Wind-driven mechanisms for allometric growth of Spartina alterniflora leaves: Implications for adaptive management

Abstract

Spartina alterniflora not only has service functions but also causes ecological disasters; hence, it should be managed adaptively rather than eradicated. The laminae and leaf sheaths differ in functions and the wind pressures on the two plant components are different. Thus, it is inferred that differences in allometric growth between the leaf sheaths and laminae occur in regions with different wind speeds: the laminae become smaller than the leaf sheaths in high-wind-speed regions; the laminae become larger in low-wind-speed regions. To verify this inference, the leaf traits of S. alterniflora along the Xiaoqing River and in the Tiaozini Wetland were investigated. The leaf traits varied with study area: they presented distinct allometric growth curves between laminae and leaf sheaths; the lamina length and area, dry weight of the leaf sheaths, and dry weight of the laminae in the Tiaozini Wetland were smaller than those along Xiaoqing River; S. alterniflora tended to have large leaf sheaths and small laminae in the Tiaozini Wetland. Thus, wind speed affects the allometric growth between the leaf sheaths and laminae, and the lamina size in the high-wind-speed area tend to miniaturize. Measures that can further reduce the lamina size in high-wind-speed areas or enlarge the lamina size in low-wind-speed areas are detrimental to the survival and proliferation of S. alterniflora, and can be used for adaptive management.