Spatial Patterns in Diversity and Distribution of Benthic Molluscs in a Weak Tidal Tropical Lagoon

Abstract

Spatial patterns in diversity and distribution of benthic molluscs in a weak tidal tropical lagoon in south-west Nigeria were investigated from samples collected in eight study stations distributed along the stretch of the lagoon for two consecutive years. The study also investigated selected environmental conditions of overlying water and sediment of the lagoon to establish the roles played by environmental variables. There was a significant variation (p < 0.05) in salinity values along the study stretch which was predicated on the existing gradient in salinity of the lagoon. Higher values of mud and Total organic content (TOC) of sediment occurred in upstream compared to values observed in downstream stations. Mollusc communities were significantly influenced by the spatial gradient in salinity and variability in sediment parameters. The downstream stations had brackish conditions, while the upstream stations were typically freshwater, leading to differences in the composition and abundance of molluscs. The downstream stations recorded higher density and diversity of mollusc compared to upstream stations. Our results suggest that benthic molluscs in Epe Lagoon show spatial patterns related to differences in environmental parameters.

Community Structure and Spatial Patterns of Soft-Bottom Macrozoobenthos in Oualidia Lagoon, Moroccan Atlantic

“…Despite the absence of a river, the taxonomic organization of the macrozoobenthic assemblages of Oualidia lagoon closely resembled that of an estuarine system, where the tidal regime plays a key structuring role (Cherkaoui et al 2003). In Oualidia lagoon, however, the main driving factor appear to be the combined influence of granulometry, temperature and salinity, which seems also to be a common trend in lagoon systems (Uwadiae 2013). However, the environmental factors controlling the species distribution may change from one paralic environment to another being, for example, vegetation and grain size in the Smir lagoon (Mediterranean coast of Morocco) (Chaouti and Bayed 2008), dissolved oxygen, temperature and salinity in the Sacca di Goro (Adriatic coast of Italy) (Mistri et al 2001), or temperature and depth in Monolimni lagoon (Mediterranean lagoon, Northern Aegean) (Kevrekidis 2004).…”

Arthropod Community Structure of Jaja Creek and Downstream Sections of Imo River in Uta Ewa Village, Akwa Ibom State, Nigeria

“…They eat a wide range of foods, including tree leaves, algae, wood, detritus, other invertebrates, and even some vertebrates like small fish and tadpoles (Reece and Richardson, 2000). Uwadiae (2018) reported a total abundance of 58 arthropod species in Epe Lagoon, Nigeria, including 16 species from ten (10) Families; Gammaridae, Corophidae, Penaeidae, Ocypodidae, Clibanaridae, Chironomidae, Gomphidae, Libellulidae, Baetoidae, Tenthredinidae. Ocypoda cursor, O. africana, Uca tangeri, Penaeus notialis, Sersama huzardi, Clibanarius africanus, C. senegalenses, C. chapini, Palaemonetes vulgaris, and Gammarus fasciatus were among the crustaceans recorded by Uwadiae (2018).…”

“…Uwadiae (2018) reported a total abundance of 58 arthropod species in Epe Lagoon, Nigeria, including 16 species from ten (10) Families; Gammaridae, Corophidae, Penaeidae, Ocypodidae, Clibanaridae, Chironomidae, Gomphidae, Libellulidae, Baetoidae, Tenthredinidae. Ocypoda cursor, O. africana, Uca tangeri, Penaeus notialis, Sersama huzardi, Clibanarius africanus, C. senegalenses, C. chapini, Palaemonetes vulgaris, and Gammarus fasciatus were among the crustaceans recorded by Uwadiae (2018). According to Uwadiae (2017), all of the crustaceans in the Epe Lagoon are estuary species, while members of the Family Chironomidae (Class: Insecta) were discovered to inhabit a saline region of the Lagoon, and all of the insect species found in Aber Estuary also occurred in the system's purely freshwater portion.…”

Stochastic evaluation of benthic biocoenosis as pollution assessment tool in a perturbed aquatic ecosystem

“…Most species of MPB and MBF recorded here have been reported in stressed environments. For example, the mollusc P. aurita is well known for its ubiquitous status in the Lagos Lagoon, it has been reported even in severely stressed conditions (Uwadiae, 2013). Molluscs are known to tolerate stressed conditions owning to their ability to adapt to relatively high turbidities and anaerobic conditions prevalent in most estuaries by the closure of their shells during such unfavorable conditions (Hart and Fuller, 1979;Constable, 1999).…”