Impact of Mixing on the Structural Diversity of Serbian Spruce and Macedonian Pine Endemic to Relict Forest Communities in the Balkan Peninsula

Aleksandar Popović,Snežana Obradović,Biljana Šljukić,Damjan Pantić,Milan Medarević

doi:10.3390/f12081095

Abstract

The aim of this paper is to analyze the effect of different degrees of mixing on the diversity structure in stands left to spontaneous development. The research included two communities of species endemic to the Balkan Peninsula—the Serbian spruce (Picea omorika Pančić Purk.) and the Macedonian pine (Pinus peuce Griseb). Data from eight sample plots were used in the research. The changes in diameter and height structure, spatial arrangement of trees, and diameter differentiation were analyzed. The analyzed parameters of structural diversity show relatively low to moderate values. Results showed an increase in mixing was reflected in the width and shape of distributions. A spatial analysis of stands with a higher degree of mixing showed a tendency towards a random to regular distribution of individuals, in contrast to stands with a lower degree of mixing which showed a tendency towards a clump distribution. The pronounced species’ dimensional and spatial diversity confirms their importance to the condition of modern forest management. Significant differences in the change of structure are shown by stands with a share of admixed species of above 20% by volume. The obtained results refer to stands left to spontaneous development, suggesting than an active research and management approach must be assumed to realize the goal of protecting rare forest ecosystems.

Highlights

The most important relict-endemic forest ecosystems of the Balkan Peninsula are the communities of Serbian spruce (Picea omorika) and Macedonian pine (Pinus peuce)
Structural parameters have been assessed as very good indicators of biodiversity and are recommended as its direct measure [4,5]
The structural diversity of the studied relict-endemic communities confirms their great importance in terms of biodiversity and reifies their need for protection and conservation in the Balkans

Summary

Introduction

The diversity of vegetation of the Balkan Peninsula, in a broader context, can be explained by its position where diametrically opposed climatic influences meet and affect the area [1]. The most important relict-endemic forest ecosystems of the Balkan Peninsula are the communities of Serbian spruce (Picea omorika) and Macedonian pine (Pinus peuce). Anthropogenic impacts in the past have reduced the range of Serbian spruce to small and inaccessible habitats along the middle course of the Drina River (Bosnia and Herzegovina, Serbia) and Macedonian pine to habitats of the highland region (Bulgaria, Serbia, Macedonia, Montenegro, Albania, and Greece) (Figure 1) [2]. The character of habitats in which these communities develop, the passive approach to their protection, as well as the absence of economic interests, have resulted in poor research of these ecosystems [3,4]

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