Anthropogenic habitats may function as a refuge for some species, including freshwater mussels (Bivalvia, Unionida). In this study we assessed possible differences in density, size and condition ...index of the Moroccan freshwater pearl mussel Pseudunio marocanus (Pallary, 1918), formerly Margaritifera marocana, colonizing anthropogenic (sāqya = irrigation canal) and natural (Bouhlou River) habitats in Morocco. Results showed that the individuals colonizing the irrigation canal located on the left bank have a significantly higher density and condition index when compared to natural conditions, but no differences were found regarding size. Since this species is listed as critically endangered by the IUCN, being also considered among the 100 most endangered organisms in the planet, the presence of P. marocanus in anthropogenic habitats has high conservation importance. In fact, and despite no Moroccan freshwater pearl mussels were found on the irrigation canal located in the right bank, the one located on the left bank present stable conditions for the settlement of juveniles and, if managed carefully, for the future survival of the species. However, local authorities reported frequent dredging and cleaning activities by local farmers on this sāqya without any special attention devoted to Moroccan freshwater pearl mussels (or any other species) conservation. Therefore, the results reported here can be used by scientists, managers, politicians and local people to promote future management actions that enhance the Moroccan freshwater pearl mussel protection and guarantee their future survival, including on anthropogenic habitats.
•We evaluate the importance of anthropogenic habitats for a rare species.•Higher density and CI was found in canals than in natural habitats.•Irrigation canals provide stable conditions for Moroccan pearl mussels.•Management actions to protect pearl mussels should be urgently taken.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Information about biotic interactions (e.g. competition, predation, parasitism, diseases, mutualism, allelopathy) is fundamental to better understand species distribution and abundance, ecosystem ...functioning, and ultimately guide conservation efforts. However, conservation planning often overlooks these important interactions. Here, we aim to demonstrate a new framework to include biotic interactions into Marxan. For that, we use freshwater mussels and fish interaction (as mussels rely on fishes to complete their life cycle) in the Douro River basin (Iberian Peninsula) as a case study. While doing that, we also test the importance of including biotic interactions into conservation planning exercises, by running spatial prioritisation analysis considering either: 1) only the target species (freshwater mussels); 2) freshwater mussels and their obligatory hosts (freshwater fishes); 3) freshwater mussels, fishes and their interactions. With this framework we found that biotic interactions tend to be underrepresented when the data on both freshwater mussels and fishes is not simultaneously included in the spatial prioritisation. Overall, the priority areas selected across all scenarios are mostly located in the western part of the Douro River basin, where most freshwater mussels and fishes still occur. Given the low overlap of priority areas identified here and the current Natura 2000 network, our approach may be useful for establishing (or enlarging) protected areas, especially in light of the EU Biodiversity Strategy for 2030. Also, this work may provide guidance for future habitat restoration and management of main threats to freshwater biodiversity.
Display omitted
•Biotic interactions determine biodiversity patterns and ecosystem functioning.•Despite its importance, biotic interactions are rarely considered in conservation.•We demonstrate a novel framework to include biotic interactions in conservation planning.•We use freshwater mussels and their fish hosts in spatial prioritisation analyses.•Biotic interactions are less covered when not explicitly included in the analyses.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The use of non-physical barriers, particularly based on acoustic and luminous stimuli has been historically used to influence the behavior of fish, mainly for fishing purposes. Nowadays, behavioral ...barriers and guidance systems have been developed, not only to deter movements of fish, but also to promote behavioral responses with the objective of native fish protection, in particular the potamodromous species, reducing their mortality in the hydraulic structures of dams and guiding them towards transposition systems or to replacement habitats in regularized water bodies. This review details the use of acoustic and luminous systems and their evolution in recent years (Scopus 2012–2019) for the development of selective behavioral barriers for fish. We found that recent technologies try to identify new acoustic and luminous sensory ranges. Ambient sound, sound of predators or luminous spectral bands with different wavelengths have been used to selectively stimulate target and non-target species, in order to improve the effectiveness of repulsive/attractive systems for fish. Guidelines for future research in the area are also present.
