Spatial distribution of some alien plants across a restricted mountainous area

Abstract

Plant invasion of natural ecosystems is one of the most serious ecological crises of our time. The invasive plants are one of the causes for native species decline and ecosystem degradation. This study tries to answer the question whether studied mountainous area is relatively free of plant invasions. We also try to provide a clue about the possible causes for the current invasion state of the studied territory. We used direct ordination, correlation and multiple regression techniques coupled with different statistical tests to describe the current invasion pattern of the studied vegetation. We found that the most invaded vegetation types are lowelevational mixed xerophilous and subxerophilous oak forests and pine plantations. The open subalpine communities are relatively uninvaded. Alien species richness is highest in the xeric habitats at low elevations and in the mesic ones at higher elevations. The common beech forests in the mesic habitats at low to middle elevations are almost completely free of invasion. The leading factors, driving invasion processes in the area are thought to be the anthropogenic and natural disturbances, placed in the context of main local environmental gradients like elevation, habitat moisture and slope inclination. Understanding the factors that drive mountain vegetation invasion helps us taking timely actions to prevent further degradation of precious natural habitats around the globe.