应用生态学报最新文献

Exploring land use changes and their terrain gradient effects can provide a scientific basis for the rational planning and sustainable utilization of land resources. With the Red River Basin in Yunnan Province as the research area, we used land use data of 2015 and 2020, crop data from 2017 to 2020, digital elevation model (DEM) data, distribution index and terrain position index to investigate land use and crop cultivation changes as well as their terrain gradient effects, and further conducted functional zoning. Our results showed that forests dominated the basin, accounting for more than 62.8% of the total area. From 2015 to 2020, the areas of water and built-up land increased by 118.55 km² and 69.68 km², respectively, while other land types decreased. Between 2017 and 2020, maize had the largest planting area and showed an increasing trend, expanding by 270.30 km² in total, the planting areas of single cropping rice and sugarcane fluctuated, whereas rapeseed planting decreased. Cultivated land, built-up land, and water bodies were concentrated at low terrain positions (level of terrain position index was 1-3), whereas forests were concentrated at high terrain positions (level of terrain position index was 8-10), grasslands occurred predominantly at mid-to-low positions (level of terrain position index was 1-5). Single-cropping rice tended to expand toward higher terrain positions. Maize was distributed relatively evenly at mid positions. Sugarcane and rapeseed were concentrated at mid and low terrain positions, respectively. The basin could be divided into four functional zones: urban-agricultural coordinated development zone, transitional agro-pastoral composite zone, ecological forestry and steep-slope management zone, and natural ecological conservation zone. The findings would provide a scientific basis for regional land use planning and agricultural structural adjustment.

The rapid and accurate monitoring of soil organic carbon (SOC) is of great significance for evaluating the quality of reclaimed soils in mining areas. With reclaimed soils from the Xinglongzhuang Coal Mine as the object, we constructed five types of inversion variables based on drone multispectral imagery and sample SOC content: band mathematical transformation groups, traditional spectral index groups, improved spectral index groups, full-variable groups, and groups selected by the improved greedy algorithm (IGA). We further built SOC inversion models with six machine learning algorithms, AdaBoost, backpropagation neural network (BPNN), CatBoost, LightGBM, random forest (RF), and XGBoost. The results showed that: 1) When the improved spectral index group was used as the variable, the accuracy of inversion model was higher than that of the traditional spectral index group. 2) When the IGA-selected variable group was used, the accuracy and stability of the model significantly improved. 3) The LightGBM model using the IGA-selected variable group was the optimal SOC inversion model for reclaimed soils, with a modeling set coefficient of determination (R²) of 0.825, root mean square error (RMSE) of 0.914, a validation set R² of 0.793, and RMSE of 0.945. 4) The inverted SOC content ranged from 7.75 to 13.60 g·kg^-1, with an average of 10.48 g·kg^-1, which was consistent with the sample SOC measurements. These fin-dings could provide technical support for the planning and implementation of land reclamation in mining areas.

Enhancing the resilience of forest ecosystems is critical for promoting sustainable forestry and regional collaborative governance. To optimize sustainable forestry strategies and strengthen ecological civilization construction, we constructed an evaluation index system for measuring the resilience of forest ecosystems in 31 provinces of China from 2004 to 2021 based on the pressure-state-response (PSR) framework, using the entropy method to determine indicator weights. We established a spatial association network through a modified gravity model and applied social network analysis along with quadratic assignment procedure (QAP) to analyze the structural characteristics and driving factors of the network. The results showed that the overall resilience of China's forest ecosystems increased from 0.13 in 2004 to 0.18 in 2021. There were regional variations across the eastern, central, western, and northeastern regions. The overall network connectivity of China's forest ecosystem resilience required improvement, with individual network structures exhibiting pronounced "core-periphery" characteristics. Henan, Hubei, and Hunan occupied core positions, while Jilin, Heilongjiang, and Tianjin were situated at peripheral locations. Forest ecosystem resilience spatial association network could be divided into four major blocks, characterized by relatively strong internal connections within each block and relatively weak interactions between blocks. Differences in regional total forestry output value, geographical adjacency relationship, forestry ecological construction investment, and forest coverage exerted a strong positive influence on the establishment of the spatial association network, while differences in the proportion of forestry tertiary industry in GDP exerted a weak negative influence. Our results suggested that we should rely on the location advantages of core provinces and regions, strengthen cross-regional cooperation and resource sharing, and give play to the spatial radiation effect of core regions. Meanwhile, we should optimize the spatial allocation of forestry resource elements and develop targeted implementation plans.

