Effects of pyrogenic factor on wetlands of Petrovskaya Pad' (Jewish Autonomous Region, Russia)

In recent decades, a severe wildfire situation threatening the territory along the periphery of the Bastak State Nature Reserve (Russia) has developed in the Petrovskaya Pad'. In this paper, we assessed the current state of the vegetation cover and post-pyrogenic changes in the Petrovskaya Pad', based on the geobotanical survey during a joint expedition in 2009. At present, this area of the Middle Amur Lowland is a vivid example of wetland degradation due to the repeated wildfire impact initiated by the local people and agricultural workers in the Amur region. The widespread xerophytisation process of fen vegetation, due to a sharp drop in the groundwater level, was observed. A comparison with the data of previous studies led to the conclusions that now mesotrophic shrub-Sphagnum bogs, described earlier, have completely disappeared from the vegetation cover of the territory. We suggest that their degradation is caused by the continuously acting pyrogenic factor. In addition, the paper for the first time provides data on the dynamics of the acrotelm structure in the post-pyrogenic period, which were obtained during a nine-year monitoring. The profound changes in the acrotelm structure are responsible for the restoration of mesotrophic bogs taking decades.