologically different types. The first of these types, which can be easily recognized, is represented by C. insignis, the species differring from all the others within the genus Cyclops by its 14-segmented antennules when adult. Adults of all the other species of this genus have 17-segmented antennules, with a characteristic group of four short segments, which are just as long as they are wide, in the middle of the antennule (segments 8 through 11). One of the other four types we collected is undoubtedly a common species C. vicinus. The typical characters of C. vicinus are the “wings”, i.e. widely extended lateral lobes of the 4th thoracomer, together with another constant character of this species, the spine formula 2.3.3.3. The last character may occur in some of the other Cyclops species which otherwise have the spine formula 3.4.3.3. Therefore we describe some details of C. vicinus morphology in comparison to the details of the remaining three types. The ornamentation of the coxal segment of the basipodite of the 4th pair of swimming legs and the ornamentation of the intercoxal plate of this pair of legs (the coupler) Cyclops vicinus. (Ornamentation pattern ABCDEF, Fig. 2). Group A consists of 20–35 mostly small spines in a few rows. Some spines may be longer than the others. Group B: 4–7 short thick spines. Group C: 7–12 long thick spines of equal length. Group D: 1 or 2 short thick spines. Group E: numerous thin spines covering each other. Group F: short fine setae along the distal half of the outer coxal edge. Intercoxal coupler: naked, with a pair of little humps. Type I (Ornamentation pattern ACD, Fig. 2). Group A consists of 18–25 spines, the half of them close to the coupler being finer, longer and set into slightly bent arch, the external half of them being shorter, especially those in the middle of the row. Group C: 3–5 thicker and longer spines, slightly bent outward from the intercoxal coupler. Group D: 1–3 short and thick spines. The humps on the intercoxal coupler do not extend beyond the coupler margin, the coupler bears one row of fine long setae in the middle of its length. Groups B, E, F: missing. Type II (Ornamentation pattern ACDE, Fig. 2). Group A: 15–23 thick spines shorter than in type I, often placed on the cuticular lobe. Group C: 6–8 thick spines, those in the middle being longer than the external ones. Group D: 2–5 thick long spines. Group E: large number (up to more than 10) of short or long thin spines partially covering each other. The intercoxal coupler with a pair of humps extending well beyond its distal edge; the humps and the area between them are covered with a row of very long fine setae. Groups B, F: missing. Type III (Ornamentation pattern ABC, Fig. 2). Group A: a row of 25–30 short minute spines, with the internal half of the row often in two parallel curved lines. Group B: from 3 up to 7 or 10 long weak spines. Group C: long row of 14 to 22 short and strong spines of equal length. Intercoxal coupler: without any extending hump, covered with numerous fine long setae in its distal part. Groups D, E, F: missing.

163 Position of the lateral spine of the 2nd segment of the 5th leg Cyclops vicinus: inserted at the middle of the segment, not longer than the segment itself. Type I : at the middle of the segment, as long as the segment. Type II: at the middle of a very long and slender segment, shorter than the segment. Type III: the spine shifted to the distal end of a shorter and wider segment.

Fig. 2. Ornamentation pattern of the coxal segment of the 4th pair of swimming legs found in the examined populations: CV = Cyclops vicinus Uljanin, 1857, 1 to 3 = Types I to III.

164 The length of the outer apical spine of the 4th endopodite Cyclops vicinus: one third of the length of the inner apical spine. Type I: 1/3 to 1/2 of the length of the inner apical spine. Type II: 1/2 to 2/3 of the length of the inner apical spine. Type III: 1/3 of the length of the inner apical spine. Shape of the genital segment of female Cyclops vicinus, Type I, Type II: Broadest at anterior part and gradually narrowing at posterior part. Type III: Anterior part wide, round-shaped, then abruptly narrowing into a cylindrical caudal part. Habitats and localities Cyclops insignis. Spring species in small permanent waters. Two permanent backwaters, Upper Lužnice River nr. Dvory nad Lužnicí, many samples from 1992–1994, J. Hrbáček legit; the same backwaters, 8.3. 1995, 21.3. 1995, Holý (1996); extensive flat shoal overgrown with willow and alder shrub, Starý Vrbenský Pond nr. České Budějovice, 28.3. 1996, 11.4. 1996, 26.3. 1997, 9.4. 1997, M. Lavická legit. Cyclops vicinus. The most frequent species of the genus Cyclops in Bohemian ponds, reservoirs and permanent backwaters. Almost permanent inhabitant of limnetic region with maximum density in spring when its copepodid larvae emerge from the cocoons diapausing on the bottom. Examples of localities: Slapy Reservoir, Římov Reservoir (Brandl 1994); ponds nr. Blatná (Kořínek et al. 1987); ponds Starý Vrbenský, Nový Vrbenský, Starý Haklovský, Nový Haklovský nr. České Budějovice, year-round collections 1992, 1993, Z. Brandl legit; permanent backwater, Upper Lužnice River nr. Lesní Chalupy, 27. 4. 1999, M. Lavická legit; permanent backwater, Labe (Elbe) River nr. Velký Osek, 22. 4. 1999, M. Lavická legit. Populations of the Type I. Permanent backwater, Upper Lužnice River nr. Lesní Chalupy, 27. 4. 1999; permanent backwater, Labe (Elbe) River nr. Velký Osek, 22. 4. 1999; Starý Vrbenský Pond nr. České Budějovice, 5. 5. 1999; Římov Reservoir, 2. 6. 1999, all M. Lavická gblegit. Populations of the Type II. Permanent backwater, Upper Lužnice River nr. Lesní Chalupy, 27. 4. 1999; Římov Reservoir, 2. 6. 1999, all M. Lavická legit; Slapy Reservoir, material cultivated from the female collected on 6. 3. 1999 by J. Hrbáček. Populations of the Type III. Ephemeral pool filled only by rain water, with maximum depth of 0.07 m, grassland and shrubs at the abandoned millitary training area, NW edge of the town České Budějovice, 27. 5. 1999, M. Lavická legit. The identity of Types I to III When the ornamentation patterns and the other details described above are compared with the most recent descriptions of such characters given by Einsle (1996a, 1996b) we can state that: Type I fits best to the description of these characters of either C. strenuus or C. stagnalis Type II is closest to the description of the lowland populations (“C. divulsus” group) of C. abyssorum or to the description of C. singularis Type III is less ambiguous being closely similar to the description of C. furcifer with uniform spine formula 3.4.3.3 (the rarer of the two possible formulas of this species).

DISCUSSION All five Cyclops species mentioned in the previous paragraph may occur in Bohemian water bodies. All these species are very similar in their morphology and differ in very small and unstable details. Einsle (1996b) uses the point of insertion of the lateral spine on the 2nd article of the 5th legs

165 (at the middle or nearer to the basis of the article). This character is very uneasy to quantify. Another character separating C. strenuus from C. stagnalis is the length of the antennules. Acord- ing to Einsle (1996b), they reach just the end of the cephalothorax in C. stagnalis but up to the middle of the 3rd thoracomer in C. strenuus. This character was found to be very variable at least in our populations by Lavická (2000). Similarly, the width of the 4th thoracomer is used to differentiate C. strenuus from C. abyssorum (e. g. Einsle 1975), the maximum width of this segment being in the middle of its length in C. strenuus but in the slightly extended corners of the posterior part in C. abyssorum. However, evaluation of this character is not always easy especially in preserved material. Thus the morphological characters do not offer a reliable way to identify a given population up to the species level. Another differentiation can be made using the stage of the egg cleavage in which redundant heterochromatin is eliminated. This “chromatin diminution” takes place in a definite cleavage stage specific for individual species which might differ also in the amount of such eliminated material (from small particles up to huge amount of heterochromatin, Beermann, 1966, Einsle, 1996b). The timing of diminution into the 4th or the 5th cleavage stage also separates the species in the two couples (C. strenuus + C. stagnalis and C. abyssorum + C. singularis) each of which has the same coxal ornamentation in both species of a couple. The procedure to find out this stage is relatively simple but hundreds to thousands individuals have to be examined until the eggs are found in the relevant stage of their embryonic development. Therefore we lack this information for any of the examined populations having the ornamentation of Types I, II or III. However, the relevant five species differ from each other in their habitats. Three of them, C. furcifer, C. stagnalis and C. singularis are known to dwell in the ephemeral habitats of temporary ponds and pools which often completely dry off. On the other hand, both C. strenuus and C. abyssorum (including its lowland group of populations known as the “C. divulsus-group”) are inhabitants of permanent waters ranging from small permanent ponds to large and deep lakes, although C. strenuus can be found in temporary pools, too. At least the populations of the Types I and II we examined came from permanent waters which included even two large reservoirs. The reservoir populations should therefore represent C. strenuus rather than C. stagnalis (Type I, Římov Reservoir) and C. abyssorum (Type II, Slapy Reservoir and Římov Reservoir) rather than C. singularis. The question of species identity of the populations which belong to the type having the same coxal ornamentation pattern was elucidated by parallel allozyme examination of the same populations by Lavická (2000). She applied the electrophoretic separation of enzymes arginine phos- phokinase (APK) and glutamateoxaloacetate transferase (GOT) made on the cellulose-acetate plates to all the populations of Type I, II and III we collected. With two loci of the GOT and three of APK enzymes she was able to distinguish three genetic types within the examined material. (The fourth one was represented by populations of Cyclops vicinus.) The most important result is that each of these three genetic types corresponded to one of the above described types of coxal ornamentation patterns. Thus, the populations having the same type of coxal ornamentation represent also one genetically uniform type – and therefore they belong to one species. When we take into account the properties of habitats of the Types I and II, they are most probably identical with C. strenuus and C. abyssorum (lowland “C. divulsus-group” of populations), respectively. The third Type III may represent an isolated local population of C. furcifer with stabilized spine formula 3.4.3.3, which otherwise is the less common of the two possible formulas of this species (Einsle 1996b). The occurrence of other species of the genus Cyclops, e.g. C. stagnalis, C. singularis or even C. heberti Einsle, 1996, and C. bohater Kozminski, 1933, is still possible in the Czech Republic. A population of the mountain subalpine type of C. abyssorum (“C. praealpinus-group”) lived in the

166 past in the Šumava Mountains’ lake “Černé jezero” (“C. bohemicus” of Šrámek-Hušek, 1937). In more recent years it was found in another of the Šumava Mountains’ lakes, the “Prášilské jezero” (e.g. Fott et al. 1994). Its relation to the lowland populations of C. abyssorum should be re- examined. Numerous populations of C. abyssorum inhabit mountain lakes in neighbouring Austria and Slovakia. Further reasearch of the genus Cyclops and its distribution in this country is still needed and should be preferably made using all three possible approaches: detail examination of morphology, enzyme electrophoresis and the analysis of chromatine diminution.

A c k n o w l e d g e m e n t s We are honoured to be invited to participate in this special issue dedicated to Doc. Jaroslav Hrbáček on the occassion of his 80th birthday. The first author is especially happy to do so with a paper on the detail morphology used to identify species – the approach which J. Hrbáček always promoted and taught his students. The study was supported by the grant F0149/1999(G4) of the Ministry of Education, Youth, and Sports. J. Hrbáček kindly supplied some samples of copepods. C. M. Steer greatly improved the English of this paper.

REFERENCES

BEERMANN S. 1977: The diminution of heterochromatic chromosomal segments in Cyclops (Crustacea, Copepoda). Chromosoma 60: 297–344. BOILEAU M. G. & HEBERT P. D. N. 1988: Electrophoretic characterization of two closely related species of Leptodiaptomus. Bioch. Syst. Ecol. 16: 329–332. BRANDL Z. 1994: The seasonal dynamics of zooplankton biomass in two Czech reservoirs: a long-term study. Arch. Hydrobiol. Beih. Ergebn. Limnol. 40: 127–135. EINSLE U. 1975: Revision der Gattung Cyclops s. str., speziell der abyssorum-Gruppe. Mem. Ist. Ital. Idrobiol. 32: 57–219. EINSLE U. 1985: A further criterion for identification of species in the genus Cyclops s. str. (Copepoda, Cyclopoida). Crustaceana 49: 299–309. EINSLE U. 1996a: Cyclops heberti n. sp. and Cyclops singularis n. sp., two new species within the genus Cyclops (‘strenuus-subgroup’) (Crust. Copepoda) from ephemeral ponds in southern Germany. Hydrobiologia 319: 167–177. EINSLE U. 1996b: Copepoda: Cyclopoida. Genera Cyclops, Megacyclops, Acanthocyclops. Guides to the Identification of the Macroinvertebrates of the Continental Waters of the World Vol. 10. Amsterdam: SPB Academic Publishing, 82 pp. FOTT J., PRAŽÁKOVÁ M., STUCHLÍK E. & STUCHLÍKOVÁ Z. 1994: Acidification of lakes in Šumava (Bohemia) and in the High Tatra Mountains (Slovakia). Hydrobiologia 274 (Developments in Hydrobiology 93): 37–47. HOLÝ M. 1996: Jarní zooplankton tůní v inundačním území horní Lužnice [Spring zooplankton of pools in the innundation area of the Upper Lužnice River]. Unpubl. M.Sc. Thesis, České Budějovice: Faculty of Biological Sciences, University of South Bohemia, 40 pp (in Czech). HRBÁČEK J. 1959a: Über die angebliche Variabilität von Daphnia pulex. Zool. Anz. 162: 116–126. HRBÁČEK J. 1959b: [On apparent variability of the cladoceran Daphnia pulex L.] Čas. Nár. Mus. v Praze, Odd. Přír. 128: 9–16 (in Czech). KOŘÍNEK V. , F OTT J., FUKSA J., LELLÁK J. & PRAŽÁKOVÁ M. 1987: Carp ponds of Central Europe. Pp.: 29–62. In: MICHAEL R.G. (ed.): Managed aquatic ecosystems. Amsterdam: Elsevier, 300 pp. KOZMINSKI Z. 1936: Morphologische und ökologische Utersuchungen an Cyclopiden der strenuus-Gruppe. Int. Rev. Ges. Hydrobiol. Hydrogr. 33: 161–240. KURZ W. 1874: Dodekas neuer Cladoceren nebst einer kurzen Übersicht der Cladocerenfauna Böhmens. Sitzungsber. K. & K. Akad. Wissensch. Wien, Math. Naturwissensch. Classe 68: 7–88. LAVICKÁ M. 1997: Jarní aspekt výskytu buchanek (Cyclopidae) v periodických tůních [Spring aspect of occurrence of cyclopoid copepods (Cyclopidae) in temporary pools]. Unpubl. B. Sc. Thesis, České Budějovice: Faculty of Biological Sciences, University of South Bohemia, 28 pp (in Czech). LAVICKÁ M. 2000: Genetická a morfologická charakteristika buchanek ze skupiny Cyclops strenuus (Crustacea, Copepoda) z periodických i permanentních vod v Čechách [Genetic and morphological characteristics of cyclopoid copepods from the group of Cyclops strenuus (Crustacea, Copepoda) from temporary and permanent waters in Bohemia]. Unpubl. M. Sc. Thesis, České Budějovice: Faculty of Biological Sciences, University of South Bohemia, 52 pp (in Czech).

167 ŠRÁMEK-HUŠEK R. 1937: [To the revision of cladocerans and cyclopoid copepods of the lake Černé Jezero in the Šumava Mountains]. Věda Přír. 18: 259–263 (in Czech). ŠRÁMEK-HUŠEK R. 1938: [Key to cyclopoid copepods of the family Cyclopidae]. Čas. Nár. Mus. v Praze, Odd. Přír. 112: 252–278 (in Czech). ŠRÁMEK-HUŠEK R. 1953: Naši klanonožci [Our copepods]. Praha: Nakl. Československé Akademie věd, 63 pp (in Czech).

168 Acta Soc. Zool. Bohem. 66: 169–175, 2002 ISSN 1211-376X

Impact of predation by cyclopoid copepods (Copepoda: Cyclopoida) on zooplankton in a carp pond in Czech Republic

Zdeněk BRANDL1) & Miroslava PRAŽÁKOVÁ2)

1) Hydrobiological Institute, Academy of Sciences, Czech Republic and Faculty of Biological Sciences, Univer- sity of South Bohemia, Branišovská 31, CZ–370 05 České Budějovice, Czech Republic; e-mail: [email protected] 2) Department of Parasitology and Hydrobiology, Charles University, Viničná 7, CZ–128 44 Praha 2, Czech Republic

Received June 3, 2002; accepted September 3, 2002 Published November 4, 2002

Abstract. Predation by cyclopoid copepods (Cyclops vicinus Uljanin, 1857, Acanthocyclops robustus (G. O. Sars, 1863), C. strenuus Fischer, 1851) was measured in field experiments in the pond Velký Pálenec (SW Bohemia, Czech Republic) during two consecutive years. The cyclopoid copepods fed on all common species of rotifers and also on the young larvae of copepods and in some periods also on Daphnia spp. and other cladocerans. The predatory impact of cyclopoid copepod feeding may influence considerably the populations of other zooplankters. Predatory feeding, impact of predation, Cyclops vicinus, Acanthocyclops robustus, rotifers, Czech Republic, Palaearctic region

INTRODUCTION Cyclopoid copepods represent a group with a dual position in trophic webs of plankton communities. Their early larval stages are herbivorous and feed on small algal cells. Later copepodite larvae and adults may feed on plankton algae but they gradually change their feeding mode to predation of plankton animals. The adults of large species even need a sufficient supply of animal food to be able to produce eggs (Smyly 1970) although Whitehouse & Lewis (1973) obtained repeated production of egg clutches from Cyclops abyssorum G. O. Sars, 1863, reared just on algal diet. Growing interest in the food relationships within the plankton community have led to a series of studies on both herbivorous and carnivorous feeding of various limnetic cyclopoid copepods (for review see Brandl 1998a). The published data show a very wide range of animal species preyed upon by cyclopoid copepods and significant impact of their predatory feeding on the other zooplankton populations. The aim of this work is to present data about the food composition of the cyclopoid species and about the impact of their predation on the other zooplankton in a carp pond. We believe that even relatively old data can contribute to the contemporary discussion on the extent of herbivorous and carnivorous feeding of cyclopoid copepods.

MATERIAL AND METHODS

During the period of intensive studies on pond ecosystems in carp ponds near Blatná, SW Bohemia, made by the team of the Department of Parasitology and Hydrobiology, Faculty of Science, Charles University, detailed data were obtained on zooplankton and its seasonal changes in several carp ponds. In 1980 and 1981 we performed

This contribution is dedicated to Doc. RNDr. Jaroslav Hrbáček, DrSc., upon the occasion of the 80th anniversary of his birthday (12th May 1921).

169 Tab. 1. Predation rates of the cyclopoid copepods on the rotifer, cladoceran and copepod prey in the pond Velký Pálenec, 1980–1981

Prey species No. of exp. series prey density, predation rate, prey×l–1, range prey×predator–1×day–1, median and (range) Asplanchna sp. 6 1–1224 0.33 (0.05–0.80) Brachionus angularis 2 6, 16 0.08 (0.02, 0.14) Brachionus rubens 2 164, 409 2.60 (2.57, 2.63) Conochilus unicornis 3 1–50 0.39 (0.10–0.50) Keratella cochlearis 10 1–1485 0.86 (0.05–4.79) Keratella quadrata 9 1–89 0.07 (0.02–0.64) Polyarthra dolichoptera 15 2–261 0.40 (0.02–15.4) Pompholyx sulcata 2 133, 390 0.08 (0.04, 0.13) Synchaeta sp. 2 104, 245 2.76 (2.45, 3.06) Daphnia galeata 6 3–283 0.35 (0.02–1.52) Diaphanosoma brachyurum 1 24 0.03 Bosmina longirostris 2 1, 34 0.24 (0.03–0.46) Copepoda, naupliar larvae 15 27–405 0.38 (0.06–2.32) Cyclopidae, copepodite larvae 12 9–198 0.12 (0.05–0.70) Eudiaptomus, copepodite larvae 3 1–40 0.02 (0.01–0.05) paralell measurements of predatory feeding of carnivorous cyclopoid copepods in the pond Velký Pálenec (for the description and detailed characteristics of this pond, see e.g., Hrbáček 1966, Fott et al. 1974 or Kořínek et al. 1987). This 31-ha eutrophic pond with an average depth of 1.44 m is used for carp cultivation, usually in a two- year cycle with complete draining at the end of each cycle. The experimental procedure used to measure the predation of cyclopoid copepods was essentially the same as described by Brandl & Fernando (1978). The natural pond zooplankton was collected from a known volume of water and concentrated. The size fraction containing predatory stages of cyclopoid copepods was separated from the prey zooplankton by screening through metal sieves of convenient mesh size. The “prey zooplankton” (both smaller and larger than the predators) was then thoroughly mixed and evenly distributed into experimental and control replicates (usually two of each). The size fraction containing the predators was added only to the experimental series of replicates. The replicates placed in 5-litre plastic bottles were re-diluted with filtered pond water to the original pond zooplankton concentration. The bottles were hung in a horizontal position in the pond for 24 hours. Then their content was concentrated using 0.04 mm sieve, preserved in 4% formalin and counted under the microscope. The difference between the experimental and control series after 24 hours was then attributed to predation by the cyclopoid copepods present in the experimental replicates. When egg-bearing females of either cyclopoid copepods or other plankton animals were present in the “predator” size fraction, a correction was applied in the experimental series for the number of newborn naupliar larvae or cladoceran neonates. The correction was calculated from the number of eggs of each species per replicate, counted from two other replicates preserved in the beginning of the experiments, and from the known temperature-related rate of embryonic development (e. g., Bottrell et al. 1976, Herzig 1983). The qualitative and quantitative data on species composition of zooplankton in the pond were derived from representative samples (Hrbáček 1966) taken across the pond using a 30-litre Schindler sampler and resulting usually in a sample from 450 l of water (data of the second author).

RESULTS The cyclopoid copepods and their share in the plankton community Three species of cyclopoid copepods represented predators in the pond community. The most constant component was Cyclops vicinus Uljanin, 1875. The adults were present year-round in densities usually between 1 and 10 per litre, rarely 3× more (June 1980). The later larval stages were more numerous especially in spring and fall months when the density of copepodite larvae reached

170 almost 100. l–1. The second important, and temporarily even more numerous species, was Acan- thocyclops robustus (G. O. Sars, 1863) with occurrence seasonally limited to the second half of the vegetation season. In 1980, the adults appeared in late June and reached high densities in Septem- ber (28×l–1). In 1981, the period was the same: first adult males appeared in June, maximum density of 28×l–1 was recorded in early September. The density of the later (IV+V) copepodite stages was above 80×l–1 in September with more than 100×l–1 of younger copepodite larvae. This species completely dissappeared from the community in late October. The third species occurring in much lower densities (usually less than 1×l–1 and rarely between 1 and 5 per litre) was Cyclops strenuus Fischer, 1851. The adults of this species were present from June to October in 1980 and from early spring till August in 1981. Other species of cyclopoid copepods were recorded only occassionally in very low densities as Mesocyclops leuckarti (Claus, 1857) or Eucyclops serrulatus (Fischer, 1851) . The most numerous representatives of cyclopoid copepods were always their naupliar larvae, reaching densities of hundreds per litre (the maximum value 405×l–1 in May, 1980). However, due to their herbivorous feeding mode they rather should be considered one of the possible prey species. The herbivorous species available as a prey to cyclopoid copepods The main component of the pond zooplankton community were cladocerans, represented mostly by Daphnia galeata Sars, 1864. This is a relatively large species, namely in carp ponds with low fish predation of large crustaceans, but its juveniles may become the prey of cyclopoid copepods. Except for early spring and late autumn, the density of this species was always between 30 and 300 per litre, with more juveniles than adults. The other species of the same genus, the larger Daphnia pulicaria Forbes, 1893, was rare in 1980 and more common in 1981 (up to 48×l–1 in May). Other cladocerans were less important and occurred in low densities (Ceriodaphnia Dana, 1853) or with seasonally limited period of higher densities (Bosmina longirostris (O. F. Müller, 1785): 16–30×l–1

Fig. l. Predatory impact of cyclopoid copepods on cladocerans, copepods and rotifers in the pond Velký Pálenec, 1980: density per litre and the part eaten daily by cyclopoid copepods.

