David A. Wardle

Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden

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Publications (296)2027.19 Total impact

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    ABSTRACT: Pleurocarpous feather mosses host di-nitrogen (N2) fixing cyanobacteria, and this association serves as an important source of N input to late-successional natural boreal forests. However, little is known about how forest management affects feather mosses and their associated N2-fixation rates, or how these rates change during post-logging stand development. We established a chronosequence of 32 forest stands used for commercial wood production to better understand how stand development after clear-cutting drives changes in biomass and N2-fixation rates of the two dominant feather mosses, Pleurozium schreberi and Hylocomium splendens. These stands included eight replicate stands of each of four stand types: (1) recently clear-cut and newly planted stands (CC, 4 years); (2) pre-commercial thinning stands (PCT, 16 years); (3) first thinning stands (T1, 34 years); and (4) mature uncut forest (MF, 123 years), all dominated by Pinus sylvestris. We found that clear-cutting did not reduce moss biomass relative to the uncut forest. Further, biomass of P. schreberi (but not of H. splendens) increased twofold from CC stands to PCT stands, and remained high throughout the T1 stands. Di-nitrogen fixation capacity, determined as the amount of N fixed per unit moss mass, was ca. six and three times larger in PCT stands compared to the other stand types for P. schreberi and H. splendens respectively. Correlation analyses showed that N2-fixation capacity associated with both moss species increased with increasing Empetrum hermaphroditum biomass, and that N2-fixation capacity of P. schreberi declined with increasing NH4+ availability. Further, correlation analysis showed that N2-fixation capacity of H. splendens declined with increasing tree biomass and decreasing light transmission. The total amount of N fixed at the stand level was highest in the PCT stands (1.0 kg ha−1 year−1 of N), and was associated with both high moss biomass and high N2-fixation capacity. The contribution of N2-fixation to total N accrual per hectare during stand development was ca. 9%, and across the chronosequence N2 was fixed on average at rates of 0.4 kg ha−1 year−1. Our results show that N2-fixation rates in feather moss communities were promoted by the conditions at the PCT stands approximately 16 years after clear-cutting, while N2-fixation rates were lowest under conditions at the newly clear-cut and mature stands. Further, it suggests that mosses and associated N2-fixation can be important in maintaining a long-term N balance, and that this source of N input should be accounted for when modeling N balance in N-limited managed boreal forests.
    Forest Ecology and Management 07/2015; 347. DOI:10.1016/j.foreco.2015.03.017 · 2.67 Impact Factor
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    ABSTRACT: 1.Plant chemical and structural defense compounds are well known to impact upon herbivory of fresh leaves and influence decomposition rates after leaf senescence. A number of theories predict that alleviating nutrient limitation and reducing other environmental stressors will result in decreased production of plant chemical defenses.2.In this study, we measured plant defense properties (total polyphenols (TP), condensed tannins (CT) and lignin concentrations, and protein complexation capacity (PCC)) in both fresh and senesced plant leaves in a fully factorial N and P fertilization experiment set up at each of three elevations along an elevational gradient in Swedish subarctic tundra heath vegetation. Further, we performed a decomposition of variance analysis on community-weighted averages (CWA) of plant defense properties to determine the relative contributions of interspecific and intraspecific variation to the total variation observed in response to elevation and nutrient addition.3.We hypothesized that N fertilization would reduce plant defense properties and that this reduction would be greater at higher elevations, while the effects of P fertilization would have no effect at any elevation.4.At the community level, N addition reduced CT and PCC in both fresh and senesced leaves and TP in senesced leaves, while P addition had few effects, broadly in line with our hypothesis. The effects of N addition frequently varied with elevation, but in contrast to our hypothesis, said effects were strongest at the lowest elevations. The effects of N addition and the interactive effect of N with elevation were primarily driven by intraspecific, rather than interspecific, variation.5.Our findings suggest that as temperatures warm and N availability increases due to global climate change, secondary metabolites in subarctic heath vegetation will decline particularly within species. Our results highlight the need to consider the effects of both nutrient availability and temperature, and their interaction, in driving subarctic plant defense.This article is protected by copyright. All rights reserved.
