Evolutionarily Significant Units Research Articles

Spatial ecology of closely related taxa: the case of the little shearwater complex in the North Atlantic Ocean

Abstract Seabirds inhabiting vast water masses provide numerous examples where opposing phenomena, such as natal and breeding philopatry vs. vagility have dug cryptic taxonomic boundaries among closely related taxa. The taxonomy of little shearwaters of the North Atlantic Ocean (Little–Audubon’s shearwater complex, Puffinus assimilis–lherminieri) still remains unclear, and complementary information on non-breeding distributions and at-sea behaviour becomes essential to unravel divergent local adaptations to specific habitats. Using miniaturized light-level geolocators from seven study areas in the North Atlantic, we evaluate the spatial and habitat segregation, estimate the timing of their key life-cycle events and describe the at-sea behaviour of three taxa of these little shearwaters year-round to distinguish ecological patterns and specializations that could ultimately unravel potential lineage divergences. We also assess morphometric data from birds that were breeding at each study area to further discuss potential adaptations to specific habitats. Our results show that, while birds from different taxa segregated in space and habitats, they share ecological plasticity, similar annual phenology and diel foraging behaviour. These ecological inconsistencies, while defining the evolutionary stressors faced by these taxa, do not suggest the existence of three Evolutionary Significant Units. However, they confirm the recent evolutionary divergence among the three little shearwaters of the North Atlantic.

The effect of landscape on functional connectivity and shell shape in the land snail Humboldtiana durangoensis.

The populations of Humboldtiana durangoensis have experienced a drastic reduction in the effective population size; in addition, the species is threatened by anthropogenic activities. For the aforementioned, landscape genetics will serve as a tool to define the potential evolutionarily significant units (ESU) for this species. To complete our objective, we evaluated the effect of cover vegetation and climate on the functional connectivity of the species from the last glacial maximum (LGM) to the present as well as the effect of climate on shell shape. Partial Mantel tests, distance-based redundance analysis and a Bayesian framework were used to evaluate connectivity. On the other hand, geometric morphometrics, phylogenetic principal component analysis and redundancy analysis were used for the analysis of shell shape. Our results suggest that the suitable areas have been decreasing since the LGM; also, vegetation cover rather than climate has influenced the genetic connectivity among land snail populations, although temperature had a high influence on shell shape in this species. In conclusion, vegetation cover was the main factor that determined the functional connectivity for the land snail; however, local selective pressures led to different phenotypes in shell shape that allowed us to postulate that each one of the previously defined genetic groups must be considered as a different ESU.

Giraffe taxonomy, geographic distribution and conservation

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Revisiting the Woolly wolf (Canis lupus chanco) phylogeny in Himalaya: Addressing taxonomy, spatial extent and distribution of an ancient lineage in Asia.

Of the sub-species of Holarctic wolf, the Woolly wolf (Canis lupus chanco) is uniquely adapted to atmospheric hypoxia and widely distributed across the Himalaya, Qinghai Tibetan Plateau (QTP) and Mongolia. Taxonomic ambiguity still exists for this sub-species because of complex evolutionary history anduse of limited wild samples across its range in Himalaya. We document for the first time population genetic structure and taxonomic affinity of the wolves across western and eastern Himalayan regions from samples collected from the wild (n = 19) using mitochondrial control region (225bp). We found two haplotypes in our data, one widely distributed in the Himalaya that was shared with QTP and the other confined to Himachal Pradesh and Uttarakhand in the western Himalaya, India. After combining our data withpublished sequences (n = 83), we observed 15 haplotypes. Some of these were shared among different locations from India to QTP and a few were private to geographic locations. A phylogenetic tree indicated that Woolly wolves from India, Nepal, QTP and Mongolia are basal to other wolves with shallow divergence (K2P; 0.000-0.044) and high bootstrap values. Demographic analyses based on mismatch distribution and Bayesian skyline plots (BSP) suggested a stable population over a long time (~million years) with signs of recent declines. Regional dominance of private haplotypes across its distribution range may indicate allopatric divergence. This may be due to differences in habitat characteristics, availability of different wild prey species and differential deglaciation within the range of the Woolly wolf during historic time. Presence of basal and shallow divergence within-clade along with unique ecological requirements and adaptation to hypoxia, the Woolly wolf of Himalaya, QTP, and Mongolian regions may be considered as a distinct an Evolutionary Significant Unit (ESU). Identifying management units (MUs) is needed within its distribution range using harmonized multiple genetic data for effective conservation planning.

