应用生态学报最新文献

The urban heat island (UHI) effect and urban air pollution (UPI) have received concerns from the government and the public. Based on the data of temperature, PM_2.5 concentration and downward long-wave radiation (DLR) from 9 meteorological stations, 10 environmental monitoring stations and 1 radiation monitoring station in Shenyang for one whole year from December 1, 2018 to November 30, 2019, we divided the meteorological stations and environmental monitoring stations into urban and suburb stations according to their locations and the distance between stations. We used an urban-suburb temperature difference method calculated the seasonal, monthly, diurnal intensities of the UHI and UPI in Shenyang urban compared with the southwest and northeast suburbs, and analyzed the relationships among UHI, UPI and DLR. Results showed that the seasonal, monthly, and hourly temperature in Shenyang showed an order of urban>southwest suburb>northeast suburb. Compared to basing on the southwest suburb, the urban heat island intensity in Shenyang was much higher when based on the northeast suburb. The maximum seasonal, monthly, and daily heat island intensities occurred in winter (urban were 2.82 ℃ and 1.75 ℃ higher than the northeast and southwest suburbs, respectively), January (urban were 3.04 ℃ and 1.87 ℃ higher than the northeast and southwest suburbs, respectively), and at 00:00 (urban were 3.09 ℃ higher than the northeast suburb) or 01:00 (urban were 2.20 ℃ higher than the southwest suburb). The PM_2.5 concentrations in Shenyang were lowest in the northeast suburb across seasons, months, and days. During summer, from June to August and between 11:00 and 17:00, urban PM_2.5 concentrations were higher than those in the southwest suburb. In other seasons and time periods, the southwest suburb exceeded urban area. Urban heat island intensity showed a significant negative correlation with pollution island intensity. Downward long-wave radiation was significantly correlated with urban pollution island intensity both day and night, but only with urban heat island intensity during nighttime. Downward long-wave radiation affected urban heat island intensity and pollution island intensity through temperature and PM_2.5.

Albic soil is a typical low yield soil with barrier layer in Northeast China. Due to the dense structure of the barrier layer and the difficulties in water and gas transmission, it restricts crop growth and yield formation. We set up a manipulative experiment, with no amendment (CK) as the control to explore the effects of three amendments: composite amendment (modified bentonite+modified humic acid+calcium oxide, GL), modified bentonite (PR), and modified humic acid (HA) on the physical structure and microbial diversity of albic layer. The results showed that the improvement agent significantly reduced soil bulk density of the albic layer by 3.6% to 5.4%, increased the porosity by 4.7% to 7.0%, and increased the stability of aggregates. Among them, GL treatment enhanced the connectivity of pores by loosening soil particles. PR treatment could improve soil aeration in the short term, but with insufficient stability of aggregate structure. HA treatment enhanced aggregate stability through colloid filling, but had limited improving effect on pore connectivity. Different amendments changed soil microbial community composition in the albic layer. GL treatment significantly increased bacterial diversity, with a 12.9% increase in richness, with the community under which being dominated by Proteobacteria, Bacteroidetes, and Actinobacteria. The PR treatment increased bacterial richness by 17.4%, with the community under which being dominated by Actinobacteria, Proteobacteria, and Ascomycota. HA treatment significantly increased fungal species richness, with a 41.0% increase in Chao1 index. The dominant fungal communities were Ascomycota, Basidiomycota, and Zygomycota. Soil porosity was positively correlated with fungal abundance (r=0.62), and bulk density was positively correlated with actinomycete abundance (r=0.58). In summary, GL treatment had a good physical and biological synergistic effect and was more suitable for loosening the albic layer, improving soil permeability. PR treatment could improve the aeration and microbial activity of the albic layer in the short term, but its promotion effect on the stabi-lity of aggregate structure was limited. Long-term application may facilitate soil structure loosening. HA treatment was suitable for soils with high water retention requirements and the need to enhance aggregate stability.