DNA metabarcoding can contribute to improving cost‐effectiveness and accuracy of biological assessments of aquatic ecosystems, but significant optimization and standardization efforts are still ...required to mainstream its application into biomonitoring programmes. In assessments based on freshwater macroinvertebrates, a key challenge is that DNA is often extracted from cleaned, sorted and homogenized bulk samples, which is time‐consuming and may be incompatible with sample preservation requirements of regulatory agencies. Here, we optimize and evaluate metabarcoding procedures based on DNA recovered from 96% ethanol used to preserve field samples and thus including potential PCR inhibitors and nontarget organisms. We sampled macroinvertebrates at five sites and subsampled the preservative ethanol at 1 to 14 days thereafter. DNA was extracted using column‐based enzymatic (TISSUE) or mechanic (SOIL) protocols, or with a new magnetic‐based enzymatic protocol (BEAD), and a 313‐bp COI fragment was amplified. Metabarcoding detected at least 200 macroinvertebrate taxa, including most taxa detected through morphology and for which there was a reference barcode. Better results were obtained with BEAD than SOIL or TISSUE, and with subsamples taken 7–14 than 1–7 days after sampling, in terms of DNA concentration and integrity, taxa diversity and matching between metabarcoding and morphology. Most variation in community composition was explained by differences among sites, with small but significant contributions of subsampling day and extraction method, and negligible contributions of extraction and PCR replication. Our methods enhance reliability of preservative ethanol as a potential source of DNA for macroinvertebrate metabarcoding, with a strong potential application in freshwater biomonitoring.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Freshwater mussels are one of the most threatened animal groups in the world. In the European Union, threatened and protected mussel species are not adequately monitored, while species considered to ...be common and widespread receive even less attention. This is particularly worrying in the Mediterranean region, where species endemism is high and freshwater habitats are severely affected by water scarcity. In the absence of hard data on population trends, we report here a long-term comparison of freshwater mussel assemblages at 132 sites covering 15 different hydrological basins in Portugal. This study reveals a widespread decline of 60 % in the number of sites and 67 % in the overall abundance of freshwater mussels across Portugal over the last 20 years, indicating that all species are rapidly declining and threatened with extinction. These results show that current legislation and conservation measures are largely ineffective and highlight the importance of updating the Habitats Directive to enforce standard monitoring protocols for threatened species in the European Union and to extend monitoring to other freshwater species thought to be common and widespread. Efficient water management, restrictions on irrigation expansion in important biodiversity areas, mitigation of hydrological changes and loss of aquatic habitat connectivity caused by physical alterations are urgently needed to reverse these declining population trends. For the severely endangered species Margaritifera margaritifera, Potomida littoralis, and Unio tumidiformis, where populations are now critically low, more urgent action is needed, such as ex-situ conservation, protection of remaining populations and large-scale habitat restoration.
•Protected freshwater mussels are ineffectively monitored in the European Union.•Common freshwater mussel species are generally not monitored.•Long-term survey reports a massive decline of freshwater mussel species in Portugal.•Water depletion, dams and invasive species are the main causes of decline.•Improved water and catchment management urgently needed.•Changes to the Habitats Directive proposed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The IUCN Red List assessments are essentially based on population trends and range, namely Area of Occupancy (AOO) and Extent of Occupancy (EOO). Range estimations are based on fixed grids, but this ...is likely inappropriate for species living in river networks. Furthermore, AOO and EOO are measured using the whole hydrographic network, therefore disregarding temporary sections, which is particularly problematic in arid and semi-arid regions. Here we mapped the permanent hydrographic network of Morocco using satellite imagery, complemented with field surveys to collect samples for molecular analyses of the five freshwater mussel species present and assess their distribution. The phylogeographic patterns are described for each species and used to identify priority areas and evolutionary significant units for conservation. Permanent hydrographic river sections represent only 18.3% of the whole hydrographic network. A north-to-south gradient of genetic diversity, species richness and distribution range was found, being coherent with water availability and river intermittence. Isolated evolutionary units were detected in southern basins that should also receive particular attention in conservation planning. We propose the mean river width multiplied by the extent of the river network as the best and the most adequate way to estimate both EOO and AOO. Given the worldwide degradation of freshwater systems and biodiversity, an accurate (re)assessment of species conservation status supported with maps of intermittent water bodies will be essential for prioritizing and guiding conservation actions and management plans, especially in arid and semi-arid regions.
•EOO/AOO estimates for freshwater taxa should use river width, not 2 km grid standard.•We produced a geo-referenced permanent water-only river network of Morocco (18%).•Moroccan Anodonta is A. anatina.•North-south gradient of genetic diversity, species richness and river intermittence•Conservation status of Moroccan freshwater mussel species was updated.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Display omitted
•Freshwater mussels were surveyed comprehensively in the East Mediterranean Region.•Voucher specimens and tissue snips were collected for genetics.•COI barcoding and species ...delineation methods are applied to all available genera.•New phylogeny and systematics of the East Mediterranean Unionidae are provided.•Biogeographic and conservation considerations are provided.