171 Tab. 2. Predation by cyclopoid copepods on Daphnia galeata juveniles (females not yet reproducing) compared to the reproduction of the Daphnia population, data for the 1980 cases of significant predation on Daphnia

Date June 23 September 3 October 1 temperature, °C 18.4 17.3 13.6 Cyclopidae, predatory stages, density per litre 25.8 52.5 116.9 Daphnia galeata, juveniles, density per litre 205.4 122.2 87.3 newborn Daphnia galeata, % per day 5.9 11.7 14.2 D. galeata eaten by copepods, % per day 2.7 9.4 3.5 in October 1981, Diaphanosoma brachyurum (Liévin, 1848): 24×l–1 in August, 1980 and 8×l–1 in August, 1981). Another possible crustacean prey, the copepodite larvae of two herbivorous calanoid copepods Eudiaptomus gracilis (G. O. Sars, 1863) and E. vulgaris (Schmeil, 1898) were almost always present but they reached higher densities only in June (40×l–1 in 1980 and 13×l–1 in 1981). The most numerous available prey were rotifers. We recorded 12 common species with up to 9 of them present at the same time. However, the occurrence of individual species was highly seasonal and their maximum densities were usually limited to periods of few weeks. Then they reached densities of up to hundreds per litre. In some species, these densities persisted for longer periods – Keratella cochlearis (Gosse, 1851): 300–790×l–1 in August and September, 1980, and 110– 1485×l–1 in the same period of 1981. For the ranges of densities of some species, see Table 1. Prey selection and predation rates of cyclopoid copepods The list of species for which we recorded significant difference between the experimental and the control treatments contained all possible prey species which were at least sometimes present in higher densities. They included nine species of rotifers, three cladocerans, naupliar and the small copepodite larvae of copepods (see Table 1). The most important component of the prey of cyclopoid copepods were rotifers. The per capita predation rates by cyclopoid copepods of some species of rotifers reached several specimens per day during the periods of high rotifer densities (Polyarthra dolichoptera Idelson, 1925, Keratella cochlearis) but were low when a given rotifer species was rare. Consistently high values were recorded for species with limited periods of occurrence (Brachionus rubens Ehrenberg, 1838, Synchaeta sp.). The rates of feeding on cladocerans were lower, especially when evaluated in relation to the high possible gain of food in contrast to small rotifers. In most cases, the feeding rate on Daphnia galeata was insignificant or not measurable. We recorded only six cases of significant values. Those which we could compare with direct measurement of reproduction rate (1980) are given in Table 2. They account for about a half of the production of Daphnia neonates per day. The last, but not least, component of cyclopoid prey were younger copepodite and especially naupliar larvae. The significant values of predation rates on one or the other of the larval stages were recorded in all but one cases of our measurements. The impact of predation on the whole zooplankton community The summarized values of the daily eaten prey in terms of prey specimens compared to the overall densities for the categories of cladocerans, copepods and rotifers are given in Figures 1 and 2. Since the size and biomass are very different for individual prey species these figures give just a rough idea of the impact of predation. Neverheless it is obvious that the predation is oriented mostly towards the rotifer component of the zooplankton community especially during periods of the high rotifer density. The relatively high impact of copepod predation on their own category is the result of feeding on naupliar larvae rather than on the larger copepodite larvae. A high impact of the copepod predation on newborn Daphnia galeata was found as well, but only occasionally (Tab. 2).

172 DISCUSSION Cyclopoid copepods inhabiting the pond Velký Pálenec (i.e. mainly Cyclops vicinus and Acan- thocyclops robustus) in both years caused measurable differences in prey densities between the control and the experimental series of containers for at least part of the possible prey species present in the pond. Whenever some species of rotifers were present in high densities they became the preferred type of prey and per capita daily predation rates grew up to several specimens of species like Polyarthra dolichoptera and Keratella cochlearis. Also the species which occurred for just short periods, but in high numbers, were intensively preyed upon. The preference of cyclopoid copepods for rotifer prey agrees with the data of numerous authors (from more recent e.g. Diéguez & Gilbert 2002 or Plassman et al. 1997, for review of earlier data see Brandl 1998a). Plassman et al. (1997) found that Cyclops vicinus preferred Synchaeta spp. to species of Keratella Bory de St. Vincent, 1822, and Polyarthra Ehrenberg, 1834, in Lake Constance. This agrees with our data on high predation of Synchaeta Ehrenberg, 1832, in early spring when Cy- clops vicinus and C. strenuus were present in the pond whereas Acanthocyclops was not. Brandl (1998b) found per capita daily predation rates by Cyclops vicinus in two Czech reservoirs up to 4.2 for preying on Polyarthra dolichoptera and up to 3.4 for Keratella cochlearis. However, the rotifer population densities were also lower in reservoirs than in the pond Velký Pálenec. Moreo- ver, high copepod predation of rotifers of the other two most common genera, Polyarthra and Keratella, can be at least partially attributed to the third cyclopoid predator, Acanthocyclops robustus. This species is probably also responsible for predation of juvenile specimens of Daph- nia galeata since we found the significant values of Daphnia consumption right in the periods of high densities of adult and later larval stages of Acanthocyclops occurring at the same time as high density of Daphnia. The increase of the Acanthocyclops robustus predation of Daphnia sp. was also reported by Roche (1990). Similarly Caramujo & Boavida (2000) who studied the tail spine

Fig. 2. Predatory impact of cyclopoid copepods on cladocerans, copepods and rotifers in the pond Velký Pálenec, 1981: density per litre and the part eaten daily by cyclopoid copepods.

173 elongation in Daphnia as a defence mechanism against Acanthocyclops predation found significantly high values of predation rates by Acanthocyclops robustus on the youngest instars of Daphnia hyalina x galeata. An even more important component of cyclopoid food than Daphnia are the naupliar and younger copepodite larvae of both cyclopoid and calanoid copepods. Cannibalistic predation is a common feeding mode in cyclopoid copepods (see e.g. Gabriel 1985). Brandl & Fernando (1978, 1981) reported the predation of naupliar larvae by Cyclops vicinus in pond and reservoir populations. The extent of the predatory impact of cyclopoid copepods on the other zooplankton in the pond Velký Pálenec varied from very low or zero values for some of the three groups of plankton animals (usually cladocerans or rarely copepods) to a relatively high percentage, between 10 and 20 percent for the rotifer populations. Occasional high values for copepods occurred in the late spring when the cyclopoid copepods were slowly receding from the plankton community and entering their diapause phase on the bottom. During the past decade, algae have been more closely examined as an important food source for adult cyclopoid copepods and their later copepodite stages, and the share of the herbivorous and the carnivorous feeding mode have been discussed (e.g. Adrian 1991, Hansen & Jeppesen 1992, Santer 1993, Santer & Bosch 1994, Hansen 1996). There is no doubt that especially Cyclops vicinus feeds opportunistically on large algal cells, coenobia or colonies since the algal material can often be seen in the guts of living animals. However, the predation by cyclopoid copepods on the other zooplankton species is an equally important mode of feeding and its impact on the other species may often be essential for the further population development of the prey species.

A c k n o w l e d g e m e n t s We are especially happy to contribute to this special issue dedicated to Jaroslav Hrbáček on the occassion of his 80th birthday. The first author thanks J. Hrbáček for many hours of invaluable discussions on various productivity problems of water ecosystems and for the orientation to prospective topics in this research. The evaluation of data was supported by the grant No. K 6005114 GA AV ČR. C. M. Steer greatly improved the English of this paper.

REFERENCES

ADRIAN R. 1991: Filtering and feeding rates of cyclopoid copepods feeding on phytoplankton. Hydrobiologia 210: 217–223. BOTTRELL H. H., DUNCAN A., GLIWICZ Z. M., GRYGIEREK E., HERZIG A., HILLBRICHT-ILLKOWSKA A., KURASAWA H., LARSSON P. & W EGLENSKA T. 1976: A review of some problems in zooplankton production studies. Norw. J. Zool. 24: 419–456. BRANDL Z. 1998a: Feeding strategies of planktonic cyclopoids in lacustrine ecosystems. J. Marine Systems 15: 87–95. BRANDL Z. 1998b: Life strategy and feeding relations of Cyclops vicinus in two reservoirs. Internat. Rev. Hydrobiol. 83: 381–388. BRANDL Z. & FERNANDO C. H. 1978: Prey selection by the cyclopoid copepods Mesocyclops edax and Cyclops vicinus. Verh. Internat. Verein. Limnol. 20: 2505–2510. BRANDL Z. & FERNANDO C. H. 1981: The impact of predation by cyclopoid copepods on zooplankton. Verh. Internat.Verein. Limnol. 21: 1573–1577. CARAMUJO M.-J. & BOAVIDA M.-J. 2000: Induction and costs of tail spine elongation in Daphnia hyalina × galeata: reduction of susceptibility to copepod predation. Freshwater Biol. 45: 413–423. DIÉGUEZ M. C. & GILBERT J. J. 2002: Suppression of the rotifer Polyarthra remata by the omnivorous copepod Tropocyclops extensus: predation or competition. J. Plankton Res. 24: 359–369. FOTT J., KOŘÍNEK V., P RAŽÁKOVÁ M., VONDRUŠ B. & FOREJT K. 1974: Seasonal development of phytoplankton in fish ponds. Internat. Revue Ges. Hydrobiol. 59: 629–641.

174 GABRIEL W. 1985: Overcoming food limitation by cannibalism: A model study on cyclopoids. Arch. Hydrobiol. Beih. Ergebn. Limnol. 21: 373–381. HANSEN A.-M. 1996: Variable life history of a cyclopoid copepod: the role of food availability. Hydrobiologia 320: 223–227. HANSEN A.-M. & JEPPESEN E. 1992: Life cycle of Cyclops vicinus in relation to food availability, predation, diapause and temperature. J. Plankton Res. 14: 591–605. HERZIG A. 1983: The ecological significance of the relationship between temperature and duration of embryonic development in planktonic freshwater copepods. Hydrobiologia 100: 65–91. HRBÁČEK J. 1966: A morphometrical study of some backwaters and fish ponds in relation to the representative plankton samples. Pp.: 221–257. In: HRBÁČEK J. (ed.) Hydrobiological Studies 1. Praha: Academia Publ. House, 408 pp. KOŘÍNEK V. , F OTT J., FUKSA J., LELLÁK J. & PRAŽÁKOVÁ M. 1987: Carp ponds of Central Europe. Pp.: 29–62. In: MICHAEL R. G. (ed.) Managed aquatic ecosystems. Amsterdam: Elsevier, 300 pp. PLASSMANN T., MAIER G. & STICH H. B. 1997: Predation impact of Cyclops vicinus on rotifer community in Lake Constance in spring. J. Plankton Res. 19: 1069–1079. ROCHE K. 1990: Prey features affecting ingestion rates by Acanthocyclops robustus (Copepoda: Cyclopoida) on zooplankton. Oecologia 83: 76–82. SANTER B. 1993: Potential importance of algae in the diet od adult Cyclops vicinus. Freshwater Biol. 30: 269– 278. SANTER B. & VAN DEN BOSCH F. 1994: Herbivorous nutrition of Cyclops vicinus: the effect of a pure algal diet on feeding, development, reproduction and life cycle. J. Plankton Res. 16: 171–195. SMYLY W. J. P. 1970: Observations on rate of development, longevity and fecundity of Acanthocyclops viridis (Jurine) (Copepoda, Cyclopoida) in relation to type of prey. Crustaceana 18: 21–36. WHITEHOUSE J. W. & LEWIS B. G. 1973: The effect of diet and density on development, size and egg production in Cyclops abyssorum Sars, 1863 (Copepoda, Cyclopoida). Crustaceana 25: 225–236.

175 Acta Soc. Zool. Bohem. 66: 176, 2002 ISSN 1211-376X

BOOK REVIEW

MEHLHORN H. (ed.): Encyclopedic Reference of Parasitology. Second edition. Springer-Verlag: Berlin- Heidelberg-New York, etc., 2001. Format 190×268 mm. First volume: Biology, Structure, Function. XXI+670 pages. Hardcover. Price sFr 326.00. ISBN 3-540-66819-5. Second volume: Diseases, Treatment, Therapy. Hardcover. Price sFr 257.00. XXI+678 pages. ISBN 3-540-66829-2 The editor is professor at the Institute of Zoomorphology, Cell Biology and Parasitology of the Heinrich Heine University in Düsseldorf (Germany). The project of this publication involved 38 acknowledged authorities from Europe, USA and Brasil. As declared in the preface by the editor, this second edition intends to give a comprehensive overview of the facts and trends in veterinarian and human parasitology. It is to point up that this is an encyclopaedia, not a specialized textbook. The lay-out of the book presents an encyclopaedic arrangement of 2157 entries (key-words) in alphabetical order along the subject index being included in the flow of the text. For a book review, entries may be assembled into several thematic blocks. Particular entries embrace the extent from a simple reference to another page or a space-limited paragraph – up to an essay length of >10 textual pages. First volume comprises 1592 entries concerning biological/zoological aspects of parasitology. Entries that describe systematic assemblages of parasites consist of sections illuminating classification, distribution, morphology, genetics, reproduction, life cycles, feeding behaviour and transmission. Other thematic block directs attention on morphology and structural parts of parasitic organisms placing emphasis upon the fine structure. Unicel- lular protozoans are represented by entries describing external and internal organellae. Entries related to metazoan parasites, helminths and arthropods, encompass terms relevant to external and internal morphological structures and organ systems. Various physiological and metabolic functions and general outlines of evolution, ecology and other sciences related to parasitism are introduced by terms such as behaviour, coevolution, ecosystems, energy metabolism, encystation, environmental conditions, favorisation, host-parasite interface, local adaptation, nutrition of parasites, etc. Entries dedicated to biochemistry, molecular biology and genetics are concerned with terms such as aminoacids, deoxynucleotides, hybridization, extended phenotype, genome projects, proteases, glycosylphosphatidylinositols, nucleic acids, lipids, RNA editing, etc. Entries on other fields of interest and importance ensure coverage of arboviruses, host finding, immune diagnostic methods, phylogenetic relationships, serology, transmitted pathogens, and vector biology. Second volume embraces 565 entries covering topics related to pathogenical effects of parasitism in humans and animals, clinical aspects, diagnostic procedures, therapeutical regimens and schedules. Thematic block based on parasitic diseases is focused on general information, pathology, immune responses, evasion mechanisms, main clinical symptoms, chemotherapy, diagnosis, prophylaxis and vaccination, and control measurements. A special credit deserves the entry that gives insights into miscellaneous aspects of immunity. Moreover, particular sections surveying immune responses are situated in each entry examining a particular parasitic disease. These sections delineate in detail innate defense mechanisms, B cells and antibodies, T cells and cytokines, control of parasites by activated macrophages, immunopa- thology, autoimmunity, evasion mechanisms and vaccination. In other thematic block explored are general pathological terms such as respiratory, genital and nervous system diseases in animals, eye parasites, pathology, parasitaemia, parasite load, disease control, etc. Entries devoted to chemotherapy are introduced partly by terms related to parasitic agents, partly by terms characterizing their biological effect. Entries discussing other fields of interest are concerned with epidemiology, host reactions, opportunistic agents, serology, vector transmitted diseases and zoonoses. Both volumes are extensively illustrated by 497 (371+126) figures composed of schematic line drawings and photographs. In volume 1 featured are individual parasitic organisms – protozoans, helminths and arthropods in adult forms and developmental stages, enternal and internal structural parts, organs and tissues, structures of biomolecules, diverse biosynthetic and metabolic pathways, schematic representations of cell division, modes of reproduction and miscellaneous biological phenomena, genealogy of different chromosomes, phylogenetic trees and evolutionary schemes. Numerous original schematic life cycle drawings are of particular didactic value. Stereoscans depict most instructive aspects of parasitic arthropods. In volume 2 featured are pathological abnormalities and lesions, clinical conditions, fundoscopic findings, distribution maps, transmission cycles, structural formulae and models of action of drugs. 183 (76+107) detailed tabular summaries give excelent overwiews of data presented in the textual part. Compiled by a broad spectrum of internationally respected experts, this remarkable opus provides an authori- tative and most exhaustive encyclopaedia embracing all aspects of parasitology. Without doupt, this publication will become an indispensable necessity for libraries of professionals, universities and research institutes. Jindřich Jíra

176 Acta Soc. Zool. Bohem. 66: 177–188, 2002 ISSN 1211-376X

Taxonomy and conservation problems of the native salmonids (Pisces: Salmonidae) in the Danube river system: a review

Juraj HOLČÍK

Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9, SK–842 06 Bratislava, Slovakia; e-mail: [email protected]

Received May 15, 2002; accepted Septeber 3, 2002 Published November 4, 2002

Abstract. Five species of salmonids (Salmonidae sensu Reshetnikov, 1980) are recognized in the Danube River basin. The anadromous Salmo labrax Pallas, 1811, known from the lower course of the Danube proper is now very rare. Its lake derivative Salmo labrax (morph lacustris) still lives in some Austrian lakes. Its present status was described as disastrous, as it disappeared in some lakes and in other ones it was replaced by intentionally introduced lake trout of different origin. Another species of lake trout, the deepwater Salmo schiefermuelleri Bloch, 1784, endemic to some Austrian lakes seems to be completely extinct. Its proper taxonomic status is not clear yet. It is suggested that this taxon represented those specimens of the adult Salmo labrax lake form, which left out spawning for one or two years. The upper and middle Danube and its mountain and foothill tributaries are inhabited by the brook trout Salmo labrax (morph fario). Genus Salvelinus is represented by Salvelinus umbla (Linnaeus, 1758), and the deepwater species Salvelinus profundus Schillinger, 1901. From three forms of the former, the fast growing and predatory Wildfangsaibling and the zooplankton feeder Normalsaibling became probably extinct and only the deepwater Tiefseesaibling still survives in one lake. Also Salvelinus profundus, known from two Austrian lakes, is now probably extinct. Conservation status of the Danubian huchen Hucho hucho (Linnaeus, 1758) may be evaluated as critically endangered. Its range reduction recorded since 1945 seems to be halted in some countries, but in other it is decreasing and its populations are maintained mostly by extensive stocking. Taxonomy, conservation, Pisces, Salmonidae, Salmo labrax, Salmo schiefermuelleri, Salvelinus salvelinus, Salvelinus profundus, Hucho hucho, Danube river basin, Palaearctic region

INTRODUCTION The purpose of this paper is to initiate and/or promote research on the status of native salmonids inhabiting the Danube River basin, including their ecology and conservation and in most of them even their taxonomy and nomenclature. Danube basin is noted for both the highest total number and the highest ratio of endemic fish species in Europe (Berg 1932, Lindberg 1972). The Danube basin is also known as the Quaternary refuge of its freshwater fauna which, after the retreat of the ice sheat, expanded into other European river basins (Lindberg 1972). It is therefore astonishing, that relatively little is known about most Danubian native salmonids. This criticism deals both with their taxonomy and ecology, including their population density and in some respect even the fish catch statistics. It seems that most European ichthyologists were, and still are, interested in fishes from remote, exotic countries and not in those inhabiting rivers within reach of their hands. This is reason why the following data, although they were excerpted from all available information, give only an indistinct and in some respect confused picture on the present status of given species. In addition it seems, that most now belong to the endangered, and some species even among the extinct freshwater fishes of our Old continent.

To Dr. Jaroslav Hrbáček, Scholar, Teacher and Personage at the occassion of his 80th birthday.

177 Genus Salmo Linnaeus, 1758 Until now most authors suppose that European rivers are inhabited, besides forms of unknown systematic status, by three species of the genus Salmo, i.e. the Atlantic salmon Salmo salar Linnaeus, 1758 and the brown trout Salmo trutta Linnaeus, 1758, and by the marble trout Salmo marmoratus Cuvier, 1817. The brown trout forms three ecological forms, the sea trout –S.trutta (morph trutta), the brook trout – S. trutta (morph fario), and the lake trout – Salmo trutta (morph lacustris). This nomenclature implies close relationships of the migratory, stream resident and the lake resident forms respectively. However, it has been documented, that all three ecological forms inhabiting one river basin represent one gene pool and/or they are much more closely related each other, than to any of those from another river basin (Ferguson et al. 1995 and references therein). Moreover, recent data coming from population genetic analyses of various trout populations using both nuclear-gene (biochemical), nested clade and mtDNA markers throughout all over the Europe (e.g. Bernatchez et al. 1992, Riffel et al. 1995, Apostolidis et al. 1996 a, b, Bernatchez & Osinov 1995, Giuffra et al. 1995, Osinov & Bernatchez 1996, Bernatchez 2001) suggest that actual biological diversity of the brown trout might be far greater than it is recognised by the current taxonomy with its nomenclatorial limits (Kottelat 1997). This situation resembles that found recently in the another salmonid genus Oncorhynchus Suckley, 1861(Behnke 1992). In other words, recent data coming from using the karyotype pattern (Phillips & Ráb 1997) and the mtDNA and biochemical analysis of various stocks (Kottelat 1996, and literature herein) indicate the more complex species composition of European trouts. This postulate is now verified by the thorough analysis of the allozymes and mtDNA of the “brown trout” stocks from many localities covering various European and also Central Asian river basins, made by Osinov & Bernatch- ez (1996). Within five phylogenetic groups distinguished earlier (Bernatchez et al.1992, Giuffra et al.1994, Bernatchez & Osinov 1995, Bernatchez 1995, 2001) there are two large ones: the “Atlantic” group and the “Danubian” group, the last one involving “brown trout” stocks inhabiting streams and lakes belonging to the basins of the Black, Caspian and Aral seas. The migratory trouts of the Black Sea and the lower Danube have been described as a distinct species Salmo labrax Pallas, 1814, later on considered to be subspecies of Salmo trutta by Berg (1916). Afterwards Balon (1968, 1969) refused even the subspecific status of the Black Sea trout and the migratory trout from its watershed he considered to be a morph – Salmo trutta m. labrax – only. However, observations by Dorofeeva (1967, 1977, 1985), Osinov (1984, 1989), Bernatchez & Osinov (1995), Largiader & Scholl (1995), Togan et al.(1995) and Osinov & Bernatchez (1996) revealed some osteological, karyological, biochemical and molecular differences among particular subspecies of Salmo trutta, suggesting to attribute them specific status. This is particularly true for the Black Sea trout populations and Kottelat (1997) tentatively recognizes it as a distinct species, in spite that the recent list of the salmonids inhabiting the territory of Russia, only Salmo salar and Salmo trutta are still recognised, the latter with four subspecies – S. t. caspius Kessler, 1870, S. t. ciscaucasicus Dorofeeva, 1967, S. t. labrax Pallas, 1814, and S. t. ezenami Berg, 1948 (Dorofeeva & Savvaitova 1998) In this paper I follow the opinion of Kottelat (l. c.) and consider the Black Sea trout to be a valid species.

Salmo labrax Pallas, 1814 The main anatomical characters distinguishing this species from its closest relative Atlantic trout Salmo trutta Linnaeus, 1758, occurring in the watershed of the Atlantic Ocean is the higher number of gill rakers, the high caudal peduncle depth (Berg 1948, Pavlov et al. 1994) and the structure and dentition of some skull bones (Dorofeeva 1967). Also, as revealed just recently, there is a set of distinct genetic markers suggesting that it represents one gene pool (Ráb pers. comm.).

