The Study of Interrelation Between the Number of White Mistletoe (Viscum Album L.) and Waxwings (Bombycilla Garrula L.) in Urban Landscape

Abstract

White mistletoe (Viscum album L.) is an evergreen hemiparasitic dwarf shrub which is known to cause deterioration of tree health. In anthropogenic landscapes of Kharkiv waxwings are the main agent distributing white mistletoe, so the definition of the relationship between the number of white mistletoe and birds of this species is relevant at this time. Thus, the aim of the study was to determine relationship between the number of the white mistletoe and its frugivoruos birds (the Waxwings) in urban landscapes. The authors carried the field survey in the city of Kharkiv (Ukraine). In this study we applied the results of dendrochronological analysis of radial increment of the Silver Mapple (Acer saccharinum L.) model trees. The changes in number of mistletoe shrubs over time and their distribution by age in retrospect were identified on the base of field data and by the application of matrix model of Viscum album population dynamic. The analysis of time series was conducted in order to determine relationships between radial growth of trees and the abundance of the Mistletoe's avian dispersers. In this study we applied parametric methods of analysis (Pearson coefficient of correlation). In the case of the city of Kharkiv, the white mistletoe number depends on the waxwing's seasonal abundance. We have got the following results. Firstly, white mistletoe sub-populations with semi-quantitative indexes 3 and 4 appeared on the host trees no later than in 1988, with semi-quantitative index 5 – no later than 1973, and with semi-quantitative indexes 6 – no than in 1954. Secondly, the autocorrelation analysis of the mistletoe and the waxwing time series proved the reliability of data. It is found that the white mistletoe number weakly relates to the abundance of the waxwing. To conclude, white mistletoe number depends on the waxwing's seasonal abundance. Further research should be directed to the developing of environmentally sound recommendations on the white mistletoe population management in urban ecosystems.