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Rangeland Management in Face of Drought - the DroughtAct Experiment

The DroughtAct experiment addresses two main research questions:

(1) What determines rangelands’ stability in the face of drought?

(2) What are suitable management interventions to avoid degradation?

DroughtAct t is located at the experimental farm of the University of Limpopo, South Africa (Figure 1). It combines rainfall and grazing treatments (Figures 2 & 3), simulating realistic climate conditions under future climate change regimes in conjunction with potential management interventions. The experiment is part of the International Drought Experiment (IDE), initiated by Drought-Net, a global network to assess terrestrial ecosystem sensitivity to drought.

Details on the experiment

  • We simulate a severe drought in combination with different resting schemes
  • The experimental treatments are replicated four times (Figure 1)

A pilot study for a network experiment on joint grazing and drought effects
The DroughtAct experiment is also a pilot study for an extension of the International Drought Experiment (IDE). With this grazing add-on, it will be possible to study combined grazing and drought effects over a broad range of terrestrial ecosystems to better understand their potentially interactive effects on ecosystems functioning and ecosystem service provision.

The grazing add-on also allows transferring the IDE approach (that requires undisturbed sites) to ecosystems which are subject to herbivory by wild or domestic herbivores. The sampling procedures of DroughtAct are fully compatible with the core IDE protocol. You can download our sampling protocol with the grazing add-on to Drought-Net [here].

If you are interested in the DroughtAct approach, contact Anja: Anja.Linstaedter(at)uni-koeln.de

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Figure 2: Temporal grazing exclosure-cage with soil moisture probe. Cages allow for accurate estimation of aboveground net primary production (ANPP) under grazing conditions. The scattered soil moisture probes (white cap in foreground) allow for mid- to high-resolution monitoring of temporal and spatial patterns of plant available water.

 

 

 

Figure 3: Rainout shelters simulating a centennial-scale drought (intercepting 66% of rainfall). Each shelter is 6 m x 6m in size. Trenches filled with impermeable membranes avoid below surface water run-on, hence, the typical rooting-zone of grasses is detached from the surrounding soil-moisture.