The Canadian Field-Naturalist (E-Journal)
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Probable predation by an American Black Bear (Ursus americanus) on a Gray Wolf (Canis lupus) pup in northwestern Wisconsin
No full textOn 13 June 2023, we noted probable predation by an American Black Bear (Ursus americanus) on a male Gray Wolf (Canislupus) pup in pine barrens of northern Bayfield County, Wisconsin. The wolf pup, which had been captured and radiocollared on 11 May 2023, was detected by mortality signal on 8 June 2023. Predation by black bears has previously been reported on Eastern Wolf (Canis lycaon), but our observation represents the first documentation of probable predation on Gray Wolves of which we are aware
A The history of commercial freshwater mussel harvest in southern Ontario: a short-lived fishery with long-lasting consequences
No full textFreshwater mussels (Bivalvia: Unionidae) have long been an important aquatic resource for humans, and North America’sIndigenous nations have harvested them for over 10 000 years. European exploitation began in the latter half of the 19th century, initially focussing on the collection of pearls and later shifting to the manufacture of buttons at the onset of the 20th century. By 1911, Canadian pearl button factories operated in Windsor, Berlin (now Kitchener), and Trenton, Ontario, and, by 1921, Ontario shell was being exported to factories in the United States. The Canadian harvest did not last long and ended by the mid-1940s as resources dwindled because of overexploitation, pollution, and industrial shifts to other raw materials for buttons (e.g., plastics). Annual river-specific harvest ranged from ~ 66 to 110 tonnes with a maximum of 291 tonnes (~1.1–4.4 million animals) collected at Dunnville on the lower Grand River in 1915. Although detailed collection information is lacking, species such as Mucket (Actinonaias ligamentina), Threeridge (Amblema plicata), and Round Pigtoe (Pleurobema sintoxia, now listed federally as Endangered) were targetted, while Purple Wartyback (Cyclonaias tuberculata, also now Endangered) was discarded (i.e., killed). Commercial harvests typically targetted adults, because they provided the desired quantity and type of material, resulting in death. Recent studies have shown that this type of directed mortality can have the greatest impact on the long-term persistence of these populations and, although the specific impacts of the historical harvest cannot be determined, it is likely that these harvests contributed to the current state of imperilment of this fauna
"The Power of Trees: How Ancient Forests Can Save Us if We Let Them" by Peter Wohlleben, translated by Jane Billinghurst, 2023, and "The Future is Now: Solving the Climate Crisis with Today’s Technologies" by Bob McDonald, 2022 [book review]
No full textPlasticité squelettogénique chez une espèce d'amphibien en milieux anthropisés
No full textHabitat loss and landscape fragmentation are major causes of numerous amphibian population declines. Although logging activities have been related to serious effects on growth rate and size at metamorphosis in several species, less is known about skeletal developmental modifications associated with disturbed habitats. We studied the effects of forest canopy modifications caused by logging activities on the skeletal development of a pond-breeding anuran, Wood Frog (Lithobates sylvaticus). Biotic and abiotic factors were collected for 30 semi-permanent ponds located in three habitat categories (regenerated forest, along skidding trails, and logged areas). A sample of 58 cleared and double-stained tadpoles were analyzed to compare developmental trajectories among habitats. Water temperature and pond morphometric characteristics, which were correlated with logging-related habitat alteration, had a major impact on tadpole developmental differences among pond categories. Developmental plasticity was evident in both absolute and relative timing of chondrification and ossification between regenerated forest ponds and disturbed ponds (i.e., along skidding trails and in logged areas). Ossification and chondrification patterns had a different response to environmental factors. Notably, we observed the early onset of skeletogenesis in the disturbed ponds, which may result in deleterious effects on the fitness of post-metamorphosed juveniles
"Wildlife, Landscapes, and Geology: an Alberta and Saskatchewan Touring Guide" by Dale Leckie, 2024 [book review]
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