The Canadian Field-Naturalist (E-Journal)
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A late Pleistocene Wood Turtle (Glyptemys insculpta) from Iowa, USA: response of the taxon to glaciation and formation of the current range
Full text linkThe partial shell of a Wood Turtle (Glyptemys insculpta) was collected from the West Branch of the East Nishnabotna River in southwestern Iowa, near Malvern. By direct accelerator mass spectrometry, it radiocarbon dates to the late Pleistocene (10 220 ± 30 years before present [BP], 11 975–11 813 calibrated years [cal] BP). Other subfossil evidence indicates that Wood Turtles moved far south of their current range, into the southeastern United States, in response to late Pleistocene glaciation. The specimen suggests that the species also moved south and west, into a previously undocumented western range, where favourable habitat and, in particular, somewhat cooler summer temperatures prevailed until ~10 200 cal BP. My assessment of the Holocene subfossil record suggests that establishment of the western portion of the current range may have occurred within the past 1000 years. Phylogenetic analysis and direct radiometric dating of subfossil specimens are needed to determine additional details about the late Pleistocene dispersal of Wood Turtle and the postglacial formation of their current range.La carapace partielle de la tortue des bois (Glyptemys insculpta) a été collectée de la Rivière Nishnabotna Ouest au sud-ouest de l’Iowa. Sa datation radiocarbone par AMS remonte au Pléistocène tardif (10,220 ± 30 B.P., 11,975-11,813 cal B.P.). Une autre évidence subfossile montre que la tortue des bois s’est déplacée loin au sud de son aire de répartition actuelle, suite à la période glaciaire du Pléistocène tardif. Le spécimen montre que la tortue s’est aussi déplacée au sud et à l’ouest, dans une aire de répartition occidentale inconnue auparavant, où un habitat favorable et, en particulier, des températures estivales un peu plus fraîches prédominaient jusqu’à environ 10,200 cal B.P. (Avant le présent). L'évaluation du registre subfossile de l'Holocène suggère que l'établissement de la partie ouest de l'aire de répartition actuelle s'est produit au cours des mille dernières années. L'analyse phylogénétique et la datation radiométrique directe des spécimens subfossiles sont nécessaires pour éclairer des détails supplémentaires sur la dispersion de la tortue des bois pendant le Pléistocène tardif et la formation postglaciaire de leur aire de répartition actuelle
Territorial scent-marking and proestrus in a recolonizing wild Gray Wolf (Canis lupus) population in central Wisconsin
Full text linkGray Wolf (Canis lupus) uses scent-marking to communicate breeding status, dominance, and territorial boundaries. Despite its importance for reproduction and pack dynamics, information on scent-marking and proestrus in wild wolf populations is limited to a handful of locations. We estimated the rate of territorial scent-marking and the probability of proestrus in a recolonizing Gray Wolf population near the species southern range extent in eastern North America. An analysis of 221 pack-winters of tracking data show that the incremental addition of one wolf pack increased marking rates by 3.4%, whereas increasing the number of wolves in a pack decreased marking rates by 12.1%. Scent-marking rates subsequently increased from 1.9 times/km during recolonization to 3.0 times/km once the population was saturated. We observed evidence of proestrus from 19 December to 14 March with the highest probability of proestrus occurring around 6 February, after peak marking rates around 26 January. Repeated observations of bloody urinations within individual packs suggest proestrus averages 27.9 days. Our study reveals the role of population growth on territorial behaviours and provides a foundation for studies exploring the role of geographic and temporal variation on territorial and reproductive behaviours in wolves
Combining current and historical biodiversity surveys reveals order of magnitude greater richness in a British Columbia marine protected area
Full text linkThe value of biodiversity and of documented biodiversity surveys is well established. Extracting historical biodiversity data and synthesizing them with current data can provide a more comprehensive estimate of total diversity and guide future monitoring. We demonstrate the utility of compiling historical and recent biodiversity data to better characterize taxon richness and composition. Our focus is an otherwise unmonitored habitat in an unmonitored British Columbia provincial park, in a heavily impacted region of the Salish Sea that was designated a United Nation Biosphere Reserve in 2021. We conducted surveys and compiled historical records that together spanned three intertidal habitats and 43 years. From these combined data we report a total of 99 taxa, an order of magnitude increase over the number listed in the park’s Master Plan. These include seven non-native species, of which four are newly reported here. Rarefaction, extrapolation, and multivariate dissimilarity analyses revealed the roles of methods and habitat types in contributing to differences in taxon richness and composition among surveys. This data compilation illustrates many of the challenges and opportunities in aligning and assembling independent space-time snapshots of alpha (i.e., local) diversity to better understand the gamma (i.e., regional) diversity of a marine protected area and provides the foundational data needed to design effective future monitoring at molecular to ecosystem scales.We will be glad to provide a French-lanugage abstract on acceptance
Natural and human-made nesting habitat use by Bank Swallow (Riparia riparia) in Canada
