Phenotypic diversity of spruce populations in some Protected Areas in Eastern Europe and Siberia

Abstract

In many Protected Areas of Eastern Europe and Siberia, the European spruce (Picea abies) or Siberian spruce (Picea obovata) plays a significant role in plant communities. Difficulties in determining the specific and intraspecific diversity of spruce in Protected Areas occur in the zone of natural (introgressive) hybridisation of spruce. Since the time of Ledebour's studies, the main diagnostic feature of these spruce species is the shape of the upper part of seed (cone) scales. The European spruce has an angularly acuminate and noticeably elongated cone scale, while the cone scale of the Siberian spruce has a close to rounded form and it is less elongated. In East-European spruce populations, formed under introgression influence, this trait has an intermediate character. The shape of the upper part of spruce seed scales remains constant throughout the whole tree life. And it is characterised by a high variability within populations and between different populations. Nowadays, the study of the phenotypic diversity of the spruce populations is performed using visual descriptive assessment, i.e. subjectively. Consequently, disparate results are often obtained even for the same study areas. The applying of metric assessment of a trait and the consequent distinguishing of the phenotypes of individuals allow to perform mathematical processing of the results and to obtain objective data about the population structure. We aimed to study the phenotypic diversity of spruce in Protected Areas in Eastern Europe and Siberia on the basis of metric assessment primarily of the shape of seed scales. The determination of the coefficient of narrowing (Cn) and coefficient of projection (Cp) of the upper part of seed scale can be considered as the most objective method to study this diagnostic trait. The difference between these coefficients (Cn‒Cp) is a more informative indicator to characterise properties of individuals, populations and their groups. In Eastern Europe and Siberia, we distinguished nine areas of distribution of different population groups (or phenotypes): P.e., P.eem., P.em., P.emm., P.m., P.mms., P.ms., P.mss., P.s. They are characterised by an average value of the Cn‒Cp indicator: -50%, -40%, -30%, -20%, -10%, 0%, 10%, 20%, 30%, respectively. On the basis of this gradation in populations, we adopted a similar gradation of individuals' phenotypes: e, eem, em, emm, m, mms, ms, mss, s. On the basis of study of the spruce population diversity in Protected Areas in Eastern Europe and Siberia, considering phenotypes identified by the metric traits of seed scales, we found that all of them significantly differed in terms of all analysed traits. In the National Park «Belovezhskaya Pushcha», Carpathian Biosphere Reserve, Central Forest State Natural Biosphere Reserve, and Oksky State Natural Biosphere Reserve (European range of spruce), we found the highest cone length, highest phenotype frequency of European spruce individuals (60–100%). In these Protected Areas, there are no or very few intermediate phenotypes, and no Siberian spruce phenotypes. The Lapland State Natural Biosphere Reserve, Visimskiy State Natural Biosphere Reserve, Yuganskiy State Nature Reserve, Sokhondinskiy State Natural Biosphere Reserve, and Vitimskiy State Nature Reserve formed the opposite group according to all indicators studied. These Protected Areas are located within the range of the Siberian spruce. They are characterised by predomination (63–100%) of phenotypes of Siberian spruce individuals, while there are no European spruce phenotypes. We established the predominance of intermediate spruce phenotypes in the State Nature Reserve «Kologrivskiy Les», National Park «Chavash Varmane», Volzhsko-Kamskiy State Nature Biosphere Reserve, and Pinega State Nature Reserve. Of them, the first two Protected Areas are a bit closer to European spruce phenotypes, while the second two Protected Areas are characterised by similarity to the Siberian spruce phenotypes. The objective, sufficiently tested method to study the spruce population phenotypic diversity can also be used inother Protected Areas.

Keywords

• national park
• nature reserve
• phenotypic diversity
• picea abies
• picea obovata