Influence of nutrients,disturbances and site conditions on carbon stocks along a boreal forest transect in central Canada

The interacting influence of disturbances and nutrient dynamics on aboveground biomass, forest floor, and mineral soil C stocks was assessed as part of the Boreal Forest Transect Case Study in central Canada. This transect covers a range of forested biomes–-from transitional grasslands (aspen parkland) in the south, through boreal forests, and into the forested subarctic woodland in the north. The dominant forest vegetation species are aspen, jack pine and spruce. Disturbances influence biomass C stocks in boreal forests by determining its age-class structure, altering nutrient dynamics, and changing the total nutrient reserves of the stand. Nitrogen is generally the limiting nutrient in these systems, and N availability determines biomass C stocks by affecting the forest dynamics (growth rates and site carrying capacity) throughout the life cycle of a forest stand. At a given site, total and available soil N are determined both by biotic factors (such as vegetation type and associated detritus pools) and abiotic factors (such as N deposition, soil texture, and drainage). Increasing clay content, lower temperatures and reduced aeration are expected to lead to reduced N mineralization and, ultimately, lower N availability and reduced forest productivity. Forest floor and mineral soil C stocks vary with changing balances between complex sets of organic carbon inputs and outputs. The changes in forest floor and mineral soil C pools at a given site, however, are strongly related to the historical changes in biomass at that site. Changes in N availability alter the processes regulating both inputs and outputs of carbon to soil stocks. N availability in turn is shaped by past disturbance history, litter fall rate, site characteristics and climatic factors. Thus, understanding the life-cycle dynamics of C and N as determined by age-class structure (disturbances) is essential for quantifying past changes in forest level C stocks and for projecting their future change.     

Electrophysiological measurements of spectral mechanisms in the retinas of two cervids: white-tailed deer (Odocoileus virginianus) and fallow deer (Dama dama)

Electroretinogram (ERG) flicker photometry was used to study the spectral mechanisms in the retinas of white-tailed deer (Odocoileus virginianus) and fallow deer (Dama dama). In addition to having a rod pigment with maximum sensitivity (_max) of about 497 nm, both species appear to have two classes of photopic receptors. They share in common a short-wavelength-sensitive cone mechanism having _max in the region of 450–460 nm. Each also has a cone having peak sensitivity in the middle wavelengths, but these differ slightly for the two species. In white-tailed deer the _max of this cone is about 537 nm; for the fallow deer the average _max value for this mechanism was 542 nm. Deer resemble other ungulates and many other types of mammal in having two classes of cone pigment and, thus, the requisite retinal basis for dichromatic color vision.Abbreviations ERG electroretinogram - LWS long wavelength sensitive - MWS middle wavelength sensitive - SWS short wavelength sensitive     

Seed dispersal by white-tailed deer: implications for long-distance dispersal,invasion, and migration of plants in eastern North America

For many plant species in eastern North America, short observed seed dispersal distances (ranging up to a few tens of meters) fail to explain rapid rates of invasion and migration. This discrepancy points to a substantial gap in our knowledge of the mechanisms by which seeds are dispersed long distances. We investigated the potential for white-tailed deer (Odocoileus virginianus Zimm.), the dominant large herbivore in much of eastern North America, to disperse seeds via endozoochory. This is the first comprehensive study of seed dispersal by white-tailed deer, despite a vast body of research on other aspects of their ecology. More than 70 plant species germinated from deer feces collected over a 1-year period in central New York State, USA. Viable seeds included native and alien herbs, shrubs, and trees, including several invasive introduced species, from the full range of habitat types in the local flora. A mean of >30 seeds germinated per fecal pellet group, and seeds were dispersed during all months of the year. A wide variety of presumed dispersal modes were represented (endo- and exozoochory, wind, ballistic, ant, and unassisted). The majority were species with small-seeded fruits having no obvious adaptations for dispersal, underscoring the difficulty of inferring dispersal ability from diaspore morphology. Due to their broad diet, wide-ranging movements, and relatively long gut retention times, white-tailed deer have tremendous potential for effecting long-distance seed dispersal via ingestion and defecation. We conclude that white-tailed deer represent a significant and previously unappreciated vector of seed dispersal across the North American landscape, probably contributing an important long-distance component to the seed shadows of hundreds of plant species, and providing a mechanism to help explain rapid rates of plant migration.Electronic Supplementary Material Supplementary material is available in the online version of this article at     

