基于探索感知思维深度强化学习的自动发电控制

减少碳排放的重要途径之一是大规模引入新能源。然而,随着大规模风、光、电动汽车等新能源和分布式能源接入复杂互联电网,给电网带来严重的随机扰动问题。该文从自动发电控制角度,探索了一种动作探索感知思维的深度强化学习算法,即DDQN-AD。通过将神经网络的预测机制作为强化学习的动作选择机制,同时引入具有动作探索感知思维的AD策略,将区域控制误差与碳排放作为综合奖励函数,来获取强随机环境下的最优控制策略,进而解决分布式能源大规模接入电网所带来的随机扰动问题。对改进的IEEE标准两区域LFC模型,以及多区域多能生态系统模型进行仿真,结果显示DDQN-AD与已有的多种智能算法相比,具有更优的动态性能和在线学习能力,能够获得区域最优控制,减少碳排放。

Evaluation of Ecological Effectiveness of Protected Areas in Northwest China

Protected areas(PAs) have experienced explosive growth in Northwest China over the last three decades, but their effectiveness in representing regional ecological system diversity has not attracted considerable attention. Low effectiveness would exacerbate the conservation-development conflicts, particularly those that arise as a result of the Great Western Development Strategy(GWDS). Thus, an assessment of the effectiveness of the PA network has become quite important. We proposed natural vegetation communities to represent regional ecological system diversities, and proposed Global 200 Priority Ecoregions, Important Bird Areas, and ecosystem function regions to represent important conservation areas. To determine their effectiveness, we studied the extent to which ecological system diversities and important conservation areas are represented by the existing 96 PAs. Our results indicated that the total coverage of vegetation communities in PAs in Northwest China is not sufficiently comprehensive. As the PA system has expanded, the growth in the total area of the PAs has been greater than that of their vegetation community richness. While most of the important conservation areas are covered by PAs, some regions have not yet reached the 10% threshold; further, PAs are distributed unevenly and conservation gaps remain in the region. Therefore, these regions should receive more attention when planning new PAs. It is vital that more biodiversity datasets and assessment of ecosystem function regions are integrated in order to provide a basis for the government to formulate appropriate protection and development strategies.

Nematode Diversity in Phaeozem Agroecosystems of Northeast China

The diversity and distribution patterns of soil nematode communities in phaeozem agroecosystems of Northeast China were assessed to evaluate nematode taxonomic diversity and functional diversity in relation to climatic condition and soil characteristics in human modified landscape. Along the latitudinal gradient, soil samples were collected from north （Hailun） to south （Gongzhuling） down to a depth of 100 cm with intervals of 030, 20-40, 40-60, 60-80, and 80-100 cm. The nematode abundance and taxonomic diversity （generic richness） were lower at Hailun than at other sites, and higher values of evenness were observed at Hailun and Harbin than at Dehui and Gongzhuling. Nematode faunal analysis revealed that soil food web at Hailun was sueeessionally more mature or structured, and the environment little disturbed, while at Harbin and Gongzhuling, the soil food web was degraded with stressed environment. The environmental variables relevant in explaining the patterns of nematode distribution and diversity in phaeozem agroecosystems, using canonical correspondence analysis （CCA）, were the mean annual temperature, total nitrogen, electrical conductivity, mean annual precipitation, and other soil properties. Among these variables, the mean annual temperature was a relatively important factor, which could explain 29.05% of the variations in nematode composition.

Soil Microbial Activity and Functional Diversity in Primeval Beech Forests

Virgin forests are unique ecosystems, which can be used as etalon for basic biocoenotic investigation. Soil microorganisms are very sensitive reagents on influence of biotical factors, and at the same time are the active producers of phytotoxic and phytostimulating exometabolites. Studies of soil microbiota were conducted in virgin beech forests of Shyrokoluzhansky massif of the Carpathian Biosphere Reserve. It was found the ratio and the number of different ecological-trophic groups of soil microorganisms changes with altitude. So the number of ammonificators with increasing of altitude above sea level was reduced. The soil at altitude of 1,100 meters above sea level was characterized by minimum content of organotrophes -1.22 × 10^6 （CFU-colony forming units/lg.a.d.s.）. At the altitude of 500 meters content of ammonificators increased at six times and was 7.07 ×10^6 CFU/lg.a.d.s., which indicates to accumulation of the soil organic matter. Similar changes occurred with the number of bacteria which are using mineral forms of nitrogen for their nutrition. Their maximum quantity （4.32 × 10^6 CFU/lg.a.d.s.） was in the soil of biotope disposed at altitude of 500 meters above sea level. Fluctuations in the number of soil micromycetes of virgin forest ecosystems have not been as significant as the bacterial microbiota （within 17 ×10^3-28 × 10^3 CFU/lg.a.d.s.）. Among a wide spectrum of bacterial microbiota were isolated strains with high phytostimulating action.

