Gastropod Assemblages Associated with Habitat Heterogeneity and Hydrological Shifts in Two Shallow Waterbodies

Abstract

We aimed to determine the effects of water level and habitat heterogeneity on gastropod fauna in the littoral zone, and the differentiation of functional feeding guilds (FFG) of gastropods. Two periods were analyzed: 2012 (low water level, LWL) and 2013 (high water level, HWL) in the littoral zone of two shallow waterbodies (Sutla backwater, NW Croatia). Waterbody S1, covered with Ceratophyllum demersum, was sampled in the macrophyte stands, and the littoral benthal area, while waterbody S2, without macrophytes, was sampled only in the littoral benthal area. It was observed discovered that among the macrophyte stands in S1, gastropods were significantly more abundant during LWL. The same trend was observed in the littoral benthal area of S2. In contrast, gastropod abundance was higher in the littoral benthal area of S1 during HWL. Comparing gastropods in the two waterbodies, the abundance in S1 was ten times higher than in S2. The most abundant species was Gyraulus parvus, which accounted for 51–92% of the gastropods observed among the macrophytes of S1 and 86% in the adjacent benthic zone. Among the FFG groups, grazers (particularly those feeding on gymnamoebae and rotifers) had the largest proportion, followed by shredders feeding on small pieces of macrophytes. In our research, we indicate the important role of microhabitat diversity and submerged macrophytes as a rich food source for gastropods and safe shelter from predators.

Gastropod assemblages in the harsh environment of Mediterranean Dinaric karst intermittent rivers

“…Moreover, dense emergent vegetation and its dead parts provide a suitable shelter for individuals that have not burrowed themselves into the sediment. For both pulmonates and prosobranchs, finding a suitable microhabitat as a refuge is often crucial for their survival in harsh environmental conditions, including the periodic fluctuations of water level (Lajtner et al 2022), which is particularly important if the period of desiccation is long. Although we have not recorded any freshwater gastropods in the Krčić River, a previous study by Dorić (2016) reported Galba truncatula (O. F. Müller, 1774), A. fluviatilis and Gyraulus sp.…”

Benthic Macro-invertebrate Community Diversity of Orhuwhorun River in Udu Wetlands.

“…A study conducted by Spyra (2017) showed that a more diverse gastropod fauna was found in neutral ponds, whereas the lowest degree of diversity was found in ponds with the lowest pH. Gastropods were more downstream due to favorable conditions such as the presence of leaf litter which serve as food for them and extensive canopy cover provided by the trees and mangrove vegetation against predators (Lajtner et al 2022). Economically important gastropod species such as Tympanotonus sp.…”

Drivers for the Diversity of Mollusc Communities in Unique Calcareous Fen Habitats

“…Pulmonate gastropods can achieve a net uptake of the dissolved organic carbon (DOC) produced by macrophytes and metabolise it [31]. The important role of submerged macrophytes as a rich food source for gastropods and safe shelter from predators in shallow waterbodies was also confirmed by [32]. The increase in water temperature can result in higher periphyton biomass and in turn, higher biomass and density of gastropods in fish-absent ecosystems.…”