Located at the junction between Europe, Africa, and Asia, with distinct evolutionary origins and varied ecological and geographical settings, together with a marked history of changes in orogeny and configuration of the main river basins, turned the Eastern Mediterranean into a region of high diversity and endemism of freshwater taxa.
Freshwater mussels (Bivalvia, Unionidae) from the Western Palearctic have been widely studied in their European range, but little attention has been dedicated to these taxa in the Eastern Mediterranean region and their diversity and phylogeography are still poorly understood.
The present study aims to resolve the diversity, biogeography, and evolutionary relationships of the Eastern Mediterranean freshwater mussels. To that end, we performed multiple field surveys, phylogenetic analyses, and a thorough taxonomic revaluation. We reassessed the systematics of all Unionidae species in the region, including newly collected specimens across Turkey, Israel, and Iran, combining COI + 16S + 28S and COI phylogenies with molecular species delineation methods. Phylogeographical patterns were characterized based on published molecular data, newly sequenced specimens, and species distribution data, as well as ancestral range estimations.
We reveal that Unionidae species richness in the Eastern Mediterranean is over 70% higher than previously assumed, counting 19 species within two subfamilies, the Unioninae (14) and Gonideinae (5). We propose two new species, Anodonta seddonisp. nov. and Leguminaia anatolicasp. nov. Six additional taxa, Unio delicatusstat. rev., Unio eucirrusstat. rev., Unio huetistat. rev., Unio sesirmensisstat. rev., Unio terminalisstat. rev. removed from the synonymy of Unio tigridis, as well as Unio damascensisstat. rev. removed from the synonymy of Unio crassus, are re-described. The nominal taxa Unio rothi var. komarowi O. Boettger, 1880 and Unio armeniacus Kobelt, 1911 are proposed as new synonyms of Unio bruguierianus, and Anodonta cyrea Drouët, 1881 and Anodonta cilicica Kobelt & Rolle, 1895 as new synonyms of Anodonta anatina. Also, the presence of Unio tumidus in the Maritza River is confirmed. The phylogeographic patterns described here are interpreted concerning major past geological events.
Conservation needs and implications are presented, together with populations and species conservation priorities.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Freshwater mussels of the order Unionida have been dramatically declining globally. Despite their ecological importance, conservation of these animals has been hindered by unresolved taxonomy and a ...lack of data on the distribution and status of populations, especially in southern Europe. Although the Italian Peninsula has been noted as a centre of endemism and one of the major refugia of the glacial ages for several taxa, few studies have been performed on the genetic diversity of Unionida. Most importantly, the taxonomic status of several freshwater mussel populations of the Italian Peninsula is still unresolved. Here we present the first comprehensive dataset for the Unionida of the region spanning Italy and the coastal Croatian region (west of the Dinaric Alps). In total, 191 specimens were collected (85
Anodonta,
64
Unio
, 17
Microcondylaea bonellii
and 25
Sinanodonta woodiana
) from 34 sites across the Italian Peninsula and coastal Croatian river basins for molecular identification (COI, 16S and 28S). Genetic analyses were performed to understand major phylogenetic and phylogeographic patterns. Seven species were detected: three
Anodonta
species (
A. anatina
,
A. cygnea
and
A. exulcerata
), two
Unio
species (
U. mancus
and
U. elongatulus
),
Microcondylaea bonellii
, and the invasive
Sinanodonta woodiana
. The presence of three endemic species (
A. exulcerata
,
U. elongatulus
and
M. bonellii
) confirms the importance of the region as a centre of endemism for freshwater mussels. The Apennine Mountains act as an important biogeographic barrier.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Theidentification of key biodiversity areas (KBA) was initiated by the International Union for Conservation of Nature in 2004 to overcome taxonomic biases in the selection of important areas for ...conservation, including freshwater ecosystems. Since then, several KBAs have been identified mainly based on the presence of trigger species (i.e., species that trigger either the vulnerability and or the irreplaceability criterion and thus identify a site as a KBA). However, to our knowledge, many of these KBAs have not been validated. Therefore, classical surveys of the taxa used to identify freshwater KBAs (fishes, molluscs, odonates, and aquatic plants) were conducted in Douro (Iberian Peninsula) and Sebou (Morocco) River basins in the Mediterranean Biodiversity Hotspot. Environmental DNA analyses were undertaken in the Moroccan KBAs. There was a mismatch between the supposed and actual presence of trigger species. None of the trigger species were found in 43% and 50% of all KBAs surveyed in the Douro and Sebou basins, respectively. Shortcomings of freshwater KBA identification relate to flawed or lack of distribution data for trigger species. This situation results from a misleading initial identification of KBAs based on poor (or even inaccurate) ecological information or due to increased human disturbance between initial KBA identification and the present. To improve identification of future freshwater KBAs, we suggest selecting trigger species with a more conservative approach; use of local expert knowledge and digital data (to assess habitat quality, species distribution, and potential threats); consideration of the subcatchment when delineating KBAs boundaries; thoughtful consideration of terrestrial special areas for conservation limits; and periodic field validation.
