Potential impacts of the invasive species Corbicula fluminea on the survival of glochidia

Freshwater mussels (Bivalvia, Unionida) are one of the most imperilled faunal groups globally, being the introduction of invasive species a possible major mechanism of threat. The Asian clam Corbicula fluminea is a problematic invasive species in aquatic ecosystems and can impair the survival of parasitic larvae (glochidia) of native freshwater mussels. However, this possible mechanism of threat remains speculative and to date very few studies addressed quantitatively this issue. In order to cover this gap, we have performed a series of manipulative laboratory studies to assess how distinct densities of C. fluminea can affect the survival of glochidia after 6, 12, 24 and 48 h of exposure, using larvae of the native freshwater mussel Anodonta anatina. Our results suggest an increase in mortality of A. anatina glochidia with an increase in density of C. fluminea. Two main mechanisms may possibly explain our results: 1) the high filtration capacity of C. fluminea that can contribute to the mortality of glochidia due to the mechanical damage of their fragile shells when passing by siphons and/or digestive tract of C. fluminea and 2) the high excretion capacity of C. fluminea that can lead to mortality of glochidia due to increase in ammonia concentration. Mortality of glochidia was also time dependent with higher values registered after 48 h. This work is one of the first showing the influence of C. fluminea density on the survival of glochidia, being filtration (and consequent passage in the digestive tract) and biodeposition the main potential mechanisms explaining overall mortality. These results also suggest that sites with high densities of C. fluminea may be highly detrimental for the conservation of freshwater mussels, potentially impairing the survival of glochidia and negatively affecting the recruitment of juveniles.VM, MLL and PC were supported by doctoral grants (SFRH/BD/108298/2015), (SFRH/BD/115728/2016) and (SFRH/BD/131814/2017) from the Portuguese Foundation for Science and Technology - FCT through POPH/FSE funds. This study was conducted within the project FRESHCO - Multiple implications of invasive species on Freshwater Mussel coextinction processes, supported by FCT and COMPETE funds (contract: PTDC/AGRFOR/1627/2014). This study was also supported by the FCT project UID/Multi/04423/2019. We thank Allan Souza, Francisco Arenas, Jacinto Cunha and Lucia Guilhermino for their help in the design of the experiment. We also thank the editor and three anonymous referees for valuable suggestions

Um sistema simples para preparação de microesferas de quitosana

This article describes the construction and optimization of an inexpensive apparatus for the production of uniform and porous chitosan microspheres. It also describes the control of the main operational parameters and strategies for the production of uniform chitosan microspheres

Setting the stage for new ecological indicator species: A holistic case study on the Iberian dolphin freshwater mussel Unio delphinus Spengler, 1793

Supplementary data to this article can be found online at https://doi.org/10.1016/j.ecolind.2019.105987.Due to their sensitivity and dramatic declines, freshwater mussels are prime targets for conservation and environmental monitoring. For this, however, information is needed on life history and ecological traits, which is lacking in many taxa, including threatened species. Species recently described or recognized as valid are of particular concern, due to the shortage of even basic knowledge. A case in point is the recently recognized and Near Threatened dolphin freshwater mussel Unio delphinus Spengler, 1793, which is endemic to the western Iberian Peninsula and has suffered marked population declines. To overcome information gaps for U. delphinus, we carried out a holistic biological study across the species range, aiming to: i) estimate the area of occupancy (AOO) and extent of occurrence (EOO) based on updated distribution data taken from the literature and recent surveys; ii) estimate growth patterns from biometrical (shell dimensions and growth annuli) measurements taken on specimens from seven populations; iii) estimate sex ratios from gonad tissue biopsies collected on specimens from eight populations; iv) estimate gametogenesis and sex ratio through histological examination of gonad and gill tissues collected monthly for a year, from a single population; and v) determine host species from infestation trials of glochidia with co-occurring fish species. We estimated an EOO of 706 km2 and an AOO of 61 km2, which together with data on declines assigns the species to the Endangered category using IUCN criteria. Unio delphinus was found to grow faster and to be shorter-lived (up to 11 years, maturity at around 2 years old) than other European freshwater mussels. Growth and life span are similar across the range in lotic habitats, but different from that in lentic habitats. The larvae of U. delphinus may attach to most co-occurring fish species, but only native species were effective hosts. Native cyprinids, especially those from the genus Squalius, seem to be the primary hosts. Overall, the information provided contributes to a better conservation status assessment, selection of conservation and rehabilitation areas, guidance for the establishment of propagation programs and better timing for specimens’ manipulation including monitoring and possible translocations. The framework presented here highlights the importance of basic biological studies to define good ecological and physiological status.This work was supported by Portuguese FCT – Foundation for Science and Technology, Projects FRESHCO: Multiple implications of invasive species on Freshwater Mussel co-extinction processes (PTDC/AGR-FOR/1627/2014-04/SAICT/2015), MUSSELFLOW: Host-depen dent evolution, ecology and conservation of freshwater mussels under varying hydrological conditions: consequences of climate change (PTDC/BIA-EVL/29199/2017), and ConBiomics: The missing approach for the Conservation of freshwater Bivalves Project N° NORTE-01-0145- FEDER-030286, co-financed by COMPETE 2020, Portugal 2020 and the European Union through the ERDF. FCT also supported MLL under grant (SFRH/BD/115728/2016), CM under grant (SFRH/BD/111133/ 2015) and also through Strategic Funding UID/Multi/04423/2019. PB was supported by EDP Biodiversity Chair

