Quantitative response of leaf‐litter decomposition rate to water abstraction in a gradient: Implications for environmental flow management

Abstract

Water abstraction significantly impacts streams and rivers, in turn affecting ecosystem structure and function. Previous studies have mostly focused on the response of structural indicators (e.g., invertebrate community composition) to water abstraction but have often neglected the indicators of ecosystem processes (e.g., decomposition rates). In this study, we investigated the relationship of leaf‐litter decomposition rate (k) with flow reduction in a manipulated ecosystem experiment. The flow reduction rate across our experimental reaches was about 25%. The results showed that water diversion significantly reduced the discharge, width and depth of the stream, but did not affect water quality. The leaf‐litter decomposition rate varied from 0.001day‐1 to 0.026 day‐1 and decreased along with flow reduction. The results elucidate the impact of water abstraction on the decomposition of leaf‐litter in streams. A quantitative relationship between the flow rate (Q) and the decomposition rate (k), mathematically expressed as k = 0.0231 exp(ΔQ1.232), was derived. Furthermore, a framework was developed for setting the minimum environmental flow based on the assessment of river health by using leaf‐litter processing rates.

The succession of bacterial and fungal communities during decomposition of two hygrophytes in a freshwater lake wetland

“…1). Many previous studies reported that the frequent alternation of inundation and stranding, the increase of stream flow, and the shoal water flooding all increased the decomposition rates, especially at the early stage of decomposition (Dolinar et al 2016, Zheng et al 2018b, Huang et al 2018). Moreover, Zheng et al (2018b) found that the duration of early‐stage inundation had a greater influence on the litter decomposition rate than the later stage inundation.…”