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Forest fragmentation and introduced pathogens are negatively impacting trees and forests globally including the Carolinian forest of southern Ontario, Canada. Multiple species at risk live in this threatened but biodiverse forest, including the endangered Cornus florida (eastern flowering dogwood), which is now limited to fragmented woodlots, and has been decimated by the introduced fungal pathogen Discula destructiva (dogwood anthracnose). Ongoing management of C. florida in Canada is challenged by multiple knowledge gaps, two of which we aimed to address in this study. We first evaluated the association between anthracnose disease prevalence and a suite of ecological and environmental variables across 21 sites. Across our sites, larger trees tended to have the highest disease incidence, and trees on shallow slopes had the most crown dieback. We then quantified genetic diversity and gene flow, and found that genetic structure has not been substantially impacted by habitat fragmentation, although dispersal typically covers short distances. However, genetic diversity is relatively low in smaller populations and in younger trees. Localized dispersal and eroding genetic diversity may limit future adaptation and hence exacerbate population declines. We recommend that managers prioritize plantings in small populations, avoid shallow slopes, and track younger trees to evaluate age-related mortality. Key words: Cornus florida, eastern flowering dogwood, Discula destructiva, fungal pathogens, forest fragmentation, gene flow, genetic diversity, Introduction Forests are the dominant terrestrial ecosystem on Earth (Pan et al. 2013), covering approximately 31% of the Earth's surface, and containing over 50% of terrestrial biodiversity (Aravanopoulos 2016; FAO [...]

Population structure and phylogeography of the loggerhead sea turtle (Caretta caretta) have so far been assessed mainly by mitochondrial DNA (mtDNA) single-gene sequencing studies. However, phylogenetic relationships amongst matrilines, genetic characterisation of rookeries and mixed-stock analyses have suffered from the limited resolution obtained by comparison of relatively short sequences such as from the mtDNA control region. Whole mitogenome sequencing can significantly improve population genetics, particularly in marine organisms showing female natal philopatry. Despite mitogenomics becoming increasingly common in biodiversity monitoring and conservation, only a few complete mitogenomes are available for C. caretta. In this study, we sequenced the complete mtDNA of 61 loggerhead turtles sampled between 2008 and 2021 along the Italian coastline and central Mediterranean Sea. We assigned complete mtDNA haplotypes to dead embryos and bycatch samples, and introduced a first nomenclature for loggerhead mitogenomes. Analysis of mtDNA diversity, Maximum Parsimony and Bayesian phylogenetic reconstruction allowed improved resolution of lineages with respect to studies reporting on partial mtDNA control region sequence comparisons, and we were able to further inform previous analyses on loggerhead ancestry based on control region haplogroups. Overall, whole mitogenome analysis has potential for considerable improvement of evolutionary history and phylogeographic investigations as well as mixed-stock surveys of loggerhead turtles., Author(s): Livia Tolve [sup.1] , Alessio Iannucci [sup.1] [sup.2] , Luisa Garofalo [sup.3] , Andrea Ninni [sup.4] [sup.5] , Andrea Capobianco Dondona [sup.6] , Ilaria Ceciarini [sup.7] , Cristiano Cocumelli [...]

Coastal marine ecosystems are highly productive and important for global fisheries. To mitigate over exploitation and to establish efficient conservation management plans for species of economic interest, it is necessary to identify the oceanographic barriers that condition divergence and gene flow between populations with those species, and that determine their relative amounts of genetic variability. Here, we present the first population genomic study of an Octopus species, Octopus insularis, which was described in 2008 and is distributed in coastal and oceanic island habitats in the tropical Atlantic Ocean. Using genomic data, we identify the South Equatorial current as the main barrier to gene flow between southern and northern parts of the range, followed by discontinuities in the habitat associated with depth. We find that genetic diversity of insular populations significantly decreases after colonization from the continental shelf, also reflecting low habitat availability. Using demographic modelling, we find signatures of a stronger population expansion for coastal relative to insular populations, consistent with estimated increases in habitat availability since the Last Glacial Maximum. The direction of gene flow is coincident with unidirectional currents and bidirectional eddies between otherwise isolated populations. Together, our results show that oceanic currents and habitat breaks are determinant in the diversification of coastal marine species where adults have a sedentary behavior but paralarvae are dispersed passively, shaping standing genetic variability within populations. Lower genetic diversity within insular populations implies that these are particularly vulnerable to current human exploitation and selective pressures, calling for the revision of their protection status., Author(s): Bernhard Bein [sup.1] [sup.2] [sup.3] [sup.4] , Françoise D. Lima [sup.5] [sup.6] , Henrique Lazzarotto [sup.7] , Luiz A. Rocha [sup.7] , Tatiana S. Leite [sup.8] , Sergio M. [...]

