University of Oulu

Jessen, M.-T., Auge, H., Harpole, W. S., & Eskelinen, A. (2023). Litter accumulation, not light limitation, drives early plant recruitment. Journal of Ecology, 111, 1174–1187.

Litter accumulation, not light limitation, drives early plant recruitment

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Author: Jessen, Maria-Theresa1,2,3; Auge, Harald1,2; Harpole, W. Stanley1,3,4;
Organizations: 1German Centre for Integrative Biodiversity Research-iDiv Halle-Jena-Leipzig, Leipzig, Germany
2Department of Community Ecology, Helmholtz Centre for Environmental Research-UFZ, Halle, Germany
3Department of Physiological Diversity, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
4Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
5Department of Ecology and Genetics, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.3 MB)
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Language: English
Published: John Wiley & Sons, 2023
Publish Date: 2023-08-15


1. Theory predicts a decline in grassland diversity under nutrient enrichment and loss of herbivory, and one possible cause is hampered seedling recruitment. Two potential drivers for reduced diversity at the seedling level are diminished light availability caused by surrounding vegetation and accumulation of dead biomass.

2. To test the importance of these two mechanisms on early recruitment, we added seeds of 15 herbaceous grassland plant species and monitored sown and natural seedling emergence during one growing season in a full factorial field experiment with light addition and litter removal under fertilization and exclusion of mammalian herbivores in an experimental grassland in Central Germany. We used modern LED lamps, mimicking the spectrum of natural sun light, to provide light to small-statured understorey plants. This novel experimental set-up allowed us to specifically disentangle the roles of light limitation and litter accumulation independently and in combination.

3. In general, herbivore exclusion, but not fertilization increased the amount of litter biomass. Litter removal increased seedling number and richness by 83% and 33%, respectively, while light addition had no significant main effect on seedling recruitment, nor did it interact with any other factors, and did not affect recruitment even when litter was removed. In addition, fertilization had a negative and herbivore exclusion a negligible impact on recruitment, and these effects were independent of litter removal. Furthermore, seedling number and richness were unrelated to light intensity and quality, litter depth, soil moisture, temperature and C:N ratio.

4. Synthesis: These results provide novel insights into the role of light limitation versus litter accumulation driving early recruitment and help understanding the mechanisms that affect diversity in grassland communities via recruitment. Our results highlight the detrimental role of litter accumulation as opposed to surrounding vegetation induced light deficiency driving early recruitment from seeds and call for management actions that reduce the amount of litter when maintaining or restoring diversity.

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Series: Journal of ecology
ISSN: 0022-0477
ISSN-E: 1365-2745
ISSN-L: 0022-0477
Volume: 111
Issue: 6
Pages: 1174 - 1187
DOI: 10.1111/1365-2745.14099
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: This study was funded by the iDiv Flexpool Program (grant no. 34600565-11) and a Finnish Academy Research grant (project 29719) to A.E. We appreciate the Helmholtz Association, the Federal Ministry of Education and Research, the State Ministry of Science and Economy of Saxony-Anhalt and the State Ministry for Higher Education, Research and the Arts Saxony to fund the Global Change Experimental Facility (GCEF) project.
Dataset Reference: All data associated with this study are publicly available at Figshare (Jessen et al., 2023).
Copyright information: © 2023 The Authors. Journal of Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.