Long-term dynamics of landscapes of the North-Western Ladoga Region according to the stationary observations

Abstract

The results of 25 years of observations (1992–2017) on 20 permanent key plots (PKP), founded near Priladozhskaya educational-scientific field station of St. Petersburg University (150 km North of St. Petersburg) are analyzed. The PKP are located in the landscape of North-Western Ladoga Region, in the most typical landscape sites: on the tops and slopes of selga (ridges composed of Archean and lower Proterozoic granitoids and treated by glacier), terraces on lacustrine clays and loam, peat bogs of various types, etc. When locating the PKP, typical plant communities were chosen (pine, spruce, mixed and small-leaved forests, pine woodlands, overgrown meadows) and the most characteristic impacts (forest fires, selective cuttings, windfalls, recent use in agriculture, drainage, and others). The most dynamic landscape in the North-Western Ladoga Region are terraces on lacustrine clay and loam, for a long time used in agriculture. Currently, processes of overgrowing realized at a 7 landscape-dynamic trajectories are taking place. In other landscape sites, changes of a long-term state are initiated mainly by fires and windfall, and subsequent processes of forest regeneration. In addition, the change of tree species in forests can occur when small-leaved trees reach their maximal biological age. The landscape sites of upper slopes of ridges and drained peat bogs with a predominance of pine forests in the absence of catastrophic impacts are the most stable.