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Alexandra Zieritz Leonardo Jainih John Pfeiffer Khairul Adha A. Rahim Hari Prayogo Muhammad Sofwan Anwari Arman Hadi Fikri Farah Diba Hussein Taha Zohrah Sulaiman Elsa Froufe Manuel Lopes-Lima 《水产资源保护:海洋与淡水生态系统》2021,31(11):3169-3183
- Most of the Bornean endemic freshwater mussel (Unionida) species known to date have not been recorded by science for the past 50 years or more, owing to a lack of research effort and presumed population losses.
- This study assessed current patterns and recent changes in the diversity and distribution of freshwater mussels in north-eastern Borneo. Physical surveys and interviews were conducted at 24 sites, and anecdotal evidence for current or historical presence of mussels was collected for a further 13 sites.
- Native species, i.e. Schepmania sp. and Khairuloconcha sahanae gen. & sp. nov., were only found in one small stream of the Kinabatangan River basin within the Gomantong Forest Reserve, whereas the non-native Sinanodonta cf. woodiana was common across the study area.
- Molecular phylogenetics (five genes) of the native taxa, including comparative material from West Kalimantan and Sarawak, revealed: (i) the presence of a new genus with two new, rare species: Khairuloconcha lunbawangorum sp. nov. in the Limbang River basin and K. sahanae in the Kinabatangan River basin; (ii) that Khairuloconcha and Ctenodesma form the Bornean endemic tribe Ctenodesmini trib. nov.; and (iii) that Schepmania represents another Bornean endemic tribe Schepmaniini trib. nov.
- Both Khairuloconcha gen. nov. species are known from a single stream each and are apparently restricted to forest stream habitats where they occur at very low densities. Schepmania appears to have a severely contracted range in the Kinabatangan and adjacent basins. We urgently call for full protection of the currently known sites of K. lunbawangorum and K. sahanae, and development of an action plan to save the Bornean freshwater mussel fauna.
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Conservation of fish communities: Extending the ‘research life cycle’ by achieving practical effects
- This article highlights the practical impact of our 2018 Aquatic Conservation: Marine and Freshwater Ecosystems publication, ‘Importance of peripheral basins: Implications for the conservation of fish assemblages’, which described fish communities in a Polish river.
- Data on the fish assemblages of the Dniester River (Black Sea basin) are scarce; however, evidence indicates that the assemblages have declined. In our 2018 study, we hypothesized that the peripheral basin (the small basin on the edge) of the larger Upper Dniester River basin (the Strwi?? River) could maintain good ecological status and contained unique fish assemblages.
- To examine the influence of historical factors and assess the role of peripheral basins on fish conservation, data from the Strwi?? basin were compared with the adjacent but unconnected Wiar basin (the Vistula basin; Baltic Sea basin). The Strwi?? River fish assemblages featured higher species richness and a greater number of native Ponto–Caspian species that function near the edge of their ranges.
- This article focuses on four impacts of the 2018 publication: increasing awareness by various groups and organizations of the unique character of the surveyed river basin; highlighting important issues in assessing the ecological status of European rivers; driving the red‐listing of species and the development of stream fish conservation strategies; and identifying possible future impacts.
- Our 2018 publication demonstrated the value of studying peripheral basins, which may affect conservation strategy development and encourage study of the importance of other peripheral basins and their role in aquatic resources conservation. Our article influenced the interpretation of fish‐based biotic indices and the conduct of monitoring work and its evaluation. It also strongly emphasized the native origin of the racer goby (Babka gymnotrachelus) in the Strwi?? River, which was important for subsequent works seeking to change the legal status of the species in Poland.
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- 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.
