Bivalve distribution in hydrographic regions in South America: historical overview and conservation (original) (raw)
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Based on literature review and malacological collections, 168 native freshwater bivalve and five invasive species have been recorded for 52 hydrographic regions in South America. The higher species richness has been detected in the South Atlantic, Uruguay, Paraguay, and Amazon Brazilian hydrographic regions. Presence or absence data were analysed by Principal Coordinate for Phylogeny-Weighted. The lineage Veneroida was more representative in hydrographic regions that are poorer in species and located West of South America. The Mycetopodidae and Hyriidae lineages were predominant in regions that are richest in species toward the East of the continent. The distribution of invasive species Limnoperna fortunei is not related to species richness in different hydrographic regions there. The species richness and its distribution patterns are closely associated with the geological history of the continent. The hydrographic regions present distinct phylogenetic and species composition regardless of the level of richness. Therefore, not only should the richness be considered to be a criterion for prioritizing areas for conservation, but also the phylogenetic diversity of communities engaged in services and functional aspects relevant to ecosystem maintenance. A plan to the management of this fauna according to Guest editors:
Pereira et al 2013 Bivalve distribution in hydrographic regions in South America
Based on literature review and malacological collections, 168 native freshwater bivalve and five invasive species have been recorded for 52 hydrographic regions in South America. The higher species richness has been detected in the South Atlantic, Uruguay, Paraguay, and Amazon Brazilian hydrographic regions. Presence or absence data were analysed by Principal Coordinate for Phylogeny-Weighted. The lineage Veneroida was more representative in hydrographic regions that are poorer in species and located West of South America. The Mycetopodidae and Hyriidae lineages were predominant in regions that are richest in species toward the East of the continent. The distribution of invasive species Limnoperna fortunei is not related to species richness in different hydrographic regions there. The species richness and its distribution patterns are closely associated with the geological history of the continent. The hydrographic regions present distinct phylogenetic and species composition regardless of the level of richness. Therefore, not only should the richness be considered to be a criterion for prioritizing areas for conservation, but also the phylogenetic diversity of communities engaged in services and functional aspects relevant to ecosystem maintenance. A plan to the management of this fauna according to Guest editors:
The study of malacological fauna in hydric bodies is crucial to maintain the biodiversity in an environmental conservation area, since these organisms can interfere with water quality being potentially used as a bioindicator of environmental quality. This study aimed at identifying the diversity and population density of both native and invasive freshwater bivalves occurring in the APA of Verde River. Two sample collections were undertaken between July 2012 and March 2013. Three sampling sites (1 m 2 each) were delimited by using a PVC square in the riverbed, with a 50 m interval among them; after this procedure, the sediment contained in the sampling area was manually removed from a 10 cm depth. Then, the screening of live organisms and articulated valves was performed. The occurrence of native bivalves species was recorded as Anodontites tenebricosus, Diplodon parodizi, and the invasive mussel Corbicula fluminea. The higher population density was registered in March 2013 with 915 individuals (A. tenebricosus 4.66 ind/m 2 , D. granosus 1.0 ind/m 2 , C. fluminea 265.6 ind/m 2). The record of invasive species and the distribution of frequency analysis by length class frequency require continuous studies about the invasive species occurrence in the hydrographic basin of Verde River, because its spreading is closely related to the decline of the native bivalves population. Resumo. Avaliação da densidade de bivalves límnicos da Área de Proteção Ambiental (APA) do rio Verde, Campo magro, Paraná, Brasil. O estudo da fauna malacológica de corpos hídricos é fundamental para o conhecimento da diversidade de uma Unidade de Conservação. O objetivo do presente estudo foi identificar a diversidade de bivalves e a variação da densidade populacional de bivalves límnicos nativos e invasores com ocorrência na APA do Rio Verde. Em duas campanhas amostrais realizadas entre julho de 2012 e março de 2013, foram demarcados três pontos amostrais de 1m 2 utilizando-se quadrado de PVC disposto no leito do rio, em intervalos de 50 m. O sedimento contido na área demarcada foi removido, até uma profundidade de 10 cm e realizada triagem de organismos vivos e valvas articuladas. Foi registrada a ocorrência dos bivalves nativos Anodontites tenebricosus e Diplodon parodizi e do bivalve invasor Corbicula fluminea. Foram coletados 915 indivíduos vivos com a maior densidade registrada para março de 2013 (A. tenebricosus 4.66 ind./m 2 , D. parodizi 1.0 ind./m 2 e C. fluminea 265.6 ind./m 2). Os resultados obtidos demonstram que a espécie invasora é predominante na área de estudo e sua densidade populacional crescente pode determinar o declínio das populações de bivalves nativos.
