Composition of aquatic invertebrates associated with macrophytes in Lake Tonle Sap, Cambodia

Abstract

Faunal composition of aquatic invertebrate communities associated with submerged parts of several species of macrophytes were studied in different areas in littoral Lake Tonle Sap in Cambodia, with special reference to those in root systems (interrhizon) of a free-floating water hyacinth (Eichhornia crassipes). Nine phyla of invertebrates were collected, of which oligochaetes, shrimps and Limnoperna mussels were abundant along with meiobenthic crustaceans. The macrophyte-associated invertebrates in Lake Tonle Sap might be unique in having abundant sessile animals, such as sponges, bryozoans and Limnoperna mussels. The Limnoperna mussels attached to macrophytes were more abundant in offshore and inundated forest than in secluded vegetational stands toward the shoreline. It suggests that water movement can be an important factor determining the distribution and abundance of the sessile animals by controlling larval dispersions and might be associated with the hydrological characteristic of the lake, i.e., the lake opens to the large Mekong River with drastic seasonal changes in water level.

Structure and density population of the invasive mollusc Limnoperna fortunei associated with Eichhornia crassipes in lakes of the Middle Paraná floodplain

“…This coincides with the work done by Ohtaka et al (2011) in an inland lake in Cambodia, Southeast Asia, where they also found small L. fortunei (1.96-12.7 mm) attached only to E. crassipes roots even though there were other macrophytes available. Several studies have demonstrated the importance of filamentous substrates such as aquatic macrophytes and filamentous algae in the settlement of larvae and juveniles of marine and freshwater bivalve species (Bayne, 1964;Ackerman et al, 1994;Cáceres-Martínez et al, 1994;Harvey et al, 1995;Folino-Rorem et al, 2006).…”

Biophysical status of remnant freshwater floodplain lagoons in the Great Barrier Reef catchment: a challenge for assessment and monitoring

“…Boulton and Lloyd (1991) reported that the relatively large number of taxa they collected emphasised the importance of a range of macro-and microhabitats to faunal diversity in a floodplain ecosystem. Elsewhere in the tropics, 74 taxa have been recorded from 72 wetland sites in southern Brazil (Stenert and Maltchik 2007), 38 taxa from lagoons in Brazil's upper Paraná River (Thomaz et al 2008), 46 taxa (Heckman 1998) and35 taxa (Poi de Neiff et al 2009) from the Pantanal wetlands in Brazil, 24 taxa from wetlands of the Okavango Delta, Botswana (Appleton et al 2003), 43 taxa from Lake Taabo, Côte d'Ivoire (Kouamé et al 2011) and 22 taxa from Lake Tonle Sap, Cambodia (Ohtaka et al 2011). The estimate of 85 comparable taxa by Horwitz et al (2009) is derived from their review of 18 studies across a variety of wetland types; their complete list of 520 taxa from 176 families highlights inadequacies of richness estimates based on higher taxa.…”

Colonization by oligochaetes (Annelida: Clitellata) in decomposing leaves ofEichhornia azurea(SW.) Kunth (Pontederiaceae) in a neotropical lentic system

“…Unlike in other reports, in which Aulodrilus, Nais and Pristina were the most abundant oligochaetes (Smock and Stoneburner, 1980;Chauvet et al, 1993;Capello et al, 2004), in this study D. (D.) sawayai was the species with the greatest density. The environmental characteristics of aquatic systems (sediment particle size and oxygen concentration) and of the leaves (degree of protection against predators and availability of food resources) influence the species and density of the oligochaetes that colonize decomposing material (Xie et al, 2008;Ohtaka et al, 2010).…”