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Iana Tavares Favero Gabriel Eduardo Favero Katherine Fiedler Choi‐Lima Heleno Francisco dos Santos Joo Pedro Souza‐Alves Josenildo de Souza e Silva Joo Lucas Leo Feitosa 《水产资源保护:海洋与淡水生态系统》2020,30(8):1665-1673
- The West Indian manatee (Trichechus manatus) is a Vulnerable species threatened by habitat loss in the coast of north‐eastern Brazil. This study investigates how the distribution and habitat use of the West Indian manatee is influenced by resource availability in a scenario of freshwater limitation.
- Land‐based and boat surveys were conducted to record manatee sightings and habitat use, in a total of 206 hours of observation.
- Manatee abundance was significantly influenced by freshwater availability, with greater abundances occurring close to freshwater sources. Food availability and the variation in freshwater availability between seasons were also important to determine their distribution. For the 47 manatees sighted, 39 were recorded during the rainy season and eight during the dry season.
- Habitat use was influenced by freshwater sources and manatees spent more time (average coefficient of area use = 24.96%) in areas with greater availability of fresh water. Under conditions of freshwater limitation, manatees were more abundant and spent more time closer to fresh water than to food sources; as a result, animals' distribution varied between seasons.
- The results found here can help to determine conservation strategies for the region with the highest population density and genetic variability of West Indian manatees in Brazil.
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Mark G. Allen David L. Morgan Paul G. Close Stephen J. Beatty 《水产资源保护:海洋与淡水生态系统》2020,30(7):1412-1423
- 1. Small‐bodied freshwater fishes are commonly overlooked in threatened species management despite being highly imperilled. Before this study, the newly described little pygmy perch (Nannoperca pygmaea) was known from only 0.06 km2 of habitat in a single catchment in south‐western Australia and a lack of knowledge prevented an understanding of its conservation status and priority actions.
- 2. The present study determined the distribution, biology, and movement patterns of N. pygmaea and compared these with other small, sympatric percihthyids to assess its conservation status and likely resilience to threatening processes.
- 3. The current ‘extent of occurrence' of N. pygmaea was determined to be 3,420 km2 and the ‘area of occupancy' was 10 km2. Nannoperca pygmaea inhabited permanent refuge pools in the main stem of an ephemeral, secondarily salinized catchment where salinities remained <6 ppt during summer.
- 4. During winter N. pygmaea undertook a short upstream migration into a seasonally flowing freshwater tributary to serially spawn. The timing of reproduction was partitioned among three sympatric pygmy perches within the austral winter/spring period.
- 5. The species qualifies as ‘Endangered' under the IUCN Red List assessment criteria. Its restriction to freshwater refugia within salinized rivers suggests that N. pygmaea may have a limited salinity tolerance similar to the sympatric, threatened Nannatherina balstoni, and that the species is susceptible to prolonged drought, drying of critical baseflow refuges, increasing salinization, and introductions of alien species.
- 6. The study serves as an example that small‐bodied freshwater fishes need greater research attention to understand the biological and environmental mechanisms underpinning their decline.
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Igor Christo Miyahira Maria Cristina Dreher Mansur Luiz Eduardo Macedo de Lacerda Isabela Cristina Brito Gonçalves Glauco Gil Sant'Anna Sonia Barbosa dos Santos 《水产资源保护:海洋与淡水生态系统》2023,33(1):102-114
- Bivalves are important components of freshwater ecosystems; however, they are also one of the most threatened animal groups, especially members of the order Unionida. The main threats to freshwater bivalves are habitat modification and invasive species. Protected areas are a common way to minimize impacts and preserve native species, but they are rarely designated with a focus on freshwater invertebrates.
- The main goal of this article was to describe the distribution of freshwater bivalves in the state of Rio de Janeiro, and the relationship between these species and bioclimatic areas, land use and protected areas.
- Five native and two invasive bivalve species have been reported in Rio de Janeiro. They occur mainly in bioclimatic areas related to the Paraíba do Sul River and Campista Lowlands. The few records of bivalves inside protected areas are in areas of sustainable use that offer a lower level of protection, and frequently in sympatry with invasive bivalves.
