2022 Volume 27 Issue 1 Article ID: 2117
Solfatara fields, which form around fumaroles (vents) in hot springs and volcanoes, are characterised by extreme environmental conditions, including volcanic gas emission, low pH, and high aluminum content in soils. Very few plant species are capable of tolerating these conditions. Recently, Andropogon virginicus L. (Poaceae), an exotic grass native to North America, has colonised solfatara fields in Kyushu, Japan, but these populations have not been well assessed. We assessed the status of A. virginicus in 13 solfatara fields in Kyushu and its distribution relative to soil pH. We examined further germination and seedling growth under low pH conditions using laboratory experiments. We found that A. virginicus was present in 6 of the 13 survey locations, and that its distribution was partially overlapping with that of Fimbristylis dichotoma (L.) Vahl subsp. podocarpa (Nees et Meyen) T. Koyama (Cyperaceae), an endangered species endemic to Kyushu. Laboratory experiments indicated that germination and seedling growth were uninhibited at a pH of 3, suggesting high potential for establishment of A. virginicus in acidic soils. Thus, the invasion of A. virginicus may endanger endemic species and pose a threat to the unique landscapes of solfatara fields. We suggest that prompt action be taken to control the spread of this species.