Alarming decline of freshwater trigger species in western Mediterranean Key Biodiversity Areas
Resumen
La identificación de las áreas clave de biodiversidad (ACB) fue iniciada por la Unión Internacional para la Conservación de la Naturaleza en 2004 con el objetivo de sobreponerse a los sesgos taxonómicos en la selección de áreas importantes para la conservación, incluyendo los ecosistemas de agua dulce. Desde entonces, varias ACB han sido identificadas principalmente con base en la presencia de especies desencadenantes (es decir, especies que desencadenan el criterio de vulnerabilidad o de carácter irremplazable y por lo tanto identifican a un sitio como una ACB). Sin embargo, a nuestro conocimiento, muchas de estas ACB no han sido validadas. Por lo tanto, los censos clásicos de taxones utilizados para identificar las ACB de agua dulce (peces, moluscos, odonatos y plantas acuáticas) fueron realizados en las cuencas de los ríos Duero (Península Ibérica) y Sebou (Marruecos) en el Punto Caliente de Biodiversidad del Mediterráneo. Realizamos análisis de ADN ambiental en las ACB de Marruecos. Hubo una discrepancia entre la supuesta presencia y la actual presencia de especies desencadenantes. Ninguna de las especies desencadenantes se encontró en 43% y 50% de las ACB censadas en las cuencas del Duero y del Sebou, respectivamente. Las deficiencias en la identificación de las ACB de agua dulce están relacionadas con la carencia de datos o datos erróneos sobre la distribución de las especies desencadenantes. Esta situación resulta en una identificación inicial engañosa de las ACB con base en información ecológica deficiente (o incluso incorrecta) o también puede deberse al incremento en las perturbaciones humanas ocurridas entre la identificación de la ACB y el presente. Para mejorar la identificación de ACB de agua dulce en el futuro, sugerimos que la selección de especies desencadenantes se realice con un enfoque más conservador; que se usen el conocimiento local de los expertos y los datos digitales (para evaluar la calidad del hábitat, la distribución de las especies y las amenazas potenciales); que se consideren las subcuencas cuando se delimiten las fronteras de las ACB; que se consideren cuidadosamente las áreas de especies terrestres para los límites de conservación; y que se realicen validaciones periódicas de campo.
Article impact statement: The delineation of some KBAs and their focal areas has shortcomings related to flawed data or lack of distribution data for trigger species.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Aim
Freshwater mussels are among the most threatened taxa in the world, partially due to the dependence on fish hosts to complete their life cycle. Knowledge about the role of environmental and ...biotic drivers in determining mussels' distribution is currently lacking. We aimed to assess the role of environmental and biotic drivers in determining the distribution of mussels and their fish hosts and to test if co‐occurrence patterns were able to identify mussel‐host interactions.
Location
Douro River basin (Iberian Peninsula).
Taxon
Four freshwater mussels and ten fish hosts.
Methods
Joint species distribution models (JSDMs) were fitted to presence‐absence records for mussel and fish assemblages. Variance partitioning among environmental variables and latent variables was conducted to determine the environmental versus biotic drivers of species distributions. Resulting matrices of pairwise species co‐occurrences were used to identify co‐occurrence patterns.
Results
The distribution of host generalist mussel species was mainly explained by environmental variables related to climate and topography. The distribution of the host specialist Margaritifera margaritifera was mainly explained by land use. Strong positive correlations between mussels and the most relevant fish hosts were consistently captured by JSDMs. Co‐occurrence patterns were mainly explained by residual factors, indicating the potential role of biotic interactions.
Main Conclusions
Biotic interactions were expected to play an important role in explaining mussels' distribution, but the contribution of this factor was only meaningful for the host specialist M. margaritifera. Correlations between mussels and suitable hosts allowed to infer important fish hosts for freshwater mussels in the Douro River basin from distributional data alone. By finding similarities between the ecological requirements of co‐occurring species, conservation measures can be oriented towards several species, which brings a more holistic perspective to the protection of biodiversity.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