Mixing the albic horizon with the illuvium horizon can break the poor soil structure of albic soil, while straw input is an effective way to enhance soil nutrient content. We conducted an incubation experiment to analyze the changes in soil liquid limit, plasticity index, mechanical composition, distribution of stable aggregates, and soil organic carbon content under different mixing ratios of the albic horizon and illuvium horizon (1:0, 2:1, 1:1, and 1:2), along with the addition of 1% corn straw. We further verified the impacts with a soybean field experiment. The results showed that with the increasing proportion of illuvium horizon soil, the liquid limit of the soil increased, and the plasticity index increased from 16.0% to 23.0%, 27.0%, and 31.0%, respectively. The suitability of albic soil for cultivation was enhanced. The stability indicators of soil aggregates, such as clay content, percentage of aggregates larger than 0.25 mm (R_>0.25), average weight diameter (MWD), geometric mean diameter (GWD), increased, with MWD and GWD increasing by 42.9%, 44.9%, 46.9% and 27.7%, 27.7%, 29.8%, respectively. At the same mixing ratio, straw addition increased soil R_>0.25 and enhanced aggregate stability. Soil mixing and straw addition, as well as their interaction, had significant effects on soil R_>0.25, MWD, and GMD. The treatment with soil mixing ratio of 1:1 and straw addition resulted in the highest R_>0.25, reaching 66.6%. Soil mixing reduced soil organic carbon content, while straw addition significantly increased soil total organic carbon and aggregate organic carbon content at various particle sizes. This indicated that the combination of soil layer mixing and straw addition synergistically promoted the formation and stability of soil aggregate structure by increasing soil clay and organic carbon content, thereby improving soil structure and fertility. Field results showed that the application of machinery could achieve approximately 1:1 mixing of albic soil horizon and illuvium horizon. Compared with conventional deep loosening control, the soybean yield increased by 7.2% after the mixing operation and full straw return. This model had significant promotion effect in the improvement of albic soil.

The poor tillage properties in low-yielding albic soil caused by physical structural obstacles are unfavorable for mechanical tillage operations. To address this problem, we conducted indoor simulation experiments with three types of treatments: tillage layer mixing (TLM, where 10%-50% of the albic soil was incorporated into the surface soil), subsoil mixing (SM, where 10%-50% of the illuvial soil was incorporated into the albic soil), and subsoil fertilization (SF, with gradients of 2%-10% organic fertilizer, straw, and biochar addition, respectively). We analyzed the differential regulatory mechanisms of various soil improvement measures on the plasticity (indicated by liquid limit, plastic limit, and plasticity index), swelling-shrinkage behavior (indicated by shrinkage limit), and optimal tillage period (indicated by shrinkage index) of albic soil. Results showed that TLM improved soil homogeneity and plasticity, shortened the optimal tillage period, and degraded tillage characteristics. SM improved the tillage performance of albic soil by increasing clay content and optimizing the sand-clay ratio, which together extended the optimal tillage period. SF, leveraging the synergistic effects of organic matter, specific surface area, maximum hygroscopic water, and organic carbon, demonstrated superior improvement effects on tillage characteristics compared to TLM and SM. Among these, organic fertilizer enhanced soil water retention capacity (plastic limit increased by 37.5%-58.1%), optimizing soil tillage characteristics. Straw exhibited the most significant regulatory effect on soil swelling-shrinkage behavior (shrinkage limit decreased by up to 41.1%), with the optimal effect achieved at a 6% straw addition. Biochar improved soil tillability by optimizing the hierarchical pore structure, where a 10% addition increased the liquid limit and plastic limit by 7.3% and 14.9%, respectively, while reducing the plasticity index by 7.6% and increasing the shrinkage index by 12.6%. These findings indicated that all three soil fertilization materials could improve the tillage characteristics of low-yielding albic soil. This study would provide theoretical support for the remediation of albic soil barriers and the construction of sustainable tillage systems.

Against the backdrop of increasing demands for multiple ecosystem services and intensifying spatial conflicts, constructing an ecological security pattern that ensures both synergy and sustainability has become a central issue in ecological conservation and territorial spatial governance. Available methods for source area identification are mostly based on simple equal-weight overlay or entropy-weighted overlay approaches. Although being practical to some extent, these methods are limited in enhancing the efficiency of multi-service synergies and mitigating trade-offs. To address such limitations, we introduced a scenario-regulated ordered weighted averaging (OWA) model and proposed an optimization approach for ecological security pattern construction oriented toward improving service synergy efficiency. With Yan'an City, a typical ecologically fragile area in Northwest China, as a case study, we tassessed six types of ecosystem services (habitat quality, water yield, soil conservation, carbon storage, cultural aesthetics, and windbreak-sand fixation) under seven risk-preference scenarios to identify optimal synergistic sources. We used Conefor and Linkage Mapper models to construct ecological security pattern under different scenarios, and evaluated their performance in terms of source protection efficiency and corridor network topology by comparing the OWA synergy-based method with the simple overlay and entropy-weighted overlay approaches. Results showed that the OWA synergy-based method consistently demonstrated lower levels of trade-offs among ecosystem services, higher average protection efficiency, and a more favorable network connectivity structure in both 2000 and 2020, outperforming the traditional source overlay methods. The OWA synergy-based approach maintained the highest average protection efficiency in both 2000 and 2020, and performed particularly well in estimating critical ecosystem services of the Loess Plateau, such as windbreak-sand fixation and carbon storage. In terms of network topology, the OWA synergy-based pattern exhibited higher closure and node connection efficiency, indicating stronger stability and fault tolerance. These findings would provide new insights into source identification and spatial optimization under the context of ecosystem service trade-offs, and offer theoretical guidance and practical references for the delineation of ecological restoration priority areas and the planning of territorial ecological restoration.