    Functional Ecology 06/2015; DOI:10.1111/1365-2435.12493 · 4.86 Impact Factor
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    ABSTRACT: Biochar management has been proposed as a possible tool to mitigate anthropogenic CO2 emissions, and thus far its impacts in forested environments remain poorly understood. We conducted a large scale, replicated field experiment using 0.05 ha plots in the boreal region in Northern Sweden to evaluate how soil and vegetation properties and processes responded to biochar application and the disturbance associated with burying biochar in the soil. We employed a randomized block design, where biochar and soil mixing treatments were established in factorial combination (i.e. control, soil mixing-only, biochar-only, and biochar and soil mixing; n=6 plots of each). After two growing seasons, we found that biochar application enhanced net soil N mineralization rates and soil NH4+ concentrations regardless of the soil mixing treatment, but had no impact on the availability of NO3-, the majority of soil microbial community parameters, or soil respiration. Meanwhile, soil mixing enhanced soil NO3- concentrations, but had negative impacts on net N mineralization rates and several soil microbial community variables. Many of the effects of soil mixing on soil nutrient and microbial community properties were less extreme when biochar was also added. Biochar addition had almost no effects on vegetation properties (except for a small reduction in species richness of the ground layer vegetation), while soil mixing caused significant reductions in graminoid and total ground layer vegetation cover, and enhanced seedling survival rates of P. sylvestris, and seed germination rates for four tree species. Our results suggest that biochar application can serve as an effective tool to store soil C in boreal forests while enhancing NH4+ availability. They also suggest that biochar may serve as a useful complement to site preparation techniques that are frequently used in the boreal region, by enhancing soil fertility and reducing nutrient losses when soils are scarified during site preparation.This article is protected by copyright. All rights reserved.
    GCB Bioenergy 05/2015; DOI:10.1111/gcbb.12274 · 4.25 Impact Factor
  • Johan Asplund, David A. Wardle
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    ABSTRACT: Changes in the functional traits of the terricolous lichen Peltigera aphthosa with declining soil fertility during ecosystem retrogression were investigated. A well-documented retrogressive chronosequence of 28 forested islands in northern Sweden that differ greatly in fire history and which spans 5000 years was used. The abundance of cephalodia increased, indicative of higher N2-fixation rates resulting from lower N availability. Thallus δ13C values increased with ageing soils, in line with declining δ13C values of the humus substratum along this gradient. However, δ13C values were also driven by variation in factors that were at least partly independent of soil ageing. As such, δ13C values were mostly related to specific thallus mass (STM), possibly because a higher STM gives a thicker cortical layer and thus greater resistance to CO2 diffusion, leading to higher δ13C values. STM and other measured traits (i.e. thallus N, P, secondary compounds and water-holding capacity) were unresponsive to the gradient, despite these traits being very responsive to the same gradient in epiphytic lichen species.