Assessing genetic differentiation among natural populations can aid understanding of dispersal patterns and connectivity among habitats. Several molecular markers have become increasingly popular in determining population genetic structure for this purpose. Here, we compared the resolution of mitochondrial cytochrome c oxidase subunit I (COI) and nuclear single nucleotide polymorphism (SNP) markers for detecting population structure among stream insects at small spatial scales. Individuals of three endemic taxa--Coloburiscus humeralis (Ephemeroptera), Zelandobius confusus (Plecoptera), and Hydropsyche fimbriata (Trichoptera)--were collected from forested streams that flow across open pasture in the North Island of New Zealand. Both COI and SNP data indicated limited population structure across the study area, and small differences observed among these species were likely related to their putative dispersal abilities. For example, fine-scale genetic differentiation between and among neighbouring stream populations for H. fimbriata suggests that gene flow, and hence dispersal, may be more limited for this species relative to the others. Based on the generally similar results provided by both types of markers, we suggest that either COI or SNP markers can provide suitable initial estimates of fine-scale population genetic differentiation in stream insects. Key words: dispersal, mtDNA, population structure, SNPs, stream insects Mesurer la differenciation genetique au sein de populations naturelles peut aider a comprendre leur dispersion et la connectivite entre habitats. Plusieurs marqueurs moleculaires sont devenus de plus en plus populaires pour determiner la structure genetique des populations pour ces fins. Dans ce travail, les auteurs ont compare la resolution de la structure des populations, parmi des insectes de ruisseaux a une echelle spatiale reduite, obtenue a l'aide de la sous-unite I de la cytochrome c oxydase (COI) mitochondriale et de marqueurs mononucleotidiques (SNP) nucleaires. Des individus de trois taxons endemiques--Coloburiscus humeralis (Ephemeroptera), Zelandobius confusus (Plecoptera) et Hydropsyche fimbriata (Trichoptera)--ont ete collectes dans des ruisseaux boises coulant au sein de prairies ouvertes de l'Ile du Nord de la Nouvelle-Zelande. Tant les donnees COI que SNP ont indique une faible structure des populations au sein de la zone etudiee, et les petites differences observees parmi ces especes etaient vraisemblablement dues a leur aptitude a la dispersion. Par exemple, une differenciation genetique a echelle fine entre et parmi les populations de ruisseaux voisins pour le H. fimbriata suggerait un flux genique ; ainsi, la dispersion est peut-etre plus limitee chez cette espece par rapport aux autres. Sur la base des resultats generalement semblables obtenus avec les deux types de marqueurs, les auteurs suggerent que les marqueurs COI ou SNP peuvent fournir des estimes initiaux valables de la differenciation genetique des populations a echelle reduite chez les insectes de ruisseaux. [Traduit par la Redaction] Mots-cles : dispersion, ADNmt, structure des populations, SNP, insectes de ruisseaux, Introduction Understanding how individuals move between populations across the landscape is an important component of the conservation and management of natural populations and their habitats (Alp et al. 2012; Weston [...]