Understanding the relationship between landscape patterns and water quality in river headwater watersheds is essential for developing sustainable landscape policies to protect water quality in water source areas. With the Qingshan Lake headwater watershed as the research object and based on the data of 25 water sampling sites between 2023 and 2024, we used the partial least squares regression (PLSR), non-parametric change-point analysis and bootstrap methods to quantitatively assess the impacts of landscape patterns on riverine nitrogen concentration during high-flow, normal-flow, and low-flow periods. The results showed that there were significant differences in landscape dominance and fragmentation among different sub-watersheds. High landscape weighted load index (LWLI) values (>0.50) were predominantly observed in low-altitude, gently sloping areas were characterized by extensive "source" landscapes, whereas low LWLI value (<0.10) were mainly distributed in mid-altitude regions dominated by forests. The optimal PLSR model accounted for 60.6%, 69.7%, and 78.3% of the variance in total nitrogen (TN) concentrations during the high-flow, normal-flow, and low-flow periods, respectively. Variable importance in projection (VIP) analysis revealed that LWLI was the dominant landscape factor driving TN concentrations throughout the year. The proportion of build-up land primarily affected TN concentrations during the high-flow period, while the proportion of grassland and the largest patch index had more substantial effects during the normal-flow period. During the low-flow period, the proportion of forest land emerged as the most dominant factor. LWLI and the proportion of construction land exerted positive effects on TN concentrations, whereas the proportion of grassland, the largest patch index, and the proportion of forest land exhibited negative effects. When the LWLI value exceeded 0.35, the cumulative probability of abrupt changes in TN concentration during the high-flow period exceeded 95.0%, thereby elevating the risk of water quality degradation. Optimizing landscape patterns could effectively control non-point source pollution and improve water quality in headwater watersheds.

Accurate estimation of plantation biomass is of great significance for the scientific management and opera-tion of forests and for supporting China's "Dual Carbon" goals. Traditional ground survey methods have bottlenecks such as low efficiency and limited coverage. Unmanned aerial vehicle LiDAR (UAV-LiDAR) technology provides a new approach for forest aboveground biomass estimation through high-precision 3D point data. We selected 112 permanent plots of Larix olgensis plantations in Mengjiagang Forest Farm and classified them into a density gradient of nine levels from 200 to 0.5 points·m^-2. We established a forest aboveground biomass estimation model by generating subsets through repeated random pulse sampling and extracting canopy mean height (HMEAN) and canopy height ratio (CHR), and analyzed the effects of point density on indicator stability, model parameters, and prediction accuracy. The results showed that when point density decreased from 200 points·m^-2 to 0.5 points·m^-2, the mean values of HMEAN and CHR remained highly stable, but the random errors from repeated sampling increased. The mean standard deviation of HMEAN increased from 0.012 m to 0.261 m, and that of CHR increased from 0.0008 to 0.0167. The density reduction caused structural shifts in the aboveground biomass model, along with gradually expanding uncertainty in model parameters. The predictive accuracy metrics, root mean square error (RMSE), and Bias progressively increased, while the standard deviations of repeated sampling for both RMSE and Bias also showed a gradually expanding trend. The predicted mean aboveground biomass for the 112 plots remained stable, but the standard deviation of repeated predictions increased from 0.26 Mg·hm^-2 to 5.26 Mg·hm^-2. Reducing point density significantly decreased the accuracy and stability of aboveground biomass estimation. Maintaining point density above 20 points·m^-2 could control the RMSE within 16%. This study provided a valuable reference for UAV-LiDAR data acquisition and aboveground biomass estimation in L. olgensis planation.

