Morphometric traits and sexual dimorphisms do not strongly differentiate populations of Zeravshan juniper (Juniperus seravschanica Kom.) in Kyrgyzstan

Intra- and among-population variations of Juniperus seravschanica were morphologically examined in eight populations originating from elevations of 1300–2200 m a.s.l. in Kyrgyzstan. Eleven traits of needles and cones were studied on 70 vouchers. In addition, height, diameter, stem form, and sex of 172 trees were recorded in the field in order to test whether male trees invest more in vegetative growth than females and if sex ratio is shaped by (limited) environmental resources. Morphological differences among populations were small, but needle length, width and thickness were statistically different. However, differences based on needle traits were independent from geographical, altitudinal and environmental distances. In sharp contrast to studies in other Juniperus species, sex ratio in J. seravschanica was strongly female biased (3.5 females : 1 male). Moreover, no correlation between the habitat conditions and the sex ratio was detected, suggesting that within the altitudinal range of this species, females occur more frequently. This has implications for sustainable use and the conservation of J. seravschanica populations. It is likely, that due to the higher investment of male individuals in vegetative growth males are more exploited than females. An average effective population size of 70% of the respective census suggests that conservation measures and non-selective logging regimes are required to allow reproduction and a natural regeneration of this species.