178 The Black Sea trout is a migratory species, living as adult in the littoral of the Black Sea and ascending rivers for spawning. The following details on its ecology and life history are taken from the papers by Berg (1948), Bănărescu (1964), Svetovidov (1964), Elanidze et al. (1970), Marinov (1978), Pavlov (1980), Elanidze (1983), and Pavlov et al. (1994). Spawning migration begins in February, it peaks in April and May and terminates in July. The spawning proper is in October, peaks in November and lasted till the end of January. Juveniles stay 2–4 years in the brooks where they hatched and only then move downstream to their feeding grounds in the sea. Characteristic feature of this species is strong predominance of females: in some rivers the migratory and resident trouts form one stock, where migrants are represented by females which mate with males belonging to the resident brook form (m. fario). In this case part of hatched juveniles does not transform to smolts and stay in a stream. Smoltification is determined by sex, as only females leave the river while males remain there. Sexual maturation sets in at the age of 3–5 years and 350–900 mm of the total length (Tl). The diet of juveniles is composed of invertebrates only, but smolts start to eat also fish. The major food of adults in the sea is fish, mostly anchovy [Thryssa (syn. Engraulis) encrasicholus (Linnaeus, 1758)]. The main distribution of this trout are eastern shores of the Black Sea and the Azov Sea but it is known also from the shores of Crimea, Ukraine, Romania, Bulgaria and Turkey. It ascended the rivers of Crimea and Caucasus and also the rivers Dnieper (formerly up to Kremenchug, some 500 km from the river mouth), Don (up to Pavlovsk) and Kuban’ with its tributary Laba (some 300 km upstream). In the Danube River it was known from Silistra and Orecho- vo, 350 and 700 km upstream from its delta, respectively, and in the delta lakes Razelm and Yalpukh. In comparison with eastern stock the western one was always less abundant and only single specimens weighing mostly 3–4 kg were taken. Maximum recorded size of this species was 1100 mm and 24 kg. At present the population of this species generally dropped dramatically and only few specimens are sometimes taken. In the main fishing grounds along the Georgian shores, where formerly 9 tons were taken annually, the fishery for this species had to be completely stopped. However, I must say that the exact status of the trout in the lower Danube is not known, in spite that the local fishermen known this trout perfectly. Only few and generally small-sized specimens are occasionally caught there (Bănărescu 1964, Pavlov 1980) and Balon (1968, 1969) considered them to be resident, non-migratory trouts washed downstream from the Danube river basin. Ac- cording to Suciu (pers.comm.) the Romanian trout catch in the Danube delta is about 100 individuals annually and their length and weight varies from 400 to 520 mm Tl and 100–1800 g, respectively. Trouts found in the middle Danube have a similar colouration as the sea trouts and lake trouts, i.e. only black spots are scattered on their dorsum and flanks (Holčík 1969). The status of the sea trout from the Black Sea was evaluated by Lelek (1987) as endangered and by Pavlov et al. (1994) as vulnerable. However, the situation in the Danube basin is more critical, so the actual conservation status of this species at the western range of its area may be evaluated as critically endangered. The reasons of its decline are not properly known but it is certainly the combination of overfishing and the deteriorated environmental conditions, including pollution, construction works, and damming of streams where this species spawns. A list of conservation measures proposed by Lelek (1987) includes environmental protection, fishing restrictions, establishing of hatcheries and also intensive research focused on the population ecology of this species. Russian authors (Pav- lov et al.1994) recommend also the the exclusive use of the local brown trout stock in hatcheries. Most Alpine and pre-Alpine lakes in Austria are inhabited by the lake form – the lake trout Salmo labrax (m. lacustris). This form resembles the sea trout in form and also colouration, however it is much larger as it grows up to 31 kg. Its ecology is similar to that of both the sea trout and brown trout, but details are not well known. Sexual maturity is reached and first spawning performed only when fish attains 500 mm in the Tl, i.e. as 4 (3+) and 5 (4+) years old males and

179 females, respectively. In late autumn the lake trout migrates into lake tributaries, sometimes even into the outlets to spawn and afterwards it returns to the lake. In rare occasions the spawning was also observed in the lake itself, but usually close to the mouth of tributaries. In some localities the spawning with the resident brook trout was observed, but hybrids are said to display lower growth rate and they attain much smaller size than the lake trout (Hochleithner 1989). Two forms of the lake trout were recognized in particular lakes. They differs in the size, colour and the diet as well. Small, light-coloured and sexually immature fish called Schwebforelle, Silberforelle, Silberlachs or Ju- gendform inhabits upper layers of the water column, dwells close to shores and feeds on the airborn insects or small fishes. Large, dark and adult specimens called Grundforelle inhabit pela- gial and are confined to depths up to 40 m below surface. They are typical predators preying on fish. Present conservation status of the lake trout in Austrian lakes was described as disastrous by Hochleithner (1989). This author made an attempt to assess its actual situation and tried to check populations inhabiting particular Austrian lakes. However, his data are based on reports of various persons, they lack quantitative figures dealing with population abundance and fish catch statistics. Due to this the following review is only a very rough and somewhat subjective simplification. From 14 lakes of the Danube basin the lake trout catches and recorded individual maximum or mean weights decreased in six (43%), seems to remain the same in four (28%) and improved in one (7%) lake. In three lakes, however, (Fuschlsee, Traunsee and Hallstättersee; 21%), the lake trout is now extinct. Individual weight of the lake trout catches from these lakes, recorded mostly till the first half of this century, attained up to 31 kg. As noted by Einsele (1959) 20 kg specimens were not rare. At present, however, the catches of individuals over 10 kg are very rare and the mean weight recorded during last years varied mostly from 6–8 kg. Both Hochleithner (l. c.) and Jagdsch (pers. comm.) claimed that reason of the decline of the lake trout is a combination of overfishing and environmental changes, including alteration or damage of the spawning grounds by construction works, and weirs and dams which have cut access to spawning grounds, and pollution and eutrofication which kill the fertilised eggs and hatching alevins, as well as the food resources for juveniles. Both Hochleithner and Jagdsch also stressed the wrong management which contribut- ed to the decreasing trend of the lake trout stock in the Alpine and pre-Alpine lakes. With the aim to improve the population density of this species, foreign, (mainly Danish strains) of the sea trout (i.e. Salmo trutta [m. trutta]) reported to be the lake trout, were imported to Austria and stocked into the lakes. The imported trouts are accused to hybridise with the true, native, lake trouts. Their hybrids are noted, for both their lower growth rate and individual weight, but no data were introduced to support this assertion. This, however, does not indicate the introgression of the imported trout of the Atlantic origin. Largiader & Scholl (1995) found that indigeneous genetic variation in the brown trout populations is still predominant in the Danube basin in Switzerland despite stocking. The low impact of foreign brown trout strains was also found also elsewhere as documented by Arias et al. (1995) in Spain, Beaudou et al. (1994, 1995), Poteaux et al. (1998) in France and by Ráb (pers. comm.) in former Czechoslovakia. The same seems to be valid for the genus Salvelinus (Kummer & Jungwirth 1999). According to Jagdsch (pers. comm.) the present managing practice in Austria improved. Stock- ing activity is now based on the native lake trout progeny, and the Grundlsee and the Attersee lakes provide the original brood stocks for hatcheries. According to the Red List of endangered fishes in Austria the situation seemed to have improved during past decade. While in 1983 the lake trout was listed among endangered fish species (Hacker 1983) in 1989 it had moved to the vulnerable category (Herzig-Straschil 1994). In Switzerland, the lake trout now occurs in only one lake of 6 lakes of the Danube basin populated by fish and the species is evaluated as critically endangered (Pedroli et al.1991).

180 There is one more species of the genus Salmo described from the Alpian lakes. It is Salmo schiefermuelleri Bloch, 1784, known under vernacular name Mayforelle, sometimes also Silber- forelle. This is a mysterious fish, whose vernacular name is derived from the observation that it might be seen close to the lake surface only in spring, while during most of the year it dwells in greater depths. This form was known to inhabit the lakes Attersee, Traunsee and Fuschlersee (Heckel & Kner 1854). It was reported to grow to the same large size as the deep-water lake trout or Grundforelle, i.e. 20–30 kg. According to Heckel (1851) and Heckel & Kner (1858), the difference between the deep-water Grundforelle and the Mayforelle is in the head shape, coloration, more deciduous scales, white eggs which would be of the same size as the millet seeds (while in the Grundforelle they are of the size of the pea seeds) and hardships to keep it alive. Systematic status of this trout is not solved yet. Haempel (1930) thought that the Mayforelle is only a sterile form of the lake trout. Berg (1932, 1948) considered it as a synonym of the Danubian basin lake trout – Salmo trutta labrax according to his nomenclature – while Balon (1968) supposed it to be the infraspecies i.e. ecological form of the species Salmo trutta. According to Kottelat (1997) Salmo schieffermuelleri is a valid species. With respect to data by Heckel & Kner (1858) and Haempel (1930) dealing with small eggs and/or its reproductive sterility, I suppose that the Mayforelle are those specimens of the adult lake trout (Grundforelle) which left out spawning for one or two years. Such a situation is known in various species of fishes including coregonids and salmonids occurring in northern regions or in deep lakes (Kennedy 1953, Grainger 1953, Gullestad 1973, Holčík et al. 1988). The exact taxonomy of this trout remains to be solved. However, the original stock seems to be extinct (Balon 1968, Kottelat 1997).

Genus Salvelinus Richardson, 1836 The systematics and nomenclature of the charrs, genus Salvelinus are even more obscure than those of the trouts. As pointed out by Kottelat (1997), here the main problem is the existence of a number of various stocks, which are variously called, and even were described as species, subspecies, forms, ecomorphs, etc. Moreover, possible transition of charrs originating from sympatric speciation from one form to other in the ontogeny, and, in some cases reproductively isolated and morphologically, ecologically and genetically different forms (Alekseyev et al. 1999, Dynes et al. 1999) complicate the situation and taxonomic status of particular stocks. Berg (1932) recognized 25 valid species in Europe, afterwards he (Berg 1948) lumped them into two. One is Salvelinus alpinus (Linnaeus, 1758) occurring in the lakes of Finland, Sveden (lake Vättern), southern Norway, in Alpine lakes (lakes in the watersheds of the rivers Danube, Rhine, Rhône), lakes on the British Isles, Orkney and Shetland islands, in Iceland, Kola peninsula, Karelia and in the lakes Onega and Ladoga. The second charr species is Salvelinus lepechini (Gmelin, 1780) inhabiting some lakes in Finland, Sweden (lakes Mälaren and Vennern) and southern Norway. Ladiges & Vogt (1979) recognised only one species, Salvelinus alpinus (Linnaeus, 1758) with 24 subspecies. According to Kottelat (1997) who extensively reviewed all available data, there are 23 valid species in Europe: 7 in England, Wales and Scotland, 6 in Ireland, 3 in Iceland, 2 in the Alps and 4 different species in Scandinavia, in the Onega and Ladoga lakes, in the Shetland, Orkney and Faroe islands, respectively. In the Danube river watershed Kottelat (l.c.) distinguishes Salvelinus umbla and Salveli- nus profundus. The name Salvelinus umbla has nomenclatorial priority over the name S. salvelinus and S. alpinus salvelinus (Linnaeus, (1758) (Kottelat 1997), which was traditionally used just for charrs of lakes in Alps.

181 Salvelinus umbla (Linnaeus, 1758) The Alpine charr, was described from various Alpine and pre-Alpine lakes, among them also Mondsee, Traunsee, Königssee and lakes of the Salzkammergut region in Austria, all in the watershed of the Danube river. Three different forms were known to inhabit them: (1) the dwarf deep- water Tiefseesaibling (also known under the names Schwarzreuter and/or Hungersaibling) attaining 170–250 mm in Tl, inhabiting the deep parts of the lakes and feeding on zooplankton, (2) the Normalsaibling feeding on zooplankton and zoobenthos, and (3) the Wildfangsaibling which is the largest (attaining 650–750 mm in Tl and 3–5 kg in weight), predatory and occurs in two forms, the yellow and white one (Buresch 1925, Haempel 1924, 1930, Berg 1932, Ladiges & Vogt 1965). Heckel & Kner (1858) and Schindler (1940) supposed that the Normalsaibling and the Wildfang- saibling are only different age classes of the same species. Kottelat (1997) suggests that in these lakes were at least two species, the deep-water and the “normal” one, which were morphologically distinct, and with different parental ancestry and descent. There is no doubt that the deep-water Tiefseesaibling belongs to different species Salvelinus profundus as it will be shown below. Morphology and ecology of these forms in Alpine lakes of the Danube basin are not properly known and the more or less complete information for the “normal” form are those by Dörfel (1974) from the Lake Constance (Bodensee; the Rhine River Basin). He found that it dwells in depth not exceeding 60 m. The diet is composed of the chironomid pupae (75%), copepods (15%) and chironomid larvae (10%). Spawning periods in first half of December and sexual maturation sets at age 3 years. Sexual dimorphism is well developed and in addition to more bright colouration, males display also a kype of their lower jaw. Maximum size was 278–441 mm Tl at 5 years. Fecundity of this form varied from 900 to 2000 eggs. Concerning the present status of this charr species in Austria, the following information are mostly from Wanzenböck (pers.comm.) and Jagdsch (pers.comm.). Indigenous populations in Austria still exist in 16 lakes. In two additional lakes (Irrsee in Upper Austria, Zellersee in the Salzburg county) the Alpine charr became extinct in the 1960ies following eutrophication and in the medieval time because of mining, respectively. A restocking program of the Zellersee was established in 1985. In the lakes Grundlsee, Altausser-See and also in the Attersee, this charr is still the commercially most important species together with whitefish (Coregonus spp.). In other lakes as in Mondsee and Wolfgangsee, the stocks of charr are much smaller and a following general pattern is observed: increasing eutrophication is accom- panied with decreasing density of the charr, the dominant position of which is replaced by the whitefish. This phenomenon when salmonids are replaced by coregonids is well known also from other oligotrophic lakes in Eurasia and North America (see e.g., Colby et al.1977, Reshetnikov 1980, Holčík et al.1989). Wanzenböck suggests that competition between char and whitefish played also an important role, since alternating trends in the stock developments are obvious: overfishing of charrs led to increase in whitefish stock and vice versa. Both authors point out that the most serious problem might be the mixing of stocks from different lakes leading to the genetic erosion of different forms adapted to the specific conditions of particular lakes. Stocking material sometimes does not come from nearby lakes but also outside Austria, even from Scandinavia and Canada (Jagdsch 1987). With re-oligotrophication of many other lakes (e.g., Mondsee) signs of improve- ment of the charr stock have become obvious in recent years. In many small lakes in the high Alps, the charr have been introduced since the Middle Ages in habitats in which the fish can just survive, forming dwarf forms. But because these are not primary habitats for the species, its disappearance from some of these lakes cannot be regarded as the sign of danger. According to Wanzenböck the situation of native charrs in Austria is generally not bad, but Jagdsch (pers. comm.) estimates the char catch much lower than l kg.ha–1. According to Maitland (1995) who sampled information by questionnaire in December 1993, 15 Austrian lakes still have indigenous

182 charr population, 13 lakes have indigenous plus introduced stocks from elsewhere and there are 150 lakes with introduced charr. This species is still economically important and the Austrian charr catch in 1993 was 30 000 specimens taken by anglers and 35 metric tons, fished commercially. Nevertheless, this species is regarded as endangered (see also Hacker 1983 and Herzig-Straschil 1994). Salvelinus profundus Schillinger, 1901 It is another mysterious salmonid species reported from the Alpine lakes. It was formally named by Schillinger (1901) as Salmo salvelinus var. profundus from the lakes Constance and Ammersee. The proper and taxonomically correct description, however, has never been published. In spite of this already Berg (1932), then Behnke (1972, 1980), Cavender (1980) and at present Kottelat (1997) consider it to be a valid species. Its characteristic features are blunt and steeply downward bent snout, almost inferior mouth, large eyes and large teeth. This species has a lower number of gill rakers (l9–27, M=22.3) than the “Normalsaibling” (25–31, 0=27.7) and also its structure is different (Dörfel 1974, Behnke 1980, Cavender 1980). Its colouration is similar to that of the whitefish, without any spots, and it does not change in the period of spawning. There is no sexual dimorphism. Its ecology was studied by Brenner (1980) in Atterssee. He found that it dwells in depths from 40 to 130 m, both sexes became sexually mature in the third year of life, the main spawning period is between July and the beginning of November. However, sexually mature specimens of both sexes were caught, and monthly fertilisation tests were positive throughout the year, demon- strating that this charr reproduces all year round. The main spawning grounds in Attersee were at depths between 40 and 60 m and consisted of gravel with grains of 1.5–2.5 cm in diameter. The egg number of females 145–205 mm in Tl varied from 220–260 and decreased with increasing female size. The food of this charr consisted mainly of crustacean zooplankton, but fish eggs and remain- ders of fish were also found in its intestines. The growth of females and males appeared to be the same and the largest specimens were 6 years old and 160–190 mm Tl. It is of interest that 55 years ago the growth rate of this charr in the same lake was better, as 4 years old specimens reached 250 mm in Tl (Buresch 1925). It is worthwile to mention also that Brenner (1980) found in Attersee only this deep-water form but other two forms had disappeared, reportedly due to overfishing. The same situation probably also happened in other Alpine lakes. From other sources we know, that this deep-water charr may be found at depths around 100 m together with a whitefish (Coregonus spp.). When taken on the surface it becomes flatulent. Its maximum size is 150–175 mm. The female is able to spawn at the size of 100 mm Tl. Spawning period is in December and January. Data gathered by Dörfel (1974) from the Bodensee (Rhine basin) are similar and convincingly show morphological and ecological differences between the “normal” and a deep-water form allowing to admit the species status also to the latter. As Kottelat (l.c.) noted, it should urgently be investigated if the deepwater populations (of which several seem extinct) from various Alpine lakes are conspecific or not. It is of interest that in Transbaikalian lake Davatchan the deepwater dwarf charr occurs, resembling S.profundus in many characters. As pointed out by (Alekseyev et al. 1999) this form represents an interesting example of parallel evolution in deepwater mountain lakes.

Genus Hucho (Linnaeus, 1758) Hucho hucho (Linnaeus, 1758) The present distribution of this species is only a part of the earlier one. Historical records show that the huchen was quite common in almost all rivers of the Danubian watershed and this species inhabited almost 12 000 km of rivers in Europe. However, after 1945 the situation changed and by

183 the end of 1980s it disappeared from 39%, became rare in 28% and is now common in only about 33% of its former distribution. The present situation in those countries we have information from, is as follows. In Switzerland huchen occurred in the Inn River in the Engadin valley, but now is extinct as during past 50 years was not recorded there (Pedroli et al.1991). In Germany the huchen still occurs in the Danube and Iller in the vicinity of Ulm, but is rare and maintained by continuous stocking (Berg et al. 1989, Harsányi & Aschenbrenner 1994, Rösch pers.comm.). Jungwirth (pers.comm.) reported, that in Austria the huchen status is better than 10–15 years ago. In the rivers Drau, Mur and Pielach there is about 150 km of sections with very good huchen status and natural reproduction. There is also extensive stocking of 1, 2 and 3 years old juveniles amounting annually to 10,000–20,000, 5,000–10,000 and 1,000 specimens, respectively. This production is used to stocking of the rivers Danube, Mur, Drau, Pielach as well as the Inn and the Enns. Huchen catch statistics are not available. Jungwirth only mentioned, that in the rivers Drau and Mur annual catches are 50–60 and 30 large huchens, respectively. In Slovenia the rivers Mura (=Mur), Drava (=Drau), Sava, Savinja, Krka and Kolpa were known as the good huchen rivers. At present the huchen is extinct in the Mura and in other rivers the sections inhabited by the species are remarkably shorter than before. Also the population density of the huchen significantly decreased. In the Krka river, for instance, 60–65 mating huchens in the Soteska spawning ground could be counted in the past but today the number of spawners dropped to 5–6. Povź & Sket (1990) evaluate its status in the water bodies of Slovenia as endangered and vulnerable. The huchen stock in the rivers is maintained by stocking (Povź & Sket 1990, Skalin 1994). We have no information on the situation in other countries of the former Yugoslavia, but it is hardly better than elsewhere. From Romania we have reports by Miron (1994) and Bănărescu (pers.comm.). According to the first author, there were formerly 16 rivers in Romania with the huchen stock. At present their number dropped to three, i.e. 18.8% of the former number. During 1961–1979, 13 other rivers were stocked with huchen but acclimatization (probably also naturalisation) appeared only in 6 (46%), the neg- ative one in 4 (31%) and there are no data for other three rivers (23%). According to Bănărescu the huchen in Romania underwent a numerical decline, but is not in danger of extinction. The huchen is also present in some man-made lakes as is the Bicaz Lake ( on Bistricza River) its spawning however, is limited to tributary streams. An extensive stocking program was adopted, but its success depends on the water quality of the rivers and especially on hydraulic engineering, as the program for damming Romanian rivers seems to expands significantly. In Slovakia, the range of this species has considerably decreased too (Holčík 1990, Holčík et al. 1988). Some fifty years ago the huchen inhabited more than 1000 km of rivers in Slovakia. At present the huchen disappeared from 48% of the length of all streams in which it occurred in the past, it is rare in 12% and common in 40% of the total length of the streams. Analysis of historical records indicates that the population density of the huchen was formerly relatively high, supporting catches of up to 20 huchen of 3–30 kg in weight within a day at the same place. Recent observations in Slovakian rivers indicate that in spite of some protective measures like the legal restrictions, involving the bag and size limits and the closed season along with stocking, establishment of a reserve, the huchen in Slova- kia is steadily decreasing. As it follows from the statistical data the catches of huchen shows a decreasing trend in numbers: the mean catch in periods 1954–1969, 1970–1978, 1979–1989 and in 1990–1995 was 154, 112, 92 and 54 specimens of the huchen, respectively. The increasing mean individual weight in these periods shows the reverse trend as it rose from 5.35 kg to 5.94, 6.67 and 7.3 kg, respectively. This indicates, that the population of huchen in the rivers of Slovakia becomes older. In other words both the natural reproduction of the huchen and its stocking are not sufficient enough to compensate its mortality. Recently Holčík (1997) suggested that if the observed decreasing trend continues, in 2017 the last huchen will be taken in Slovakia. Status of the huchen

184 in Poland was recently reported by Witkowski & Kowalewski (1994). Here the natural occurrence of the huchen was limited to two streams only, the Czarna Orawa and Czadeczka, belonging to the Danube river basin. Its density there was rather low as both represented the upper range of its natural occurrence. At the beginning of the 50’s the huchen disappeared from the Czadeczka stream because of the pollution and after the construction of the Orava dam in the territory of Slovakia and subsequent construction of weirs in the Czarna Orawa river the occurrence of the huchen in the Czarna Orawa was reduced to 8–10 km only. Although the Polish stocking of the Dunajec, Poprad, Skawa, Sola and Raba rivers was successful and despite the occurrence of the huchen in about 300 km of streams, the general decrease of this valuable species in the Danube basin could not be reversed. Generally, the present occurrence of the huchen is no longer continuous in many places, as it was in the past, and these are often but isolated localities. As in other salmonids reasons for the decline is the denaturalization of the huchen habitat caused by industrial development and, later, by intensive large-scale agriculture. Destructive factors include the canalisation of rivers, construction of dams, the release of industrial waste waters and municipal sewage, eutrophication, deforestation and expansion of arable land. Overfishing, including poach- ing, is only a secondary factor, as fishing for the huchen requires some experience and special equipment. This factor had more effect before World War II, when legal restrictions were very loose, allowing anglers to catch unlimited bags of partly immature fish, and the fishing season lasted 9 months. Considering all these facts the present status of this valuable fish has to be evaluated as critically endangered.

A c k n o w l e d g e m e n t s This paper would never been completed without the generous help of P. Bănărescu (Bucarest, Romania), R. Suciu (Tulcea, Romania), A. Jagdsch (Scharfling, Austria), T. Jungwirth (Vienna, Austria), R. Rösch (Langenargen, Germany), and J. Wanzenböck (Mondsee, Austria) who supplied information on the recent status of particular species of salmonids in their countries. M. Kottelat (Cornol, Switzerland), and P. Ráb (Liběchov, Czech Republic) are warmly acknowledged for their critical comments, suggestions and notes, and K. Lohniský (Hradec Králové, Czech Republic) for supply of some literature. I am grateful to J. Fott, D. Král (Praha, Czech Republic) and an anonymous reviewer for their comments.

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188 Acta Soc. Zool. Bohem. 66: 189–203, 2002 ISSN 1211-376X

Effects of acid atmospheric deposition on chemistry and benthic macroinvertebrates of forest streams in the Brdy Mts (Czech Republic)

Jakub HORECKÝ1), Evžen STUCHLÍK1), Pavel CHVOJKA2), Peter BITUŠÍK3), Marek LIŠKA4), Petra PŠENÁKOVÁ1) & Jan ŠPAČEK5)

1) Department of Hydrobiology, Charles University, Viničná 7, CZ–128 44 Praha 2, Czech Republic; e-mail: [email protected] 2) Department of Entomology, National Museum, Kunratice 1, CZ–148 00 Praha 4, Czech Republic 3) Faculty of Ecology and Environmental Sciences, Technical University in Zvolen, Kolpašská 9B, SK–969 01 Banská Štiavnica, Slovakia 4) Vltava River Authority, Holečkova 8, CZ–150 24 Praha 5, Czech Republic 5) Labe River Authority, Víta Nejedlého 951, CZ–500 03 Hradec Králové, Czech Republic

Received May 10, 2002; accepted September 3, 2002 Published November 4, 2002

Abstract. Water chemistry and macroinvertebrates of 8 streams in the Brdy Mts (Central Bohemia) differing in pH value were studied during a synoptic survey in December 1997. Together 73 macroinvertebrate taxa were identified, varying in number from 9–25 at sites of critical pH (3.8–4.3), contrary to 25–28 taxa at non-acidified sites (pH around 6.7). The fauna of streams was dominated by Chironomidae (Diptera) and Plecoptera, Trichoptera were less abundant. In three strongly acidified streams the predominance of Plecoptera exceeded 50% of all macroinvertebrates. The absence of some aquatic insects (like e.g. Ephemeroptera, some Trichoptera, most Diptera, and some Plecoptera) at sites with pH < 4.8 is discussed. The streams were classified according to their macroinvertebrate communities, with use of the Jaccard index of similarity. Symposiocladius lignicola (Kieffer, 1915) (Diptera: Chironomidae) is reported from Bohemia for the first time. Acidification, running waters, winter season, water chemistry, benthic fauna, macroinvertebrates, Czech Republic, Palaearctic region

INTRODUCTION The majority of the regional knowledge concerning processes of anthropogenic surface water acidification and its effects on biota is associated with the studies in the mountains on the borders of the former Czechoslovakia. The high mountain lakes in the Tatra Mts (Kopáček et al. 2000), the forest lakes in the Bohemian Forest (Veselý et al. 1998, Vrba et al. 2002), mountain drinking water reservoirs in the Jizera Mts (Stuchlík et al. 1997) and some streams in the Ore Mts (Krám & Hruška 1994) have been intensively studied for more than 20 years, providing detailed information about the impact of acid deposition on freshwater ecosystems. The response of plankton communities to pH changes was investigated, including the response to oligotrophication and the toxic role of aluminium in particular (Fott et al. 1994). The Brdy Mts situated in Central Bohemia have been historically known as an area rich in large peat bogs, but their sensitivity to acid deposition was not elucidated until a detailed water chemistry survey performed in 1984 (Veselý & Majer 1996). Surface waters of this area, represented mostly by brooks and drinking water reservoirs, exhibit mean pH values lower than 5.5, indicating

This contribution is dedicated to Doc. RNDr. Jaroslav Hrbáček DrSc., upon the occasion of the 80th anniversary of his birthday (12th May 1921).

