CHANGES IN THE SPECIES DIVERSITY OF GRASSLAND COMMUNITIES DURING SECONDARY SUCCESSION
A. Nawrath, F. Hrabe, P. Knot, M. Kvasnovsky, P. Slama, J. Skladanka
Abstract: Treatments of N, P and K fertilization levels were studied over the course of 18 years (1992–2009) of secondary succession in a semi-cultural permanent meadow community of Sanquisorba Festucetum comutatae on a mesophytic site in a fodder
production area. Results of the evaluation of species diversity levels show that on average only 23.7 species (max. 34 species) contribute to actual fodder production, i.e. only 44% of species ascertained. A high level of N fertilization – 180 kg.ha–1 year–1 – significantly lowered the number of species (average – 19.9) in comparison to the variant without NPK (25.3 species), as well as in comparison to PK (26.3) and 90 kg N–1 year–1 + PK (23.4). Grasses make up on average 43.0% of the total number of species, legumes 5.9% and other herbs 51.1%. In the course of secondary succession, the number of species averaged across all treatments significantly increased, with 25.6 species in the 3rd post-stabilization phase (years 13–18) and 20.8 species in the 1st phase of succession (years 1–6). From % dominance point of view (expressed as the percentage weight of different species groups relative to total weight), there was a significant decrease in % dominance of grass components from 60.8% (1st phase) to 47.8% (3rd phase) and an increase in % dominance of other herbs from 35.3% (1st phase) to 46.8% (3rd phase). Across all successional phases, intensive N + PK fertilization significantly increased % dominance of grass components from 41.1%, and 39.8% for the variants without N fertilization, to 59.2% for N 90 and 69.7% for N 180 kg.ha–1 year–1 variant.
production area. Results of the evaluation of species diversity levels show that on average only 23.7 species (max. 34 species) contribute to actual fodder production, i.e. only 44% of species ascertained. A high level of N fertilization – 180 kg.ha–1 year–1 – significantly lowered the number of species (average – 19.9) in comparison to the variant without NPK (25.3 species), as well as in comparison to PK (26.3) and 90 kg N–1 year–1 + PK (23.4). Grasses make up on average 43.0% of the total number of species, legumes 5.9% and other herbs 51.1%. In the course of secondary succession, the number of species averaged across all treatments significantly increased, with 25.6 species in the 3rd post-stabilization phase (years 13–18) and 20.8 species in the 1st phase of succession (years 1–6). From % dominance point of view (expressed as the percentage weight of different species groups relative to total weight), there was a significant decrease in % dominance of grass components from 60.8% (1st phase) to 47.8% (3rd phase) and an increase in % dominance of other herbs from 35.3% (1st phase) to 46.8% (3rd phase). Across all successional phases, intensive N + PK fertilization significantly increased % dominance of grass components from 41.1%, and 39.8% for the variants without N fertilization, to 59.2% for N 90 and 69.7% for N 180 kg.ha–1 year–1 variant.
Keywords: dominance; fertilization; grasses; herbs; legumes; permanent meadow
Date published: 2017-09-18
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