The relative effects of abiotic and biotic parameters on plant species performance and their inclusion in species distribution models
Zusammenfassung der Projektergebnisse
Species have responded to past global changes by shifting their ranges. Ecologists use species distribution models to predict these range shifts. In the process of constructing these models it is assumed that species distributions can be explained by abiotic (climatic and edaphic) factors alone, ignoring the role of biotic processes. Current practice therefore ignores an important suite of factors that potentially influence species performance and distribution. It could, therefore, be argued that forecasts of future species ranges and associated assessments of future biodiversity distributions are fundamentally flawed. The aim of this project was to investigate the relative effect of both abiotic and biotic factors on the performance and distribution of plant species and to contribute to the improvement of widely used species distribution models. In an empirical framework we investigated the relative effect of both abiotic and biotic factors on the performance (as described by 16 selected plant functional traits, among others specific leaf area, canopy height, aboveground biomass, leaf nutrient and stable isotope concentration) of five selected species (Campanula glomerata, Centaurea jacea, Plantago media, Salvia pratensis and Trifolium montanum) in 41 dry grassland sites being widely distributed in Europe. The results showed that target species performances were clearly influenced by both, biotic and abiotic factors, and that these effects were clearly species specific. Especially species richness of the surrounding vegetation had a significant impact on most of the investigated plant traits, for example on stomata density and specific leaf area. Most important abiotic factors were the climate parameter annual precipitation as well as soil nitrogen content. Accordingly, species rankings of the traits were not consistent across the large geographical gradient, leading to a violation of the species robustness assumption. These results have important consequences for species distribution models as they show that species performances and hence species distributions are strongly determined by a blend of abiotic and biotic factors. In a theoretical framework we examined the current state of the art in species distribution modelling and explored avenues for including more biological mechanisms into such models. We defined a comprehensive agenda for including competitive processes and biotic interactions in species distribution models. In particular, we used a well-established theory of community interactions to develop a method for inferring how biotic and abiotic processes interact to determine distribution patterns. We tested the method using simulated distribution data and showed that the model can retrieve the parameters that generated the data. We concluded that the method is robust enough to be used on real datasets. The project revealed that it is necessary to include more biology into species distribution models also on large spatial scales to adequately predict shifts in biodiversity in a changing world. The developed agenda for modelling species distributions will deepen our understanding of underlying processes determining actual species distribution patterns. Further studies should focus on an implementation of this agenda to predict species distributions from biotic and abiotic factors also for a wider set of species and in different habitats or biomes in the world.
Projektbezogene Publikationen (Auswahl)
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(2009) Be aware of your neighbours! Niche modelling including a competition factor. Niche Evolution - a unifying concept for systematic, ecology, paleontology and conservation biology. 3-4 July 2009, Zurich, Switzerland
Römermann, C., Golinko, A., Grün, C. & Higgins, S. I.
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(2009) Is the state of equilibrium assumption justified in niche modelling? Annual meeting of Ecological Society of Germany, Switzerland and Austria (GfÖ) 2009, Bayreuth
Golinko A., Higgins S., Grün C. & Römermann, C.
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(2009) Using local scale information to qualify the influence of abiotic and biotic factors on plant species performance and distribution. Annual meeting of Ecological Society of Germany, Switzerland and Austria (GfÖ) 2009, Bayreuth
Grün C., Römermann, C., Golinko A. & Higgins S.
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(2012) A niche for biology in species distribution models. Journal of Biogeography, 39, 2091-2095
Higgins, S.I., O'Hara, R.B. & Römermann, C.
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(2012) Novel approaches to modelling biotic interactions in multispecies assemblages at broad spatial scales. Journal of Biogeography, 39, 2163–2178
Kissling, W.D., Dormann, C.F., Groeneveld, J., Hickler, T., Kühn, I., McInerny, G., Montoya, J.M., Römermann, C., Schiffers, K., Schurr, F., Singer, A., Svenning, J.C., Zimmermann, N.E. & R.B. O’Hara
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(2012) Special Issue: The ecological niche as a window to biodiversity. Journal of Biogeography 39: 2089
Higgins SI, Römermann C, O'Hara RB
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(2012) The correlative-process continuum of distribution models. Journal of Biogeography, 39, 2119–2131
Dormann, C.F., Schymanski, S.J., Cabral, J., Chuine, I., Graham, C., Hartig, F., Kearney, M., Morin, X., Römermann, C., Schröder, B. & Singer, A.
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(2013) Factors driving plant rarity in dry grasslands on different spatial scales: a functional trait approach. Biodiversity and Conservation, 22, 2337-2353
Lauterbach, D., Römermann, C., Jeltsch, F. & Ristow, M.
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(2013) Intraspecific trait variability across different axes and implications for vegetation database analyses. 12th meeting on vegetation databases: “Linking vegetation and plant trait databases”, Leipzig March 2013
Römermann
