Browsing by Subject "FUNCTIONAL TRAITS"

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  • Oksanen, Otto; Zliobaite, Indre; Saarinen, Juha; Lawing, A. Michelle; Fortelius, Mikael (2019)
    Aim The links between geo- and biodiversity, postulated by Humboldt, can now be made quantitative. Species are adapted to their environments and interact with their environments by having pertinent functional traits. We aim to improve global ecometric models using functional traits for estimating palaeoclimate and apply models to Pleistocene fauna for palaeoclimate interpretation. Location Global at present day, Pleistocene of Europe for fossil data analysis. Taxa Artiodactyla, Perissodactyla, Proboscidea and Primates. Methods We quantify functional traits of large mammal communities and develop statistical models linking trait distributions to local climate at present day. We apply these models to the fossil record, survey functional traits, and quantitatively estimate climates of the past. This approach to analysing functional relationships between faunal communities and their environments is called ecometrics. Results and main conclusions Here, we present new global ecometric models for estimating mean annual and minimum temperature from dental traits of present day mammalian communities. We also present refined models for predicting net primary productivity. Using dental ecometric models, we produce palaeoclimate estimates for 50 Pleistocene fossil localities in Europe and show that the estimates are consistent with trends derived from other proxies, especially for minimum temperatures, which we hypothesize to be ecologically limiting. Our new temperature models allow us to trace the distribution of freezing and non-freezing ecosystems in the recent past, opening new perspectives on the evolution of cold-adaptive biota as the Pleistocene cooling progressed.
  • Jamoneau, Aurelien; Passy, Sophia I.; Soininen, Janne; Leboucher, Thibault; Tison-Rosebery, Juliette (2018)
    1. Understanding the mechanisms that drive beta diversity (i.e. beta-diversity), an important aspect of regional biodiversity, remains a priority for ecological research. beta-diversity and its components can provide insights into the processes generating regional biodiversity patterns. We tested whether environmental filtering or dispersal related processes predominated along the stream watercourse by analysing the responses of taxonomic and functional diatom beta-diversity to environmental and spatial factors. 2. We examined the variation in total beta-diversity and its components (turnover and nestedness) in benthic diatom species and ecological guilds (motile, planktonic, low-and high profile) with respect to watercourse position (up-, mid-and downstream) in 2,182 sites throughout France. We tested the effects of pure environmental and pure spatial factors on beta-diversity with partial Mantel tests. Environmental factors included eight physicochemical variables, while geographical distances between sites were used as spatial factors. We also correlated a and c-diversity, and the degree of nestedness (NODF metric) with environmental variables. 3. Total beta-diversity and its turnover component displayed higher values upstream than mid-and downstream. The nestedness component exhibited low values, even when NODF values increased from up-to downstream. Pure environmental factors were highly significant for explaining total beta-diversity and turnover regardless of watercourse position, but pure spatial factors were mostly significant mid-and downstream, with geographical distance being positively correlated with beta-diversity. Across sites, nutrient enrichment decreased turnover but increased the degree of nestedness. Motile and low profile diatoms comprised the most abundant guilds, but their beta-diversity patterns varied in an opposite way. The lowest guild beta-diversity was observed upstream for low profile species, and downstream for motile species. 4. In conclusion, environmental filtering seemed to play a major role in structuring metacommunities irrespective of site watercourse position. Filtering promoted strong turnover patterns, especially in disconnected upstream sites. The greater role of spatial factors mid-and downstream was consistent with mass effects rather than neutral processes because these sites had lower total beta-diversity than upstream sites. Motile species were most strongly affected by mass effects processes, whereas low profile species were primarily influenced by environmental conditions. Collectively, these findings suggest that partitioning of total beta-diversity into its components and the use of diatom ecological guilds provide a useful framework for assessing the mechanisms underlying metacommunity patterns along the stream watercourse.