Meconopsis comprises rare alpine plants with high ornamental value. Due to global warming and human activities, their habitats have been destroyed. To provide data support for the dynamic monitoring of Meconopsis species and ex situ conservation, and to offer reference for species classification within the genus Meconopsis, we focused on two flagship species of typical alpine scree habitats, M. horridula and M. racemosa. Based on the geographic distribution data, we used the MaxEnt model 3.4.4 to simulate the suitable habitat areas of both species for the current (1970-2000) and future (2041-2060, 2061-2080) periods, and used ArcGIS 10.8 to analyze the dominant factors affecting their habitat suitability and the dynamics of suitable areas under future climate warming. The area under the receiver operating characteristic curve values for both Meconopsis species were greater than 0.9, indicating that the model predictions were accurate. Altitude, isothermality, temperature seasonality, and human footprint were the main variables affecting the suitable distribution of M. horridula and M. racemosa. Currently, the total suitable area for M. horridula and M. racemosa were 2.60 million and 1.62 million km², respectively, with an overlap of 1.58 million km², indicating that the suitable ranges highly coincided. Currently, the suitable areas of both Meconopsis species were distributed in Yunnan, Sichuan, Gansu, Qinghai, Tibet, and Xinjiang, and under the influence of climate warming, there would be a potential migration toward the northwest in the future. The main suitability variables of M. horridula and M. racemosa were consistent, with total suitable ranges being highly coincided.

To breed new drought-resistant poplar varieties suitable for the Three-North Region, we used Populus alba var. pyramidalis (PaP) (with strong drought resistance but weak insect resistance) and P. deltoids 'Shalin-yang' (PdS) (with weak drought resistance but strong insect resistance) as hybrid parents. We cultivated their hybrid progenies P. 'Shaxin 2' (PdSPaP_2), P. 'Shaxin 3' (PdSPaP_3), and P. 'Shaxin 4-1' (PdSPaP_4) as research objects, with the parents as controls in the solar greenhouse (day temperature: 25-28 ℃, night temperature: 18-20 ℃, relative humidity: 60%-70%, photosynthetically active radiation: 800-1000 μmol·m^-2·s^-1). After a 21-day artificial drought stress, the changes in anatomical structure, physiological and biochemical characteristics, and photosynthetic parameters of each variety at the seedling stage were compared. The results showed that the epidermal thickness of young stems of PdSPaP_4 was not significantly different from that of PaP, but significantly higher than that of other varieties. After 21 days of drought, PdSPaP_2 died due to rapid water loss and severe damage in the membrane system, while the other varieties, though showing wilting, remained alive. Leaf relative water content (RWC) of PaP decreased from 89.4% to 50.4%, and that of PdSPaP_4 decreased from 91.6% to 42.5%. The two varieties had the lowest increase rates in relative electrical conductivity (REC), indicating the least membrane damage. PaP and PdSPaP_4 initiated stomatal closure on the 7th day of drought, and the decrease rate of their photosynthetic rate on the 21st day was significantly lower than that of PdS. In conclusion, drought resistance of the P. 'Shaxin' series was ranked as: PdSPaP_4 > PdSPaP_3 > PdSPaP_2. PdSPaP_4 had drought resistance close to that of its male parent (PaP) and thus has the potential to be used as the main poplar variety for shelterbelt construction in the arid areas of the Three-North Region.

Litter decomposition is crucial for restoration of burned areas in the alpine forests of northwestern Sichuan. With the indigenous tree species in the alpine region of Ganzi, Quercus semicarpifolia and Abies fabri, as the research objects, we set up five treatments, including single Q. semicarpifolia litter (Q), single A. fabri litter (A), and 3 mixed treatments (the two were mixed at a ratio of 3:1, 1:1, and 1:3, namely QA_3:1, QA_1:1, and QA_1:3). All the litters were incubated in a 600-day field decomposition experiment in forest burned areas. We explored the decomposition characteristics of recalcitrant substances (lignin, cellulose, and total phenols) during decomposition. The results showed that the lignin degradation rate of mixed litter was generally lower than that of single Q. semicarpifolia (except for QA_3:1 decomposed for 600 d), but higher than that of single A. fabri (except for 120 d of decomposition). The degradation rates of cellulose and total phenols in mixed litter were generally higher than those in the two single tree species (except for the cellulose degradation in QA_3:1 at 240 d, and the total phenol degradation in QA_1:1 and QA_1:3 at 120 and 240 d, respectively). During the decomposition process, the observed degradation rates of lignin, cellulose and total phenols were higher than the predicted values in 58.3%, 77.8% and 86.1% of the mixed leaf litter samples, respectively, exhibiting a synergistic trend. For the QA_1:3 mixture, both cellulose and total phenol degradation rates exhibited significant synergistic effects throughout the 600-day decomposition. Lignin degradation rate at 240 d of decomposition was significantly correlated with initial lignin and total cellulose content, while it was significantly correlated with initial total phenolic content, total carbon, and total nitrogen content at 480 d of decomposition. Our results showed that litter mixture with a 1:3 ratio of Q. semicarpifolia and A. fabri facilitated the decomposition of the recalcitrant substances, thereby promoting soil organic carbon accumulation.