Immunoreactivity of proteins within 30-40 kDa range during the acute and the recovery phases in rats experimentally infected with Strongyloides venezuelensis

In experimental infection with Strongyloides venezuelensis, the acute and recovery phases can be distinguished, unlike human infections caused by Strongyloides stercoralis. The objective of this study was to evaluate the production of anti-Strongyloides IgG antibodies and the recognition of immunogenic protein bands during the acute and the recovery phases in rats experimentally infected with S. venezuelensis. Rats were infected subcutaneously with 400 or 4,000 S. venezuelensis infective larvae. The acute phase was characterized by elimination of a large number of eggs in the faeces on days 6-14 post infection; the recovery phase was characterized by the resolution of the infection between days 30 and 35 post infection. Differences in IgG levels were observed in the acute and the recovery phases. Different antigenic fractions were recognized in both phases of infection. It is concluded that proteins within the 30-40 kDa range are immunoreactive markers for both the acute and the recovery phases in rats experimentally infected with S. venezuelensis, particularly using membrane antigen

Diagnóstico da qualidade do solo sob cultivo de pêssego em agroecossistemas de base familiar

O objetivo do estudo foi diagnosticar a qualidade do solo utilizando indicadores químicos, físicos, e biológicos, em pomares de cinco propriedades agrícolas familiares produtoras de pêssego, localizadas em Pelotas, Território Zona Sul do Rio Grande do Sul. Os resultados mostram que as condições físicas dos solos analisados apresentam-se, em geral, com níveis adequados e próximos das condições encontradas nas áreas de vegetação nativa. Já as condições químicas sugerem, pelos desempenhos dos indicadores considerados, níveis adequados de fertilidade do solo, variando os mesmos entre médio a alto. No entanto, as condições biológicas dos solos estão abaixo dos níveis adequados, indicando que a qualidade dos solos estudados está aquém do nível desejado, tendo em vista que essas condições são fundamentais para que o solo possa exercer adequadamente suas funções no agroecossistema.This study was conducted in five family agroecosystems in Pelotas, located in the South Zone of Rio Grande do Sul state. The aim of this study was to elaborate a diagnosis of soil quality under peach cultivation through analysis of physical, chemical and biological soil indicators. The results show that the physical conditions are adequate and similar to the areas of native vegetation. The chemical conditions presented appropriate levels of soil fertility, ranging between medium to high levels. However, the soil biological conditions were below the adequate level. Thus, the soil quality of these agroecossystems was considered inadequate, decreasing the soil capacity to function satisfactorily.Facultad de Ciencias Agrarias y Forestale

Diagnóstico da qualidade do solo sob cultivo de pêssego em agroecossistemas de base familiar