  • Sun, Tao; Hobbie, Sarah E.; Berg, Björn; Zhang, Hongguang; Wang, Qingkui; Wang, Zhengwen; Hättenschwiler, Stephan (2018)
    Decomposition is a key component of the global carbon (C) cycle, yet current ecosystem C models do not adequately represent the contributions of plant roots and their mycorrhizae to this process. The understanding of decomposition dynamics and their control by traits is particularly limited for the most distal first-order roots. Here we followed decomposition of first-order roots and leaf litter from 35 woody plant species differing in mycorrhizal type over 6 years in a Chinese temperate forest. First-order roots decomposed more slowly (k = 0.11 +/- 0.01 years(-1)) than did leaf litter (0.35 +/- 0.02 years(-1)), losing only 35% of initial mass on average after 6 years of exposure in the field. In contrast to leaf litter, nonlignin root C chemistry (nonstructural carbohydrates, polyphenols) accounted for 82% of the large interspecific variation in first-order root decomposition. Leaf litter from ectomycorrhizal (EM) species decomposed more slowly than that from arbuscular mycorrhizal (AM) species, whereas first-order roots of EM species switched, after 2 years, from having slower to faster decomposition compared with those from AM species. The fundamentally different dynamics and control mechanisms of first-order root decomposition compared with those of leaf litter challenge current ecosystem C models, the recently suggested dichotomy between EM and AM plants, and the idea that common traits can predict decomposition across roots and leaves. Aspects of C chemistry unrelated to lignin or nitrogen, and not presently considered in decomposition models, controlled first-order root decomposition; thus, current paradigms of ecosystem C dynamics and model parameterization require revision.
  • Garzon, Marta Benito; Robson, T. Matthew; Hampe, Arndt (2019)
    Improving our understanding of species ranges under rapid climate change requires application of our knowledge of the tolerance and adaptive capacity of populations to changing environmental conditions. Here, we describe an emerging modelling approach, Delta TraitSDM, which attempts to achieve this by explaining species distribution ranges based on phenotypic plasticity and local adaptation of fitness-related traits measured across large geographical gradients. The collection of intraspecific trait data measured in common gardens spanning broad environmental clines has promoted the development of these new models - first in trees but now rapidly expanding to other organisms. We review, explain and harmonize the main findings from this new generation of models that, by including trait variation over geographical scales, are able to provide new insights into future species ranges. Overall, Delta TraitSDM predictions generally deliver a less alarming message than previous models of species distribution under new climates, indicating that phenotypic plasticity should help, to a considerable degree, some plant populations to persist under climate change. The development of Delta TraitSDMs offers a new perspective to analyse intraspecific variation in single and multiple traits, with the rationale that trait (co)variation and consequently fitness can significantly change across geographical gradients and new climates.
  • Thomas, H. J. D.; Bjorkman, A. D.; Myers-Smith, I. H.; Elmendorf, S. C.; Kattge, J.; Diaz, S.; Vellend, M.; Blok, D.; Cornelissen, J. H. C.; Forbes, B. C.; Henry, G. H. R.; Hollister, R. D.; Normand, S.; Prevéy, J. S.; Rixen, C.; Schaepman-Strub, G.; Wilmking, M.; Wipf, S.; Cornwell, W. K.; Beck, P. S. A.; Georges, D.; Goetz, S. J.; Guay, K. C.; Rüger, N.; Soudzilovskaia, N. A.; Spasojevic, M. J.; Alatalo, J. M.; Alexander, H. D.; Anadon-Rosell, A.; Angers-Blondin, S.; te Beest, M.; Berner, L. T.; Björk, R. G.; Buchwal, A.; Buras, A.; Carbognani, M.; Christie, K. S.; Collier, L. S.; Cooper, E. J.; Elberling, B.; Eskelinen, A.; Frei, E. R.; Grau, O.; Grogan, P.; Hallinger, M.; Heijmans, M. M. P. D.; Hermanutz, L.; Hudson, J. M. G.; Johnstone, J. F.; Hülber, K.; Iturrate-Garcia, M.; Iversen, C. M.; Jaroszynska, F.; Kaarlejarvi, E.; Kulonen, A.; Lamarque, L. J.; Lantz, T. C.; Lévesque, E.; Little, C. J.; Michelsen, A.; Milbau, A.; Nabe-Nielsen, J.; Nielsen, S. S.; Ninot, J. M.; Oberbauer, S. F.; Olofsson, J.; Onipchenko, V. G.; Petraglia, A.; Rumpf, S. B.; Shetti, R.; Speed, J. D. M.; Suding, K. N.; Tape, K. D.; Tomaselli, M.; Trant, A. J.; Treier, U. A.; Tremblay, M.; Venn, S. E.; Vowles, T.; Weijers, S.; Wookey, P. A.; Zamin, T. J.; Bahn, M.; Blonder, B.; van Bodegom, P. M.; Bond-Lamberty, B.; Campetella, G.; Cerabolini, B. E. L.; Chapin, F. S.; Craine, J. M.; Dainese, M.; Green, W. A.; Jansen, S.; Kleyer, M.; Manning, P.; Niinemets, Ü.; Onoda, Y.; Ozinga, W. A.; Peñuelas, J.; Poschlod, P.; Reich, P. B.; Sandel, B.; Schamp, B. S.; Sheremetiev, S. N.; de Vries, F. T. (2020)
    The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific relationships are confounded by trait variation within species. We test whether trait relationships extend to the cold extremes of life on Earth using the largest database of tundra plant traits yet compiled. We show that tundra plants demonstrate remarkably similar resource economic traits, but not size traits, compared to global distributions, and exhibit the same two dimensions of trait variation. Three quarters of trait variation occurs among species, mirroring global estimates of interspecific trait variation. Plant trait relationships are thus generalizable to the edge of global trait-space, informing prediction of plant community change in a warming world.