First records of Freshwater Bivalves of Ilha Grande National Park, Paraná, Brazil
Iheringia. Série Zoologia, 2014
The Ilha Grande National Park, Paraná, Brazil, is located in the Upper Paraná River and has characteristics typical of a floodplains. This protected area includes lagoons connected and disconnected to the Paraná River, although the latter also connect during periods of high water level, thus composing a heterogeneous group of lacustrine environments. The enormous potential the flora and fauna diversities are still little known to the region, as can be seen through benthic invertebrates, inclunding bivalves mollusks. The granulometric composition of these floodplain lagoons was formed mainly by mud and very fine sand. Furthermore, organic matter composition was predominantly of fine particulate. The other abiotic factors differed from lagoons located within the island of the park to those located in the left margin of Paraná River. The results demonstrated the importance of abiotic factors such as the physical composition of granulometric texture, organic matter and macrophyte banks, to the establishment of bivalves in these floodplain lagoons. We recorded bivalves of Pisidium (native), Diplodon (native), and Corbicula (invasive).
The temperate zone of the southwestern Atlantic Ocean (23–42°S), which includes the Patagonian Shelf Large Marine Ecosystem and the Subtropical Convergence Zone, is one of the most productive areas of the Southern Hemisphere. Key features of this region are a wide continental shelf, the convergence of cold and warm currents, and continental freshwater input of the La Plata River. The Uruguayan marine and estuarine waters are at the core of this zone. The marine and estuarine bivalve fauna of Uruguay has received good attention since the publication of the Voyage of Alcide d'Orbigny (1834–1846). Here we provide an overview of taxonomic, faunistic and b iogeographic issues, identifying knowledge gaps and highlighting priorities for future research. The main threats for that fauna are discussed, with emphasis on species of current or potential socioeconomic interest. Of the 231 species reported from the area, only four species are strictly estuarine: Erodona mactroides Bosc, 1801, Tagelus plebeius (Lightfoot, 1786), Brachidontes darwinianus (d'Orbigny, 1842) and Mytella charruana (d'Orbigny, 1842). All of these have large biomasses, as is also the case for the marine eurihaline Mactra isabelleana d'Orbigny, 1846. A total of 112 deep-sea species (i.e., living deeper than 200 m) are recorded for the region, including almost every known group occurring elsewhere in deep-sea basins, with the exception of sunken wood associated species. Of these, 38 have been recorded only from the Argentine Basin. Some new records are preliminarily reported and discussed, including Acharax Dall, 1908 (Solemyidae), Lucinoma Dall, 1901, Graecina Cosel, 2006 (Lucinidae), and Callogonia Dall, 1889 (Vesicomyidae), all from the continental slope. A total of 19 warm and warm/temperate bivalve species have their southern distribution boundary in Uruguayan waters associated to warm waters of/or derived from the Brazil Current, including species distributed from the U.S.A. to Uruguay or from southeast Brazil to Uruguay. On the other hand, at least eight exclusively cold-water bivalves exhibit their northernmost distribution boundary off La Plata River; their occurrence there is associated with offshore sub-Antarctic waters. Uruguayan waters represent a critical biogeographical and ecological crossroads because of the complex interaction of currents and water masses. This region is thus particularly well suited as a system for the study of processes underlying biodiversity patterns. Pending challenges in taxonomic and biogeographic research will be successfully addressed only if multinational collaborative initiatives are undertaken in a framework of integrative taxonomy.
Biology and conservation of freshwater bivalves: past, present and future perspectives
Hydrobiologia, 2014
Freshwater bivalves have been highly threatened by human activities, and recently their global decline has been causing conservational and social concern. In this paper, we review the most important research events in freshwater bivalve biology calling attention to the main scientific achievements. A great bias exists in the research effort, with much more information available for bivalve species belonging to the Unionida in comparison to other groups. The same is true for the origin of these studies, since the publishing pattern does not always correspond to the hotspots of biodiversity but is concentrated in the northern hemisphere mainly in North America, Europe and Russia, with regions such as Africa and Southeast Asia being quite understudied. We also summarize information about past, present and future perspectives concerning the most important research topics that include taxonomy, systematics, anatomy, physiology, ecology and conservation of freshwater bivalves. Finally, we introduce the articles published in this Hydrobiologia special issue related with the International Meeting on Biology and Conservation of Freshwater Bivalves held in 2012 in Bragança, Portugal.
Diversity and abundance of economically important bivalves in north-western Bohol, Philippines
International Journal of Fisheries and Aquatic Studies, 2018
Diversity and abundance of bivalves found in mangroves and seagrass ecosystems of Northwestern, Bohol, Philippines were studied for five months using line transect method. Physico-chemical parameters such as depth, temperature, pH and dissolved oxygen in relation to occurrence of bivalves were also determined using CCA analysis. A total of 35 bivalve species were identified belonging to six orders, 14 families and 23 genera. Diversity index was higher in Calape (3.032) than Clarin (2.608) and Tubigon (2.607). This diversity index means that bivalves in Northwestern Bohol were in moderate condition. Meanwhile, the effect of earthquake was evident in the general evenness where Calape (0.63) was the highest while Clarin and Tubigon had similar result with 0.42 evenness index. This evenness index described ecological equilibrium in the community in which the value near to 1.00 means community is stable. Hence, Northwestern Bohol had unstable bivalve community. In terms of abundance, Clarin was the highest with 1085 total individuals. This was followed by Tubigon with 1022 and lowest in Calape with 853 total bivalves collected. Top five most abundant bivalves were Scapharca indica (24%), Scapharca cornea with 22% followed by Anomalocardia squamosa (7.9%), Gafrarium tumidum (6.5%) and Trachycardium rugosum (6%) respectively. These species of economically important bivalves with high abundance and distribution may be monitored for sustainability of wild stocks in the area. There may be a law regulating the intense collection of economically important bivalves in Northwestern Bohol to mitigate loss of these organisms knowing their unstable state.