Effects of white-tailed deer on the population dynamics of acorns,seedlings and small saplings of Quercus buckleyi

To measure the effects of white-tailed deer (Odocoileus virginianus) herbivory on seeds, seedlings, and young saplings of Quercus buckleyi on the eastern Edwards Plateau of central Texas, USA, experimental fenced deer exclosures were constructed. Acorns or small Q. buckleyi transplants were placed in each exclosure and in each unfenced control plot. Deer did not significantly affect acorn survival and germination, but did significantly reduce transplant survival and growth rates. The results support the hypothesis that deer are responsible for the failure of recruitment into adult size classes in Q. buckleyi populations in this region. Without adult recruitment of Q. buckleyi, the species composition and possibly even the physiognomy of woodlands on the eastern Edwards Plateau will change markedly. The results of this experiment also indicate that, although juniper (Juniperus ashei) and Q. buckleyi presumably compete for water, light, and nutrients, in the presence of deer junipers can have a positive effect on seedlings and saplings of Q. buckleyi, a case of facilitation. In the presence of deer the transplants increased in height significantly more slowly away from juniper saplings than they did beneath juniper saplings, probably due to the physical protection from browsing that junipers provided to the transplants.     

Variations of bioavailable Sr concentration and 87Sr/86Sr ratio in boreal forest ecosystems

The mean depth of Sr and water uptake in mixed Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) stands was investigated, using natural variations of ⁸⁷Sr/⁸⁶Sr and ¹⁸O/¹⁶O in soils in relation to depth. Three spruce-pine pairs were studied on a podzol and a peat site in Northern Sweden. Tree leaf and wood, as well as soils, soil solutions and roots below each tree were analysed for Sr and Ca concentrations and ⁸⁷Sr/⁸⁶Sr ratio. The ¹⁸O/¹⁶O ratio was also determined in xylem sap and soil solutions in relation to depth. Soil solution ¹⁸O/¹⁶O decreased in relation to depth. Comparing with xylem sap ¹⁸O/¹⁶O data indicated a deeper uptake of soil water by pine than spruce on the podzol site and a superficial uptake by both species on the peat. The ⁸⁷Sr/⁸⁶Sr ratio of bioavailable Sr generally increased in soils in relation to depth. Contrastingly, the ⁸⁷Sr/⁸⁶Sr ratio in spruce wood was generally higher than in pine wood suggesting a deeper uptake of Sr by spruce. But the ⁸⁷Sr/⁸⁶Sr ratio and concentrations of bioavailable Sr were systematically higher below spruce than below pine. In order to explain these unexpected results, we built a simple flux model to investigate the possible effects of interspecific variations in Sr cycling, soil mineral weathering and depth of Sr uptake on soil and tree ⁸⁷Sr/⁸⁶Sr ratio. At the study sites, spruce cycled in litterfall up to 12 times more strontium than pine. The use of the model showed that this difference in Sr cycling could alone explain higher isotopic signatures of trees and topsoils below spruce. Besides, high isotopic signatures of roots in the A/E horizons below spruce led us to hypothesise a species-specific weathering process. Finally, the comparison between the ⁸⁷Sr/⁸⁶Sr ratios in wood and root or soil solutions below each species suggested that the average depth of Sr and water uptake were close, but irregular variations of the Sr isotopic ratio with depth reduce the accuracy of the results. Tree species strongly influence Sr isotopic ratios in boreal forest soils through differences in Sr cycling, and possibly through specific mineral weathering.     

Neighborhood interactions influencing tree population dynamics in nonpyrogenous boreal forest in northern Finland

