United, we stand, divided, we fall: ramet aggregation changes the growth and size structure of two riparian plants in Lijiang River under waterlogging stress

Rui-Hua Liu, Qiu-Wen Chen

Monday 29 june 2015

17:39 - 17:42h at Europe 1 & 2 (level 0)

Themes: (T) Hydro-environment, (ST) Ecohydraulics and ecohydrology, Poster pitches

Parallel session: Poster pitch: 3G. Environment - Ecohydraulic

Many types of human-mediated disturbances, occurring at (and driven by processes that occur at) scales from local to global, influence riparian ecosystems. However, few studies have explicitly tested the effects of intraspecific aggregation of offspring ramets on the growth and size structure of plant populations under the waterlog stress pressure. Therefore, this study conducted a filed survey on the distribution pattern on the dominant species - Digitaria ciliaris and Chrysopogon aciculatus along Lijiang River with the waterlogging stresses varience. Their interspecific relationships on different waterlogging stress levels were studied using Ripley' L function in point pattern analysis and Programita software. Meanwhile, a greenhouse experiment was conducted, in which two populations of eight offspring ramets of tthese two species were grown aggregately or segregately in two waterlogging levels. The results showed that the growth inhibition during the 40 cm waterlogging treatment was more pronounced for shoots than for roots. Ramet aggregation is unfavorable to the growth of D. ciliaris in a nonstressful environment, while the spatial pattern of ramets of C. aciculatus did not have significant effect on their growth. The broader riparian zones of D. ciliaris are determined by its high ramet aggregation leading to greater tolerance to waterlogging, allowing it to exist in the inundated strips.