Characteristics of the seeds and cones of Serbian spruce - indicators of species endangerment

A significant amount of existing research indicates a persistent trend of declining populations and trees of the Serbian spruce ( Picea omorika /Pančić/Purkyně), a tertiary relict, rare, endangered, and protected species. Understanding the characteristics of cones and seeds, along with the analysis of intra- and inter-population variability, is crucial for identifying the reasons for this decline and implementing in situ and ex situ conservation measures to preserve this species. During 2022/23 (autumn/spring), cones were collected from 111 trees of this species. The trees are distributed across seven natural populations and one urban population in Bosnia and Herzegovina. Immediately after collection, the cones were measured, processed, seeds were extracted, and germination tests were conducted. Significant differences among the tested trees and populations were found for all measured cone traits. The germination results indicate very low seed viability, averaging 57,03% for all tested trees, with the percentage of empty seeds at 26,85%. Significant differences in germination were also observed at the population level, ranging from 20,40% to 81,14%, with the percentage of empty seeds ranging from 8,10% to 59,60%. The results suggest that endangered populations with a small number of trees have significantly smaller cones, a higher percentage of empty seeds, and lower germination rates. Such a low germination rate in natural populations of Serbian spruce indicates the need for urgent actions to protect this species and assist its natural regeneration (in situ), as well as to establish plantations outside its natural range (ex situ conservation).