Allopatric divergence and hybridization within Cupressus chengiana (Cupressaceae), a threatened conifer in the northern Hengduan Mountains of western China.

Having a comprehensive understanding of population structure, genetic differentiation and demographic history is important for the conservation and management of threatened species. High-throughput sequencing (HTS) provides exciting opportunities to address a wide range of factors for conservation genetics. Here, we generated HTS data and identified 266,884 high-quality single nucleotide polymorphisms from 82 individuals of Cupressus chengiana, to assess population genomics across the species' full range, comprising the Daduhe River (DDH), Minjiang River (MJR) and Bailongjiang River (BLJ) catchments in western China. admixture, principal components analysis and phylogenetic analyses indicated that each region contains a distinct lineage, with high levels of differentiation between them (DDH, MJR and BLJ lineages). MJR was newly distinguished compared to previous surveys, and evidence including coalescent simulations supported a hybrid origin of MJR during the Quaternary. Each of these three lineages should be recognized as an evolutionarily significant unit (ESU), due to isolation, differing genetic adaptations and different demographic history. Currently, each ESU faces distinct threats, and will require different conservation strategies. Our work shows that population genomic approaches using HTS can reconstruct the complex evolutionary history of threatened species in mountainous regions, and hence inform conservation efforts, and contribute to the understanding of high biodiversity in mountains.

Asexual propagation of two sea anemone taxa for Banggai cardinalfish microhabitat enhancement

The iconic symbiosis with clownfish is not the only sea anemone-fish association. Several tropical sea anemones provide microhabitat for the Endangered (IUCN Red List) Banggai cardinalfish Pterapogon kauderni. Microhabitat loss from declining sea anemone populations is a serious threat to native P. kauderni populations or evolutionarily significant units (ESUs). One measure advocated to maintain and rehabilitate these P. kauderni ESUs is to restore microhabitat abundance. The objective of this study was to evaluate the feasibility of the asexual propagation of wild anemone broodstock with the subsequent release. Two species with which P. kauderni commonly associates (Heteractis crispa and Entacmaea quadricolor) were identified through field surveys. Parent anemones were bisected, cutting through the center of the oral disc. Propagules (half anemones) were placed in empty clam shells as hard substrate. Treatments provided different levels of protection from potential predators, in aquaria (P. kauderni present/absent), concrete tanks (P. kauderni and Diadema urchins excluded/not excluded) or in a net cage on the natural substrate (fish and invertebrate fauna including P. kauderni and Diadema setosum). The cut edges of sectioned anemones joined together within seconds, with wounds typically healing in around 7 days and joins hard to see after 3-4 weeks. Growth was faster and long-term survival higher in the net cage compared to tanks for uncovered and covered anemones. The results indicate the potential for this propagation method in the context of P. kauderni conservation and suggest sectioned anemones should be moved to the natural rehabilitation areas once capable of adhering firmly to a hard substrate.

Himalayan wolf distribution and admixture based on multiple genetic markers

AbstractAimWe explore the phylogeography of Himalayan wolves using multiple genetic markers applied on a landscape‐scale dataset and relate our findings to the biogeographic history of the region.LocationHimalayas of Nepal, the Tibetan Plateau of China and mountain ranges of Central Asia.TaxonHimalayan wolf (also called the Tibetan wolf), Canis lupus chanco.MethodsWe present a large‐scale, non‐invasive study of Himalayan wolves from across their estimated range. We analysed 280 wolf scat samples from western China, Kyrgyzstan and Tajikistan at two mtDNA loci, 17 microsatellite loci, four non‐synonymous SNPs in three nuclear genes related to the hypoxia pathway, and ZF genes on both sex chromosomes.ResultsOur results corroborate previous studies showing that the Himalayan wolf forms a distinct lineage adapted to high altitudes in excess of 4,000 m elevation. We found a correlation between hypoxia adaptation and the divergent Himalayan wolf mtDNA haplotype found across the Tibetan Plateau of Qinghai, the Tibetan Autonomous Region and the Nepalese Himalayas. We identified a region of admixture between Himalayan and grey wolves at the boundary of their distributions, where the Tibetan Plateau elevation gradually drops.Main ConclusionBased on multiple genetic markers, the Himalayan wolf forms a reciprocally monophyletic lineage with a unique adaptation to high altitude. We propose that the divergence of the lineage is related to past uplift of the region, and that the lineage maintains its high‐altitude niche, in part, by means of its genetic adaptation to hypoxia. We conclude that the Himalayan wolf merits taxonomic recognition and designation as an evolutionary significant unit (ESU).

