skip to content

MetaRUE - Meta-Analysis of Aboveground Net Primary Production and Rain-use Efficiency in (semi-)arid ecosystems


MetaRUE is a PhD project which is carried out by Jan Ruppert at the Range Ecology and Range Management Group, University of Cologne, and the Crop Science Group, University of Bonn. The work is funded by the Foundation of German Business (Stiftung der Deutschen Wirtschaft e.V., sdw).

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 trigger 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.

The 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 recommend land-use practices and will be incorporated in dynamic vegetation models at the Crop Science Group, INRES University of Bonn.

Person in charge:

Dr. Jan Ruppert[1,2]

Person(s) involved:

PD Dr. Anja Linstädter[1,2], Prof. Dr. Frank Ewert[2], Prof. Dr. Michael Bonkowski[3]


2011 – 2014


Foundation of German Business (Stiftung der Deutschen Wirtschaft – SDW)

Cooperating partner(s):

[1] Range Ecology and Range Management, Botanical Institute of the University of Cologne
[2] Crop Science, Institute of Crop Science and Resource Conservation of the University Bonn
[3] Terrestrial Ecology, Zoological Institute of the University of Cologne

PhD Thesis:

Ruppert, J.C. 2014. Advancing Functional Understanding of Primary Production in Drylands: Insights from a Data-Integration Approach. Universität zu Köln.


Ruppert, J.C., Harmoney, K., Henkin, Z., Snyman, H.A., Sternberg, M., Willms, W., Linstädter, A., 2015. Quantifying drylands’ drought resistance and recovery: The importance of drought intensity, dominant life history and grazing regime. Global Change Biology 21(3): 1258-1270. DOI:

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

Ruppert, J.C., F. Ewert, Linstädter, A. 2012. Drivers of dryland productivity – Insights from a global meta-analysis. EcoSummit 2012, Sept 30th - Oct 5th 2012, Columbus OH, USA. [Page 345]

Ruppert, J.C. & Linstädter, A. 2011.  Aboveground Net Primary Production and Rain-use Efficiency in Drylands - Results and Insights from a Meta-analytical Perspective.  Tropentag, Oct 5th - 7th 2011, Bonn, Germany.

Ruppert, J.C. & Linstädter, A. 2010. Rain-use efficiency: A concept revisited. Recent challenges and possible approaches. 40th Anniversary Conference of the Ecological Society of Germany, Austria and Switzerland (GfÖ), 30th August - 3rd September 2010, Gießen, Germany.

Ruppert, J.C. & Linstädter, A. 2010. Analyzing the rain-use efficiency: New insights by meta-analysis and quantile regression. 95th Annual Meeting of the Ecological Society of America (ESA), Aug 1st - 6th 2010, Pittsburgh PA, USA.