189 that the Brdy Mts are among the regions of the Czech Republic which were the most intensively impacted by acid atmospheric deposition (Veselý & Majer 1998). While the effect of acidification on the macroinvertebrates of running waters in Europe and North America is generally well documented (e.g., Hall & Ide 1987, Weatherley et al. 1989, Mulhol- land et al. 1992, Herrmann et al. 1993, Guerold et al. 1995, Lien et al. 1996, Orendt 1998, Szczęsny 1998), there is a lack of such information from the Czech Republic and only several limited studies have been published so far (Růžičková 1998, Scheibová & Helešic 1999). Our knowledge on the benthic invertebrate fauna of the Brdy Mts is rather fragmentary, as the possibility of field research has been limited due to the existence of a military area in this region since 1926. One of the first records of the Brdy Mts freshwater organisms were presented at the

Fig. 1. Stream system of the Brdy Mts with the sampling sites. ⊗ – sampling site, triangle – Nepomuk precipitation station.

190 beginning of the 20th century by Roubal & Štorkán (1924). Basic information on the fauna of Ephemeroptera, Plecoptera and Trichoptera were obtained thanks to long-term research of several streams in the Brdy Mts (mainly at lower altitudes) in the late 1950s (Křelinová 1962, Novák 1962, pers. comm., Landa & Soldán 1989) and only a single site was sampled in the mid-1990s again (Soldán et al. 1998). Results of a hydrobiological study directed to small streams in the central part of the Brdy Mts including a brief list of macroinvertebrate genera were published by Pivnička et al. (1993). The main aim of this pilot study is to recognise the impact of acid atmospheric deposition on water chemistry, species composition and diversity of benthic fauna in several brooks of these mountains .

SITES AND METHODS

Study area The Brdy Mts (49° 32’ N, 13° 42’ E – 49° 50’ N, 14° 05’ E) represent the largest forested complex in the central part of the Czech Republic being situated in the Labe basin, about 50 km SW of Prague (Fig. 1). The maximum altitude of the mountain range is 864.9 m a. s. l. and the altitude of our study sites ranges from 470–685 m a. s. l. (according to base maps 1:50 000 – Mašek 1990). The Brdy Mts are covered mostly by spruce (Picea abies) forests and peat bogs are frequent in spring areas. The geology of the Brdy Mts is dominated by cambric sandstone, conglomerates, and quartzites. These rocks, with a low content of calcium and other nutrients, form nutrient-poor brown soils that tend to form high moor bogs at the highest flat altitudes. Brown soils relatively rich in nutrients occur locally, especially in the north-west mountain part where late Variscan granodiorites and diabase vulcanites encroach. The southern part contains Middle Proterozoic shales and greywackes with numerous phthanitic intercalations (Petříček & Dejmal 1998, Havlíček 1986, Mašek, 1990). Eight sites comparable in vegetation but varying in stream size, pH and altitude were selected on the following brooks: Voldušský (VOL), Červený (CER), Mourový (MOU), Reserva (RES), Třítrubecký (TRI), Kotelský (KOT), Smolivecký (SMO) and Litavka (LIT) (Tab. 1, Fig. 1). Although spruce forest covers most of the catchments of all brooks, none of them is typical brown water. The geology of catchments of the studied brooks, with the exception of Voldušský brook and Kotelský brook, is similar to the general characteristics of the Brdy Mts. Intercalations of shales and larger areas of basalt must be emphasised in the case of Voldušský brook and Kotelský brook, respectively. The sampling site at Červený brook is situated below a small fishpond, and, consequently, some liming effect may occur since the upper part of the catchment is strongly acidified (Stuchlík unpubl. data). Occasional liming is performed in the catchment of Litavka brook due to water quality concerns in a drinking water reservoir closely downstream the sampling site (Kulina 2000). The lowest discharge during the sampling time was registered at Smolivecký brook, which is of special character, since its catchment was altered by forest-drainage measures. Sampling and analytical methods The investigation was carried out on 13th December 1997. Water samples were taken prior to invertebrate ones. All analyses were conducted in the analytical laboratory of the Hydrobiological station “Velký Pálenec” near Blatná (Faculty of Science, Charles University). Conductivity was measured by conductometer CDM (Radiom- eter, France), pH was recorded at the beginning of determination of alkalinity by Gran titration on the automatic titrator TIM 900 (Radiometer, France), and the concentration of major ions was analysed by ion chromatogra- phy (Thermo Separation Products, USA). The laboratory participates in regular international intercalibration runs organised by NIVA, Oslo, Norway and the AQUACON project by CNR-ISE, Verbania-Pallanza, Italy. Precipi- tation chemistry was based on data from the Nepomuk precipitation station operated by the Institute for Forest Ecosystems Research (IFER) and published in the Tabular Survey by the Czech Hydrometeorological Institute (Fiala et al. 1999). Benthic macroinvertebrates were collected by kick sampling (net mesh size 0.5 mm) for 5 minutes per site from riffles with stony or stony-gravely substratum within a 10-m stretch, and preserved in 80 % alcohol. Invertebrates were identified to species or generic level, if possible, according to keys by Hrabě (1979), Rozkošný (1980), Wiederholm (1983), Losos (1996), Reusch & Oosterbroek (1997), Thomas (1997), Waringer & Graf (1997), Krno (1998), Zahrádková & Soldán (1998), Bitušík (2000) and Knoz (2001).

191 0.3 1 cambrica cf. throughfall 0.2 ervený Voldušský 1 Č Nemoura 1) Nepomuk 0.7 2 762 752 595 Mourový December 1997) and precipitation th 0.4 0.4 0.4 0.4 0.4 December 1997. th 1 1 1 1 1 oldušský Kotelský 13.8 ervený V 4 Č Smolivecký 0.4 Litavka Litavka Klabava 1 4.5 Kotelský Mourový Skalice 2 ítrubecký Litavka ř 1.5 1.5 3.0 1.5 RES TRI L I T SMO KOT MOU CER VOL 1 1 2 1 N% N% N% N% N% N% N% N% Reserva T Category III Category II Category I ítrubecký Litavka Smolivecký Despax, 1934 ř 00000000397498576 62264721000 uncinata 125997 121 843 112 242 140 445 145 452 128 836 162 388 112 432 20 431 20 452 50 876 4.281.201.06 3.271.08 1.42 1.151.88 3.68 1.17 1.97 1.69 2.20 1.41 4.12 2.62 1.52 2.06 5.82 1.72 3.38 2.17 2.07 5.78 1.39 2.14 1.47 2.14 6.11 1.20 2.84 1.99 1.86 15.67 1.05 12.69 3.38 2.45 0.13 1.50 0.02 0.13 2.56 0.21 0.05 0.04 0.20 0.23 1.02 0.16 0.18 0.35 0.60 2.76 1.44 107.3 83.8 83.7 78.8 79.920.90 23.12 64.8 20.18 68.9 23.90 165.6 22.10 19.2 24.68 18.6 22.43 67.2 17.58 1.60 1.87 8.15 49°42’ 27” 49°41’ 53”13°49’ 13” 49°39’ 50” 13°48’ 30” 49°34’ 24”Klabava 13°53’ 17” 49°35’ 41” 13°45’ 45” 49°45’ 00” 13°46’ 22” 49°46’ 53” Klabava 13°50’ 00” 49°48’ 40” 13°53’ 11” 13°39’ 56” Litavka Lomnice 33’’ 39’ 49° 09” 49’ 13° 33211232 –130.6 –70.5 –54.0 –41.4 –6.2 7.1 120.3 203.7 – – – cf. –1 –1 –1 –1 –1 –1 –1 –1 –1 –1 –1 –1 –1 Nemoura (Grube, 1879) µS cm mg l mg l mg l mg l µg l mg l mg l (Savigny, 1826) (Savigny,

2) Pictet, 1845 sp. sp. -N µg l -N-N µg l µg l – – – 2– 4 2 3 2+ 4 + 2+ – 20 + – Mg Na K F NO Cl SO pHAlk µeq l 3.9 4.2 4.3 4.4 4.9 5.3 6.6 6.7 4.6 4.6 4.1 NH Tab. 1. Sampling site description, water chemistry of studied brooks at the sampling sites (the left part table, 13 Tab. of 8 sampling sites in the Brdy Mts found on 13 (N) and relative (%) abundance of organisms Total 2. Tab. OLIGOCHAETA Bythonomus lemani Lumbriculus Lumbriculidae gen. sp. EPHEMEROPTERA Baetis rhodani Stylodrilus Naididae gen. sp. Eiseniella tetraedra Oligochaeta gen. sp. Brook Reserva T Ca NO K Code RES TRI LIT SMO KOT MOU CER VOL wet only bulk AltitudeLatitudeLongitudeRiver basin l. s. a. m N E 610 570 650 685 665 510 470 480 860 Max. widthDist. from sourcePrecipitation km m y mm 4.3 5.6 2.1 1.5 0.5 4.7 7.5 1.7 chemistry from the Nepomuk precipitation station (annual weighted mean 1997/98, Fiala et al. 1999) (Stephens, 1836);

192 1.2 1.5 6.2 1.5 7.3 0.3 0.3 0.3 1.2 2.9 0.3 10.3 16.1 1 0 25 4 5 5 1 1 1 4 1 ) 2 35 55 1 1 0.2 0.7 0.4 1.8 0.2 0.7 0.2 8.2 0.4 0.2 0.2 0.2 0.2 0.7 0.2 0.2 13.3 14.4 60 1 3 2 8 1 3 1 2 1 1 1 1 3 1 1 ) 37 65 2 0.3 7.4 1.0 5.4 5.4 5.7 7.8 0.7 1.7 2.4 10.1 3 6 7 ) 1 2 5 7 22 1 20 1 23 30 2 0.4 0.8 0.4 7.8 0.8 6.2 3.1 0.4 1.6 0.4 4.7 0.4 1.6 0.8 0.8 18.6 6 2 1 2 1 2 8 1 4 1 1 4 2 2 20 48 1 1 3.4 3.4 13.8 13.8 4 1 4 1 0.7 1.1 0.4 0.4 0.4 3.2 0.7 8.2 1.1 1.1 43.6 27.3 23 2 3 1 1 1 9 2 3 3 1 77 23 ) 2 2.3 6.8 2.3 4.5 4.5 4.5 56.8 11.4 3 ) 1 1 2 2 5 2 25 2 9.1 4.5 1.5 9.1 3.0 4.5 7.6 1.5 4.5 3.0 19.7 13.6 3 3 ) 6 1 6 2 3 9 5 1 3 2 1 1 (Stephens, 1835) (Pictet, 1841) (Curtis, 1834) (Latreille, 1805) (Linnaeus, 1758) (Scopoli, 1763) (Morton, 1894) McLachlan, 1884 (Linnaeus, 1758) Illies, 1954 (Pictet, 1841) Kimmins, 1942 Pictet, 1834 species group (Kolenati, 1859) Morton, 1894 (Stephens, 1836) Pictet, 1834 Aubert, 1949 Klapálek, 1900 (Stephens, 1837) Aubert, 1957 Kempny, 1899 Kempny, (Linnaeus, 1758) Pictet, 1836 juv.

sp. rivosa Kempny, 1899 Kempny, sp. juv. (Olivier, 1811) sp. sp. juv. sp. cf.

spp. .) spp. P ( Ecdyonurus torrentis Rhithrogena iridina Paraleptophlebia submarginata PLECOPTERA Amphinemura borealis Leptophlebia vespertina Amphinemura Nemoura avicularis Nemoura cambrica Nemoura flexuosa Nemoura Protonemura auberti Protonemura meyeri Protonemura Leuctra prima Diura bicaudata Siphonoperla torrentium ODONATA Cordulegaster annulatus Potamophylax Rhyacophila vulgaris Nemurella pictetii Leuctra hippopus Leuctra rauscheri MEGALOPTERA Sialis fuliginosa TRICHOPTERA Rhyacophila tristis Plectrocnemia conspersa Hydropsyche Drusus annulatus Limnephilidae gen. sp. juv. Sericostoma Leuctra nigra Odontocerum albicorne Hydropsyche saxonica DIPTERA – excl. Chironomidae Dicranota Pedicia

193 0.3 0.3 1.5 0.3 0.3 2.6 0.3 0.9 0.9 0.9 42.2 1 1 5 1 1 9 1 3 3 3 44 1 4.0 5.8 0.4 2.2 1.1 0.2 0.4 2.0 41.2 ervený Voldušský 8 0 86 2 5 1 2 9 1 26 1 Č 1 0.3 1.0 3.4 2.0 2.0 41.2 0 22 1 3 6 6 1 Mourový 1 0.4 0.4 6.6 0.4 1.2 1.6 0.8 4.7 0.8 0.4 32.6 7 2 1 1 1 3 4 2 2 1 84 1 1 Kotelský 3.4 6.9 17.2 24.1 1 2 5 7 Smolivecký 0.4 0.4 0.4 1.1 0.4 0.4 0.4 3.5 0.4 2.8 0.4 1.4 1 1 1 0 3 1 1 1 1 8 1 4 1 2.3 1 ítrubecký Litavka ř 1.5 4.5 1.5 1.5 1.5 RES TRI L I T SMO KOT MOU CER VOL 1 3 1 1 1 N% N% N% N% N% N% N% N% Reserva T (Zetterstedt, 1838) (Walker, 1856) (Walker, (Goetghebuer, 1940) (Goetghebuer, (Kieffer, 1915) (Kieffer, 1909) ) spp. (Schrank, 1803) species group (Germar, 1834) (imago) (Goetghebuer, 1936) (Maigen, 1818) species group (Edwards, 1929) (Fabricius, 1781) (Meigen, 1830) sp. rectangularis rectangularis spp. sp. sp. sp.

spp. sp. .) cf. sp. (larva) sp. sp. Nevermannia S ( ( spp. (larvae) sp. (larva) sp. (larva) sp. sp. spp. (larvae) Tot. ind. (N) ind. Tot. 66 44 282 29 258 296 452 341 Orthocladiinae gen. sp. Micropsectra Tanytarsus Elmis Limnius COLEOPTERA Agabus Tvetenia calvescens Tvetenia discoloripes Polypedilum laetum Polypedilum scalaenum Deronectes platynotus Helophorus Helodes Symposiocladius lignicola Tokunagaia Limnophyes Rheocricotopus fuscipes Heterotrissocladius marcidus marcidus Heterotrissocladius Brillia modesta Trissopelopia Trissopelopia Macropelopia Simulium Ibisia marginata Wiedemannia DIPTERA – Chironomidae Apsectrotanypus trifascipennis Conchapelopia Tab. 2. continuation Tab. Bezzia Prosimulium Simulium Tipula Tipula

194 Biological classification of the sites was based on the calculation of Jaccard’s index (Ludwig & Reynolds 1988). Then, the Ward’s method of linkage was used to construct a dendrogram. Statistical analyses were performed using STATISTICA software (StatSoft, Inc., USA). RESULTS Water chemistry All studied sites represented poorly buffered soft water brooks very sensitive to acid atmospheric deposition, with ion compositions dominated by sulphate, calcium and magnesium (Tab. 1). The brooks were divided into three distinct categories according to their water chemistry (mainly pH, alkalinity, and calcium and magnesium concentrations) as follows: Category I was defined as pH > 5.8 (mean Gran alkalinity of 162 µeq l–1, and mean concentration of Ca2+ and Mg2+ of 10.8 and 5.33 mg l–1, respectively). Category II was defined as pH 4.8–5.8 (mean alkalinity of 0 µeq l–1, mean concentration of Ca2+ and Mg2+ of 5.80 and 2.86 mg l–1, respectively). Category III was defined as pH <4.8 (mean alkalinity of –74 µeq l–1, mean concentrations of Ca2+ and Mg2+ of 3.84 and 1.80 mg l–1, respectively). The concentration of sodium varied from 1.06 to 3.38 mg l–1, exhibiting a similar relationship to pH as does calcium and magnesium. Nitrates did not show any significant correla- tion with pH varying widely between 242 and 997 µg N l–1. Concentrations of potassium, fluoride, chloride and sulphate were almost identical at all the sites studied, averaging of 1.32, 0.13, 2.08 and 21.86 mg l–1, respectively. Data on chemistry and amount of precipitation (wet only, bulk, and throughfall) at the Nepomuk precipitation station, situated in the central part of the Brdy Mts (Fig. 1), are summarised in Tab. 1. The ionic pool was dominated by sulphate, nitrate, ammonia and hydrogen in all types of samples. Ionic concentrations were similar in wet only and bulk samples, and substantially lower than the throughfall values. This difference was more significant for sulphate (4.85 and 1.22 mg m–2 yr–1 for throughfall and bulk deposition, respectively) than for dissolved inorganic nitrogen (DIN = ammonia- plus nitrate-nitrogen; 0.86 vs. 0.63 mg m–2 yr–1). The throughfall deposition was more relevant for the totally forested catchments of all investigated brooks. Macroinvertebrates Altogether 73 macroinvertebrate taxa were identified in the studied brooks in the Brdy Mts (Tab. 2). The number of taxa (S) at particular sites (Tab. 3) showed a positive pH dependence. While 25– 28 and 18–32 taxa were found in categories I and II, respectively, from 9–25 (mean of 16) taxa were present in the sites of category III. The Shannon-Weaver index (H’) did not reveal any dependence on pH value in the investigated brooks (Fig. 2). Oligochaeta were found at sites with pH below 5.0, whereas Ephemeroptera (mainly Baetis rhodani, Ecdyonurus torrentis and Leptophlebia vespertina) only at sites of categories I and II (Fig. 3). Larvae of stoneflies (Plecoptera) were abundant at all sites and the most abundant in Třítrubecký, Litavka and Reserva brooks. This order was dominated by larvae of families Nemour- idae (Nemoura avicularis, N. cambrica, Protonemura auberti, P. meyeri and Amphinemura borealis) and Leuctridae (Leuctra nigra and L. hippopus). Diura bicaudata (Perlodidae) occurred in brooks of category III only. One specimen of Odonata (Cordulegaster annulatus) was found at the site on Voldušský brook. The order Megaloptera occurred at low densities at four sites, independent of pH. Trichoptera larvae formed 30 % of the total fauna of Reserva brook and 10 % of Třítrubecký brook, but were less abundant elsewhere (Fig. 3). Plectrocnemia conspersa was present at nearly all sites (except for Třítrubecký brook), while Drusus annulatus was found at sites of category III and Rhyacophilidae (Rhyacophila vulgaris group and R. tristis) occurred irrespective of pH. Larvae of Diptera dominated all sites of categories I and II and in Smolivecký brook. Larvae of Brillia modesta and Micropsectra spp. (Chironomidae) occurred independent of acidity at nearly all sites, as did larvae of Simuliidae and Limoniidae (Dicranota sp.), representing

195 other groups of the order Diptera. Records of Symposiocladius lignicola, Rheocricotopus fuscipes, Tvetenia discoloripes and T. calvescens are published from Bohemia for the first time. Consid- erable density of Coleoptera was found at Kotelský brook only (see Tab. 2) The dendrogram of site dissimilarities (Fig. 4) shows two distinct groups – the first one consists of the four sites of category III (Litavka, Smolivecký, Třítrubecký and Reserva brooks) and the second one of the remaining sites that cannot be further distinguished.

DISCUSSION The low pH and high concentrations of sulphate and DIN in all types of precipitation suggest the atmospheric deposition to be the major source of acidity in the brooks studied. The observed extremely low (<0 µeq l–1) values of Gran alkalinity and low concentrations of calcium and magnesium in the brooks of categories II and III are characteristics for the areas with limited alkalinity sources (low weathering and depleted base saturation of soils), exposed to the elevated acid deposition (e. g., Psenner & Catalan 1994). Such waters are usually rich in concentrations of ionic aluminium, which is potentially toxic for aquatic organisms (e. g., Driscoll & Postek 1995).

Fig. 2. Taxa richness and diversity within the three groups of brooks of different acidity (means and ranges with number of samples). S – total number of taxa, H’ – Shannon-Weaver index.

196 Tab. 3. Number of taxa per taxonomic group from Tab. 2

RES TRI L I T SMO KOT MOU CER VOL Reserva Třítrubecký Litavka Smolivecký Kotelský Mourový Červený Voldušský Oligochaeta 4 1 1 1 4 – – – Ephemeroptera – – – – 4 2 3 3 Plecoptera 6 5 7 2 7 7 9 5 Odonata – – – – – – – 1 Megaloptera 1 – – – 1 – 1 1 Trichoptera 4 2 3 1 4 2 5 4 Diptera 5 1 12 5 10 6 10 10 Coleoptera 1 1 2 – 2 1 – 1 Suma 2 1 1 0 2 5 9 3 2 1 8 2 8 2 5

Even though aluminium was not analysed in this survey, our later detailed study on Litavka brook chemistry confirmed the presence of high concentrations of reactive aluminium (up to 2000 µg l–1; Kulina 2000, Stuchlík et al. 2000). Labile aluminium, most toxic to water organisms, constitut- ed up to 70 % of that aluminium pool. This high ratio of labile to reactive aluminium in the category

Fig. 3. Relative numbers of macroinvertebrate taxonomical groups (%, OLI–Oligochaeta, EPH–Ephemeroptera, PLE–Plecoptera, MEG–Megaloptera, TRI–Trichoptera, DIP–Diptera excluding Chironomidae, CHI–Chirono- midae, COL–Coleoptera). Site abbreviations as in Tab. 1.

