When forests of flowering plants offered new habitats

One of the theories that make it possible to explain this diversification outburst after the Cretaceous is based on the appearance of the first forests of flowering plants during this period. “These forests facilitated the creation of new habitats for already existing plants and could have marked the beginning of the broad diversification of bryophytes”, explains Benjamin Laenen. Analysis of the phylogenetic tree created in the context of this study also shows a second diversification outburst of bryophytes around 30 million years ago. “These results prove that mosses and liverworts continue to evolve even though they resemble very primitive plants in terms of their morphology”, continues the scientist. It should not be assumed that because it is difficult to tell the difference between a moss today and those of 200 million years ago that these plants have not evolved or that their evolution is slower. The different species of bryophytes continue to propagate and the current species are recent. “Our results make it possible to refute the idea that bryophytes are threatened by more recent plants. This is certainly not the case, these plants evolve together”, explains Benjamin Laenen. His research has made it possible to study the impact of this type of sexual system (hermaphrodite/separate sexes) on mosses and their diversification. This research work will certainly soon be the subject of another publication…

The ecological role of bryophytes

Why bother studying bryophytes? “This is a question I am often asked”, answers the amused researcher. “Firstly, this is because they are not well known and they were the pioneering plants on Earth. They therefore developed in very different conditions to those we know today and adapted over time”, continues Benjamin Laenen. “But also because, for example, the vegetation of the Great North is mainly made up of sphagnum which constitute the largest carbon sink in this part of the globe”, he indicates. “In addition, bryophytes actively participate in the regulation and purification of water, the protection of soils against erosion or against biomass production by peatlands in particular”. They therefore play a crucial environmental role. Often used as a bioindicator of pollution, bryophytes are very sensitive and are threatened by the increasing pollution due to industrialization. While not necessarily emblematic, there are still good reasons why bryophytes should attract the attention of scientists and anyone else interested in the history and future of our planet…