Wetlands and predation in boreal ecosystems play essential roles throughout the breeding season for bird assemblages. We found a positive association of beaver activity and a negative influence of American red squirrels (Tamiasciurus hudsonicus) on bird assemblages. We used a multispecies hierarchical model to investigate whether bird communities differ between two major wetland habitats in boreal Canada: beaver ponds and peatland ponds. In addition to including variables such as forest cover and latitude, we adopted a structural equation model approach to estimate the occupancy of American red squirrels and its potential influence on bird communities. Using automated recording stations deployed at 50 ponds, we detected 96 bird species in 2018 and 2019. Bird species were grouped into four taxonomic guilds according to their habitat successional requirements: early successional species, late successional species, generalists, and wetland species. Beaver ponds harbored higher species richness, a pattern driven primarily by early successional species. The occupancy of almost a quarter of the species was lower in the presence of red squirrels. Late successional species responded positively to the cover of forest surrounding the pond. Our results highlight the value of considering acoustic data of red squirrels to quantify habitat quality in boreal forests. We conclude that beaver activity shapes bird assemblages through modification of their habitat, and that some bird guilds are associated negatively with the presence of American red squirrels.

Les milieux humides et la prédation dans les écosystèmes boréaux jouent des rôles essentiels tout au long de la saison de reproduction pour les assemblages d’oiseaux. Nous avons trouvé une association positive entre les assemblages d’oiseaux et l’activité des castors, mais une association négative entre les assemblages d’oiseaux et la présence des écureuils roux d’Amérique (Tamiasciurus hudsonicus). Nous avons utilisé un modèle hiérarchique multi-espèces pour étudier si les communautés d’oiseaux diffèrent entre deux importants types de milieux humides du Canada boréal: les étangs de castors et les étangs de tourbières. Au-delà de l’inclusion de variables telles que le couvert forestier et la latitude, nous avons adopté une approche de modèle d’équation structurelle pour estimer l’occupation de l’écureuil roux d’Amérique et son influence potentielle sur les communautés d’oiseaux. En utilisant des stations d’enregistrement automatisées déployées sur 50 étangs, nous avons détecté 96 espèces d’oiseaux en 2018 et 2019. Les espèces des oiseaux ont été regroupées en quatre guildes taxonomiques en fonction de leurs exigences en matière de succession de l’habitat: espèces de début de succession, espèces de fin de succession, généralistes et espèces des milieux humides. Les étangs de castors abritaient une plus grande richesse d’espèces et une composition d’espèces différente de celle des étangs de tourbières, une tendance principalement liée aux espèces de début de succession. L’occupation de près d’un quart des espèces était plus faible en présence de l’écureuil roux. Les espèces de fin de succession ont répondu positivement à la couverture de la forêt entourant l’étang. Nos résultats soulignent l’intérêt de considérer les données acoustiques de l’écureuil roux pour quantifier la qualité de l’habitat dans les forêts boréales. Nous concluons que l’activité des castors façonne les assemblages d’oiseaux en modifiant leur habitat et que certaines guildes d’oiseaux sont associées négativement à la présence de l’écureuil roux d’Amérique.

Interspecific interactions can mediate site occupancy of sympatric species and can be a key factor in habitat use patterns. American martens (Martes americana) and Fishers (Pekania pennanti) are two sympatric mesocarnivores in eastern North American forests. Due to their larger size, fishers have a competitive advantage over martens. We investigated site occupancy of martens and fishers in temperate deciduous forests of Québec, an environment modified by forest management and climate change. We formulated hypotheses on the spatial distribution of the studied species based on the knowledge of local trappers and on the scientific literature regarding forest cover composition, habitat fragmentation, and competitive relationships. We used a network of 49 camera traps monitored over two fall seasons to document site occupancy by both species. We used two-species site occupancy models to assess habitat use and the influence of fishers on martens at spatial grains of different sizes. None of the habitat variables that we considered explained site occupancy by fishers. Availability of dense old coniferous stands explained the spatial distribution of martens both at the home range grain size and at the landscape grain size. We identified the characteristics of habitat hotspots based on the knowledge of trappers, which highlighted the importance of stand composition, height, age, and canopy closure. The characteristics of habitat hotspots for martens in temperate deciduous forests refine the habitat suitability model for American martens that was originally developed for boreal forests of Québec.