Variation in the methods leads to variation in the interpretation of biodiversity-ecosystem multifunctionality relationships

Aims Biodiversity is often positively related to the capacity of an ecosystem to provide multiple functions simultaneously(i.e.multifunctionality).However,there is some controversy over whether biodiversity–multifunctionality relationships depend on the number of functions considered.Particularly,investigators have documented contrasting findings that the effects of biodiversity on ecosystem multifunctionality do not change or increase with the number of ecosystem functions.Here,we provide some clarity on this issue by examining the statistical underpinnings of different multifunctionality metrics.Methods We used simulations and data from a variety of empirical studies conducted across spatial scales(from local to global)and biomes(temperate and alpine grasslands,forests and drylands).We revisited three methods to quantify multifunctionality including the averaging approach,summing approach and threshold-based approach.Important Findings Biodiversity–multifunctionality relationships either did not change or increased as more functions were considered.These results were best explained by the statistical underpinnings of the averaging and summing multifunctionality metrics.Specifically,by averaging the individual ecosystem functions,the biodiversity–multifunctionality relationships equal the population mean of biodiversity-single function relationships,and thus will not change with the number of functions.Likewise,by summing the individual ecosystem functions,the strength of biodiversity–multifunctionality relationships increases as the number of functions increased.We proposed a scaling standardization method by converting the averaging or summing metrics into a scaling metric,which would make comparisons among different biodiversity studies.In addition,we showed that the range-relevant standardization can be applied to the threshold-based approach by solving for the mathematical artefact of the approach(i.e.the effects of biodiversity may artificially increase with the number of functions considered).Our study highlights different approaches yield different results and that it is essential to develop an understanding of the statistical underpinnings of different approaches.The standardization methods provide a prospective way of comparing biodiversity–multifunctionality relationships across studies.

A National Key R&D Program: Technologies and Guidelines for Monitoring Ecological Quality of Terrestrial Ecosystems in China

Ecological quality is defined as the stability, adaptability and resilience of an ecosystem. Monitoring and assessing ecological quality are important bases for China’s ecological civilization construction. The national key research and development program "Technologies and guidelines for monitoring ecological quality of terrestrial ecosystems in China", launched in July 2017, includes plans to study the observation technologies and provide guidelines on the ecological in-situ observation, the regional biodiversity and ecosystem function monitoring and its applications, all of which contribute to national ecological quality assessment. A year after its implementation,some important progress has been achieved, such as building the indicator system for comprehensive monitoring of ecological quality and improvement of the methods, mass data transmission, infrared camera-based monitoring of biodiversity, multi-angle automatic spectral observation systems, and unmanned aerial vehicle(UAV) based desert monitoring. We have organized this special issue and attempted to introduce the monitoring techniques and assessment methods on ecological quality from different perspectives in order to further promote the development of ecology and its observation methods.

Land Use and Ecological Civilization: A Collection of Empirical Studies

The goal of ecological civilization construction is to realize the harmonious coexistence of human and nature.Land is the spatial carrier of ecological civilization construction.Land use types or behaviors reflect the level of intensive use of land resources,leading to different ecological environmental effects,thereby affecting the level of regional ecological civilization construction.This issue,"Land Use and Ecological Civilization",discusses the theory and method of land use management in the view of ecological civilization from the aspects of land use efficiency,land use change,land multi-functional trade-off,land ecosystem service and land ecological risk by selecting 14 representative papers,providing practical reference for the formation of the land use mode and behavioral system of ecological civilization.With abundant research levels,this issue covers varied research scales such as village,county and province,various landform types such as plain and hill,and typical land use areas at home and abroad such as East China,Central China,Northwest China,Yangtze River Economic Belt and Japan.Being frontier and practical,the multidisciplinary research methods in this issue include literature research method,fractal theory,qualitative comparative analysis,VAR model,and econometrics,among others.Focusing on the prominent problems in the process of land use,this issue deeply discusses the hot topics such as land ecological efficiency,spatial behavior characteristics,land use structure optimization and ecological risk assessment.This issue not only reviews the current literature on urgent land use issues such as arable land abandonment and land use risk,but also tries to conduct trade-off and synergy analysis on the varied functions of the rural landscape and ecosystem,thus providing a theoretical and empirical basis for solving land use problems from the perspective of ecological civilization.This issue reflects the realistic urgency of guiding land use with the concept of ecological civilization,and provides theoretical guidance and technical support from the aspects of methods and research framework.Finally,this issue proposes five hot topics in the field of land use research from the perspective of ecological civilization in the future,namely,ecological management of land use structure,ecological evolution mechanism of land use process,land ecological use mode,early warning and regulation of land ecological security pattern,ecological management and control of land use behavior.

