Exploring the relationship between diversity and productivity of a semi-natural permanent grassland using plant functional traits

摘要

Recent studies have indicated that plant functional traits are important instruments for analysing functional diversity of grasslands. We present the results of a study on the relationship between diversity and productivity conducted in the Soiling Uplands, Germany. The experimental site is an old permanent semi-natural grassland, with no history of arable farming. The three-factorial Latin square design with six blocked replications includes sward type (control, monocot-reduced and dicot-reduced byherbicide application), mowing frequency (1 and 3 cuts per year) and fertilization intensity (no fertilization and 180-30-100 kg ha~(-1) of N-P-K) as main factors, and block and row effects as spatial factors. On each plot, we collected information on six plant functional traits for the main species making up 80% of the yield: plant height, green leaves/total leaves ratio, leaf dry matter content, stem dry matter content, stem specific density, and specific leaf area. We found that the functional diversity index (FD), defined as the total branch length of a functional dendrogram based on a species-traits matrix, increases with higher cutting frequency and decreases with higher fertilizer input. The main factor influencing the differences in the functional diversity index is the number of species making up 80% of the yield.