What are the most serious threats? The world-wide reduction in and degradation to wildlife habitats is leading to a loss of species richness and genetic diversity. In principle, three major types of changes threaten bryophyte habitats: complete habitat destruction (e.g. clear-felling); habitat degradation through lack of, or inappropriate, management, and pollution. Threats to bryophytes include destruction of natural forests, afforestation with exotic species, reclamation of land, urbanisation, road and dam building, mining, drainage of wetlands and over-grazing. Invasive, introduced plants can bring devastation to native bryophyte floras. Also fragmentation of habitats caused by the increased use of land is impoverishing the diversity of the bryophyte flora.