197 III brooks clearly indicates that DOC concentrations are not high enough to ameliorate significantly the toxic effects of aluminium on macroinvertebrates (Fott 1994). Atmospheric input of sulphate and DIN in the Brdy Mts is within a typical range published for the other forest regions in the Czech Republic (Fiala et al. 1999). The observed sulphate concentrations in the brooks studied are substantially higher than could be expected from just an evapotran- spiration effect, suggesting some additional sulphate sources in their catchments. Such a situation is typical for the ecosystems recovering from acidification and is associated with a wash-out of sulphate accumulated in soils during previous decades of its elevated deposition (Alewell 2000, Prechtel et al. 2001). This washing out may last several decades, as predicted for the geographically adjacent mountain areas (Kopáček et al. 2001, Hruška et al. in press). In contrast to sulphate, nitrate concentrations in the brooks are low, indicating that the forest ecosystem of the Brdy Mts is probably in the early stage of nitrogen saturation according to Stoddard (1994). The elevated export of aluminium from a catchment usually accompanies leaching of strong acid anions from the acidified soils. Due to the dominant role of sulphate in the total pool of strong acid anions in the brooks studied, the future extent of aluminium concentrations, as well as the associated toxicity will predominantly reflect the fate of sulphur accumulated in soils. Consequently, the elevated aluminium concentrations can be expected in the brooks also for the next several decades despite a >80 % decrease in sulphate emission in the Central Europe (Kopáček et al. in press). Comparable values of conservative ions (e.g., sulphate and chloride) in the brooks (Tab. 1) suggest that even the limited data based on a single synoptic survey can provide a reasonable basis for classification of the water acidity status. The highest total abundance of water macroinvertebrates was recorded in all streams of categories I and II and also in Litavka brook. The low numbers of individuals in Reserva and Třítrubecký brooks may be explained not only by the effects associated with acidification, but also by other environmental factors, as the influence of acidification on aquatic macroinvertebrate abundance has not been explicitly proven (Herrmann et al. 1993). Mulholland et al. (1992) consider the densities of shredder and collector-gather macroinvertebrates to be correlated rather to benthic organic matter than to pH. In the case of Smolivecký brook, the total abundance might also be poor due to its drainage ditch character. Most of the collected organisms were insects, of which Plecoptera and Diptera were the most abundant. A comparison of the composition of macroinvertebrate communities of the streams studied in the Brdy Mts shows that number of invertebrate taxa is reduced as a consequence of acidification. A decrease in species richness and diversity, and changes of composition of functional feeding groups in acidified streams, are well documented effects of acidification (e.g., Økland & Økland 1986, Szczęsny 1990, Guerold et al. 1993, Herrmann et al. 1993, Dangles & Guerold 2000). This feature results from the disappearance of Ephemeroptera, Mollusca and Crustacea, and reduced richness of other groups (Diptera, Trichoptera, Coleoptera, Plecop- tera, see e. g., Raddum & Fjellheim 1984, Weatherley et al. 1989, Guerold et al. 1995, Szczęsny 1998). Differences in tolerance to acid waters can be found within stonefly (Plecoptera) larvae, among which Siphonoperla torrentium is considered to be moderately sensitive (Braukmann 1994), as is Diura bicaudata (occurrence at pH > 5 according to Fjellheim & Raddum 1990). Other authors (Braukmann 1994, Soldán et al. 1998), however, consider the latter species as acid-tolerant. This species was already reported from the Brdy Mts by Křelinová (1962) and Pivnička et al. (1993), and found ourselves in 1997 in the most acid brooks: Reserva, Třítrubecký and Litavka. Leuctra hippopus and Nemoura avicularis appeared to be associated with waters of pH above 4.8 in the study area, although they could be expected at lower pH values as well (Fjellheim & Raddum 1990); Scheibová & Helešic (1999) found N. avicularis at a minimum pH of 5.5. Amphinemura borealis, Nemurella pictetii, Leuctra nigra and L. rauscheri belong to the extremely acid-tolerant stone-

198 flies (Fjellheim & Raddum 1990, Braukmann 1994), which is in agreement with our results. The occurrence of Amphinemura borealis and Diura bicaudata, vulnerable and endangered species in the Czech Republic (Soldán et al. 1998), deserve attention from the faunistic point of view. Heterotrissocladius marcidus, an acid-tolerant chironomid species (Orendt 1999), occurred at relatively high abundance in acid Smolivecký brook. The presence of Apsectrotanypus trifascipennis larva in Litavka brook (pH 4.3) is in contradiction with its extreme acid-sensitivity supposed by Orendt (1999), though in this case it can be associated with an imbalance of the acidity state as a consequence of liming. The increase of Micropsectra spp. abundance with increasing pH in investigated streams might reflect its moderate sensitivity to acid conditions. The record of Sym- posiocladius lignicola is interesting from the faunistic point of view; this species, so far known from Moravia and Slovakia (Bitušík & Losos 1997), is reported from Bohemia for the first time. Due to specific morphological features of its larva, this species is easily distinguishable from other species of the subfamily Orthocladiinae (Bitušík 2000). The occurrence of larvae of the Poly- pedilum (Tripodura) scalaenum group in Bohemia was shown only recently (Chalupová & Matě- na 2002). Other species recorded not listed in Bitušík & Losos (1997), namely Rheocricotopus fuscipes, Tvetenia discoloripes and T. calvescens, occur in the Czech Republic frequently (Matě- na, pers. comm.).

Fig. 4. Biological classification of sites based on Jaccard’s index of similarity; recorded water pH is indicated bellow. Site abbreviations as in Tab. 1.

199 Rhyacophila larvae (Trichoptera) are generally regarded as acid-tolerant, with the exception of R. tristis which is considered more sensitive (Guerold et al. 1993, 1995, Braukmann 1994), preferring waters with pH 5.4–7.4 (Novák 1962). Surprisingly, R. tristis was found in Reserva brook at pH 3.9. Plectrocnemia conpersa exhibits a great tolerance to acidification as has been well documented earlier (e. g., Fjellheim & Raddum 1990, Scheibová & Helešic 1999). This most abundant caddisfly species of streams in the Brdy Mts occurs independent of acidity. Drusus annulatus was recorded only in streams of category III; larvae of this common mountain species of the Czech Republic also inhabit streams with low pH in other acidified regions (Horecký unpubl. data). This species was reported as acid-tolerant e.g. from the Vosges Mts (Guerold et al. 1995), although Szczęsny (1990, 1998) did not find it in acidified streams of the West Carpathians. The majority of Ephemeroptera species are strongly acid-sensitive and therefore become extinct in waters below pH 5–5.5 (Økland & Økland 1986, Herrmann et al. 1993, Havas & Rosseland 1995). In the investigated streams, mayflies were recorded at sites with pH > 4.8. Baetis rhodani, considered a potential indicator species of non-acidified waters (Larsen et al. 1996) and extremely acid-sensitive (e.g. Scheibová & Helešic 1999), was found at pH around 5 in the Brdy Mts, which better correspond to Engblom & Lingdell (1984), who mention this species as moderately acid- tolerant showing somewhat lower pH tolerance limits (4.5). On the other hand, we recorded Lep- tophlebia vespertina only in streams of categories I and II although this species is known as extremely acid-tolerant (Larsen et al. 1996) and Engblom & Lingdell (1984) report survival of this species up to pH 3.5. Its absence at sites with the lowest pH might be the consequence of unfavourable flow conditions there, since L. vespertina larvae prefer habitats with low current speed or pools (Soldán et al. 1998). The permanent fauna is represented only by Oligochaeta found in streams with pH < 5. Since Oligochaeta belong to acid-tolerant organisms often forming the major component of the bottom fauna under acidic conditions (Weatherley et al. 1989, Guerold et al. 1995), their absence or low abundance can reflect the absence of fine sediments at the sampled sites or the sampling procedure. Aquatic Mollusca and Crustacea, generally considered acid-sensitive (e. g., Økland & Øk- land 1986), were not found at the studied sites, but occur in more alkaline waters of the Brdy Mts (Roubal & Štorkán 1924, Pivnička et al. 1993, Horecký unpubl. data). The biological classification corresponds well with characteristics based on water chemistry data distinguishing the group of streams highly impacted by atmospheric deposition (category III). Although point liming at the Litavka catchment results in episodic extremes of water pH up to neutral or alkaline values, the site still appears to be unfavourable for mayflies, either due to pH imbalance (Kulina 2000, Stuchlík et al. 2000) or low minimum pH. On the other hand, relatively low differences in species composition of the remaining sites (categories I and II) probably represent a consequence of episodic acidification. Our results confirm the importance of biological assays, especially in the case of non-frequent water sampling.

A c k n o w l e d g e m e n t s The authors wish to thank David Hardekopf for revision of the English text, Tomáš Soldán (Institute of Entomology, Academy of Sciences of the Czech Republic, České Budějovice) for the revision of Ephemeroptera larvae, and Josef Matěna and Jiří Kopáček (Hydrobiological Institute, Academy of Sciences of the Czech Republic, České Budějovice), who made valuable comments on early draft of the manuscript.

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203 Acta Soc. Zool. Bohem. 66: 204, 2002 ISSN 1211-376X

BOOK REVIEW

BUSH A. O., FERNÁNDEZ J. C., ESCH G. W. & SEED J. R: Parasitism: The diversity and ecology of animal parasites. Cambridge: Cambridge University Press, 2001. IX+566 pages. Format 191×245 mm. Soft cover. Price Lstg 29.95. ISBN 0-521-66447-0 The authors are accredited experts affiliated with the universities and scientific societies in USA and Canada. As stated in the preface, the present book is derived from another, entitled A functional biology of parasitism (Chapman & Hall, 1993). The authors provide fundamental insights into the parasitism – the most prevalent, ubiquitous life style among organisms. Introduced are data that deal with the diversity of major eukaryotic parasites of animals considering the impact they have on their hosts. Special attention is centred upon ecological relationships of the host-parasite systems. Not omitted is basic biochemical, molecular and immunological piece of information relevant to parasitism. The volume is composed of 16 chapters divided into sections (subchapters – in number from 3 up to 12). Chapter 1 is intended to give the introduction to parasitology while discussing parasitism in historical perspective, symbiotic relationships, kinds of parasites, kinds of hosts, and ecology in an environmental context. Immunological, pathological, and biochemical data related to parasitism are outlined in chapter 2. Consequent thematic block of seven chapters (3 through 9; 265 pages = 47%) provides access to the systematics of protozoans and metazoans. In chapter 3 examined are three protozoan phyla: the Sarcomastigo- phora, Apicomplexa and Ciliophora. It is important to be mentioned that the systematics of the Protozoa is under constant revision and with the use of molecular procedures will continue to be revised for the foreseeable future. Newer classifications introduce different schemes and do not include the group Sarcomastigophora. Microsporidians are now considered to be Fungi. Chapter 4 is devoted to flatworms Platyhelminthes comprising seven taxonomical groups. It is stated here that flatworms present a diverse group showing great variability in anatomy, life history, size, and habitat – they are likely ancestors of all the metazoan phyla. Systematic classification of these parasites has changed significantly in the last decade or two because of morphological information made available by electron microscopy, the application of cladistic techniques, and molecular systematics. The classification outlined here is based on studies of Brooks and other authors in the ninethies of the past century. Chapter 5 focuses on roundworms Nematoda. It is stressed that nematodes are now recognized as perhaps the most significant metazoan parasites associated with humans. Recent advances in molecular systematics (18S rDNA sequences) may clarify the phylogenetic relationships in nematodes, nonetheless new proposals await further verification. The classification scheme used here is one of convenience based on morphological data more readily available than nucleotide sequences. In subsequent chapters 6 through 8 acanthocephalans, pentas- tomids and arthropods are analyzed. In addition to the major phyla of parasitic organisms discussed in previous chapters, in chapter 9 attention is centred upon other animal phyla that are parasitic in some stage in their life cycle. With the application of the newer molecular techniques, it is now recognized that myxosporidians Myxo- zoa, formerly classified among the Sporozoa, are not unicellular protozoans but a metazoan group. Subsequent chapters 10 through 16 take into consideration selected general phenomena of parasitism. Chapters 10 and 11 analyse population concepts and factors influencing parasite populations while giving general definitions, and describing environmental factors, distributional patterns, dynamics of population growths, density-dependent and -independent factors, regulation of parasite populations. Chapter 12 provides access to the influence of parasites on host populations: the Crofton’s approach (analysis of host-parasite systems), aggregation and regulation, epidemiological implications, non-genetic and genetic predispositions. In chapter 13 looked at is the ability of parasites to complete their life cycle. Chapter 14 gives an overview of parasite communities. In chapter 15 elucidated are biogeographical events and processes, geographical distribution of parasites and diverse aspects of ecology and applied biogeography. Final chapter 16 illuminates biological evolution. In conclusion, there is an extensive glossary (14 pages) of key terms relevant to topics discussed. Accentuated on grey background, there are separate textual boxes containing supplemental discussions and topical observations to the current text. The volume is extensively illustrated by a wealth of figures numbered separately in each chapter and composed of schematic line drawings and photographs. Featured are individual parasitic organisms, views of external and internal structural parts, various developmental stages, life cycles, functional interactions and metabolic pathways, diverse cladograms and evolutionary trees, miscellaneous diagrams, geographical maps, and selected pathological conditions in parasitized humans and animals. Moreover, tabular overviews summarizing data given in the textual part are numerous and detailed. Written in a user-friendly style, this monograph offers an original and most informative approach to the study of animal parasites of medical, veterinary as well as general zoological interest. Jindřich Jíra

204 Acta Soc. Zool. Bohem. 66: 205–212, 2002 ISSN 1211-376X

Crustaceans (Crustacea: Cladocera, Copepoda) of the Morava River Alluvium on the Slovak Territory

Marta ILLYOVÁ1) & František KUBÍČEK2)

1) Institute of Zoology, Department of Hydrobiology, Slovak Academy of Science, Dúbravská cesta 9, SK–824 06 Bratislava, Slovakia; e-mail: [email protected] 2) Faculty of Science, Masaryk University, Kotlářská 2, CZ–611 37 Brno, Czech Republic

Received July 2, 2002; accepted September 3, 2002 Published November 4, 2002

Abstract. The paper presents the first comprehensive survey of 58 Cladocera species and 38 Copepoda taxa from 15 localities of various types of arms, temporary pools and oxbows of the Morava River inundation on the Slovakian territory. Among the species found, the cladocerans Bosmina coregoni Baird, 1875, Daphnia parvula Fordyce, 1901, D. ambigua Scourfield, 1946, Pleuroxus denticulatus Birge, 1879, Moina weismanni Ishikawa, 1896 and the calanoid Eurytemora velox (Lilljeborg, 1853) are supposed to be either invaders or introduced species.Cladocerans Bosmina longirostris (O. F. Müller, 1776), Moina micrura Kurz, 1874, M. weismanni Ishikawa, 1896, the genus Daphnia and copepods of the genera Eudiaptomus and Acanthocyclops prevailed in relatively deep side arms situated in the inundation. Phytophilous assemblages of Daphnia curvirostris Eylman, 1887, Megafenestra aurita (Fischer, 1849), Mixodiaptomus kupelwieseri (Brehm, 1907), genera Simocephalus, Scapholeberis, and Acroperus dominated in waters of temporary character and shallow dead arms covered with macrovegetation. Distribution, wetlands, floodplain, pools, Crustacea, Morava River, Palaearctic region

INTRODUCTION Aquatic alluvial biotopes are often being terrestrialized. It is caused either by natural ageing or by anthropogenic intervention. The Slovak part of the Morava River floodplain, especially the inun- dated area, is the territory where the diversity of original aquatic biotopes has been preserved. Several recent studies (Adámek & Sukop 1992, Kopecký & Koudelková 1997, Sukop & Ko- pecký 1999, Kopecký et al. 1999) have been published on the Cladocera and Copepoda fauna in the upper section of the Morava River and its tributary Dyje. There is a lack of data on Cladocera and Copepoda species composition in the lower section of the Morava River on the Slovak territory, except rare Crustacea in temporary pools (Brtek 1976 and 1992). This lack is caused by prohibited access to portion of the Morava River that forms the border between Slovakia and Austria over a long period of time. Systematic monitoring of the study area began only in 1994 thanks to project on revitalisation of cut-off meanders (Štěrba 1995, Lisický et al. 1997). The result of this project is the first list of Cladocera and Copepoda species in the Morava alluvium (Illyová 1999). Our study focuses on different types of standing waters of the Morava River floodplain. Our goal is to explain the occurrence of cladocerans and copepods in the Slovak portion of the Morava River.

We dedicate this contribution to Doc. RNDr. Jaroslav Hrbáček DrSc., upon the occasion of the 80th anniversary of his birthday (12th May 1921).

205 Tab. 1. Description of study sites number of locality name of locality river km cadastre 1 meander XVIII. 65.6–66.0 Moravský Sv. Ján 2 meander XVII. 65.3–65.5 Moravský Sv. Ján 3 meander XVI. 63.5–64.0 Moravský Sv. Ján 4 meander VII. 18.9–20.6 Vysoká pri Morave 5 meander II. 11.7–12.3 Vysoká pri Morave 6 Šrek 11.5–14.5 Stupava 7 Nová Kakvica 22.8–24.7 Vysoká pri Morave 8 Rudavné jazero 51.5–52.1 Malé Leváre 9 Lepňa 57.0–57.9 Malé Leváre 10 Bezodné 13.0 Vysoká p.M. 11 Oblaz 27.0 Záhorská Ves 12 Štokrzí 49.0–50.0 Gajary 13 Bučany 61.0 Moravský Sv. Ján 14 Lantov 62.0–64.0 Moravský Sv. Ján 15 Pod Devínom 0.5 Devínska Nová Ves

STUDY AREA

Our 15 study localities (Table 1) are situated between the Moravský Svätý Ján village and the Devín village, or river km 66.0 and km 0.5, respectively, in the Záhorie lowland, Slovakia. They can be divided according to their distance from the main stream (sensu Roux et al. 1982) into three groups: 1. The former meanders of the Morava River (Localities 1, 2, 3, 4 and 5). They were permanently connected with the main channel during high discharge and correspond to the parapotamon type according to Roux et. al (1982) and Ward et al. (1995). Their depth is about 2 m. Locality 1 is in the advanced stage of terrestrialisation (Štěrba et al. 1995). Its littoral zone contain floating macrophytes (Spirodela polyrrhiza, Lemna sp.) and submersed and emergent macrophytes (Ceratophyllum demersum and Glyceria sp.), respectively. 2. Dead meanders of the Morava River (Localities 6, 7, 8 and 9) and meadow pool (15). Localities of this group are connected to the main channel only during inundation of the floodplain. They correspond to plesio- potamon of Roux et al. (1982). These localities can be further divided into subgroups: (2a) Relatively deep meanders (Localities 6–9). Their length remarkably exceeds their width and the maximum depth reaches about 2 m. Macrophytes Ceratophyllum demersum, Polygonum amphibium, Potamogeton sp., Nuphar lutea, Phragmites australis, Spirodela polyrrhiza and Lemna minor are common in this subgroup. (2b) A permanent floodplain meadow pool (Locality 15). It has a round shape, and maximum depth of 1 m. The pool is often dry in late summer and autumn. Its shore is overgrown by Phragmites australis. 3. Old meanders of Morava (Localities 10, 11, 12, 13 and 14). They are isolated from the main stream by a main dam. They correspond to paleopotamon of Roux et al. (1982). Old meanders can be divided into subgroups: (3a) Shallow temporary pools (Localities 11, 12, 13 and 14). Their depth is less than 1 m and the length exceeds width. The maximum water level is achieved during the spring, or autumn. Prevailing vegetation at these localities contains Rorippa amphibia, Schoenoplectus lacustris, Glyceria maxima and Typha sp. Tn the locality 13 at Bučany Hottonia palustris and Stratiotes aloides occured, until the pool became cattle crossing. When the water became turbid and smelled of liquid manure, the vegetation contained only Spirodela and Lemna. (3b) Relatively deep pool (Locality 10). It has an oval shape and 2.5 m depth. The original meander was most probably deepened by the gravel excavation. Its littoral zone contains Ceratophyllum demersum, Batrachium sp., Rorripa amphibia, Carex gracilis and Schoenoplectus sp.

METHODS

Samples of the cladoceran and copepod assemblages were taken using plankton net with 130–140 µm mesh. They were preserved in 4% formaldehyde. Medial zone samples were taken using vertical tows from boat or oblique tows from bank moved from bottom to surface. Littoral zone samples were taken as well.

206 Altogether 271 samples were analysed. Cladocera samples were collected from the medial and littoral zone at 34 sampling sites of 12 localities (1–9, 12, 13 and 14) during August–September, 1994. Altogether 105 oxbow samples were taken at 15 sampling sites of localities 1–5 as part of the meander revitalisation project of Štěrba et al. (1995) during 1994–95. Both Cladocera and Copepoda were studied. Samplings took place during May, July, August, October and December in 1994 and February and May in 1995. In total, 75 samples of Cladocera and Copepoda were collected from the littoral zone of 5 oxbows during 1995. They were taken at 5 sampling sites of localities 1–5. Samples were collected as part of the project of Lisický et al. (1997). Sampling took place in May, July and October. Altogether 70 Cladocera and Copepoda samples were collected from the medial and littoral zone of 10 localities during 2001. They were taken at 20 sampling sites of localities 6–15. Samples from localities 6, 9, 10 and 13 were collected during May–October. Locality 7 was sampled during May, June, September and October. Locality 11 was sampled during May and July–September. Localities 12 and 14 were sampled during May, September and October and Locality 15 was sampled during May–July. Locality 8 was sampled only once in May.

RESULTS In total, 58 Cladocera species and 38 Copepoda taxa were found in the study area (Tabs 2 and 3). They belong to three different types of environment: (1) former meanders of the Morava River, (2) dead meanders and meadow pool inside-dikes, and (3) old meanders and oxbow outside-dikes. The former meanders of the Morava River The highest number of Cladocera species, 46 taxa, was found in side arms. They represent 79% of all species found. The species Bosmina longirostris, Moina micrura and M. weismanni prevailed in the medial zone. They occurred in mass at some localities. Other pelagic species Daphnia galeata, D. ambigua, D. longispina and D. parvula were present almost at all localities. Littoral Cladocera fauna was also abundant. Sida crystallina, Pleuroxus aduncus, Graptoleberis testudinaria were the most frequent (Table 2). The Copepoda taxocoenosis consisted of 28 taxa, amounting to 74% of all Copepoda species found. Eudiaptomus gracilis, Diaptomus castor and cyclopoids Acanthocyclops robustus, A. vernalis and Cyclops vicinus were the most frequent ones among pelagic calanoids species. Eucyclops serrulatus and Macrocyclops albidus prevailed among phytophilous species. Cladocera Bosmina coregoni, Pleuroxus denticulatus, Daphnia parvula, D. ambigua, Moina weismanni and the calanoid Eurytemora velox were found from invaders. Dead meanders and meadow pool inside-dikes We found 36 Cladocera species in this arm type. There were species of genera Diaphanosoma, Daphnia, Moina and Bosmina longirostris present in this environment. The meadow pool Pod Devínom (Loc. 15) forms the exception. It recorded a significant prevalence of littoral species Daphnia curvirostris, Megafenestra aurita, Simocephalus vetulus and S. congener (Table 2). The Copepoda taxocoenosis included 20 species. Invaders Daphnia ambigua and Eurytemora velox were found. Old meanders and oxbow outside-dikes In this arm type we found 36 Cladocera and 22 Copepoda. Littoral species prevailed (81%) in the Crustacea taxocoenosis. The typical species were Daphnia curvirostris, Mixodiaptomus kupelwieseri and Megacyclops viridis. Other common species were Daphnia pulex, D. pulicaria, Oxy- urella tenuicaudis, Canthocamptus staphylinus, Paracyclops poppei and Attheyella (B.) trispinosa. From invader species only E. velox was found in the arm Bezodné (Loc. 10).

