Riparian forests are subjected to multiple disturbances, such as tree diseases caused by invasive pathogens, whose consequences on stream functioning are unknown. We assessed the impact of Phytophthora cinnamomi infection, and interactions with temperature, on microbial decomposition of Castanea sativa leaves. Leaves from healthy, symptomatic and highly symptomatic trees were incubated in the laboratory at 13 and 18 °C for 64 d. Infection significantly increased polyphenolic concentration and leaf toughness, reducing leaf decomposition and microbial respiration rates irrespective of temperature. Aquatic hyphomycete communities differed significantly in leaves from highly symptomatic trees. Fungal biomass was highest at 18 °C, irrespective of tree health status. None of the parameters were influenced by the tree health status × temperature interaction, suggesting that temperature rise may not synergistically increase the cross-ecosystem effects caused by P. cinnamomi in streams where litter decomposition is microbial-driven. Infection by P. cinnamomi alters the nutritional quality of leaves affecting the functioning of aquatic ecosystems.

河岸森林遭受多种干扰，例如由入侵性病原体引起的树木疾病，其对河流功能的影响尚不清楚。我们评估了疫霉菌感染的影响以及与温度的相互作用对栗树叶片微生物分解的影响。将健康，有症状和高症状树的叶子在实验室中于13和18°C孵育64 d。感染显着提高了多酚浓度和叶片韧性，降低了叶片分解和微生物呼吸速率，而与温度无关。叶片中的水生疏生菌群落与症状严重的树明显不同。不论树木的健康状况如何，真菌生物量在18°C时最高。这些参数均不受树木健康状况×温度相互作用的影响，这表明温度升高可能不会协同增加由枯草芽孢杆菌引起的跨生态系统效应，其中凋落物分解是微生物驱动的。肉桂假单胞菌感染 改变了叶片的营养质量，影响了水生生态系统的功能。