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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 [...]

Abstract: Parasites use their hosts for nutrition, shelter, and even dispersal; the latter can result in sex-biased parasite distribution. Host sex-biased parasitism has been well documented in vertebrates, including mammals, [...]

The widespread occurrence of alternative reproductive tactics (ARTs) highlights the diverse ways in which sexual selection can operate within a population. We studied ARTs in Columbian ground squirrels (Urocitellus columbianus), evaluating paternity, lifetime reproductive success, and life histories. Reproductively mature male Columbian ground squirrels displayed either a territorial or satellite (nonterritorial) tactic. Territorial males secured a higher proportion of copulations, were more likely to mate at earlier positions in females' mating sequences, and sired more offspring than satellite males. The tactic males adopted were largely a function of weight, age, and experience, with larger, older, and more experienced males displaying the territorial tactic. At 2 years of age, males adopted the satellite tactic or deferred breeding for the season. Two-year-old satellite males were heavier than males that deferred breeding, but by age 3, there was no difference between their weights. Males that deferred breeding either adopted the satellite or territorial tactic in the following year, with the lighter males displaying the satellite tactic. The ARTs that males adopted at 2 and 3 years of age led to alternative life history pathways. Males that deferred breeding and only adopted the territorial tactic during their lifetime had twice the number of lifetime offspring compared with males that adopted the satellite tactic and then switched to territorial behavior in following years, although this difference was not statistically significant. Our findings show that the satellite tactic results in lower reproductive output both within a single year, except at age 2, and over their lifetime. [ABSTRACT FROM AUTHOR]

Enteric parasites can have wide-ranging effects throughout an ecosystem, often driving coevolutionary and ecological processes. Parasites have long been overlooked in conservation efforts because of the negative impact inflicted on their hosts; however, parasites make up a significant component of Earth's biodiversity and host conservation efforts need to be parasite inclusive. The Vancouver Island marmot (VIM), Marmota vancouverensis, is an endangered alpine rodent endemic to Vancouver Island, British Columbia, Canada. Captive-bred VIMs are released to augment the wild population, but their susceptibility to parasites is unknown. The objectives of this study were to describe the diversity, prevalence, severity, and temporal variation of VIM enteric parasites. Noninvasive fecal samples were collected from wild and captive marmots and analyzed using a modified McMaster fecal egg floatation technique to indicate parasite prevalence and relative mean abundance. We identified oocysts and ova from 3 parasite taxa including a protozoan coccidium not previously described in the VIM (prevalence 68%), an ascarid nematode Baylisascaris laevis (prevalence 82%), and an anoplocephalid cestode Diandrya vancouverensis (prevalence 8%). Depending on the species, comparisons revealed variation in parasite infection by sex, by colony, and between wild and captive VIMs, but not among age classes or by female reproductive status. Finally, captive VIMs displayed significant monthly variation in parasite prevalence and mean egg abundance, suggesting a seasonal influence on parasite egg shedding. This information is critically important for future research investigating the influences of these trends on the health, ecology, and conservation of VIMs and their parasites., (© American Society of Parasitologists 2024.)

The tendency of females to mate with multiple males is often explained by direct and indirect benefits that could outweigh the many potential costs of multiple mating. However, behaviour can only evolve in response to costs and benefits if there is sufficient genetic variation on which selection can act. We followed 108 mating chases of 85 North American red squirrels (Tamiasciurus hudsonicus) during 4 years, to measure each female's degree of multiple male mating (MMM), and used an animal model analysis of our multi-generational pedigree to provide what we believe is the first estimate of the heritability of MMM in the wild. Female red squirrels were highly polyandrous, mating with an average of 7.0 ± 0.2 males on their day of oestrus. Although we found evidence for moderate levels of additive genetic variation (CV(A) = 5.1), environmental variation was very high (CV(E) = 32.3), which resulted in a very low heritability estimate (h(2) < 0.01). So, while there is genetic variation in this trait, the large environmental variation suggests that any costs or benefits associated with differences among females in MMM are primarily owing to environmental and not genetic differences, which could constrain the evolutionary response to natural selection on this trait.