Freshwater Gastropod Diversity Research Articles

Freshwater Gastropod Diversity in The Selected Lotic Environment, Betong, Sarawak, Borneo

Freshwater Gastropoda can be considered as the biological indicator in ecosystems such as rivers, streams, lakes, and ponds. The objectives of this study are to identify freshwater gastropod species, diversity, and distribution along Sungai Penebak, Sungai Nanga Tiga, and Sungai Kabo in the Betong division. The study was conducted on 10 November 2020. A 50 m transect was laid on the riverbank of all three stations. The existing specimens were counted and collected from each sampling point and stored were taken to the laboratory for species identification. The diversity index and morphological study of freshwater gastropods were performed. Five species of freshwater gastropods belonging to four families were discovered. The five species of freshwater gastropods consisted of Sulcospira pageli, which shows great abundance, followed by Clea nigricans, Brotia costula, Pila ampullacea, and Vittina pennata. The diversity indices of collected Gastropoda species from the different stations, for instance, Shannon-Weiner diversity index (H’), Pielou’s evenness index (J’), and Margalef’s richness index were assessed; where station 3 showed higher diversity of Gastropoda compared to other two stations. The information presented in this paper might be helpful for ecological wealth studies and considered as the baseline data for the stream ecosystem in Sarawak, Malaysia.

Towards a Sustainable World: Diversity of Freshwater Gastropods in Relation to Environmental Factors—A Case in the Konya Closed Basin, Türkiye

The Konya Closed Basin (KCB) in Türkiye plays a key role in agricultural production and freshwater supply. However, the basin is impacted by humanly derived nitrogenous compounds and toxic metals. Keeping the water quality at a potable level in the basin is compulsory. This study was part of a project yielding monitoring of water quality in KCB in accordance with the Water Framework Directive (2000/60/EC). Eleven stations, except Beyşehir Lake and Mamasın Dam, were sampled for the first time for freshwater molluscs. Community structure indexes and multivariate statistical analyses were applied to determine the microhabitats of gastropods and their responses to environmental changes. The structure and distribution of gastropod assemblages differed depending on total phosphate, total nitrogen, dissolved oxygen, and pH. This study revealed that most of the gastropods in KCB are relatively tolerant to biodegradable pollution. However, there is a strong observed decline in population size requiring intensive future monitoring; measures have to be taken to preserve the remaining populations. Two endemic species need an urgent action plan to protect their habitats: Theodoxus anatolicus of Çeltik Canal and Bithynia pseudemmericia of Beyşehir Lake; a re-assessment of their extinction risk according to the IUCN rules is needed (2022). The results of this study will be useful for comparison with future studies to document potential improvements or continued ecological regression in the quality of aquatic ecosystems in the watershed.

Ecological index of freshwater gastropods in Kolaka District, Southeast Sulawesi, Indonesia

Abstract. Salwiyah, Purnama MF, Syukur. 2022. Ecological index of freshwater gastropods in Kolaka District, Southeast Sulawesi, Indonesia. Biodiversitas 23: 3031-3041. Kolaka District is one of the existing centers of high freshwater gastropod diversity in Southeast Sulawesi Province, Indonesia. more than 30 species of inland gastropods occupy this area and some of them (species) are used by local communities as food (daily consumption). This research was conducted for 4 months, namely January-April 2021 in Kolaka District, Southeast Sulawesi, Indonesia. The purpose of this study was to determine the ecological index (abundance, diversity, evenness, species richness, dominance, and distribution pattern) of the inland gastropod community in Kolaka. The sampling location of gastropods was determined qualitatively using the purposive sampling method and sampling using a simple random sampling technique (Quantitative based). Gastropod samples were collected manually (hand picking) using a paralone pipe (3.5 inches), Sieve (1 mm), and Gloves. The total gastropod sample obtained during the study was 1929 individuals consisting of 9 families, 19 genera, and 33 species. The average abundance of the gastropod population reached 96.45 ind./m2 and the abundance of gastropod species ranged from 0.75-15.05 ind./m2. Overall, the results of the gastropod ecological index analysis showed a stable condition, where the diversity of gastropod species was categorized as high (H': 3.20), moderate evenness (E: 0.90), and high species richness (R: 4.23), dominant dominance. showed that there were no dominant species (C: 0.1) and the distribution of gastropods showed a clumped pattern (Ip: 0.01). Empirically the ecological index data is a scientific justification related to the sustainability of inland water ecosystems or a description of the current freshwater homeostasis system in Kolaka.

