Diversity of freshwater Cladoceran species (Crustacea: Branchiopoda) in South Korea
Diversity of freshwater Cladoceran species (Crustacea: Branchiopoda) in South Korea
Journal of Ecology and Environment. 2015. Aug, 38(3): 361-366
Copyright © 2015, The Ecological Society of Korea
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Licens ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
  • Received : April 13, 2015
  • Accepted : May 13, 2015
  • Published : August 28, 2015
Export by style
Cited by
About the Authors
Hyungi Jeong
Nakdong River Environment Research Center, Goryeong 717-873, Korea
Alexey A. Kotov
A.N. Severtsov Institute of Ecology and Evolution, Leninsky Prospect 33, Moscow 119071, Russia
Wonchoel Lee
Department of Life Science, Hanyang University, Seoul 133-791, Korea
Raehyuk Jeong
Department of Life Science, Hanyang University, Seoul 133-791, Korea
Seuk Cheon
Nakdong River Environment Research Center, Goryeong 717-873, Korea

We investigated cladoceran fauna from 71 study areas in South Korea. Sixty-two taxa were found, of which there were 30 planktonic and 25 littoral-benthic cladoceran species. In the present study, taxa of cladocera were identified by biographical traits. Species endemic to the Far East were found in the northernmost areas of South Korea, whereas Palearctic species were found in the southernmost areas. Generally, coexistence of cladoceran species in northern and southern areas was observed, implying possible faunistic complexes of cladocera in various areas of South Korea. We believe that further studies conducted in different habitats will greatly expand our knowledge of the biodiversity of cladocera in South Korea.
Cladocera is one of the major zooplankton groups in various freshwater habitats, where few other species have managed to penetrate. Cladocerans generally prefer lentic water, and are therefore uncommon in lotic water bodies. Most biologists regard cladocerans as planktonic (as represented by the well-known genus Daphnia ); however, they tend to be more diverse in the littoral zone, living among various freshwater macrophytes ( Whiteside and Harmsworth 1967 , James et al. 1998 , Maia-Barbosa et al. 2008 ). Some species live in the profundal zone of large lakes, ground waters, caves, and even in the cavities between leafs of bromeliad plants, and in small drops of water, on the mosses of cloud tropical forests ( Sinev 2002 ). Because of their adaptability to various habitats, and the relative lack of data available on the various habitat types, we assume that there is a considerably greater diversity of freshwater cladocera than currently described ( Jeong et al. 2013 ).
The order Cladocera comprises four sub-orders: Anomopoda Sars, 1865, Ctenopoda Sars, 1865, Haplopoda Sars, 1865 and Onychopoda Sars, 1865 ( Fryer 1987 ). Each of them can be alternatively identified as Anomopoda, Ctenopoda, Haplopoda, and Onychopoda, respectively. These sub-orders further comprise more than 700 species and 100 genera. Over the last two decades, significant progress has been made in the study of some genera of Ctenopoda ( Korovchinsky 2004 ), Anomopoda ( Smirnov 1992 , 1996 , 1998 , Kotov and Štifter 2006 , Van Damme and Dumont 2008 , Kotov 2009 , Sinev 2009 ) and Haplopoda ( Korovchinsky 2009 ), using morphological analysis. Although considerable progress has been made recently in cladoceran taxonomy, there are still many gaps in our knowledge. According to Forró et al. (2008) , overall cladoceran species richness is probably up to four times higher than what is currently known.
Much work is required of cladoceran taxonomists in different regions worldwide ( Korovchinsky 2013 ). Progress in the classification of Cladocera needs to be accompanied by studies of the regional fauna of the Iberian Peninsula ( Alonso 1996 ). Besides the studies of Uéno (1937) and Manujlova (1964) , cladocera of the northern part of East Asia have not garnered much attention, despite its tremendous diversity. As a result, the biology of freshwater zooplankton is poorly understood, outside of the Nearctic and Western Palearctic ( Benzie 2005 ).
Although in recent years, endemic species or lineages have not been reported in Asia, eastern Russia, and surrounding territories, Glagolev (1995) and Ishikawa ( 1895a , 1895b , 1896 ) have described several species endemic to Asia. Similar studies are lacking in the Holarctic, in contrast to impressive advances being made in tropical and subtropical countries ( Elmoor-Loureiro 2000 , Maiphae et al. 2008 ). From a zoogeographical point of view, the diversity of cladocera in the Palearctic is greater than that in any other zone ( Frey 1987 , Forró et al. 2008 ). Consequently, the Korean Peninsula, which is a part of the Paleractic ecozone, is likely to have a very high diversity of cladocera.
