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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. 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. 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. Improvements in air quality, particularly due to reduced SO2 and NOx 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. [ABSTRACT FROM AUTHOR]

We studied the spatial variation of plant assemblages in a 4383 ha deciduous forest in the periphery of Brussels. All vascular plant species were recorded following a grid-map of 1 km2-cells totally or partly covered by the forest. A total of 414 plant species was observed. Species composition and plant functional groups in forest edges and the neighbouring forest interior are studied. The study quantifies plant functional groups (e.g. ancient forest plants, true forest species, rare species, geophytes, C, S or R-strategists) in the plots and tests for relationships with the geographical position in the forest according to a city-to-forest gradient. Our results led us to identify distinct characteristics of forest flora based on the distance to the actual city border. The study revealed significant outer edge effects on the flora. Plant composition of the forest interior and forest edge can be separated by ordination on species composition, suggesting that these two biotopes have a distinct species assemblage. χ2-test and Two-Way-Indicator-Species-Analysis detected significant edge-associated species that were recorded exclusively in the edge or were the most frequent in the forest edge. We found that forest stands close to urban areas support populations of indicators of disturbance (pioneer species, C and R-strategists and aliens) to plots which are distant from the city. However, our observations also suggest that species groups with high conservation value (e.g. ancient forest species, or rare species) may also be more represented at the edge than in the core of the forest. Moreover, no forest specialists which would occur only in the interior zone were found. These observations are in disagreement with the hypothesis that true forest plants and species groups of high conservation value would be more frequent in the forest than on the borders. These findings are applicable to the management of forests in an urban context. [Copyright &y& Elsevier]