Changes in the distribution of bryophytes in a highly urbanised region in Western Europe (Flanders, Belgium): a species-traits analysis

ABSTRACT

Introduction

In densely populated, highly industrialised regions such as Flanders (northern Belgium), species are under significant environmental pressures arising from air pollution, land use changes, and climate change, which affect distribution patterns and species abundance.

Methods

We compared bryophyte distribution data for 1980–1999 and 2000–2019. Species traits data were analysed to detect general trends in changes in occupancy for different species of moss and liverwort.

Key results

Species occupancy increased for epiphytic species of both mosses and liverworts. Liverwort species growing on dead, decorticated wood declined, whereas the number of mosses growing on this substrate increased. Liverworts decreased in all terrestrial habitats except artificial stones and other rocky substrates. Occupancy increased for mosses growing on peat substrates and on hard natural rocks. Changes in occupancy among groups of taxa classified according to Ellenberg values showed that liverworts of wet or moist habitats declined compared with those of dry habitats. Liverworts of warmer regions increased; however, for those characteristic of cold climates, there was no significant change.

Conclusions

Improvements in air quality, particularly due to reduced SO₂ and NO_x emissions, has allowed epiphytic bryophyte species numbers to recover. Among terrestrial species, there has been a decline in the number of liverwort species especially, and particularly those adapted to wet, cold conditions. This is probably due to longer and more frequent drought periods during summer, coupled with rising ambient temperatures. Larger, more robust wetlands and forests could be created to mitigate against this decline, these habitats being very fragmented in Flanders.

KEYWORDS:

• Air pollution
• climate change
• Ellenberg indicator values
• grid mapping
• liverwort
• moss
• substrate preference

Acknowledgements

We especially thank the members of the Bryological and Lichenological Society of Flanders (Werkgroep Bryologie en Lichenologie) for supplying the data on bryophyte distribution in Flanders for the past 40 years. We also thank the Meise Botanic Garden and the University of Ghent for the access to their herbaria (BR and GENT, respectively). We finally thank Quentin Groom for his review of our English grammar and two anonymous reviewers for their constructive comments on an earlier version of the manuscript.

Disclosure statement

No potential conflicts of interest were reported by the authors.

Additional information

Funding

No funding was obtained for this project.

Notes on contributors

Wouter Van Landuyt

Wouter Van Landuyt is a botanist at the Research Institute for Nature and Forest (INBO), Brussels, Belgium. His research focuses on plant ecology, phytogeography, and changes in plant distribution.

Hans Van Calster

Hans Van Calster is a statistician, with a background in forest ecology, working at the Research Institute for Nature and Forest. His research interests include statistical ecology, vegetation ecology, forest ecology and conservation management. He supports and promotes the use of open and reproducible research tools in science.