1 Institute of Tropical Biology, Vietnam Academy of Science and Technology, Ho Chi Minh City 700000, Vietnam

2 Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi 100000, Vietnam

3 Institute of Fundamental and Applied Sciences, Duy Tan University, Ho Chi Minh City 700000, Vietnam

4 Faculty of Information Technology, Duy Tan University, Da Nang 550000, Vietnam


The Lo Go-Xa Mat is a national park in the southeastern region of Vietnam, which has a particularly high biodiversity and it includes different wetlands which are unique diverse in species composition. It can be categorized into two types: temporarily-seasonally and permanently flooded wetlands. Ta Not grassy marsh is representative of the seasonally flooded wetland. Whilst the diversity and ecology of plants and mammals are well documented, little or no information of the benthic ecology in the seasonally flooded wetland exist. This study aims to provide a new database of the nematode’s structure in the seasonally flooded wetland and its relation with environmental variables as well as detection of the ecological quality, considering nematodes as bioindicators. This work is the first investigation on nematodes communities in associate with some environmental variables in the Ta Not grassy marsh. The results showed that free-living nematodes in the Ta Not seasonally flooded grassy marsh are characterized by the high density (ranged from 235.01 to 898.43 inds.10cm-2) but rather low diversity. More specifically, the genus richness (S) ranged from 8.20 to 8.60. The observed Margalef’s species richness (d) was ranging from 1.07 to 1.53 and the Shannon-Wiener index (H') was measured from 2.36 to 2.52. In addition, the Pielou's evenness (J′) ranged from 0.55 to 0.68 and the Hill indices indicated average values ranging between 5.46- 5.84 for N1, between 4.32-4.60 for N2, and between 2.64-2.86 for Ninf. Specifically, our results indicated that deep level, pH, and NH4+ showed a significant correlation with the nematode density and bio-indices. The sediment of the Ta Not grassy marsh was assessed as in good conditions in all stations based on the Maturity Index of nematodes.

Graphical Abstract

Relationships between environmental variables and free-living nematode communities in seasonally flooded wetlands


  • The communities are characterized by the slightly high density, low diversity in comparison to other habitats, namely fresh and brackish;
  • The study observed the relationship between several environmental variables (such as depth, pH, NH4+) and the nematode’s density, and also bio-indices;
  • The sediment of the seasonally flooded wetland was assessed as good conditions in all stations based on the Maturity Index of nematodes. MI could be considered as a good index for the detection of the ecological quality status of sediments.


Ansari, K.G.M.T.; Manokaran, S.; Raja, S.; Lyla, P.S.; Khan, S.A., (2014). Interaction of free-living marine nematodes in the artificial mangrove environment (southeast coast of India). Environ. Monit. Assess., 186(1): 293-305 (13 pages).

Bezerra, T.N.; Decraemer, W.; Eisendle-Flöckner, U.; Hodda, M.; Holovachov, O.; Leduc, D.; Miljutin, D.; Mokievsky, V.; Peña Santiago, R.; Sharma, J.; Smol, N.; Tchesunov, A.; Venekey, V.; Zhao, Z.; Vanreusel, A., (2020). Nemys: World Database of Nematodes.

Bongers, T., (1988). De Nematoden van Nederland. Natuurhistorische Bibliotheek van de KNNV, Nr. 46. Stichting Uitgeverij van de Koninklijke Nederlandse Natuurhistorische Vereniging, Utrecht (408 pages).

Bongers, T., (1990). The maturity index: An ecological measure of environmental disturbance based on nematode species composition. Oecologia. 83(1): 14-19 (6 pages).

Bongers, T., Ferris, H., (1999). Nematode community structure as a bioindicator in environmental monitoring. Trends Ecol. Evol., 14(6): 224-228 (5 pages).

Bongers, T.; Alkemade, R.; Yeates, G.W., (1991). Interpretation of disturbance-induced maturity decrease in marine nematode assemblages by means of the Maturity Index. Mar. Ecol. Prog. Ser., 76: 135-142 (8 pages).

Buckton, S.T.; Nguyen, C.; Ha, Q.Q.; Nguyen, D.T., (1999). The conservation of key wetland sites in the Mekong Delta. BirdLife International Vietnam Program Conservation Report No. 12. BirdLife International Vietnam Programme, Hanoi, Vietnam (114 pages).

Cai, L.; Fu, S.; Yang, J.; Zhou, X., (2012). Distribution of meiofaunal abundance in relation to environmental factors in Beibu Gulf, South China Sea. Acta Oceanolog. Sin., 31(6): 92-103 (12 pages).

Canty, A.; Ripley, B., (2016). Bootstrap R (S-Plus) Functions. R package version (16 pages).

Chinnadurai, G.; Fernando, O.J., (2007). Meiofauna of mangroves of the southeast coast of India with special reference to the free-living marine nematode assemblage. Estuar. Coast. Shelf. Sci., 72: 329-336 (8 pages).

Clarke, K.R.; Warwick, R.M., (2001). Change in Marine Communities: An Approach to Statistical Analysis and Interpretation (second ed), Primer-E Ltd., UK (176 pages).