  • Ovaskainen, Otso; Tikhonov, Gleb; Norberg, Anna; Blanchet, F. Guillaume; Duan, Leo; Dunson, David; Roslin, Tomas; Abrego, Nerea (2017)
    Community ecology aims to understand what factors determine the assembly and dynamics of species assemblages at different spatiotemporal scales. To facilitate the integration between conceptual and statistical approaches in community ecology, we propose Hierarchical Modelling of Species Communities (HMSC) as a general, flexible framework for modern analysis of community data. While non-manipulative data allow for only correlative and not causal inference, this framework facilitates the formulation of data-driven hypotheses regarding the processes that structure communities. We model environmental filtering by variation and covariation in the responses of individual species to the characteristics of their environment, with potential contingencies on species traits and phylogenetic relationships. We capture biotic assembly rules by species-to-species association matrices, which may be estimated at multiple spatial or temporal scales. We operationalise the HMSC framework as a hierarchical Bayesian joint species distribution model, and implement it as R-and Matlab-packages which enable computationally efficient analyses of large data sets. Armed with this tool, community ecologists can make sense of many types of data, including spatially explicit data and time-series data. We illustrate the use of this framework through a series of diverse ecological examples.
  • Abrego, Nerea; Norberg, Anna; Ovaskainen, Otso (2017)
    1. The identification of traits that influence the responses of the species to environmental variation provides a mechanistic perspective on the assembly processes of ecological communities. While much research linking functional ecology with assembly processes has been conducted with animals and plants, the development of predictive or even conceptual frameworks for fungal functional community ecology remains poorly explored. Particularly, little is known about the contribution of traits to the occurrences of fungal species under different environmental conditions. 2. Wood-inhabiting fungi are known to strongly respond to habitat disturbance, and thus provide an interesting case study for investigating to what extent variation in occurrence patterns of fungi can be related to traits. We apply a trait-based joint species distribution model to a data set consisting of fruit-body occurrence data on 321 wood-inhabiting fungal species collected in 22 460 dead wood units from managed and natural forest sites. 3. Our results show that environmental filtering plays a big role on shaping wood-inhabiting fungal communities, as different environments held different communities in terms of species and trait compositions. Most importantly, forest management selected against species with large and long-lived fruit-bodies as well as late decayers, and promoted the occurrences of species with small fruit-bodies and early decayers. A strong phylogenetic signal in the data suggested the existence of also some other functionally important traits than the ones we considered. 4. We found that those species groups that were more prevalent in natural conditions had more associations to other species than species groups that were tolerant to or benefitted from forest management. Therefore, the changes that forest management causes on wood-inhabiting fungal communities influence ecosystem functioning through simplification of interactive associations among the fungal species. 5. Synthesis. Our results show that functional traits are linked to the responses of wood-inhabiting fungi to variation in their environment, and thus environmental changes alter ecosystem functions via promoting or reducing species with different fruit-body types. However, further research is needed to identify other functional traits and to provide conclusive evidence for the adaptive nature of the links from traits to occurrence patterns found here.
