Colonization History, Phylogeography and Conservation Genetics of the Gravely Endangered Tree Species Hagenia abyssinica (Bruce) J.F. Gmel from Ethiopia

Hagenia abyssinica (Rosaceae) is a monotypic, African, dioecious broad-leaved tree whose pollen and seeds are dispersed primarily by wind. Fossil pollen records indicate a late-Pleistocene immigration into Ethiopia from the south. Chloroplast haplotypes fall into two lineages that mirror their geography, showing a striking match between spatial distribution and genealogical relationships. The chloroplast genetic pattern reflects restricted seed flow, contiguous range expansion, mutation, and occasional long-distance dispersal. Across populations, AFLP markers reveal moderate to high genetic diversity together with moderate yet significant differentiation—signals consistent with substantial gene flow after colonization. Despite wind-mediated dispersal, several stands exhibit a pronounced fine-scale spatial genetic structure (SGS).

Building on these insights, the study introduces a weighted-score population prioritization matrix (WS-PPM) that integrates genetic, morphological, and demographic criteria to rank stands for protection and domestication. It argues for immediate conservation action and extensive planting programs to secure the future of the gravely endangered “Kosso,” while enhancing its ecological functions and sustainable economic value.