The deep-sea precious red coral Hemicorallium laauense has long been overharvested in the North Pacific for the jewelry and curio trades. An understanding of the population structure and connectivity of these octocorals has been limited due to the difficulty of sampling and taxonomic challenges within the Family Coralliidae. We report on population genetics of 270 H. laauense individuals from 16 populations throughout the Main Hawaiian Islands (MHI) and the Northwestern Hawaiian Islands (NWHI) using nine microsatellite loci. Observed heterozygosity (0.69-0.85) was generally lower than expected heterozygosity (0.71-0.85) except for the population at Twin Banks. Moderate F.sub.IS values (0.01-0.20) were present in nearly half of the populations. Global G'.sub.ST (0.166) and pairwise values were moderate to high ( - 0.003 to 0.489). G'.sub.ST values also show moderate genetic structuring among populations within seamounts (0.12-0.22) for populations separated by as little as 3 km. DAPC indicated separation of the MHI from the NWHI, but two NWHI sites fall into the MHI clusters and samples from Ka'ena Point (an MHI site) appear to form their own cluster. Membership assignments showed moderate admixture between some locations, while three locations showed almost no admixture. Within-seamount admixture was surprisingly limited for populations on the same seamount. A pattern of isolation by distance, with exchange primarily among adjacent seamounts, was supported by MIGRATE results but not by Mantel tests. These results suggest a mixed pattern of connectivity, with some distant locations well connected and others more isolated. The inconsistent connectivity of these corals is likely amplified by their patchy distributions., Author(s): Nicole B. Morgan [sup.1] , Julia Andrews [sup.1] , Amy R. Baco [sup.1] Author Affiliations: (1) https://ror.org/05g3dte14, grid.255986.5, 0000 0004 0472 0419, Department of Earth, Ocean, and Atmospheric Science, [...]

Sesbania tomentosa (Fabaceae) is an endemic flowering plant primarily adapted to coastal strand and dry lowland habitat in the Hawaiian Islands. Previous studies have attempted to delineate distinct taxa from among the extant populations. In the most recent treatment of Hawaiian Fabaceae, however, S. tomentosa was recognized as a single polymorphic species with two forms. To readdress issues of taxonomy, the present study utilized microsatellite marker variation and DNA sequencing to discriminate Hawaiian Sesbania populations. While there was no DNA sequence variation among species for ITS or TRPT gene regions, microsatellite analysis found a highly differentiated population structure at the nine loci sampled. Bayesian genetic clustering assignments and associated private alleles occurred in a distinct phylogeographic pattern. As a result, three distinct genetic groups were identified corresponding to islands of origin: populations from Nihoa, Kaua'i, and O'ahu (group 1), populations from Maui, Kaho'olawe, and Moloka'i (group 2), and populations from Hawai'i Island (group 3). The extremely varied yet randomly overlapping morphologies among the populations suggest widespread convergent evolution has occurred and precludes any subspecific taxonomic designations. We interpret the high levels of genetic marker and morphologic differentiation exhibited by Hawaiian Sesbania to be a product of the plant's reproductive ecology and its influence in substructuring populations on a small geographic scale. Efforts toward preservation of the wide range of distinctive appearing morphotypes should continue, facilitated by the natural tendency of the plant to maintain a more or less fixed state of certain traits within populations. Keywords: biogeography, evolution, Fabaceae, Hawai'i, population genetics,, THE BOUNDARIES OF SPECIES that have recently and rapidly diverged are difficult to determine when species-specific traits have not had sufficient time to coalesce (Glor 2010). Even if the morphology [...]

As habitats change, species with higher intraspecific variation have more resources to adapt. Medicinal plants in the Himalayas are increasingly threatened by climate change and other anthropogenic influences. The intraspecific variation within and among 17 populations of the high-elevation herb Trillium govanianum Wall. ex D.Don was studied as an indicator of adaptability. The variation in 19 traits of population structure, morphology, and phytochemistry was assessed across habitats that varied in elevation (2452-3432 m a.s.1.), aspect, latitude (30.1-31.7[degrees]N), and arboreal community. The morphology and population structure were conserved among populations but varied among regions. The populations in the lower elevation mixed forests of Tirthan Valley produced smaller rhizomes but larger plant densities, such that plant biomass per square metre was conserved. The phytochemistry varied among regions and populations within regions, indicating significant variation among habitats. The aboveground morphology of the species masks considerable variations in belowground morphology and phytochemistry. The observed variations can help the species to adapt to the