Format: ORAL

Martha Kandziora1*, Diana L. A. Vasquez2, Christian Brochmann3, Abel Gizaw3, Petr Sklenr1, Filip Kolr1,2, Nicolai M. Nrk4,, and Roswitha Schmickl1,2

1 Department of Botany, Charles University, Prague, Czech Republic 2 Institute of Botany, The Czech Academy of Sciences, Pruhonice, Czech Republic 3 Natural History Museum, University of Oslo, Oslo, Norway 4 Department of Plant Systematics, Bayreuth Centre of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany

Niche packing and niche specialisation are two central factors modulating biodiversity patterns across latitudes and altitudes. Niche packing is when species niches are finely packed in a multi-dimensional niche space while occurring in the same geographic space. Specialised species on the contrary should have narrow, separate niches and are highly adapted to certain environmental conditions. Both phenomena enable species to coexist by avoiding competition via resource partitioning. Here, we combine phylogenomics of six plant lineages, with occurrence records to compare niche and range metrics - size and overlap - of species between the highly diverse tropical alpine habitats of the South American Andes and the less species-rich alpine habitats on the eastern African mountains. Comparing species niche sizes between both continents using a multidimensional climate space, we found that overall niche size is larger in the Andes than in the mountains of eastern Africa. Additionally, range-overlapping species in the Andes showed generally less overlap in niche space than in Africa. Taken together, we hypothesise that biodiversity differences between the two tropical alpine ecosystems might be caused by different degrees of competition.