Mollusc Communities Research Articles

Correction: Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

Correction: Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

Vodní měkkýši lomů ČSA a Vršany – počátek kolonizace [Aquatic molluscs of the quarries ČSA and Vršany – the beginning of colonization

In 2022 and 2023, aquatic molluscs were surveyed in brown coal quarries ČSA and Vršany, northwestern Bohemia, where mining is ending and reclamation is in progress. Most water bodies were artificially created and relatively young, though some older habitats were present at the quarry edges. In the quarry ČSA, 20 species (17 gastropods, 3 bivalves) were recorded at 40 sites, while 13 species (10 gastropods, 3 bivalves) were found at 39 sites in Vršany. Molluscan communities were generally species-poor, particularly in deeper waters without shallows or with dense reed growth. Shallow, vegetated areas were more favorable. Physa acuta was the most frequent species. Three non-native species (Physa acuta, Potamopyrgus antipodarum, Ferrissia californica) were confirmed, and no protected or endangered species were found.

Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

Hubungan komunitas moluska dengan parameter lingkungan di kawasan mangrove Pulau Penyu, Tanjung Benoa, Bali

Mangroves are plants in coastal and estuary areas that are influenced by tides. Mangroves provide essential habitats as spawning, nursery and food sources for various biota, including mollusks. Mollusks have a reciprocal relationship with mangrove plants, play an important role in maintaining the balance of the food chain in mangrove ecosystems. The objective of the research is to establish the structure of the mollusk community and its correlation with environmental conditions in the Pulau Penyu mangroves. The study was carried out in September 2023. The method employed the 1x1m quadrat transect with 15 points per station. Salinity, pH, temperature and substrate type are all measurements of environmental conditions. The research revealed 24 species, including 20 gastropod species and 4 bivalvia species from 12 mollusk families. Families found include Potamididae, Cerithiidae, Batillariidae, Ellobiidae, Mitridae, Neritidae, Littorinidae, Naticidae, Muricidae, Veneridae, Cyrenidae and Corbulidae. Mollusk abundance ranged from 0,07 to 13,07 ind/m2 at the research site, with Cerithium coralium being the most abundant species and Corbula macgillivrayi being the least abundant. The results of diversity index is 1,90 to 2,25; evenness index is 0,68 to 0,78; dominance index is 0,18 to 0,25; indicating moderate species diversity, high individual numbers each species, and no dominant species. The range of environmental parameter values obtained were; temperature ranges from 34,1 to 35,37 oC; pH ranges from 6,43 to 6,68; and salinity ranges from 35,2 to 36,3 ppt. The substrate type at the research site was sandy clay and clayey sand. PCA analysis results indicate a strong relationship between mollusk abundance and pH, salinity and sand fraction, but very weak relationship with temperature, dust and clay fraction.

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

The research was carried out in calcareous fen habitats which share coverage with Natura 2000 sites designated under the EU Habitats and the Birds Directive. A total of 27 taxa of molluscs were recorded: 23 gastropod and 4 bivalve species. Anisus vorticulus, one of the species of Community interest whose conservation requires designation of special conservation areas within the Habitats Directive Natura 2000, was subrecedent and accedent in mollusc communities. Calcareous fen habitats offer the aquatic organisms harsh environmental conditions including a relatively high temperature of the water up to 33.29 °C (undrained fens), oxygen deficits in the water, high pH of up to 11.08 (fen pools) and conductivity above 3000 μS cm−1 (fen ditches). Therefore molluscs have to face extreme environmental conditions. Temperature of the water, pH, dissolved oxygen and conductivity were the parameters most associated with the distribution of mollusc species in the calcareous fen habitats. The abundance of submerged and floating macrophytes, the degree of habitat persistence and the fish predation pressure on molluscs also exerted a significant effect on their distribution. The calcareous fen habitats that are listed in Annex I of the European Union Habitats Directive create a unique valuable ecosystem that contributes to the natural diversity of aquatic organisms.

