Medicinal service supply by wild plants in Samburu, Kenya: Comparisons among medicinal plant assemblages

Supply of medicinal plants from African landscapes is crucial because of their widespread use. Rapid climate change and land use change are potential threats to this resource but knowledge about the ecological needs of many of these plants is still rather limited. More knowledge about potential threats to medicinal plants supply and options to prevent future losses are desirable. Therefore, the objectives of the study were to examine (1) the effects of environmental drivers on the occurrence of medicinal plant species, (2) how different vegetation formations contribute to the provision of plants used for the treatment of diseases and (3) how these contributions are secured by redundancy. The analysis was based on a sample of 130 sampling plots in Samburu County, Kenya. We identified patterns in medicinal plants co-occurrences using classification and ordination analyses and analyzed these pattern in terms of environmental drivers, service diversity and service security. The pattern in medicinal plants co-occurrences reflected the distribution of broad formations (bushed grassland, forest, wooded grassland, savanna) driven by differences in grazing pressure, drought, slope and fraction of sand in soils. Each of the formations brought with it its own characteristic endowment with medicinal plants. The formations differed in the diversity and security of medicinal services provided. All resulted as fulfilling unique services with diseases treated by plants occurring exclusively in one or another formation. Forests featured the highest diversity of medicinal services, with medicinal plants used against 67 diseases. The supply security in forests, resulting from redundancy in supply provision, was moderate. In contrast to this, savanna grasslands featured plants with uses against 49 diseases, some of them were treated exclusively by plants from savanna grasslands. This formation also showed the highest redundancy. Wooded grasslands showed very little redundancy and is likely to be adversely affected by climate change. Whereas savannas feature the largest pool of medicinal plants and should receive due attention, urgent and highest conservation priority should, presently and in future, go towards the wooded grassland that had the lowest supply redundancy for traditional medicine

Climate change impacts on the availability of anti-malarial plants in Kenya

In many rural East African areas, anti-malarial plants are commonly used as first-line treatment against malaria. However, spatially explicit information about the future availability of anti-malarial plant species and its relation to future suitable habitat for malaria vectors is limited. In this study we (1) model the distribution of anti-malarial plant and malaria vector species and assess the drivers of their distributions taking the example of the Samburu dryland in Kenya, (2) map the modeled overlap in this area, (3) assess the impact of future climate change on anti-malarial plant and malaria vector species and (4) report their future overlaps. Our results show that mean temperature of warmest quarter, precipitation of wettest quarter and mean temperature of coldest quarter were the most important environmental variables that affected the distribution of anti-malarial species. The effects of climate change will vary, with some areas characterized by huge losses in anti-malarial species habitat while others gained or remained stable under both SSP2-4.5 and SSP5-8.5 climate change scenarios by 2050s and 2070s. According to most of our scenarios, more than half of the anti-malarial species will become vulnerable or threatened by 2050s and 2070s. A comparison between distribution patterns of future anti-malarial species richness and malaria vector species suitable habitat suggests that the former will decrease considerably while the later will increase. Because the availability of anti-malarial species will decrease in the areas affected by malaria vectors, geographically targeted conservation strategies and further control measures against malaria vectors are all the more important