changing environmental conditions by provoking a functional response. Key words: adaptation, anthropogenic pressure, conservation, high-elevation medicinal plant, natural variations. Lorsque les habitats changent, les especes qui presentent une plus grande variation intraspecifique ont davantage de ressources pour s'adapter. Les plantes medicinales de l'Himalaya sont de plus en plus menacees par les changements climatiques et d'autres influences anthropiques. La variation intraspecifique au sein et entre 17 populations de Trillium govanianum Wall. ex D.Don, une herbe de haute altitude, a ete etudiee comme indicateur de l'adaptabilite. La variation de 19 traits de la structure de la population, de la morphologie et de la phytochimie a ete evaluee dans des habitats qui varient en matiere d'altitude (2452-3432 m a.s.1.), d'aspect, de latitude (30, 1 a 31, 7[degrees]N) et de peuplement frodicole. La morphologie et la structure de la population etaient conservees parmi les populations, mais elles variaient selon les regions. Les populations des forets mixtes de basse altitude de la vallee de Tirthan produisaient des rhizomes plus petits, mais des densites de plantes plus importantes, de sorte que la biomasse vegetale par [m.sup.2] etait conservee. La phytochimie variait entre les regions et les populations au sein des regions, indiquant une variation significative entre les habitats. La morphologie aerienne de l'espece masque des variations considerables dans la morphologie souterraine et la phytochimie. Les variations observees peuvent aider les especes a s'adapter aux conditions environnementales changeantes en provoquant une reponse fonctionnelle. [Traduit par la Redaction] Mots-cles : adaptation, pression anthropique, conservation, plante medicinale de haute altitude, variations naturelles., Introduction The rate at which species adapt to new or changing environments is dependent on their phenotypic plasticity and genetic variation (Fox et al. 2019). Species with a more flexible [...]

A.E. Morales et al. (2021. Can. J. Zool. 99(5): 415-422) provided no new evidence to alter the conclusions of C.L. Lausen et al. (2019. Can. J. Zool. 97(3): 267-279). We present background information, relevant comparisons, and clarification of analyses to further strengthen our conclusions. The genesis of the original 'evotis-keenii' study in British Columbia (Canada) was to differentiate Myotis keenii (Merriam, 1895) (Keen's myotis), with one of the smallest North American bat distributions, from sympatric Myotis evotis (H. Allen, 1864) (long-eared myotis), using something other than the suggested postmortem skull size comparison, but no differentiating trait could be found, leading to the molecular genetics examination of C.L. Lausen et al. (2019). We present cumulative data that rejects the 1979 hypothesis of M. keenii as a distinct species. A.E. Morales et al. (2021) inaccurately portray C.L. Lausen et al.'s (2019) question and results; present inaccurate morphological and outdated distribution data; overstate the impact of homoplasy without supporting evidence; and misinterpret evidence of population structure. Key words: Myotis evotis, long-eared myotis, Myotis keenii, Keen's myotis, bats, taxonomy, population genetics, Chiroptera, population structure. A.E. Morales et al. (2021. Can. J. Zool. 99(5): 415-422) ne fournissent aucune nouvelle preuve pouvant modifier les conclusions de C.L. Lausen et al. (2019. Can. J. Zool. 97(3): 267-279). Nous presentons des renseignements contextuels et des comparaisons pertinentes et apportons des precisions sur des analyses pour etoffer davantage nos conclusions. L'etude initiale sur la question<< evotis-keenii>> en Colombie-Britannique (Canada) visait a distinguer Myotis keenii (Merriam, 1895) (vespertilion de Keen), dont l'aire de repartition est l'une de plus petites en Amerique du Nord pour une chauve-souris, du taxon sympatrique Myotis evotis (H. Allen, 1864) (vespertilion a longues oreilles), en employant une autre approche que la comparaison post-mortem de la taille des cranes suggeree, mais aucun caractere distinctif n'avait ete releve, ce qui a mene a l'examen de C.L. Lausen et al. (2019) par des methodes de genetique moleculaire. Nous presentons des donnees cumulatives qui invalident l'hypothese de 1979 voulant que M. keenii soit une espece distincte. AE. Morales et al. (2021) proposent une caracterisation inexacte de la question et des resultats de C.L. Lausen et al. (2019), presentent des donnees morphologiques inexactes et des donnees de repartition obsoletes, accordent une trop grande importance a l'incidence de l'homoplasie sans preuve a l'appui et font une interpretation erronee de linformation touchant a la structure des populations. [Traduit par la Redaction] Mots-cles : Myotis evotis, vespertilion a longues oreilles, Myotis keenii, vespertilion de Keen, chauves-souris, taxonomie, genetique des populations, chiropteres, structure des populations., Introduction The study by Lausen et al. (2019) began out of conservation concern over the inability to differentiate Myotis evotis (H. Allen, 1864) (long-eared myotis) and Myotis keenii (Merriam, 1895) [...]