This paper aims to present a brief overview of cladoceran fauna, based on zoogeographical traits, and a quantitative estimation of cladoceran species diversity in the Korean Peninsula.
- Study sites
In 71 sites in South Korea ( Fig. 1 ), samples were taken from different biotopes, including lakes, swamps, ponds, brackish waters, and rice paddies, over the period 2009-2014. In the case of small ponds or puddles, a total sample was obtained by combining smaller samples from different parts of the body of water. In the case of larger bodies of water, several samples were taken from different biotopes. The samples were taken using plankton and dip nets that were placed over macrophytes and near-shore substrates. Because of insufficient data on abiotic factors, environmental data were excluded from this study.
PPT Slide
Lager Image
Map of the Korean Peninsula with localities sampled during study period (+, valley; △, rice paddy; □, pond; ○, swamp; ★, reservoir; ⓧ, lake; ▲, stream; ●, river).
- Sample collection and Identification
Each sample was filtered through nets with a mesh size of approximately 30–100 μm. All filtered samples were thoroughly washed with 95% alcohol. Determination of cladoceran classification was accomplished swith the aid of a binocular stereoscopic microscope at 10–40× magnification, and they were further observed under a compound optical microscope, Zeiss Axioscop II (Carl Zeiss, Germany).
This study used current species names, from the most recent available literature and published papers in Korea ( Jeong et al. 2014 , Kotov et al. 2012 ), in addition to the checklist of FADA (2013) .
- Diversity estimation
All data for continental South Korea were compiled ( Fig. 1 ), and EstimateS 9.0 ( Longino and Colwell 1997 ) was used to estimate total species richness of cladocera in the region. Accumulation curves were plotted by computing Chao 2 estimators (EstimateS). In cases of a relatively small sample size, the estimates for the species richness were computed by using 95% confidence intervals.
- Cladoceran fauna from South Korea
We identified 62 cladoceran species in 71 locations, 55 of which were identified to the species level. In eight cases, we were able to identify the taxon to the generic level only ( Table 1 ). In a few cases, specimens either were juveniles, or were deformed, displaying morphologically intermediary features of the known taxa.
Cladocerans sampled in study sites throughout South Korea during the period 2009–2014
PPT Slide
Lager Image
Cladocerans sampled in study sites throughout South Korea during the period 2009–2014
Chydorids were the most diverse group of cladocera, followed by daphniids and sidids ( Table 1 ). Other families were represented by fewer species ( Tables 1 and 2 ). These results were quite expected, as chydorids compose approximately half of all cladocerans worldwide ( Forró et al. 2008 ). The frequency of planktonic species was relatively high ( Table 2 ). Among the cladocerans sampled, 30 ecological groups were identified as planktonic species (both pelagic and sub-littoral), and 25 identified as littoral and benthic species ( Table 2 ).
List of cladocerans found according to each habitat type (The number of sites found are represented within each habitat type)
PPT Slide
Lager Image
List of cladocerans found according to each habitat type (The number of sites found are represented within each habitat type)
Normally, the number of littoral cladocerans is two to three times higher than that of pelagic cladocerans. Our results may have been influenced by insufficient sampling of the littoral zone. We also assume that the list of planktonic cladocerans is more complete than that of littoral cladocerans. Many species which were not definitively identified by Yoon (2010) , were identified in recent studies ( Jeong et al. 2012 , 2013 , 2014 , Kotov et al. 2012 ). These apparent differences could be attributed to varying sample sizes, sampling frequencies, and seasonal variations at the times of sampling, across the different studies. Considerably more research is necessary, to compile a comprehensive list of Korean cladocerans.
- Quantitative estimation of the cladoceran diversity of South Korea
Cumulative curves of the species accumulation are represented in Fig. 2 . The best model for the estimation of total species richness is Chao 2, yielding minimum variance and giving a prediction of 97 species in contrast to the 62 that were identified in the present study. Neither curve should plateau, because as more samples are taken, there should be an expected corresponding increase in the number of revealed and predicted taxa, according to the Chao 2 model ( Fig. 2 ).
PPT Slide
Lager Image
Species accumulation curves for cladoceran taxa in South Korea (The dotted line represents the values for the Chao2 species richness estimator. The solid line is the sample-based rarefaction curve).
