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Publication review: Early assessment of seasonal forage availability for mitigating the impact of drought on East African pastoralists


In East Africa, households that rely on rainfall to sustain their livelihoods are significantly affected by the climate variability and frequent droughts brought on by climate change. Pastoralist households, especially those with small herd sizes, are particularly vulnerable to climate shocks. Drought-related livestock losses due to forage reduction, increase in mortality rate and epidemic diseases heavily affect pastoralists, leaving them exposed to poverty.

The CGIAR Research Program on Dryland Systems recognized and addressed the pressing need for mitigation strategies to reduce the impacts of drought on pastoralists in East Africa. In Kenya and southern Ethiopia, our scientists designed and developed Index-Based Livestock Insurance (IBLI), an insurance product based on the strong correlation between vegetation cover and livestock losses.

The recently published article “Early assessment of seasonal forage availability for mitigating the impact of drought on East African pastoralists” identifies options to improve IBLI’s index measurements, for the sake of providing pre-loss protection insurance options in place of post-loss pay-outs.

The existing IBLI model used in Kenya and southern Ethiopia is based on an area-aggregated seasonal forage scarcity index.  This index is derived from satellite-derived normalized difference vegetation index (NDVI) time series. The NDVI composites, which indicate whether the target area contains live green vegetation, are spatially averaged per administrative unit, temporally averaged for season and subsequently compared between years.

Until recently, fixed season timing and duration was used for the whole area for calculating the index.  This meant that:

  • March-September was the timing window for long rain seasons
  • October-February was the timing window for short rain seasons

To compare forage availability, both wet and dry season NDVI data were included within the index. Consequently, potential indemnity pay-outs were made late in the season, when livestock may have already died due to fodder scarcity. The authors suggested improving forage availability measurements to create a more cost-effective alternative to post-mortality intervention. This could be done by shortening the temporal integration period of the index.

To this end, a phonological analysis of NDVI time series was performed to obtain a location-specific estimate of season start- and end-dates. These dates were averaged per insurance unit to get unit-specific growing period definitions. The authors included only NDVI data for the period when forage is developing and discarded the data for the dry season. Using these shortened seasonal definitions, a new forage scarcity index was calculated.

The approach used by the authors significantly improved the IBLI’s forage scarcity index. This enhanced the efficacy of insurance schemes. In fact, the earlier assessment of seasonal forage scarcity can allow for earlier pay-outs, which could help better prepare pastoralists for drought-related risks.

In this way, pastoralists can invest in mitigation strategies, like purchasing fodder, water or medicines, aiming to protect their livestock instead of replacing it. This approach is more cost-effective and less disruptive, and can be replicated in other regions where insurance programmes are used to increase the resilience of farmers against climate change and drought-related damages.

Read the full article here.


The study reviewed in this blog was conducted under the framework of the CGIAR Research Program on Dryland Systems. The study was authored A. Vrieling, M. Meroni, A. G. Mude, S. Chantarat, C.C. Ummenhofer, K. (C.A.J.M.) de Bie.

About the author

Martina Antonucci is the Science Communications and Knowledge Management intern at the CGIAR Research Program on Dryland Systems.