周道玮 ZHOU Daowei’s research while affiliated with Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences and other places

Phenotypic plasticity has become a core concept in ecological evolutionary developmental biology ("eco-evodevo"). This is due, to a large extent, to the major contribution of plant plasticity studies. However, the causes and consequences of phenotypic plasticity remain poorly understood. Herein, we summarize the development of research on phenotypic plasticity from an integrated perspective, including research contents and approach and brief history, with a focus on research progress and future directions. Modern plasticity research is laid on the foundations of studies that delineated the evolutionary significance of plasticity in plants. We describe the phenomenon of plant plasticity and discuss its genetic basis and evolution before exploring the underlying developmental mechanisms, associated growth and adaptation strategies, and ecological consequences. Future plasticity studies should be based on understanding and evaluating phenotypic plasticity and its adaptability from a new perspective, and closer attention should be paid to the complex network of environmental factors and plastic responses that operate under natural conditions. We conclude that understanding the eco-evolutionary implications of phenotypic plasticity should remain the emphasis of future research.

As one of the national key research and development programs, the "North Meadow Degraded Grassland Treatment Technology and Demonstration" project (2016YFC0500600) mainly focuses on the problems of intensive interference, complicated degradation mechanism, and the lack of restoration mechanism and effective treatment technology, which the meadow and meadow steppe ecological systems of China are encountered. Based on the strategic requirements of "beautiful China", "green development" and "ecological civilization" proposed by China’s 13th Five-Year Plan, the project puts emphasis on the research of grassland degradation restoration mechanism, restoration treatment technology and the ecological industry technology innovation application, develops the comprehensive treatment technology featured with replicability, portability and systematicness, as well as the new eco-industrial technology, and puts forward an overall technology solution regarding the grassland treatment for meadow degradation, providing a strong technical support for the harmonious development of China’s grassland animal husbandry and ecological environment, and the stable income increase of the herdsmen.

Understanding of the accumulation and decomposition processes of above-ground litter is of importance for us to study its ecological function and service in terrestrial ecosystems. The current paper first reviews the accumulation and decomposition processes of above-ground litter in terrestrial ecosystem and factors that affect these two ecological processes, then summarizes the ecological effects of above-ground litter in terrestrial ecosystem as a result of its accumulation and decomposition. Finally, under the view of global climate change, based on previous research progress, we review the perspectives of research on above-ground litter in terrestrial ecosystem. On the temporal scale, the accumulation of above-ground litter commonly follows the plant life cycle, and it is also regulated by environment factors, such as climatic conditions, soil temperature and moisture. On the large spatial scale, the accumulation of above-ground litter is primarily controlled by hydrothermal factors, resulting in the change in vegetation type, which show a decreased trend with the elevated latitude. However, on the local scale, apart from the constraints of hydrothermal factors, the accumulation of above-ground litter are also impacted by community structure, soil conditions, activities of herbivores, which shows more variability. Human disturbance is also an important factor that induces change of terrestrial vegetation cover and litter accumulation, and in many cases the changes are even irreversible. The decomposition processes of above-ground litter in terrestrial ecosystem include leaching, photo-degradation, soil animal and microbial decomposition. These decomposition processes occur simultaneously and interactively. Although still it is not well known now, distinguishing these decomposition process and fate of decomposition products with them are of importance for understanding the nutrient recycle in terrestrial ecosystem. Litter decomposition firstly is determined by its type, chemical composition, species diversity, but also affected by decomposer community and abiotic environment factors. Among these factors, the relationships between decomposition and litter chemical traits, species diversity and soil nutrient status are the key focus of this study. Through its accumulation and decomposition, above-ground litter has significant effects on terrestrial ecosystem physically, chemically and biologically. Currently, there are ample studies on the physical and chemical properties of above-ground litters, but there are very few studies on the biological property of above-ground litter, especially for the effects above-ground litters on vegetation that are still controversial as they are limited by complicated factors, including litter quantity, environment condition, the traits from impacted plants, even some unknown factors by now. Global climate change may change the accumulation and decomposition of above-ground litter and their ecological effects on the distribution, growth and traits of terrestrial plants in terrestrial ecosystem, through changes of climate and soil conditions. Under the global climate change, it is necessary to study the litter production and trait change on the spatial scales, expound the compartment model of litter decomposition on the temporal and spatial scales, deeply analyze the relationships between above-ground litter traits and decomposition, and further reveal the ecological effects of above-ground litter when relative limited factors are integrated into analysis, understand and predict the impact of above-ground litter on terrestrial ecosystem function and service under the scenario of the future environment change.

Grassland fire is a major disturbance to ecosystems and economies throughout the world. Research on the spatial pattern of grassland fire is therefore important in understanding the dynamics of fire disturbance and providing evidence for fire management and prevention. In this study we used a spatial point process modeling approach to study the factors contributing to fire occurrence in the Hulunbeir grassland of the Inner Mongolia Autonomous Region. In previous studies, Ripley' K function, Kernel density and Poisson model have been used in the studies of spatial-temporal pattern of forest fires. But the distribution pattern of grassland fires was usually described by overlaying fire points on top of the administrative districts or study regions. The properties of spatial distribution, such as clustering, dispersion, randomness, were often omitted. In this study, Repley's K function was used to investigate the spatial distribution pattern of human-caused fires in the Hulunbeir grassland. The distribution of fire locations was found to be spatially clustered in the months of fire season and between years. The distances of spatial cluster distribution were less than 250km, 265km, 245km, 200km and 245km in April, May, June, September and October respectively. The statistical test showed that the cluster distributions were significant except for October. The distances of spatial cluster distribution were less than 210km, 280km, 260km, 220km and 220km in 1976-1980, 1981-1984, 1985-1988, 1989-192 and 1993-1996 respectively. All the cluster distributions were significant. The spatial distribution densities of human-caused grassland fires and the impacting factors including residential locations, roads and fields were calculated by the function of Kernel density. The results showed that human-caused grassland fires were widely distributed and the main "hot-spot" was in the extent of 123. 05-124.82°E, 48. 25-50. 21°N. The second "hot-spot" had four regions and the center locations were: 117. 52° E,49. 51° N; 120. 73°E,49. 24°N;121. 94°E,48. 74°N;123. 73°E,50. 58°N. The "hot-spots" of residential points and fields were distributed in the east and middle of the study area. The "hot-spot" of roads was more widespread than the residential points and fields. The spatial distribution density of human-caused grassland fires was significantly correlated with the impacting factors (residential points, roads, fields, weather and topography) and the Pearson coefficients were 0. 448, 0.236, 0. 602, 0. 161 and -0. 042 respectively (P<0. 001). The spatial patterns of fire sources (residential points, roads and fields) are found to be more closely associated with the spatial density of human-caused grassland fires. The correlation of weather with the spatial pattern of grassland fire was at a lower degree than these of residential points, roads and fields. It showed that the weather condition was not a limiting factor in affecting the occurrence of human-caused grassland fire in the fire season. Overall, the most important factors impacted human-caused grassland fire occurrence were the spatial distribution of fire sources (residential points, roads and fields). Topography has negative correlation with grassland fire occurrence. The reason may be that the human activities decreased with the increase of slope. In each month of fire seasons, the spatial distribution pattern of human-caused grassland fires was also mainly impacted by the distribution of fire source (residential points, roads and fields). The methods developed in this study can be applied to predict human-caused grassland fire risk, aiding decisions in preventative management strategies of grassland fires.