Spring stimulates leaf decomposition in moderately eutrophic streams

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• 作者：Ana Pereira ; José Trabulo ; Isabel Fernandes ; Cláudia Pascoal…
• 关键词：Eutrophication ; Season ; Leaf decomposition ; Aquatic hyphomycetes ; Shredders
• 刊名：Aquatic Sciences
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：79
• 期：1
• 页码：197-207
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Freshwater & Marine Ecology; Marine & Freshwater Sciences; Oceanography; Ecology; Life Sciences, general;
• 出版者：Springer International Publishing
• ISSN：1420-9055
• 卷排序：79

文摘

In forested headwater streams, decomposition of allochthonous organic matter is a fundamental process driven by aquatic microbes and invertebrate shredders. We examined how season and eutrophication affect leaf decomposition and the associated decomposer communities by immersing leaves of a late deciduous species (Quercus robur) in five streams in Portugal along a gradient of eutrophication in autumn and spring. We found hump-shaped relationships between leaf decomposition and total nitrogen and phosphorus in stream water in both seasons. Leaf decomposition and shredder biomass were higher during spring in streams with moderate levels of eutrophication. Fungal sporulation and biomass were stimulated at moderate levels of eutrophication and inhibited at low or high levels of eutrophication. Fungal assemblage composition shifted between seasons and along the gradient of eutrophication. Tricladium chaetocladium increased its contribution to total conidial production in spring, while Dimorphosporafoliicola was dominant in the most eutrophic streams where Articulosporatetracladia was almost absent. Invertebrate shredders were the primary decomposers of leaves in streams with moderate levels of eutrophication, particularly in the warmest season. Although the presence of late deciduous plant species, such as oak, in the riparian corridors may help to mitigate food depletion to freshwater decomposers in spring, our results suggest that moderate eutrophication can accelerate decomposition further reducing litter standing stocks in the warmer seasons.