    The Lichenologist 05/2015; 47(03):187-195. DOI:10.1017/S0024282915000092 · 1.61 Impact Factor
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    ABSTRACT: While there has been much interest in the relationships between traits of primary producers and composition of associated invertebrate consumer communities, our knowledge is largely based on studies from vascular plants, while other types of functionally important producers, such as lichens, have rarely been considered. To address how physiological traits of lichens drive community composition of invertebrates, we collected thalli from 27 lichens species from southern Norway and quantified the communities of associated springtails, mites and nematodes. For each lichen species we measured several thallus traits (i.e., concentration of nitrogen (N), phosphorus (P), pH, % water content at saturation (WC), and concentration of medullary and cortical carbon-based secondary compounds (CBSCs), and determined whether invertebrate communities were correlated to these traits among the 27 species. We also explored whether invertebrate communities differed among lichen groups, categorized according to nitrogen-fixing ability, growth form and substratum. Lichen traits explained up to 39% of the variation in abundances of major invertebrate groups. For many invertebrate groups, abundance was positively correlated to lichen N and P concentrations, N:P ratio, and WC, but had few relationships with CBSC concentrations. Diversity and taxonomic richness of invertebrate groups were sometimes also correlated to lichen N and N:P ratios. Nitrogen-fixing lichens showed higher abundance and diversity of some invertebrate groups than did non N-fixing lichens, but this emerged in part because most N-fixing lichens have a foliose growth form that benefits invertebrates, through improving the microclimate, independently of N concentration. Furthermore, invertebrate communities associated with terricolous lichens were determined more by their close proximity to the soil invertebrate pool than by lichen traits. Overall, our results reveal that differences between lichen species, in growth form and physiological traits, have a large impact on the invertebrate communities that live among the thalli. Different invertebrate groups show contrasting responses to traits that are indicative of thallus quality (nutrient concentrations), and thallus growth form is often an important determinant of the invertebrate community. Given the large diversity of lichen traits and growth forms that occur in many ecosystems, lichen-invertebrate communities may be an important contributor to overall community diversity in boreal forests.
    Ecology 03/2015; DOI:10.1890/14-1030.1 · 5.00 Impact Factor
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    ABSTRACT: The ‘home-field advantage’ (HFA) hypothesis predicts that plant litter is decomposed faster than expected underneath the plant from which it originates (‘home’) than underneath other plants (‘away’), because decomposer communities are specialized to break down litter from the plants they associate with. However, empirical evidence shows that the occurrence of HFA is highly variable, and the reasons for this are little understood.In our study we progress our understanding by investigating whether HFA is stronger for more recalcitrant litter types and under colder conditions and how soil properties and plant functional traits affect the magnitude and direction of HFA.In subarctic tundra in northern Sweden we set up a reciprocal transplant litter decomposition experiment along an elevational gradient where three highly contrasting vegetation types (heath, meadow and Salix) occur at all elevations, and where temperature decreases strongly with elevation. In this study, we used a litter bag approach where litters from each elevation × vegetation type combination were decomposed in all combinations of elevation × vegetation type. We also measured community-level plant functional traits, such as leaf and litter nutrient content. We determined soil biotic and abiotic properties, such as microbial biomass and soil nutrient content, in soil cores collected for each elevation × vegetation type combination.We found that mass loss increased with plant and litter nutrient content and with soil temperature. In contrast, the occurrence of HFA was limited in our study system, and its magnitude and direction could not be explained by vegetation type, elevation, plant traits or soil properties, despite these factors serving as powerful drivers of litter mass loss in our study.We conclude that although vegetation type and climate are major drivers of litter mass loss, they do not emerge as important determinants of HFA. Therefore, while rapid shifts in plant community composition or temperature due to global change are likely to influence litter mass loss directly by altering environmental conditions, plant trait spectra and litter quality, indirect effects of global change resulting from decoupling of specialist interactions between litter and decomposer communities appears to be of less importance.This article is protected by copyright. All rights reserved.
