Annual patterns of litter decomposition in the channel and riparian areas of an intermittent stream

Abstract

Intermittent streams, dominant in arid and semi-arid regions, are suggested to be more representative of the global river network than perennial rivers. Even so, the impacts of constant changes in hydrological regime on the functioning of these streams and riparian areas remain to be elucidated. In this study, two native deciduous litter species were used to compare microbialdecomposition patterns between the channel of an intermittent stream and its riparian area over one year. Overall, the stream channel presented higher decomposition rates and fungal biomass than the riparian area, for both litter species. Despite a prolonged absence of streambed surface water (254 days), differences in hydrological conditions in the wetter seasons (autumn and winter) led to lingering effects, shaping and differentiating decomposition dynamics in both zones throughout the whole hydrological cycle. As the present results highlight the importance of the "hydrological imprint" for the leaves degradation process, long term studies seem to be advisable over short-term ones to better understand the functioning of intermittent streams.

Hidden Decomposers: the Role of Bacteria and Fungi in Recently Intermittent Alpine Streams Heterotrophic Pathways

“…Furthermore, the increasingly frequent occurrence of low-flow phases and dry events in a wide variety of streams and rivers worldwide has emphasized the need to understand how in-stream microbial communities respond to changing flow conditions. Desiccation due to the absence of flowing water can affect stream microbial communities associated with leaf decomposition, by delaying or severely retarding it, thus disrupting heterotrophic energy pathways [ 34 , 35 ].…”

Effects of hydrological regime on Taxodium ascendens plant decomposition and nutrient dynamics in the Three Gorges Reservoir riparian zone

“…Many studies have shown that the chemical properties and nutrient status of leaves are important factors affecting the rate of foliage decomposition in rivers (Gessner et al, 2010;Alvim et al, 2015). In addition, abiotic factors such as hydrological regimes also significantly affect foliage decomposition (Anderson and Smith, 2002;Sun et al, 2012;Simões et al, 2021). Different flooding conditions often produce different physical and chemical environments (Behzad et al, 2022), which in turn regulate the decomposition rate of leaves (Anderson and Smith, 2002;Xie et al, 2016;Chen et al, 2020).…”