Spatial patterns of distribution of meiofaunal and nematode assemblages in the Huvadhoo lagoon (Maldives, Indian Ocean)

Abstract

Huvadhoo Atoll is a little-known and generally uncontaminated atoll of the southern Maldives, although the human pressure is increasing. This study represents the first attempt to characterize the meiofaunal and nematode assemblages of its lagoon both from a taxonomic and functional point of view. The nematode assemblage was made up of a total of 131 genera in 33 families. Desmodoridae, Chromadoridae and Xyalidae represented the richest and most abundant families, followed in terms of abundance by Selachinematidae and Comesomatidae. The nematode richness was overall higher than that reported in the previous studies carried out in the Central part of the archipelago. The diversity patterns revealed higher values than those reported for the back-reefs platforms, so confirming the positive influence of the water depth on the biodiversity of the nematode assemblage. The statistical analysis highlighted a significant taxonomic difference of the assemblages between the stations characterized by fine and medium-coarse sands, respectively, in line with the auto-ecological preferences of the taxa detected. The use of some nematode descriptors for assessing the ecological quality status (EQS) of the lagoon has revealed a slight disturbance in the station close to Viligili, one of the most urbanized islands. However, the summarization of all the descriptors used allows the highlighting of the good EQS of the Huvadhoo lagoon. Thus, the results of this study may be taken as the starting point for the future monitoring of the potential and real impact of the anthropogenic activity on the area over time.

Checklist of free-living marine nematodes from intertidal sites along the central west coast of India

“…As part of the present study, many of these genera were encountered by us from sampled sites. Therefore, the similarities in nematode assemblages, in terms of dominant families and genera between geographically distant areas of Indian Ocean region indicate the existence of iso-communities as observed in other studies (Ansari et al 2012;Semprucci et al 2014). For example, Semprucci et al (2013) have reported the presence of sediment dwelling taxa (e.g., Richtersia, Ptycholaimellus and Molgolaimus) in Maldivian subtidal habitats and in our study area (central west coast of India), we encountered some of these sediment dwelling taxa across several sites, although both the areas are geographically separated from each other within the Indian Ocean region.…”

“…Some of the species reported by them, e.g., Anoplostoma sp., Daptonema sp., Sabatieria sp., Terschellingia longicaudata, Viscosia abyssorum, Sphaerolaimus sp., and Microlaimus sp., were also encountered in this study across intertidal study (Semprucci et al 2013). In a very recent paper, Semprucci et al (2014) studied the nematode assemblages from a lagoon in Maldives of Indian Ocean region and found that the most abundant and richest families were represented by Desmodoridae, Chromadoridae and Xyalidae. In our study we also report the presence of several nematode genera belonging to these families.…”

Taxonomic and functional biodiversity variations of meiobenthic and nematode assemblages across an extreme environment: a study case in a Blue Hole cave

“…The nematode assemblage biodiversity was higher above the chemocline level with values overall comparable to those reported in other areas of the Maldives (Semprucci et al 2010b(Semprucci et al , 2013(Semprucci et al , 2014. The dominant families and genera found in this study were typical of muds or fine sands worldwide (Heip et al 1985;Soetaert & Heip 1995;De Leonardis et al 2008;Semprucci et al 2010a;Muthumbi et al 2011).…”

“…However, little detailed information is available on the biology of this genus (Vanreusel et al 2010a), and its presence has been well documented in the subtidal sediments of Maldivian islands where the intricate physical micro-structure of the biogenic substrata seems to favour sediment-dwelling taxa like this one (Semprucci et al 2013(Semprucci et al , 2014. Bongers (1990) and Bongers et al (1991) proposed a classification of nematodes into colonisers (comparable to r-strategists, characterised by high tolerance to disturbance) and persisters (k-strategist, with low colonisation ability and tolerance to disturbance).…”

“…Despite the great variety of habitats in Maldives and the increasing level of their exploration and conservation strategies, data on meiobenthic assemblages are largely focused on shallow subtidal waters (Semprucci et al 2010b(Semprucci et al , 2013(Semprucci et al , 2014.…”