- Diversity of freshwater cladocera
According to Jeong et al. (2014) , there are 85 valid cladoceran species in South Korea. Some taxa identified were difficult to distinguish morphologically, and were excluded from consideration. Cladoceran fauna of the Eastern Hemisphere (including Korea, China, parts of the Russian border, Japan, Vietnam, and Thailand) consists of two main categories ( Fig. 3 ): One category is the widely dispersed Palearctic species. The emerging taxa (e.g., Sida ortiva , Simocephalus serrulatus , Simocephalus mixtus , and Acroperus harpae ) are known in eastern and western Palearctic regions, and have been recorded in South Korea. The other category is endemic to East Asia, having a different latitudinal distribution and showing seasonal variation between the local areas and pan-Eastern Asia ( Kim 1988 , Yoon 2010 , Kotov et al. 2012 , Korovchinsky 2013 ). Some taxa (e.g., Kuruzia longirostris ) are distributed along the northernmost areas of Korea.
PPT Slide
Lager Image
Concept of distribution of cladocerans in South Korea.
In contrast, one cladoceran taxon, Pseudosida szalayi ( Kotov et al. 2012 ), which can be found in South Korea, can also be found in tropical countries (e.g., Sri Lanka, India, and some parts of China), as well as in the Amur basin in Eastern Russia ( Korovchinsky 2010 ). The distribution of these cladocerans indicates that Korea is part of a zone of special interest to cladocerologists. After further taxonomic revision, the number of cladoceran species endemic to South Korea will most likely increase, as can be inferred from Fig. 2 .
In conclusion, further studies of cladoceran species, are necessary in Eastern Asia, particularly along the border of the Palearctic and Oriental zones, including South Korea ( Kotov et al. 2012 ). Recent studies prove that previously unidentified species are being recorded throughout South Korea ( Jeong et al. 2012 , 2013 , Kotov et al. 2012 ). The present study reveals that South Korea has a potentially vast biodiversity of cladocera. Further studies and revisions of other cladoceran taxa in the region, will likely show a significant increase in the current number of endemic taxa.
This study was supported by the Post-Doctoral Fellowships Program (grant number: 1200-1234-303-210-13) of Nakdong River Environment Research Center, the National Institute of Environmental Research, Republic of Korea.
Alonso M 1996 Crustacea Branchiopoda. Fauna Ibérica 7. Museo Nacional de Ciencias Naturales Consejo Superior de Investigaciones Científicas Madrid
Benzie JAH 2005 The genus Daphnia (including Daphniopsis) (Anomopoda: Daphniidae). Guides to the identification of the microinvertebrates of the continental waters of the world 21 Kenobi Productions, Ghent and Backhuys Publishers Leiden
Elmoor-Loureiro LMA 2000 Brazilian cladoceran studies: Where do we stand? Nauplius 8 117 - 131
2000 Brazilian cladoceran studies: Where do we stand? Nauplius 8 117 - 131
Forró L , Korovchinsky NM , Kotov AA , Petrusek A 2008 Global diversity of cladocerans (Cladocera; Crustacea) in freshwater Hydrobiologia 595 177 - 184    DOI : 10.1007/s10750-007-9013-5
Frey DG 1987 The taxonomy and biogeography of the Cladocera Hydrobiologia 145 5 - 17    DOI : 10.1007/BF02530260
Fryer G 1987 Morphology and the classification of the socalled Cladocera Hydrobiologia 145 19 - 28    DOI : 10.1007/BF02530261
Glagolev SM , Alekseev V R 1995 A Key-book of the Freshwater Invertebrates of Russia and its Vicinity Zool Inst Press St. Petersburg Genus Daphnia 48 - 58
Ishikawa C 1895 Phyllopod Crustacea of Japan. Daphnia Morsei The Zoological Magazine, Org Zool Soc Tokyo 7 137 - 142
Ishikawa C 1895 Phyllopod Crustacea of Japan. Daphnia Whitmani The Zoological Magazine, Org Zool Soc Tokyo 7 147 - 154
Ishikawa С 1896 Phyllopod Crustacea of Japan. Moina weismani n. sp The Zoological Magazine, Org Zool Soc Tokyo 7 1 - 6
James MR , Weatherhead M , Stanger C , Graynoth E 1998 Macroinvertebrate Distribution in the Littoral Zone of Lake Coleridge, South Island, New Zealand-effects of habitat stability, wind exposure, and macrophytes N Z J Mar Freshw Res 32 287 - 305    DOI : 10.1080/00288330.1998.9516826