  • Li, Xuefei; Schmid, Bernhard; Wang, Fei; Paine, C. E. Timothy (2016)
    Growth rates are of fundamental importance for plants, as individual size affects myriad ecological processes. We determined the factors that generate variation in RGR among 14 species of trees and shrubs that are abundant in subtropical Chinese forests. We grew seedlings for two years at four light levels in a shade-house experiment. We monitored the growth of every juvenile plant every two weeks. After one and two years, we destructively harvested individuals and measured their functional traits and gas-exchange rates. After calculating individual biomass trajectories, we estimated relative growth rates using nonlinear growth functions. We decomposed the variance in log(RGR) to evaluate the relationships of RGR with its components: specific leaf area (SLA), net assimilation rate (NAR) and leaf mass ratio (LMR). We found that variation in NAR was the primary determinant of variation in RGR at all light levels, whereas SLA and LMR made smaller contributions. Furthermore, NAR was strongly and positively associated with area-based photosynthetic rate and leaf nitrogen content. Photosynthetic rate and leaf nitrogen concentration can, therefore, be good predictors of growth in woody species.
  • Legay, Nicolas; Clément, Jean-Christophe; Grassein, Fabrice; Lavorel, Sandra; Lemauviel-Lavenant , S; Personeni, Eleanor; Poly, Frank; Pommier, T; Robson, Thomas Matthew; Mouhamadou , B; Binet, M-N (2020)
    Relationships between plants and nitrogen-related microbes may vary with plant growth. We investigated these dynamic relationships over three months by analyzing plant functional traits (PFT), arbuscular mycorrhizal fungal (AMF) colonization, potential N mineralization (PNM), potential nitrification (PNA) and denitrification activities (PDA) in Dactylis glomerata cultures. D. glomerata recruited AMF during early growth, and thereafter maintained a constant root colonization intensity. This may have permitted high enough plant nutrient acquisition over the three months as to offset reduced soil inorganic N. PFT changed with plant age and declining soil fertility, resulting in higher allocation to root biomass and higher root C:N ratio. Additional to root AMF presence, PR' changes may have favored denitrification over mineralization through changes in soil properties, particularly increasing the quality of the labile carbon soil fraction. Other PFT changes, such as N uptake, modified the plants' ability to compete with bacterial groups involved in N cycling. (C) 2020 Elsevier Ltd and British Mycological Society. All rights reserved.
  • Stockwell, Jason D.; Doubek, Jonathan P.; Adrian, Rita; Anneville, Orlane; Carey, Cayelan C.; Carvalho, Laurence; Domis, Lisette de Senerpont; Dur, Gaël; Frassl, Marieke A.; Grossart, Hans-Peter; Ibelings, Bas W.; Lajeunesse, Marc J.; Lewandowska, Aleksandra; Llames, María E.; Matsuzaki, Shin-Ichiro S.; Nodine, Emily R.; Noges, Peeter; Patil, Vijay P.; Pomati, Francesco; Rinke, Karsten; Rudstam, Lars G.; Rusak, James A.; Salmaso, Nico; Seltmann, Christian T.; Straile, Dietmar; Thackeray, Stephen J.; Thiery, Wim; Urrutia-Cordero, Pablo; Venail, Patrick; Verburg, Piet; Woolway, R. Iestyn; Zohary, Tamar; Andersen, Mikkel R.; Bhattacharya, Ruchi; Hejzlar, Josef; Janatian, Nasime; Kpodonu, Alfred T. N. K.; Williamson, Tanner J.; Wilson, Harriet L. (2020)
    In many regions across the globe, extreme weather events such as storms have increased in frequency, intensity, and duration due to climate change. Ecological theory predicts that such extreme events should have large impacts on ecosystem structure and function. High winds and precipitation associated with storms can affect lakes via short-term runoff events from watersheds and physical mixing of the water column. In addition, lakes connected to rivers and streams will also experience flushing due to high flow rates. Although we have a well-developed understanding of how wind and precipitation events can alter lake physical processes and some aspects of biogeochemical cycling, our mechanistic understanding of the emergent responses of phytoplankton communities is poor. Here we provide a comprehensive synthesis that identifies how storms interact with lake and watershed attributes and their antecedent conditions to generate changes in lake physical and chemical environments. Such changes can restructure phytoplankton communities and their dynamics, as well as result in altered ecological function (e.g., carbon, nutrient and energy cycling) in the short- and long-term. We summarize the current understanding of storm-induced phytoplankton dynamics, identify knowledge gaps with a systematic review of the literature, and suggest future research directions across a gradient of lake types and environmental conditions.