Wetlands are essential for many animal and plant species. However, many of these ecosystems are being degraded. Wetland degradation affects the habitat of certain groups of species such as waterfowl, which use these environments at different stages of their life cycle. In this study, we assessed the quality of man-made wetlands, i.e., mine tailing ponds, in comparison to beaver ponds, which are natural wetlands used by waterfowl. We conducted repeated surveys of breeding waterfowl species present on 12 mining ponds and 38 beaver ponds in boreal western Quebec, Canada. We also conducted brood surveys and considered environmental variables at the sites that could affect their occupancy. Conditions at the mining ponds appear to be as favorable for the establishment of breeding waterfowl as those observed in beaver ponds. Using site occupancy models, we found that five out of the six species studied were as likely to occupy and breed in mining ponds as in beaver ponds: Mallard (Anas platyrhynchos), Ring-necked Duck (Aythya collaris), American Wigeon (Mareca americana), Green-winged Teal (Anas crecca), and Hooded Merganser (Lophodytes cucullatus). Both adults and broods of Common Goldeneye (Bucephala clangula) were more likely to use mining ponds than beaver ponds, but we did not find a direct relationship between goldeneye occupancy and environmental variables at our sites. Overall, the results of our study suggest that mining ponds have the potential to be managed for waterfowl and used by this group during the breeding season. However, further studies are required to assess the long-term effects of mining ponds on wildlife, particularly regarding contaminants such as heavy metals likely present at such sites.

Ecosystem-based management aims to preserve old-growth forest attributes using techniques mimicking natural disturbances. One such technique is irregular shelterwood logging, but its impacts on forest floor organisms are poorly known. Our objective was to quantify the effects of three different treatments of irregular shelterwood on population structure and the body condition of the eastern red-backed salamander (Plethodon cinereus) 5–6 years following harvesting. A total of 64 sites in western Québec were sampled using artificial refugia and quadrat searches. Large salamanders (>32 mm) were more abundant in the gap treatment than in strip, uniform, or control treatments. Small salamanders (≤32 mm) followed the same pattern, although the differences were marginal. For a given treatment, small salamanders were as abundant as large salamanders. Salamander body condition differed between the 2 years of sampling but did not differ among treatments, regardless of salamander size. We conclude that environmental conditions in irregular shelterwood treatments 5–6 years following harvesting support populations of small vertebrates on the forest floor.

Citizen science (CS) currently refers to the participation of non-scientist volunteers in any discipline of conventional scientific research. Over the last two decades, nature-based CS has flourished due to innovative technology, novel devices, and widespread digital platforms used to collect and classify species occurrence data. For scientists, CS offers a low-cost approach of collecting species occurrence information at large spatial scales that otherwise would be prohibitively expensive. We examined the trends and gaps linked to the use of CS as a source of data for species distribution models (SDMs), in order to propose guidelines and highlight solutions. We conducted a quantitative literature review of 207 peer-reviewed articles to measure how the representation of different taxa, regions, and data types have changed in SDM publications since the 2010s. Our review shows that the number of papers using CS for SDMs has increased at approximately double the rate of the overall number of SDM papers. However, disparities in taxonomic and geographic coverage remain in studies using CS. Western Europe and North America were the regions with the most coverage (73%). Papers on birds (49%) and mammals (19.3%) outnumbered other taxa. Among invertebrates, flying insects including Lepidoptera, Odonata and Hymenoptera received the most attention. Discrepancies between research interest and availability of data were as especially important for amphibians, reptiles and fishes. Compared to studies on animal taxa, papers on plants using CS data remain rare. Although the aims and scope of papers are diverse, species conservation remained the central theme of SDM using CS data. We present examples of the use of CS and highlight recommendations to motivate further research, such as combining multiple data sources and promoting local and traditional knowledge. We hope our findings will strengthen citizen-researchers partnerships to better inform SDMs, especially for less-studied taxa and regions. Researchers stand to benefit from the large quantity of data available from CS sources to improve global predictions of species distributions.

The boreal forest is considered to be a low productivity forest due to its cold climate and poorly drained soils promoting paludification. These factors create conditions favouring accumulation of undecomposed organic matter, which causes declining growth rates of forest stands, ultimately converting mature stands into peatlands. Under these conditions, careful logging is conducted during winter, which minimizes soil disturbance in northwestern Quebec boreal forest. This results in water table rise, increased light availability and paludification. Our main objective was to evaluate the short-term effect of partial harvesting as an alternative method to careful logging in winter to mitigate water table rise on black spruce (Picea mariana [Mill.] B.S.P.) stands. We quantified tree stem diameter variation and daily variation in water table depth in mature spruce stands before and after partial harvest (basal area reduction of 40%) and girdling (same basal area reduction with delayed mortality) during 2016 and 2017 growing seasons. Water table variation prior to and following silvicultural treatments did not differ one year after treatment. Daily stem diameter variation in black spruce did not differ between treatments and control. Furthermore, temperature exerted a positive effect on variation in water table and on stem diameter. These results suggest that partial harvest could be more effective than clearcutting to mitigate negative effects of a high water table while limiting paludification.