Base mineral inflow in a remnant cool‐temperate mire ecosystem

Abstract

Kiushitou (42°28′ N, 141°9′ E) is a lowland mire located in a residential area of northern Japan. We examined the 2‐D distribution of hydrochemical variables and their seasonal changes in relation to plant communities in an attempt to conserve the Sphagnum fen (Sphagnum subfulvum). This mire is gently sloping and the upper area consists of alder and ash forests, while the lower area is covered with fen communities. The grassy fen, Moliniopsis japonica, occurs throughout the lower area, whereas the Sphagnum fen is restricted to the southwest part of the mire. anova and canonical correspondence analysis revealed that the occurrence of Sphagnum fen is negatively correlated with Mg, Ca and electrical conductivity (EC). These variables indicated that water in the upper forest area contained a high concentration of minerals from the neighboring residential area. Seasonal changes in EC values revealed that the watercourse from a spring point in an upper corner to the lowest drainage ditch was divided into two, southwest and northeast, courses. Because the northeast‐course spring water joins mineral‐rich water flowing from a point at the upper margin, the northeast part of the lower area contains considerable Ca and Mg. In contrast, the mineral‐poor spring water flowing into the southwest part of the mire ensures the survival of the Sphagnum fen. Thus, when we stop the supply of mineral‐rich water from the upper margin the area of the Sphagnum fen will expand into the northeast part of the mire. Two‐dimensional details of the hydrochemical regime clarify the impact of mineral inflow and the expansion mechanisms of these minerals.

Microenvironmental conditions for Japanese alder seedling establishment in a hummocky fen

“…Hummocks are characterized by less litter cover and are suitable places for the establishment of alder seedlings. In general, the pH of groundwater in alder forest is approximately 5-7 (Yabe and Onimaru 1997;Yabe and Nakamura 2002;Asada 2002;Tsuyuzaki et al 2004). The soil pH of hummocks in alder forest at our study site was thus notably low.…”

Key factors controlling the size, biomass, and sprouting of Japanese alder swamp forest in Kushiro Mire, Hokkaido, Japan

“…Although it is well known that species composition and plant productivity in northern mires are influenced by hydrochemical factors (Bridgham et al 1996;Wheeler and Proctor 2000), recent studies have analyzed the hydrochemical factors that might influence vegetation changes in Japan (Yabe et al 1999(Yabe et al , 2001Yabe and Nakamura 2002). Although ecological information for restoration is accumulating day by day, restoration of mire vegetation has been done without sufficient scientific information about habitats, sprouting characteristic, and life history traits of plant communities (Nakamura 2003).…”