UV radiation and reduced rainfall: Legacy effects on litter and first-year decomposition in two Mediterranean evergreen shrubs

作者：Claudia Rodríguez-Hidalgo, Laura Llorens, Anna Doménech-Pascual, Anna M. Romaní, J.F. González, Dolors Solé Verdaguer · 发表于：Environmental and Experimental Botany · 年份：2025 · DOI：10.1016/j.envexpbot.2025.106307 · 研究领域：Light effects on plants、Biocrusts and Microbial Ecology、Polar Research and Ecology

Climatic models for the Mediterranean Basin predict higher ultraviolet (UV) radiation and drier conditions by century’s end, potentially altering litter traits, early-stage decomposition, and nutrient cycling. This study investigates how UV radiation (UV-B and UV-A) and reduced rainfall influence leaf litter characteristics and its decomposition in two evergreen sclerophyllous Mediterranean species, Arbutus unedo and Phillyrea angustifolia, growing in a natural shrubland. A field litterbag decomposition experiment was conducted using litter from plants growing in eighteen 9 m 2 plots arranged in three blocks. For six years, plots experienced one of three UV radiation conditions: ambient UV, without ambient UV-B, and without ambient UV, combined with two rainfall levels (natural or reduced). Treatments altered the initial leaf litter chemistry. In A. unedo, UV-B exposure decreased the leaf carbon/nitrogen (C/N) ratio (due to higher N) under natural rainfall, while in P. angustifolia , mainly UV-A radiation increased this ratio. Over the studied decomposition period (374 days), leaf litter mass loss in both species was limited, but P. angustifolia litter lost more mass (11%) than A. unedo litter (3%), likely due to a lower C/N ratio and a higher microbial activity. UV-A and UV-B radiation affected early litter decomposition in both species by altering recalcitrant compounds and/or microbial biomass, though effects on A. unedo depended on the rainfall amount. Overall, UV radiati...