Filling a gap in Andean Cat Leopardus jacobita (Cornalia, 1865) (Mammalia: Carnivora: Felidae) distribution range: new record in La Rioja province, Argentina

A pelt of an Andean Cat specimen was discovered in La Rioja Province, Argentina, a region with no previous data recorded, located in a large distribution gap between the two currently identified evolutionarily significant units (ESU). This new record not only improves our knowledge about the species distribution but can also provide relevant genetic information for a better understanding of the relationship between the two ESU.

Phylogeographic study of the West Australian freshwater mussel, Westralunio carteri, uncovers evolutionarily significant units that raise new conservation concerns

South-western Australia is isolated from other forested regions of Australia by desert and bounded on southern and western sides by the Southern and Indian Oceans, respectively, with Westralunio carteri (Iredale, 1934) as the sole endemic freshwater mussel. Its conservation status is vulnerable. This species has a history of nomenclatural change and its systematic placement and population genetic history are largely unknown. We sampled 46 individuals from 13 sites across W. carteri’s distribution and sequenced two mitochondrial genes (16S rDNA and cytochrome c oxidase subunit I) and one nuclear gene (28S rDNA). The mitochondrial haplotype networks and COI phylogenies revealed three evolutionarily significant units (ESUs): “W. carteri” I including the west coast populations, “W. carteri” II from the south and south-eastern range, and “W. carteri” III only occurring in the south-western tip of Australia. Four species delimitation methods identified two molecular operational taxonomic units supporting two distinct species (“W. carteri” I and “W. carteri” II + III). Phylogeographic patterns revealed herein confirm the historical separation of Western and Southern paleo-basins, also highlighting the isolation of the south-western extremity of the region. This underlines the need for taxonomic revision and will require a re-evaluation of W. carteri’s conservation status.

High genetic connectivity in a gastropod with long-lived planktonic larvae

AbstractGenetic connectivity plays a crucial role in shaping the geographic structure of species. Our aim in this study was to explore the pattern of genetic connectivity in Bursa scrobilator, an iconic marine caenogastropod with long-lived pelagic larvae. Our study was based on the analysis of DNA sequence data for the 658-bp barcoding fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene. This is the largest DNA sequence dataset assembled to date for B. scrobilator. These data confirm that the two recently described subspecies B. scrobilator scrobilator (Linnaeus, 1758), from the Mediterranean and Macaronesia, and B. s. coriacea (Reeve, 1844), from West Africa, constitute two evolutionarily significant units (ESUs). We found that for the nominal subspecies, the variation in morphology (shell, radula and gross anatomy) and DNA sequences was not geographically structured, and this agrees with what we would expect in a species with high connectivity at the larval stage. The divergence between the two subspecies cannot be easily explained by isolation by distance, and we would argue that one or more extrinsic factors may have played a role in isolating the two ESUs and maintaining that isolation.

Rapid loss of flight in the Aldabra white-throated rail.

Flight loss has evolved independently in numerous island bird lineages worldwide, and particularly in rails (Rallidae). The Aldabra white-throated rail (Dryolimnas [cuvieri] aldabranus) is the last surviving flightless bird in the western Indian Ocean, and the only living flightless subspecies within Dryolimnas cuvieri, which is otherwise volant across its extant range. Such a difference in flight capacity among populations of a single species is unusual, and could be due to rapid evolution of flight loss, or greater evolutionary divergence than can readily be detected by traditional taxonomic approaches. Here we used genetic and morphological analyses to investigate evolutionary trajectories of living and extinct Dryolimnas cuvieri subspecies. Our data places D. [c.] aldabranus among the most rapid documented avian flight loss cases (within an estimated maximum of 80,000–130,000 years). However, the unusual intraspecific variability in flight capacity within D. cuvieri is best explained by levels of genetic divergence, which exceed those documented between other volant taxa versus flightless close relatives, all of which have full species status. Our results also support consideration of Dryolimnas [cuvieri] aldabranus as sufficiently evolutionary distinct from D. c. cuvieri to warrant management as an evolutionary significant unit. Trait variability among closely related lineages should be considered when assessing conservation status, particularly for traits known to influence vulnerability to extinction (e.g. flightlessness).

