Speaker
Description
In plant communities, species often don´t arrive simultaneously at a new site. The effect of an early-arriving species (EAS) on the establishment, growth and reproduction of a late-arriving species (LAS) is referred to as priority effect. Despite increasing evidence that priority effects play an important role in community assembly processes (Ejrnæs, Bruun and Graae, 2006; Körner et al., 2008), the underlying mechanisms are not fully understood (Fukami, 2015).
To achieve a deeper understanding of the mechanisms underlying the priority effects of native and exotic plant species, we conducted a multi-species field experiment, with LAS arriving two years later than EAS. To gain better insights into the role of direct competition and soil fungi accumulation in this process, we implemented two treatments: a fungicide treatment (for the removal of the soil fungi accumulated by EA plants) and an herbicide treatment (for the removal of EA plants and in consequence their direct competitive effects).
Consistent with our expectation, we found that the strength of the direct competition effect depended on the biomass of the EAS. Additionally, both the priority effect mediated by soil fungi and that mediated by direct competition were influenced by the origin of the EAS and LAS. Furthermore, we demonstrated that the soil fungi accumulated by the EAS had not only a direct effect on the LAS but also an indirect effect through their influence on the performance of the EAS, thereby affecting the strength of the competition effect.
Our results support the assumption that both direct competition and soil-borne pathogenic fungi are important drivers of priority effects, and that both depend on the origin of the interacting species. These results do not only contribute to our mechanistic understanding of assembly processes but are also relevant for the management of invasive species and habitat restoration.
| Status Group | Doctoral Researcher |
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