Brazilian Journal of Oceanography, 1998
The spatial distribution of bivalve molluscs and its relation to granulometry and to the percentage of organic matter and silt-clay were studied in the Saco do Céu Inlet. Bivalves and samples of sediment were collected in 39 stations, in January and July 1992, using a 0.1 m2 Petersen grab. The type of sediment varied :&omvery fine to coarse sand. Nineteen species of bivalves were quantified, 14 of which were present in the two periods of the year. The highest diversity was found in medium and fine sand in summer and in coarse sand in winter. These bottoms presented a greater structural heterogeneity. A community dominated by Corbula caribaea was distinguished in fine bottoms with relative high content of organic matter, whereas another community dominated by Anomalocardia brasiliana occurred in coarser bottoms. Both communities were distributed in continuum a10nga sediment gradient.. Resumo: A distribuição espacial dos bivalves e sua relação com a granulometria e os teores de matéria orgânica e silte-argila foram estudados no Saco do Céu. Obteve-se amostras de fauna e sedimento em 39 estações nos meses de janeiro e julho de 1992, utilizando-se um busca-fundo de Petersen de 0,1 m2. O sedimento variou de areia fina a areia grossa. Foram quantificadas 19 espécies sendo que 14 ocorreram nos dois períodos do ano. Os fundos de areia média e [ma no verão e areia grossa no inverno apresentaram os maiores valores de diversidade e uma maior heterogeneidade estrutural. Evidenciou-se a existência de uma comunidade dominada por Anomalocardia brasiliana em fundos grossos e outra dominada por Corbula caribaea em fundos finos, ricos em matéria orgânica. Ambas distribuíram-se em contínuo, ao longo de um gradiente sedimentológico.
Bivalves of the São Sebastião Channel, north coast of the São Paulo State, Brazil
elements in trophic chains and are commercially relevant. Estimates suggest that there are about 1,000 marine bivalve species in Brazil; approximately 300 of these are believed to occur in São Paulo State, but only 191 were published (Simone 1999). Despite the importance of bivalves in the marine environment, there are few details on their distribution, especially on those species living subtidally at greater depths. Malacofaunal studies in the São Sebastião Channel include the pioneer survey of Ihering (1897), as well as the study of Migotto et al. (1993), which analyzed several locations along the channel, and the investigation of Salvador et al. (1998), which focused on the centralnorthern beaches of Ilhabela. Considering the absence of current data on bivalve diversity and distribution within the intertidal and subtidal zones of the north coast of the São Paulo State, this work aims to present an updated list of bivalve species within the São Sebastião Channel. Materials And Methods São Sebastião Channel is located between the municipalities of São Sebastião and Ilhabela on the north coast of São Paulo State, southeast Brazil; it is 25 km long, 2-7 km wide and up to 40 m deep in the central area (Netto et al. 2005; Oliveira et al. 2010). The climate is subtropical and water temperatures oscillate from 15 to 20°C (Migotto et al. 2001). The bivalves were obtained from sediment samples collected in the intertidal and subtidal zones between January 2010 and December 2012. Only living specimens with soft parts were considered in this survey.
Regional and temporal changes in bivalve diversity off the south coast of Portugal
2008
From 2000 to 2006, a total of 75 bivalve species were identified, varying from 29 (spring 2001) to 54 species (spring 2005) per year. Seasonal tendencies in diversity varied according to year, thus the interpretation of long-term and regional scales is essential before drawing any conclusions in other studies. Richness and diversity consistently decreased with depth and increased with sediment grain size (from low in very coarse sand to high in coarse silt). Diversity decreased progressively from 3 to 16 m depth, thus the harsher shallower environments (due to waves and tidal air exposure) showed greater diversity than the most stable areas. Communities in finer sediments were more diverse than those in coarser sand. Evenness showed patterns opposite to diversity, overall. Diversity and evenness maps (produced with multivariate universal kriging), showed that most geographic areas with greater diversity were farther from river outflows and wastewater treatment plants. Two types of geographic pattern were observed: areas with persistently greater bivalve diversity through time and areas that changed locally from year to year. This spatial analysis can be used to establish priority conservation areas for management purposes, and to analyse the persistency of regional diversity patterns. The area with most habitat heterogeneity (Sotavento) corresponded to greatest diversity. There was a positive relationship between Spisula solida and Chamelea gallina landings and bivalve diversity two years and one year later, respectively. Possibly, local fisheries, by selectively withdrawing the commercial numerically dominant species from the ecosystem, increased diversity one to two years later, as the ecological niches of the dominants are quickly filled by several other species thereby creating a more even community. It was not found any significant impact of local fisheries, on regional scales long term bivalve diversity