[en] There is considerable evidence that biodiversity promotes multiple ecosystem functions (multifunctionality), thus ensuring the delivery of ecosystem services important for human well-being. However, the mechanisms underlying this relationship are poorly understood, especially in natural ecosystems. We develop a novel approach to partition biodiversity effects on multifunctionality into three mechanisms and apply this to European forest data. We show that throughout Europe, tree diversity is positively related with multifunctionality when moderate levels of functioning are required, but negatively when very high function levels are desired. For two well-known mechanisms, 'complementarity' and 'selection', we detect only minor effects on multifunctionality. Instead a third, so far overlooked mechanism, the 'jack-of-all-trades' effect, caused by the averaging of individual species effects on function, drives observed patterns. Simulations demonstrate that jack-of-all-trades effects occur whenever species effects on different functions are not perfectly correlated, meaning they may contribute to diversity-multifunctionality relationships in many of the world's ecosystems.
Loreau, M. et al. Biodiversity and ecosystem functioning: Current knowledge and future challenges. Science 294, 804-808 (2001).
Hooper, D. U. et al. Effects of biodiversity on ecosystem functioning: A consensus of current knowledge. Ecol. Monogr. 75, 3-35 (2005).
Balvanera, P. et al. Quantifying the evidence for biodiversity effects on ecosystem functioning and services. Ecol. Lett. 9, 1146-1156 (2006).
Cardinale, B. J. et al. The functional role of producer diversity in ecosystems. Am. J. Bot. 98, 572-592 (2011).
Hooper, D. U. & Vitousek, P. M. Effects of plant composition and diversity on nutrient cycling. Ecol. Monogr. 68, 121-149 (1998).
Hector, A. & Bagchi, R. Biodiversity and ecosystem multifunctionality. Nature 448, 188-191 (2007).
Gamfeldt, L., Hillebrand, H. & Jonsson, P. R. Multiple functions increase the importance of biodiversity for overall ecosystem functioning. Ecology 89, 1223-1231 (2008).
Zavaleta, E. S., Pasari, J. R., Hulvey, K. B. & Tilman, G. D. Sustaining multiple ecosystem functions in grassland communities requires higher biodiversity. Proc. Natl Acad. Sci. USA 107, 1443-1446 (2010).
Isbell, F. et al. High plant diversity is needed to maintain ecosystem services. Nature 477, 199-203 (2011).
Maestre, F. T. et al. Plant species richness and ecosystem multifunctionality in global drylands. Science 335, 214-218 (2012).
Gamfeldt, L. et al. Higher levels of multiple services are found in forests with more tree species. Nat. Commun. 4, 1340 (2013).
Byrnes, J. E. K. et al. Investigating the relationship between biodiversity and ecosystem multifunctionality: Challenges and solutions. Methods Ecol. Evol. 5, 111-124 (2014).
Bradford, M. A. et al. Discontinuity in the responses of ecosystem processes and multifunctionality to altered soil community composition. Proc. Natl Acad. Sci. USA 111, 14478-14483 (2014).
Perkins, D. W. et al. Higher biodiversity is required to sustain multiple ecosystem processes across temperature regimes. Glob. Chang. Biol. 21, 396-406 (2015).
Lefcheck, J. S. et al. Biodiversity enhances multifunctionality across trophic levels and habitats. Nat. Commun. 6, 6936 (2015).
Huston, M. A. Hidden treatments in ecological experiments: Re-evaluating the ecosystem function of biodiversity. Oecologia 110, 449-460 (1997).
Tilman, D., Lehman, C. L. & Thomson, K. T. Plant diversity and ecosystem productivity: Theoretical considerations. Proc. Natl Acad. Sci. USA 94, 1857-1861 (1997).
Loreau, M. & Hector, A. Partitioning selection and complementarity in biodiversity experiments. Nature 412, 72-76 (2001).
Garnier, E. et al. Plant functional markers capture ecosystem properties during secondary succession. Ecology 85, 2630-2637 (2004).
Winfree, R., Fox, J. W., Williams, N. M., Reilly, J. R. & Cariveau, D. P. Abundance of common species, not species richness, drives delivery of a real-world ecosystem service. Ecol. Lett. 18, 626-635 (2015).
Lee, C. F. Financial Analysis and Planning: Theory and Application (Addison-Wesley, Reading, Mass, 1985).
Doak, D. F. et al. The statistical inevitability of stability-diversity relationships in community ecology. Am. Nat. 151, 264-276 (1998).
