Article by KWR researcher in Nature
Phosphorus threatens survival of rare plants
Plant species that persist in areas with low availability of phosphorus invest little in sexual reproduction. Due to the increase of phosphorus in their habitats and the fragmentation of low-phosphorus areas, these plant species, which already are on the “red list”, are under threat of extinction. This is the conclusion of research by KWR’s Yuki Fujita and her university colleagues. The scientific journal Nature publishes the findings.
“These plant species are trapped in the few low-phosphorus areas that are still around.”
It has long been known that tens of plant species on the “red list” are threatened by the increase of phosphorus in their habitats. These species are common in low-fertility soils, such as dune valleys, wet grasslands and peat bogs. It was, however, unclear why these particular species were so vulnerable. To find out why, Fujita and her colleagues investigated 491 plant species in 599 low-fertility natural ecosystems in 9 countries across Europe and in Siberia.
“We discovered that plants that are able to survive in low-phosphorus soils invest little in sexual reproduction,” explains Fujita. “They don’t flower, or do so only for a short period of time, and produce few seeds. This is a useful adaptation in those conditions, as sexual reproduction organs require lots of phosphorus.” However, this adaptation makes these plant species extra vulnerable, since low-fertility ecosystems are becoming scarcer and more scattered. “These species produce so few seeds that they have difficulty spreading out across large distances,” says Martin Wassen from Utrecht University, who led the research. “This means they are essentially trapped in the few low-phosphorus areas that are still around. In order to prevent them from going extinct, we need to take urgent measures.”
Many soils are phosphorus-saturated and it will take decades to recover the original levels. As with nitrogen, there should be statutory regulations for phosphorus, according to the researchers. Furthermore, the existing low-fertility natural ecosystems should be adequately protected. In a number of areas with high levels of phosphorus, the soil can be restored through water management and sod-cutting. “In the end,” says Wassen, “we can only preserve these unique plant species if Europe invests in a sufficiently robust and close-knit network of low-fertility nature reserves.” The conclusions complement broader KWR research into the effects of climate and water management on vegetation.
© 2017 KWR Watercycle Research Institute
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