St. Petersburg

Peter the Great initiated a gigantic experiment to change an inhospitable natural wetland landscape into a major city and port by the construction of drain-age canals and buildings, the spreading of fertile soil and the planting of millions of broad-leaved trees. During Soviet times the city was surrounded by high-rise apartment blocks. The city is now a UNESCO World Heritage Site. The historic parks and gardens have the highest plant biodiversity of all the urban biotopes in the central areas although the most common biotopes are associated with walls, buildings and embankments. There are six protected areas (2,150 ha) comprising unique native habitats and which contain the most rare species and "pure" undisturbed examples of natural habitats. The recent shift to a market economy and the consequential increase in air pollution has seen a decrease in lichen biodiversity and degradation of urban soils. The shift has also resulted in the sub-urbanisation of the city caused by a change in emphasis from public green space in the Soviet era to the large private gardens of affluent people. St. Petersburg is following international trends in landscape design; all the plant material for new public and private sectors is sourced from 'western' nurseries and based mainly on non-native, fashionable "global" taxa, as a consequence the urban flora is also becoming standardised.