应用生态学报最新文献

Tree growth includes primary growth and secondary growth. The growth activity and dormancy cycle of trees can affect forest productivity and carbon sequestration capacity. Therefore, it is of great significance to examine the effects of environmental conditions (e.g., photoperiod, temperature and water) on tree growth for understanding the responses of trees to climate change and predicting forest productivity and carbon sequestration capacity under the background of global climate change. We reviewed the effects of photoperiod, temperature and water conditions on the primary and secondary growth of trees, and revealed the physiological mechanisms underlying their impacts on the synchronization or asynchronization between primary and secondary growth of trees. The shortcomings of the existing research were pointed out. For example, less attention had been paid to the enrionmental response and adaptation of root growth, as well as the physiological mechanism of the effect of light, temperature and water on tree growth. Research on the growth of underground roots should be strengthened in the future, and more attention should be paid to the physiological changes in the process of tree growth affected by environmental factors. Furthermore, the source and sink limitation theory and the process-based prediction model should be improved, aiming to provide a scientific basis for predicting forest productivity and carbon sequestration capacity and putting forward scientific policies of forest management.

The community structure of natural mature forests is determined by long-term forest succession, characterized by rational structure, rich biodiversity, and high ecological function. Understanding the spatial structure and formation mechanisms of mature forests is a fundamental prerequisite for forest management. We analyzed four structure parameters, including diameter structure, angular scale, size ratio, and mixture degree, as well as the Hegyi competition index, of secondary Quercus mongolica (Mongolian oak) mature forests in the mountainous area of eastern Liaoning Province. The results showed that Q. mongolica predominated the tree layer. In the sapling layer, Q. mongolica, Tilia amurensis, and Acer pictum were the dominant species. In the seedling layer, Acer pseudosieboldianum, T. amurensis, and A. amurensis dominated, with very few Q. mongolica seedlings. The overall diameter distribution of the stand showed an inverse "J" shape, while the diameter distribution of Q. mongolica, the dominant tree species, followed a normal distribution. The horizontal spatial structure of the stand was generally randomly distributed, with an average angle scale of 0.505, size ratio of 0.219, and mixture degree of 0.670 for Q. mongolica. From the perspective of spatial structure binary distribution, Q. mongolica individuals which had a random distribution exhibited greater growth advantages and higher levels of mixing, in comparison to other distribution types. Randomly distributed dominant and subdominant individuals made up nearly half individuals in the stand, and showed a high degree of mixing with surrounding trees. The stand-level individual tree competition index decreased with increasing diameter classes. When the diameter at breast height exceeded 20 cm, the competition index tended to stabilize (ΔCI<2). The competitive radius of individual Q. mongolica trees was 8 m, with intraspecific competition as the main pressure. Other species experienced competition pressure primarily from interspecific sources. Our results suggested that competition played an important role in shaping the spatial structure of secondary Q. mongolica mature forests.

Species distribution models (SDMs) are valuable tools in predicting species distribution ranges and the suitable habitats, which are based on environmental conditions and species distribution data. These models encompass correlative models, mechanistic models, and mechanistic-correlative models. In the field of marine science, SDMs have been extensively used for predicting the spatial distribution patterns of various marine organisms including fish, mammals, algae, et al. However, the application of SDMs in predicting the distribution of macrobenthos remains scarce. Understanding the distribution of macrobenthos, the integral components of marine ecosystems, has significant implications for ecological conservation and resource management. We reviewed common methodologies employed in SDMs and presented case studies using different models to predict the distribution patterns of marine macrobenthos. Further, we emphasized the use of correlative and mechanistic models to analyze the impact of climate change on the spatial distribution of marine macrobenthos. Finally, we discussed the challenges and prospects associated with SDMs. With the advances in remote sensing technology and modeling techniques, SDMs are becoming increasingly pivotal in marine ecological research, which could offer a robust scientific foundation for addressing climate change and preserving marine biodiversity.

Atmospheric deposition provides a stable iron source for peatlands. The influences of Fe input on methane (CH₄) productions and the underlying mechanisms remain unclear. We conducted a microcosm experiment with peat sediments collected from the Qinghai-Tibet Plateau of China to explore the effects of ferrihydrite reductionfor CH₄ productions in peatlands by using geochemical analyses including ⁵⁷Fe Mössbauer spectroscopy and three-dimensional fluorescence spectroscopy (3D-EEM) in combination with high-throughput sequencing of 16S rRNA and real-time fluorescence quantitative PCR (qPCR). Results showed that ferrihydrite reduction significantly increased CH₄ production, being 30 times of that under the control. Selective extractions for iron oxides and ⁵⁷Fe Mössbauer spectroscopy measurements revealed that no crystalline secondary iron minerals were formed during the ferrihydrite reduction process. The addition of ferrihydrite enhanced the degradation of dissolved organic matter (DOM) in peat soil, resulting in a reduction in the concentration of dissolved organic carbon (DOC). Furthermore, the relative abundance of typical fermentative microorganisms in peat sediments, including Acidobacteriota and Bacteroidota, significantly increased. Such a result indicated that reduction of ferrihydrite accelerated organic matter decomposition and increased substrate concentration required for methanogenesis. Furthermore, a co-increase in relative abundance of Geobacter, Geothrix, and Methanobacterium in the ferrihydrite-amended group suggested a potential synergistic interaction that may promote the CH₄ production. Our results demonstrated that ferrihydrite reduction could significantly enhance CH₄ production and play a vital role in regulating CH₄ emissions in peatlands.