Danovaro, R.; Dell'Anno, A.; Pusceddu, A.; Gambi, C.; Heiner, I.; Kristensen, R.M., (2010). The first metazoa living in permanently anoxic conditions. BMC Biol., 8(1): 2-10 (10 pages).

De Grisse, A.T., (1969). Redescription ou modifications de quelques technique utilis [a] es dan l'etude des n [a] ematodes phytoparasitaires.

Du, Y.; Gao, S.; Warwick, R.M.; Hua, E., (2014). Ecological functioning of free-living marine nematodes in coastal wetlands: an overview. Chinese Sci. Bull., 59(34): 4692-4704 (13 pages).

Dugan, P., (1993). Wetlands in danger. IUCN of the world conservation union. Mitchell Beazley, London (192 pages).

Dye, A.H., (1983). Composition and seasonal fluctuations of meiofauna in a southern African mangrove estuary. Mar. Biol., 73: 165-170 (6 pages).

Faber, J.; Fonseca, L.M., (2014). How sample size influences research outcomes.  Dental Press J. Orthod., 19(4): 27-29 (3 pages).

Finlayson, C.M.; Moser, M., (1991). Wetlands. International Waterfowl and Wetlands Research Bureau, Oxford (224 pages).

Górska, B.; Grzelak, K.; Kotwicki, L.; Hasemann, C.; Schewe, I.; Soltwedel, T.; Włodarska-Kowalczuk, M., (2014). Bathymetric variations in vertical distribution patterns of meiofauna in the surface sediments of the deep Arctic Ocean (HAUSGARTEN, Fram strait). Deep Sea Res. Part I Oceanogr. Res. Pap., 91: 36-49 (19 pages).

Gwyther, J., (2000). Meiofauna in phytal-based and sedimentary habitats of a temperate mangrove ecosystem − A preliminary survey. Proc. R. Soc. Vic., 112 (2): 137-151 (15 pages).

Harvey, R.G.; Loftus, W.F.; Rehage, J.S.; Mazzotti, F.J., (2011). Effects of canals and levees on Everglades ecosystems: circular. WEC304. IFAS Extension, University of Florida, Gainesville, FL (21 pages).

Ingels, J.; Tchesunov, A.V.; Vanreusel, A., (2011). Meiofauna in the Gollum Channels and the Whittard Canyon, Celtic Margin—how local environmental conditions shape nematode structure and function. PLoS One, 6(5): 1-15 (15 pages).

Liu, X.; Xu, M.; Hua, E.; Zhang, Z., (2016). Biodiversity of free-living marine nematodes in the southern Yellow Sea, China. J. Ocean U. China, 15(1): 1-10 (10 pages).

Majdi, N.; Traunspurger W., (2015). Free-living nematodes in the freshwater food web: a review. J. Nematol., 47(1): 28-44 (17 pages).

Moens, T.; Vincx, M., (1997). Observations on the feeding ecology of estuarine nematodes. J. Mar. Biolog. Assoc. U.K., 77: 211-227 (17 pages).

Moreno, M.; Semprucci, F.; Vezzulli, L.; Balsamo, M.; Fabian, M.; Albertelli, G., (2011). The use of nematodes in assessing ecological quality status in the Mediterranean coastal ecosystems. Ecol. Indic., 11(2): 328-336 (9 pages).

Ngo, X.Q.; Vanreusel, A.; Smol, N.; Chau, N.N., (2010). Meiobenthos assemblages in the Mekong estuarine system with special focus on free-living marine nematodes. Ocean Sci. J., 45(4): 213-224 (12 pages).

Ngo, X.Q.; Vanreusel, A.; Thanh, N.V.; Smol, N., (2007). Biodiversity of meiofauna in the intertidal Khe Nhan mudflat, Can Gio mangrove forest, Vietnam with special emphasis on free living nematodes. Ocean Sci. J., 42(3): 135-152 (18 pages).

Ngo, X.Q.; Nguyen, N.C.; Nic, M.; Larisa, P.; Ann, V., (2016). Intertidal nematode communities in the Mekong estuaries of Vietnam and their potential for biomonitoring. Environ. Monit. Assess., 188(2): 1-16 (16 pages).

Ngo, X.Q.; Nguyen, T.M.Y.; Nguyen, V.D.; Prozorova, L.; Smol, N.; Lins, L.; Vanreusel, A., (2018). Nematode communities in the Sai Gon River harbors in relation to tributyltin concentrations. Mar. Biodivers., 48(1): 139-151 (13 pages).

Ngo, X.Q.; Smol, N.; Vanreusel, A., (2013). The meiofauna distribution in correlation with environmental characteristics in 5 Mekong estuaries, Vietnam. Cah. Biol. Mar., 54: 71-83 (13 pages).

Ngo, X.Q.; Smol, N.; Vanreusel, A.; Nguyen, V.T.; Chau, N.N., (2008). One new and two unknown species of free-living marine nematodes from Can Gio mangrove forest, Ho Chi Minh city, Vietnam. J. Biol., 30(2): 1-11 (11 pages).