Open-canopy moss-rich woodlands dominated by Picea abies and Betula pubescens in northern Finland may undergo cyclic development with reciprocal replacement of the tree species due to the positive feedbacks on soil conditions. Although relations to the abiotic environment are well understood, intra- and interspecific interactions during development of sparse boreal forests have received less attention. We studied tree regeneration, growth and survival with respect to size and density of neighboring trees in four stands representing roughly four stages of the Picea–Betula forest cycle. We conducted spatial analysis (Ripley’s K-function) of mapped locations of live and dead stems to reconstruct the distribution of stems prior to mortality, and to infer possible causes of tree population decline. The prevalence of standing dead stems enabled us to test if mortality was associated with density and size of neighboring trees. Logistic regression was used to test for relationships between tree survival and local crowding indices. We also examined spatial autocorrelations of individual size characteristics to determine the mode and spatial extent of tree interactions. Picea abies had reduced recruitment in open areas occupied by mosses and dwarf-shrubs, and preferentially regenerated near B. pubescens, whereas B. pubescens formed small clumps (and occasionally these consisted entirely of stems from a single tree) that showed local repulsion from large P. abies trees. Size of neighboring trees was the primary determinant of individual growth and survival, whereas neighborhood density per se had only a weak effect. Picea abies had negatively correlated sizes among close neighbors (0–4 m radius) indicating that dominant trees suppress their smaller neighbors. Negative autocorrelations prevailed at the transition stages where the patches of smaller trees were concentrated around evenly spaced large trees. Tree sizes became spatially independent at the mature phase. We hypothesize that both low light and soil nutrient availability causes the P. abies population decline. Dominant trees in this high latitude forest have large light depletion zones and shallow root system to promote strong above- and below-ground competition with younger trees. Higher mortality rates within canopy patches were not compensated for by recruitment in gaps, causing P. abies population to decline steadily.     

An experimental study of factors affecting the distribution of yellow perch and central mudminnows along a species richness gradient

Synopsis Effects of environmental factors on the distribution and abundance of yellow perch and central mudminnows in northern Wisconsin were examined by holding populations of these fishes within single-species enclosures in a series of three small forest lakes having a species-richness gradient of one to four species. These enclosures allowed each species to experience environmental conditions within each lake without directly interacting with each other. In the four-species lake, two other sets of enclosures addressed the effects of intra- and interspecific competition. Changes in total biomass of enclosure stocks (from growth and mortality) indicated that in the absence of other species, perch did best in the lake containing the richest fish assemblage, intermediate in the two-species lake, and worst in the mudminnow-only lake. Mudminnow stocks similarly performed significantly better in the four-species lake than the mudminnow-only lake. These results suggest that the lakes' environmental conditions contribute to the patterns of presence and abundance of perch, but that interspecific interactions override a similar contribution for the mudminnow, which is regarded as a fugitive species. Perch performances were also sensitive to fish densities within enclosures, declining significantly when stocks were doubled, either by adding more perch or equal numbers of mudminnows.     

Changes in diversity along a successional gradient in a Costa Rican upper montane Quercus forest

Changes in terrestrial vascular plant diversity along a successional gradient were studied in a Costa Rican upper montane Quercus forest. In 1991 and 1992 species presence and cover were recorded in 12 successional 0.1 ha forest plots. A total of 176 species in 122 genera and 75 families were found. Asteraceae was the most speciose family. With the help of TWINSPAN three successional phases were classified: (i) Early Secondary Forest (ESF, 145 spp.), (ii) Late Secondary Forest (LSF, 130 spp.) and (iii) Primary Forest (PF, 96 spp.). Detrended Correspondence Analysis (DCA) species ordination using DECORANA illustrates that different ecological species groups can be distinguished along the time sequence. Alpha diversity (Shannon-Wiener index, among others) in ESF and LSF was significantly greater than in PF. This is probably explained by downslope migration of numerous sub(alpine) species to cleared and recently abandoned montane sites. Beta diversity applying Sørensen's similarity coefficients declined during succession. Using linear regression, the minimum time required for floristic recovery following disturbance and abandonment was calculated at 65.9 years. A comparison with other studies shows that secondary forests in upper montane Costa Rica can be as diverse as in neotropical lowlands.     

Succession in the southern part of the Canadian boreal forest

Forest succession following fire in a forest mosaic of northwestern Quebec has been studied in order to: (1) describe the successional pathways using communities of different ages and (2) evaluate convergence of successional pathways and possible effect of fire suppression on the establishment of steady-state communities. As a first step, ordination and classification techniques were used in order to remove changes in forest composition which are related to abiotic conditions. Then, ordinations based on tree diameter distributions were used to study shifts in species composition in relation to time since the last fire.Even under similar abiotic conditions, successional pathways are numerous. However, regardless of forest composition after fire, most stands show convergence toward dominance of Thuja occidentalis and Picea mariana on xeric sites and dominance of Abies balsamea and Thuja occidentalis on more mesic sites. Stable communities of >300 yr occur on xeric sites while on mesic sites directional succession still occurs after 224 yr. Nearly all species involved in succession are present in the first 50 yr following fire. Only Abies balsamea and Thuja occidentalis increase significantly in frequency during succession. Following initial establishment, successional processes can generally be explained by species longevity and shade tolerance. Early successional species may be abundant in the canopy for more than 200 yr while the rapid decrease of Picea glauca, a late successional species could be related to spruce budworm outbreaks. Considering the short fire rotation observed (about 150 yr), a steady-state forest is unlikely to occur under natural conditions, though it may be possible if fire is controlled.     