Soil acidification in agricultural lands has become an increasingly prominent issue, posing a serious threat to soil health. Alkaline amendments is a feasible approach to mitigate acidification, yet their effects on soil microbial properties remain unclear. We conducted a meta-analysis with literature published during 1980 to 2024, to examine the impacts of alkaline materials (lime and biochar) on soil pH, microbial biomass carbon, and microbial diversity in acidified soils. Results showed that both lime and biochar significantly increased soil pH (by 9.1% and 4.4%, respectively), with greater improvements at higher application rates. The strongest effects occurred within 0.25 years after application (19.7% for lime and 9.4% for biochar). Alkaline amendments were the most effective under high temperature (>16 ℃), high rainfall (>1200 mm), and strongly acidic soils (pH≤4.5). Lime and biochar increased microbial biomass carbon by 81.6% and 18.4%, respectively, with the greatest effects observed within 1-2 years. Higher lime application rates (3-6 t·hm^-2·a^-1) produced the strongest improvements, whereas biochar was more effective at lower rates (≤1.5 t·hm^-2·a^-1). Overall, microbial diversity increased by 2.5% following amendment application. Biochar enhanced microbial diversity most strongly within 0.25-0.5 years (14.1%), while lime required more than two years to achieve significant improvement (8.5%). Lime was more effective in low-temperature, low-rainfall regions (up to 6.8%), whereas biochar was better suited to high-temperature, high-rainfall regions (5.5%). Biochar influenced microbial properties indirectly by regulating soil pH, with microbial biomass and diversity showing significant positive correlations with soil pH. In contrast, lime-induced changes in microbial properties were strongly affected by application rate, climatic condition, and initial soil pH. This study clarified the acid-neutralizing effects and soil microbial regulation mechanisms of different alkaline amendments, providing a foundation for further exploration of the coupled physical, chemical, and biological restoration processes in the amelioration of acidified soils.

Quantitative assessment of the correlation between natural capital utilization and high-quality development in Henan Province is of great significance for ecological protection and high-quality development in the Yellow River Basin. We constructed high-quality development index (HQD) and used it to quantify the development of each city in Henan Province based on the new development philosophy. We further employed the extended three-dimensional ecological footprint model to evaluate natural capital utilization. Spatiotemporal evolution of HQD and natural capital utilization during 2005-2023 was analyzed, and their correlation was further explored using the decoupling index and threshold regression model. Results showed that there was significant heterogeneity in HQD and each dimension scores across all the cities in Henan. Overall, HQD in western Henan was higher than that in eastern Henan, presenting a multi-layered decreasing pattern centered on Zhengzhou. Zhengzhou had the highest annual average HQD of 0.55, while the HQD value of Jiyuan was the lowest (0.22). All the 18 cities had the highest scores in coordination dimension and the lowest in innovation dimension. The maximum ecological footprint size (EF_size) was 2.64×10⁶ hm² in Zhoukou, and Jiyuan recorded the minimum of 1.80×10⁵ hm². Cropland, grassland, and construction land contributed substantially to EF_size, with the proportion of contribution from construction land increasing over time. Ecological footprint depth (EF_depth) of Xuchang reached a maximum of 8.68 while the minimum was 4.12 in Xinyang. Cropland and grassland accounted for relatively high proportions of EF_depth, while construction land made the smallest contribution. The relationship between HQD and EF_size in each city exhibited a significant inverted 'U'-shaped curve, with the inflection point of multi-year average HQD at 0.43. HQD and EF_depth in the three cities of Luohe, Sanmenxia, and Xinyang showed a weak decoupling relationship, while the remaining 15 cities showed a strong decoupling during 2005-2023. The first-order lag term of HQD exerted a significant positive impact on current HQD. Both EF_size and EF_depth played a positive role in promoting HQD improvement, with a nonlinear trend of weakening from a strong initial state.

Stand density is a key factor influencing forest structure and function. Its regulatory effects on soil structure and nutrient cycling are directly related to forest productivity and ecosystem functions. To investigate the effects of stand density of Robinia pseudoacacia plantation on soil stability and nutrient content, we selected stands with five density gradients (800-1100, 1100-1400, 1400-1700, 1700-2000, 2000-2300 plants·hm^-2) in the Cai-jiachuan watershed of Ji County, Shanxi Province. The composition of soil aggregates and nutrient characteristics in the topsoil (0-10 cm) and subsurface layers (10-20 cm) were determined. The results showed that soil aggregate stability decreased and nutrient content declined as stand density increased from 800-1100 to 2000-2300 plants·hm^-2. In the topsoil layer, the proportion of macroaggregates, mean weight diameter (MWD), and geometry mean diameter (GMD) decreased by 2.3%, 33.0%, and 19.4%, respectively. In the subsurface layer, they decreased by 10.9%, 25.3%, and 24.2%, respectively. The fractal dimension (D) showed no change. Total nitrogen (TN) and organic carbon (SOC) contents generally decreased with increasing stand density, but no significant trend was observed in the total phosphorus (TP) content. The aggregates with 0.25-1 mm size fraction had the highest contents of TN, TP, and SOC. The MWD, GMD, TN, TP, and SOC content in the topsoil were significantly higher than that in the subsurface soil. The interaction between stand density and soil layer had a significant negative effect on GMD, and a highly significant positive effect on D, collectively explaining 60.1% of the variation in soil aggregate stability. TN content was significantly positively correlated with GMD and negatively correlated with D. The stand density of 800-1100 plants·hm^-2 could effectively maintain soil structural stability and carbon and nitrogen sequestration.