Questions: In some fire-prone ecosystems, bryophytes play a crucial role by providing the surface fuel that controls the fire-return interval. Afroalpine heathlands are such an ecosystem, yet almost nothing is known about the bryophytes in this system. We do not know the level of species richness, or if there is a successive accumulation of species over time, or if some species are adapted to specific phases along the successional gradient, for example early-successional species sensitive to competition.

Location: Afroalpine heathlands in Ethiopia

Methods: We made an inventory of all bryophytes in 48 plots of 5 x 5 m, distributed along a chronosequence from 1 to 25 years post-fire. The heathlands are located around 3500-3800 m asl, and are managed by traditional pasture burning with fire intervals of around 8-20 years.

Results: We found in total 111 taxa of bryophytes. Post-fire mortality was almost 100%. The youngest plots had only a few cosmopolitan species often found after fire. Species richness increased monotonically and seemed to start levelling off at around 15 years after fire, when many plots had around 30 species and a high cover of Breutelia diffracta, which is a key ground-living species, important as surface fuel. Most species were found with sporophytes, a pattern even stronger for the most frequent species.

Conclusions: Interestingly, bryophyte diversity is already remarkably high by only 15 years after total eradication. The relatively slow accumulation of species in the first years suggest that dispersal in space, and not time, is the major mechanism by which sites regain their diversity (i.e. spore banks play a small role). This indicates that the high species richness is built up through colonization from surrounding heathlands, and perhaps also from higher altitude alpine grasslands and lower altitude forests, and that the bryophyte diversity in this system is maintained by the traditional fire and grazing management.

48 sites with a 5 x 5 m plot in each site were inventoried for all bryophytes. A number of environmental and explanatory variables were collected in each plot. See the methods section of the paper and the ReadMe-file for more information.

See further the Paper, Supplementary information and the ReadMe file.