Key Determinants of Freshwater Gastropod Diversity and Distribution: The Implications for Conservation and Management

Freshwater organisms are facing threats from various natural and anthropogenic disturbances. Using data sampled on a nationwide scale from streams in South Korea, we identified the crucial environmental factors influencing the distribution and abundance of freshwater gastropods. We used nonmetric multidimensional scaling and the random forest model to evaluate the relationships between environmental factors and gastropod assemblages. Among the 30 recorded species, two invasive gastropod species (Pomacea canaliculata and Physa acuta) have enlarged their distribution (10.4% and 57.3% frequency of occurrence, respectively), and were found to be widespread in streams and rivers. Our results revealed that the most influential factor in the distribution of gastropod assemblages was the ratio of cobble (%) in the substrate composition, although meteorological and physiographical factors were also important. However, the main environmental factors influencing species distribution varied among species according to habitat preference and environmental tolerance. Additionally, anthropogenic disturbance caused a decrease in the distribution of endemic species and an increase in the spatial distribution of invasive species. Finally, the results of the present study provide baseline information for planning successful strategies to maintain and conserve gastropod diversity when facing anthropogenic disturbance, as well as understanding the factors associated with the establishment of invasive species.

Improving estimates of richness, habitat associations, and assemblage characteristics of freshwater gastropods

Abstract Freshwater gastropods are imperilled globally and are among North America's most vulnerable major animal groups. Habitat loss, invasive species, and inadequate information about species distributions and assemblages all impair efforts to conserve freshwater gastropods. Conservation efforts are also impaired by difficulty obtaining and using distributional data for snails and other inconspicuous organisms, which are required to assess habitat associations. A gastropod‐specific sampling protocol was developed and used to survey 110 sites from 24 sub‐basins in two major river basins of the Intermountain West, USA. Habitat associations of individual taxa and groups of taxa that co‐occurred together more frequently than expected by chance were also examined. Using the gastropod‐specific sampling protocol, snails were found at most sites, even in regions where general macroinvertebrate sampling did not detect snails. Thus, these results show that general macroinvertebrate surveys do not accurately reflect the diversity of freshwater gastropods. Although snails of the same family are typically expected to live in the same habitats, this study found that in most cases, within a gastropod family, taxa exhibited unique habitat associations because they co‐occurred more frequently with taxa from different gastropod families. Five genera or sub‐genera were associated with specific mesohabitat or substrate types while two groups of co‐occurring taxa were associated with specific land classes or landform types. For diverse, inconspicuous taxa such as freshwater gastropods, qualitative, class‐specific sampling methods, and analyses of habitat associations based on co‐occurring taxa, rather than relatedness, should facilitate conservation efforts.

A Review of Species Diversity, Distribution and Ecology of Freshwater Gastropod Molluscs Inhabiting the Ukrainian Transcarpathian

Abstract The diversity of freshwater gastropods recorded in the Transcarpathian Region of Ukraine is reviewed and comments on their distribution and ecology are provided. Thirty-five species were revealed in samples collected from the lowland and mountainous parts of the Ukrainian Transcarpathia. Three species are recorded for the first time in the regional fauna: Viviparus sphaeridius, Bithynia troschelii and Segmentina montgazoniana. For species found in the region brief remarks on the biotopes in which they were registered and relevant taxonomic comments are given. The most distinctive features of the mollusc fauna of Ukrainian Transcarpathia are considered; the presence as well as the absence of some taxa in comparison with adjacent regions is discussed. The results of our observations confirm that the distribution of gastropod species depends on the types of waterbodies and their altitude location. The presented data contribute to the knowledge of the regional malacofauna and should help to assess the biogeographic status of the Transcarpathian Region more clearly.

Comparative morpho-anatomy and mitochondrial phylogeny of Semisulcospiridae in Yunnan, south-western China, with description of four new species (Gastropoda : Cerithioidea)

The taxonomic history of Chinese semisulcospirids is confusing. Originally placed in Melania by late 19th century authors, species have subsequently been dispersed into four different genera, i.e. Semisulcospira Böttger, 1886, Senckenbergia Yen, 1939, Hua Chen, 1943, and Namrutua Abbott, 1948; however, these placements were not conducted within a phylogenetic context. Based on examination of newly collected samples from the Chinese provinces Yunnan, Guizhou, Jiangxi, Anhui and Chongqing, we revised the systematics of the Chinese Semisulcospiridae based on comparative anatomy and mitochondrial phylogenetics. We have examined shell, radular, and reproductive features and employed Bayesian and Maximum Likelihood analyses of partial sequences of mitochondrial genes cytochrome c oxidase I and 16S rRNA to resolve the phylogenetic relationships. The results revealed that Semisulcospiridae is represented by three genera in China, which differ in their reproductive strategy, including Semisulcospira, which is viviparous and contains three species (S. ningpoensis, S. gredleri, and S. pleuroceroides); Hua, which is oviparous and contains 11 species; and Koreoleptoxis, which is oviparous and contains one species. Namrutua and Senckenbergia are identified here as junior subjective synonyms of Semisulcospira. All taxa recognised herein formed well differentiated clades in three mitochondrial phylogeny, and could be reliably distinguished by differences in shell shape and sculpture. Four new species of Hua are described from Yunnan Province. This is the first comprehensive study to review the taxonomy of semisulcospirids in China. These species are sensitive to water quality, and economic development and infrastructure expansion have negatively impacted many populations. We fear that some species may have disappeared before being investigated or described scientifically. Therefore, this research will hopefully inspire further studies and surveys to foster our understanding of freshwater gastropod diversity in China. http://zoobank.org/urn:lsid:zoobank.org:pub:EF2147FD-9EEE-4922-90DC-76651EF9E6AE

