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Island biogeography can promote rapid diversification and speciation via geographic isolation and novel selection pressures. These same factors can threaten the persistence of island endemics by limiting gene flow and suitable habitat. Host-parasite interactions on islands introduce another dimension of complexity as both species must simultaneously adapt to exogenous and endogenous factors. One example of host-parasite island biogeography is the critically endangered Vancouver Island (VI) marmot (Marmota vancouverensis) which is endemic to VI, Canada, and hosts two enteric helminth parasites: Baylisascaris laevis, an ascarid nematode common in tribe Marmotini, and Diandrya vancouverensis, an anoplocephalid cestode endemic to the VI marmot. Here, we aligned novel sequences from B. laevis (six genes) and D. vancouverensis (two genes) with congeneric sequences from GenBank. Phylogenies reconstructed using Bayesian and maximum parsimony approaches consistently placed B. laevis in a morphoclade, and D. vancouverensis in a monophyletic clade sister to D. composita. Mean pairwise sequence divergence between D. vancouverensis and D. composita (9.06 ± 1.94%) surpassed commonly accepted thresholds for species delimitation, whereas divergence between VI and mainland populations of B. laevis (1.12 ± 0.78%) was comparable to (or sometimes greater than) pairwise divergence values between other Baylisascaris species. Disparity in the genetic divergence of each parasite may reflect differences in their life cycle, host specificity, virulence, and the chronological extent of their isolation. Detailed descriptions of the population genetic structure and effects of both parasites on their shared host are crucial next steps in understanding the history of B. laevis and D. vancouverensis on VI and informing conservation efforts for the VI marmot and its enteric helminth parasites.

The Peraia of Samothrace Project (HFRI-FM17-750) is a multi-disciplinary archaeological fieldwork project to investigate the diachronic settlement patterns from Prehistory to the Modern Era of the coastal and inland landscape opposite the island of Samothrace in the northern Aegean Sea. It uses integrated and non-invasive methods such as remote sensing, geophysical prospection, and intensive pedestrian field walking to explore the regional topography and the diversity of human occupation. One important aspect of the project addresses the question of Samothracian settlements mentioned in the written sources. This paper presents the results of the 2020–2021 fieldwork campaign, including the methodological framework of the survey, an overview of ancient literary sources and previous archaeological work in the region, and a preliminary report of the archaeological survey as well as a general discussion of the combined outcome of the results.

Orchids often have specific pollinators, which should provide reproductive isolation, yet many produce natural hybrids. Platanthera dilatata and P. stricta differ in floral morphology but often co-occur, overlap in flowering, and are reputed parents of P. xestesii. We used motion-triggered video detection units to monitor floral visitors of P. dilatata and P. stricta on Vancouver Island, Canada. Pollinia removal in P. dilatata was observed using histochemical staining, and cross-pollinations were performed to determine compatibility. From 1,152 h, 753 videos were recorded; 655 contained insects and 91 contained arachnids. Bumblebees, butterflies, and moths removed pollinia from P. dilatata. No pollinia removal was observed from P. stricta. Five videos showed insects moving between Platanthera species. Pollinia removal rates were low. Hand-pollinations resulted in capsule development and seed production. This study adds to the known diversity of insects interacting with these orchids, and highlights regional differences in floral visitors.

Abstract Background Our understanding of gut microbiota has been limited primarily to findings from human and laboratory animals, but what shapes the gut microbiota in nature remains largely unknown. To fill this gap, we conducted a comprehensive study of gut microbiota of a well-studied North American red squirrel (Tamiasciurus hudsonicus) population. Red squirrels are territorial, solitary, and live in a highly seasonal environment and therefore represent a very attractive system to study factors that drive the temporal and spatial dynamics of gut microbiota. Result For the first time, this study revealed significant spatial patterns of gut microbiota within a host population, suggesting limited dispersal could play a role in shaping and maintaining the structure of gut microbial communities. We also found a remarkable seasonal rhythm in red squirrel’s gut microbial composition manifested by a tradeoff between relative abundance of two genera Oscillospira and Corpococcus and clearly associated with seasonal variation in diet availability. Our results show that in nature, environmental factors exert a much stronger influence on gut microbiota than host-associated factors including age and sex. Despite strong environmental effects, we found clear evidence of individuality and maternal effects, but host genetics did not seem to be a significant driver of the gut microbial communities in red squirrels. Conclusion Taken together, the results of this study emphasize the importance of external ecological factors rather than host attributes in driving temporal and spatial patterns of gut microbiota in natural environment.