Fraxinus mandshurica is a native high-quality timber species in Northeast China. The anatomical characteristics of its wood fibers are crucial indicators of wood performance. In the progeny test forest of F. mandshurica in Maoershan Experimental Forest, we investigated the response of fiber anatomical characteristics of whole ring, early-wood, and latewood to climate change by dendrochronology and wood anatomy methods. The results showed that juvenile F. mandshurica experienced a rapid growth period of approximately 10 years. From 2003 onwards, the ring width, fiber cell number, and total fiber cell area showed fluctuating increases, reaching peak values in 2011. At 2011, the ring width was 3749.59 μm, fiber cell number was 3750, and total fiber cell area was 760388.85 μm². There was a consistent overall correlation among the anatomical characteristics of fibers in the whole ring, earlywood, and latewood. The ring width was significantly positively correlated with both fiber cell number and total fiber cell area. The ring width, fiber cell number, and total fiber cell area of earlywood were primarily constrained by precipitation. These characteristics showed a significant negative correlation with precipitation in March, a significant positive correlation with precipitation in April, and negative correlation with temperature in June. The ring width, fiber cell number, and total fiber cell area of latewood were significantly negatively correlated with the minimum temperature and precipitation in September, and significantly positively correlated with maximum temperature in September. Under the low-temperature event, ring width, fiber cell number, and total fiber cell area decreased significantly by 19.7%, 24.2%, and 22.0%, respectively. Following the event, the resilience was 1.14, 1.14, and 1.26. Both temperature and precipitation jointly affected ring width of earlywood and latewood and fiber cell growth. The low-temperature event could significantly reduce both fiber cell number and total fiber cell area, thereby inhibiting radial growth. In response to the low-temperature event, F. mandshurica showed a significant capacity for recovery.

Phosphorus is an essential nutrient for plant growth, playing a crucial role in energy transfer and substance synthesis. The scarcity of available phosphorus in soil is an important factor restricting agricultural development and ecological restoration. Low temperature stress hinders plant physiological metabolism and inhibits soil phosphorus activation through pathways such as reducing soil enzyme activity. Phosphorus solubilizing microorgani-sms (PSM) with the capacity of cold resistance, can achieve biological activation of soil insoluble phosphorus, alleviate plant cold stress and promote growth, effectively alleviate plant phosphorus demand, mainly due to their low-temperature adaptability and phosphorus solubilizing ability. We summarized the types and distribution of cold resistant PSM, its cold resistance and phosphorus solubilization mechanisms, elaborated on its ecological functions in soil phosphorus cycling, microbial interactions, and plant growth, and explored the potential application of cold resistant PSM in sustainable agricultural development and ecological restoration in cold regions. We proposed further research directions for PSM in strain resource development, molecular mechanism analysis, and field application optimization, which would provide support for the efficient utilization of soil phosphorus resources in cold regions.

To explore the effects of nitrogen (N) and phosphorus (P) management at different growth stages on soil nutrient transformation, supply, and wheat yield formation, we conducted a field experiment at two sites of Longting (Kaifeng) and Dancheng (Zhoukou). With identical total N and P application rates, we designed four treatments with different N and P application frequencies: 50% basal, 50% jointing 2-split N + basal 1-split P (2N1P), 50% basal, 30% jointing, 20% anthesis 3-split N + basal 1-split P (3N1P), 50% basal, 50% jointing 2-split N + 70% basal, 30% jointing 2-split P (2N2P), and 50% basal, 30% jointing, 20% anthesis 3-split N + 70% basal, 30% jointing 2-split P (3N2P). We analyzed the impacts of these nitrogen and phosphorus management strategies on soil enzyme activities, soil nutrient, wheat dry matter accumulation, and grain yield. Compared with the 2N1P treatment, the 3N2P treatment significantly enhanced the activities of soil β-1,4-glucosidase and cellobiohydrolase during the wintering, jointing, and anthesis stages. In contrast, the 2N2P treatment significantly elevated the activities of soil leucine aminopeptidase and phosphatase during the jointing, anthesis, and maturity stages. The 3N2P treatment significantly increased soil available phosphorus content during the jointing and flowering stages, while the 2N2P treatment significantly increased soil available phosphorus content specifically during the anthesis stage. The 3N2P treatment significantly promoted dry matter accumulation during the anthesis and maturity stages, with an increase range of 14.3%-25.7%. Both the 2N2P and 3N2P treatments significantly improved wheat grain yield, with 3N2P treatment achieving higher yield increase of 7.8%-10.8%. In conclusion, the application of nitrogen fertilizer in two to three split doses and phosphorus fertilizer in two split doses, particularly 3N2P could enhance soil nutrient transformation and availability, promote pre- and post-anthesis dry matter accumulation in wheat, and thereby increase grain yield.