Aboveground and belowground responses to quality and heterogeneity of organic inputs to the boreal forest

Leaf litter and other organic resources returned to the soil are important regulators of ecological processes in forest ecosystems, and their ecological impacts may be strongly influenced both by their quality and by interactions between coexisting resource types. To date, most studies on effects of resource identity and mixing have only involved leaf litter, despite the fact that other resource types constitute a major input to the soil. We investigated how quality and heterogeneity of organic substrates found in boreal forests affects the activity and community structure of soil microbes, and plant growth. Six organic substrates (wood, charcoal, berries, sporocarps, vertebrate faeces and leaf litter) were added singly or in mixtures of two, three and six resource types to pots containing forest soil (with or without tree seedlings of Betula pendula Roth). The largest positive effects of single substrates on microbial basal respiration (BR), substrate-induced respiration (SIR) and microbial metabolic quotient (qCO₂) were found for nutrient-rich substrates (faeces and sporocarps) or substrates with high sugar-content (berries). Mixing of substrates had no effect on BR or SIR, but decreased qCO₂ or altered the microbial community structure for specific combinations of substrates. In contrast to the niche complementarity hypothesis, microbial catabolic diversity was not stimulated by greater diversity of resources. Seedling growth responses to single substrates were neutral or negative; the inhibition of growth probably resulted largely from microbial competition for nutrients. Substrate mixing enhanced seedling nutrient-uptake and growth for all mixtures containing sporocarps and leaf litter. Overall, plants responded more strongly to resource heterogeneity than microbes, and synergistic effects only occurred when nutrient-rich substrates were present within the substrate mixtures. In particular, our results demonstrate a role for complex and non-additive interactions among previously overlooked resource types returned to the soil in influencing ecosystem functions such as nutrient cycling and plant productivity.     

Distribution and size of capercaillie leks in relation to old forest fragmentation

Summary Distribution and size of 38 capercaillie Tetrao urogallus leks were related to amount and configuration of old forest patches in two south-east Norwegian coniferous forests. The smallest occupied patch was 48 ha containing a solitary displaying cock. All patches larger than 1 km² contained leks. Number of cocks per lek increased with increasing patch size. Number of leks per patch increased in a step-wise manner with one lek added for each 2.5–3 km² increase in patch size. In large patches there was one lek per 3–5 km² old forest, and density of lekking cocks was 2–2.5 per km². In small patches density of cocks varied considerably. Density of cocks was not related to patch isolation or patch shape. However, among leks surrounded by 50–60% old forest within a 1 km radius, number of cocks increased with increasing old forest fine-graininess. We argue that when old forests cover more than 50%, a fine-grained mosaic may support higher densities of lekking cocks than a coarse-grained mosaic. Conversely, when old forests cover less than 50%, a fine-grained mosaic is unfavourable, because each old forest patch becomes too small and isolated. Finally, we present a predictive model of how old forest fragmentation influences density of leks, number of cocks per lek, and total density of cocks.     

Competition between Salicornia europaea and Atriplex prostrata (Chenopodiaceae) along an experimental salinity gradient

Salicornia europaea L. is a halophyte that often occupies the lowestand most saline (>3.5% total salt) areas of salt marshes. Atriplexprostrata Boucher is less salt tolerant than S. europaea and oftengrows in a less saline (<2.0% total salts) zone adjacent to S. europaea. The purpose of this experiment was to determine thecompetitive outcome when these two species are grown at differentsalinities to ascertain the extent salinity and competition affect plantzonation. Plants were grown in a de Wit replacement series at 85, 170,and 340 mM NaCl in half-strength Hoagland's no. 2 nutrient solution fortwo months. There was a significant effect of salt concentration,competition, and their interaction on biomass production of S. europaea plants. However, only salt concentration significantly affectedbiomass production of A. prostrata plants. Results of thisexperiment confirmed the results of other studies that demonstrated thatthe more salt tolerant species were less competitive at lower salinities. Atriplex prostrata was the better competitor at 85 mM NaCl, whereasS. europaea was the better competitor at 340 mM NaClbecause growth of A. prostrata was inhibited. At 170 mMNaCl, A. prostrata biomass production decreased more than S. europaea biomass in mixed culture.     

