The water level fluctuation zone (WLFZ) has experienced a novel hydrological regime due to the anti-seasonal operation of China’s Three Gorges Reservoir. Overall, hydrological change can significantly influence the riparian environment and shift the riparian vegetation. Although numerous studies have investigated the short-term responses of riparian plants to water level fluctuation in this zone, few have addressed long-term effects. In this study, four permanent plots in the WLFZ of the canyon landform area were chosen to evaluate the long-term responses of riparian plants to water level fluctuation from 2008 to 2015 and to screen candidate plants for ecological restoration. We recorded 146 species in 2008, 110 species in 2009, 68 species in 2012 and 69 species in 2015, indicating a conspicuous loss in riparian plants. Most of the remnant plants were annual and perennial herbs. Of the native species present in 2008, 82, 22 and 8 had disappeared in 2009, 2012 and 2015, respectively. Simultaneously, 45, 15 and 11 non-native species were first found, respectively. Additionally, over half of the native and the non-native species were not found after being subjected to a water level fluctuation. From 2008 to 2015, only 27 native species always presented; however, not all of them were chosen as candidates for ecological restoration because of their decreased importance values. In contrast, the importance value of Cynodon dactylon increased over time, suggesting its high tolerance to long-term winter flooding. We concluded that riparian plants’ composition of the canyon landform area dramatically declined after long-term water level fluctuation and their presence was determined by the novel hydrological condition. Our results also suggested that Cynodon dactylon or its combination with other species (i.e. Digitaria chrysoblephara, Setaria glauca, Setaria viridis) is a better candidate for ecological restoration in the WLFZ.

Prediction of forest carbon sink in the future is important for understanding mechanisms concerning the increase in carbon sinks and emission reduction, and for realizing the climate goals of the Paris Agreement and global carbon neutrality. Based on stand volume data of permanent monitoring plots of the successive national forest inventories from 2004 to 2018, and combined with multiple variables, such as climatic factors, soil properties, stand attributes, and topographic features, the random forest algorithm was used to predict the stand volume growth-loss and then calculated the forest biomass and its carbon sink potential between 2015 to 2060 in the Yangtze River Economic Belt of China. From 2015 to 2060, the predicted forest biomass carbon storage and density increased from 3053.27 to 6721.61 Tg C and from 33.75 to 66.12 Mg C hm⁻², respectively. The predicted forest biomass carbon sink decreased from 90.58 to 73.98 Tg C yr⁻¹, and the average forest biomass carbon storage and sink were ranked in descending order: Yunnan, Sichuan, Jiangxi, Hunan, Guizhou, Hubei, Zhejiang, Chongqing, Anhui, Jiangsu, and Shanghai. The forest biomass carbon storage in the Yangtze River Economic Belt will increase by 3.67 Pg C from 2015 to 2060. The proportion of forest C sinks on the regional scale to C emissions on the national scale will increase from 2.9% in 2021–2030 to 4.3% in 2041–2050. These results indicate higher forest carbon sequestration efficiency in the Yangtze River Economic Belt in the future. Our results also suggest that improved forest management in the upper and middle reaches of the Yangtze River will help to enhance forest carbon sink in the future.

Investigating the mechanisms by which plants adapt to low phosphorus content in ecosystems is crucial for nutrient dynamics division. Our study investigated the growth adaptation strategies of Pinus massoniana seedlings to low phosphorus conditions, including nutrient and non-structural carbohydrate (NSC) allocation, nutrient stoichiometry, and changes in nutrient resorption efficiency along a fact-based gradient. Our results showed that the total biomass and aboveground biomass proportion increased with substrate phosphorus content, reaching maximum biomass in the one-time phosphorus treatment. The nutrient concentration of components remained relatively stable, with the allocating preference to roots and needles under low phosphorus conditions. NSC was allocated as starch in fine roots and as soluble sugar in needles. Seedlings did not show signs of phosphorus limitation, even in the non-phosphorus group. The nitrogen resorption efficiency to phosphorus resorption efficiency ratio (NRE: PRE) of needles significantly varied between the high and low phosphorus treatments. In response to phosphorus deficiency, seedlings demonstrated homeostatic adjustments to maintain the relative stability of nutrient concentration. Fine roots and needles were prioritized to ensure nutrient uptake and photosynthetic product production. Additionally, it was necessary to differentiate the indicative function of nitrogen/phosphorus for various species and components, and NRE: PRE potentially provides a sensitive indicator of nutrient limitation status.