The response of epibenthic molluscan assemblages associated with Mytilus galloprovincialis beds to natural- and human-induced changes: Structure and small-scale spatiotemporal variability

Mussel beds are species-rich and diversified biogenic habitats for associated assemblages, playing important ecological roles and contributing significantly to local littoral invertebrate biodiversity. The community structure and seasonal patterns of molluscan assemblages associated with rocky-intertidal mussel Mytilus galloprovincialis beds along NW Atlantic coast of Morocco were investigated. Sampling was conducted at reference and contaminated stations in three distant coastal areas over a 4-season sampling period (between August 2018 and May 2019). We tested the hypothesis that the biogenic mussel habitats in areas experiencing different environmental conditions along the shore would support different associated molluscan assemblages under human-induced and natural changes at small spatial and temporal scales. A total of 6371 specimens comprising 28 taxa were identified and encompassing four trophic groups (carnivores, detritivores/deposivores, micrograzers and suspensivores). Micrograzers predominated, followed by carnivores, with gastropods being the numerically dominant taxa accounting for 79 % of total abundance. Steromphala pennanti emerged as the most abundant and frequent species, across almost all seasons and stations contributing to 31 % of total abundance. Significant seasonal variations were observed in species richness and Shannon-Wiener’s index (ANOVA, p<0.05), with the highest values recorded at the most polluted stations during cold/wet periods, and the lowest at the cleanest stations during hot/warm periods. Furthermore, the ANOVA analyses unveiled a significant spatiotemporal variation in abundance, emphasizing the dynamic nature of molluscan assemblages in response to environmental conditions and seasonal changes. The multivariate structure of associated molluscan assemblages (PERMANOVA analysis) differed significantly among stations and seasons, highlighting clear geographical and seasonal effects. Gastropod species, including Acanthochitona fascicularis, Lepidochitona cinerea, Nucella lapillus, Patella ulyssiponensis, P. vulgata, Phorcus lineatus, P. sauciatus, and Steromphala pennanti, were identified as the most contributive species to the dissimilarity of molluscan assemblage structure among stations throughout seasons (SIMPER analysis). Based on the canonical correspondence analysis results, salinity, water temperature, nutrient concentrations, sediment granulometry and total organic matter were identified as the key factors driving changes in the molluscan community structure. This study underscores the ecological importance of habitat-forming mussels as ecosystem engineers and biodiversity enhancers in shallow coastal waters along the Moroccan Atlantic coast.

Development of environmental DNA metabarcoding primers for marine mollusks and comparison with published primers

Monitoring mollusk biodiversity is a great challenge due to their large diversity and broad distribution. Environmental DNA (eDNA) technology is increasingly applied for biodiversity monitoring, but relevant studies on marine mollusks are still limited. Although previous studies have developed several pairs of primers for mollusk eDNA analyses, most of them targeted only a small group of mollusks. In this study, seven primers were designed for the mollusk community and validated and compared with eight pairs of published primers to select the best candidates. After in silico test, MollCOI154 and MollCOI255 primers showed non-specific amplification, and same results were also obtained in published primers (COI204, Sepi, and veneroida). Moll12S100, Moll12S195 and Moll16S primers failed to amplify across all genomic DNA from selected mollusk. Except Moll16S, all developed and two published (unionoida and veneroida) primers were successfully amplified on four eDNA samples from Yangtze River estuary. After annotation of the amplified sequences, MollCOI253 showed higher annotation of the amplification results than the other primers. In conclusion, MollCOI253 had better performance in terms of amplification success and specificity, and can provide technical support for eDNA-based research, which will be beneficial for molluscan biodiversity investigation and conservation.

Effects of different hydrological conditions on the taxonomic structure and functional traits of mollusk communities in a large floodplain wetland.

Floodplain wetlands are critical to the conservation of aquatic biodiversity and the ecological integrity of river networks. However, increasing drought severity and frequency caused by climate change can reduce floodplain wetlands' resistance and recovery capacities. Mollusks, which are common inhabitants of floodplain wetlands, are among the most vulnerable species to drought. However, the response of mollusk communities to drought has received little attention. Here, we investigated how the structure and functional traits of mollusk communities changed in response to varying hydrological conditions, including a flash drought (FD) in the Poyang Lake floodplain wetland. Our findings showed that FD strongly reduced mollusk abundance and biomass, decreased both α- and β-diversity, and resulted in the extinction of bivalve taxa. A sudden shift in community trait structure was discovered due to the extinction of many species. These traits, which include deposit feeding, crawling, scraping, aerial respiration, and dormancy, help mollusks survive in FD and tolerate completely dry out of their Changhuchi habitat. Finally, we discovered that dissolved oxygen was an important controlling variable for mollusk communities during drought. Our findings provide a scientific basis for the management and conservation of floodplain wetland biodiversity in the context of increasing drought frequency and intensity.