    Functional Ecology 02/2015; DOI:10.1111/1365-2435.12421 · 4.86 Impact Factor
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    ABSTRACT: Relative to vascular plants, little is known about what factors control bryophyte communities or how they respond to successional and environmental changes. Bryophytes are abundant in boreal forests, thus changes in moss community composition and functional traits (for example, moisture and nutrient content; rates of photosynthesis and respiration) may have important consequences for ecosystem processes and microfaunal communities. Through synthesis of previous work and new analyses integrating new and published data from a long term successional gradient in the boreal forest of northern Sweden, we provide a comprehensive view of the biotic factors (for example, vascular plant productivity, species composition, and diversity) and abiotic factors (for example, soil fertility and light transmission) that impact the moss community. Our results show that different aspects of the moss community (that is, composition, functional traits, moss-driven processes, and associated invertebrate fauna) respond to different sets of environmental variables, and that these are not always the same variables as those that influence the vascular plant community. Measures of moss community composition and functional traits were primarily influenced by vascular plant community composition and productivity. This suggests that successional shifts in abiotic variables, such as soil nutrient levels, indirectly affect the moss community via their influence on vascular plant community characteristics, whereas direct abiotic effects are less important. Among the moss-driven processes, moss litter decomposition and moss productivity were mainly influenced by biotic variables (notably the community characteristics of both vascular plants and mosses), whereas moss functional traits (primarily specific leaf area and tissue nutrient concentrations) also were important in explaining moss di-nitrogen-fixation rates. In contrast, both abiotic and biotic variables were important drivers of moss microfaunal community structure. Taken together, our results show which abiotic and biotic factors impact mosses and their associated organisms, and thus highlight that multiple interacting factors need to be considered to understand how moss communities, associated food webs, and the ecosystem processes they influence will respond to environmental change.
    Ecosystems 01/2015; 18:154-169. DOI:10.1007/s10021-014-9819-8 · 3.53 Impact Factor
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    ABSTRACT: Questions: It remains unresolved why, despite the obvious functional importance of leaves and roots, co-existing plant species can display highly contrasting biomass distributions of these organs. Building on the ‘functional equilibrium’ hypothesis, we hypothesize that co-existing species can each achieve balanced resource acquisition above vs below ground by trading off the biomass vs morphology of structures responsible for resource acquisition, i.e. leaves and fine roots. Methods: We tested this hypothesis in a natural field setting by measuring plant above- and below-ground biomass and morphological traits associated with resource uptake – specific leaf area (SLA) and specific root length (SRL) – of 18 dominant angiosperm species from a sub-alpine plant community. Location: New Zealand South Island. Results: We found a significant negative relationship between the species leaf mass to fine root mass ratio and the SLA to SRL ratio when we considered eudicot species only. The SLA to SRL ratio and plant size explained 31% and 34% of the total variation in the species leaf to fine root mass ratio respectively, and 45% when used in combination (P < 0.05 in all cases). Within a given plant size, 90% of the variation among species in total leaf area was due to differences in SLA, whereas variation in the fine root mass fraction was responsible for 71% of the variation among species in fine root length. Conclusions: In support of our hypothesis, part of the difference between co-occurring species in leaf and fine root biomass distribution could be explained by the variable morphologies of these organs as well as variation in plant size, independent of the plant economic strategy. We expect that this outcome may result from environmental and evolutionary constraints on plant species-average traits, as well as plastic responses to local environmental conditions. These findings help explain why a diversity of strategies for achieving balanced resource acquisition can co-exist within a single plant community.
    Journal of Vegetation Science 01/2015; DOI:10.1111/jvs.12259 · 3.37 Impact Factor
  • David A Wardle
    Nature 12/2014; 516(7529):37. DOI:10.1038/516037a · 42.35 Impact Factor
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    ABSTRACT: Boreal forest soils store a major proportion of the global terrestrial carbon (C) and below-ground inputs contribute as much as above-ground plant litter to the total C stored in the soil. A better understanding of the dynamics and drivers of root-associated fungal communities is essential to predict long-term soil C storage and climate feedbacks in northern ecosystems.We used 454-pyrosequencing to identify fungal communities across fine-scaled soil profiles in a 5000 yr fire-driven boreal forest chronosequence, with the aim of pinpointing shifts in fungal community composition that may underlie variation in below-ground C sequestration.In early successional-stage forests, higher abundance of cord-forming ectomycorrhizal fungi (such as Cortinarius and Suillus species) was linked to rapid turnover of mycelial biomass and necromass, efficient nitrogen (N) mobilization and low C sequestration. In late successional-stage forests, cord formers declined, while ericoid mycorrhizal ascomycetes continued to dominate, potentially facilitating long-term humus build-up through production of melanized hyphae that resist decomposition.Our results suggest that cord-forming ectomycorrhizal fungi and ericoid mycorrhizal fungi play opposing roles in below-ground C storage. We postulate that, by affecting turnover and decomposition of fungal tissues, mycorrhizal fungal identity and growth form are critical determinants of C and N sequestration in boreal forests.