Litter decomposition significantly influences the carbon (C) dynamics of terrestrial ecosystems. Solar radiation is not only essential for photosynthetic C fixation and primary productivity, but also can directly or indirectly promote litter decomposition through photodegradation. Recently, photodegradation has been identified as a key factor driving litter decomposition and potentially impacts terrestrial C cycle. To enrich and develop the theory of litter decomposition, we summarized the mechanisms and main driving factors of photodegradation, and compared the responses of photodegradation to environment and climate changes at different scales. Photodegradation primarily includes photomineralization, photoinhibition, and photofaciliation, each affecting litter decomposition differently under various environmental conditions. Photodegradation is closely related to factors such as solar radiation, litter traits, temperature, moisture, microorganisms, and vegetation cover. The interactions among these factors complicate the patterns of photodegradation. Finally, we identified the main issues in litter photodegradation research and prospected future research directions. We emphasized the needs for in-depth exploration of photodegradation pathways and intrinsic mechanisms, quantification of its interactive effects with environmental factors, and optimization of traditional carbon turnover models.

The Vaganov-Shashkin (VS) and VS-Lite models are the most widely used physiological processes-based models of tree-ring width. Both models can reveal the intrinsic response mechanism between tree-ring width and external climate factors. The VS model is commonly applied in climate reconstruction, wood phenology prediction, and the simulation of cambial activity, while the VS-Lite model is primarily applied in forecasting growth trends of forest. We collected papers related to the VS and VS-Lite models published between 2005 and 2023, and reviewed the fundamental principles, parameter settings, and historical development of both models, as well as the their applications in research areas of dendroclimatology, xylem phenology, and forest ecology. Then, we summarized the current issues with the models and proposed future research directions. To increase confidence in the simulation results, it is essential to optimize the parameter adjustment method of the models, consider the impact of multiple environmental factors on the physiological processes of trees, and strengthen the comparative study of the VS and VS-Lite model with other vegetation ecological models.

Paddy fields are recognized as significant sources of methane (CH₄) emissions, playing a pivotal role in global climate change. Elevated atmospheric carbon dioxide (CO₂) concentrations (e[CO₂]) exert a profound influence on the carbon cycling of paddy fields. Understanding the effects of e[CO₂] on CH₄ emissions, as well as the underlying microbial processes, is crucial for enhancing carbon sequestration and reducing emissions in paddy fields. We reviewed the impacts of e[CO₂] on CH₄ emission in paddy fields, focusing on the activity, abundance, community structure, and diversity of carbon-cycling-related microbes. We also delineated the roles of various microbial processes in mitigating CH₄ emissions under e[CO₂], as well as the primary environmental determinants. Overall, the type of e[CO₂] experimental platforms, duration of fumigation, concentration gradients, and the methods of CO₂ enrichment all influence CH₄ emissions from paddy fields. e[CO₂] initially stimulates CH₄ emissions, which may decrease over time, indicating an adaptability of the methane-emitting microbial community to e[CO₂]. This response exhibits a trend of initial attenuation followed by an intensification of the positive effects on CH₄ emissions. Experiments with abrupt increase of CO₂ concentration might overestimate CH₄ emissions. The impact of e[CO₂] on microbial processes is predominantly characterized by enhanced activities and abundance of methanogens, aerobic and anaerobic methanotrophs. It significantly alters the community composition and diversity of methanotrophs, with minimal effects on methanogens and anaerobic methanotrophic communities. Finally, we outlined future research directions: 1) Integrated investigations into the effects of e[CO₂] on CH₄ emissions, methanogenesis, and both aerobic and anaerobic methanotrophs in paddy fields could elucidate the mechanisms underlying the impacts of climate change on CH₄ emissions; 2) Long-term studies are essential to understand the mechanisms of e[CO₂] on CH₄ emissions and associated microbial processes more accurately and realistically; 3) Multi-scale (temporal and spatial), multi-factorial (CO₂ concentration, temperature, atmospheric nitrogen deposition, and water management practices), and multi-methodological (observational, data, and model integration) research is necessary to effectively reduce the uncertainties in assessing the response of CH₄ emissions in paddy fields and related microbial processes to e[CO₂] under future climate change scenarios.