Concentrations of insulin-like growth factor-I in adult male white-tailed deer (Odocoileus virginianus): associations with serum testosterone, morphometrics and age during and after the breeding season

Our understanding of insulin-like growth factor-I (IGF-I) in cervids has been limited mostly to its effects on antler development in red deer (Cervus elaphus), roe deer (Capreolus capreolus), fallow deer (Dama dama), and pudu (Pudu puda). Although IGF-I has been found to play a critical role in reproductive function of other mammals, its role in reproduction of deer is unknown. The objectives of the present study were to determine if serum levels of IGF-I change during the breeding season, assess whether age influences serum IGF-I, compare levels of IGF-I measured during and following the breeding season, and determine if IGF-I is associated with body and antler characteristics in free-ranging adult, male white-tailed deer (Odocoileus virginianus). We collected serum and morphometric data from hunter-harvested and captured white-tailed deer to investigate these objectives. Mean level of serum IGF-I during the breeding season was 63.6 ng/ml and was greatest in deer between 2.5 and 5.5 years old (57.4-79.9 ng/ml). Levels of serum IGF-I decreased by approximately 40% as the breeding season progressed, but levels were less in deer following the breeding season (34.6 ng/ml). Both body and antler size were associated positively with IGF-I when controlling for age. Serum testosterone was also associated positively with IGF-I. Levels of serum testosterone during the breeding season generally increased with age from 4.82 (1.5 years old) to 18.79 ng/dl (5.5 years old), but decreased thereafter. These data suggest that IGF-I may be an important hormone in breeding, male white-tailed deer.     

White-tailed deer (Odocoileus virginianus) fecal pellet decomposition is accelerated by the invasive earthworm Lumbricus terrestris

Exotic European earthworms have expanded into worm-free forests of the United States. Concurrently, populations of the white-tailed deer, Odocoileus virginianus, have also increased. During winter, deer use hemlock stands for cover while browsing elsewhere, creating a net organic matter flux into these stands. Deer fecal pellets can provide annual inputs of 48.1 kg C, 1.4 kg N, and 1.3 kg Ca per hectare. We tested the hypothesis that these pellets were readily consumed by invading earthworms. The litter-feeding anecic earthworm Lumbricus terrestris redistributed fecal pellets and accelerated mass and nutrient loss rates. These losses are likely due to the combination of enhanced fragmentation and decomposition as earthworms drag pellets into their burrows for consumption. This nutrient subsidy may be an important source of high quality “litter” input to hemlock stands, which may in turn facilitate the invasion of these stands by earthworms under high deer densities.     

Diversity of dung-beetle community in declining Japanese subalpine forest caused by an increasing sika deer population

The Ohdaigahara subalpine plateau in Japan has recently suffered a reduction in primary forest land caused by an increasing population of sika deer (Cervus nippon). Deer have debarked many trees, causing dieback, gradually changing the primary forest first to light forest with a floor that is densely covered with sasa grass (Sasa nipponica) and then to S. nipponica grassland. To examine the effects of vegetative transformation on the dung-beetle community, we compared the diversity and abundance of dung-beetle assemblages in the primary forest, transition forest, and S. nipponica grassland using dung-baited pitfall traps. The species richness and species diversity (Shannon-Wiener index) were significantly highest in the primary forest and lowest in the S. nipponica grassland. The evenness (Smith-Wilson index) was highest in the primary forest and nearly equal in the transition forest and S. nipponica grassland. The abundance was apparently greater in the transition forest than in the primary forest and S. nipponica grassland. These results suggest that loss of primary forest resulting from an increasing deer population decreases the diversity of the dung-beetle community while increasing the abundance of dung beetles in the transition forest. Sika deer use transition forests and grasslands more frequently than primary forests as habitat, but an increase in dung supply there does not necessarily increase the diversity or abundance of dung-beetle assemblages.     