O objetivo do estudo foi diagnosticar a qualidade do solo utilizando indicadores químicos, físicos, e biológicos, em pomares de cinco propriedades agrícolas familiares produtoras de pêssego, localizadas em Pelotas, Território Zona Sul do Rio Grande do Sul. Os resultados mostram que as condições físicas dos solos analisados apresentam-se, em geral, com níveis adequados e próximos das condições encontradas nas áreas de vegetação nativa. Já as condições químicas sugerem, pelos desempenhos dos indicadores considerados, níveis adequados de fertilidade do solo, variando os mesmos entre médio a alto. No entanto, as condições biológicas dos solos estão abaixo dos níveis adequados, indicando que a qualidade dos solos estudados está aquém do nível desejado, tendo em vista que essas condições são fundamentais para que o solo possa exercer adequadamente suas funções no agroecossistema.This study was conducted in five family agroecosystems in Pelotas, located in the South Zone of Rio Grande do Sul state. The aim of this study was to elaborate a diagnosis of soil quality under peach cultivation through analysis of physical, chemical and biological soil indicators. The results show that the physical conditions are adequate and similar to the areas of native vegetation. The chemical conditions presented appropriate levels of soil fertility, ranging between medium to high levels. However, the soil biological conditions were below the adequate level. Thus, the soil quality of these agroecossystems was considered inadequate, decreasing the soil capacity to function satisfactorily.Facultad de Ciencias Agrarias y Forestale

Diagnóstico da qualidade do solo sob cultivo de pêssego em agroecossistemas de base familiar

O objetivo do estudo foi diagnosticar a qualidade do solo utilizando indicadores químicos, físicos, e biológicos, em pomares de cinco propriedades agrícolas familiares produtoras de pêssego, localizadas em Pelotas, Território Zona Sul do Rio Grande do Sul. Os resultados mostram que as condições físicas dos solos analisados apresentam-se, em geral, com níveis adequados e próximos das condições encontradas nas áreas de vegetação nativa. Já as condições químicas sugerem, pelos desempenhos dos indicadores considerados, níveis adequados de fertilidade do solo, variando os mesmos entre médio a alto. No entanto, as condições biológicas dos solos estão abaixo dos níveis adequados, indicando que a qualidade dos solos estudados está aquém do nível desejado, tendo em vista que essas condições são fundamentais para que o solo possa exercer adequadamente suas funções no agroecossistema.This study was conducted in five family agroecosystems in Pelotas, located in the South Zone of Rio Grande do Sul state. The aim of this study was to elaborate a diagnosis of soil quality under peach cultivation through analysis of physical, chemical and biological soil indicators. The results show that the physical conditions are adequate and similar to the areas of native vegetation. The chemical conditions presented appropriate levels of soil fertility, ranging between medium to high levels. However, the soil biological conditions were below the adequate level. Thus, the soil quality of these agroecossystems was considered inadequate, decreasing the soil capacity to function satisfactorily.Facultad de Ciencias Agrarias y Forestale

Freshwater mussel conservation: A global horizon scan of emerging threats and opportunities

We identified 14 emerging and poorly understood threats and opportunities for addressing the global conservation of freshwater mussels over the next decade. A panel of 17 researchers and stakeholders from six continents submitted a total of 56 topics that were ranked and prioritized using a consensus-building Delphi technique. Our 14 priority topics fell into five broad themes (autecology, population dynamics, global stressors, global diversity, and ecosystem services) and included understanding diets throughout mussel life history; identifying the drivers of population declines; defining metrics for quantifying mussel health; assessing the role of predators, parasites, and disease; informed guidance on the risks and opportunities for captive breeding and translocations; the loss of mussel-fish co-evolutionary relationships; assessing the effects of increasing surface water changes; understanding the effects of sand and aggregate mining; understanding the effects of drug pollution and other emerging contaminants such as nanomaterials; appreciating the threats and opportunities arising from river restoration; conserving understudied hotspots by building local capacity through the principles of decolonization; identifying appropriate taxonomic units for conservation; improved quantification of the ecosystem services provided by mussels; and understanding how many mussels are enough to provide these services. Solutions for addressing the topics ranged from ecological studies to technological advances and socio-political engagement. Prioritization of our topics can help to drive a proactive approach to the conservation of this declining group which provides a multitude of important ecosystem services.This publication is based upon work from COST Action CA18239, supported by COST (European Cooperation in Science and Technology). DCA was supported by Corpus Christi College and a Dawson Fellowship at St. Catharine's College, Cambridge. MLL was supported by FCT-Fundacao para a Ciencia e a Tecnologia (2020.03608.CEECIND). ISO was supported by a Whitten Studentship. INB was supported by the Russian Science Foundation (grant no. 21-17-00126). YVB was supported by RSF project no. 21-14-00092. KD was supported by the Czech Science Foundation (19-05510 S). TZ was supported by statutory funds of IOP PAN. MK was supported by funding through the Australian National Environmental Science Program. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission