雪被去除对川西亚高山云杉林土壤活性氮的影响

气候变化引发的季节性雪被改变可能对高寒森林土壤氮循环产生深刻影响.以遮雪棚去除雪被,研究了雪被去除样方和对照样方在不同关键时期(雪被初期、深雪被期和雪被融化期)土壤氮库和矿化速率的变化.结果表明: 季节性雪被对土壤具有良好的保温作用,雪被去除使得5 cm深度土壤平均温度和最低温度分别降低0.33和1.17 ℃,并明显增加了土壤冻结深度和冻融循环.土壤活性氮在不同雪被时期存在显著差异.雪被去除使得冬季土壤铵态氮、硝态氮和可溶性有机氮增加38.6%、23.5%和57.3%.此外,雪被去除也促进了融化期土壤硝化和矿化速率的增加.因此,未来气候变暖引起的雪被减少可能加快川西亚高山森林冬季土壤氮循环.     

The dilemma of where to nest: influence of spring snow cover,food proximity and predator abundance on reproductive success of an arctic-breeding migratory herbivore is dependent on nesting habitat choice

Pink-footed geese Anser brachyrhynchus nest in two contrasting but commonly found habitats: steep cliffs and open tundra slopes. In Svalbard, we compared nest densities and nesting success in these two environments over ten breeding seasons to assess the impact of spring snow cover, food availability to nesting adults and arctic fox Vulpes lagopus (main terrestrial predator) abundance. In years with extensive spring snow cover, fewer geese at both colonies attempted to breed, possibly because snow cover limited pre-nesting feeding opportunities, leaving adults in poor breeding condition. Nesting success at the steep cliff colony was lower with extensive spring snow cover; such conditions force birds to commit to repeated and prolonged recess periods at far distant feeding areas, leaving nests open to predation. By contrast, nesting success at the open tundra slope was not affected by spring snow cover; even if birds were apparently in poor condition they could feed immediately adjacent to their nests and defend them from predators. Foxes were the main nest predator in the open tundra slopes but avian predators likely had a larger impact at the steep cliffs colony. Thus, the relative inaccessibility of the cliffs habitat may bring protection from foxes but also deprives geese from readily accessing feeding areas, with the best prospects for successful nesting in low spring snow cover years. Our findings indicate that spring snow cover, predator abundance and food proximity did not uniformly influence nesting success of this herbivore, and their effects were dependent on nesting habitat choice.     

Snow cover manipulations alter survival of early life stages of cold‐temperate tree species

Projections of future climate suggest increases in global temperatures that are especially pronounced in winter in cold‐temperate regions. Thermal insulation provided by snow cover to litter, soil, and overwintering plants will likely be affected by changing winter temperatures and might influence future species composition and ranges. We investigated effects of changing snow cover on seed germination and sapling survival of several cold‐temperate tree species using a snow manipulation approach. Post‐winter seed germination increased or decreased with increasing snow cover, depending on species; decreased seed germination was found in species that characteristically disperse seed in summer or fall months prior to snowfall. Post‐winter sapling survival increased with increasing snow cover for all species, though some species benefitted more from increased snow cover than others. Sapling mortality was associated with root exposure, suggesting the possibility that soil frost heaving could be an important mechanism for observed effects. Our results suggest that altered snow regimes may cause re‐assembly of current species habitat relationships and may drive changes in species’ biogeographic range. However, local snow regimes also vary with associated vegetation cover and topography, suggesting that species distribution patterns may be strongly influenced by spatial heterogeneity in snow regimes and complicating future projections.     

The effect of cover plants management on soil invertebrate fauna in vineyard in Northern Italy

Cover crops are largely used in vineyard management to improve ecological services such as pest and weed control, soil protection from erosion and soil water balance. Few data are available about the effects of cover crops on soil fauna and, in particular, on important generalist predators such as Carabidae and Araneae. We compare the effects of five different cover crops treatments: Sweet Alyssum, Phacelia, Buckwheat, Faba bean and a mixture of Vetch and Oat. A three years experimental trial was developed in Northern Italy. Soil fauna was investigated using pitfall traps. Cover crops seriously affected soil fauna of most taxa. Higher abundance of predators, in particular Carabidae and Staphylinidae, was present in treatments with legumes (Faba bean and Vetch and Oat) while soil Araneae seemed not to be affected. No vineyard pests seemed to be positively affected by cover crops. We confirm the importance of cover crops in increasing soil predator abundance and consequently improving pest control.     

Relation of the snow cover to the structure of vegatation in the alpine communities of the eastern Tsinghai-Tibet Plateau

The type of snow cover considerably influences the sctructure of vegetation and production-related processes in alpine communities of diverse regions. The relation of snow cover thickness to the structure of apline plant communities in the eastern Tsinghai-Tibet Plateau (Sichuan, People's Republic of China) was studied by analyzing the vegetation in 251 sample areas grouped in five transects along the gradient of mesotopographic conditions and wintertime snow cover thickness. Considerable differentiation of plant communities related to snow cover thickness in revealed along the line from the northern to the southern slope. It is shown that the influence of snow cover on the distribution of particular plant species is significantly greater than the influence of soil properties (pH, content of humus, total phosphorus, potassium, and ammonia nitrogen in the upper strata of soil). Among the 56 herbaceous plant species and 7 shrub species studied, 52 herbaceous and all the 7 shrub species showed significant (P < 0.05) correlation (positive or negative) to snow cover thickness. Snow cover thickness appeared also significantly correlated to a number of soil properties: soil thickness, content of water, total phosphorus, and humus. But, in contrast to the alpine communities of the Caucasus and the Alps, no considerable acidification of the soil under snowflakes, due to perpetual removal of cations by melt water, was observed.     

The diversity of beetle assemblages in different habitat types in Sabah, Malaysia

The diversity of beetle assemblages in different habitat types (primary forest, logged forest, acacia plantation and oil palm plantation) in Sabah, Malaysia was investigated using three different methods based on habitat levels (Winkler sampling, flight-interception-trapping and mist-blowing). The overall diversity was extremely high, with 1711 species recorded from only 8028 individuals and 81 families (115 family and subfamily groups). Different degrees of environmental changes had varying effects on the beetle species richness and abundance, with oil palm plantation assemblage being most severely affected, followed by acacia plantation and then logged forest. A few species became numerically dominant in the oil palm plantation. In terms of beetle species composition, the acacia fauna showed much similarity with the logged forest fauna, and the oil palm fauna was very different from the rest. The effects of environmental variables (number of plant species, sapling and tree densities, amount of leaf litter, ground cover, canopy cover, soil pH and compaction) on the beetle assemblage were also investigated. Leaf litter correlated with species richness, abundance and composition of subterranean beetles. Plant species richness, tree and sapling densities correlated with species richness, abundance and composition of understorey beetles while ground cover correlated only with the species richness and abundance of these beetles. Canopy cover correlated only with arboreal beetles. In trophic structure, predators represented more than 40% of the species and individuals. Environmental changes affected the trophic structure with proportionally more herbivores (abundance) but fewer predators (species richness and abundance) in the oil palm plantation. Biodiversity, conservation and practical aspects of pest management were also highlighted in this study.     

Effects of snow accumulation on survival of beech (Fagus crenata) seed

The escape of beech seeds from seed predators and winter desiccation due to snow accumulation was studied by comparing two sites in Japan: one site that experiences much snow and another site that experiences less snow cover. At the site with greater snow cover, about 70% of the beech seeds escaped seed predation by rodents during winter and about 70% of surviving seeds germinated successfully in spring. At the site with less snow cover, however, all of the beech seeds were eaten by rodents, and all seeds that were protected from feeding were killed by winter desiccation. We confirmed that snow prevents beech seeds from predation by rodents because it conceals their sight and scent. These effects are one of the main reasons why beeches in snowy areas regenerate constantly and those in less snowy areas do not.     

Gradients in density variations of small rodents: the importance of latitude and snow cover

Summary Microtine rodents are known to show extreme population variations (cycles) but non-cyclic populations have also been recognized during recent years. The cyclic populations have been widely thought to be regulated by intrinsic mechanisms. However, such predictions for cyclic populations are usually not applicable to non-cyclic ones and extrinsic factors may have to be included in any explanation.A hypothesis that the degree of fluctuations in small rodent numbers is related to the sustainable number of generalist predators was tested on mainly literature data by computing indices of cyclicity for local populations. These indices were related to latitude and snow cover (two measures) as these variables will affect the amount of alternative prey available for these generalists. Within Fennoscandia such indices for Clethrionomys glareolus and Microtus agrestis were clearly positively related to latitude and snow cover. The fraction of populations with summer declines in numbers, characterizing highly cyclic populations, increased in the same way. Cyclicity indices in Great Britain were similar to those in southern Fennoscandia, both areas being poor in snow, but were higher at the same latitudes in eastern Europe with more snow. Indices of density variations were generally low in North American Clethrionomys species and very variable in Microtus species.The gradients observed and differences between continents are interpreted as due to microtine-vegetation interactions in northern European areas poor in generalist predators but with important small mustelid predation, and to similar snowshoe hare-vegetation interactions in mainly Canada-Alaska, where small rodents may serve as alternative prey for numerically fluctuating hare predators, at least in the forests. Western European microtine populations, and probably many others, seem to be regulated by generalist predators.     

兴安鹿蹄草叶片雪盖初期与雪盖后期保护酶活性的变化规律

研究了自然生境下生长的兴安鹿蹄草(Pyrola dahurica)叶片在雪盖初期、后期的细胞膜相对透性、膜质过氧化产物丙二醛(MDA)含量、超氧化物歧化酶(SOD)及过氧化物酶(POD)活性的变化, 结果表明: 兴安鹿蹄草顺利越冬取决于两个关键时期, 即雪盖初期和雪盖后期, 雪盖初期包括积雪期和盛雪期, 雪盖后期包括融雪初期和融雪后期。积雪期(11月1日~12月1日)兴安鹿蹄草随着温度的降低叶片中的MDA含量逐渐增高, 细胞膜相对透性增大, SOD和POD活性增强; 进入盛雪期(12月1日以后), 雪盖下温度较高而恒定, 兴安鹿蹄草叶片MDA含量减少, 细胞膜相对透性减低, SOD和POD活性减弱。翌年春天融雪初期(3月1日~3月15日), 雪盖下温度降低, 兴安鹿蹄草叶片中的MDA含量增高, 但低于积雪期; 细胞膜相对透性增大, 且高于积雪期; SOD和POD活性增强, 但低于积雪期; 融雪后期(3月中旬以后)兴安鹿蹄草叶片MDA含量减少, 细胞膜相对透性减低, SOD和POD活性减弱。     

Soil fauna responses to invasive alien plants are determined by trophic groups and habitat structure: a global meta‐analysis

Despite increasing frequency of invasions by alien plant species with widespread ecological and economic consequences, it remains unclear how belowground compartments of ecosystems are impacted. In order to synthetize current knowledge and provide future directions for research we performed a meta‐analysis assessing the impact of invasive alien plant species on soil fauna abundance. Compared to previous synthesis on this topic, we included together in our model the trophic group of each soil faunal taxa (from herbivores to predators) and habitat structure, namely open and closed habitats (i.e. grass and shrub dominated areas versus forested areas). In doing so, we highlighted that both moderators strongly interact to determine the response of soil fauna to the presence of invasive alien plants. Soil fauna abundance increase in the presence of invasive species only in closed habitats (+18.2%). This pattern of habitat‐dependent response (positive effect in closed habitats) was only found for primary consumers (i.e. herbivores +29.1% and detritivores +66.7%) within both detritus‐based and live root‐based trophic pathways. Abundances of predators and microbivores did not respond to the presence of IAS irrespective of habitat structure. For several groups, the habitat structure (open or closed) significantly drove their responses to the presence of invasive alien species. In addition, we carefully considered potential sources of bias (e.g. geographic, taxonomic and functional) within the collected data in an attempt to highlight gaps in available knowledge on the subject. Our findings support the conclusions of previous studies on the subject by demonstrating 1) that soil fauna abundance is impacted by biological invasions, 2) that initial habitat structure has a strong influence on the outcome and 3) that responses within the soil fauna differ between trophic levels with a stronger response of primary consumers.     

Effects of snow cover on the benthic fauna in a glacier-fed stream

1. Alpine streams above the tree line are covered by snow for 6–9 months a year. However, winter dynamics in these streams are poorly known. The annual patterns of macroinvertebrate assemblages were studied in a glacial stream in the Austrian Alps, providing information on conditions under the snow.
2. Snow cover influenced water temperature, the content of benthic organic matter and insect development. Taxa richness and abundance of macroinvertebrates did not show a pronounced seasonal pattern. The duration of the autumn period with stable stream beds was important in determining the abundance and composition of the winter fauna.
3. There were significant differences in species composition between summer and winter. Two potential strategies in larval survival were evident: adaptation to the extreme abiotic conditions in summer (e.g. Diamesa spp.) or avoidance of these conditions and development during winter (e.g. Ephemeroptera and Plecoptera).
4. A comparison of a stream reach with continuous snow cover and a stream reach that remained open throughout winter showed that conditions under snow are suboptimal. At the open stream site, with higher water temperatures and greater food supply (benthic organic matter content), abundance and taxa richness was higher and larval growth was faster. Several taxa were found exclusively at this site.
5. Winter conditions did not provide an entirely homogeneous environment, abiotic conditions changed rapidly, especially at the onset of snowfall and at snowmelt. Continuous monitoring is necessary to recognize spatial and temporal heterogeneity in winter environments and the fauna of alpine streams.     

川西高山林线三种灌木凋落叶分解中的无脊椎动物多样性

以无脊椎动物为主体的土壤动物是影响凋落物分解的重要生物因素,对维持陆地生态系统物质循环和能量流动具有重要作用。高山林线交错带是高山植被垂直带谱中重要的过渡区域,拥有比相邻生态系统更高的生境复杂性和物种多样性。林线上温度波动和冻融循环频率显著高于针叶林,为了了解林线交错带上环境差异对凋落物分解过程中的土壤动物群落结构和多样性的影响,采用凋落物分解袋的方法,于高山生态系统的两个主要时期,即雪被末期和生长季末期,研究了林线主要代表性灌木——高山柳(Salix cupularis)、高山杜鹃(Rhododendron lapponicum)和红毛花楸(Sorbus rufopilosa)凋落叶分解的土壤动物多样性特征。结果表明:凋落物中的无脊椎动物群落多样性及个体、类群密度随物种、海拔梯度和季节而变化,且季节差异对无脊椎动物多样性的影响比物种和海拔梯度更显著。3个因子的交互作用不仅影响土壤动物群落多样性和均匀度,而且影响群落个体密度和类群密度。雪被末期,凋落物中的无脊椎动物多样性指数H、均匀度指数J及丰富度指数D以针叶林最高,优势度指数C以林线最高;生长季节末期的无脊椎动物类群密度和个体密度显著高于雪被末期。总体上,凋落物中的无脊椎动物群落丰富度以生长季末期最高,林线较针叶林丰富。这意味着,未来气候变暖情景下,灌丛密度增加,凋落物输入量增大,可能导致无脊椎动物多样性增加。     

Effect of snow cover on seasonal changes in diet, habitat, and regional distribution of raptors that prey on small mammals in boreal zones of Fennoscandia

Seasonal changes in spatial distribution of search effort of birds that prey on small mammals were studied in two structurally different coniferous forest habitats in the northern boreal zone in SE Norway. During the season with snow cover both the proportion of Microtus relative to that of Clethrionomys in the predators' diet, and their use of a clear-cut relative to that of older forest were lower than during the snow-free season. This was related to a lower relative availability of prey ( Microtus agrestis and M. oeconomus ) in the clear-cut when the ground was snow-covered than when it was snow-free. Based on this local pattern I suggest the following explanation for differences in migratory strategy between raptors that prey on small mammals in Fennoscandian boreal zones: species that migrate to snow-free areas in winter are either adapted to hunt by the energetically expensive method of quartering in open grassland habitats, where prey ( Microtus ) availability is relatively low during periods with snow cover (hen harrier Circus cyaneus , short-eared owl Asio flammeus , and longeared owl A. otus ), or by sit-and-wait in open grassland and forest habitats, the latter with relatively high prey availability during periods with snow cover, but unable to locate concealed prey (kestrel Falco tinnuculus , common buzzard Buteo huteo , and roughlegged buzzard B. lagopus ). In contrast, species that remain in areas with permanent snow cover during winter use the energetically cheap sit-and-wait tactic, and are able to hunt in closed forest habitat and localize concealed prey (the remaining owl species). Interspecific differences in prey availability as determined by hunting habitat and hunting mode is probably more important in shaping the migration patterns of Fennoscandian owls than is nest site availability.     