It is often assumed that the northern peripheral populations of species' ranges are genetically depauperate due in part to founder effects from postglacial colonization. The majority of federally protected plant species are peripheral in Canada, yet we have little information about their patterns of genetic diversity and structure. In British Columbia, the majority of these protected plant species occur in two threatened habitats: the Garry oak and Okanagan shrub-steppe ecosystems. Using universal noncoding chloroplast DNA markers, we investigated genetic diversity and genetic structure in four rare and common plant species pairs inhabiting these two ecosystems. We found that rare species had lower genetic diversity than their common congeners, and detected contrasting patterns of regional diversity and structure based on ecosystem. Species from the Garry oak ecosystem showed lower genetic diversity in the northern deglaciated region and significant differentiation between regions, likely due to limited dispersal between Vancouver Island and the mainland. Species from the Okanagan shrub-steppe, however, tended to have uniform diversity across their range and lack regional structure. This study provides an important first look at the phylogeographic patterns of four rare plant species in British Columbia. Key words: conservation genetics, British Columbia, rare plants, chloroplast DNA, phylogeography, genetic diversity, Garry oak ecosystem, shrub-steppe ecosystem, Introduction Genetic diversity is critical to the long-term viability of wild plant and animal species (Frankham 1996; Hughes et al. 2008) and is considered a prerequisite for adaptation to changing [...]

Mitochondrial DNA is commonly used in population genetic studies to investigate spatial structure, intraspecific variation, and phylogenetic relationships. The control region is the most rapidly evolving and largest non-coding region, but its analysis can be complicated by heteroplasmic signals of genome duplication in many mammals, including felids. Here, we describe the presence of heteroplasmy in the control region of Canada lynx (Lynx canadensis) through intra-individual sequence variation. Our results demonstrate multiple haplotypes of varying length in each lynx, resulting from different copy numbers of the repetitive sequence RS-2 and suggest possible heteroplasmic single nucleotide polymorphisms in both repetitive sequences RS-2 and RS-3. Intra-individual variation was only observed in the repetitive sequences while inter-individual variation was detected in the flanking regions outside of the repetitive sequences, indicating that heteroplasmic mutations are restricted to these repeat regions. Although each lynx displayed multiple haplotypes of varying length, we found the most common variant contained three complete copies of the RS-2 repeat unit, suggesting copy number is regulated by stabilizing selection. While genome duplication offers potential for increased diversity, heteroplasmy may lead to a selective advantage or detriment in the face of mitochondrial function and disease, which could have significant implications for wildlife populations experiencing decline (e.g., bottlenecks) as a result of habitat modification or climate change. [ABSTRACT FROM AUTHOR]

The Canadian Rocky Mountains are one of the few places on Earth where the spatial genetic structure of wide-ranging species has been relatively unaffected by anthropogenic disturbance. We characterized the spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis Shaw, 1804) in the northern portion of their range. Using microsatellites from 1495 individuals and mitochondrial DNA sequences from 188 individuals, we examined both broad- and fine-scale spatial genetic structure, assessed sex-biased gene flow within the northern portion of the species range, and identified geographic patterns of genetic diversity. We found that broad-scale spatial genetic structure was consistent with barriers to movement created by major river valleys. The fine-scale spatial genetic structure was characterized by a strong isolation-by-distance pattern, and analysis of neighborhood size using spatial autocorrelation indicated gene flow frequently occurred over distances of up to 100 km. However, analysis of sex-specific spatial autocorrelation and analysis of mitochondrial haplotype distributions failed to detect any evidence of sex-biased gene flow. Finally, our analyses reveal decreasing genetic diversity with increasing latitude, consistent with patterns of post-glacial recolonization of the Rocky Mountains. Key words: spatial genetic structure, post-glacial recolonization, ungulates, terrestrial, alpine, Rocky Mountain bighorn sheep, Ovis canadensis canadensis. Les montagnes Rocheuses canadiennes sont un des rares endroits sur terre ou la structure genetique spatiale d'especes a grande aire de repartition a ete assez peu touchee par des perturbations d'origine humaine. Nous avons caracterise la structure genetique spatiale du mouflon des montagnes Rocheuses (Ovis canadensis canadensis Shaw, 1804) dans lapartie nordde son aire de repartition. En utilisant des microsatellites de 1495 individus et des sequences d'ADN mitochondrial de 188 individus, nous avons examine la structure genetique spatiale a grande echelle et a echelle fine, evalue la presence de flux genetique biaise en fonction du sexe dans la partie nord de l'aire de repartition de l'espece et cerne des motifs de repartition geographique de la diversite genetique. Nous avons constate que la structure genetique spatiale a grande echelle reflete la presence d'obstacles aux deplacements crees par d'importantes vallees fluviales. La structure genetique spatiale a echelle fine est caracterisee par un motif marque d'isolement par la distance, et l'analyse de la taille des voisinages en utilisant l'autocorrelation spatiale indique qu'un flux genetique a frequemment lieu sur des distances pouvant atteindre 100 km. L'analyse de l'autocorrelation spatiale selon le sexe et l'analyse de la repartition des haplotypes mitochondriaux n'ont toutefois permis de deceler aucun indice de flux genetique biaise en fonction du sexe. Enfin, nos analyses revelent une diminution de la diversite genetique vers les plus hautes latitudes, ce qui concorde avec des motifs de recolonisation postglaciaire des montagnes Rocheuses. [Traduit par la Redaction] Mots-cles : structure genetique spatiale, recolonisation postglaciaire, ongules, terrestre, alpin, mouflon des montagnes Rocheuses, Ovis canadensis canadensis., Introduction In the absence of anthropogenic habitat fragmentation, the natural population genetic structure of species can be defined by natural geographic and ecological barriers (Slatkin 1985, 1987), or the dispersal [...]

Garry oak (Quercus garryana Douglas ex Hook.) is a deciduous tree whose ecosystem is listed 'at risk' throughout its range in British Columbia (BC), Canada, under the Canadian Species at Risk Act. Garry oak ecosystems host the most diverse flora for coastal BC, yet they account for less than 0.3% of the province's land coverage. Due to the loss and degradation of Garry oak habitat, many associated plant and animal species that rely on these sensitive ecosystems are endangered. Microsatellite markers were used to investigate temporal changes in fine-scale population genetic structure of 121 Garry oak trees from the Nanaimo region (Vancouver Island, BC) using diameter at breast height as a proxy for age. Overall, allelic diversity was moderate, ranging from 3.0 to 7.5 alleles per locus with a mean of 4.4 ([+ or -]0.4 SE) across all loci. Global fixation indices ([F.sub.ST]) of 0.06 and 0.09 suggest significant departures from Hardy-Weinberg equilibrium among all populations and age-classified subpopulations, respectively. We found no evidence for change in genetic diversity across generations. Our results indicate low levels of differentiation within populations and high levels of gene flow among populations, suggesting an adaptive potential for Garry oaks in response to future climate change events. Key words: diameter at breast height, Garry oak, genetic structure, microsatellites, Quercus garryana. Le chene de Garry (Quercus garryana Douglas ex Hook.) est un arbre decidu dont l'ecosysteme est identifie << a risque >> a travers toute son etendue en Colombie-Britannique (CB), Canada, selon la Loi sur les especes en peril du Canada. Les ecosystemes du chene de Garry abritent la flore la plus diversifiee de la cote de la CB, constituant maintenant moins de 0.3% de la couverture des terres de la province. A cause de la perte et de la degradation de l'habitat du chene de Garry, plusieurs especes vegetales et animales associees qui dependent de ces ecosystemes fragiles sont menacees. Des marqueurs microsatellites ont ete utilises pour examiner les changements temporels de la structure genetique d'une population a petite echelle de 121 chenes de Garry dans la region de Nanaimo (Ile de Vancouver, CB), utilisant le diametre a hauteur de poitrine pour estimer l'age de l'arbre. Globalement, la diversite allelique etait moderee, allant de 3,0 a 7,5 alleles par locus, avec une moyenne de 4,4 ([+ ou -] 0,4 ES) a travers tous les locus. Les indices de fixation globaux ([F.sub.ST]) de 0,06 et 0,09 suggerent des ecarts significatifs de l'equilibre de Hardy-Weinberg parmi toutes les populations et les sous-populations classees selon l'age, respectivement. Les auteurs n'ont trouve aucun indice d'un changement dans la diversite genetique a travers les generations. Leurs resultats indiquent de faibles niveaux de differenciation a l'interieur des populations et de hauts niveaux de flux geniques entre les populations, suggerant que le chene de Garry possede un potentiel adaptatif en reponse aux evenements lies aux changements climatiques futurs. [Traduit par la Redaction] Mots-cles: diametre a hauteur de poitrine, chene de Garry, structure genetique, microsatellites, Quercus garryana., Introduction Garry oak (Fagaceae: Quercus garryana Douglas ex Hook.) is the only native oak species found in British Columbia (BC), Canada. The current distribution of Garry oak ranges from the [...]

Ref.: Botany. 101(1): 1-14 (2023). https://doi.org/10.1139/cjb-2022-0064 In the originally published article, the author contributions were listed incorrectly. The corrected statement is below, and the original article is corrected. EJW and [...]

While climate warming is widely predicted to reduce body size of ectotherms, evidence for this trend is mixed. Body size depends not only on temperature but also on other factors, such as food quality and intraspecific competition. Because temperature trends or other long‐term environmental factors may affect population size and food sources, attributing trends in average body size to temperature requires the separation of potentially confounding effects. We evaluated trends in the body size of the midge Tanytarsus gracilentus and potential drivers (water temperature, population size, and food quality) between 1977 and 2015 at Lake Mývatn, Iceland. Although temperatures increased at Mývatn over this period, there was only a slight (non‐significant) decrease in midge adult body size, contrary to theoretical expectations. Using a state‐space model including multiple predictors, body size was negatively associated with both water temperature and midge population abundance, and it was positively associated with 13C enrichment of midges (an indicator of favorable food conditions). The magnitude of these effects were similar, such that simultaneous changes in temperature, abundance, and carbon stable isotopic signature could counteract each other in the long‐term body size trend. Our results illustrate how multiple factors, all of which could be influenced by global change, interact to affect average ectotherm body size. [ABSTRACT FROM AUTHOR]