The impact of environmental factors on benthos communities and freshwater gastropod diversity in urban sinkhole ponds in roadside and forest contexts

Sinkhole ponds originated as a result of human activity leading to ground subsidence and create important habitats for the diversity of benthos fauna in urban areas. The objectives of this study were to determine whether the context (roadside/forest) is important in relation to the composition and diversity of macroinvertebrates, and to evaluate the influence of environmental factors (e.g. water quality) on snail communities. The study showed that the context of ponds had an impact on the properties of the water. Ponds located along roads were characterised by higher conductivity and a higher concentration of calcium and phosphates. The fauna was composed of 47 taxa, including 26 taxa found in both pond contexts. The density of macroinvertebrates was higher in forest ponds. CCA analysis showed that conductivity and concentration of nitrates were most strongly associated with the distribution of gastropods. Alien snail species more often inhabited the roadside ponds.

A preliminary checklist of the freshwater snails of Sabah (Malaysian Borneo) deposited in the BORNEENSIS collection, Universiti Malaysia Sabah.

Sabah, a Malaysian state at the north-eastern tip of Borneo, is situated in one of the Earth’s biodiversity hotspots yet its freshwater gastropod diversity remains poorly known. An annotated checklist of the freshwater gastropods is presented, based on specimens deposited in the BORNEENSIS collection of the Institute for Tropical Biology and Conservation at Universiti Malaysia Sabah, Malaysia. A KMZ file is also provided, which acts as a repository of digital images and complete collection data of all examined material, so that it can be shared and adapted to facilitate future research.

Freshwater gastropods diversity hotspots: three new species from the Uruguay River (South America).

Background: The Atlantic Forest is globally one of the priority ecoregions for biodiversity conservation. In Argentina, it is represented by the Paranense Forest, which covers a vast area of Misiones Province between the Paraná and Uruguay rivers. The Uruguay River is a global hotspot of freshwater gastropod diversity, here mainly represented by Tateidae (genus Potamolithus) and to a lesser extent Chilinidae. The family Chilinidae (Gastropoda, Hygrophila) includes 21 species currently recorded in Argentina, and three species in the Uruguay River. The species of Chilinidae occur in quite different types of habitats, but generally in clean oxygenated water recording variable temperature ranges. Highly oxygenated freshwater environments (waterfalls and rapids) are the most vulnerable continental environments. We provide here novel information on three new species of Chilinidae from environments containing waterfalls and rapids in the Uruguay River malacological province of Argentina.Materials and Methods: The specimens were collected in 2010. We analyzed shell, radula, and nervous and reproductive systems, and determined the molecular genetics. The genetic distance was calculated for two mitochondrial markers (cytochrome c oxidase subunit I–COI- and cytochrome b -Cyt b-) for these three new species and the species recorded from the Misionerean, Uruguay River and Lower Paraná-Río de la Plata malacological provinces. In addition, the COI data were analyzed phylogenetically by the neighbor-joining and Bayesian inference techniques.Results: The species described here are different in terms of shell, radula and nervous and reproductive systems, mostly based on the sculpture of the penis sheath. Phylogenetic analyses grouped the three new species with those present in the Lower Paraná-Río de la Plata and Uruguay River malacological provinces.Discussion: Phylogenetic analyses confirm the separation between the Uruguay River and the Misionerean malacological provinces in northeast Argentina. These new endemic species from the Uruguay River add further support to the suggestion that this river is a diversity hotspot of freshwater gastropods (with 54 species present in this basin, 15 of them endemic). These endemic species from environments with rapids and waterfalls should be taken into account by government agencies before the construction of dams that modify those ecologic niches in the Uruguay River.