Genetic exchange and hybridization appear common among the western long-eared bats from North America. Multiple sources of evidence indicate that lineages within this group are evolving independently, despite genetic exchange. However, evidence of gene flow raises questions about the species-level status of some lineages. C.L. Lausen et al. (2019. Can. J. Zool. 97(3): 267-279) proposed that Myotis evotis (H. Allen, 1864) (long-eared myotis) and Myotis keenii (Merriam, 1895) (Keen's myotis) are one species, not two. This conclusion is based on analyses of cytochrome b and microsatellite data suggesting gene flow between these taxa. Microsatellites are not reliable markers for identifying species because homoplasy can be a major confounding factor, which appears to be true in this case. We reanalyzed the dataset of C.L. Lausen et al. (2019) and show that it is not reliable to distinguish between gene flow or homoplasy, and that these data do not support the conclusion that M. evotis and M. keenii represent a single species. Previous morphological and genomic studies indicate that these are separate species despite previous genetic exchange between them. Failing to recognize that gene flow can occur between independently evolving lineages is counterproductive for conservation because it can lead to neglect of important independent lineages, and likewise failing to use proper tools to delimit species is counterproductive to efforts to quantify biodiversity and design conservation strategies. Key words: bats, species, Myotis evotis, long-eared myotis, Myotis keenii, Keen's myotis, conservation, taxonomy, microsatellites. L'echange genetique et l'hybridation semblent repandus chez les vespertilions a longues oreilles de l'ouest de l'Amerique du Nord. De multiples elements de preuve indiquent que des lignees au sein de ce groupe evoluent de maniere independante, malgre la presence d'echanges genetiques. Des indices d'un flux genetique soulevent toutefois des questions quant au statut d'espece de certaines lignees. C.L. Lausen et al. (2019. Can. J. Zool. 97(3): 267-279) proposent que Myotis evotis (H. Allen, 1864) (vespertilion a longues oreilles) et Myotis keenii (Merriam, 1895) (vespertilion de Keen) representent une seule espece, et non deux. Cette conclusion repose sur des analyses du cytochrome b et de donnees de microsatellites qui indiqueraient un flux genetique entre ces deux taxons. Les microsatellites ne sont pas des marqueurs fiables pour l'identification d'especes puisque l'homoplasie peut constituer un important facteur de confusion, ce qui semble etre le cas dans le present exemple. Nous avons reanalyse l'ensemble de donnees de C.L. Lausen et al. (2019) et demontrons qu'il ne peut pas servir a distinguer de maniere fiable le flux genetique de l'homoplasie et que ces donnees n'appuient pas la conclusion que M. evotis et M. keenii representent une seule et meme espece. Des etudes morphologiques et genomiques passees indiquent qu'il s'agit d'especes distinctes, malgre des echanges genetiques passes entre elles. Le defaut de reconnaitre qu'un flux genetique peut se produire entre des lignees qui evoluent de maniere independante est contreproductif sur le plan de la conservation parce que d'importantes lignees independantes peuvent ainsi ne pas etre prises en consideration, et le fait de ne pas utiliser les bons outils pour delimiter des especes est egalement contreproductif pour ce qui est de quantifier la biodiversite et de concevoir de strategies de conservation. [Traduit par la Redaction] Mots-cles : chauves-souris, especes, Myotis evotis, vespertilion a longues oreilles, Myotis keenii, vespertilion de Keen, conservation, taxonomie, microsatellites., Introduction Bats are one of the most diverse orders of mammals with more than 1400 living species (Simmons and Cirranello 2019). But how are these species delimited? Species delimitation is [...]

