This paper conducts a scientific assessment of aesthetic quality to provide intuitive and scientific planning strategies for national park construction. Focusing on Qianjiangyuan National Park, the study used the scenic beauty evaluation (SBE) method to subjectively assess landscape photos from 16 sample sites. Objective eye movement indicators describing visual behavior were also analyzed. A national park landscape visual quality assessment model was derived through multiple linear regressions correlating subjective evaluations with objective indicators. Spatial technologies like ArcGIS were used to analyze the visual quality and its spatial distribution. Key findings include (1) subjective evaluations showed higher SBE scores for wetland landscapes, followed by recreational, village, and forest landscapes, (2) eye movement behavior varied across landscape types, with the forest landscape having the shortest first fixation time and the lowest saccade frequency, while recreational landscapes had the lowest average saccade speed, (3) strong correlations were found between SBE and indicators such as average fixation time and saccade frequency, with fixation duration ratio being the leading factor influencing visual aesthetic quality, and (4) visual aesthetic quality was highest in the north and south areas of the park, with significant differences between sample sites in these regions compared to the central area. Among different functional zones, the ecological protection area had the highest quality, while the Suzhuang management area excelled in aesthetic quality compared to the Hetian management area.

The scientific evaluation of the ecosystem service value (ESV) of national parks and understanding the trade-offs and synergies between different ecosystem services (ESs) are crucial for advancing the establishment of China’s national park system. However, current research on ESs in national parks is mostly focused on the value assessment of certain types of services. The analysis of their impacts under specific socioeconomic conditions remains very limited, and research on the trade-offs and synergies between different ESs is scant. This study focuses on China’s Qianjiangyuan National Park (QNP) pilot area. To evaluate its ESV at both the temporal and spatial scales, models and tools including value equivalent factors, partial least squares regression, sensitivity analysis, spatial autocorrelation, and trade-off/synergy assessment are utilized. Moreover, the influencing factors of ESV evolution under specific socioeconomic conditions are analyzed, and the trade-off/synergy relationships between ESVs are identified. The results indicate the following. (1) The total ESVs in 1990, 2000, 2010, 2015, and 2020 were respectively CNY 170.63 × 107, 169.65 × 107, 171.89 × 107, 171.95 × 107, and 172.11 × 107. Forest land was the main contributor to ESV, and the type of ES with the highest contribution rate was regulating services. (2) Positive spatial autocorrelations were found for ESVs in the national park pilot area, indicating a clustered distribution pattern. High-value clusters were identified in Suzhuang Town and Qixi Town. (3) The added value of secondary industries, the added value of primary industries, and the added value of agriculture, forestry, animal husbandry, and fishery were found to be the most important factors affecting ESV changes in the pilot area. The tea yield had no effect on the evolution of ESV. (4) In the pilot area, synergies between ESs were more stable than trade-offs, with synergies accounting for 66.67%. Trade-offs primarily existed between food production services and other services. Compared with previous investigations, this research represents a long-term, multi-scale, and comprehensive dynamic study on the only national park system pilot area in eastern China. Moreover, it presents a set of socioeconomic evaluation indicators suitable for creating national parks in economically developed, densely populated areas with complex land ownership complex. The research results enhance the comparability, generalizability, and replicability of national park ESV evaluation methods and outcomes, and provide a valuable reference for conducting ES research in other types of nature reserves.

Petroleum hydrocarbon contamination poses a persistent threat to soil quality and ecosystem functioning, while conventional remediation approaches are often costly and difficult to sustain over the long term. This study evaluated garden waste biochar as a sustainable amendment for the remediation of petroleum-contaminated soil and investigated its effects on TPH removal, soil physicochemical properties, and bacterial community changes. Biochar produced from garden waste at 600 °C was applied at 1% and 2% (w/w) to soil containing approximately 20,000 mg·kg⁻¹ TPH, and changes were monitored over 360 days. High-throughput 16S rRNA gene sequencing and redundancy analysis were combined with measurements of soil properties and TPH concentrations. Compared with the petroleum-contaminated control, biochar amendment substantially enhanced TPH removal, with removal efficiencies increasing from 24.44% to 44.26% and 52.93% under 1% and 2% biochar treatments, respectively. After 360 days, TPH concentrations decreased to 10,831.68 and 9102.07 mg·kg⁻¹ in the 1% and 2% biochar treatments, respectively. Biochar also significantly altered bacterial richness and community composition, with significant changes in the Ace, Chao1, and Sobs indices and shifts in dominant bacterial phyla. Soil nutrient availability and bacterial community structure were closely associated with environmental changes during remediation. Overall, garden waste biochar shows potential as a sustainable strategy that simultaneously promotes biomass waste valorization and petroleum-contaminated soil remediation.