Gastropod Species Diversity Research Articles

Biodiversity and distribution of gastropods at seagrass meadow of Balangdatu waters Tanakeke Island South Sulawesi Indonesia

The research about the biodiversity of gastropod has been conducted in seagrass meadow of Balangdatu waters, Tanakeke Island, South Sulawesi. The research aims to assess the diversity of gastropod species in Balangdatu waters. Sampling was conducted using quadrate transect method systematically. Three replicates of transect were applied for each station. The result indicates there were 34 species of gastropods from 14 genera and 14 families were found. Diversity index from every station varies from 1,661 to 2, 899. These values range from low to moderate. The diversity, Evenness, and dominance indices showed that Balangdatu waters still in good condition and sustain habitat for gastropod.

Marine island biogeography. Response to comment on ‘Island biogeography: patterns of marine shallow‐water organisms’

AbstractIn this response we have incorporated data on gastropod and seaweed biodiversity referred to by Ávila et al. (2016, Journal of Biogeography, doi:10.1111/jbi.12816) to allow an updated analysis on marine shallow‐water biogeography patterns. When compared to the biogeography patterns reported in Hachich et al. (2015, Journal of Biogeography, 42, 1871–1882), we find (1) no differences in the patterns originally reported for reef fish or seaweeds, (2) minor differences in gastropod species–area and species–age patterns and (3) a significant difference for the gastropod species‐isolation pattern. In our original work, we reported that there was limited evidence that gastropod species richness was influenced by island isolation; however, our new analysis reveals a power‐model relationship between these variables. Thus, we are now able to conclude that gastropod species diversity, whose dispersal capacity is intermediate between seaweeds (lowest) and reef fish (highest), is also influenced by island isolation.

KEANEKARAGAMAN GASTROPODA PADA ZONA INTERTIDAL TENGAH (MIDLE INTERTIDAL ZONE) DAN ZONA INTERTIDAL BAWAH (LOWER INTERTIDAL ZONE) DAERAH PADANG LAMUN DESA WAAI

Background: Seagrass grows and spreads in nearly all parts of the intertidal zone. Waai village has characteristic sloping coastal water and have different patterns of zonation of seagrass in the intertidal zone's third-impact on the presence of seagrass and the organisms in it.
 Methods: The study was conducted in coastal waters Waai village, in the middle of the intertidal zone (middle intertidal zone) and the lower intertidal zone (lower zone intertidal). The samples in this study are all kinds of gastropods found in each plot observation station of 100 plots. Gastropod species diversity using diversity index formula Shannon - Wiener referred to under Ludwig and Reynolds.
 Results: From the results of the study found 8 species of gastropods and has a diversity index that is currently in the middle intertidal zone, the average diversity index of 1.76, while in the lower intertidal zone, the average gastropod diversity index was 1.45.
 Conclusion: diversity index indicates the middle intertidal zone, the average diversity index of 1.76, while in the lower intertidal zone, the average index of diversity of gastropods is 1.45, this is caused by the different seagrass zonation patterns and habits of the people who frequently uses seagrass area for commercial purposes.

Quality or quantity: small-scale patch structure affects patterns of biodiversity in a sublittoral blue mussel community

It is widely accepted that blue mussel Mytilus edulis L. beds support a high macrofaunal diversity. Nonetheless, sublittoral mussel beds on rocky shores have rarely been examined in a patch context to determine the processes creating and maintaining the diversity and assemblages of organ- isms occupying them. Whereas the species-area relationship is a well-established theory in ecology, less is known about its effect on faunal compositions in aquatic habitats. Also, the effect of patch shape and relative patch edge are poorly studied within a rocky shore mussel framework. The pre- sent study examined the effects of blue mussel patch size, patch shape, and the presence of algae and sand in mussel patches on the composition and diversity of associated macrofaunal communities in sublittoral habitats. In line with the species-area relationship, we found that the total number of taxa increased with patch size up to ca. 500 cm 2 , thereafter declining. Small patches largely lacked annelid worms and showed a lower diversity of gastropod species. We also found that the diversity was further enhanced by a high biomass of blue mussels, the presence of algae and the weight of interstitial sand. The shape of the patch had no effect on species richness, but affected the species composition. We conclude that structural components of sublittoral blue mussel habitats, such as patch content and shape, greatly affect the diversity and faunal assemblage. This has important impli- cations in conservation biology, since habitats are becoming more fragmented. Our study demon- strates that not only habitat quantity, but also quality has a large impact on species communities in marine ecosystems.

