1. Salinisation (i.e. increased ion concentrations) in fresh waters is a growing threat worldwide that impacts freshwater communities. However, less is known about how increased salt concentrations affect key ecosystem processes such as leaf decomposition.
2. We designed a laboratory experiment to assess the effects of a concentration gradient (1, 3, and 6 g/L) of three different salts (NaCl, CaCl₂ and CH₃CO₂K), on leaf litter decomposition mediated by microbial decomposers and the larvae of a cased caddis fly (Schizopelex festiva, Trichoptera). Leaf discs of Quercus robur inoculated with microbial decomposers (a mixture of 5 fungal species) were incubated in microcosms under every possible salt × concentration combination and without salt addition (control), with a single individual of the cased caddis fly. Half of the leaf disks were not available for consumption by the trichopteran and represent a microbial only treatment when leaf mass loss was measured.
3. Leaf decomposition driven by microbial decomposers was not affected by salinity despite the fact that all salt treatments depressed fungal biomass and microbial respiration compared to the control. However, the caddis flies were strongly affected by the high salt concentrations and consumed less leaf material at 6 g/L salt concentrations compared to control microcosms. The feeding activity of the trichopteran further depended on the salt type: CaCl₂ had the most deleterious effects.
4. Salinisation of fresh waters depresses leaf litter decomposition, mainly through deleterious effects on detritivores, the magnitude of the response being dependent on the ionic composition. Our results reiterate the need to reduce terrestrial run‐off of salts into fresh waters because salinisation (especially increased levels of CaCl₂) affects invertebrates and the key ecosystem processes they drive.

中文翻译：

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盐渍化对淡水中叶片凋落物分解的影响：盐的离子成分是否存在？

1. 淡水中的盐碱化（即增加的离子浓度）是全球范围内影响淡水社区的日益严重的威胁。但是，人们对盐浓度增加如何影响关键的生态系统过程（如叶片分解）知之甚少。
2. 我们设计了一个实验室实验，以评估三种不同盐（NaCl，CaCl ₂和CH ₃ CO ₂ K）的浓度梯度（1、3和6 g / L）对微生物分解剂和微生物介导的凋落物分解的影响。盒装cad蝇（Schizopelex festiva，Trichoptera）的幼虫。将接种了微生物分解剂（5种真菌物种的混合物）的栎栎的圆盘在显微镜下以每种可能的盐x浓度组合且不加盐（对照）的条件下孵育，并由一个单独的盒装球果蝇进行培养。鳞翅目不能食用一半的叶盘，仅代表微生物 测量叶片质量损失时的处理。
3. 尽管与对照相比，所有盐处理均抑制了真菌生物量和微生物呼吸，但由微生物分解剂驱动的叶片分解不受盐度的影响。然而，与对照微观世界相比，高盐浓度强烈影响了果蝇，并且在6 g / L盐浓度下消耗的叶片材料更少。Trichopteran的摄食活性进一步取决于盐的类型：CaCl ₂具有最有害的作用。
4. 淡水的盐渍化主要通过对有害物的有害作用来抑制叶片凋落物的分解，响应的幅度取决于离子组成。我们的结果重申了减少盐分流向淡水的需求，因为盐碱化（特别是CaCl ₂含量的增加）会影响无脊椎动物及其驱动的关键生态系统过程。