Tilman, D. et al. Diversity-stability relationships: Statistical inevitability or ecological consequence? Am. Nat. 151, 277-282 (1998).
Aerts, R. & Honnay, O. Forest restoration, biodiversity and ecosystem functioning. BMC Ecol. 11, 19 (2011).
Scherer-Lorenzen, M. in Forests and Global Change. (eds Burslem, D., Coomes, D. & Simonson, W.) 195-238 (Cambridge Univ. Press, 2014).
Baeten, L. et al. A novel comparative research platform designed to determine the functional significance of tree species diversity in European forests. Perspect. Plant Ecol. Evol. Syst. 15, 281-291 (2013).
Jucker, T., Bouriaud, O., Avacaritei, D. & Coomes, D. A. Stabilizing effects of diversity on aboveground wood production in forest ecosystems: Linking patterns and processes. Ecol. Lett. 17, 1560-1569 (2014).
Loreau, M. Biodiversity and ecosystem functioning: A mechanistic model. Proc. Natl Acad. Sci. USA 95, 5632-5636 (1998).
Reich, P. B. The world-wide 'fast-slow' plant economics spectrum: A traits manifesto. J. Ecol. 102, 275-301 (2014).
Manning, P., Morriston, S. A., Bonkowski, M. & Bardgett, R. D. Nitrogen enrichment modifies plant community structure via changes to plant-soil feedback. Oecologia 157, 661-673 (2008).
Grossiord, C. et al. Tree diversity does not always improve resistance of forest ecosystems to drought. Proc. Natl Acad. Sci. USA 111, 14812-14815 (2014).
Ampoorter, E. et al. Do diverse overstoreys induce diverse understoreys?: Lessons learnt from an experimental-observational platform in Finland. Forest Ecol. Manag. 318, 206-215 (2014).
Zhang, Y., Chen, H. Y. H. & Reich, P. B. Forest productivity increases with evenness, species richness and trait variation: A global meta-analysis. J. Ecol. 100, 742-749 (2012).
Clark, D. A. & Clark, D. B. Life history diversity of canopy and emergent trees in a neotropical rain forest. Ecol. Monogr. 62, 315-344 (1992).
Bachmann, P. Wirtschaftliche Ü berlegungen zur Waldpflege. HESPA Mitt. 1, 1-24 (1970).
Jucker, T. et al. Competition for light and water play contrasting roles in driving diversity-productivity relationships in Iberian forests. J. Ecol. 5, 1202-1213 (2014).
Tamminen, P. & Starr, M. Bulk density of forested mineral soils. Silva Fennica 28, 53-60 (1994).
Viro, P. J. Kivisyyden maärittämisestä. Summary: On the determination of stoniness. Comm. Inst. For. Fenn. 40, 23 (1952).
Vance, E. D., Brookes, P. C. & Jenkinson, D. S. An extraction method for measuring soil microbial biomass C. Soil Biol. Biochem. 19, 703-707 (1987).
Joergensen, R. G. The fumigation-extraction method to estimate soil microbial biomass: Calibration of the kEC value. Soil Biol. Biochem. 28, 25-31 (1996).
Skjemstad, J. O. & Baldock, J. A. in Soil Sampling and Methods of Analysis 2nd edn (eds Carter, M.R. & Gregorich, E.G.), 225-238 (CRC Press, 2007).
Matejovic, I. Determination of carbon, hydrogen, and nitrogen in soils by automated elemental analysis (dry combustion method). Commun. Soil Sci. Plant Anal. 24, 2213-2222 (1993).
Vesterdal, L., Schmidt, I. K., Callesen, I., Nilsson, L. O. & Gundersen, P. Carbon and nitrogen in forest floor and mineral soil under six common European tree species. For. Ecol. Manage. 255, 35-48 (2008).
Offerman, C. et al. The long way down - Are carbon and oxygen isotope signals in the tree ring uncoupled from canopy physiological processes? Tree Physiol. 31, 1088-1102 (2011).
Eichhorn, J. et al. in UNECE (Ed.) Manual on Methods and Criteria for Harmonized Sampling, Assessment, Monitoring and Analysis of the Effects of Air Pollution on Forests 49 (UNECE, ICP Forests Programme Co-ordinating Centre, 2010).
Spehn, E. M. et al. Ecosystem effects of biodiversity manipulations in European grasslands. Ecol. Monogr. 75, 37-63 (2005).
Loreau, M. & De Mazancourt, C. Species synchrony and its drivers: Neutral and nonneutral community dynamics in fluctuating environments. Am. Nat. 172, E48-E66 (2008).