Taphonomy and palaeoecology of the gastropod fauna from a Late Cretaceous rocky shore, Sweden

A gastropod fauna comprising 17 species, each represented by a limited number of specimens, is described from a Late Cretaceous, late early Campanian rocky shore at Ivö Klack, southern Sweden. The gastropod fauna is associated with the most diverse ancient rocky shore fauna ever found. However, the low gastropod species diversity compared to the faunas of modern rocky shores is ascribed to taphonomic factors, notably dissolution of the aragonitic shells, but the predominance of epifaunal herbivores is indicative of a guild structure similar to that found on modern rocky shores. The presence of drill holes assigned to the ichnospecies Oichnus simplex suggests the former presence of muricid gastropods which have not been found as body fossils. A single drill hole is referred to Oichnus paraboloides and was probably made by a naticid gastropod. The infaunal mode of life of naticids makes preservation of such drill holes difficult, since the majority of infaunal prey such as burrowing bivalves has aragonitic shells which are not preserved. The relatively high number of species in comparison to many other Late Cretaceous rocky shore faunas, offers an opportunity to compare gastropod guild structure at Ivö Klack with modern counterparts, even though taphonomic processes such as mechanical destruction and aragonite dissolution have played an important role in the fossil gastropod assemblage.

Bathymetric patterns of deep‐sea gastropod species diversity in 10 basins of the Atlantic Ocean and Norwegian Sea

AbstractBathymetric patterns of macrofaunal species diversity are best documented in the western North Atlantic where diversity is a unimodal function of depth, peaking in the mid‐bathyal zone and being depressed in the upper slope and abyss. There are few inter‐basin studies of diversity‐depth trends that are controlled for taxonomy, sampling gear, and diversity measures. In this paper, we compare gastropod diversity gradients in the North American Basin of the Atlantic to estimates of diversity in 9 other regions: the Norwegian Sea, West European Basin, Guiana Basin, Gambia Basin, Equatorial Mid‐Atlantic, Brazil Basin, Angola Basin, Cape Basin and Argentine Basin. All samples were collected with epibenthic sleds, and diversity calculated by the Sanders‐Hurlbert normalized expected number of species. While sampling in other regions is generally less complete than in the western North Atlantic, results indicate that a unimodal pattern is not universal. Diversity can increase, decrease or show no relationship with depth. The level of diversity also varies among basins relative to the western North Atlantic, being depressed in the Norwegian Sea, at bathyal depths in the eastern North Atlantic, and below an oxygen minimum zone in the Cape Basin, and generally elevated at tropical latitudes and in abyssal regions where food supply is high. Associations between gastropod diversity and the ecology and geology of basins suggest that productivity, oxygen concentration, hydrographic disturbance and evolutionary‐historical processes may be implicated in shaping bathymetric diversity gradients, but specific causes are difficult to discern. Much more intensive sampling, analyses of other major taxa, and more detailed ecological data are necessary to understand deep‐sea biogeography at within‐ and between‐basin spatial scales.

Response of snails and slugs to fragmentation of lowland forests in NW Germany

Habitat fragmentation is a major cause for species loss, but its effect on invertebrates with low active dispersal power, like terrestrial gastropods, has rarely been studied. Such species can not cross a hostile habitat matrix, for which the predictions of island theory, such as positive relations between species richness and patch size, should apply. In order to test this prediction, we studied gastropod species diversity by assessing gastropod assemblage characteristics from 35 sites in 19 fragments of deciduous old-growth forests in the Lower Rhine Embayment, Germany. Assemblages differed between larger (≥700 ha) and smaller forests ( 1,000 ha, i.e., well above the size of most fragments. In conclusion, the prediction is valid only for forest species. The response to fragmentation is species specific and seems to depend on habitat specialization and macroclimatic conditions.