Jeong HG , Kotov AA , Lee W 2012 A new species of the genus Ilyocryptus Sars, 1862 (Cladocera: Anomopoda: Ilyocryptidae) from the East Asian Palearctic Zootaxa 3475 36 - 44
Jeong HG , Kotov AA , Lee W 2013 A new species of the genus Pleuroxus Baird (Cladocera: Anomopoda: Chydoridae) from Jeju Island, South Korea Zootaxa 3666 031 - 040    DOI : 10.11646/zootaxa.3666.1.3
Jeong HG , Kotov AA , Lee W 2014 Checklist of the freshwater Cladocera (Crustacea: Branchiopoda) of South Korea Proc Biol Soc Wash 127 216 - 228    DOI : 10.2988/0006-324X-127.1.216
Kim IH 1988 Key to the Korean freshwater Cladocera Korean J Syst Zool 2 43 - 65
Korovchinsky NM 2004 Cladocerans of the Order Ctenopoda of the World Fauna (Morphology, Systematics, Ecology, Biogeography) KMK Press Moscow
Korovchinsky NM 2009 The genus Leptodora Lilljeborg (Crustacea: Branchiopoda: Cladocera) is not monotypic: description of a new species from the Amur River basin (Far East of Russia) Zootaxa 2120 39 - 52
Korovchinsky NM 2010 A taxonomic revision of Pseudosida szalayi Daday, 1898 (Crustacea: Cladocera: Sididae) over its Asian range, with focus on the Northernmost populations first recorded from the Amur River Basin (Far East of Russia) Zootaxa 2345 1 - 18
Korovchinsky NM 2013 Cladocera (Crustacea: Branchiopoda) of South East Asia: History of exploration, taxon richness and notes on zoogeography J Limnol 72 109 - 124
Kotov AA 2009 A revision of Leydigia Kurz, 1875 (Anomopoda, Cladocera, Branchiopoda), and subgeneric differentiation within the genus Zootaxa 2082 1 - 84
Kotov AA , Jeong HG , Lee W 2012 Cladocera (Crustacea: Branchiopoda) of the South-east of the Korean Peninsula, with twenty new records for Korea Zootaxa 3368 50 - 90
Kotov AA , Štifter P 2006 Cladocera: family Ilyocryptidae (Branchiopoda: Cladocera: Anomopoda). Guides to the identification of the microinvertebrates of the Continental Waters of the World. Vol. 22 Kenobi Productions, Ghent and Backhuys Publishers Leiden
Longino JT , Colwell RK 1997 Biodiversity Assessment using Structured Inventory: Capturing the ant fauna of a tropical rain forest Ecol Appl 7 1263 - 1277    DOI : 10.1890/1051-0761(1997)007[1263:BAUSIC]2.0.CO;2
Maia-Barbosa PM , Peixoto RS , Guimaraes AS 2008 Zooplankton in littoral waters of a tropical lake: a revisited biodiversity Braz J Biol 68 1069 - 1078    DOI : 10.1590/S1519-69842008000500014
Maiphae S , Pholpunthin P , Dumont HJ 2008 Taxon richness and biogeography of the Cladocera (Crustacea: Ctenopoda, Anomopoda) of Thailand Int J Lim 44 33 - 43    DOI : 10.1051/limn:2008021
Manujlova EF 1964 The cladoceran fauna of the USSR Opredeliteli po faune SSSR 88 1 - 327
Sinev AY 2002 Place of a Central American bromeliad-inhabiting cladoceran Alona bromelicola Smirnov 1998, within the genus (Branchiopoda Anomopoda,Chydoridae) Arthropoda Sel 11 109 - 116
Sinev AY 2009 Discrimination between two sibling species of Acroperus (Baird, 1843) from the Palearctic (Cladocera: Anomopoda: Chydoridae) Zootaxa 2176 1 - 21
Smirnov NN 1992 The Macrothricidae of the world. Guides to the identification of the microinvertebrates of the Continental Waters of the world SPB Academic Publishing The Hague
Smirnov NN 1996 Cladocera: the Chydorinae and Sayciinae (Chydoridae) of the world. Guides to the identification of the microinvertebrates of the Continental Waters of the world SPB Academic Publishing Amsterdam
Smirnov NN 1998 A revision of the genus Camptocercus (Anomopoda, Chydoridae, Aloninae) Hydrobiologia 386 63 - 83    DOI : 10.1023/A:1003524414799
Uéno M 1937 Order Branchiopoda (Class Crustacea) Fauna Nipponica 9 1 - 135
Van Damme K , Dumont HJ 2008 Further division of Alona Baird, 1843: separation and position of Coronatella Dybowski & Grochowski and Ovalona gen. n. (Crustacea: Cladocera) Zootaxa 1960 1 - 44
Whiteside MC , Harmsworth RV 1967 Species diversity in chydorid (Cladocera) communities Ecology 48 664 - 667    DOI : 10.2307/1936514
Yoon SM 2010 Branchiopods:Arthropoda: Branchiopoda: Anostraca, Notostraca, Spinicaudata, Laevicaudata, Ctenopoda, Anomopoda, Haplopoda NIBR Incheon Invertebrate Fauna of Korea