Tree species effects on bryophyte guilds on a reclaimed post-mining site

Abstract

Tree species effects in afforestation of post-industrial lands have important impacts on biodiversity of restored sites. We aimed to assess tree species effects on bryophytes in a novel ecosystem – a reclaimed lignite mine spoil heap. We investigated bryophyte species pools in tree stands of six species: Alnus glutinosa, Betula pendula, Pinus sylvestris, Quercus robur, Q. rubra and Robinia pseudoacacia in two substratum groups: epigeic and epiphytic species. We assessed beta-diversity among tree stand types and bryophyte guilds. We also analyzed impacts of light availability, pH and C/N ratios of bark and soil, annual litterfall and bark water capacity of the main tree species, on bryophyte species pools among tree stands and species groups, using canonical correspondence analysis. Our study revealed tree species effects on bryophyte species richness, beta-diversity and composition. Main mechanisms connected with tree species effects were light availability and substratum C/N ratio, as well as substratum pH and bark water capacity. We confirmed that tree species traits connected with C/N ratios and light availability affect bryophyte species composition. Guilds of bryophytes responded differently to tree species effects on ecosystem properties and their turnover differed between tree stands. Influence of the factors studied on species pools was similar to those reported from mature woodlands. Presence of many woodland specific bryophytes has shown restoration success ca. 30 years after afforestation of post-industrial land. Different tree species provided different habitats for bryophytes, and therefore decisions regarding what tree species to plant affect restoration success and the future bryophyte species pool.