Komarov Botanical Institute, the Russian Academy of Sciences, St. Petersburg, Russia
The data on alien plant invasions in the regional floras of European Russia are represented significantly uneven and this has been pointed out in the most recent research (Vinogradova et al. 2018). To fill this data gap and to satisfy current needs of invasion biology, a number of regional inventories should be carried out, particularly across the boreal forest zone. In the central part of European Russia, Kostroma is among the least developed regions, with natural and seminatural forest vegetation covering about 70% of the area. The ongoing inventory of alien plants in the Kostroma region is a project aimed to improve the understanding of current trends in plant invasions in the boreal zone of European Russia. The inventory is based on herbarium collections and published data covering the last 130 years of floristic records and intensive field work was implemented between 2011–2018.
To date, at least 250 alien vascular plant taxa were reported as naturalized in the Kostroma flora, of which 40 are invasive. Fifteen invasive alien species (IAS) have successfully spread across the entire region. The alien-rich sites were strongly associated with several urban areas, and railways seems to be the most important vector spreading neophytes. At the same time, the expansion of IAS is limited, presumably due to climatic factors as well as by the presence of suitable habitats. Primarily they inhabited coastal environments and abandoned arable lands, while forested areas remained sustainable for invasion. A large number of IAS that are common in more temperate regions of European Russia have not yet naturalized in Kostroma. This delay might be related to the slowing of IAS spreading along the south to north gradient. Thus, the boreal forest zone serves as a barrier sifting out the most successful IAS. Considering this, two questions should be answered: (i) are there significant differences in the distribution and naturalization of IAS in the adjacent biogeographical regions, namely boreal forests and hemiboreal ones, and (ii) what influences invasion success more, climatic factors or the urbanization rate in a region?
The main outputs of this project include: (i) the establishment of an extensive database of Kostroma IAS, (ii) revealing the regional spatio-temporal patterns and assessing impact of IAS, and (iii) improving regional nature conservation and policy making. This project also intends to focus on plant invasion patterns in the boreal zone of European Russia and to bring new insight on IAS spreading across latitudinal gradients. We presume that the low representation of boreal regions in Russian IAS inventory may lead to a biased assessment of the IAS spatial and temporal patterns in the boreal forest zone, and the Kostroma region may serve as a model area to study plant invasions in the southern limit of the boreal forest.