Effects of disturbance and seed addition on plant community assembly and ecosystem functions

Picture: The photo shows, photographed from above, two young female scientists on the right and left of the picture, lying on a sunlit meadow and busy with the determination of seedlings. The female scientist on the right is noting something on paper in a clipboard lying on the ground in front of her. In front of the head of the female scientist on the left, a thin marking stick is stuck in the ground, next to her lies an unfolded folding ruler.

Background

Experiments controlling plant diversity have often demonstrated positive relations between the number of plant species and ecosystems functions such as productivity, stability and resistance against perturbations and invasions. Yet, there is an ongoing debate how these findings from rather artificial and strongly controlled experiments scale up to real-world ecosystems and how this can be practically implemented. In our project, we will specifically address the effects of land-use intensity and (experimentally enriched) plant diversity on seed rain and a number of specific ecosystem functions such as productivity, litter decomposition, root exudation, and nitrogen cycling.

Hypotheses

In the disturbance and seed addition experiment SADE we will specifically ask the question how sward disturbance and assisted migration by sowing affect community reassembly and essential ecosystem functions along a real-world gradient of land-use intensities in grasslands. This will also allow testing higher plant diversity to enable higher levels of ecosystem services. Specifically we will address the following hypotheses:

The species richness of the seed rain has strong influence on the plant species richness of the disturbed vegetation.
The floristic enrichment will also lead to a higher diversity of the seed rain.
Subordinate and transient species, which emerged after sward disturbance from the seed bank, will play a crucial role for the maintenance of ecosystem functioning no longer than two years after the disturbance event.
Just in species-poor grasslands, plant diversity will increase after sward disturbance even without seed addition due to species emerging from the seed bank.
Species enrichment by seed addition will enhance ecosystem functions such as biomass production, fodder quality, drought resistance and litter decomposition in previously species-poor grasslands.
Higher levels of plant diversity will also positively affect root exudation and nutrient retention due to reduced losses of nutrients to deeper soil layers.

Methods

Our project will analyse all 73 plots in the three study regions where the SADE experiment is implemented. Together with the Botany project, we will monitor the development of the vegetation in each year. To record seed rain aluminium trays, which are filled with sterile soil, will be temporarily installed catching seeds, which are falling from the vegetation to the ground. As major response variables for plant-related ecosystem functioning we will analyse aboveground productivity and nutrient stocks in biomass, including nitrogen and carbon isotopic signals as proxies for nitrogen uptake and drought resistance. Furthermore, we will measure decomposition rates of different kinds of plant litter and assess nutrient availability using resin bags. By applying the standardised tea bag method within the litter decomposition study by using green tea and roisbos tea, we are also part of the worldwide project TeaComposition.

Picture: The photo shows a green meadow with three yellow square frames delimiting sampling areas. Across the image is a yellow band delimiting a plot. At the top left of the image is a thin marking stick stuck in the ground.

By sampling the above-ground plant biomass on a defined area, the productivity and later in the laboratory also the feed value and isotope are determined

Picture: The photo shows a pile of dug-up earth in a meadow, on which a metal hand shovel is lying, on top of which is a cloth bag filled with exchange resins

Resin bags are cloth bags filled with exchange resins, which are temporarily placed in the soil to measure the availability of nutrients in the soil

The determination of seedlings requires expertise as well as patience and good eyesight

Picture: The photo shows a table in a room with an orange-brown top with a wood grain. A turquoise hand shovel lies on the table. Three tea bags filled with tea lie on the shovel and on the table top in front of it.

Normal tea bags are used to compare the effectiveness of the site in litter decomposition and to compare different ecosystems with each other

Publications

Increasing plant species richness by seeding has marginal effects on ecosystem functioning in agricultural grasslands

Freitag M., Hölzel N., Neuenkamp L., van der Plas F., Manning P., Abrahão A., Bergmann J., Boeddinghaus R., Bolliger R., Hamer U., Kandeler E., Kleinebecker T., Knorr K.-H., Marhan S., Neyret M., Prati D., Le Provost G., Saiz H., van Kleunen M., Schäfer M., Klaus V. H. (2023): Increasing plant species richness by seeding has marginal effects on ecosystem functioning in agricultural grasslands. Journal of Ecology 111 (9), 1968-1984. doi: 10.1111/1365-2745.14154

Enzyme kinetics inform about mechanistic changes in tea litter decomposition across gradients in land-use intensity in Central German grasslands

Teebeutel und Enzymkinetik als Indikatoren für Auswirkungen der Landnutzungsintensität auf die Streuzersetzung in Grünland in Mitteldeutschland.