Comparison of a sediment trap and plankton pump for time‐series sampling of larvae near deep‐sea hydrothermal vents

Studies of larval dispersal and supply are critical to understanding benthic population and community dynamics. A major limitation to these studies in the deep sea has been the restriction of larval sampling to infrequent research cruises. In this study, we investigated the utility of a sediment trap for autonomous, time‐series sampling of larvae near deep‐sea hydrothermal vents. We conducted simultaneous deployments of a time‐series sediment trap and a large‐volume plankton pump in close proximity on the East Pacific Rise (2510‐m depth). Grouped and species‐specific downward fluxes of larvae into the sediment trap were not correlated to larval abundances in pump samples, mean horizontal flow speeds, or mean horizontal larval fluxes. The sediment trap collected a higher ratio of gastropod to polychaete larvae, a lower diversity of gastropod species, and over‐ or undercollected some gastropod species relative to frequencies in pump sampling. These differences between the two sampling methods indicate that larval concentrations in the plankton are not well predicted by fluxes of larvae into the sediment trap. Future studies of deep‐sea larvae should choose a sampling device based on specific research goals. Limited by battery power, a plankton pump in combination with a current meter is useful for estimating horizontal advective fluxes in short‐term (days to weeks) studies of larval dispersal. A sediment trap, selecting for larvae with downward trajectories, is more appropriate for studies of larval supply to the benthos. For some species, a time‐series sediment trap can collect sequential larval samples for long‐term studies (months to years) for correlation to larval settlement and recruitment patterns.

FINE-SCALE HABITAT ASSOCIATIONS OF SOFT-SEDIMENT GASTROPODS AT CAPE MACLEAR, LAKE MALAWI

Lake Malawi harbours a high diversity of gastropod species, yet little is known of their distributions or habitat affiliations. We conducted a study of the gastropods present on soft sediments at five sites around Cape Maclear, in the south of the lake. The two most common taxa were Bulinus nyassanus, a known vector for Schistosoma haematobium and Melanoides. Both were found to be in much higher abundance than ever previously recorded. Densities of these gastropods were highly dependent upon habitat characteristics including depth, sediment particle size and sediment organic content. Together these factors explained 49 and 70% of variance in B. nyassanus and Melanoides abundance, respectively. There were no significant differences between the five sites after accounting for habitat variables. These data indicate that habitat characteristics are substantially important in determining the geographic differences in gastropod abundance, thus we propose that nearshore habitat variables may be strongly linked to schistosomiasis prevalence among lakeshore human populations.

Ecology of tropical hermit crabs at Quirimba Island, Mozambique:shell characteristics and utilisation

The use of gastropod shells by hermit crabs at Quirimba Island, Mozambique, was investigated. Particular attention was paid to the upper shore/supralittoral zone species Clibanarius longitarsus, Coenobita cavipes and Coenobita rugosus. The study area is characterised by a high diversity of gastropod species as well as hermit crabs. Supralittoral hermit crabs were little, if at all, resource restricted due to concentration of empty shells on the strandline and shell middens created by local people. The range of the 3 study species overlaps substantially and each uses a wide range of shell types. Shore habitat, shell abundance and availability were found to have little influence on shell use. With increased tidal emersion/terrestrial nature (for a given crab mass), total diversity of shells used increased, shell mass carried decreased, damaged shell use decreased and carried shell fit increased. The architecture and strength of shells used, however, followed more complex individual species characteristics and behaviour patterns. Species specific differences in behavioural patterns may be important for shell resource partitioning.

Deep-Sea Species Diversity: Decreased Gastropod Diversity at Abyssal Depths

Gastropod species diversity is low on the continental shelf, high on the continental slope and abyssal rise, and then decreases with increasing distance out onto the abyssal plain. Increased diversity below the continental shelf has been attributed to increased environmental stability. Decreased diversity on the abyss may result from extremely low productivity.