Simulation of the Effect of the Tundra Vascular Plant Canopy on the Productivity of Four Plant Species

Abstract

The physical environment and the structure of the vegetation are two important components which influence the nature and stability of tundra ecosystems. Low temperatures, low solar and infrared irradiances, high wind speeds, permanently frozen subsoil, and impeded water drainage restrict the development of the vegetation by affecting plant growth and development, vegetation composition, and soil faunal activity and decomposition (Bliss, 1956; Billings and Mooney, 1968; Price, 1971; McCown, 1973; Savile, 1972). The vascular plant canopy, although short, affects the solar and infrared irradiances, wind speeds, and air and surface temperatures at the moss or organic mat surface, and the depth of thaw (Drury, 1956; Price, 1971; Matveyeva, 1971; Brown, 1973; Dingman and Koutz, 1974; Miller et al., 1976; Ng and Miller, 1977). Thus, within the interactive vegetation-soil systems, the structure of the vascular plant canopy influences the production of the vascular plant and the production and distribution of moss species, by affecting the microclimate of the vascular plant canopy and moss. This chapter analyzes, by simulation models, the effects of the vascular plant canopy on microclimate and the effect of microclimate on production by vascular plants and moss.