Tropical mountain forests are hotspots of biodiversity that are widely threatened by human population pressure and climate change. However, the cryptogamic species richness of many tropical mountain regions is insufficiently known, the poorly understood biodiversity of tropical African lichens being a prime example. To study the diversity of the genus Peltigera (Ascomycota, Lecanoromycetes) in East Africa, we studied lichens in a wide range of habitats on the slopes of Mt Kilimanjaro in Tanzania. Ranging from savannah to alpine heath vegetation and from natural forests to agricultural environments, 13 habitat types were sampled for lichens, which were then identified based on the nuITS genetic marker and morphology. We found eight Peltigera species on the slopes of Mt Kilimanjaro, including P. alkalicola sp. nov., P. dolichorhiza, P. polydactyloides, P. praetextata, P. rufescentiformis, P. seneca, P. sorediifera and P. ulcerata. Peltigera is most common and species-rich in the subalpine Erica forest zone, and four of the eight detected species were present only in the subalpine and alpine vegetation zones. Peltigera alkalicola was identified as a previously undescribed species, growing on trachybasaltic lava in the subalpine and alpine zones of Mt Kilimanjaro. The species resembles P. lepidophora but differs by possessing smaller thalli and peltate isidia that are distinctly dark on the lighter, tomentose lamina. Based on data from the NCBI GenBank, P. alkalicola probably also occurs in Alaska (USA) and Ningxia (China). This suggests that even though the species might generally be rare, it may have a global distribution in extreme mountain environments. For the first time, we report P. sorediifera from Tanzania and P. seneca from Africa.

Plant functional types across environmental gradients can be considered as a powerful proxy that reveals vegetation–environment relationships. The objectives of this study were to investigate the response in the relative abundance of plant functional types along altitudinal gradients and to examine the relationship of plant functional types to environmental variables. The study was conducted in the Gughe-Amaro Mountains, in the south-west Ethiopian highlands. We established 74 plots with an area of 400 m2 (20 × 20 m) each along altitudinal ranges between 1000 and 3000 m asl. Data on site environmental conditions and on the abundance of plant functional types were analysed using the constrained linear ordination technique (RDA) in order to identify the relationships between plant functional types and environmental variables. Altitude, soil organic carbon, soil sand fraction and surface stone cover were significantly related to the relative abundance of plant functional types across the gradient. Tussocks and thorns/spines were abundant in lower altitudinal ranges in response to herbivory and drought while rhizomes and rosettes were abundant at higher altitudes in response to the cold. Generally our results show that topographic attributes (altitude and slope) as well as soil organic carbon play an important role in differentiating the relative abundance of plant functional types in the investigated gradient. Thus, considering specific plant functional types would provide a better understanding of the ecological patterns of vegetation and their response to environmental gradients in tropical regions of Africa prone to drought.