Taxonomic Delimitation of Species Complexes: A Challenge for Conservation; First Steps with the Abarema cochliacarpos Complex

Abstract—Taxonomic and ecological knowledge of plant species complexes informs their conservation status. Poorly delimited species boundaries can lead to incorrect assessments of biodiversity, and a rare species might have its distribution range overestimated if considering other closely related taxa as the same one. The present study investigates the level of morphometric variation within the Abarema cochliacarpos complex throughout its entire distribution range in the Brazilian Atlantic Forest and Caatinga vegetation, and considers the drivers of this variation. A morphometric study using cluster, PERMANOVA, and NMDS analyses was conducted. We analyzed patterns of trait variation among and within populations, and their relationship with environmental factors along with their geographical gradient. From the four morphotypes previously cited for the complex, the analyses delimited three morphological groups. Their morphological characteristics differed in response to environmental drivers. We identified morphological characters that differentiated the groups within the complex. The development of conservation strategies and actions to fully protect a species complex requires the understanding of the morphological variation within the complex. In the Abarema cochliacarpos complex different threats and challenges are associated with the conservation of each morphotype. We highlight the importance of conserving the various morphotypes of a species complex which has a large distribution range as evolutionary significant units, something that is frequently neglected in the published literature.

Distribution and current conservation status of the Mexican Goodeidae (Actinopterygii, Cyprinodontiformes).

The current distribution and abundance of the 40 species of Goodeidae fishes known from Mexico are described, and a total of 84 Evolutionarily Significant Units (ESUs) is designated within these species. Two species and four ESUs are likely extinct with no captive populations, and three species and eight ESUs are probably extinct in the wild but have at least one captive population in Mexico, the United States, or Europe. Of the 35 extant species, the analyses indicate that nine should be considered as critically endangered, 14 as endangered, nine as vulnerable, and only three as least concern. Twenty-seven of these species have experienced substantial declines in distribution or abundance or both since 2000, and only eight appear to have remained relatively stable. Of the 72 extant ESUs, our analyses indicate that 29 should be considered as critically endangered, 21 as endangered, 18 as vulnerable, and only four as least concern. Brief summaries of the historic and current distributions and abundance of each species are provided, as well as ESU. Three strategies are recommended to conserve Mexican goodeids: protect the best-quality remaining habitats where goodeids still persist, restore degraded habitat and re-introduce species or ESUs where practical, and establish captive populations to ensure continued survival of the many species and ESUs that will almost inevitably go extinct in the coming years. Limited resources require cooperation and collaboration between scientists, conservationists, and aquarium hobbyists for successful captive maintenance.

Assessing introgressive hybridization in roan antelope (Hippotragus equinus): Lessons from South Africa.

Biological diversity is being lost at unprecedented rates, with genetic admixture and introgression presenting major threats to biodiversity. Our ability to accurately identify introgression is critical to manage species, obtain insights into evolutionary processes, and ultimately contribute to the Aichi Targets developed under the Convention on Biological Diversity. The current study concerns roan antelope, the second largest antelope in Africa. Despite their large size, these antelope are sensitive to habitat disturbance and interspecific competition, leading to the species being listed as Least Concern but with decreasing population trends, and as extinct over parts of its range. Molecular research identified the presence of two evolutionary significant units across their sub-Saharan range, corresponding to a West African lineage and a second larger group which includes animals from East, Central and Southern Africa. Within South Africa, one of the remaining bastions with increasing population sizes, there are a number of West African roan antelope populations on private farms, and concerns are that these animals hybridize with roan that naturally occur in the southern African region. We used a suite of 27 microsatellite markers to conduct admixture analysis. Our results indicate evidence of hybridization, with our developed tests using a simulated dataset being able to accurately identify F1, F2 and non-admixed individuals at threshold values of qi > 0.80 and qi > 0.85. However, further backcrosses were not always detectable with backcrossed-Western roan individuals (46.7–60%), backcrossed-East, Central and Southern African roan individuals (28.3–45%) and double backcrossed (83.3–98.3%) being incorrectly classified as non-admixed. Our study is the first to confirm ongoing hybridization in this within this iconic African antelope, and we provide recommendations for the future conservation and management of this species.