    New Phytologist 12/2014; 205(4). DOI:10.1111/nph.13208 · 6.55 Impact Factor
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    ABSTRACT: Invasive exotic plant species effects on soil biota and processes in their new range can promote or counteract invasions via changed plant-soil feedback interactions to themselves or to native plant species. Recent meta-analyses reveale that soil influenced by native and exotic plant species is affecting growth and performance of natives more strongly than exotics. However, the question is how uniform these responses are across contrasting life forms. Here, we test the hypothesis that life form matters for effects on soil and plant-soil feedback. In a meta-analysis we show that exotics enhanced C cycling, numbers of meso-invertebrates and nematodes, while having variable effects on other soil biota and processes. Plant effects on soil biota and processes were not dependent on life form, but patterns in feedback effects of natives and exotics were dependent on life form. Native grasses and forbs caused changes in soil that subsequently negatively affected their biomass, whereas native trees caused changes in soil that subsequently positively affected their biomass. Most exotics had neutral feedback effects, although exotic forbs had positive feedback effects. Effects of exotics on natives differed among plant life forms. Native trees were inhibited in soils conditioned by exotics, whereas native grasses were positively influenced in soil conditioned by exotics. We conclude that plant life form matters when comparing plant-soil feedback effects both within and between natives and exotics. We propose that impact analyses of exotic plant species on the performance of native plant species can be improved by comparing responses within plant life form.
    Biological Invasions 12/2014; 16(12). DOI:10.1007/s10530-014-0685-2 · 2.72 Impact Factor
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    ABSTRACT: Some communities are susceptible to invasions and some are not. Why? Elton suggested in 1958 that the ability of the community to withstand invading species – its biotic resistance – depends on the number of resident species. Later contributors have emphasized the habitat's ability to support species, as well as the contribution of individual species to the resistance. In this study we use information from 184 introductions of Arctic char into Swedish lakes to study both abiotic and biotic aspects of the resident community's ability to resist introductions. We find that the best model included the proportion of forest cover and the proportion of agricultural land cover in the watershed in combination with the presence versus absence of northern pike. Thus, the most important biotic factor to explain the outcome of introductions of Arctic char is the presence of northern pike, a large piscivore. This means that one single species explains the outcome of the introductions better than does the species richness or the saturation level of the community.
    Oikos 12/2014; DOI:10.1111/oik.01700 · 3.56 Impact Factor
  • David A Wardle, Björn D Lindahl
    Science 11/2014; 346(6213):1052-3. DOI:10.1126/science.aaa1185 · 31.48 Impact Factor
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    Paul Kardol, Jonathan R De Long, David A Wardle
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    ABSTRACT: Predicting how plants will respond to global warming necessitates understanding of local plant adaptation to temperature. Temperature may exert selective effects on plants directly, and also indirectly through environmental factors that covary with temperature, notably soil properties. However, studies on the interactive effects of temperature and soil properties on plant adaptation are rare, and the role of abiotic versus biotic soil properties in plant adaptation to temperature remains untested. We performed two growth chamber experiments using soils and Bistorta vivipara bulbil ecotypes from a subarctic elevational gradient (temperature range: ±3(°)C) in northern Sweden to disentangle effects of local ecotype, temperature, and biotic and abiotic properties of soil origin on plant growth. We found partial evidence for local adaption to temperature. Although soil origin affected plant growth, we did not find support for local adaptation to either abiotic or biotic soil properties, and there were no interactive effects of soil origin with ecotype or temperature. Our results indicate that ecotypic variation can be an important driver of plant responses to the direct effects of increasing temperature, while responses to covariation in soil properties are of a phenotypic, rather than adaptive, nature.