Successional and physical controls on the retention of nitrogen in an undisturbed boreal forest ecosystem

Floristic succession in the boreal forest can have a dramatic influence on ecosystem nutrient cycling. We predicted that a decrease in plant and microbial demand for nitrogen (N) during the transition from mid- to late-succession forests would induce an increase in the leaching of dissolved inorganic nitrogen (DIN), relative to dissolved organic nitrogen (DON). To test this, we examined the chemistry of the soil solution collected from within and below the main rooting zones of mid- and late-succession forests, located along the Tanana River in interior Alaska. We also used a combination of hydrological and chemical analyses to investigate a key assumption of our methodology: that patterns of soil water movement did not change during this transition. Between stands, there was no difference in the proportion of DIN below the rooting zone. 84–98% of DIN at both depths consisted of nitrate, which was significantly higher in the deeper mineral soil than at the soil surface (0.46±0.12 mg NO⁻ ₃ –N l⁻¹ vs 0.17±0.12 mg NO⁻ ₃ –N l⁻¹, respectively), and 79–92% of the total dissolved N consisted of DON. Contrary to our original assumption that nutrients were primarily leached downward, out of the rooting zone, we found much evidence to suggest that the glacially-fed Tanana River (>200 m from these stands) was contributing to the influx of water and nutrients into the soil active layer of both stands. Soil water potentials were positively correlated with river discharge; and ionic and isotopic (δ¹⁸O of H₂O) values of the soil solution closely matched those of river water. Thus, our ability to elucidate biological control over ecosystem N retention was confounded by riverine nutrient inputs. Climatic warming is likely to extend the season of glacial melt and increase riverine nutrient inputs to forests along glacially-fed rivers.     

Nitrogen dynamics of a boreal black spruce wildfire chronosequence

This study examined the nitrogen (N) dynamics of a black spruce (Picea mariana (Mill.) BSP)-dominated chronosequence in Manitoba, Canada. The seven sites studied each contained separate well- and poorly drained stands, originated from stand-killing wildfires, and were between 3 and 151 years old. Our goals were to (i) measure total N concentration ([N]) of all biomass components and major soil horizons; (ii) compare N content and select vegetation N cycle processes among the stands; and (iii) examine relationships between ecosystem C and N cycling for these stands. Vegetation [N] varied significantly by tissue type, species, soil drainage, and stand age; woody debris [N] increased with decay state and decreased with debris size. Soil [N] declined with horizon depth but did not vary with stand age. Total (live + dead) biomass N content ranged from 18.4 to 99.7 g N m⁻² in the well-drained stands and 37.8–154.6 g N m⁻² in the poorly drained stands. Mean soil N content (380.6 g N m⁻²) was unaffected by stand age. Annual vegetation N requirement (5.9 and 8.4 g N m⁻² yr⁻¹ in the middle-aged well- and poorly drained stands, respectively) was dominated by trees and fine roots in the well-drained stands, and bryophytes in the poorly drained stands. Fraction N retranslocated was significantly higher in deciduous than evergreen tree species, and in older than younger stands. Nitrogen use efficiency (NUE) was significantly lower in bryophytes than in trees, and in deciduous than in evergreen trees. Tree NUE increased with stand age, but overall stand NUE was roughly constant (∼ ∼150 g g⁻¹ N) across the entire chronosequence.     

Influence of a deer carcass on Coleopteran diversity in a Scandinavian boreal forest: a preliminary study

We tested the effect of a large ungulate carcass on boreal forest biodiversity by contrasting the local abundance and diversity of Coleoptera around a roe deer Capreolus capreolus carcass and in a control plot, between 8 August and 3 September 2003, in southern Norway. The two plots differed both in occurrence and richness of species, which were almost double at the carcass plot, although the diversity indices were similar. The higher evenness of the control plot compensated for its lower number of species, probably because the carcass plot was a disturbed area, colonized by many species, which were represented by few individuals. The number of beetles captured each day correlated positively with temperature at the control plot, but not at the carcass plot, indicating that the presence of an abundant and concentrated resource increased the local activity of Coleoptera. The carcass is likely to create a particular microclimate, which could partly buffer against extremes of air-temperature variation. These preliminary results indicate that ungulate carcasses have a significant ecological impact, which should be further investigated to improve the management and restoration of European boreal forest ecosystems.