The phylogeography of Vellozia auriculata (Velloziaceae) supports low zygotic gene flow and local population persistence in the campo rupestre, a Neotropical OCBIL

AbstractThe campo rupestre is a Neotropical azonal vegetation. Its disjoint distribution and the fact that it is an old climatic buffered infertile landscape (OCBIL) have been associated with the high diversity and endemism observed in this environment. Here, we tested whether a micro-endemic species from campo rupestre shows: (1) limited zygotic gene flow; (2) lower gametic than zygotic gene flow structure; (3) substrate-driven genetic structure and (4) no evidence of Pleistocene local extinction or recolonization. By sequencing intergenic plastid regions, phenotyping inter simple sequence repeats (ISSR) and modelling present and past species suitability distributions for Vellozia auriculata we conclude that (1) zygotic gene flow is limited; (2) gametic gene flow is recurrent, but limited by elevation and distance; (3) there is no support for genetic structure driven by substrate and (4) Pleistocene climatic changes did not restrict the species to refugia, with local persistence. As long-term gene flow restrictions may lead to differentiation and speciation, our data helps to corroborate that the campo rupestre is both a cradle (due to low zygotic gene flow, prolonged isolation and consequent differentiation) and a lineage museum (due to local survival during climate oscillations). We highlight two distinct evolutionarily significant units (ESU), providing information for better conservation practice.

High genetic variation and phylogeographic relations among Palearctic fairy shrimp populations reflect persistence in multiple southern refugia during Pleistocene ice ages and postglacial colonisation

AbstractIntense anthropogenic disturbance threatens temporary pond ecosystems and their associated fauna across the Palearctic. Since fairy shrimps (Crustacea, Branchiopoda) are endemic to temporary ponds, populations are declining due to habitat loss and it is important to define adequate units for conservation.Phylogeographic reconstructions, based on genetic variation, provide valuable information for defining evolutionary and conservation units, especially for organisms with high levels of cryptic diversity like many fairy shrimps. We studied a total of 152 individuals of the fairy shrimpBranchipus schaefferifrom 79 populations across the Palearctic and used mitochondrial (CO1) and nuclear (ITS1)DNAdata to reconstruct the phylogeography of the species.Our results show thatB. schaeffericomprises four highly diverged (10.3–16.5%) evolutionary clades. The present‐day haplotypes within each of the clades probably diverged from lineages that were maintained in separate refugia during the Pleistocene ice ages. While two clades represent distinct geographic regions, the two remaining clades have more wide and overlapping ranges. In addition, the limited number of shared haplotypes among populations from geographically distant regions within three of the clades suggest recent long‐distance dispersal events.Overall, the studiedB. schaefferidataset comprises high levels of genetic differentiation, without a clear morphological signal. Phylogenetic searches and pairwise genetic distances suggest that the studied lineages belong to a complex of four morphologically cryptic species. Since these four evolutionary old clades persist (±2 million years), despite overlapping geographic ranges and since they span a variety of ecological conditions, they should be considered as separate evolutionary significant units for conservation.

