Global Warming Favors the Development of a Rich and Heterogeneous Mycobiota on Alien Vines in a Boreal City under Continental Climate

Abstract

The species richness and composition of macro- and microfungi on vine species in the parks of Ekaterinburg City (the Ural macroregion, Russia) located in the southern boreal vegetation subzone in a continental climate was studied. The average annual air temperature has increased by 3.1 °C since the beginning of the 20th century; therefore, the conditions for the growth of vines have improved. These conditions include warmer winters and, consequently, less frost damage to perennial plants. Due to the warmer climate, the area of vines grown in the city has increased five times over half a century, and the yield of grapes has grown 3.7 times. The alien East Asian vines are the most dominate vine species cultivated, while European, North American, and native plant species, including archaeophytes, together only represent a handful of the species cultivated. At the same time, 65% of the area of woody vines in the city is covered by a North American species, namely Parthenocissus quinquefolia. An increase in the number of vine species, their biomass, and covered areas contributes to an increase in the number of fungal species growing on these vine species. In total, 81 species of phytopathogenic and 87 species of saprobic macro- and microfungi have been recorded during the century-long history of mycological research in Ekaterinburg City. Mycobiota of vines in Ekaterinburg City is biogeographically heterogeneous and 1.1–3.2 times richer in comparison with ones of the regions located on the northern limit of natural ranges of the vines. Recorded macrofungi (Basidiomycota) are predominantly present on native boreal species; however, some exotic tropical and subtropical East Asian fungal species (that have not ever been recorded on other substrates in the natural forests of the Urals and Siberia) are found here too. Recorded microfungi are highly specialized vine-associated species (mainly Ascomycota) that are widespread within the natural ranges of the vines and absent in the boreal zone of Eurasia: there are 63 vine-associated species (15 macro- and 48 microfungi) in Ekaterinburg that are not found in the Urals on other substrates. Many of these species have been recorded for the first time in this study, so we consider that they invaded Ekaterinburg City in the last 20 years, likely due to the warming climate observed over the last decades in the region. There are 19 and 32 species of phytopathogenic fungi collected in the families Cucurbitaceae and Vitaceae, respectively. During the past 40 years, the recorded fungal species richness has increased by 16% on Cucurbitaceae, as well as 37% on grapes. In this study, the distribution of vine-associated fungi, including phytopathogenic fungal species, from the nearest regions of ancient vine culture (Southern European Russia and the Caucasus, Central Asia, the south of the Russian Far East) to the boreal regions of the Urals were investigated. The increase in the range of these phytopathogenic fungal species can lead to significant economic losses to the regional agricultural sector.