207 Tab. 2. Species composition and presence (+) of cladocerans (Crustacea, Cladocera) of water bodies of the Morava river floodplain in 1994–1995 and 2001 locality number 1 2 3 4 56789101112131415 taxon Ctenopoda Sididae Sida crystallina (O. F. Müller, 1776) + + + + + + + + + Diaphanosoma brachyurum (Liévin, 1848) + + + + + + Diaphanosoma mongolianum Ueno, 1938 + Diaphanosoma orghidani Negrea, 1982 + + + + + Anomopoda Bosminidae Bosmina coregoni Baird, 1875 + + Bosmina longirostris (O. F. Müller, 1776) + + + + ++++++ + ++ Chydoridae Eurycercus lamellatus (O. F. Müller, 1776) + + + + Pseudochydorus globosus (Baird, 1843) + + + + Chydorus sphaericus (O. F. Müller, 1776) + + + + +++++++++ + Graptoleberis testudinaria (Fischer, 1848) + + + + + + + + + + Pleuroxus truncatus (O. F. Müller, 1776) + + + + + + + + Pleuroxus laevis Sars, 1862 + + Pleuroxus trigonellus (O. F. Müller, 1776) + Pleuroxus aduncus (Jurine, 1820) + + + + ++++++++++ Pleuroxus denticulatus Birge, 1879 + Leydigia leydigii (Schoedler, 1862) + + + + Dunhevedia crassa King, 1853 + + Alonella nana (Baird, 1843) Alonella excisa (Fischer, 1854) + + + + + + + + Alonella exigua (Lilljeborg, 1853) + + Alona guttata G. O. Sars, 1862 + + + + + + + + + Alona costata G. O. Sars, 1862 + Alona rectangula G. O. Sars, 1862 + + + + + + + + + Alona quadrangularis (O. F. Müller, 1776) + + Alona affinis (Leydig, 1860) + + + + Oxyurella tenuicaudis (Sars, 1862) + Tretocephala ambigua (Lilljeborg, 1900) + + + Acroperus harpae (Baird, 1836) + + + + Acroperus neglectus (Lilljeborg, 1900) + + + + + + Daphnidae Ceriodaphnia reticulata (Jurine, 1820) + + + + + + + + + Ceriodaphnia pulchella G. O. Sars, 1862 + + + + ++++++ + Ceriodaphnia megops G. O. Sars, 1862 + + + + + Ceriodaphnia laticaudata P. E. Müller, 1867 + + Ceriodaphnia rotunda Sars, 1862 + + + Ceriodaphnia quandrangula (O. F. Müller, 1785) + + + + + + Simocephalus serrulatus (Koch, 1841) + Simocephalus vetulus (O. F. Muller, 1776) + + + + +++++++++++ Simocephalus exspinosus (Koch, 1841) + + + + + + + + Simocephalus congener Schoedler, 1858 + + + + + Daphnia pulex Leydig, 1860 + Daphnia pulicaria Forbes, 1893 + + Daphnia curvirostris Eylmann, 1887 + + + + Daphnia parvula Fordyce, 1901 + + + + Daphnia ambigua Scourfield, 1946 + + + + + + Daphnia longispina O. F. Müller, 1785 + + + + + + + + + + +

208 Tab. 2. continuation locality number 123456789101112131415 taxon Daphnia galeata G. O. Sars, 1863 + ++++++++ Daphnia cucullata G. O. Sars, 1862 + + + + + Megafenestra aurita (Fischer, 1849) + + + + + Scapholeberis rammneri Dumont et Pensaert, 1983 + + + + Scapholeberis mucronata (O. F. Müller, 1776) + +++++++++++ + Moinidae Moina micrura Kurz, 1874 + +++++ ++ Moina weismanni Ishikawa, 1896 + +++++ ++ + + Macrothricidae Ilyocryptus sordidus (Liévin, 1848) + + Ilyocryptus agilis Kurz, 1878 + + + + Macrothrix laticornis (Jurine, 1820) + + Haplopoda Leptodora kindtii (Focke, 1844) + +

DISCUSSION A relatively high number of Cladocera (58 taxa) and Copepoda (38 taxa) found in the area between the 66th and 0,5th river kilometre confirms that the Morava floodplain is a relatively undisturbed biotope (see Hudec 1999). The occurrence of genus Daphnia at our localities corresponds to their natural habitats and the present status of their distribution (Hrbáček 1987). The Cladocera taxocoenosis represents 60% of the 96 cladocerans species (Hudec 1998) occurring on the Slovak territory. The number of planktonic crustaceans species found in the alluvium of Morava (96 taxa) appears to be high also in comparison with findings of other authors who examined biotopes of other inundation areas. This number is a little higher than 80 taxa of Terek & Obrdlík (1992), found in several habitats of the Rhine River. It is also higher than 50 planktonic crustacean species of Gulyás (1994), found in waters of the Sigetköz arms of the Danube inundation in Hungary. Vranovský (1997) determined 30 Copepoda taxa from five Danube arms and two main stream profiles on the Slovak territory. The harpacticoid Nitocra hibernica (Brady, 1880) was one of the most dominant species. It was not recorded from the Morava alluvium. However, 80% of copepods that Vranovský (1997) had found in Danube arms were found also in Morava arms. During the extensive recent faunistic research of ten Danubian side arms, 72 Cladocera and 25 Copepoda taxa were found between Dobrohošť and Číčov villages (river km 1841–1081) (Illyová 1996). Danubian arm species, which were not found in the Morava floodplain, are the rare cladoceran Anchistropus emarginatus Sars, 1862 and the benthic cladocerans Disparalona rostrata (Koch, 1840), Macrothrix hirsuticornis (Norman et Brady, 1867) and Pleuroxus uncinatus (Baird, 1850). Adámek & Sukop (1992) found approximately the same number of Cladocera (53 taxa) and Copepoda (41 taxa) in Morava waters to the north of our study area. Part of the Morava floodplain, namely the confluence of Morava and Dyje rivers, was studied in the project on aquatic invertebrates in the biosphere reserve Pálava in Czech Republic (Opravilová et al. 1999). Sukop & Kopecký (1999) found 29 Cladocera species in this area. We found all of them in our study area, except of Daphnia magna Straus, 1820. Only Eudiaptomus vulgaris (Schmeil, 1898) from 17 copepod taxa determined by Kopecký et al. (1999) was not present in our study area.

209 Tab. 3. Species composition and presence (+) of copepods (Crustacea, Copepoda) of selected habitats of Morava river floodplain in 1994–1995 and 2001 locality number 1 2 3 4 56789101112131415 taxon Calanoida Temoridae Eurytemora velox (Lilljeborg, 1853) + + + Diaptomidae Arctodiaptomus bacillifer (Brady, 1880) + + Diaptomus castor (Jurine, 1820) + + + + + Eudiaptomus gracilis (Sars, 1863) + + + + + + + + + + + Eudiaptomus zachariasi (Poppe, 1886) + + + + Mixodiaptomus kupelwieseri (Brehm, 1907) + + + + Cyclopoida Cyclopidae Eucyclopinae Macrocyclops fuscus (Jurine, 1820) + + Macrocyclops distinctus (Richard, 1887) + Macrocyclops albidus (Jurine, 1820) + + + + + + + + + + + Eucyclops macrurus (Sars, 1863) + Eucyclops speratus (Lilljeborg, 1901) + + + + + Eucyclops serrulatus (Fischer, 1851) + + + + +++++++ + E. serrulatus var. proximus (Lilljeborg, 1901) + Tropocyclops prasinus (Fischer, 1860) + Mesocyclops leuckarti (Claus, 1857) + + + + + + + + + Paracyclops fimbriatus (Fischer, 1853) + + Paracyclops poppei (Rehberg, 1880) + Cyclopinae Metacyclops gracilis (Lilljeborg, 1853) + + Cryptocyclops bicolor (Sars, 1863) + + + + + Microcyclops varicans (Sars, 1863) + + + Megacyclops viridis (Jurine, 1820) + +++++++ Megacyclops gigas (Claus, 1857) + + Megacyclops latipes (Lowndes, 1927) + + Acanthocyclops robustus (Sars, 1863) + + + + ++++++ + + Acanthocyclops vernalis (Fischer, 1853) + + + + + Diacyclops bicuspidatus (Claus, 1857) + + + + + + + Diacyclops bisetosus (Rehmberg, 1880) + + + + Cyclops furcifer Claus, 1857 + + + + Cyclops insignis Fischer, 1857 + Cyclops strenuus Fischer, 1851 + + + + + + + + + Cyclops vicinus Uljanin, 1875 + + + + +++++ + Thermocyclops crassus (Fischer, 1853) + + + + + + + ++++ + Thermocyclops dybowskii (Lande, 1890) + Thermocyclops oithonoides (Sars, 1863) + + + +++++++ Ectocyclops phaleratus (Koch, 1838) + + Harpacticoida Attheyella (B.) trispinosa (Brady, 1880) + Bryocamptus (B.) minutus (Claus, 1863) + + + + Canthocamptus staphylinus (Jurine, 1820) + + + + + + + + + + + + We assume that invaders drifted into the Morava inundation either from the South Moravia lenitic biotopes (D. parvula, D. ambigua, M. weismanni and B. coregoni) or expanded from the Danube inundation area (P. denticulatus and E. velox); both alternatives are possible. For example, the species Bosmina coregoni probably drifted from the Nové Mlýny dam where is was

210 determined by Adámek & Sukop (1992). However, the species could migrate also from the Danube River where Vranovský (1974) and Hudec (1989) found it in the main stream and Číčov Arm, respectively. The direction in which the species Daphnia parvula migrated into the Morava alluvium remains questionable. The species was frequent in Morava side arms in 1994–1995 and occurred also in the Křivé jezero lake plankton (Sukop & Kopecký 1999) in the South Moravia region. Other authors do not mention Daphnia parvula in the Morava alluvium. It has not been found in the Danube inundation either. Hudec (1998) assumes that Daphnia parvula migrates to Slovakia from the Morava and Dan- ube river basins similarly as B. coregoni and D. ambigua. Invader cladocerans could get to this region from the water systems of the South Moravia. This could relate to the fact that water birds, potential carriers, migrate in larger numbers than before after the construction of the Nové Mlýny Dam. The species Eurytemora velox penetrated into the Morava inundation most probably from the Danube where it was the dominant species in mid nineties at several localities (Vranovský 1997). The species Pleuroxus denticulatus spread in the Danube inundation with the same veloc- ity. It was recorded for the first time in 1992 (Terek 1997) but it occurred almost in the whole Slovak Danube section in mid nineties (Hudec & Illyová 1998). Crustaceoplankton taxocoenoses in various types of arms, oxbows and temporary pools re- flected different character of these environments. Pond assemblage prevailed in water bodies with the stable water level. Small Cladocera species and small-size plankton (unpublished data) indicated high densities of planktivorous fish (Hrbáček 1962). Phytophilous crustaceans inhabited the littoral overgrown with macrovegetation. The assemblage of phytophilous and benthic species, Tretocephala ambigua, Daphnia curvirostris, Mixodiaptomus kupelwieseri, Megacyclops viridis, Paracyclops poppei, Thermocyclops dybowskii, Attheyella (B.) trispinosa, in old meanders and pools with abundant macrovegetation occurred. Kopecký & Koudelková (1997) found the similar species composition in two pools of the Morava River floodplain. The crustaceans taxocoenosis (Cyclops strenuus, Mixodiaptomus kupelwieseri and Daphnia curvirostris), found in periodic pools and temporary arms, corresponds to associations described from the Záhorie and Poduna- jská lowlands (Štěrba 1988), with exception of missing D. magna. Protection of the original aquatic ecosystems undisturbed by anthropogenic impact is the inevitable condition of preservation of aquatic fauna biodiversity in the Morava inundation. The uniqueness of this area is supported by the presence of rare species such as Hemidiaptomus hungaricus Kiefer, 1933 or Heterocope saliens (Lilljeborg, 1863) in the Záhorie lowland (Brtek 1953). Other crustaceans worthy of protection are Lepidurus apus Linnaeus, 1758 and Sipho- nophanes grubii (Dybowski, 1860) occurring in snow and flood pools (Lukáš 2000).

A c k n o w l e d g e m e n t s The research was supported by the grant No. 1/8200/01 from the Slovak Grant Agency for Science VEGA. Authors thank to Igor Hudec for the provision of his determined Cladocera material from project of Otakar Štěrba during 1994–95, and to Otakar Štěrba for his kind permission to use data from the unpublished report. We are grateful to reviewers for their constructive criticism of an earlier version of this paper. We also thank Michal Nemčok for his linguistic help with the English manuscript.

REFERENCES

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212 Acta Soc. Zool. Bohem. 66: 213–220, 2002 ISSN 1211-376X

Moina (Crustacea: Anomopoda, Moinidae) in the Czech Republic: a review

Adam PETRUSEK

Department of Hydrobiology, Charles University, Viničná 7, CZ–128 44 Prague 2, Czech Republic; e-mail: [email protected]

Received April 10, 2002; accepted September 3, 2002 Published November 4, 2002

Abstract. Current state of knowledge about general characteristics and ecology of the Central European species of Moina Baird, 1850 is summarised. Five species present in the Czech Republic or in the immediate vicinity can be divided into two groups according to their ecology: Two of them – Moina macrocopa (Straus, 1819) and M. brachiata (Jurine, 1820) – have larger body size and they are common in small ephemeral localities or highly eutrophic village ponds in the lowlands of the whole country, whereas M. micrura Kurz, 1874 and M. weismanni Ishikawa, 1896 are generally smaller and live in larger permanent waters. M. micrura is a native species, described from a locality in Central Bohemia. M. weismanni is likely a Far East invader but it has been present in the region for several decades already, at least since early 1930’s. The last species, M. ephemeralis Hudec, 1997, was described from a fishpond in Slovakia only very recently; however, it had been probably overlooked in the past due to the similarity of parthenogenetic females as well as usage of misleading identification keys. Ecology, review, Cladocera, Moina, Czech Republic, Palaearctic region

Moina Baird, 1850 (Crustacea: Anomopoda: Moinidae) is a cladoceran genus closely related to Daphniidae (Goulden 1968, Fryer 1995). They are opportunistic cladocerans typically occurring in temporary pools, saline lakes or other waters with extreme conditions (e. g., with high temperature fluctuations). The genus has a worldwide distribution (except Antarctica). The majority of the species can be found in areas with a relatively warm climate, from tropical to temperate zones. There are only very few exceptional reports of moinids from subarctic or alpine regions (Šrámek- Hušek 1962, Flössner 2000). All Moina are small or medium-sized cladocerans. The body length of adult parthenogenetic females varies between 0.5 and 1.8 mm, depending on the species. Males are always smaller than females. The appearance, functional morphology and presumed phylogeny of Moina are described in details in the monograph by Goulden (1968). In this complete revision of the genus, the author pointed out some specific morphological characteristics (e. g., morphology of trunk limbs, head shape, antennules) and peculiarities in sexual cycle and development of Moina. In his opinion, these specific characters were important enough to separate two genera, Moina and Moino- daphnia Herrick, 1887, from the rest of Daphniidae. He assigned these genera to the newly described family Moinidae. This separation of the family has been recently subject to criticism as a result of both morphological analyses (e. g., Fryer 1995) and DNA studies (Schwenk et al. 1998). However, additional sequence data from three Moina species suggest that this genus is divergent from other daphnid genera and may constitute a well-defined group (Petrusek, unpublished data). Several species of Moina have considerable economic importance. Most of the species have a short generation time, fast population growth and they are easy to keep in culture. There is an

This contribution is dedicated to Doc. RNDr. Jaroslav Hrbáček DrSc., upon the occasion of the 80th anniversary of his birthday (12th May 1921).

213 increasing interest in production of Moina as a cheap and nutritionally valuable fish food for aquaculture (e. g., Alam et al. 1993, Tamaru et al. 1997). Moina is also routinely used as a test animal in toxicological assays (e. g., Krishnan & Chockalingam 1989, Wong 1989). In addition to well- known Daphnia Müller, 1785, Moina has been used as a convenient model organism for studies of cladoceran physiology, ontogenesis, genetics etc. The findings about its biology formed substantial parts of some influential “classical” papers (e. g., Weismann 1877, Banta 1939). Special features of the sexual cycle of Moina Moina reproduces by the cyclic parthenogenesis as most of cladocerans do. The typical reproductive cycle of daphniid cladoceran (and its impact on the genetic structure of populations) is described and discussed in many reviews (e.g., Mort 1991, De Meester 1996). Although Moina reproduction follows the same general pattern as Daphnia, there are some differences arising from peculiarities in its ontogeny. The parthenogenetic females of Moina possess a special placenta-like structure (“Nährboden” sensu Weismann 1877; “marsupial organ” sensu Smirnov 1976) that presumably serves to nourish the developing embryos in the brood pouch (Weismann 1877, Rammner 1933, Goulden 1968). Organs with a similar function have independently developed also in other cladoceran taxa – in all families of Onychopoda and in Penilia avirostris Dana, 1849 (Ctenopoda: Sididae) (Makrushin 1985). The yolk content of parthenogenetic eggs is reduced in the taxa possessing placenta (Rammner 1933, Makrushin 1985) and the eggs are not able to develop out of the brood pouch of the mother. This adaptation could possibly lead to increased brood sizes and/or faster egg production. No further details on function and physiology of the placenta of moinids are available. The presence of the placenta apparently prevents the parthenogenetic females of Moina from forming of an ephippium. This slightly changes the sexual phase of the reproductive cycle of Moina. Although any parthenogenetic female can switch to sexual reproduction in Daphnia or other Anomopoda, it is not the case of Moina. Males can develop in a brood of any parthenogenetic female of Moina but the sexual eggs and ephippia can only be produced by freshly matured females (Goulden 1968). The sexual females of Moina can continue to produce sexual eggs and ephippia throughout their life. The new ephippium is formed immediately after the deposition of the previous one and the females are ready for the next mating. This allows one female to produce several genetically diverse resting eggs during the sexual phase of reproduction, even in species where only one sexual egg is deposited into the ephippium. However, once a sexual female switches to parthenogenetic reproduction, this switch is irreversible. One moult is necessary between the deposition of the ephippium and the first parthenogenetic brood in at least several Moina species (Goulden 1968; pers. obs.). Goulden suggested that this post-sexual instar was necessary for placenta formation. Moina in Europe and in the Czech Republic Eight species of Moina have been recorded from the European continent. Moina lipini Smirnov, 1976 was described from a fishpond area near Moscow (Russia) and there are no reports of this species from Central or Western Europe. Moina salina Daday, 1888 has been described from Transylvania and occurs in saline waters of the Old World. (The name M. mongolica Daday, 1901 is still widely in use, however, it is only a junior synonym of the same species (Negrea 1984).) In Europe it is present in Eastern European lowlands and in the Mediterranean region – e.g., on the Balkan Peninsula (Stephanides 1948, Negrea 1984), in Spain (Alonso 1996), and on Sardinia (Margaritora 1971). This species does not

214 occur in the Czech Republic, the nearest localities with its presence are in southern Hungary (Forró 1988, Hrbáček et al. 1978). Moina affinis Birge, 1893 is a North American invader. It has been repeatedly recorded in Italian rice fields in the last 40 years. First findings were published by Moroni (1962); for more recent data see Margaritora et al. (1987) or Leoni et al. (1999). The remaining five species of European Moina can be found on the territory of the Czech Republic and Slovakia. These are Moina macrocopa, M. brachiata, M. micrura, M. weismanni, and M. ephemeralis. The differential diagnosis of these species has been given in papers of Hudec (1988, 1989, 1997). Our species of Moina can be divided into two groups according to their preferred habitat and corresponding ecological traits. The facts about their ecology and habitat preference given below describe the situation in Central Europe. Moina brachiata and Moina macrocopa – species of puddles and hypertrophic pools Two species, Moina brachiata and M. macrocopa belong to a group of “large” Moina species – their parthenogenetic females can grow up to 1.5 mm and their mean size is usually over 1 mm (Goulden 1968). They are characteristic inhabitants of small, usually ephemeral water bodies in the temperate zone. Both species prefer lower altitudes, they are rarely found higher than 450 m a.s.l. in Central Europe (Hudec 1989, pers. obs.). They sometimes co-occur in the same water bodies (Petrusek 2000). Moina brachiata (Jurine, 1820) is the type species of the genus. It is an Old World species, widely distributed in Europe, Africa and Central Asia (for details on distribution of all species, see Goulden 1968, Smirnov 1976, Hrbáček et al. 1978, Flössner 2000). Moina macrocopa (Straus, 1819)* is widespread mostly in Europe, North Africa (Algeria), Mid- dle East, Eastern Asia and North America. The populations from Paleotropic and Palearctic regions do not differ substantially in their morphology. They belong to the typical form, designated by in Goulden (1968) as the subspecies M. m. macrocopa (Straus 1819). There is only one isolated report of M. m. macrocopa from the Neotropic region (Paggi 1997) and that could have been a case of the recent species introduction. In North America, M. macrocopa occurs in the United States (Goulden 1968) and Mexico (F. Martinéz-Jerónimo, pers. comm). However, animals from these populations differ from the typical form by the pattern of ephippial surface and setation of the carapace rim. They were described as the new subspecies M. m. americana Goulden, 1968. The actual extent of the divergence between the two subspecies is not known yet. There are two basic types of habitats strongly preferred by M. brachiata and M. macrocopa. Small village ponds or sewage ponds are examples of the first type. These are usually permanent water bodies, highly eutrophic and with excess of food supply. However, the conditions during the season become unfavourable for most of the zooplankton species. The water temperatures can be relatively high in summer and there are often periods of low oxygen content (especially if the water surface is covered with floating plants such as Lemna, or detritus). Although fish may be present, their predation pressure is not very important factor structuring zooplankton communities in those ponds. Moina usually co-occurs with some large Daphnia species (D. magna Straus, 1820, D. pulex Leydig, 1860) in such habitats (Šrámek-Hušek 1941).

* Alonso (1996) suggested that the name Moina macrocopus should be used instead because of linguistic and historical reasons. Although this suggestion follows the ICZN rules, I still use the name M. macrocopa. The taxon is widespread and the name macrocopa has been in use continuously for more than ninety years. I believe it should be assigned the status of nomen conservandum to avoid confusion.

215 Ephemeral pools (such as rainpools or ditches; further on called “puddles”) are examples of the second habitat characteristic for Moina brachiata or M. macrocopa. Typical puddle is a small water body, with a diameter of one to several meters and maximum depth often not exceeding 20 cm, often drying up several times during the summer season. The volume and duration of water is dependent mostly on the rain frequency and exposition to the sunlight and wind. It is usually either dry or completely frozen during the winter. Puddle localities are unstable, they can deterio- rate and/or disappear completely during few seasons; so the Moina population does not find suitable conditions at the site anymore. Ephemeral habitats inhabited by M. macrocopa and M. brachiata are usually found in open, unshaded areas (pers. obs.), and therefore they are often considerably warmed up during the day. The temperature differences between day and night in puddles can rise up to 15° C (Maier et al. 1998). Water level fluctuations in puddles induce abrupt changes of both biotic and abiotic conditions – salinity, seston (and food) concentration etc. (Hronešová 1992). Changes of water volume also directly affect the density of populations. Puddles often harbour a high diversity of invertebrates, including other cladocerans (e.g., Daphnia obtusa Kurz, 1875), ostracods, copepods and insects (pers. obs.). The most important predators possibly affecting Moina populations in this type of habitat probably belong to the latter two groups. Other crustaceans typical for ephemeral habitats, Anostraca, Notostraca, and Conchostraca, may also co-occur with Moina (Maier et al. 1998, pers. obs.). Puddle species of Moina can tolerate high water temperatures (Maier 1993) and elevated content of dissolved substances. This tolerance allows them to colonise water bodies where the extreme environmental conditions limit the presence of their potential zooplankton competitors (e.g., cattle manure runoff with high organic content). M. brachiata is also one of few cladoceran inhabitants of sodic waters in Austria, Hungary and Serbia, occurring both in temporary pools and permanent “lakes” (Metz & Forró 1989). Similar saline habitats are uncommon in the Czech Repub- lic. One such locality (with an abundant presence of M. brachiata) is a swamp adjacent to the fishpond Nesyt near Lednice in South Moravia (pers. obs.). Both M. brachiata and M. macrocopa can reach densities over 10,000 ind×l–1 (Maier 1993, Khalaf & Shihab 1979) in favourable conditions. The highest abundance usually corresponds with periods of low water level in temporary pools, when population growth and drying out of the habitat have synergistic effect. Such crowding lowers dramatically the available food supply, consequently the decrease of ingestion stops population growth and encourages sexual reproduction (D’Abramo 1980), preparing the Moina population for possible drying of the habitat. Each of the two puddle species can be found occasionally in fishponds. This occurs in periods when conditions in the pond approach those experienced in the temporary waters – for example within few weeks after the flooding of the area. The population of Moina can reach a brief peak of abundance in such cases. However, neither M. brachiata nor M. macrocopa regularly occur in permanent water bodies with the presence of fish or large Daphnia species. Moina micrura, M. weismanni and M. ephemeralis – species of ponds These three species are representatives of smaller cladocerans of the “shallow lake” habitat and they share together many characteristics. Localities where these Moina species occur include fishponds, dead river arms and oxbow lakes, flooded sandpits and similar water bodies (Hudec 1988, 1997, I. Přikryl – unpublished data), especially in warmer areas. Planktivorous fish commonly prevail in such waters and shift the composition of crustacean zooplankton towards small cladocerans. Adult females of all three Moina species from permanent water bodies have relatively small body size, usually not exceeding 1 mm. M. ephemeralis is larger than the other two species – the

216 largest specimens measured up to 1.36 mm (Hudec 1997). Their populations are intermittent and no adults survive over winter. Populations of Moina often appear in short-time peaks of abundance only, usually in spring or autumn (Hudec 1997, I. Přikryl – unpublished data). M. micrura can occasionally reach densities up to 8,000 indx.l–1 during these peaks (Flössner 2000). If prevailing for longer time, Moina populations have usually low densities and occur together with other genera of small pelagic cladocerans (e.g. Bosmina Baird, 1846, some Daphnia species, Diaphano- soma S. Fischer, 1850 etc.). Two or even all three species can be occasionally found together on the same locality (Hudec 1997, Petrusek 2000). Moina micrura Kurz, 1874 was until recently the only species of Moina with a small body, recognised from the Central European region. It is a typical example of the unresolved taxonomy within the genus. It was described from a pond near Malešov (near Kutná Hora, Central Bohemia). The type specimens are not available and the type locality no longer exists – the pond had been dried up and the area forested. The original description did not include enough details and probably was not widely known; so several other similar species have been described during following decades from different parts of the world. More information about morphology of M. micrura sensu stricto was added later in the report of the presence of this species in Bohemia (Šrámek- Hušek 1940). However, the detailed redescription of M. micrura from another Czech locality remained unpublished (Šrámek-Hušek, unpublished manuscript). The morphological variability of populations of small-sized Moina is so high that seven species names were declared invalid and synonymised with M. micrura in the revision of the genus by Goulden (1968); some species were included also later (Smirnov 1976, Sharma & Sharma 1990). Moina micrura is considered to be a cosmopolitan species with extensive morphological and ecological plasticity, occurring in a wide range of different habitats. M. micrura sensu lato (Goulden 1968) has been recorded in various habitats in most parts of the world, with the exception of cold regions. Partly because of acknowledged variability of the species, any population of small Moina found on the territory of former Czechoslovakia had been previously identified as M. micrura or invalid M. rectirostris (Leydig, 1860). The results of the experimental hybridisation of clones of M. micrura sensu lato of different origin and the sequence comparison of the mitochondrial gene for 12S rRNA show that M. micrura is clearly a complex of sibling species (Petrusek 2000). How- ever, the Central European populations belong undoubtedly to Moina micrura sensu stricto. Two more species with similar morphology and ecology, M. weismanni and M. ephemeralis, occur in Central Europe. The most important species-specific characters can be found on the sexual individuals. The morphology of ephippial females allows an easy identification of the species. Small differences in morphology of parthenogenetic females can explain the fact that M. weismanni (and probably also M. ephemeralis) often escaped the detection. When a sample of the population does not contain sexual animals, the correct species assignment can be a difficult task. M. weismanni and M. ephemeralis are absent from most of the identification keys of Europe- an cladocerans (including recent publications – e.g., Flössner 2000). The use of older publications (e.g., Šrámek-Hušek 1954, Šrámek-Hušek et al. 1962) that include invalid species names (M. rectirostris) and incorrect descriptions of valid species (M. brachiata) still adds to the taxonomical confusion. Moina weismanni Ishikawa, 1896 is thought to be a Far East invader, brought to Europe with the cultivation of rice (Margaritora et al. 1987, Hudec 1990). It is widespread in South-East Asia – Japan, China, Indonesia, and Indian subcontinent (Smirnov 1976). Since the differential diagnosis of the species (e.g., in Hudec 1990) had become widely known, it has been recorded in various localities in both the Czech Republic and Slovakia (Hudec 1988, I. Přikryl – unpublished data).

