Reduced soil contributes to the anomalous occupation of dwarf communities in N‐richer habitats in a cool‐temperate mire

Abstract

Spatial patterns of the oxidation–reduction potential (Eh) of soil, water level and chemistry were examined in the fen area of the Tohfutsu mire, northern Japan, where horse pasturage has been carried out throughout the growing season every year. The fen vegetation consisted mosaically of communities mono‐ or codominated by Eleocharis kamtschatica, Iris setosa and Carex lyngbyei. The highest concentration of total dissolved nitrogen of soil water was observed in the dwarf community dominated by E. kamtschatica with smaller biomass, whereas the nutrient level was lower in the community monodominated by C. lyngbyei with larger biomass. Principal component analysis denoted well that Eh, N, K, and pH contributed to the differentiation of these communities significantly. During the growing season that was investigated, the highest nitrogen concentration was observed in midsummer, when plants are expected to absorb nutrients intensely, indicating that the supply of dissolved nitrogen far exceeded the nutrient uptake of plants. Multiple habitats with reduced soil were formed by submergence and by an excess of nitrogen due to pasturage, and the soil reduction indirectly inhibited the incursion of species with large biomass at such sites. It was demonstrated that soil Eh contributed to the anomalous pattern of vegetation where the supply of available nitrogen exceeds the uptake by plants.

Zonation of plant cover and environmental factors in wetlands of the Sanjiang Plain, northeast China

“…In addition to the Carex lasiocarpa community, only the Carex pseudocuraica community is common elsewhere, such as in Hakkaido (Julve 1999) and Russia (Botch and Masing 1983). The other vegetation types are pseudo‐vicariant(s), for example, tussock‐forming communities such as Carex appendiculata and Carex meyeriana communities, are the vicariant of the North American Carex stricta type (Lord and Lee 2001, Peach and Zedler 2006, Rydin and Jeglum 2006), Japanese Carex caespitosa, C. angustinowiczii and C. middendorffii (Nakamura et al 2002, Koyama and Tsuyuzaki 2010). The wet meadow, Calamangrostis angustifolia–Carex appendiculata association is the vicariant of Canadian tussock meadow marsh with Calamagrostis canadensis and Carex stricta and shrubs (Rydin and Jeglum 2006).…”

Functional linkage between N acquisition strategies and aeration capacities of hydrophytes for efficient oxygen consumption in roots

“…Both N acquisition strategies led to optimum O 2 consumption in the two species with distinct aeration capacities and allowed them to show similar growth levels, which probably explains their coexistence in natural habitats. In wetlands, plant growth and distribution are strongly regulated by hypoxic stresses (Biemelt et al , Nakamura et al , Jampeetong and Brix ), and the coexistence of hydrophytes with distinct aeration capacities is commonly observed among many species, in addition to Z. latifolia and P. australis (Grosse , Pavlides ). Such coexistence can be simply understood by considering the O 2 consumption‐related traits of the roots and N acquisition strategies, as indicated in this study.…”

Hydrological influences on the distribution of vegetation and tree height of Alnus japonica (Thunb.) Steud. in the Kushiro Mire, Japan

“…It is well known that hydrochemistry is a key factor for controlling the distribution of vegetation in mires (Bridgham et al, 1996;Wheeler and Proctor, 2000). In particular, for Japanese floodplain mires, which are waterlogged throughout the year, hydrological factors, such as the oscillation of the water level, are extremely important (Yabe and Onimaru, 1997;Nakamura et al, 2002aNakamura et al, , 2002cNegishi, 2009). From these results, waterlogging is a key factor for controlling the distribution of alders and their morphology, such as the height of a tree.…”