Genetic Diversity and Population Structure in the East African Pencil Cedar, Juniperus procera (Cupressaceae)

Abstract Juniperus procera is a long-lived quality timber species that is endangered in its entire African distribution and listed as lower risk near threatened (LR-nt) in IUCN Red Data List for Malawi. It is characterized by extremely small and widely isolated populations, with very low regeneration rates. In Malawi, it is a protected tree and only a few natural individuals remain. It has been subjected to repeated fires and extraction for long periods. Malawi is the most southerly known population of Junipers in the southern hemisphere and is far south of its equatorial optimal environment. These factors are expected to exert influence on the distribution of genetic diversity in J. procera. The level of genetic diversity in turn, has implications for the long term survival of Junipers in East Africa. Like many other African species however, its conservation is until now based largely on taxonomic and descriptive ecological information. In this study, a novel fingerprinting technique, AFLP, was employed to determine levels of genetic diversity,assess for population structuring and differentiation in order to provide basic data for better management actions. The material studied was obtained from three countries: Malawi, Kenya and Ethiopia Results indicate that levels of genetic diversity are more or less equal across the sampled distribution area (gene diversity 0.111 0.229). The populations are genetically structured according to geographical origination, with high within population genetic diversity (83% 98% within countries). Two major groups were documented in the data: the first group including Ethiopian and part of Kenyan material, and the second, including Malawian and the rest of Kenyan material. The largest genetic distance was observed between the Malawian and Ethiopian populations. Each major group was further split into two sub-groups. These results and potential implications for the long-term survival and management of J. procera are discussed. It is concluded that small and peripheral populations of J. procera, such as those occurring in Malawi, are as viable genetically as larger populations growing in optimal equatorial environments. Keywords: Juniperus procera, AFLP, genetic diversity, population structure, differentiation, managemen