Search Results (4)

Megafires are transforming western boreal forests, and many burned forests are salvage logged, removing more structure from landscapes and delaying forest regeneration. We studied forest-dwelling owls in a post-fire and salvage-logged landscape in central British Columbia, Canada, in 2018–2019 after the 2010 Meldrum Creek Fire and the 2017 Hanceville Fire. We examined owl habitat selection via call surveys compared to the habitats available in this landscape. Owl pellets were dissected to determine owl diets. We detected six owl species, of which Northern Saw-whet Owls (Aegolius acadicus) were the most common. Owls had weak and variable habitat selection within an 800 m radius of detections; all species used some burned area. Great Gray Owls (Strix nebulosa) and Great Horned Owls (Bubo virginanus) obtained more prey from mature forests (e.g., red-backed voles, Myodes gapperi, snowshoe hares, Lepus americanus) than other owls did, whereas other owls primarily consumed small mammals that were common in burned or salvaged areas. These results indicate a diverse community of owls can use landscapes within a decade after wildfire, potentially with some prey switching to take advantage of prey that use disturbed habitats. Despite that, owl numbers were low and some owls consumed prey that were not available in salvage-logged areas, suggesting that impacts on owls were more severe from the combination of fire and salvage logging than from fire alone. Full article

We report a landscape-scale natural experiment that followed the abundance and demography of forest-floor small mammals and the activity of small mustelids over a 4-year period of an extreme heat wave and abundant coniferous cone crops. Deer mice (Peromyscus maniculatus) and southern red-backed voles (Myodes gapperi) are major species in the coniferous forest-floor small mammal community near Summerland in southern British Columbia, Canada. Their major mammalian predators include the short-tailed weasel (Mustela richardsonii), long-tailed weasel (Neogale frenata), and American marten (Martes americana). We evaluated three hypotheses (H) that may explain the changes in these mammals from 2021 to 2024: (H₁) that large coniferous cone crops in 2022 would have generated high populations of forest-floor small mammals in 2023 owing to enhanced reproductive output and overwinter survival; (H₂) that increased activity of mustelids would have followed population increases, resulting in the decline of small mammal prey in 2024; and (H₃) that the widespread occurrence of cone crops in 2022 would also have elicited the same mammalian responses in 2023 at a second study area (Golden, BC) 276 km and three mountain ranges from Summerland. During the summer periods of each year, small mammal populations were monitored by intensive live-trapping, and mustelid presence was measured via an index of activity based on live traps, fecal scats, and predation events. The mean abundance and reproductive performance of the P. maniculatus and M. gapperi populations increased in response to the coniferous seedfall, thereby supporting H₁. The activity of small mustelids responded positively to increased numbers of small mammal prey and potentially acted in a regulatory and top–down function in these communities, and hence partially support H₂. Similar responses at Summerland and Golden indicated that this seedfall event and changes in the mammalian community occurred at a landscape-scale, thereby providing partial support for H₃. Potential differential effects of large seed crops on consumers did not affect the mean abundance patterns for P. maniculatus but apparently reduced this metric for M. gapperi. Heat waves, induced by anthropogenic climate change, may alter the frequency of coniferous masting events, and their effects may temporarily change the number and species of mammalian seed consumers and their predators. Full article

Research Highlights: We report a 45-year time-line of forest restoration after harvesting and responses of red-backed voles (Myodes gapperi), an indicator species of closed-canopy forests. Background and Objectives: We have a unique long-term window to test four hypotheses that evaluated the relationship of M. gapperi with old forest structural attributes. Materials and Methods: The study began in old-growth lodgepole pine (Pinus contorta var. latifolia) through clearcutting, regeneration, stand thinning, fertilization, and growth to mature forest (1979 to 2024) in southern BC, Canada. Populations of red-backed voles were monitored in all phases of forest restoration. Results: Clearcutting resulted in the extirpation of M. gapperi followed by small (≤2 voles/ha) populations in young (13–23 years) thinned and fertilized stands. At age 33, the mean annual abundance of M. gapperi (6.5 to 8.7/ha) was highest in the heavily thinned and old-growth stands. At age 43, mean numbers of M. gapperi ranged from 2.7 to 4.2/ha in these same stands. Heavily thinned stands had large trees, multi-layered canopies of conifers, and understory patchiness. Conclusions: This is the first report of long-term responses of M. gapperi to the restoration of mature forest. M. gapperi is a suitable species for monitoring the recovery of some old forest structural features. Full article

Coarse woody debris on the forest floor contributes to maintenance of forest biodiversity and long-term ecosystem productivity. Down wood is often dispersed over harvested sites during logging activities, thereby leaving piles of postharvest debris as “excess” material at landings and roadsides. These wood residues may be burned in most jurisdictions in North America to reduce a perceived fire hazard. The fire hazard debate needs to acknowledge the documented benefits of woody debris retention while striking a balance among biodiversity, bioenergy, and alternative uses for debris, while reducing ignitions by humans. The burning of excess woody debris also creates smoke, causes the release of greenhouse gas (GHG) emissions, and creates human health issues, particularly for vulnerable individuals. The relationship of wildfire smoke to human health problems is well documented. However, there is no scientific evidence showing that postharvest debris piles are ignition points for forest fires, other than those caused by humans. Wood residues from forest harvesting or natural disturbance wood from wildfire and insect outbreaks may be used as renewable biomass “feedstocks” that could help improve energy supplies and reduce GHG emissions. If not marketable, the management of postharvest debris should seek alternative outlets that do not dispose of debris by burning, but still meet fire hazard abatement requirements. The construction of woody debris structures (e.g., piles and windrows) built at the time of forest harvesting and log processing, or later at the site preparation stages, has positive benefits for wildlife habitat and forest biodiversity. A windrow or series of piles may connect patches and reserves of mature forest and riparian areas on clearcut openings. Piles and windrows have consistently provided habitat on new clearcuts for southern red-backed voles (Myodes gapperi) and Microtus voles, as well as a host of other forest-floor small mammal species, at least up to 12 years postconstruction. Woody debris provides important habitat for foraging and cover attributes for marten (Martes americana), weasels (Mustela spp.), and other furbearers. A list of “What to do?” and “When and Where?” with options for construction of woody debris habitats: poorest, good, better, and best are given. In the cases where fire risk from humans is minimized and there are no marketable wood products, eight alternative management scenarios for postharvest woody debris are provided. These include: (1) piles for wildlife habitat; (2) distribution of debris in partial cut forests; (3) machinery to break up and crush debris; (4) protection of riparian zones with barriers for cattle; (5) construction of range fencing; (6) reclamation of landings and skid-trails; (7) soil fertility and reduction in weed competition and drought for planted conifers; and (8) slope stabilization and revegetation. Advantages and disadvantages (if known) are given for each alternative. A flow chart for the fate of excess postharvest woody debris with respect to fire hazard abatement and markets or nonmarkets is given. Full article