Pfannkuche, O.; Hjalmar, V., (1988). Sample processing, in: Higgins, R.P.; Thiel, H. (Eds.), Introduction to the Study of Meiofauna. Smithsonian Institution Press, Washington DC, USA (12 pages).

Ramsar Convention Bureau, (1990). Directory of Wetlands of International Importance. Ramsar Convention Bureau, Gland, Switzerland (782 pages).

Ramsar Handbooks, (2016).  An Introduction to the Convention on Wetlands, Ramsar Convention Secretariat, Gland, Switzerland. 5th edition (110 pages).

Ramsar list, (2020). Ramsar Vietnam. The convention entered into force in Viet Nam on 20 January 1989.

Salas, F.; Patrício, J.; Marcos, C.; Pardal, M.A.; Pérez-Ruzafa, A., (2006). Are taxonomic distinctness measures compliant to other ecological indicators in assessing ecological status?. Mar. Pollut. Bull., 52: 162-174 (13 pages).

Semprucci, F.; Losi, V; Moreno, M., (2015). A review of Italian research on free-living marine nematodes and the future perspectives on their use as Ecological Indicators (EcoInds). Mediterr. Mar. Sci., 16(2): 352-365 (14 pages).

Semprucci, F.; Moreno, M.; Sbrocca, S.; Rocchi, M.; Albertelli, G.; Balsamo, M., (2013). The nematode assemblage as a tool for the assessment of marine ecological quality status: a case-study in the Central Adriatic Sea. Mediter. Mar. Sci., 14(1): 48-57 (10 pages).

Shepherd, A.R.D.; Warwick, R.M.; Clarke, K.R.; Brown, B.E., (1992). An analysis of fish community responses to coral mining in the Maldives. Environ. Biol. Fish, 33(4): 367-380 (14 pages).

Tordoff, A.W.; Le, M.H., (2003). The avifauna of Lo Go-Xa Mat National Park, Tay Ninh Province. J. Biol., 25(4): 18-26 (9 pages).

Torres-Pratts, H.; Schizas, N.V., (2007). Meiofaunal colonization of decaying leaves of the red mangrove Rhizophora mangle, in southwestern Puerto Rico. Caribb. J. Sci., 43 (1): 127-137 (11 pages).

Tran, T.T.; Nguyen, L.Q. L.; Nguyen, T.M.Y.; Vanreusel, A.; Ngo, X.Q., (2018a). Biodiversity and distribution patterns of free-living nematode communities in Ba Lai River, Ben Tre province. J. Sci. Technol., 56(2): 224-235 (11 pages).

Tran, T.T.; Le, D.L.; Nguyen, T.M.Y.; Ngo, X.Q., (2018b). Assessment of the ecological quality status of sediment at the organic shrimp farming ponds in Ca Mau province by applying the abundance/biomass comparison (ABC) method on nematode communities. J. Sci. Technol. Develop., 21(3): 51-57 (6 pages).

Tran, T.T.; Nguyen, T.M.Y.; Ngo, X.Q.; Pham T.L., (2017). Effect of different water column depths on nematode communities in the mangrove-shrimp farming system, Ca Mau province. J. Mar. Sci. Technol., 17(4A): 269-278 (12 pages).

Triet, T.; Le, C.M.; Nguyen, P.N., (2004). Impacts of mimosa pigra on native plants and soil insect community in Tram Chim National Park, Vietnam, in: Julien, M.; Flanagan, G.; Heard, T.; Hennecke, B.; Paynter, Q.; Wilson, C. (Eds.), In Research and management of mimosa. CSRIO. Canberra, Australia (5 pages).

Vincx, M., (1996). Meiofauna in marine and freshwater sediments, in: Hall, G.S. (Eds.), Methods for the examination of organismal diversity in soils and sediments, Wallinfort UK (9 pages).

VNS, (2000). Soil quality: Determination of organic and total carbon after dry combustion (elementary analysis). Vietnamese National Standards (VNS) No. 6642:2000.

VNS, (2009). Soil quality: Method for the determination of bio-available nitrogen. Vietnamese National Standards (VNS) No. 5255:2009.

Warwick, R.M.; Platt, H.M.; Somerfield, P.J., (1998). Free living marine nematodes. Part III. Monhysterids. Cambridge University Press, Cambridge (296 pages).

Warwick, R., (1986). A new method for detecting pollution effects on marine macrobenthic communities. Mar. Biol., 92(4): 557-562 (6 pages).

Wieser, W., (1953). Die Beziehung zwischen Mundhöhlengestalt, Ernährungsweise und Vorkommen bei freilebenden marinen nematoden. Eine okologisch-morphologische studie, Arkiv für Zoologie vol. 4: 439-484 (45 pages).

Zeppilli, D.; Bongiorni, L.; Cattaneo, A.; Danovaro, R.; Santos, R.S., (2013). Meiofauna assemblages of the Condor Seamount (North-East Atlantic Ocean) and adjacent deep-sea sediments. Deep Sea Res. Part II Top. Stud. Oceanogr., 98: 87-100 (13 pages).

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