雪被期川西高山林线交错带两种地被物凋落物分解与土壤动物多样性

以针叶林代表性地被植物锦丝藓和高山冷蕨为研究对象,采用凋落物分解网袋法,研究了高山林线交错带(暗针叶林-林线-高山草甸)的锦丝藓植物残体、高山冷蕨凋落叶及混合凋落物经过一个雪被期分解后的质量损失与土壤动物群落结构特征.结果表明: 雪被期林线交错带上两种地被物的质量损失率在高山草甸最大,锦丝藓表现更为显著,两种凋落物混合促进了分解过程且在林线上表现尤为显著.在交错带凋落物中共获取土壤动物968头,隶属于5纲10目35科,优势类群以弹尾目和蜱螨目为主.在林线上凋落物中获得的土壤动物个体数和类群数高于高山草甸和暗针叶林.典范对应分析(CCA)表明,土壤动物类群与雪被期平均温度关系最为密切,特有物种如等翅目和地蜈蚣目仅在暗针叶林出现,半翅目和啮目仅在高山草甸出现.地被物种类对土壤动物多样性的影响在暗针叶林和高山草甸大于林线.多元回归分析表明,日平均温度和雪被厚度能够解释凋落物质量损失率变异的30.8%,而土壤动物因子能解释质量损失率变异的8.3%,它们共同解释质量损失率变异的34.1%.雪被是影响高山两种地被物凋落物分解的最关键因子.     

Effects of small mammals and vertebrate predators on vegetation in the Chilean semiarid zone

 We monitored the cover and seed bank response of shrubs, perennial herbs, and ephemeral plants to experimental exclusion of both the principal rodent herbivore, Octodon degus, and its vertebrate predators from 1989 to 1994 in a semiarid Chilean mediterranean site. Although both richness and species composition of the plant community at the study site were largely determined by abiotic factors (mainly rainfall and soil nutrients), predator and herbivore exclusion had significant effects on the relative abundance of several plant species. Experimental exclusion of herbivores was associated with increased cover of some shrubs and a perennial grass, and decreased cover and seed densities of several ephemerals, especially those exotic or restricted to areas underneath shrubs. Herbivores apparently reduced shrubs through browsing and indirectly affected herb cover and seed densities by opening up areas under shrubs and/or modifying physical and chemical conditions of the soil. Plant responses to predator exclusion were less clear. Nevertheless, higher cover of some shrubs and ephemerals in the presence of predators suggests tritrophic effects through changes in small mammal densities and/or foraging behavior. Received: 22 April 1996 / Accepted: 14 August 1996     

不同郁闭度控制下马尾松（Pinus massoniana）人工林土壤动物群落特征

采用郁闭度控制方法,形成马尾松人工林郁闭度梯度(0.5,0.6,0.7,0.8,0.9)试验样地,研究不同郁闭度下土壤动物群落特征。运用手捡法、Tullgren法和Baermann法进行土壤动物群落调查。结果显示,1)共捕获土壤动物8 860只,隶属于4门11纲25目111科,其中大型土壤动物589只,以蜚蠊、疣和康叭为优势类群;中小型土壤动物8271只,以等节和丽甲螨为优势类群。2)大型土壤动物以杂食性为主,杂食性在0.9郁闭度显著增加,捕食性显著减少;中小型土壤动物以菌食和腐食性为主,腐食性土壤动物随郁闭度增大逐渐增加,菌食性逐渐减少。中小型捕食性土壤动物在郁闭度0.5—0.7显著增加,0.7—0.9无显著变化。3)大型土壤动物仅5—10 cm土层类群数在0.9郁闭度显著增加;中小型土壤动物总个体数及枯落物层个体数、5—10 cm土层类群数显著增加(0.5—0.7)后减少(0.7—0.9);中小型土壤动物总类群数在郁闭度0.5—0.6显著增加,枯落层类群数在郁闭度0.5—0.8显著增加,0.8—0.9显著减少。4)大型、中小型土壤动物多样性在土层中差异显著。中小型土壤动物Simpson优势度指数随郁闭度增大而减小,Shannon-Wiener多样性指数、Pielou均匀性指数则显著增大,Margalef丰富度指数先显著增高(0.5—0.6)后趋于平稳(0.6—0.9);大型土壤动物Jaccard相似性指数低于中小型。5)CCA分析表明,不同类群土壤动物对环境因子响应不同,郁闭度、含水量、有机质及全P对土壤动物类群影响显著。研究表明,0.7郁闭度马尾松人工林下土壤动物优势度、丰富度适中,林下植被恢复情况较好,该郁闭度可能更有利于土壤动物多样性和群落稳定性。     

Skink and invertebrate abundance in relation to vegetation, rabbits and predators in a New Zealand dryland ecosystem

