As grasslands get abandoned, controlled burning is discussed as a labor-saving method of keeping forests at bay.
As grasslands get abandoned, controlled burning is discussed as a labor-saving method of keeping forests at bay. A Kobe University research team found that this method results in higher biodiversity and a higher prevalence of endangered plant species in some grasslands compared to others, depending on what soils they grow on.
Humans have been keeping grasslands since millennia by grazing, mowing and controlled burning, all of these are means to keep forests from overgrowing the grasslands. Grazing and mowing are, however, labor intensive and as rural areas become increasingly depopulated, grasslands have been disappearing worldwide. One consequence of this is the loss of the habitat of plant and insect species, also many endangered ones, that depend on grasslands. To maintain grasslands nevertheless, “prescribed” burning, which is what land managers call controlled burning, is being discussed as a labor-efficient option. But not all grasslands are equal. The Kobe University ecologist USHIMARU Atushi says, “Many studies have focused on examining the effects of different management measures on plant diversity, but few researchers have paid attention to those of soil differences.” Therefore, it has remained unclear which soils are better candidates for being managed by prescribed burning in terms of allowing a high diversity of endangered plants or plant species in general.
To settle this question, Ushimaru’s team led by master’s student ASADA Airi turned to Mount Fuji. There, on a training site of the Japan Self-Defense Forces, grasslands covering different soil types are kept by prescribed burning once a year in April. “We noticed that there were some areas, especially on young lava flows, where endangered species were concentrated,” Ushimaru explains the choice of the research site, allowing them to study which soil factors influence species abundance. On site, they set up 100 one-square-meter plots across the grasslands on four different soil types and in each identified all plants as well as measured a range of physical and chemical factors.
Read more at Kobe University
Image: In their paper published in Plants, People, Planet, ASADA Airi and her team report that grasslands on young lava flows (pictured) exhibit higher total species richness, native species richness and prevalence of red-listed plant species than grasslands on both young and old scoria bedrock. (Credit: ASADA Airi)
