Browsing by Subject "ecosystem function"

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  • Gustafsson, Camilla Maria; Norkko, Alf Mattias (2019)
    1. Aquatic plant meadows are important coastal habitats that sustain many ecosystem functions such as primary production and carbon sequestration. Currently, there is a knowledge gap in understanding which plant functional traits, for example, leaf size or plant height underlie primary production in aquatic plant communities. 2. To study how plant traits are related to primary production, we conducted a field survey in the Baltic Sea, Finland, which is characterized by high plant species and functional diversity. Thirty sites along an exposure gradient were sampled (150 plots), and nine plant morphological and chemical traits measured. The aim was to discern how community-weighted mean traits affect community production and whether this relationship changes along an environmental gradient using structural equation modelling (SEM). 3. Plant height had a direct positive effect on production along an exposure gradient (r = 0.33) and indirect effects through two leaf chemical traits, leaf δ15N and leaf δ13C (r = 0.24 and 0.18, respectively) resulting in a total effect of 0.28. In plant communities experiencing varying exposure, traits such as root N concentration and leaf δ15N had positive and negative effects on production, respectively. 4. Synthesis. Our results demonstrate that the relationship between aquatic plant functional traits and community production is variable and changes over environmental gradients. Plant height generally has a positive effect on community production along an exposure gradient, while the link between other traits and production changes in plant communities experiencing varying degrees of exposure. Thus, the underlying biological mechanisms influencing production differ in plant communities, emphasizing the need to resolve variability and its drivers in real-world communities. Importantly, functionally diverse plant communities sustain ecosystem functioning differently and
  • Griffiths, Jennifer R.; Kadin, Martina; Nascimento, Francisco J. A.; Tamelander, Tobias; Törnroos, Anna; Bonaglia, Stefano; Bonsdorff, Erik; Bruchert, Volker; Gårdmark, Anna; Järnström, Marie; Kotta, Jonne; Lindegren, Martin; Nordström, Marie C.; Norkko, Alf; Olsson, Jens; Weigel, Benjamin; Zydelis, Ramunas; Blenckner, Thorsten; Niiranen, Susa; Winder, Monika (2017)
    Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems, and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure and function are strongly affected by anthropogenic pressures; however, there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic-pelagic coupling processes (e.g., nutrient exchange and sedimentation of organic material) are to some extent quantifiable, but the magnitude and variability of biological processes are rarely assessed, preventing quantitative comparisons. Changing oxygen conditions will continue to have widespread effects on the processes that govern inorganic and organic matter exchange among habitats while climate change and nutrient load reductions may have large effects on organic matter sedimentation. Many biological processes (predation, bioturbation) are expected to be sensitive to anthropogenic drivers, but the outcomes for ecosystem function are largely unknown. We emphasize how improved empirical and experimental understanding of benthic-pelagic coupling processes and their variability are necessary to inform models that can quantify the feedbacks among processes and ecosystem responses to a changing world.
  • Thomas, H. J. D.; Myers-Smith, I. H.; Bjorkman, A. D.; Elmendorf, S. C.; Blok, D.; Cornelissen, J. H. C.; Forbes, B. C.; Hollister, R. D.; Normand, S.; Prevey, J. S.; Rixen, C.; Schaepman-Strub, G.; Wilmking, M.; Wipf, S.; Cornwell, W. K.; Kattge, J.; Goetz, S. J.; Guay, K. C.; Alatalo, J. M.; Anadon-Rosell, A.; Angers-Blondin, S.; Berner, L. T.; Bjork, R. G.; Buchwal, A.; Buras, A.; Carbognani, M.; Christie, K.; Collier, L. Siegwart; Cooper, E. J.; Eskelinen, A.; Frei, E. R.; Grau, O.; Grogan, P.; Hallinger, M.; Heijmans, M. M. P. D.; Hermanutz, L.; Hudson, J. M. G.; Huelber, K.; Iturrate-Garcia, M.; Iversen, C. M.; Jaroszynska, F.; Johnstone, J. F.; Kaarlejärvi, E.; Kulonen, A.; Lamarque, L. J.; Levesque, 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.; Semenchuk, P. R.; Soudzilovskaia, N. A.; Spasojevic, M. J.; Speed, J. D. M.; Tape, K. D.; te Beest, M.; Tomaselli, M.; Trant, A.; Treier, U. A.; Venn, S.; Vowles, T.; Weijers, S.; Zamin, T.; Atkin, O. K.; Bahn, M.; Blonder, B.; Campetella, G.; Cerabolini, B. E. L.; Chapin, F. S.; Dainese, M.; de Vries, F. T.; Diaz, S.; Green, W.; Jackson, R. B.; Manning, P.; Niinemets, U.; Ozinga, W. A.; Penuelas, J.; Reich, P. B.; Schamp, B.; Sheremetev, S.; van Bodegom, P. M. (2019)
    Aim Plant functional groups are widely used in community ecology and earth system modelling to describe trait variation within and across plant communities. However, this approach rests on the assumption that functional groups explain a large proportion of trait variation among species. We test whether four commonly used plant functional groups represent variation in six ecologically important plant traits. Location Tundra biome. Time period Data collected between 1964 and 2016. Major taxa studied 295 tundra vascular plant species. Methods We compiled a database of six plant traits (plant height, leaf area, specific leaf area, leaf dry matter content, leaf nitrogen, seed mass) for tundra species. We examined the variation in species-level trait expression explained by four traditional functional groups (evergreen shrubs, deciduous shrubs, graminoids, forbs), and whether variation explained was dependent upon the traits included in analysis. We further compared the explanatory power and species composition of functional groups to alternative classifications generated using post hoc clustering of species-level traits. Results Traditional functional groups explained significant differences in trait expression, particularly amongst traits associated with resource economics, which were consistent across sites and at the biome scale. However, functional groups explained 19% of overall trait variation and poorly represented differences in traits associated with plant size. Post hoc classification of species did not correspond well with traditional functional groups, and explained twice as much variation in species-level trait expression. Main conclusions Traditional functional groups only coarsely represent variation in well-measured traits within tundra plant communities, and better explain resource economic traits than size-related traits. We recommend caution when using functional group approaches to predict tundra vegetation change, or ecosystem functions relating to plant size, such as albedo or carbon storage. We argue that alternative classifications or direct use of specific plant traits could provide new insights for ecological prediction and modelling.