  • Sitzia, T.; Campagnaro, T.; Kotze, David Johannes; Nardi, S.; Ertani, A. (2018)
    The abandonment of agricultural use is a common driver of spontaneous reforestation by alien trees. The N-fixing black locust (Robinia pseudoacacia L.) is a major alien invader of old fields in Europe. Here we show that canopy dominance by this tree may filter the frequency distribution of plant functional traits in the understory of secondary woodlands. Higher soil C/N ratio and available P are associated with black locust stands, while higher soil phenols associate with native tree stands. These environmental effects result in differences in understory flowering periods, reproduction types and life forms. Our findings emphasize the effect of a major alien tree on functional plant trait composition in the early stages of spontaneous reforestation of abandoned lands, implying the development of a novel forest ecosystem on a large geographical scale.
  • Burner, Ryan C.; Stephan, Jorg G.; Drag, Lukas; Birkemoe, Tone; Muller, Joerg; Snäll, Tord; Ovaskainen, Otso; Potterf, Maria; Siitonen, Juha; Skarpaas, Olav; Doerfler, Inken; Gossner, Martin M.; Schall, Peter; Weisser, Wolfgang W.; Sverdrup-Thygeson, Anne (2021)
    Aim The aim of this study was to investigate the role of traits in beetle community assembly and test for consistency in these effects among several bioclimatic regions. We asked (1) whether traits predicted species' responses to environmental gradients (i.e. their niches), (2) whether these same traits could predict co-occurrence patterns and (3) how consistent were niches and the role of traits among study regions. Location Boreal forests in Norway and Finland, temperate forests in Germany. Taxon Wood-living (saproxylic) beetles. Methods We compiled capture records of 468 wood-living beetle species from the three regions, along with nine morphological and ecological species traits. Eight climatic and forest covariates were also collected. We used Bayesian hierarchical joint species distribution models to estimate the influence of traits and phylogeny on species' niches. We also tested for correlations between species associations and trait similarity. Finally, we compared species niches and the effects of traits among study regions. Results Traits explained some of the variability in species' niches, but their effects differed among study regions. However, substantial phylogenetic signal in species niches implies that unmeasured but phylogenetically structured traits have a stronger effect. Degree of trait similarity was correlated with species associations but depended idiosyncratically on the trait and region. Species niches were much more consistent-widespread taxa often responded similarly to an environmental gradient in each region. Main conclusions The inconsistent effects of traits among regions limit their current use in understanding beetle community assembly. Phylogenetic signal in niches, however, implies that better predictive traits can eventually be identified. Consistency of species niches among regions means niches may remain relatively stable under future climate and land use changes; this lends credibility to predictive distribution models based on future climate projections but may imply that species' scope for short-term adaptation is limited.
  • Forey, Estelle; Langlois, Estelle; Lapa, Gauthier; Korboulewsky, Nathalie; Robson, T. Matthew; Aubert, Michael (2016)
    Manipulating stand composition is an important management tool that foresters can use to affect the nature of forests and ecosystem processes. In mixed stands, interspecific interactions among trees can cause changes in tree performances. Nevertheless, these interactions are context dependent (cf. stress-gradient hypothesis, SGH). We thus investigated how intraspecific functional changes in leaf trait (19 traits) of European beech (Fagus sylvatica) were influenced by stand composition. We compared pure beech stands with four mixed stands containing from one to three additional tree species along a gradient of edaphic stress (gradient of soil water-holding capacity and rooting depth). First, we demonstrated that stand composition induced strong intraspecific leaf trait variation in beech for LDMC, LMA, phenolic compounds, leaf pH and magnesium concentration, suggesting higher nutrient acquisition by more diverse stands. Nevertheless, these results were modulated by edaphic stress. Mixed stands only conferred an advantage in relatively stressed sites (luvisol and leptosol). Besides, the addition of oak to beech stands had unexpected negative effects in sites with less severe stress (cambisol) as indicated by the null or positive LogRR of LMA, LDMC and phenolics. This study found that stand composition is an important though often-overlooked driver of intraspecific variability in leaf quality, and potentially reflects changes in beech tree physiology and productivity. Our results also suggest that positive interactions prevail in sites with stressful conditions. Such validation of the SGH is rare in natural or managed mature forests. Lastly, we strongly recommend that forest managers consider stand composition and abiotic factors when implementing forest growth models to improve their yield predictions.
  • Nutrient Network; Aakala, Tuomas; Makela, Annikki (2020)
    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.