Variation of seedling recruitment in wet meadow species over 6 years: Positive effects of mowing and negative effects of fertilization

Abstract Germination and seedling recruitment are stages of the plant life cycle, which are highly sensitive to biotic and abiotic filtering. Simultaneously, seedling regeneration is considered crucial for biodiversity maintenance in grasslands and is strongly affected by grassland management. The response of seedling regeneration to management and its interannual variability remain understudied. We studied the effects of mowing, fertilization, dominant removal and their combinations on the seedling composition in a species‐rich wet meadow community in Central Europe. We also measured litter and moss cover and analysed their effect on seedlings. First, we analysed the total seedling numbers and species composition across six consecutive years. Second, we tested the spatial relationship between conspecific seedling–adult pairs and its strength by comparing it against that of heterospecific seedling–adult pairs and explained the observed pattern with species traits, namely the dispersal mode. Total seedling numbers were significantly decreased by fertilization, and significantly increased by mowing. Increased litter cover was an important mechanism causing the extremely low numbers of seedlings in fertilized plots. The association between conspecific seedling–adult pairs was always significantly positive and higher than for heterospecifics. The tightness of the relationship was determined by individual species' dispersal mode. We found that a key process of the plant species life cycle, seedling regeneration, was overwhelmingly negatively affected by fertilization in experimental plots. Mowing is efficient in preserving species' successful regeneration, but only in unfertilized plots. Large differences in both total seedling numbers and species proportions between individual years suggested that different species probably establish themselves in different years, which is a co‐existence maintaining mechanism suggested by Grubb's regeneration niche theory. Such high spatio‐temporal variability in seedling recruitment forms the basis for niche partitioning and storage effects as mechanisms of biodiversity maintenance in wet meadow communities. Read the free Plain Language Summary for this article on the Journal blog.