Litter decomposition is a vital link between material circulation and energy flow in forest ecosystems and is intensely affected by global change factors, such as increased nitrogen (N) deposition and altered precipitation regimes. As essential nutrients, calcium (Ca), magnesium (Mg), and manganese (Mn) play crucial roles in plant energy metabolism, photosynthesis, and membrane transport of plants, and the major source of these nutrients is litter decomposition. However, the dynamics of Ca, Mg, and Mn during decomposition have been largely ignored. Thus, to better understand Ca, Mg, and Mn dynamics during leaf litter decomposition in the scenario of increasing N deposition and decreasing precipitation, we carried out a two-year field litterbag experiment in a natural evergreen broad-leaved forest in the central area of the rainy area of Western China. Two levels of N deposition (ambient N deposition and 150 kg·N·ha⁻¹·y⁻¹) and precipitation reduction (no throughfall reduction and 10% throughfall reduction) were set, i.e., control (Ctr: without nitrogen deposition or throughfall reduction), N deposition (N, 150 kg·N·ha⁻¹·y⁻¹), throughfall reduction (T, 10% throughfall reduction), and N deposition and throughfall reduction (NT, 150 kg·N·ha⁻¹·y⁻¹ and 10% throughfall reduction). We found that leaf litter Ca concentration increased in the early decomposition stage and then decreased, while Mg and Mn concentrations generally decreased during the whole period of decomposition. The amount of Ca showed an accumulation pattern, while Mg and Mn generally showed a release pattern. N deposition and throughfall reduction affected the Ca, Mg, and Mn dynamics, varying with different decomposition stages; i.e., N deposition significantly affected the concentration and amount of Ca, regardless of the decomposition stages, while throughfall reduction significantly affected the Ca concentration in the whole and early decomposition stages. N deposition significantly affected the concentration and amount of Mg in the whole and early decomposition stages, while throughfall reduction had no significant effects. Throughfall reduction significantly affected the concentration and amount of Mn in the whole and late decomposition stages, while N deposition had no significant effects. Ca concentration generally showed a significant positive linear relationship with mass loss in the early decomposition stage; Mg concentration showed a significant positive linear relationship with mass loss in the Ctr and N treatments in the early and late decomposition stages; Mn generally showed a significant negative linear relationship with mass loss, regardless of the decomposition stage. Overall, the results suggest that Ca accumulation is more likely affected by N deposition, while Mg and Mn releases are more likely affected by N deposition combined with throughfall reduction, particularly in the early decomposition stage.

Stand-density management and fertilization practices are the main two factors affecting bamboo-shoot yield. However, the appropriate density and fertilization rates are still unclear for improving the bamboo-shoot yield and its economic benefits, especially for a high economic value bamboo-shoot forest. To fill this gap, we conducted a two-year split-plot design experiment in a Chimonobambusa pachystachys shoot forest. The main plots were assigned to five density rates, 40,000, 50,000, 60,000, 70,000, and 100,000 culms ha⁻¹, and the subplots were assigned to four fertilization rates (nitrogen:phosphorus:potassium = 23:3:15): 0, 820, 1640, and 2460 kg ha⁻¹ a⁻¹. Results showed that the bamboo-shoot yield increased first and then decreased with stand density, while it increased with fertilization rates. Density management and fertilization regulate bamboo-shoot yield by changing the soil’s Olsen P, available nitrogen, organic matter, and available potassium contents. The maximum bamboo-shoot yield was 9315.92 kg ha⁻¹, which appeared in the density of 60,000 culms ha⁻¹ and the fertilization of 2460 kg ha⁻¹ a⁻¹. However, the maximum bamboo-shoot net profit was 135,242.63 CNY ha⁻¹, which appeared at the density of 60,000 culms ha⁻¹ and the fertilization of 1640 kg ha⁻¹ a⁻¹. The economic-benefit analysis shows that density management achieves a net-profit growth comparable to fertilizer application at a much lower cost. The study results provide a basis for the scientific management of C. pachystachys shoot forests and bamboo farmers to improve their income.

Soil mesofauna plays an important role in decomposing organic matter, recycling nutrients, and increasing nutrient availability. The effects of nitrogen (N) deposition and reduced precipitation on the litter-dwelling mesofaunal community and how this process affects litter decomposition remain poorly understood. Herein, a two-year simulated N deposition and throughfall reduction experiment was carried out in a natural evergreen broad-leaved subtropical forest to examine the effects of N deposition and reduced precipitation on soil mesofauna during litter decomposition. Four treatments were established: control (CK), N deposition (N), reduced precipitation (RP), and combined N deposition and reduced precipitation (N + RP). We collected and identified 19,782 individuals of mesofauna in litterbags during the whole experiment. Mites (Prostigmata, Mesostigmata, and Oribatida) and Collembola comprised almost 90% of the total number of individuals collected and dominated the soil mesofauna in our study. Our results revealed the negative effects of N deposition on the density of Oribatida mites and Collembola and the total density of soil mesofauna. Reduced precipitation significantly increased the density of Collembola and Oribatida mites and the total density of mesofauna and marginally significantly increased the density of Mesostigmata mites but decreased the diversity of mesofauna. The interaction effects of N deposition and reduced precipitation significantly affected the density of Prostigmata mites, Oribatida mites, Collembola, and the diversity of mesofauna. N deposition combined with reduced precipitation significantly inhibited litter decomposition, whereas no significant interaction effects were observed. Furthermore, correlation analysis indicated that litter mass loss was significantly positively correlated with the density of Prostigmata, Mesostigmata, and Oribatida, as well as the diversity of mesofauna. Overall, during the two-year decomposition process, our results suggest that N deposition and reduced precipitation interactively affected mesofaunal diversity and that N deposition adversely affected the mesofaunal community, while reduced precipitation increased the density of some groups but decreased mesofaunal diversity, consequently cascading on the decomposition of leaf litter.

Leaf functional traits are important indicators that reveal plant adaptation and response to environmental changes. Characteristics and adaptive strategies of leaf functional traits of staple bamboo species (SBSs) for the giant panda (Ailuropoda melanoleuca) remain unclear, which limits conservation management of the giant panda and its habitat. Here, this study investigated 10 SBSs in 15 nature reserves across 36 counties, measured eight leaf functional traits, analyzed trait characteristics, variation, and drivers of variation, and examined trait-based strategies and strategy–environmental constraint relationships. Our results indicate that: coefficients of variation in leaf functional traits spanned from 9.58% to 79.16%, and significant differences were found among SBSs for leaf functional traits except chlorophyll concentration. The linear mixed-effects models revealed that the taxonomic factors explained 20.16 to 77.94% of variation, and environmental factors explained 17.03 to 29.12%. Leaf functional traits exhibited distinct environmental associations, primarily driven by geographic location, topography, and soil phosphorus availability. Hierarchical clustering and principal component analysis revealed 10 SBS clustered into two groups, corresponding to conservative and acquisitive resource-use strategies. Canonical correspondence analysis revealed that SBSs with conservative strategies were distributed in warm and moist habitats, and SBSs with acquisition strategies were distributed in habitats with high solar radiation. Our results reveal the key trait characteristics of SBSs and the strategy-environmental constraint model based on traits, which can provide scientific basis for the ecological management practice of SBSs.