The Mediterranean green turtle regional management unit is one of the 17 management units of green turtles considered a global conservation priority. However, previous studies using different genetic markers revealed very little diversity and differentiation across populations due to the overdominance of one haplotype (CM-A13) in the Mediterranean. We, therefore, used a more informative marker, mitochondrial short tandem repeats (mtSTRs), in 431 samples collected along the eastern Mediterranean coasts of Turkey and Northern Cyprus. In addition, we added the mtSTR haplotypes of previous studies and reached a total of 980 samples covering 12 nesting beaches (almost 100% of the populations in the region). We identified 42 haplotypes, 4 of which were recorded for the first time in the region. The species has a genetic diversity in the region higher than previously thought, ranging from 0.54 (Sugözü, Turkey) to 0.934 (Israel) and with the most common haplotypes being 6-8-8-4 (26.5%), 6-8-5-4 (17.3%), and 6-8-6-4 (14.9%). The analysis of a more extensive data set of mtSTRs supported recognizing at least three management units in the Mediterranean. Furthermore, we used the new data to assess the origin of the turtles foraging in Israel. We determined that Samandag (Turkey) was the population of origin of most of the individuals. Overall, we show that mtSTRs highly improve the resolution to detect population structuring and source for this species and region., Author(s): Sezgin Karaman [sup.1] , Oguz Turkozan [sup.1] , Carlos Carreras [sup.2] , Can Yilmaz [sup.3] , Bektas Sönmez [sup.4] , Onur Candan [sup.5] , Serap Ergene [sup.6] , Mahmut [...]

Fishes are among the most threatened taxa in Canada with over 70 species, subspecies, and (or) designatable units presently listed for protection under the Species at Risk Act (SARA). Protecting these species requires a diverse set of strategies based on the best-available data and information. One approach identified under SARA and in Canadian federal recovery strategies for improving the status of SARA-listed fishes is species reintroduction, which involves the release of individuals into areas from which they have been extirpated with the goal of re-establishing self-sustaining populations. The success of reintroduction relies on a comprehensive understanding of species ecology and life history, with considerations around population genetics and genomics. However, SARA-listed species are some of the most poorly known species in Canada due to their rarity and relative lack of research investment prior to the enactment of SARA. As a result, SARA-listed species have the most to lose if reintroduction activities are not carefully researched, planned, and executed. Therefore, the purpose of this review is to present an accessible summary on the state of reintroduction science for SARA-listed fishes in Canada with the hope of motivating future research to support reintroduction activities. We focus our review on 14 SARA-listed freshwater or anadromous identified as candidates for reintroduction in federal recovery strategies. We follow the species-specific summaries with guidance on how basic research questions in population ecology, habitat science, and threat science provide a critical foundation for addressing knowledge gaps in reintroduction science. Subsequently, we identify the importance of genetic and genomic techniques for informing future research on the reintroduction of SARA-listed species. We conclude with recommendations for active, experimental approaches for moving reintroduction efforts forward to recover Canadian fishes. Key words: Canada, conservation, endangered, freshwater fish, species at risk. Les poissons comptent parmi les taxons les plus menaces au Canada, avec plus de 70 especes, sous-especes et/ou unites designables actuellement inscrites a la liste des especes a proteger en vertu de la Loi sur les especes en peril (LEP). La protection de ces especes necessite un ensemble diversifie de strategies etabli en fonction des meilleures donnees et informations disponibles. La reintroduction d'especes est une approche definie dans la LEP et dans les programmes de retablissement federaux canadiens pour ameliorer la situation des poissons inscrits a la LEP, ce qui implique l'introductions d'individus dans des zones d'ou ils ont ete extirpes dans le but de retablir des populations capables de s'autoperpetuer. Le succes de la reintroduction repose sur une comprehension globale de l'ecologie des especes et de l'evolution biologique, avec des considerations relatives a la genetique et a la genomique des populations. Toutefois, les especes inscrites sur la liste de la LEP figurent parmi les especes les moins connues au Canada en raison de leur rarete et du manque relatif d'investissements en recherche avant l'adoption de la LEP. Ainsi, les especes inscrites a la LEP ont le plus a perdre si les activites de reintroduction ne sont pas soigneusement etudiees, planifiees et mises en oeuvre. Par consequent, le present document vise a presenter un resume accessible de l'etat de la science de la reintroduction des poissons inscrits a la LEP au Canada dans l'espoir de motiver les recherches futures a l'appui des activites de reintroduction. Notre examen porte sur 14 poissons d'eau douce ou anadromes inscrits sur la liste de la LEP consideres comme des candidats pour la reintroduction dans les programmes federaux de retablissement. Nous suivons les resumes specifiques de ces especes avec des conseils sur la facon dont les questions de recherche fondamentale sur l'ecologie des populations, la science des habitats et la science des menaces fournissent une base essentielle pour combler les lacunes dans les connaissances scientifiques sur la reintroduction. Par la suite, nous avons cerne l'importance des techniques genetiques et genomiques afin d'eclairer les futures recherches futures sur la reintroduction des especes inscrites a la LEP. Nous concluons en recommandant des approches actives et experimentales pour faire avancer les efforts de reintroduction afin de retablir les poissons canadiens. [Traduit par la Redaction] Mots-cles: Canada, conservation, en voie de disparition, poissons d'eau douce, especes en peril., Introduction Anthropogenic stressors such as habitat alteration, invasive species, and other landscape stressors, combined with changing thermal conditions due to climate change, are transforming global fish species distributions (Comte et [...]

