Meta RUE

The aim of the project is to elucidate how major ecosystem functions such as primary production, as well as corresponding ecological indicators such as the rain-use efficiency, in (semi-)arid ecosystems are influenced by the environmental factor-layers climate, soil and management (i.e. land use).
Dryland ecosystems are characterized by a high climatic variability, especially in precipitation. Since precipitation can be considered as the main limiting factor for primary production in (semi-)arid regions, this high variability translates into strong intra- and interannual variability of primary production. However, in many regions this close relationship is strongly modulated by human management and landuse practices: (semi-)arid regions are often overused by means of resource outtake and disturbance regime. This can lead to an overdrive of the relationship between climate and primary production and thus may lead to degradation processes and even system shifts. At the same time primary production in drylands is the main source of forage for domestic livestock production and therefore one of the most important sources of livelihood security for a large proportion of people in these areas. The high variability in primary production thus threatens millions of people who depend on a reliable provision of primary production as forage for their domestic animals.
The central methodology of this project is a quantitative meta-analysis on primary production (i.e. ANPP) and the relationship between precipitation and ANPP (rain-use efficiency), as well as abiotic and biotic drivers. Earlier findings have shown that both ANPP and rain-use efficiency are influenced by a wide set of variables (Ruppert et al. submitted). The tool of quantitative meta-analysis enables the separation of these effects into discriminable, quantitative effect sizes.
The meta-analysis focuses on long-term datasets which allows the assessment of temporal variability at a given site. The project benefits from a large body of published data on primary production in dryland systems worldwide. Datasets from experimental and monitoring sites are merged into a meta-database and analyzed by both canonical and modern statistical tools.
Main aim of the project is to contribute to a better functional understanding of vegetation dynamics in earth’s drylands. Results will also be used for recommended land-use practices and will be incorporated in dynamic vegetation models at the Crop Science Group, INRES University Bonn.

Ruppert, J.C., A. Linstädter, 2014. Convergence between ANPP estimation methods in grasslands - a practical solution to the comparability dilemma. Ecological Indicators 36, 524-531. DOI:10.1016/j.ecolind.2013.09.008.

Ruppert, J.C., A. Linstädter, 2013. Savanna or Grassland - Which biome is more resilient to anomalies in precipitation? A data fusion study in arid and semi-arid Africa. Proceedings of the Conference of the Ecological Society of Germany, Austria and Switzerland (GfÖ), September 9-13, Potsdam, Germany, 332-333. => link to conference abstract

Ruppert, J.C., A. Holm, S. Miehe, E. Muldavin, H.A. Snyman, K. Wesche, A. Linstädter, 2012. Meta-analysis of rain-use efficiency confirms indicative value for degradation and supports non-linear response along precipitation gradients in drylands. Journal of Vegetation Science 23, 1035-1050. DOI:10.1111/j.1654-1103.2012.01420.x.

Ruppert, J.C.,  F. Ewert, A. Linstädter, 2012. Drivers of dryland productivity - insights from a global meta-analysis. Proceedings of the EcoSummit 2012, September 30 to October 5, Columbus, Ohio, USA, pp. 345-345. https://elsevier.conference-services.net/resources/247/2695/pages/general.pdf

Ruppert, J.,  A. Linstädter, 2011.  Aboveground Net Primary Production and Rain-use Efficiency in Drylands - Results and Insights from a Meta-analytical Perspective.  Tropentag, Oktober 2011. Proceedings of  the Tropentag Conference, October 5-7, 2011, Bonn. http://www.tropentag.de/2011/abstracts/links/Ruppert_1xrqE232.pdf

Ruppert, J.,  A. Linstädter, 2010. Rain-use efficiency: A concept revisited. Recent challenges and possible approaches. In: Wolters, V., J. Groh, F. Peter, R. Waldhardt (eds.), Proceedings of the 40th Anniversary Conference of the ecological Society of Germany, Austria and Switzerland, 30 August - 3 September 2010, Gießen, Germany, 18-18. https://www.bayceer.uni-bayreuth.de/gfoe2010/en/program/5001/15450/BookOfAbstracts.pdf

Ruppert, J.,  A. Linstädter, 2010. Analyzing the rain-use efficiency: New insights by meta-analysis and quantile regression. Ecological Society of America Proceedings of the 95th Annual Meeting of the Ecological Society of America, 1-6 August 2010, Pittsburgh, USA. http://eco.confex.com/eco/2010/techprogram/P23633.HTM