217 However, Moina weismanni has been apparently a part of the Central European fauna for much longer than previously thought. The occurrence of this species in Bohemia is documented back to 1931. There is a well-preserved sample of a rich M. weismanni population, including males and ephippial females, collected by Šrámek-Hušek in a village pond in Bohumileč (Pardubice district) on August 14, 1931. The animals were identified as M. rectirostris (invalid name, which had been used for several different Moina species) (Šrámek-Hušek 1941), therefore the presence of this species in the old sample remained unnoticed until recently (V. Kořínek, unpublished results). Vojtek (1958) recorded the presence of M. weismanni in Southern Moravia (four localities near Znojmo) in the years 1947–1948. Although he called the animal M. micrura, he described well the morphology of sexual females. The identity of the species is beyond question thanks to his precise drawing of the ephippial surface. The presence of this species has been also recorded in several areas of Central Asia and Russia (Mirabdullaev 1992), on the Balkan peninsula (Petkovski 1991), in Hungary (Hudec 1990, Forró 1999), and in Belgium (Forró et al., in prep.). It seems that its current distribution is much wider than previously thought. Either M. weismanni is quite an efficient invader, or its presence had been overlooked for a long time. The detailed comparison of European and Far East populations of M. weismanni, including molecular traits, would be helpful to validate the identity of this species and the relationship among its populations. Moina ephemeralis Hudec, 1997 is the rarest species of Moina living on the territory of the Czech Republic and Slovakia. It was described recently from Southern Slovakia (carp ponds near Hrhov) (Hudec 1997). Since then it has been found on several occasions in the floodplain of the lower reach of the river Morava (I. Hudec, pers. comm.). The distribution of this species is unknown; there are yet no records of this species from any other part of Europe. Although Moina ephemeralis is one of only three European Moina species with ephippium with two eggs (the other two are M. macrocopa and M. lipini), there are several reasons why it has probably escaped attention for a long time. First, the life cycle of M. ephemeralis is very short compared to other planktonic cladocerans (Hudec 1997), second, the correct identification of populations without sexual individuals is rather difficult, as parthenogenetic females can be con- founded with those of M. weismanni. And the last, the use of misleading identification keys could be also the reason. Four species of Moina are included in the monograph on Czechoslovak cladocerans (Šrámek- Hušek 1962). M. weismanni and M. ephemeralis are missing, but one more species, M. rectirostris (Leydig, 1860) is listed. Goulden (1968) synonymised most of the occurrences of this taxon with M. micrura, however, M. rectirostris sensu Šrámek-Hušek is equivalent to M. brachiata. Šrámek- Hušek distinguished M. brachiata and M. rectirostris by the number of ephippial eggs. Accord- ing to his key, M. brachiata should have had ephippium with two eggs (which is incorrect) whereas M. rectirostris with one egg only; M. ephemeralis would be therefore keyed out as M. brachiata. This suggests that some records of M. brachiata sensu Šrámek-Hušek could have been actually rare occurrences of M. ephemeralis.

A c k n o w l e d g e m e n t s I would like to thank Vladimír Kořínek, Igor Hudec, and László Forró for sharing information and valuable discussions. The research of cladoceran diversity (incl. Moina) is supported by Grant Agency of the Charles University (project no. 146/2001) and Ministry of Education of the Czech Republic (project no. MSM113100004).

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220 Acta Soc. Zool. Bohem. 66: 221–230, 2002 ISSN 1211-376X

Two recent immigrants into Czech aquatic habitats: Daphnia ambigua and D. parvula (Crustacea: Cladocera)

Magdaléna ŽOFKOVÁ, Vladimír KOŘÍNEK & Martin ČERNÝ

Department of Hydrobiology, Faculty of Science, Charles University, Viničná 7, CZ–128 44 Praha 2, Czech Republic

Received May 8, 2002; accepted September 3, 2002 Published November 4, 2002

Abstract. Available data on the distribution of Daphnia ambigua Scourfield, 1947 and D. parvula Fordyce, 1901 in Czechia were summarized. We compare interspecific differences in the size distributions among these two invasive and a common native species D. galeata G. O. Sars, 1863 as well as locality-specific (6 Czech and 1 North American) body-size differences for each of the exotic species. Both invaders are able to attain maximal body size about 1.3 mm, a substantial overlap with the native D. galeata. In one reservoir, D. galeata population dropped the mean body size down to similar values as are common in D. ambigua. Size differences among localities are not significant due to the wide local range of values. Size distribution frequencies in a locality are mostly symmetric suggesting that input of young stages into the population in the sampling dates studied was already diminishing. The populations of invader species differ in the timing of sexual reproduction; gamogenetic populations of D. parvula occur from September to November, while those of D. ambigua were found only in May. Biological invasions, zooplankton, Daphnia ambigua, Daphnia parvula, Daphnia galeata, size distribution, gamogenetic populations, Czech Republic, Palaearctic region

INTRODUCTION Two species of the genus Daphnia Müller, 1785 widely distributed in North America, has been recently reported spreading across Europe invading various kinds of water bodies: Daphnia ambigua, originally described from a Kew Garden reservoir in London, and D. parvula, from a fish pond about 5 km south of Arapahoe, Nebraska. Starting from 1970, the former species was occasionally reported from water bodies in continental Europe: Amoros (1972) mentioned a short occurrence of D. ambigua in one fishpond in S.-E. of France, unfortunately without any further details or drawings. Well-documented records from Belgium were published by Dumont (1974), followed by Flössner & Kraus (1976), and Margaritora (1985). Daphnia parvula seems to be less frequently recorded. The species appears in recent review of Spanish cladoceran fauna (Alonso 1996), and one of the figures of postabdominal claw of D. ambigua in Margaritora (1985) may belong to D. parvula. Schrimpf & Steinberg (1982) reported the species from waters in neighbourhood of Mannheim, Germany, and Petkowski (1990) found D. parvula in Macedonia. Hudec (1990, 1991) published data on the distribution of both the species in Slovakia. Weiler (poster communication, symposium in Plön, Germany, 1999) found both species in lakes in neighbourhood of Bonn (Germany). D. ambigua was found recently in a system of interconnected ponds in Belgium (Michels et al. 2001.) German localities of both the species are summarised in Flössner (2000). In

This contribution is dedicated to Doc. RNDr. Jaroslav Hrbáček DrSc., upon the occasion of the 80th anniversary of his birthday (12th May 1921)

221 Czechia, the second author found D. parvula in late seventies (1977) in a drinking water reservoir, and D. ambigua has been regurarly recorded only from 1994 (I. Přikryl, samples and personal communication 1998). The centre of geographic distribution of both the species is on American continent (Brooks 1957), and European localities are supposed to be secondary as result of recent invasion of both the species. Careful re-examination of samples from various waters in Czechia revealed relatively frequent occurrence of both the species in habitats like reservoirs, fishponds and pools. Such situation is interesting from the ecological point of view. Newly arrived species has to found a vacant niche and be successful in inter-specific competition with native species with similar environmental requirements. The aim of the present study is to give an overview of populations living in our region. The data will be used for the further study of their phylogeography and competitive abilities.

MATERIAL AND METHODS

Beside re-examination of some of the preserved material offered by our colleagues, we have sampled prospective habitats as well as those from which one of the species has been already reported. North American material was obtained due to the kind assistance of colleagues from Canada, USA, Mexico and Cuba. Most of the material was collected with the 100-µm-mesh size plankton net and preserved with 4% formalin solution. The following table lists all the populations, which were at our disposal for the study. We omitted habitats where the species occurred only sporadically and in low numbers.

Daphnia ambigua Scourfield, 1947

MATERIAL EXAMINED. Závist Pond, Skaličany, Blatná, Sep. 22. 1999; Padrť Pond, Drásov, Příbram, Sep., 23. 1999; Novokestřanský Pond, Strakonice, Sep. 22. 1999; Nový Pond, W. of Čekanice, Blatná, Sep. 22. 1999; (all M. Žofková legit). Zlivský Pond, Hluboká, České Budějovice, June 12. 1996; Zámecký Pond, Lednice, May 22. Aug. 22. 1996; Řežabinec, Písek, Aug. 17. 1998; Domin Pond, Vrbno at České Budějovice, June 12. 1996; Věžický Pond, W. of Rovensko, June 8. Aug. 14. 1995; Skalský Pond, Protivín, Aug. 13. 1996; Jordánek Pond, Hrnčíře, Sep. 10. 1996; Komorní Pond, Turnov, Sep. 22. 1998; Žabokor Pond, Mnichovo Hradiště, Sep. 1. 1994; Žehuňský Pond, Poděbrady, July 10. 1996. (all I. Přikryl legit). Sand pit “Bagr” in park, České Budějovice, Sep. 2. 1997. (J. Seďa legit), Jul. 31. Aug. 15. Sep. 2. 1997, Jul. 2. 1998, (H. Lukčíková legit.); Orlík reservoir, Zvíkov, May 12. 1999 (L. Růžička legit). Římov reservoir, České Budějovice, May 24. 2001, (J. Macháček J. legit); village pond, Divišovice at Sedlec-Prčice, Jun. 29. 2001 (V. Kořínek legit). Channel, Pohansko, Břeclav, S. Moravia, Jun. 21. 1999 (M. Omesová legit). Backwater, river Morava, Vysoká, Slovakia, May 27. 1994. (O. Štěrba legit). Comparative material from North and Central America MATERIAL EXAMINED. Grenadier Pond, Ont., Canada, June 6. 1966 (H. Harvey legit); Upper Bass lake, Ont., Canada, June 1. 1965 (F. Rigler’s collection Univ. Toronto); Kashe lake, Muskoka Co., Ont., Canada, July 31. 1978 (M.J. Dadswell legit); Johnson lake, Florida, USA, Jan. 19. 1994 (W.M. Lewis junior legit), Jan. 28. 1987 (D.G. Frey legit); Feb. 23. 1988 (G. Deevey legit); fish pond #6, Apr. 9., Apr. 28. 1968; fishpond #15, Apr. 9. 1968, Auburn, Alabama, USA, (all J. Hrbáček legit); Laguna #1, El Dique, Cuba, March 5. 1968 (N. Martinez legit); Laguna Eduardo, prov. Habana, Cuba, June 17. 1990 (J. Fott legit); Presa los Canos, Mexico, June 17. 1990 (M. Briano legit).

Daphnia parvula Fordyce, 1901

MATERIAL EXAMINED. Ruda Pond, Třeboň, May 23. 1996 (I. Přikryl legit); Sep. 28. 1999 (M. Žofková legit); Dušákovský Pond, Třeboň, May 23. 1996 (I. Přikryl legit); Sep. 28. 1999 (M. Žofková legit); Velký Tisý Pond, Třeboň, June 26. July 17. 1996; Nový Spálený Pond, Třeboň, May 23. 1996; Žehuňský Pond, Poděbrady, July 10. 1996; Přesličkový Pond, Nové Hrady, Sep. 11. 1996; Sousedský Pond, Chlum at Třeboň, Aug. 14. 1996; Kotvice Pond, Odra river, Nový Jičín, Aug. 29. 1995, N. Moravia (all I. Přikryl legit); Božkov Pond, Mnichovice, Prague, July 23. 1987, Oct. 29. 1989 (M. Pražáková legit); Dvorský Pond, Zbiroh, Sep. 19. 1994, Nov. 27. 1994, Oct. 29. 1997; fish pond in Zbiroh, Sep. 18. 1994 (all J. Vávra legit); Žabokor Pond, Mnichovo Hradiště, Sep. 23. 1998; Novokestřanský Pond, Strakonice, Aug. 20. 31. 1998; small pond near Pařezská Lhota, Jičín, Sep. 23. 1998; fishpond S. of Branná, Třeboň, Oct. 1. 1997; Buzický Pond, Blatná, Sep. 14. 1997; Nový Pond near

222 Fig. 1. Daphnia ambigua Scourfield: a – adult female, b – adult male, c – postabdominal claw of female, d – adult male – antennule.

223 Fig. 2. Daphnia parvula Fordyce: a – adult female, b – adult male, c – postabdominal claw of a female, d – immature male – antennule.

224 Čekanice, Strakonice, Aug. 30. 1998; Řežabinec Pond, Písek, Aug. 30. 1998; forest pond, Libínské sedlo, Prach- atice, July 17. 1997; Rokytnický Pond, Hrubá Skála, Sep. 23. 1998; Pýcha Pond, Skaličany, Blatná, Oct. 4. 1998; fishpond in Podkost, Sobotka, Sep. 23. 1998, (all V. Kořínek legit); Skalka Pond, Drásov, Příbram, Oct. 31. 1997 (K. Urbanová legit); Hostivař reservoir, Prague, July 8. 1980 (J. Fott legit), Aug. 14., Sep. 18., Oct. 2. 1981 (all E. Hrušková legit); Vrchlice reservoir, Kutná Hora, June 21. 1977, (V. Gottwaldová legit); backwater Dlouhá, Upper Lužnice river, N. Ves, Suchdol, Sep. 2. 1992 (J. Hrbáček legit); Římov reservoir, Oct. 8. 1997 (J. Seďa legit); Pond Biřička, Hradec Králové, Aug. 31. 1998 (M. Dewetter legit). Village pond in Sedlce, České Budějovice, Oct. 15. 2000 (L. Stará legit). Pond Jejkal Dolní, Vranov nad Dyjí, Jun. 8. 2001; pond Jejkal Horní, Jun. 8. 2001; Červený pond, W of Znojmo, Jun. 7. 2001; fish pond NW of Ješetice, Votice, Jul. 2. 2001, (all V. Kořínek legit). Pastvisko pond, Břeclav, Jun. 3. 1993; Ostřicová pool, Jul. 8. 1993; Panenská pool, Jul. 8. 1993, Křivé jezero reserve, S. Moravia (all O. Skácelová legit); backwater at Devínská Nová Ves, Slovakia, May 27. 1994 (O. Štěrba legit). Comparative material from North and Central America MATERIAL EXAMINED. Lake Max, Turtle Park, Manitoba, Canada, Aug. 7. 1969; Lake Winnipeg, Manitoba, Canada, July 9. 1969, (K. Patalas legit); Heart Lake, Ontario, Canada, May 28., Aug. 6., Nov. 5. 1965, (all F. Rigler’s collection, Univ. Toronto); Teapot Pond, Ont., Canada, May 28. 1961; Toussaint Lake, Ont. Canada, June 2. 1965, (C.H. Harvey legit); Lake #302, Erickson, Manit., Canada, Oct. 13. 1971, (V. Kořínek legit); Lynx Lake, B.C., Canada, July 15. 1969; Shell Lake, B.C., Canada, July 3. 1960, (all T. Northcote collection, Univ. B.C.); Acueducto Holguin, Cuba, Apr. 23. 1966. (M. Legner legit).

RESULTS Morphology Daphnia ambigua. Females of Central European populations are mostly without any spine on top of head or the spine is only faintly suggested in sub-cuticle tissues. We have found only two habitats where females had remarkably pronounced apical horn on top of head. Both the habitats are fishless pools with Chaoborus Lichtenstein, 1800 larvae present. Ocellus is seldom pigmented. Other characters, including those of males, were found similar to North American populations. In some of the ponds, the species co-occurs with D. parvula and the only reliable differentiation has to be based on the difference in pectens on the postabdominal claw (Fig. 1). Daphnia parvula. There was no difference in the morphology of females and males between populations from our region and those from North America (Fig. 2). Habitats Populations of D. ambigua dwell mostly in shallow fishponds or in pools and backwaters along rivers. Recently it was found in one reservoir (Římov). On the other hand D. parvula probably started to invade first such relatively young habitats as are reservoirs not more than several decades after their construction. Only in nineties we have found the species in many fishponds. Biology The peak of the population densities in D. ambigua is reached mostly in August and at the beginning of September. Nevertheless the populations start to occur already from May. Gamogenetic populations were found only in May. Occurrence of males and ephippial females seems to be rare, we have found it only in 4 habitats (a dug out flooded with water, a fish pond, one river backwater and a reservoir). Besides populations from American continent, we have checked one locality reported outside the supposed Euro-American range of the species: Japan (Ueno1960). The population from a high mountain lake Mikuriga-ike (Toyama ken, Honshu, altitude 2405 m, Sep. 25. 1978, K. Okamoto legit) belongs certainly to the “Daphnia longispina” group of species and morphology of females as well as males of that population differs substantially from that of D. ambigua populations. Maximal population density of D. parvula populations is reached mostly during the late summer: second half of August and September. Only in few cases we have found dense populations in

225 spring (May). Males and ephippial females occur in the period September–October. The co-occurrence with native species D. galeata G. O. Sars, 1863 is quite common in our samples. Both the species are small. Body size according to Brooks (1957) is 0.7–1.0 mm for D. parvula and 1.0 mm for D. ambigua. As planktivorous fish dominate most of our habitats where the species are dwelling, we supposed that the competitive advantage of invasive species is their small body size. We compared the mean, minimal and maximal sizes of species studied with those of D. galeata from a reservoir (high predation pressure of fish and Chaoborus larvae) and a fish pond (low fish predation pressure – about 500 ind. of two years old carp) (Fig. 3). The high value of the mean body size within 4 groups of populations was found in Daphnia parvula – over 0.9 mm, and the low one in Daphnia galeata from a reservoir with presumably high predation pressure of planktivorous fish (roach) – over 0.7 mm. Comparison of means and corresponding 95% conf. intervals of body size on 13 different localities and 12 different sampling dates (including populations from two randomly selected Canadian lakes) revealed large interpopulation variability (Fig. 4). With few exceptions, the size distribution within one habitat was nearly symmetric (Fig. 5). It means that in the time of sampling the input of newly born was already decreasing. The largest individuals of both the species were found on different localities in size class 1.3–1.4 mm. However, the native D. galeata is able to reach the maximal body size in some fishponds to about 2.5 mm (Kořínek, pers. obs.).

Fig. 3. Comparison of the mean body length among three species – Daphnia parvula Fordyce, D. ambigua Scourfield (respective populations treated jointly) and D. galeata G. O. Sars (two populations with different fish predation pressure: high from Drásov reservoir at Příbram, 1998; low from pond Smyslov at Blatná, 1968).

226 Fig. 4. Comparison of mean body length among particular populations of Daphnia parvula Fordyce and D. ambigua Scourfield. Populations are numbered as follows: D. parvula: 1 – Skalka, 2 – Novokestřanský, 3 – Žabakor, 4 – Pýcha, 5 – Heart lake, 6 – Ruda, 7 – Dušákovský; D. ambigua: 8 – Upper Bass lake, 9 – Skalský Aug. 1998, 10 – Skalský Sept. 1998, 11 – Novokestřanský, 12 – Nový, 13 – Padrť, 14 – Závist. More detailed labels are to find in Fig. 5.

DISCUSSION AND CONCLUSIONS – As the species composition of the zooplankton in Czech ponds and reservoirs was intensively studied for several decades (Šrámek-Hušek 1962, Hrbáček 1962, Kořínek et al. 1986, Hrbáček 1984), the probability that both the studied species had been overlooked is negligible. We suppose that Daphnia parvula occurred in the region not earlier than in 1975, and D. ambigua not before 1990. This is in good agreement with hypothesis that the species are slowly spreading from western part of Europe eastwards and southwards. – The competitive position of both the species within the local plankton community cannot be judged from the data available. According to our results, there is an overlap with the size distribution of native species D. galeata in attainable maximal body size. Factors like the size of the first reproductive instar (primipara), natality and mortality within population and attained maximal size of competitors co-occurring in one habitat are to be studied to ascertain the mechanisms allowing successful establishment of invader populations.

227 228 Fig. 5. Size (body length) distribution within particular populations, locality and sampling dates are given. Daphnia parvula Fordyce – left column, D. ambigua Scourfield – right column, overall mean measurements – top of the graph.

– Differentiation of both the species from other females of native Daphnia species is based mainly on the reduction of rostral part of head. Both species differ in the size of three pectens of spinules on postabdominal claws: in D. ambigua all three are small and of the same length, in D. parvula spinules in the middle pecten are longer than in remaining two (Kořínek 1988) . Spinules are however delicate and not so robust like in the group of D. pulex. The presence of ocellus is not a reliable character as the pigmentation is meagre in the European populations of both the species. To differentiate the males, the tip of the antennular flagellum is the best diagnostic character.

A c k n o w l e d g e m e n t The project was partly supported by the grant to the first author (project 105/1998) from Charles University and partly from Czech Ministry of Education (Res. Project 3111-4). We are indebted to all colleagues who helped with their own material.

