Impact of land-use and functional diversity on diversity and stability of grassland communities in fragmented landscapes
Final Report Abstract
We developed a computer simulation model to better understand how grassland plants might respond to land-use intensity (for example, how often a field is mowed or grazed) in the context of habitat fragmentation (for example, how easy it is for a plant’s seeds to reach another grassland). The computer simulation model allowed us to evaluate different scenarios and different possible initial conditions, and to ask “what-if” questions. This approach enables testing the plausibility of hypotheses derived from empirical work and can provide new insights and hypotheses to test in the field. We created a flowchart that identifies some potential pitfalls in studying trait diversity, where trait diversity is unlikely to contribute to long-term ecosystem functioning. To develop our simulation model, we expanded an existing single species model to be able to examine ways in which species might interact. For example, if one species is already well established, there may not be room for a second species to grow. In contrast, if another species is more adversely affected by land use, such as mowing or grazing, this may provide an opportunity for the second species to increase in abundance and biomass. These dynamics are more difficult to model in a single species model. Further, we modified the model to incorporate changes in the environment, as these can have a large impact on species dynamics as well. We published our model in the scientific literature, including detailed documentation on how to use it. The model is free, open source, and was implemented in the software R, and can be used for examining simple metacommunity dynamics for plants and other stationary organisms. We set out to incorporate trait diversity into our analysis, but found many definitions of trait diversity, many of which were unsuitable for our project. Consequently, we validated an under-used approach to trait diversity, and published an R package with code to calculate our new measure on the Comprehensive R Archive Network (CRAN). Finally, we began the process of parameterizing the model based on the 150 grassland sites in Germany (the Biodiversity Exploratories).
Publications
- 2016. SpatialDemography: a new, spatially explicit, stage-structured, metacommunity model for studying plant demography. Ecography 39: 1129-1137
Keyel, A.C., J.L.K. Gerstenlauer, and K. Wiegand
(See online at https://doi.org/10.1111/ecog.02295) - 2016. Validating the use of Unique Trait Combinations for measuring multivariate functional richness. Methods in Ecology and Evolution 7: 929- 936
Keyel, A.C. and K. Wiegand
(See online at https://doi.org/10.1111/2041-210X.12558) - Land-use intensification causes multitrophic homogenization of grassland communities. Nature 540: 266-269
Gossner, M.M., Lewinsohn, T.M., Kahl, T., Grassein, F., Boch, S. Prati, F. Birkhofer, K., Renner, S.C., Sikorski, J., Wubet, T., Arndt, H., Baumgartner, V., Blaser, S., Blüthgen, N., Börschig, C., Buscot, F., Diekötter, T., Ré Jorge, L., Jung, K, Keyel, A.C., Klein, A- M., Klemmer, S., Krauss, J., Lange, M., Müller, J., Overmann, J., Pašalić, E., Penone, C., Perović, D.J., Purschke, O, Schall, P., Socher, S.A., Sonnemann, I., Tschapka, M., Tscharntke, T., Türke, M., Venter, P.C., Weiner, C.N., Werner, M., Wolters, V., Wurst, S. Westphal, C., Fischer, M., Weisser, W.W., and Allen, E.
(See online at https://doi.org/10.1038/nature20575)