Gastropod diversity, distribution and abundance in habitats with and without anthropogenic disturbances in Lake Victoria, Kenya

We investigated freshwater gastropod diversity, abundance and distribution in habitats with and without anthropogenic disturbance in two localities, Ndere in the Winam Gulf and Mbita Point, Lake Victoria, Kenya, from May 2002 to January 2004. A total of 133 984 gastropod specimens belonging to 15 species were recorded, 14 from Mbita and 12 from Ndere. Two species, Ferrissia kavirondica and Cleopatra cridlandi, which were recorded only from undisturbed habitats, could be indicators of least disturbed habitats. Water chemistry did differ between fish landing sites and undisturbed habitats at some sampling times, indicating that differences due to human impact do exist, but these are dependent on periods of calm weather. The study shows that anthropogenic disturbances cause ecological changes that can be exploited by some snail species, especially Biomphalaria choanomphala and Melanoides tuberculata, while other species may not tolerate these changes. In order to protect gastropod diversity and avoid dominance of intermediate hosts, such as B. choanomphala, a management plan for the use of these fish landing sites should be developed. This could include rules on how to dispose of fish remnants and other wastes so as to reduce local eutrophication, thereby reducing risks associated with transmission of potential snail-borne diseases.

Latitudinal changes in the diversity of freshwater gastropods (Mollusca: Gastropoda) in waterbodies of western Siberia

The patterns of spatial variation in gastropod diversity in the waterbodies of western Siberia have been revealed. The highest species and generic diversity of freshwater gastropods is found in the waterbodies of the forest-steppe zone; from there, these parameters significantly decrease northwards, reaching their minimum beyond the polar circle. The proportion of gastropods of non-European origin increases in the same direction. The possible reasons for these changes in the spatial diversity of aquatic gastropods and the likely connections between the latitudinal variation of their diversity and the geological history and features of the relief of western Siberia are discussed. It is assumed that the forest-steppe zone of western Siberia is a local center of aquatic gastropod diversity.

Winning the biodiversity arms race among freshwater gastropods: competition and coexistence through shell variability and predator avoidance

Explanations for the coexistence of many closely related species in inland waters continue to be generated more than 50 years after Hutchinson’s question: why are there so many kinds of animals? This review focuses on the hypothesis that high species diversity of freshwater gastropods results, in part, from predators maintaining biodiversity across a range of deep- and shallow-water habitats. Invertebrate predators, such as aquatic insects, and leeches consume soft tissue of pulmonate snails by penetrating shells of various shapes and sizes. Crayfish and large prawns chip around the shell aperture to enter thick shells and crush small shells with their mandibles. Crabs use their strong chelae to crush thin and thick shells. Fishes with pharyngeal teeth are major shell-breaking predators that combine with other vertebrate predators such as turtles and wading birds to increase the diversity of gastropod communities by regulating the abundance of dominant species. Although the generalized diets of most freshwater predators preclude tight co-evolutionary patterns of responses, there are combinations of predators that modify gastropod behavior and shell morphology in aquatic assemblages of different ages and depths. This combination of invertebrate and vertebrate predatory impacts led to competitive advantages among individual gastropods with different adaptations: (1) less vulnerable shell morphologies and sizes; (2) predator-avoidance behaviors; or (3) rapid and widespread dispersal with variable life histories. Some individuals develop thicker and/or narrow-opening shells or shells with spines and ridges. Other thin-shelled species crawl out of the water or burrow to lower their risk to shell-breaking or shell-entering predators. Some alter their age at first reproduction and grow rapidly into a size refuge. Fluctuations in water levels and introductions of non-native species can change competitive dominance relationships among gastropods and result in major losses of native species. Many different gastropod predators control species that are human disease vectors. Most snails and their predators provide other ecosystem services such as nutrient cycling and transfer of energy to higher trophic levels. Their persistence and diversity of native species require adaptive management and coordinated study.

Distribution and Environmental Influences on Freshwater Gastropods from Lotic Systems and Springs in Pennsylvania, USA, with Conservation Recommendations

We examined current distributions of and influential variables on aquatic gastropods in streams and springs across the state. Our research located 37 species representing 7 families. This inventory included rare species such as Somatogyrus pennsylvanicus Walker, 1904 and several populations of the Ohio Pebblesnail Somatogyrus integra (Say, 1829). Despite targeted surveys, no collections were made of the Buffalo Pebblesnail Gillia altilis (I. Lea, 1841). We also examined the influence of rapid bio-assessment habitat measurements, reach and basin hydrological variables, and selected water chemistry variables on the freshwater snail communities of Pennsylvania. Several measures of habitat quality, drainage area, and water chemistry were among the more important variables explaining patterns in species richness. Several species appear rare and 7 species are recommended for conservation consideration. Further work is needed to better understand the diversity of freshwater gastropods in Pennsylvania.