Back to the roots: how do seedlings of native tree species react to the competition by exotic species?
- 296 Downloads
Identifying the traits of exotic species may explain their invasiveness and help control the negative impacts of these species on native ecosystems. In this study, we investigated root competition as an important driver for the competitiveness of two exotic tree species in the seedling stage.
In a pot experiment, carried out in Central Europe, we studied the effect of root competition of two exotic tree species (Prunus serotina Ehrh. and Robinia pseudoacacia L.) on biomass allocation of two native ones (Quercus robur L. and Carpinus betulus L.).
Seedlings of these species were exposed to intra- and interspecific mixtures with and without the effect of root competition. For this, belowground plastic partitions were installed in the pots.
Competition intensity in the pots increased over time, irrespective of mixture type. However, this increase was much higher for the native species if mixed with the exotic species compared to monocultures or inter-native mixtures. In addition to ontogeny, competition affected biomass allocation patterns. Under root competition by the exotic species, the native species preferentially allocated their biomass to the roots. A higher allocation to the roots was mainly achieved at the expense of leaf and branch biomass.
Root competition of P. serotina and R. pseudoacacia may be a reason for the lack of Q. robur and C. betulus in the seedling stage in natural environments where all four species occur.
KeywordsBiomass allocation Balanced growth hypothesis Pot experiment Prunus serotina Robinia pseudoacacia
We are grateful to K.-H. Heine, A. Parth, M. Unger, T. Waldmann, and U. Westphal and to all other helpers who were a big support while collecting the data.
We would like to thank the Marianne and Dr. Fritz-Walter Fischer Foundation within the Stifterverband für die Deutsche Wissenschaft for funding our research and the DAAD (German Academic Exchange Service) VIGONI program for supporting project-based exchange.
- Bourtsoukidis E, Kawaletz H, Radacki D, Schütz S, Hakola H, Hellén H, Noe S, Mölder I, Ammer C, Bonn B (2013) Impact of flooding and drought conditions on the emission of volatile organic compounds of Quercus robur and Prunus serotina. Trees. doi: https://doi.org/10.1007/s00468-013-0942-5 CrossRefGoogle Scholar
- DAISIE Project (2009) Handbook of alien species in Europe. Springer, New York, 399 ppGoogle Scholar
- Ellenberg H (1988) Vegetation ecology of Central Europe, 4th edn. Cambridge University Press, CambridgeGoogle Scholar
- Goldberg DE (1990) Components of resource competition in plant communities. In: Grace JB, Tilman D (eds) Perspectives on plant competition. Academic, San Diego, pp 27–49Google Scholar
- Haase JU (2009) Biodiversity and ecosystem functioning: the effects of tree and litter diversity. Dissertation, University of ZurichGoogle Scholar
- Hofmann R, Ammer C (2008) Biomass partitioning of beech seedlings under the canopy of spruce. Austrian J For Sci 125:51–66Google Scholar
- Horn HS (1971) The adaptive geometry of trees. Princeton University Press, PrincetonGoogle Scholar
- Oliver CD, Larson BC (1990) Forest stand dynamics. McGraw-Hill, New YorkGoogle Scholar
- R Development Core Team (2012) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, AustriaGoogle Scholar
- Wetterstation Göttingen (2013) http://www.wetterstation-goettingen.de/. Accessed 29 January 2013