The bryophyte flora of northern Iturup (north-west Pacific): between the circumboreal and East Asian floristic regions

ABSTRACT

Introduction. The Kuril Islands Chain demarcates the boundary between the circumpolar and East Asian floras in the amphi-Pacific and is a trans-Oceanic migration route from warm-temperate insular East Asia to north-east Asia and Beringia. This paper reviews the flora of the northern part of Iturup Island in regards to its bryogeography and taxonomic diversity, as well as its relative position among other bryophyte floras of north-east and East Asia.

Methods. The paper uses morphological methods to identify the species composition and detrended correspondence analysis to identify the position of the northern Iturup Island in the system of local floras of the eastern, extra-tropical, Pacific.

Key results. The flora is closely related to the bryophyte floras of the southern Kurils and Hokkaido Island, but has been found to be distinctly distant from the ‘true’ cool-temperate East Asian floras, as well as from the boreal and hemiarctic floras of north-east Asia. Instead, the floras of the south Kurils and northern Hokkaido Island belong to a peculiar intermediate phytogeographic province that cannot be unambiguously placed in either the East Asian or circumboreal floristic regions. The hemiboreal character of the bryophyte flora of northern Iturup Island is in contrast to the general appearance of many of the dominant vegetation communities on the island, which are more characteristic of the hemiarctic.

Conclusion. There is no robust evidence to refer the bryophyte flora of northern Iturup either to the circumboreal or East Asian Floristic Region, the flora belongs to a unique intermediate province between the two regions.

KEYWORDS:

• East Asia
• Kuril Islands
• liverworts
• mosses
• phytogeography
• Russian Far East

Acknowledgements

The authors are deeply indebted to John Atwood (MO) for correcting the English in the manuscript.

Notes on contributors

Vadim Bakalin. The input to this paper: material collecting, identification, general idea, writing and analysis. The research interests: East Asian liverwort floras, phytogeography of liverworts, taxonomy of Solenostomataceae and Lophoziaceae.

Vladimir Fedosov. The input to this paper: material collecting, identification, general idea, writing and analysis. The research interests: North Asian moss floras, phytogeography of mosses, taxonomy of some moss groups.

Olga Pisarenko. The input to this paper: material collecting, identification, writing and analysis. The research interests: mosses of local floras in Russian Asia, phytogeography.

Eugeny Borovichev. The input to this paper: material collecting, identification, writing and analysis. The research interest: liverworts of local floras of North Europe and Asia.

ORCID

Vadim Bakalin http://orcid.org/0000-0001-7897-4305

Additional information

Funding

This work was partially supported by the RFBR Grant 15-34-20101 (Field studies), RFBR 17-04-00018 (Laboratory studies and analysis of hepatics) and RSF 18-14-00121 (Laboratory studies and analysis of mosses).