Linking epigenetics and biological conservation: Towards a conservation epigenetics perspective

Abstract Biodiversity conservation is a global issue where the challenge is to integrate all levels of biodiversity to ensure the long‐term evolutionary potential and resilience of biological systems. Genetic approaches have largely contributed to conservation biology by defining “conservation entities” accounting for their evolutionary history and adaptive potential, the so‐called evolutionary significant units (ESUs). Yet, these approaches only loosely integrate the short‐term ecological history of organisms. Here, we argue that epigenetic variation, and more particularly DNA methylation, represents a molecular component of biodiversity that directly links the genome to the environment. As such, it provides the required information on the ecological background of organisms for an integrative field of conservation biology. We synthesize knowledge about the importance of epigenetic mechanisms in (a) orchestrating fundamental development alternatives in organisms, (b) enabling individuals to respond in real‐time to selection pressures and (c) improving ecosystem stability and functioning. Using practical examples in conservation biology, we illustrate the relevance of DNA methylation (a) as biomarkers of past and present environmental stress events as well as biomarkers of physiological conditions of individuals; (b) for documenting the ecological structuring/clustering of wild populations and hence for better integrating ecology into ESUs; (c) for improving conservation translocations; and (d) for studying landscape functional connectivity. We conclude that an epigenetic conservation perspective will provide environmental managers the possibility to refine ESUs, to set conservation plans taking into account the capacity of organisms to rapidly cope with environmental changes, and hence to improve the conservation of wild populations. A free Plain Language Summary can be found within the Supporting Information of this article.

Effective population size and heterozygosity-fitness correlations in a population of the Mediterranean lagoon ecotype of long-snouted seahorse Hippocampus guttulatus

The management of endangered species is complicated in the marine environment owing to difficulties to directly access, track and monitor in situ. Population genetics provide a genuine alternative to estimate population size and inbreeding using non-lethal procedures. The long-snouted seahorse, Hippocampus guttulatus, is facing multiple threats such as human disturbance or by-catch, and has been listed in the red list of IUCN. One large population is found in the Thau lagoon, in the south of France. A recent study has shown this population belongs to a genetic lineage only found in Mediterranean lagoons that can be considered as an Evolutionarily Significant Unit (ESU) and should be managed with dedicated conservation strategies. In the present study, we used genetic analysis of temporal samples to estimate the effective population size of the Thau population and correlations between individual multilocus heterozygosity and fitness traits to investigate the possible expression of inbreeding depression in the wild. Non-invasive sampling of 172 seahorses for which profiles were pictured and biometric data recorded were genotyped using 291 informative SNPs. Genetic diversity remained stable over a 7-year time interval. In addition, very low levels of close relatedness and inbreeding were observed, with only a single pair of related individuals in 2008 and two inbreds in 2013. We did not detect departure from identity equilibrium. The effective population size was estimated to be Ne = 2742 (~ 40 reproductive seahorses per km2), larger than previously thought. No correlation was observed between heterozygosity and fluctuating asymmetry or other morphometric traits, suggesting a population with low variance in inbreeding. Together these results suggest this population does not meet conventional genetic criteria of an endangered population, as the population seems sufficiently large to avoid inbreeding and its detrimental effects. This study paves the way for the genetic monitoring of this recently discovered ESU of a species with patrimonial and conservation concerns.

An unexpected genetic diversity pattern and a complex demographic history of a rare medicinal herb, Chinese asparagus (Asparagus cochinchinensis) in Korea

Range-wide population studies of wide spread species are often associated with complex diversity patterns resulting from genetically divergent evolutionary significant units (ESUs). The compound evolutionary history creating such a pattern of diversity can be inferred through molecular analyses. Asparagus cochinchinensis, a medicinally important perennial herb, is in decline due to overharvesting in Korea. Eight A. cochinchinensis populations in Korea and three populations from neighboring countries (China, Japan and Taiwan) were examined using nine nuclear microsatellite loci and three chloroplast microsatellite loci to characterize molecular diversity patterns. The average within-population diversity was limited likely due to long-term bottlenecks observed in all eight populations. High pairwise FST values indicated that the populations have largely diverged, but the divergences were not correlated with geographic distances. Clustering analyses revealed a highly complex spatial structure pattern associated with two ESUs. Approximate Bayesian Computation (ABC) suggests that the two ESUs split about 21,000 BP were independently introduced to Korea approximately 1,800 years ago, and admixed in secondary contact zones. The two ESUs found in our study may have different habitat preferences and growth conditions, implying that the two genetically divergent groups should be considered not only for conservation and management but also for breeding programs in agricultural areas.

Freshwater conservation assessments in (semi-)arid regions: Testing river intermittence and buffer strategies using freshwater mussels (Bivalvia, Unionida) in Morocco

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.