    Royal Society Open Science 10/2014; 1(3). DOI:10.1098/rsos.140141
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    ABSTRACT: Aims This study explores soil nutrient cycling processes and microbial properties for two contrasting vegetation types along an elevational gradient in subarctic tundra to improve our understanding of how temperature influences nutrient availability in an ecosystem predicted to be sensitive to global warming. Methods We measured total amino acid (Amino-N), mineral nitrogen (N) and phosphorus (P) concentrations, in situ net N and P mineralization, net Amino-N consumption, and microbial biomass C, N and P in both heath and meadow soils across an elevational gradient near Abisko, Sweden. Results For the meadow, NH4+ concentrations and net N mineralization were highest at high elevations and microbial properties showed variable responses; these variables were largely unresponsive to elevation for the heath. Amino-N concentrations sometimes showed a tendency to increase with elevation and net Amino-N consumption was often unresponsive to elevation. Overall, PO4-P concentrations decreased with elevation and net P immobilization mostly occurred at lower elevations; these effects were strongest for the heath. Conclusions Our results reveal that elevation-associated changes in temperature can have contrasting effects on the cycling of N and P in subarctic soils, and that the strength and direction of these effects depend strongly on dominant vegetation type.
    Plant and Soil 10/2014; 383(1-2). DOI:10.1007/s11104-014-2179-5 · 3.24 Impact Factor
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    ABSTRACT: This study investigates how burrow-nesting, colonial seabirds structure the spatial patterns of soil and plant properties (including soil and leaf N) and tests whether burrow density drives these spatial patterns within each of six individual islands that vary greatly in burrow density. Within individual islands, we compared semivariograms (SVs) with and without burrows as a spatial trend. We also used SVs to describe and compare the spatial patterns among islands for each of 16 soil and plant variables. Burrow density within a single island was only important in determining spatial structuring in one-fifth of the island-variable combinations tested. Among islands, some variables (i.e., soil pH, delta N-15, and compaction; microbial biomass and activity) achieved peak spatial variance on intermediate-density islands, while others (i.e., net ammonification, net nitrification, NH4 (+), NO3 (-)) became increasingly variable on densely burrowed islands. Burrow density at the within-island scale was far less important than expected. Seabirds and other ecosystem engineers whose activities (e.g., nutrient subsidies, soil disturbance) influence multiple spatial scales can increase spatial heterogeneity even at high densities, inconsistent with a "hump-shaped" relationship between resource availability and heterogeneity.
    Plant and Soil 10/2014; 383(1-2):139-153. DOI:10.1007/s11104-014-2172-z · 3.24 Impact Factor
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    ABSTRACT: There has been growing recent use of elevational gradients as tools for assessing effects of temperature changes on vegetation properties, because these gradients enable temperature effects to be considered over larger spatial and temporal scales than is possible through conventional experiments. While many studies have explored the direct effects of temperature, the indirect effects of temperature through its long-term influence on soil abiotic or biotic properties remain essentially unexplored. We performed two climate chamber experiments using soils from a subarctic elevational gradient in Abisko, Sweden to investigate the direct effects of temperature, and indirect effects of temperature via soil legacies, on growth of two grass species. The soils were collected from each of two vegetation types (heath, dominated by dwarf shrubs, and meadow, dominated by graminoids and herbs) at each of three elevations. We found that plants responded to both the direct effect of temperature and its indirect effect via soil legacies, and that direct and indirect effects were largely decoupled. Vegetation type was a major determinant of plant responses to both the direct and indirect effects of temperature; responses to soils from increasing elevation were stronger and showed a more linear decline for meadow than for heath soils. The influence of soil biota on plant growth was independent of elevation, with a positive influence across all elevations regardless of soil origin for meadow soils but not for heath soils. Taken together, this means that responses of plant growth to soil legacy eff ects of temperature across the elevational gradient were driven primarily by soil abiotic, and not biotic, factors. These findings emphasize that vegetation type is a strong determinant of how temperature variation across elevational gradients impacts on plant growth, and highlight the need for considering both direct and indirect effects of temperature on plant responses to future climate change.