Introduction Variation in genome size, i.e., variation in the DNA-content of cell nuclei, is a commonly observed phenomenon in plants (Bennett and Leitch 1995, 2011) and is generated by three [...], Variation in genome size and in chromosome number can be linked to genetic, morphological, and ecological characteristics, and thus be taxonomically significant. We screened the relative genome size (RGS) and counted the number of mitotic chromosomes in the African agroforestry tree Parkia biglobosa, a widely distributed savannah species that shows conspicuous morphological clinal variation and strong genetic structure, and tested for linkage of RGS variation to geography, leaf morphology, and population genetic variation. An improved protocol for the preparation of chromosomes was developed. The study is based on 58 individuals from 15 populations covering most of the distribution range of the species. We observed differences in RGS among individuals of up to 10.2%, with some of the individuals differing statistically in RGS from the bulk of screened individuals. Most of the RGS variation was within populations, whereas variation was unrelated to any of the tested features of the species. Those chromosome numbers that could be exactly established were invariable 2n = 2x = 26. In conclusion, there was no evidence from the karyological data for structured intraspecific taxonomic heterogeneity. Keywords: genome size, chromosome number, forestry, morphometry, population genetics. La variation quant a la taille du genome et au nombre de chromosomes peut etre liee a des caracteristiques genetiques, morphologiques et ecologiques, et peut donc s&apos;averer utile en taxonomie. Les auteurs ont estime la taille relative du genome (RGS) et compte le nombre de chromosomes mitotiques chez le Parkia biglobosa, un arbre utilise en agroforesterie et largement distribue dans la savane; celui-ci presente une variation morphologique evidente qui suit un gradient ainsi qu&apos;une structure genetique affirmee. Les auteurs ont egalement verifie l&apos;association entre la variation pour le RGS et la geographie, la morphologie foliaire et la variation genetique au sein des populations. Un protocole ameliore pour la preparation des chromosomes a ete mis au point. Cette etude a porte sur 58 individus provenant de 15 populations couvrant la majorite de l&apos;aire de distribution de cette espece. Les auteurs ont observe des differences en matiere de RGS pouvant atteindre 10,2 % entre les individus, certains individus presentant un RGS significativement different de la majorite des individus examines. La plus grande partie de la variation pour le RGS existait au sein des populations tandis que cette variation n&apos;etait associee a aucun des caracteres etudies. Le nombre de chromosomes, etabli de maniere exacte, etait invariable a 2n = 2x = 26. En conclusion, aucune evidence d&apos;une heterogeneite taxonomique intra-specifique n&apos;a ete prouvee a partir des analyses caryologiques. [Traduit par la Redaction] Mots-cles : taille du genome, nombre de chromosomes, foresterie, morphometrie, genetique des populations.