MOLLUSCAN DIVERSITY THE MANGROVE ECOSYSTEM OF TARAKAN ISLAND INDONESIA

Mangrove in Tarakan coast encounter various underlined threat named pollution, habitat destruction, and the swelling of human population impending the existence of Molluscan communities. Molluscan is an essential component of Mangrove ecosystem since it could be as predator, herbivore, detritivore, and biofilter as well. However, there only minimum study found investigate the impact of Mangrove. This study, which was conducted from March to August 2023 in five mangrove regions of Tarakan Island, uncovered the distribution of 54 molluscan species, of which 46 were gastropods and 8 were bivalves. This study has identified a remarkable number of species, among the greatest among mangrove ecosystems in Indonesia. Additionally, this study provides an initial account of the distribution of gastropods in the mangrove region of Tarakan Island. The region north of Tarakan Island known as the Juwata mangrove forest harbors the greatest variety of molluscan. A comprehensive documentation of the molluscan species diversity in the mangrove ecosystem adjacent to Tarakan Island's coast has been compiled in order to furnish conservation management with fundamental data that is practical and beneficial.

Hydrothermal and eco-environmental evolution on the southeastern Chinese Loess Plateau since the last deglaciation: evidence from terrestrial mollusk records

The ongoing global warming is altering hydrothermal patterns and eco-environments. However, it is unclear how they would respond under a natural warming scenario. Terrestrial mollusks in loess-paleosol sequences could serve as natural biological archives to explore this issue. In this study, terrestrial mollusk records from two loess-paleosol profiles on the southeastern Chinese Loess Plateau (CLP) were analyzed. Our results show that the cold-aridiphilous species decreased and the overall biodiversity increased gradually during the last deglaciation (∼19.0–11.5 ka BP), which was accompanied with the shift from cold-dry to warm-humid climate. Moreover, the mollusk communities reacted to Heinrich event 1 (H1) cooling. In the early-middle Holocene (∼11.5–5.5 ka BP), mollusk communities were dominated by the thermo-humidiphilous species, characterized by stable community composition, increased species richness and evenness with warm-humid climate. Thereafter, there was a noticeable decrease in species diversity and increase in the cold-aridiphilous species in the mid-late Holocene (∼5.5–0 ka BP), associated with a gradual shift towards a cold-dry climate. On the whole, it is noteworthy that the count of thermo-humidiphilous species increased remarkably at ∼16 ka BP, which is synchronous with a significant increase in the Northern Hemisphere summer insolation. Interestingly, this change of terrestrial mollusks preceded the formation of the Holocene paleosol at ∼8 ka as indicated by the pronounced increase in magnetic susceptibility and decrease of mean grain size. This suggests that the substantial East Asian summer monsoon (EASM) precipitation lagged the onset of deglacial warming on the southeastern CLP. Furthermore, this delay may be attributed to the negative feedback of North Atlantic meltwater, which caused a decline in the intensity of Atlantic Meridional Overturning Circulation (AMOC) and inhibited the rapid enhancement of EASM precipitation during the last deglaciation. Altogether, this provides crucial geological background evidence for exploring the potential regional hydrothermal and biodiversity responses to global warming in the near future.

Anthropogenic–induced environmental and ecological changes in the Nile Delta over the past half-century

Anthropogenic activities over the past half-century have had a negative impact on the wetland ecosystem in the Nile Delta, which provides essential provisioning and regulating services. Therefore, it is crucial to systematically investigate pollution levels and their ecological consequences at both spatial and temporal scales in order to promote sustainable development. In this study, data on metal pollution in the Manzala Lake were compiled through a systematic review of all published literature from 1968 to 2020. Additionally, agricultural data (including land use, pesticide and fertilizer usage, and discharge) and economic data for the same time period were collected to identify the main drivers of pollution. The results indicated an overall increasing trend in heavy metal concentrations during the study period. The average concentrations of metals, arranged in descending order, were as follows: Fe (15,115.5 μg/g) > Mn (722 μg/g) > Zn (115.4 μg/g) > Cu (65.9 μg/g) > Ni (62.5 μg/g) > Cr (58.1 μg/g) > Pb (54.1 μg/g) > Cd (4.7 μg/g) > Hg (0.1 μg/g). A linear regression model revealed that wastewater discharge, water reuse, and the use of pesticides and fertilizers are the main sources of heavy metal pollution in the Manzala Lake. Consequently, there has been a dramatic decrease in the biodiversity of fish and molluscan communities. The study also found a correlation between heavy metal pollution and socio-economic development, highlighting the urgent need for attention to the conservation, management, and sustainable development of the lake.