    Oikos 09/2014; 124(6). DOI:10.1111/oik.01764 · 3.56 Impact Factor
  • Lawrence R. Walker, David A. Wardle
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    ABSTRACT: Ecologists have studied plant succession for over a hundred years, yet our understanding of the nature of this process is incomplete, particularly in relation to its response to new human perturbations and the need to manipulate it during ecological restoration. We demonstrate how plant succession can be understood better when it is placed in the broadest possible temporal context. We further show how plant succession can be central to the development of a framework that integrates a spectrum of ecological processes, which occur over time scales ranging from seconds to millions of years. This novel framework helps us understand the impacts of human perturbations on successional trajectories, ecosystem recovery, and global environmental change.
    Trends in Ecology & Evolution 09/2014; 29(9). DOI:10.1016/j.tree.2014.07.002 · 15.35 Impact Factor
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    ABSTRACT: Fire has an important role for regeneration of many boreal forest tree species, and this includes both wildfire and prescribed burning following clear-cutting. Depending on the severity, fire can have a variety of effects on above-and below-ground properties that impact tree seedling establishment. Very little is known about the impacts of ground fire severity on post-fire seedling performance, or how the effects of fire severity interact with those of canopy structure. We conducted a full-factorial experiment that manipulated surface-burn severity (no burn; light, medium, or heavy burn; or scarification) and canopy (closed forest or open clear-cut) to reveal their interactive effects on ecophysiological traits of establishing broadleaf and conifer seedlings in a Swedish boreal forest. Medium and heavy surface burns increased seedling growth, photosynthesis, respiration, and foliar N and P concentrations, and these effects were most apparent in open clear-cuts. Growth rates of all species responded similarly to surface-burn treatments, although photosynthesis, foliar P, and specific leaf area were more responsive to burning treatments for broadleaf species than for conifers. Our study demonstrates that the positive impacts of fire on tree seedling physiology are dependent on a minimum severity threshold and are more effective when combined with clear-cutting.
    Canadian Journal of Forest Research 09/2014; 44(9):1032-1041. DOI:10.1139/cjfr-2014-0112 · 1.66 Impact Factor

Publication Stats

20k Citations
2,027.19 Total Impact Points


  • 1998–2015
    • Swedish University of Agricultural Sciences
      • • Department of Forest Ecology and Management
      • • Faculty of Forest Sciences
      Uppsala, Uppsala, Sweden
  • 2013
    • Stanford University
      • Department of Biology
      Palo Alto, California, United States
  • 2011
    • University of California, Santa Cruz
      • Department of Ecology & Evolutionary Biology
      Santa Cruz, CA, United States
  • 2009
    • New Zealand Department of Conservation
      Wellington, Wellington, New Zealand
  • 2005
    • University of Canterbury
      • School of Biological Sciences
      Christchurch, Canterbury, New Zealand
    • University of Cambridge
      • Department of Plant Sciences
      Cambridge, ENG, United Kingdom
  • 2002–2005
    • University of Auckland
      • Department of Physics
      Окленд, Auckland, New Zealand
  • 2003
    • Landcare Research
      Christchurch, Canterbury, New Zealand
  • 2001–2002
    • The University of Sheffield
      • Department of Animal and Plant Sciences
      Sheffield, England, United Kingdom
  • 2000
    • University of Helsinki
      • Department of Environmental Sciences
      Helsinki, Uusimaa, Finland
  • 1990–1993
    • The University of Calgary
      • Department of Biological Sciences
      Calgary, Alberta, Canada