A general framework to describe the alteration of natural tree species composition as an indicator of forest naturalness. (June 2017)

• Record Type: Journal Article
• Authors: Bončina, Andrej; Klopčič, Matija; Simončič, Tina; Dakskobler, Igor; Ficko, Andrej; Rozman, Andrej
• Is Part Of: Ecological indicators. Volume 77(2017)
• Page Start: 194
• Page End: 204
• Publication Date: 2017-06
• Subjects: Natural forest vegetation -- Index of dissimilarity -- Human influence -- Landscape matrix -- Topographic variables -- Susceptibility to natural disturbances; Environmental monitoring -- Periodicals; Environmental management -- Periodicals; Environmental impact analysis -- Periodicals; Environmental risk assessment -- Periodicals; Sustainable development -- Periodicals; 333.71405
• DOI: 10.1016/j.ecolind.2017.01.039
• Languages: English
• ISSNs: 1470-160X

Abstract

Highlights: The suggested procedure enables estimation of tree species composition alteration. The alteration was primarily the result of past land use and forest management. The alteration decreased along the gradients of rockiness, inclination and elevation. Greater alteration appeared in areas closer to forest edge. The alteration increased the susceptibility of forest stands to natural disturbances. Abstract: The alteration of natural tree species composition is defined as the deviation of the current tree species composition from that of the natural state. It can be used as a measure of human influence on forest vegetation, and thus as an indicator of the naturalness of forest vegetation. The aim of the study was to develop a standard procedure for estimating the alteration of natural tree species composition, to explain factors driving alteration and to examine its significance for susceptibility of forest stands to natural disturbances. The alteration of natural tree species composition was estimated for the Dinaric region (5556 km 2, Slovenia) by the Robič Index of Dissimilarity ( RID ), ranging from 0 (completely natural) to 100 (completely altered). The index was calculated on the compartment level (24 ha each on average) with data on current and potential natural forest vegetation. The influence of human activities on tree species alteration was examined by using topographic and accessibility variables. The susceptibility of forest stands to natural disturbances was analysed with data on sanitary felling. In the study area, the natural tree species composition of forest stands is moderately preserved; the average value of RID was 50.05, ranging from 1.76 to 100, and the coefficient of variation was 0.49. The alteration of the natural tree species composition of forest stands is primarily the result of forest management and past land use, conditioned either by topography or accessibility of forests. The degree of alteration of tree species composition decreased along the gradients of rockiness, inclination and elevation. A greater degree of alteration appeared on the slopes of intermediate and south facing aspects than on north facing slopes, and in areas that were closer to the forest edge. A higher level of alteration significantly increases the susceptibility of forest stands to natural disturbances. The procedure represents a novel approach in modelling the alteration (naturalness) of tree species composition of forest vegetation. It is applicable at different spatial scales and fosters an understanding of the patterns of tree species composition under the influence of human activity across forest landscapes.