Characteristics of successful competitors: an evaluation of potential growth rate in two cold desert tussock grasses

摘要: Within the first few weeks after seedling emergence, Agropyron desertorum, a more competitive tussock grass, had much higher mean relative growth rate (RGR) than spicatum, very similar, but less species. However, beyond early stage, two grasses remarkably similar whole-plant RGR in hydroponic culture and aboveground glasshouse soil, if root temperatures were above approximately 12°C. At soil between 5 12°C, A. desertorum exhibited 66% greater spicatum (P<0.05). Both species responded similarly to warming temperatures. In field, however, tiller rates generally similar. Neither showed marked elongation until couple of snowmelt, by which time temperatures, at least depth 10 cm, 12°C for significant portion day. Aboveground biomass accumulation over three-year period indicated that both potential whereas Artemisia tridentata ssp. vaseyana, common neighbor planted same plots, rate. The ability adult as compared cannot be attributed appreciable differences rates.