Biodiversity of intertidal mollusks in Surigao City, Philippines

Intertidal zones are crucial ecological interfaces, but there is a lack of comprehensive studies on mollusk communities in Surigao City, Philippines. This research aimed to assess intertidal mollusk profiles, including species density, diversity, evenness, and richness, addressing a knowledge gap in regional mollusk biodiversity. Using a belt transect quadrat method in three sampling areas during 2021, the study employed a descriptive correlation design to investigate relationships between mollusk profiles and seawater physico-chemical parameters (conductivity, dissolved oxygen, pH, salinity, and temperature). In Surigao City's Day-asan, Hikdop Island, and Sibale, 44 gastropod species (19 families) and 11 bivalve species (9 families) were identified. Conidae and Strombidae families dominated. Average seawater parameters were conductivity 51.33, dissolved oxygen 7.45, pH 7.84, salinity 32, and temperature 28.52. Day-asan exhibited the highest species count (49), followed by Hikdop Island (42) and Sibale Island (37). Hikdop Island had the highest species density and evenness, Day-asan had the highest species diversity index, and Sibale Island had the highest species richness. Mollusk profiles showed no significant differences between sampling areas, and a strong negative correlation between pH and species evenness was observed. Surigao City displayed diverse mollusk biodiversity, but a declining trend in diversity indices was noted. This study fills a critical knowledge gap in understanding mollusk community dynamics, providing essential baseline data for future conservation and management strategies in the region, while also shedding light on the impact of environmental factors on intertidal mollusk populations in Surigao City.

Recent and future distribution of the alien Chinese pond mussel Sinanodonta woodiana (Lea, 1834) on the European continent

The alien freshwater mussel Sinanodonta woodiana (Lea, 1834) has rapidly spread throughout Europe over the past decades. This species can cope with a broad range of environmental conditions and has a high reproductive capacity making S. woodiana a successful invader. Due to its negative effects on native freshwater mollusk communities and parasitized fish it is critical to identify suitable habitats where S. woodiana may persist and how these habitats may be altered under future climate projections. We applied multivariate ordination methods to analyze the space-time relationship and a maximum entropy approach (MaxEnt) to predict the recent (1970–2000) and future (2041–2060 and 2081–2100) distribution of S. woodiana using environmental and climate variables for the European continent. After first sightings in 1979 there were only a few new locations and findings which increased unevenly and exponentially to a maximum of about 100 new locations per year followed by decline during the last few years. Under recent climate condition, 2.3% of European watersheds are predicted as highly suitable habitat for S. woodiana and located in the temperate climate zone between 40°N and 60°N. Suitable habitat was associated with lowland watersheds characterized by fluviatile deposits and agriculture. Elevation, the distance between water bodies, land cover and mean temperature of the coldest quarter were the main factors influencing the modeling results. For future climate scenarios, highly suitable habitat increased to 2.4% by the middle of this century and decreased to 2.2% by the end of the century under the ‘least radiative forcing’ scenario. For the intermediate and high radiative forcing in 2050 and 2100, highly suitable habitat decreased to 2.2% and 1.7% and to 2.2% and 2.2%, respectively. Results from our study can be used as a baseline to better understand potential invasion pathways, identify high risk areas, and to initiate early detection and rapid response strategies.