Full text linkBank Swallow (Riparia riparia) is a Threatened migratory bird in Canada that nests colonially in burrows excavated in both human-made and natural banks. Until the mid-20th century, nest record cards reported 60% of Bank Swallows in Canada nested in human-made habitats. Here we provide an update on the proportion of Bank Swallow nesting colonies in natural and human-made habitats in Canada’s provinces and territories based on data from a variety of sources including breeding bird atlases and eBird. Bank Swallow nesting colonies reported from 2001 to 2017 throughout Canada indicate a reversal in the dominant type of habitat used for nesting, with a 56% probability that nesting occurrences are now found in natural habitats. We discuss possible mechanisms responsible for the apparent reversal and recommend that natural nesting habitat be formally protected and restored where it has been altered, especially where co-benefits include climate change resiliency. With the support of landowners and industry, active colonies in human-made habitats will likely make an important contribution to a resilient Bank Swallow population, the majority of which presently appears to nest in natural habitats across the country
Effets estimés des coupes à blanc et des brûlis sur l'utilisation de l'habitat par la femelle du caribou des bois: Effets des coupes à blanc et des brûlures sur le caribou
No full textThe decline of Caribou (Rangifer tarandus) is mainly attributed to anthropogenic disturbance from resource development (i.e., logging, oil and gas extraction), which causes habitat loss and increased predation risk. Natural landscape disturbance, particularly from fire, can have similar effects, and cumulative effects from disturbance have been associated with lower neonate recruitment. Our objective was to evaluate the potential effects of land cover types on resource selection by females, with an emphasis on clear-cuts and fire, during the calving season (May–June) in three neighbouring herds (Middle Ridge, Gaff Topsails, and Pot Hill) on insular Newfoundland, Canada, and compare results with pre-existing information on calf recruitment. We applied a resource selection framework to analyze location data collected from global positioning system collars between 2007–2010 and estimate relative probability of use for different cover types. Recruitment was lowest in Pot Hill, where ≤10-year old clear-cuts were favoured, whereas recruitment was highest in Middle Ridge and Gaff Topsails, where females favoured burns, suggesting that burns could be more beneficial to Caribou fitness. Further investigation will be needed to more closely examine how anthropogenic versus natural disturbance affects Caribou fitness in Newfoundland and improve our understanding of important habitat for calving females.Le déclin du caribou des bois (Rangifer tarandus caribou) est principalement attribué aux perturbations anthropiques dues à l'exploitation des ressources (c.-à-d. L'exploitation forestière, l'extraction de pétrole et de gaz), qui entraîne une perte d'habitat et un risque accru de prédation. Les perturbations naturelles du paysage, en particulier les incendies, peuvent avoir des effets similaires, et les effets cumulatifs des perturbations ont été associés à un recrutement plus faible des nouveau-nés. Notre objectif était d'évaluer les effets des types de couverture terrestre sur la sélection des ressources par les femelles, en mettant l'accent sur les coupes à blanc et le feu, pendant la saison de vêlage (mai-juin) dans 3 troupeaux voisins (Middle Ridge, Gaff Topsails et Pot Hill) à Terre-Neuve, au Canada, et comparez les résultats avec les informations préexistantes sur le recrutement des veaux. Nous avons appliqué un cadre de sélection des ressources pour analyser les données de localisation collectées à partir des colliers du système de positionnement mondial entre 2007 et 2010 et estimer les effets apparents des types de couverture terrestre sur l'utilisation relative. Le recrutement était le plus bas à Pot Hill, où la coupe à blanc de moins de 10 ans était favorisée, tandis que le recrutement était le plus élevé à Middle Ridge et à Gaff Topsails, où les femelles préféraient les brûlures, ce qui suggère que ce type de couverture terrestre pourrait être plus bénéfique pour la forme physique du caribou. Une étude plus approfondie sera nécessaire pour examiner de plus près comment les perturbations anthropiques par rapport aux perturbations naturelles affectent la condition physique du caribou à Terre-Neuve et améliorer notre compréhension de l'habitat important pour les femelles de mise bas
Red-eared Slider (Trachemys scripta elegans) nests in the Greater Toronto Area
Full text linkRed-eared Slider (Trachemys scripta elegans) is a non-native turtle found in abundance in Toronto’s wetlands as a result of pet releases. Although this species is known to reproduce successfully in southwestern Ontario, Canada, there is yet no evidence to suggest successful reproduction in the Greater Toronto Area (GTA). As part of a native turtle nest protection program, volunteers inadvertently placed nest protector boxes over four slider nests in 2021 and 10 nests in 2022. This gave us the opportunity to determine whether nests produced viable offspring and whether these hatchlings would emerge in the fall. The exact nesting date for each nest was recorded. In 2021, eight of the 41 eggs from the slider nests showed very late-stage arrested embryonic development. In 2022, one of the nests had four hatchlings out of their eggshells but still inside the nest cavity. It is unclear whether the hatchlings would emerge later in the fall or overwinter in the nest cavity and emerge the following spring. If the small population sampled accurately reflects what occurs in the GTA, complete egg development may be possible for this species in some years, in some locations, with the right local micro-climate and micro-habitat. We discuss implications for turtle nest protection in Toronto