229 REFERENCES

ALONSO M. 1996: Crustacea, Branchiopoda. Fauna Iberica 7. Madrid: Museo Nacional de Ciencias Naturales, 486 pp. AMOROS C. 1973: Évolution des populations de Cladocčres et Copépodes dans trois étangs piscicoles de la Dombes. Ann. Limnol. 9: 135–155. BROOKS J. L. 1957: The systematics of North American Daphnia. Mem. Conn. Acad. Arts Sci. 13: 1–180. DUMONT H. J. 1974: Daphnia ambigua Scourfield, 1947 (Cladocera: Daphniidae) on the European continent. Biol. Jb. Dodonaea 42: 112–116. FLÖSSNER D. 2000: Die Haplopoda und Cladocera (ohne Bosminidae) Mitteleuropas. Leiden: Backhuys Publishers, 428 pp. FLÖSSNER D. & KRAUS K. 1976: Zwei für Mitteleuropa neue Cladoceren-Arten (Daphnia ambigua Scourfield, 1946 und Daphnia parvula Fordyce, 1901) aus Süddeutschland. Crustaceana 30: 301–309. FORDYCE C. 1901: The Cladocera of Nebraska. Trans. Amer. Microscop. Soc. 22: 119–174. HRBÁČEK J. 1962: Species composition and the amount of the zooplankton in the relation to the fish stock. Trans. Czechoslov. Acad. Sci., Math.-Natur. Sci. Ser. 72(10): 1–14. HRBÁČEK J. 1984: Ecosystems of European man-made lakes. Pp.: 267–290. In: TAUB F. B. (ed.): Ecosystems of the World. 23. Lakes and Reservoirs. Amsterdam: Elsevier Sc. Publ. B.V, 350 pp. HUDEC I. 1990: Distribution and biology of species of the genus Daphnia, subgenus Daphnia (Cladocera, Daphniidae) in Slovakia. 1st part: D. obtusa, D. pulicaria, D. parvula. Biológia (Bratislava) 45: 491–499 (in Slovak, Engl. abstr.) HUDEC I. 1991: Occurrence and biology of the species of the genus Daphnia, subgenus Daphnia (Cladocera, Daphniidae) in Slovakia. 3rd part: D. galeata, D. cucullata. Biológia (Bratislava) 46: 129–138 (in Slovak, Engl. abstr.) KOŘÍNEK V., FOTT J., FUKSA J., LELLÁK J. & PRAŽÁKOVÁ M. 1987: Carp ponds of Central Europe. Pp: 29–62. In: MICHAEL R. G. (ed.): Ecosystems of the World. 29. Managed Aquatic Ecosystems. Amsterdam: Elsevier Sc. Publ. B. V., 166 pp. KOŘÍNEK V. 1988: [New information on limnetic cladoceran species in Czechoslovakia]. Pp.: 70–72. In: Proceedings of 8th National conference of Czechoslovak Limnological Society, Chlum u Třeboně Oct 3–7 (in Czech). MARGARITORA F. G. & SPECCHI M. 1985: Cladocera. Fauna d’Italia. Bologna: Edizioni Calderini, 399 pp. MICHELS E., COTTENIE K., NEYS L. & DE MEESTER L. 2001: Zooplankton on the move: first results on the quantification of dispersal of zooplankton in a set of interconnected ponds. Hydrobiologia 442: 117–126. PETKOVSKI S. 1990: Nachweise von Daphnia pulicaria Forbes, 1893 emend. Hrbáček (1959) und Daphnia parvula Fordyce, 1901 in Jugoslawien (Crustacea, Cladocera, Anomopoda). Mitt. Hamb. Zool. Mus. Inst. 87: 261–272. SCHRIMPF A. & STEINBERG C. 1982: Weitere Fundorte der für Süddeutschland neu nachgewiesenen Cladocere Daphnia parvula Fordyce 1901 (Crustacea, Phyllopoda). Arch. Hydrobiol. 183: 372–381. SCOURFIELD D. J. 1947: A short-spined Daphnia presumably belonging to the “longispina” group – D. ambigua n. sp. J. Quekett microscop. Club 4(11): 127–131. ŠRÁMEK-HUŠEK R., STRAŠKRABA M. & BRTEK J. 1962: Lupenonožci – Branchiopoda. Fauna ČSSR 16 [Phyllopods – Branchiopoda. Fauna of Czechoslovakia 16]. Praha: Nakl. Čs. Akad. Věd, 470 pp (in Czech, with Russ. and Germ. summ.). UÉNO M. 1960: The daphnid inhabiting the alpine lakes on Mt. Tateyama. Jap. J. Limnol. 21: 293–306 (in Japanese with Engl. summ.).

230 Acta Soc. Zool. Bohem. 66: 231–234, 2002 ISSN 1211-376X

Anisus septemgyratus (Mollusca: Gastropoda) in the Czech Republic, with notes to its anatomy

Luboš BERAN & Michal HORSÁK

1) Kokořínsko Protected Landscape Area Administration, Česká 149, CZ–276 01 Mělník; e-mail: kokorinsko@proactive,cz, Czech Republic 2) Department of Zoology and Ecology, Faculty of Science, Masaryk University, Kotlářská 2, CZ–611 37 Brno; e-mail: [email protected], Czech Republic

Received February 15, 2001; accepted October 16, 2001 Published November 4, 2002

Abstract. First specimens of Anisus septemgyratus (Rossmäessler, 1835) in the Czech Republic, were found at three localities in South Moravia in flood-plain of the Dyje River in 1998. Dissection of about 30 specimens showed anatomical differences from A. leucostoma (Millet, 1813) and A. spirorbis (Linnaeus, 1758). Also habitats of this species seem to be different from those of A. leucostoma and A. spirobis. Distribution, anatomy, Mollusca, Gastropoda, Anisus septemgyratus, Moravia, Palaearctic region

INTRODUCTION Anisus septemgyratus (Rossmäessler, 1835) is known especially from East Europe (Ložek 1986, Zhadin 1952) and its occurrence is documented also from West Siberia (Zhadin 1952). Some authors (Hudec 1967,Glöer & Meier-Brook 1998) classified this taxon only as subspecies of A. leucostoma (Millet, 1813) and other authors (Falkner 1989, Ložek 1986, Piechocki 1979) as species. According to Ložek (1986) this taxon inhabits different habitats than A. leucostoma. A. septemgyratus is known predominantly from large and not temporary pools, but A. leucostoma and A. spirorbis (Linnaeus, 1758) are typical species of small temporary pools and wetlands. A distribution of A. leucostoma is also wider (throughout the Palaearctic region) than A. septemgyratus (East Europe, West Siberia) (Ložek 1986). The nearest locality is known from Slovakia (old arm of the Hron River in Bánská Bystrica) (Ložek 1986). This species is considered as endangered or rare in most of European countries.

MATERIAL AND METHODS

Molluscs were collected from vegetation or from water level by means of a sifter. Specimens for dissection were drowned in water and later fixed in 70% ethanol. Dissected reproductive organs and shells are deposited in collections of both authors. Sample of shells from second locality is deposited also in National Museum in Prague and sample of fixed specimens is deposit in the collection of C. Meier-Brook (Germany) for further analysis.

RESULTS First specimens were found in a pool near Nejdek (data are as follows, geographical coordinates, code of the mapping square for faunistic mapping according to Buchar (1982), elevation above sea-level (approximately), description of the locality, date of investigation, name of investigator – LB – Luboš Beran, MH – Michal Horsák, LB+MH – both authors; 48° 49’ 16,96” N, 16° 46’ 52,04” E, 7166, 174 m, Nejdek, a pool /Bažina u Azantu/ on Nejdecké louky meadows between Nejdek and the

231 Fig. 1. Known distribution of Anisus septemgyratus (Rossmässler) in the Czech Republic.

Fig. 2. A shell of Anisus septemgyratus (Rossmässler) from locality Břeclav (restored pool in the Kančí obora floodplain forest, about 600 m N from the Dyje river is divided into two streams; lgt. M. Horsák, 25. IX. 1999, height 0.9 mm, width 7.1 mm). Orig. M. Horsák.

232 Dyje River, 10. IX. 1998, LB+MH). Further specimens were found at two localities near Břeclav (48° 46’ 46,75” N, 16° 52’ 37,58” E, 7267, 158 m, Břeclav, restored pool in the Kančí obora flood-plain forest, about 600 m N from the point where the Dyje River is divided to two river streams, 10. IX. 1998, LB+MH, 25. IX. 1999, MH; 48° 46’ 34,82” N, 16° 52’ 37,76” E, 7267, 158 m, Břeclav, restored pool in the Kančí obora flood-plain forest, about 300 m N from the point where the Dyje River is divided to two river streams, 11. IX. 1998, LB+MH). First locality is old and shallow pool, overgrown by aquatic vegetation. Both other large (each about 0.5 ha) pools were recently (1991–96) restored and are relatively fresh and with vegetation only near banks. Findings in larger pools correspond with observation of Ložek (1986) in Slovakia and inhabiting biotopes are different to biotopes which inhabits A. leucostoma and A. spirorbis. Especially in restored two pools was A. septemgyratus very abundant and was eudominant mollusc. A occurrence of A. septemgyratus in the Moravia is surprising and further research will be directed to study of population of this rare species (especially in restored pools and their surroundings).

Figs 3–4. 3 – reproductive organs of Anisus septemgyratus (Rossmässler) from the same locality as in Fig. 2. AR – bursa copulatrix, MR – penis retractor muscle, O – oviduct, Pr – prostate gland, PTd – penis sheat, PTp – preputium, TR – truncus of bursa copulatrix, VD – vas deferens; scale: one segment = 1 mm. Orig. M. Horsák. 4 – male copulating organs of Anisus septemgyratus (Rossmässler) from the same locality as in Fig. 2. MR – penis retractor muscle, PTd – penis sheat, PTp – preputium; scale: one segment = 1 mm. Orig. M. Horsák.

233 Reproductive organs of about 30 specimen from second locality were dissected and results were compared with Hudec (1967). Our most important results are as follows: (1) Prostate gland is long and has many small folds. (2) Ratio between preputium and penis sheath is about 1:2. (3) Bursa copulatrix is long and slim. First and third features are according to Hudec (1967) and also our observations characteristic for A. septemgyratus and are different from A. leucostoma and A. spirorbis. Second feature is according to Hudec (1967) characteristic for A. spirorbis and for A. septemgyratus is documented ratio 1:1. This result is different to our observations and needs further research. According to our observation of inhabiting biotopes and especially of differences in reproductive organs is probable that this taxon is separate species, but is suitable to carry out further research on this taxon from other parts of Europe before final conclusion.

REFERENCES

BUCHAR J. 1982: Publication of faunistic data from Czechoslovakia. Věst. Čs. Společ. Zool. 46: 317–318. FALKNER G. 1989: Binnenmollusken. Pp.: 112–280. In: FECHTER R. & FALKNER G. (eds): Weichtiere. Europäische Meeres- und Binnenmolusken. München: Stenbachs Naturführer, Mosaik Verlag, 287 pp. GLÖER P. & M EIER-BROOK C. 1998: Süsswassermollusken (Ein Bestimmungsschlüssel für die Bundesrepublik Deutschland) 12. Auflage. Hamburg: Deutscher Jugendbund für Naturbeobachtung, 136 pp. HUDEC V. 1967: Bemerkungen zur anatomie von arten aus der gattung Anisus Studer, 1820 aus slowakischen populationen (Mollusca, Pulmonata). Biológia (Bratislava) 22: 345–363. LOŽEK J. 1986: [From the Red Data Book of our molluscs – where does Anisus septemgyratus find refuge?]. Živa 34: 143 (in Czech). PIECHOCKI 1979: Mieczaci (Mollusca). Slimaki (Gastropoda). Fauna Slodkow. Pol. 7, Warszava-Poznan: Państwowe wydawnictwo naukowe, 187 pp (in Polish). ZHADIN V. I. 1952: Molljuski presnych i solonovatych vod SSSR [Molluscs of freshwater and saltwater of USSR]. Moskva-Leningrad: Izd. AN SSSR, 376 pp (in Russian).

234 Acta Soc. Zool. Bohem. 66: 235–239, 2002 ISSN 1211-376X

An immature stonefly from Lower Miocene of the Bílina mine in northern Bohemia (Plecoptera: Perlidae)

Jakub PROKOP

Department of Zoology, Charles University, Viničná 7, CZ–128 44, Praha 2, Czech Republic and Department of Palaeontology, Charles University, Albertov 6, CZ–128 43 Praha 2, Czech Republic; e-mail: [email protected]

Received May 18, 2002; accepted September 3, 2002 Published November 4, 2002

Abstract. The first record of an immature stonefly (Perla cf. burmeisteriana Claassen, 1936) from the Lower Miocene of the Bílina mine in northern Bohemia (Czech Republic) is described and illustrated. Its occurrence with supposed palaeoenvironmental aspect of fossilization is outlined. Taxonomy, fossil, description, Insecta, Plecoptera, Perlidae, Tertiary, Lower Miocene, Czech Republic, Central Europe

INTRODUCTION Fossil stoneflies are extremely rare in Cenozoic fossil record and have not been found in Tertiary of the Czech Republic until present. The oldest stoneflies are known from Early Permian. The family diversity culminated in Jurassic and declined in Early Cretaceous. The general lack of fossil representatives especially in Tertiary deposits is probably due to different living conditions preferring running waters throughout their history. However, it is in contrary to a number of supposed lentic taxa in Mesozoic (Sinitshenkova 1997). During Tertiary period, the palaeolakes were mainly oligotrophic or stagnant waters. In these lakes, the running water elements were drifted by water current, e. g., streams. Only a few specimens of family Perlidae were found in fossil record. The oldest taxon is Sinoperla abdominalis Ping, 1928 from the Early Cretaceous of China. Several larvae and adults are described from Baltic amber (Eocene) and attributed to the recent genus Perla Geoffroy, 1762 (Carpenter 1992). A larva from the Oligocene of Southwestern Montana (USA) is attributed to the genus ?Acroneuria Pictet, 1841. The classical locality of Bílina mine (50° 34’ N, 13° 45’ E) is geographically situated in northwestern Bohemia of the Czech Republic (see Fig. 1). From stratigraphical point of view it belongs to the Lower Miocene (Eggenburgian/Ottnangian) of the Most Formation. The insect fauna is preserved in the three fossiliferous horizons above coal seam (Clayey Superseam Horizon, Delta Sandy Horizon, Lake Clayey Horizon) reflecting different sedimentary and palaeoenvironmental conditions (Rajchl & Uličný 1999, Prokop 2002). The paleobotanical record and possible reconstruction of vegetation on Clayey Superseam Horizon was previously outlined (Kvaček 1998, Sakala 2000). The nomenclature of larvae structures followed Theischinger (1991), Baumann (1987) and Raušer (1980).

235 SYSTEMATIC PALAEONTOLOGY Perlidae Latreille, 1802 Perla cf. burmeisteriana Claassen, 1936 (Figs 2, 3)

DESCRIPTION. Larval body flattened, overall length about 16.6 mm. Head with distinctly transverse posterior occipital ridge. Pronotum rectangular (5.3 mm long and 2.1 mm wide) with clear marginal groove separating marginal flanges; mesonotum (2.8 mm long and 6.2 mm wide) and metanotum (2.6 mm long and 6.0 mm wide) of about same size with well-developed wing pads. Medial dorsal suture distinctly present on all thoracic segments. Abdomen elongate, (9.2 mm long and 3.8 mm wide) with ten visible dorsal segments; tenth segment shorter than ninth with medial apical tip between basally thick cerci. A visible pattern of dark and light spot coloration. DISCUSSION. The general habitus of large, dorsoventrally flattened body and dorsal color spot pattern resembles family Perlidae, especially genus Perla. The shape of the pronotum is similar to the recent abundant palaearctic species P. burmeisteriana Claassen, 1936. Nevertheless, a precise classification is not possible because of the lack of the head and of the ventral branched gills on thoracic segments.

Fig. 1. Geographical position of northwestern Bohemia within Europe (A), detailed map of the Most Basin (B), 1 – Bílina mine.

236 Lewis & Gundersen (1987) described ?Acroneura sp., an immature stonefly from Ruby River Basin (Oligocene) of Southwestern Montana, USA. The specimen is very incomplete, smaller in size and differs mainly from our specimen in the absence of the wing pads and a different abdom- inal coloration. The nymphs of Perlidae described from the Baltic amber as Perla sp. have different structure and shape of pronotum. They show thoracic gills that are not preserved in specimen described here. The other fossil record of Perlidae is generally based on adult wing venation. There is adult of Dominiperla antigua Stark et Lentz, 1992 from Dominican amber and Eoperlites paradoxus Haupt, 1956, which is probably a fragment of wing of a Fulgoromorpha from the Eocene of Geiseltales in Germany (Haupt 1956, Stark & Lentz 1992). It is extremely difficult to determine Cenozoic fossils relative to modern taxa after the immature stages. Thus, this specimen is left in open nomenclature.

Figs 2–3. Perla cf. burmeisteriana Claassen, specimen ZD0185 – photo and line drawing. Scale 3 mm.

237 MATERIAL EXAMINED. Specimen No. ZD0185 (Doly Bílina coll., Bílina, Czech Republic), a nearly complete larvae (imprint) in dorsal view, posterior part of head, thorax, fragments of prothoracic and mesothoracic femora present, abdomen with distinct segmentation and basal part of cerci preserved, the coloration pattern is also preserved.

LOCALITY. Bílina mine near Bílina, Czech Republic. AGE AND LAYER. Lower Miocene (Eggenburgian/Ottnangian), Most Formation, Clayey Superseam Horizon.

CONCLUSIONS The presence of this specimen indicates an aquatic environment. Stonefly nymphs are predators that occur mainly in running water. The recent species preferably inhabit of small streams to large rivers but they are found also in cold ponds and lakes. The family Perlidae comprises about 400 recent species that are widely distributed in the northern hemisphere with a few genera extending into the southern hemisphere in Africa and South America. The major part of the genera is restrict- ed in the East Palaearctic (Baumann 1987, Nelson 1996). The history and living conditions of modern Plecoptera started with the break up of Pangaea (Zwick 2000). This fossil is the unique record of a stonefly in the Bilina paleolake. We can suspect that this element is allochthonous and was probably transported into basin by an occasional flooding from early uplands. This is supported by the fish fauna (M. Böhme pers. comm.), plant megafossils (Pinus ornata Stemberk) and pollen analysis significantly confirmed from Lake Clayey Horizon. The evidence of facultative foothills elements in Clayey Superseam Horizon is not clearly documented, e. g., pollen analysis (Pinaceae). However, a stonefly is probably indicative of life apart from back swamp or lake.

A c k n o w l e d g e m e n t s The author is grateful to Zlatko Kvaček (Charles University, Praha) and André Nel (Museum national d’Histoire naturelle) for suggestive advices and to Zdeněk Dvořák (Doly Bílina) for the loan of the material. My express thanks goes to Miss Zuzana Čadová (scientific illustrator, Charles University, Praha) for the magnificent habitual drawing. The research was supported by grants of the Ministry of Schools J13/98-113100004 and GAČR 205/01/ 0639.

REFERENCES

BAUMANN R. W. 1987: Order Plecoptera. Pp.: 186–195. In: STEHR F. W. (Ed.): Immature insects. Dubuque, Iowa: Kendall Hunt, 754 pp. CARPENTER F. M. 1992: Order Perlaria Latreille, 1802. Pp.: 93-97. In: MOORE R. C. (ed.): Treatise on invertebrate paleontology, part R, Insecta (3–4). Lawrence: The University of Kansas, 655 pp. HAUPT H. 1956: Beitrag zur Kenntnis der Eozanen Arthropodenfauna des Geiseltales. Nova Acta Leopoldina, (N. F.) 18(128): 1–90. KVAČEK Z. 1998: Bílina: a vindow on Early Miocene marshland environments. Rev. Palaeobot. Palynol. 101: 111–113. LEWIS S. E. & GUNDERSEN R. W. 1987: An immature stonefly (Plecoptera: Perlidae) from the Ruby River basin (Oligocene) of Southwestern Montana. Occ. Pap. Paleobiol. St. Cloud State Univ. 1(1): 1–4. NELSON C. R. 1996: Tree of Life-Web project. Home page on internet: http://tolweb.org/tree?group=Plecoptera &contgroup=Neoptera. PROKOP J. 2002: Remarks on palaeoenviromental changes based on reviewed Tertiary insect associations from the Krušné hory piedmont basins and the České středohoří Mts. in northwestern Bohemia (Czech Republic). Acta Zool. Cracow. 45: in press. RAJCHL M. & ULIČNÝ D. 1999: [Deposital model of the Bílina Delta (Miocene, Most Basin, Czech Republic)]. Zpravod. Hnědé Uhlí 1999(3): 15–42 (in Czech).

238 ROSS A. J. & JARZEMBOWSKI E. A. 1993: Arthropoda (Hexapoda; Insecta). Pp: 363–426. In: BENTON M. J. (Ed.): The Fossil Record 2. London: Chapman & Hall, 845 pp. RAUŠER J. 1980: [Order Plecoptera]. Pp.: 86–132. In: ROKOŠNÝ R. (ed.): Klíč vodních larev hmyzu [Identification key of water insect larvae]. Praha: Academia, 521 pp. SAKALA J. 2000: Flora and vegetation of the roof of the main lignite seam in the Bílina Mine (Most Basin, Lower Miocene). Acta Mus. Natl. Pragae, S. B, Histor. Natur. 56: 49–84. SINICHENKOVA N. D. 1997: Palaeontology of stoneflies. Pp.: 561–565. In: LANDOLT P. & S ARTORI M. (eds.): Ephemeroptera & Plecoptera: Biology – Ecology – Systematics. Fribourg: MTL, 569 pp. STARK B. P. & LENTZ D. L. 1992: Dominiperla antigua, new genus and species (Plecoptera: Perlidae): the first stonefly from Dominican amber. J. Kansas Entomol. Soc. 65(1): 93–96. THEISCHINGER G. 1991: Plecoptera (Stoneflies). Pp.: 311–319. In: CSIRO M. (ed.): The insects of Australia. A textbook for a students and research workers. 2nd ed., Vol. 1. Melbourne: Melbourne University Press, 542 pp. ZWICK P. 2000: Phylogenetic system and zoogeography of the Plecoptera. Ann. Rev. Entomol. 45: 709–746.

239 Acta Soc. Zool. Bohem. 66: 240, 2002 ISSN 1211-376X

BOOK REVIEW

SERVICE M.W. (ed.): Encyclopedia of Arthropod-transmitted Infections of Man and Domesticated Animals. Wallingford, Oxon: CABI Publishing, a division of CAB International, 2001. XVI+579 pp. Format 170×240 mm. Hardback. Price Lstg 99.50 (USD 185.00). ISBN 0 85199 473 3 The editor is Emeritus Professor of Medical Entomology at the Liverpool School of Tropical Medicine. He has been advised by the five international advisors – foremost authorities in the field: R. W. Ashford, C. H. Calisher, B. F. Eldridge, T. V. Jones, and G. Wyatt. The project of this publication involved 88 authors of 19 countries: physicians, veterinarians, parasitologists, entomolologists and zoologists. It is pointed up in the preface that this is an encyclopedia, not a specialized medical or veterinary textbook, and so the aim has been to present up-to- date basic information on the transmission of a broad range of infections causing serious illnesses. Vertebrates, including humans, become infected when they are bitten by an infected arthropod taking a blood meal. The enormous increase in global travel is one of the major factors in the spread of infectious diseases, such as West Nile virus which has emerged in temperate regions of Europe and North America. This encyclopedia contains 150 entries, describing arboviral, viral, bacterial, rickettsial and spirochaetal infections, protozoal and filarial infections. Entries range from 100 words to 5000 words, they are arranged in alphabetical order starting with aegyptianellosis and concluding with the Zika virus. Arboviral and viral infections discussed include infections as the African horse sickness, African swine fever, the Chikungunya virus, the Colorado tick fever, Ilesha virus, Ilheus virus, Issyk-Kul virus disease, Jamestown Canyon virus, Japanese encephalitis, Keystone virus, haemorrhagic fevers, Powassan encephalitis, Rocio encephalitis, Ross River virus, Venezulean equine encephalitis, vesicular stomatitis, West Nile virus, and many more. Bacterial, rickettsial and spirochaetal infections incorporate plague, tularaemia, endemic typhus, epidemic typhus, Rocky Mountain spotted fever, tick-borne typhuses, avian borreliosis, Lyme borreliosis, tick-borne and louse-borne relapsing fevers. Entries on protozoal and filarial infections are concerned with trypanosomes as aetiologic agents of African sleeping sickness and the Chagas disease in humans, and Trypanosoma species in animals affecting the livestock in tropical regions. Entries dedicated to parasitic diseases present the malaria in humans and birds, leishmaniases, babesioses and theilerioses in humans, cattle, sheep and goats, equines and in dogs. Animal and human filarial infections transmitted by bloodsucking arthropods are presented here by bancroftian and brugian filariasis, dirofilariasis, mansonelliasis, onchocerciasis, parafilariasis, stephanofilariasis, and others. Detailed entries provide insights into diverse arthropods – insects and arachnids, transmitting the named infections. Emphasis is given to mosquitoes, black-flies, biting midges, eye-flies (Chloropidae), fleas, horse-flies, mosquitoes, sand-flies, stable-flies, tse-tse flies (Glossinidae), to ticks and mites, and others. Information on diseases include distribution, aetiological agent, transmission cycles, diagnosis, clinical symptoms, treatment and control measures. Following each entry is a selected, mostly periodical or monographic bibliography and more specialized textbooks relevant to the entries, to aid further reading on the topic. Entries dealing with arthropods constitute a highlight of identification, biology, transmitted diseases and control. The volume is extensively illustrated by schematic line drawings and black-and-white photographs: featured are diagrams of natural cycles of transmission, adult forms and developmental stages of ectoparasitic vectors: insects and arachnids, life cycles of causative agents and factors involved in pathogenesis, light and electron microphotographs, genetic processes, maps of worldwide distribution of various infections, views of terrestrial biomes, pathological and histopathological abnormalities in humans and animals, clinical conditions, skin lesions, and more. In addition, there are numerous summary-type tables offering overviews of diverse microorganisms, characteristics of symptoms, classification of drugs, dosages of insecticides, and more. This encyclopedia presents a most comprehensive up-to-date handbook essential to anyone who is interested in finding out transmits of infectious agent, where it is found and whether it can be cured or prevented. It covers a broad range of related disciplines including human and veterinary medicine, epidemiology, epizootiology, immunology, microbiology, virology, parasitology and entomology. Jindřich Jíra

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