Meyer U.-N., Tischer A., Freitag M., Klaus V. H., Kleinebecker T., Oelmann Y., Kandeler E., Hölzel N., Hamer U. (2022): Enzyme kinetics inform about mechanistic changes in tea litter decomposition across gradients in land-use intensity in Central German grasslands. Science of The Total Environment 836, 155748. doi: 10.1016/j.scitotenv.2022.155748

The influence of seeding and disturbance on beta diversityof grassland vegetation of different land use intensities

Holthuis P. M. (2022): The influence of seeding and disturbance on beta diversityof grassland vegetation of different land use intensities. Master thesis, University Münster

Restoration of plant diversity in permanent grassland by seeding: Assessing the limiting factors along land-use gradients

Freitag M., Klaus V. H., Bolliger R., Hamer U., Kleinebecker T., Prati D., Schäfer D., Hölzel N. (2021): Restoration of plant diversity in permanent grassland by seeding: Assessing the limiting factors along land-use gradients. Journal of Applied Ecology 58 (8), 1681-1692. doi: 10.1111/1365-2664.13883

Land-use intensity shapes the composition of seed rain in permanent grasslands

Kunze S. (2021): Land-use intensity shapes the composition of seed rain in permanent grasslands. Master thesis, University Münster

Linking land use and plant community assembly to understand ecosystem processes in temperate grasslands

Freitag M. (2021): Linking land use and plant community assembly to understand ecosystem processes in temperate grasslands. Dissertation, University of Münster

Dark diversity as a tool to predict the establishment success of plant species in grassland restoration

Närmann, S. (2021): Dark diversity as a tool to predict the establishment success of plant species in grassland restoration. Master Thesis, University of Münster, Münster.

Auswirkungen von Störung auf den Trockenheitsstress in der Vegetation und die Stickstoff-Ausnutzung der Pflanzen

Schröder S. K. (2021): Auswirkungen von Störung auf den Trockenheitsstress in der Vegetation und die Stickstoff-Ausnutzung der Pflanzen. Technical report, University Münster

Does disturbance and seed addition affect plant functional diversity in grasslands along a land-use gradient?

Beeinflussen Ansaat und Störung die pflanzliche funktionelle Diversität des Wirtschaftsgrünlandes entlang eines Landnutzungsgradienten?

Binder J. H. (2019): Does disturbance and seed addition affect plant functional diversity in grasslands along a land-use gradient? Bachelor Thesis, University Münster

Der Einfluss von Störung und Ansaat auf die Bodenphosphorkonzentration im Wirtschaftsgrünland

Hiestermann S. (2019): Der Einfluss von Störung und Ansaat auf die Bodenphosphorkonzentration im Wirtschaftsgrünland. Bachelor Thesis, University Münster

Einfluss von Ansaat und Störung auf die Kohlenstoff- und Stickstoffverfügbarkeit in Grünlandböden der Region Hainich-Dün

Schaper J. (2019): Einfluss von Ansaat und Störung auf die Kohlenstoff- und Stickstoffverfügbarkeit in Grünlandböden der Region Hainich-Dün. Bachelor Thesis, University Münster

Etablierung von Grünlandarten durch Störung und Ansaat im Wirtschaftsgrünland

Närmann S. (2018): Etablierung von Grünlandarten durch Störung und Ansaat im Wirtschaftsgrünland. Bachelor thesis, Münster University

Samenregen im temperaten Grünland

Partsch V. (2018): Grazing and its ecological effects: A new index for grazing intensity in grasslands. Bachelor thesis, University Muenster

Einfluss von Pflanzendiversität und Landnutzungsintensität auf Biomasseproduktion und Futterqualität im Grünland in Hainich-Dün

Thurner L. (2018): Einfluss von Pflanzendiversität und Landnutzungsintensität auf Biomasseproduktion und Futterqualität im Grünland in Hainich-Dün. Bachelor Thesis, University Muenster.

Resistenz und Resilienz von Pflanzengemeinschaften des Wirtschaftsgrünlandes gegenüber Ansaat und Störung

Stroot L. (2018): Resistenz und Resilienz von Pflanzengemeinschaften des Wirtschaftsgrünlandes gegenüber Ansaat und Störung. Bachelor Thesis, University Muenster.

Eine Langzeitanalyse der Beziehungen zwischen Landnutzungsintensität, Aufwuchsqualität und Pflanzendiversität im Grünland

Froese L. (2017): Eine Langzeitanalyse der Beziehungen zwischen Landnutzungsintensität, Aufwuchsqualität und Pflanzendiversität im Grünland. Bachelor thesis, University Münster