Effects of Traditional Vegetation Usage and Management on the Growth of Facilitator Keystone Species in a Moist Tall Grassland

To reveal the influence of traditional management measures on the growth of Ischaemum aristatum var. glaucum, whose facilitation effects on plant species diversity have been addressed in our previous studies, experimental winter-mowing and burning treatments were implemented in Ukishima Marsh, a conservationally important freshwater lowland reed marsh of eastern Japan. Comparison of environmental conditions among burnt, mown, and control zones revealed that winter burning, which was even more effective than mowing, created well-illuminated conditions, a high cumulative ground-surface temperature, and a wide range of daily temperature fluctuations. Relative growth rates of I. aristatum var. glaucum shoots and individuals showed a significantly ascending gradient in the order of control, mown, and burnt zones. Continuation of traditional vegetation usage and management is recommended for Ukishima Marsh, as such methods would not only provide favorable environmental conditions for native herbaceous plants commonly, but would also indirectly maintain plant species diversity through promotion of plant facilitation as demonstrated in our previous studies.