Introduction European hazelnut (common hazel, European filbert, Corylus avellana L.) is a diploid (2n = 2x = 22), monoecious, dichogamous, wind-pollinated shrub or small tree. It is strictly cross-pollinated due [...], European hazelnut (Corylus avellana L.) is a strictly cross-pollinated diploid tree species, which has its northernmost populations in Fennoscandia, and it was one of the first species to recolonize northern Europe after the last ice age. Hazelnut produces edible nuts in Finland but nowadays they are underutilized as food, and currently no breeding programmes exist. In the present study, 300 hazelnut specimens were collected from 20 different locations (= populations) in Finland, and they were genetically analyzed using nine simple sequence repeat (SSR) markers. Most of the genetic diversity existed within populations (83%). According to different genetic analyses (STRUCTURE, principal coordinates analysis, and clustering), a general lack of structure was observed, suggesting extensive gene flow among hazelnuts between 17 investigated populations. However, genetic structuring was clearly observed in three populations: Hakavuori, Mustiala, and Pahkinamaki, which might have become isolated due to geographical barriers that kept them separate, diminishing gene flow from other populations. Studying the diversity of European hazelnut is of great interest for understanding population genetics of a species distributed in its marginal areas in the north, and the results are also valuable for further uses in plant conservation, selection, and possible future breeding actions in Finland. Key words: Corylus avellana, gene flow, genetic structure, microsatellite, simple sequence repeat. Le noisetier commun (Corylus avellana L.) est un arbre diploïde à allofécondation stricte dont les populations les plus septentrionales sont situées en Finnoscandie et il a été parmi les premières espèces à recoloniser le nord de l&apos;Europe après la dernière ère glaciaire. Le noisetier produit des noix comestibles en Finlande, mais celles-ci sont sous-utilisées comme aliment et aucun programme de sélection n&apos;existe. Dans le présent travail, 300 spécimens de noisetiers ont été échantillonnés à 20 sites (= populations) en Finlande et ils ont été caractérisés génétiquement à l&apos;aide de neuf marqueurs microsatellites (SSR). La majorité de la diversité génétique se trouvait au sein des populations (83%). Suite à diverses analyses (STRUCTURE, analyse en coordonnées principales, partitionnement), aucune structure marquée n&apos;a été observée ce qui suggère des flux géniques importants entre les noisetiers des 17 populations étudiées. Cependant, une structure génétique nette a été observée au sein de trois populations : Hakavuori, Mustiala et Pähkinämäki, lesquelles seraient peut-être devenues isolées en raison, par exemple, de barrières géographiques qui auraient limité le flux génique en provenance des autres populations et les auraient maintenues séparées. L&apos;étude de la diversité génétique au sein du noisetier commun est d&apos;un grand intérêt pour mieux connaître la génétique des populations d&apos;une espèce située dans des aires septentrionales marginales. Les résultats sont également d&apos;intérêt pour d&apos;autres fins en lien avec la conservation, la sélection et de futurs efforts d&apos;amélioration génétique en Finlande. [Traduit par la Rédaction] Mots-clés : Corylus avellana, flux génique, structure génétique, microsatellite, séquence simple répétée.

ABSTRACT The Atlantic blue crab [Callinectes sapidus (Rathbun, 1896)] is a commercially and recreationally important decapod crustacean found in estuarine and nearshore waters of the western Atlantic. Recent declines in [...]

Most of the reef-building Acropora corals around Okinawa Island spawn in May and/or June. We found that two morphotypes of Acropora divaricata spawned in August and/or September. The 'robust' and 'slender' morphotypes differed in branch width and in the diameter of axial corallites. Histological analyses showed that the onset of gamete production/maturation occurred from June onwards. Most of the other Acropora species spawned from late May to early June. A. florida, which spawned in May/June, initiated gamete production in early April. We assumed that the two morphotypes of A. divaricata were reproductively isolated from most of the other Acropora species because of differences in the spawning seasons. We found that the spawning seasons of the two morphotypes slightly overlapped in 2015 but not in 2019, and inter-morphotype gamete compatibility was high. However, population genetics analyses and a phylogeny of the mitochondrial d-loop region showed that they were genetically distinct and rarely hybridized. Thus, the broadcast-spawning coral A. divaricata might have speciated when there might have been only a low possibility of interspecific gamete interaction., Author(s): Mao Furukawa [sup.1], Shun Ohki [sup.1], Seiya Kitanobo [sup.1], Hironobu Fukami [sup.2], Masaya Morita [sup.1] Author Affiliations: (1) grid.267625.2, 0000 0001 0685 5104, Sesoko Station, Tropical Biosphere Research Center, [...]