Monospecific mangrove reforestation changes relationship between benthic mollusc diversity and biomass: Implication for coastal wetland management

Anthropogenic causes are overtaking natural factors to reshape patterns of biodiversity and ecosystem functioning. Mangrove reforestation aimed at reversing losses of mangroves has been conducted worldwide for several decades. However, how reforestation influences the link between ecological processes that shape community diversity and the consequent effects on ecosystem functions such as biomass production is less well known. Here we used data collected before and after mangrove planting to examine the effects of reforestation on molluscan species richness and biomass production by testing the changes in species richness, compositional similarities, distance-decay effects (community similarity decreases with increasing geographical distance) in metacommunity across a regional scale of 480 km (23–27 °N) in southeast Chinese coasts. Additionally, we further detected the impact of landscape configuration caused by different intensities of reforestation on the mollusc community. After the mangrove reforestation, mollusc species richness and biomass increased significantly. The increases in species richness and biomass of mollusc community were mediated by reducing distance-decay effect, indicating an increase in relationship strength between species richness and biomass might be associated with a decrease in distance-decay effect with rising mangrove habitat. We highlight the importance of considering the effects of anthropogenic changes on the relationship between biodiversity and ecosystem functioning. Quantifying the distance-decay effect of these influences enables management decisions about coastal restoration to be based upon ecological mechanisms rather than wishful thinking or superficial appearance.

Vodní měkkýši Odlezelského jezera [Aquatic molluscs of Lake Odlezly

The Odlezelské jezero National Nature Monument was established to protect Lake Odlezy, the youngest natural lake in the Czech Republic, situated near Odlezly in western Bohemia. This lake was created in 1872 by a landslide that blocked the stream. The aquatic molluscs of this unique site were studied in 2013 and 2023. Altogether, 16 species (8 gastropods and 8 bivalves) were found at 13 sites. Molluscan communities in the streams, springs and small wetlands surrounding the lake are very poor, consisting of 1–4 species. In contrast, 13 species were found in the lake. Particularly notable are the probably extensive populations of mussels Anodonta cygnea and Unio tumidus, which are rare in western Bohemia.

Native molluscs alleviate water quality impacts of invasive crayfish

Freshwaters are considered to be the most vulnerable ecosystems facing biological invasions, and the red swamp crayfish (Procambarus clarkii) is one of the most widespread aquatic invasive species in the world. P. clarkii has negative impacts on water quality in the lakes that it invades by, for instance, increasing their turbidity and nutrient concentrations and reducing macrophyte biomass. However, native taxa such as snails and mussels could potentially help to maintain a clear-water status in lakes by grazing on periphyton or by phytoplankton filtration. To examine the potential negative effects of P. clarkii on the clear-water state in lakes dominated by the macrophyte Vallisneria denseserrulata and the potential for native species to buffer these effects, we tested the crayfish impact in the absence and presence of the snail Bellamya aeruginosa and the mussel Sinanodonta woodiana at different biomasses. In the presence of crayfish, total suspended solids, total phosphorus, and chlorophyll a concentrations significantly increased compared to the control treatments without crayfish. However, when crayfish coexisted with snails or mussels, these three environmental variables all decreased in concentration compared to the crayfish-only treatment. Low (500 g/m2) and high (1500 g/m2) snail or mussel biomass had similar buffering effects. Macrophyte biomass in the crayfish and high mussel biomass treatment was 43 % higher than in the crayfish-only treatment. Native molluscs therefore alleviated the negative effects of crayfish on lake water quality and promoted native macrophyte growth. We conclude that a thriving native mollusc community may help in maintaining the clear-water state in lakes following crayfish invasion.

Spatial distribution of two invasive freshwater snails and environmental correlates of the mollusc community abundance, a case study in Chile

Invasive species can produce negative effects on native species. We studied the densities of Physa acuta and Potamopyrgus antipodarum, two invasive freshwater snails in Chile, and analyzed the relationship between environmental parameters and the relative abundances of the mollusc community in several ecosystems. Densities of both species were studied in three habitat types (stones, smooth sediment, and vegetation) in the Consuelo Stream, Coquimbo Region. Densities of Potamopyrgus antipodarum were significantly higher on stones, while Physa acuta showed no significant differences between habitats. A canonical correspondence analysis (CCA) demonstrated that both Physa acuta and Potamopyrgus antipodarum were related to oxidation-reduction potential but not to salinity. The results also showed that native mollusc fauna is sparsely represented in the study area, possibly due to the presence of these invaders, although drought, water pollution, and other unstudied anthropogenic factors may also be involved.

