More than a fifth of all known plant species on earth are under serious threat from extinction, according to the latest State of the World’s Plants report by the Royal Botanic Gardens, Kew.
The report, estimating that the total number of known vascular plant species stands at 391,000, identifies a range of factors influencing the number of endangered plants, including changes in land use, invasive species, and climate change. Land use changes, specifically deforestation in mangrove and tropical forest biomes to make room for shrimp farming, palm oil plantations and other agricultural activities are a major driving force in the destruction of these ecosystems and their flora. The roughly 4,979 invasive plant species are also a significant factor affecting the longevity of host ecosystems through the disruption of native floral communities. Although climate change has a relatively minor impact on plant extinctions, this is likely to increase significantly in the next few decades with growing impacts on crucial hydrological systems, changing the availability of water resources and impacting plant extinction rates.
Although the threat to more than 20% of plant species is likely to impact the global economy, the scope of the impact is difficult to predict. A minimum of 31,128 plant species, 8% of all known vascular flora, are directly useful to human activities. Additionally, plant use is dominated by medicines (17,810 species), materials such as textiles (11,365), and environmental uses such as erosion restriction (8,140). Perhaps interestingly, only 17.8% of useful flora are human food sources, pointing to the highly varied use of plants.
Despite the grim forecast, the report points to positive developments in the identification of new plant species; 2,034 vascular species were discovered in 2015 alone. These discoveries are likely to grow in importance as vulnerable domesticated flora lacking in genetic diversity, unable to cope with rapidly changing environments, are increasingly faced with extinction.
Image credit: The Guardian