The identification of key areas for ecological restoration of national land space based on the ecological security pattern is an important way to balance environmental protection and social development in the new era. With the Taihu Lake city cluster as the study area, we identified the ecological source from both structural and functional aspects, and used the minimum cumulative resistance model to identify the ecological corridors on the basis of constructing the resistance surface. Coupled the landscape ecological risk evaluation, we determined the appropriate width of each ecological corridor in the study area, identified the key restoration zones through the circuit theory. Then, we constructed the ecological security pattern of "six zones and four belts" and controlled by zoning. The results showed that the 32 ecological source areas in the Taihu Lake city cluster presented a spatial pattern of "more in the east and less in the west-mountains and lakes are connected" and 70 ecological corridors were concentrated in the west and the center. The suitable width of most of the ecological corridors was 1500-2000 m. The ecological restoration zones of the national land space were concentrated in the eastern part of the Lake Taihu, Changxing County, and Liyang City. According to the characteristics of the study area and the actual situation of the restoration area, we proposed specific protection and restoration measures, such as protecting the core ecological source, optimizing and restoring the important corridors, and reasonably planning land use of the ecological pinch points and obstacle points.

Jiangxi Province is one of the first ecological civilization demonstration provinces in China. Understan-ding the impacts of meteorological conditions on ecosystem regulatory services is beneficial for conducting ecological protection and restoration work. Based on MODIS data, net primary productivity data, and monthly meteorological data from 2000 to 2022, we used models such as water balance equation and soil loss equation to measure the four regulatory service functions of ecosystem in Jiangxi Province, including carbon sequestration, oxygen release, water conservation and soil conservation. We used trend analysis and partial correlation analysis methods to analyze the spatio-temporal patterns and meteorological influencing factors of those four regulation service functions. The results showed that from 2000 to 2022, the annual average values of carbon sequestration and oxygen release in Jiangxi Province were 178.8 and 130.0 g·m^-2, respectively, with annual increases of 0.4 and 0.3 g·m^-2. The spatial distribution of both services was consistent, and the average annual carbon sequestration and oxygen release showed an upward trend in 77.3% regions of Jiangxi Province. The average water conservation and soil retention in Jiangxi Province were 591.8 mm and 723.8 t·hm^-2, respectively, with similar spatial distributions. The annual increases were 5.6 mm and 3.7 t·hm^-2. The soil conservation and water conservation functions of 73.3% and 69.3% regions in Jiangxi Province were steadily improved. Vegetation carbon sequestration and oxygen release was significantly correlated with temperature at monthly scale and seasonal scale. The partial correlation coefficient of those two factors was higher than other factors, which was an important meteorological factor affecting the carbon sequestration and oxygen release function of ecosystem. Precipitation, which was the most important meteorological factor, had a significant positive correlation with water conservation and soil conservation at monthly, seasonal and annual scales. Our results revealed the impacts of climate change on ecosystem regulatory service functions in Jiangxi Province from 2000 to 2022, which could provide scientific and technological support for effectively guaranteeing ecosystem protection and restoration in Jiangxi Province and improving the quality and efficiency of ecological civilization construction.

Exploring the response of leaf anatomical structure to climate warming is helpful for understanding the adaptive mechanisms of trees to climate change. We conducted a warming experiment by transplanting seedlings of Larix gmelinii from 11 provenances to two common gardens, and examined the response of leaf anatomical structure to climate warming. The results showed that warming significantly increased leaf thickness (T_L), upper epidermal mesophyll thickness (T_UEM), lower epidermal mesophyll thickness (T_LEM), endodermal thickness (T_E), vascular bundle diameter (D_VB), transfer tissue thickness (T_TT), and the percentage of mesophyll thickness to T_L(P_MT), and significantly decreased the upper epidermal thickness (T_UE) and the percentage of epidermal thickness to T_L (P_E). The mesophyll thickness was positively associated with chlorophyll concentration and maximum net photosynthetic rate. The responses of T_L, T_UEM, T_LEM, T_E, D_VB, T_TT, T_UE, P_MT and P_E to warming differed among all the provenances.As the aridity index of the original site increased, the magnitude of the warming treatment's effect decreased for T_L, T_UEM, T_LEM, T_TT and P_MT, and increased for T_UE and P_E. Warming increased the thickness and proportion of profit tissue (e.g., mesophyll) and decreased the thickness and proportion of defensive tissue (e.g., epidermis), and those changes varied among provenances. L. gmelinii could adapt to climate warming by adjusting leaf anatomical structure, and this ability was weak for trees from provenance with high aridity index.