THE ROLES OF MACROBENTHIC MOLLUSCS STRUCTURE IN ASSESSING ECOLOGICAL STATUS AT MANGROVE AND AQUACULTURE AREAS

stability of Coastal water ecosystem could have an effect on mangrove vegetation and anthrophogenic activities. This stability correlates significantly with the structure of the macrobenthic mollusk community in the area, some of this biota are bioindicator agents. This study aims to assess the ecological functions of macrobenthic molluscs, evaluate the spatial and temporal differences in their community structure, and analyze their correlation to environmental parameters in aquaculture and mangrove areas in the Karimunjawa Islands, Jepara, Central Java, Indonesia. Purposive random sampling method was conducted at KJABB-IMTA aquaculture and mangrove areas between July and September 2021. Collected data were analyzed using k-dominance curve, NMDS ordination, PCA, and BIO-ENV using Primer 6.1.5 software. Based on Paired T Test result, comparison between each location showed significant difference (t=15.916, P&lt;0.05, dF=5) meanwhile comparison between each sampling period showed insignificant result. The highest abundance and diversity were found in the aquaculture area and dominated by gastropods. Significant differences occurred in the structure of macrobenthic molluscs between the two study locations (t=15.916, P&lt;0.05, df=5), while the comparison between their composition and abundance between sampling times was not significant. The abiotic elements that primarily impact the structure of macrobenthic mollusks are the particle size composition of the substrate (mud) and dissolved oxygen (DO) based on PCA and BIO-ENV analysis (BIO-ENV; r=0.733).

Can the Empty Shells of Pinna nobilis Maintain the Ecological Role of the Species? A Structural and Functional Analysis of the Associated Mollusc Fauna

The endemic Mediterranean bivalve Pinna nobilis is a typical example of an autogenic ecosystem engineer in sedimentary environments, as it modifies the substrate, creates new complex 3D habitats and concentrates various species, thus increasing local biodiversity. Despite the significant loss of P. nobilis populations due to the epidemic mass mortality that occurred in several regions of the Mediterranean, including the northern Adriatic Sea, the numerous empty shells, still firmly anchored in the sediment, may continue to play the role of basibiont of this species. The persistence of this ecological function was here investigated on dead specimens of P. nobilis through the structural and functional study of the associated epibenthic mollusc community. A large number of mollusc taxa, characteristic of both infralittoral and sublittoral hard and soft bottoms, were identified in thirteen shells collected from four different sites in the Gulf of Trieste. Multivariate analysis revealed a clear separation between sites in terms of taxonomic composition, species abundance and biomass, with differences in expressed functional traits. Overall, considerable taxonomic and functional diversity was found, suggesting that the empty shells continue to provide a suitable habitat for a variety of molluscs that are closely linked to the surrounding environment and fulfil many different ecological functions.

Malacological remains from the Sambaqui da Tarioba (Rio das Ostras – RJ, Brazil): Marine mollusc biodiversity in the recent Holocene

The interpretation of archaeological sites of the sambaqui type (Brazilian shell middens) as proxies of past biodiversity is a promising approach. The sambaqui sites were built by prehistoric human populations between 8000 and 1000 BP, and they are extremely abundant on the Brazilian coast and bear information about the existing organisms at the time of their construction. In the current study, inferences about the past biological diversity of molluscs were made based on a profile of 1 m2 with a 1.3 m depth in sector HS-A1-e of the Sambaqui da Tarioba (Rio das Ostras, Rio de Janeiro, Brazil), which was dug in 2012. Sampling sufficiency was found for all five archaeo-stratigraphic layers in the site. The diversity indexes studied (Absolute Richness, Relative Richness, and Shannon and Simpson indexes) showed similar patterns to those of live mollusc communities. Non-parametric Kruskal-Wallis and Mann-Whitney tests did not reveal statistically significant differences in species abundance between layers. The diversity profiles built using the Rényi series showed that the mollusc diversity patterns in the Sambaqui da Tarioba varied along its 550 years of settlement, however, with no statistically significant difference among them. The taxonomic distinctness structure of the malacological diversity inventory for the Sambaqui da Tarioba was similar to a random sampling of the complete list of species currently found in the Rio das Ostras. Therefore, the current results indicate that although the information about biodiversity obtained from sambaqui sites could have some inaccuracy (because they are artificial accumulations), it is still relevant and prone to be accessed.