Impacts of water level fluctuations on detritus accumulation in Lake Baiyangdian, China

Decreases in water level could stimulate emergent plant growth and accelerate lake terrestrialization. To explore the impacts of hydrological variability on detritus accumulation in Lake Baiyangdian, a process-based ecosystem model was applied to investigate how emergent plants affect lake terrestrialization under changing water levels. Results of this study suggested that the accumulation of Phragmites australis (P. australis) detritus is one of the main factors that promote terrestrialization, accounting for 1.8 mm yr−1 of sediment increase in the lake from 2001 to 2010. Water level and temperature were the primary drivers of detritus accumulation. The impacts of water level variability on detritus accumulation in Lake Baiyangdian were further investigated through scenario analysis. Results demonstrated that both annual and inter-annual water level fluctuations could affect plant detritus accumulation. The scenario with low water level supported relatively high plant productivity and fast plant detritus accumulation, whereas the high water level scenario induced the lowest plant biomass production and slowest detritus accumulation. Enlarged inter-annual water level fluctuations also caused an increase in both plant productivity and detritus accumulation. This study suggests that the terrestrialization processes of lakes can be mitigated through regulating lake water levels to reduce detritus accumulation. Copyright © 2015 John Wiley & Sons, Ltd.