Факторы, влияющие на разнообразие лишайников в усадебных парках Псковской области

Abstract

The article describes the results of studies of the factors affecting lichen diversity in 46 manor parks of the region of Pskov. The investigated parks were founded in the end of XVIII – beginning of XX centuries. Twenty of them are fragmented and currently occupy less than 5 ha, the area of nine parks varies from 5 to 10 ha, those preserved within historical boundaries cover from 11 to 100 ha. Manor parks are situated both within the settlements’ boundaries (31 parks) and outside the settlements either bordering forest (12) or agricultural lands (3). Ten of the former border the forests. During the study 166 lichen species were identified. Statistical methods were performed to investigate the factors affecting lichen diversity in manor parks. Linear regression analysis was used to examine the dependence of the lichens species number on the park age/date of park creation (dispersion pattern), area of the parks (box plot), substrata diversity (dispersion pattern), and the dependence of the epiphytic lichens species number on tree and shrub species diversity (dispersion pattern). With the biserial correlation coefficient the impact of the settlement and the presence of the surrounding natural forests was calculated. Correlation analysis was performed to demonstrate the colligation between lichen species composition of the parks located in different subzones of forest zone in the region of Pskov. Our findings show that the number of lichen species depends on the park area (p = 0,0315), the variety of substrate types (p ˂ 0,001), and the variety of trees and bushes planted (p ˂ 0,001). The date of park creation and the presence of the surrounding natural forests do not influence the species diversity of lichens. We reveal that the location of the parks in a specific subzone of forest zone (southern taiga and mixed coniferous-broad-leaved forest) has no significant effect on the lichen species composition. The species richness of lichens tends to decrease in parks located within the settlements. The data obtained indicate not only the similarity of the species composition of lichens in the studied communities, but also the long-term development of lichen park communities in comparable climatic and landscape conditions.