Study of the University of Coimbra identifies variables that control drought effects on streams
Some of the variables studied included the type of aquatic community involved in litter decomposition in streams
English version: Diana Taborda
The study “A meta-analysis of drought effects on litter decomposition in streams”, coordinated by the Department of Life Sciences, Faculty of Sciences and Technology of the University of Coimbra (DCV-FCTUC) identified moderator variables that control drought effects in streams. Furthermore, it was possible to quantify the relationship between plant litter and the percentage of flow reduction as well as the percentage of dry riverbeds days.
Verónica Ferreira, leader of the study and researcher at MARE - Marine and Environmental Sciences Centre of FCTUC, explains that, among all moderator variables analysed, it was possible to conclude that “the type of aquatic community involved in litter decomposition conditions its response to natural drought (not human-induced), with a stronger reduction -about 54% - when litter decomposition involves both micro-organisms and invertebrates than in microbial-only mediated litter decomposition, in which the inhibition is about 22%".
Climate was another variable identified, concluding that “it influences litter decomposition in human-induced drought (e.g., as a result of water abstraction for drinking or agriculture), with stronger reduction in warm and humid (66%) areas than in temperate and Mediterranean climates (33 – 36%)”.
To achieve the main objective of this research (to identify which variables can potentially mitigate or exacerbate the effects of drought periods on streams), the team used meta-analysis to collect all the scientific evidence on the effects of drought periods on plant litter (leaves, woods, etc.) decomposition in streams, a key process as it sustains the aquatic food web and is crucial in the carbon and nutrient cycles.
The scientific article is available here.