- Thus, the established protected areas in Rio de Janeiro are not adequately effective for freshwater bivalve conservation, and some species remain under threat even within them. Freshwater bivalves thus remain largely unprotected in the state.
- The development of new protected areas and management plans should consider other faunal groups that are usually ignored, such as freshwater bivalves, to achieve more inclusive and effective protection.
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Ana Rita Dias Amílcar Teixeira Manuel Lopes‐Lima Simone Varandas Ronaldo Sousa 《水产资源保护:海洋与淡水生态系统》2020,30(5):988-999
- Coextinction is the simplest form of secondary extinction and freshwater mussels (Bivalvia, Unionida) may be particularly prone to this phenomenon as their life cycle includes an obligatory parasitic larval stage on fish hosts.
- The main aims of this study were to determine the possible ecological fish hosts of Anodonta anatina (Linnaeus, 1758) in several rivers of the Douro basin in northern Portugal and to assess possible spatial and temporal differences in glochidial (larval) loads. In order to achieve this, electrofishing was conducted from December to April, the fish fauna was characterized, and levels of infestation with A. anatina glochidia were determined.
- Native cyprinid species, mainly Luciobarbus bocagei (Iberian barbel) and Squalius carolitertii (northern Iberian chub), together with the non‐native Lepomis gibbosus (pumpkinseed sunfish) and Alburnus alburnus (common bleak), were found to have the highest glochidial loads. Clear differences in infestation between rivers and throughout time were detected, with an infestation period from January to March, and with the Tâmega River having the highest prevalence.
- Anodonta anatina is able to infest a variety of fish species, and this together with earlier studies showed that the metamorphosis into juveniles occurs mainly in native cyprinid species, although non‐native species like common bleak can also be considered suitable hosts. However, the larvae infesting other non‐native species, such as the pumpkinseed sunfish, do not metamorphose and can be considered ‘dead ends’.
- Overall, the results reported here are important for the conservation of A. anatina (and other unionoid species) because several Iberian rivers (and worldwide) have been subjected to the extirpation of native fish species and the introduction of non‐native fish species. Therefore, careful assessments of fish communities should be conducted to assess possible negative interactions with freshwater mussels.
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Lydia X. Gan Claudia L. Y. Tan Amirrudin B. Ahmad Yixiong Cai Darren C. J. Yeo 《水产资源保护:海洋与淡水生态系统》2023,33(1):89-101
- Commodity-driven forest conversion represents one of the most severe threats to freshwater biodiversity in Southeast Asia, notably causing population declines and the extinction of freshwater fish species.
- Although a variety of freshwater taxa are likely to be adversely affected by forest conversion, little is known about the impact on ecologically and economically important invertebrates such as decapod crustaceans.
- This study evaluated the impact of forest conversion and land-use change on freshwater Macrobrachium shrimp species, using species richness, abundance, and environmental data collected from 20 streams across southern Peninsular Malaysia. Streams were located in three types of landscape: forest; oil palm plantation; and mixed land use, comprising young secondary forest, small-scale plantations, patches of open and sparsely vegetated areas, and agricultural fields and clearings.
- Generalized linear models showed that even incomplete change from forest habitats to mixed land use and oil palm plantation resulted in significantly lower Macrobrachium native species richness and higher non-native species abundance. Native species richness was positively correlated with canopy cover, leaf litter, substrate size, and dissolved oxygen, and was negatively correlated with water temperature and conductivity. Native species richness was also negatively correlated with non-native species abundance, with non-native species abundance increasing along the human disturbance gradient.
- These results highlight the need for riparian habitat protection to conserve native Macrobrachium and limit the spread of non-native species. A management priority should be to maintain or restore optimum instream habitat conditions for shrimps, which would also benefit fish and other benthic macroinvertebrates. Suitable riparian management requires substantial support and funding from multiple stakeholders, but it can be aligned with other catchment-based strategies to optimize the use of limited resources available for freshwater biodiversity conservation.
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