We explored the relationships between ground vegetation, ground fauna (native skinks and invertebrates), rabbits, and predators in a modified New Zealand dryland ecosystem. We hypothesised that vegetation cover would provide habitat for ground fauna. We also hypothesised that rabbits (Oryctolagus cuniculus) would reduce the abundance of these fauna by reducing vegetation, and by providing prey for mammalian predators (cats Felis catus and ferrets Mustela putorius) that consume ground fauna as secondary prey. We measured these variables at 30 sites across three pastoral properties in the South Island in 1996 and 2002. There were mostly positive relationships between vegetation ground cover and fauna captures in pitfall traps. Relatively few beetles and caterpillars were caught where cover was less than 80%, no millipedes were caught where cover was less than 70%, and few spiders and mostly no skinks, crickets, flies or slugs were caught where vegetation cover was less than 50%. Most grasshoppers were caught where cover ranged from 30 to 80%. Faunal species richness was also positively related to cover. This supports our hypothesis that ground vegetation provides habitat for skinks and invertebrates in this ecosystem. The introduction of rabbit haemorrhagic disease in 1997 provided a natural experiment to test the hypothesised indirect effects of rabbits on ground fauna. Declines in rabbits varied between properties, and vegetation cover and predator abundance changed according to the magnitude of these declines. However, skink and invertebrate abundance did not track these changes as expected, but instead varied more or less consistently between properties. Some fauna increased (skink captures quadrupled and cricket captures nearly doubled), others declined (flies, caterpillars and spiders), and some did not change (beetles, millipedes, slugs and grasshoppers, and faunal species richness and diversity). Therefore, rabbits, predators and vegetation did not affect changes in skinks and invertebrates in consistent ways. The dynamics of ground fauna are likely to be more influenced by factors other than those we measured.     

Snow-induced changes in dwarf birch chemistry increase moth larval growth rate and level of herbivory

Changes in snow cover might influence arctic ecosystems to the same extent as increased temperatures. Although the duration of snow cover is generally expected to decrease in the future as a result of global warming, the amounts of snow might increase in arctic areas where much of the elevated precipitation will fall as snow. We examined the effects of an increased snow cover, as a result of a snow fence treatment, on soil nitrogen mineralization, plant phenology, plant chemistry (nitrogen and potential defense compounds), the level of invertebrate herbivory, and performance of invertebrate herbivores in an arctic ecosystem, using dwarf birch (Betula nana) and the autumnal moth (Epirrita autumnata) as study organisms. An enhanced and prolonged snow cover increased the level of herbivory on dwarf birch leaves. Larvae feeding on plants that had experienced enhanced snow cover grew faster and pupated earlier than larvae fed with plant material from control plots, indicating that plants from enhanced snow-lie plots produce higher-quality food to herbivores. The increased larval growth rate was strongly correlated with higher leaf nitrogen concentration in plants subjected to snow manipulation, and also to certain phenolic acids. Snow manipulation did not change net nitrogen mineralization rates in the soil or total carbon concentration in leaves, but it altered the within-season fluctuating pattern of leaf phenolic compounds. This study demonstrates a positive relationship between increased snow cover and level of herbivory on deciduous shrubs, thus proposing a negative feedback on the climate-induced dwarf shrub expansion in arctic areas.     

Nonlinear responses of wolverine populations to declining winter snowpack

Understanding the population-level impacts of climate change is critical for effectively managing ecosystems. Predators are important components of many systems because they provide top−down control of community structure. Ecological theory suggests that these species could be particularly susceptible to climate change because they generally occur at low densities and have resource-limited populations. Yet, our understanding of climate-change impacts on predators is hindered by the difficulty in assessing complex, nonlinear dynamics over the large spatial scales necessary to depict a species’ general response to abiotic forcing. Here we use fur-return data to characterize population dynamics of a snow-adapted carnivore, the wolverine, across most of its North American range. Using novel modeling techniques, we simultaneously measured the impact of winter snowpack on wolverine dynamics across critical thresholds in snowpack depth and two domains of population growth. Winter snowpack declined from 1970 to 2004 in nearly the entire region studied, concordant with increases in Northern Hemisphere temperature anomalies. Fur returns have declined in many areas; our models show that snowpack has strong, nonlinear effects on wolverine population dynamics. Importantly, wolverine harvests dropped the fastest in areas where snowpack declined most rapidly and also where snowpack had the greatest effect on population dynamics. Moreover, declining snow cover appears to drive trends in wolverine population synchrony, with important implications for overall persistence. These results illustrate the vulnerability and complex responses of predator populations to climate change. We also suggest that declining snowpack may be an important and hitherto little-analyzed mechanism through which climate change alters high-latitude ecosystems.