The relationship between species diversity and ecosystem function (productivity) of the late Middle Permian brachiopods community at the region of Hechuan,Chongqing,China

The relationship between species diversity and ecosystem function is a hot topic in ecology and environics. This paper investi- gates the evolution of diversity of the late Middle Permian brachiopods community in Hechuan, Chongqing, China, and dis- cusses the relationship between species diversity and community productivity in terms of the geohistorical development. This paper shows that the species diversity is externalized by several indexes, and the relationship between diversity and productiv- ity is too complex to be described by a single assumption. The relationship between species diversity and community produc- tivity is restricted by environment and community evolution. When the community succeeds normally, the relationship be- tween species richness index, species diversity index, and species evenness index to productivity is in linear dependence rela- tion to each other, which is met with the third assumption. But, when the environment interference surpasses the beating capa- bility of the community, not only the community succession will be terminated and be replaced by another one, but also the relationship between species richness index, species diversity index, and species evenness index to productivity is also in- versed to negative correlation by the interference from environment. Only the relationship between ecological dominance and productivity is in linear dependence relation to each other and approximately met with the third assumption. It is illustrated that the assumption that the productivity is in linear dependence relation with diversity should be established on the presupposition that the community succession is normal.

Linking the spatiotemporal variation of litterfall to standing vegetation biomass in Brazilian savannas

Aims Litterfall at a global scale is affected by climate,edaphic features and vegetation structure,with litter production increasing from grasslands to forests following the rise in standing biomass.However,at landscape scales,the same relationship between litter production and vegetation structure has rarely been studied and comparisons of litterfall patterns between adjacent,structurally distinct communities are lacking.Here,we use a standardized methodology to describe the structural differences among four savanna physiognomies and analyze their relationship with changes in litterfall across the Cerrado.Methods We evaluated the woody vegetation structure and composition in 48 sites,equally distributed across four physiognomies and monitored the monthly litter production from April 2014 to March 2015.Important Findings Results showed that the density,basal area,cylindrical volume and aboveground biomass of woody vegetation differ among physiognomies,increasing consistently from cerrado ralo,cerrado típico,cerrado denso and cerradão.Indeed,we found a strong and positive relationship between aboveground biomass and annual litter production,with litter yield increasing from 0.9 to 8.4 Mg ha^(−1)across different physiognomies,following the increment in vegetation structure.Monthly production was seasonal and similar among vegetation types,increasing during the dry season.Leaves comprised the dominant fraction(approx.85%)and litterfall seasonality primarily resulted from the concentration of leaf shedding during dry months.However,the temporal pattern of litterfall throughout the year showed a gradual reduction in the seasonality from open to closed vegetation types,likely following the decrease of deciduous species abundance in the plant community.Our results showed that changes in vegetation structure may affect spatial and temporal litterfall patterns in different physiognomies,which co-occur across the Cerrado landscape,with potential implications for the overall functioning of this ecosystem.Moreover,these findings highlight the use of standardized methods as essential to correctly compare litterfall patterns among different environments.

Effects of biodiversity,stand factors and functional identity on biomass and productivity during the restoration of subtropical forests in Central China

Biodiversity is found to have a significant promotion effect on ecosystem functions in manipulation experiments on grassland communities.However,its relative role compared with stand factors or functional identity is still controversial in natural forests.Here,we examined their relative effects on biomass and productivity during forest restoration.We investigated stand biomass and productivity for 24 plots(600 m2)across restoration stages in the subtropical forests of Mt.Shennongjia,Central China.We measured five key functional traits and calculated functional diversity(functional richness,evenness and dispersion)and community-weighted mean of traits.We used general linear models,variation partitioning methods to test the relative importance of stand factors(density,stand age,maximum height,etc.),functional identity,species and functional diversity on biomass and productivity.Our results illustrated that stand biomass and productivity increased significantly as forest restoration,and that community species richness increased,while functional dispersion decreased significantly.Variation partitioning analyses showed that diversity had no significant pure effects on biomass and productivity.However,diversity may affect biomass and productivity through the joint effect with stand factors and functional identity.Overall,we found that stand factors had the strongest effect on biomass and productivity,while functional identity significantly affects productivity but not biomass,suggesting that modulating stand structure and species identity are effective ways to enhance forest carbon storage and sequestrations potential in forest management.

Using the response-effect trait framework to disentangle the effects of environmental change on the ecosystem services

Functional traits play a vital role in mediating the responses of ecosystem services to environmental changes and in predicting the functioning of the ecosystem.However,the connection between functional traits and ecosystem services has become increasingly intricate due to climate change and human activities for degraded ecosystems.To investigate this relationship,we selected 27 sampling sites in the Yanhe River Basin of the Chinese Loess Plateau,each containing two types of vegetation ecosystems:natural vegetation and artificial vegetation ecosystems.At each sampling site,we measured ecosystem services and calculated the composition index of community traits.We established a response–effect trait framework that included environmental factors such as climate,elevation and human activities.Our results showed that leaf tissue density(LTD)was the overlapping response and effect trait when responding to climate change.LTD is positively correlated with mean annual temperature and negatively correlated with supporting services.Under the influence of human activities,leaf nitrogen content and leaf dry matter content were carriers of environmental change.Comparing the two vegetation ecosystems,the relationship between functional traits and ecosystem services showed divergent patterns,indicating that human activities increased the uncertainty of the relationship between functional traits and ecosystem services.Trait-based ecology holds promise for enhancing predictions of ecosystem services responses to environmental changes.However,the predictive ability is influenced by the complexity of environmental changes.In conclusion,our study highlights the importance of understanding the complex connection between functional traits and ecosystem services in response to climate changes and human activities.