Spatio-Temporal Variations of Soil Active Layer Thickness in Chinese Boreal Forests from 2000 to 2015

The soil active layer in boreal forests is sensitive to climate warming. Climate-induced changes in the active layer may greatly affect the global carbon budget and planetary climatic system by releasing large quantities of greenhouse gases that currently are stored in permafrost. Ground surface temperature is an immediate driver of active layer thickness (ALT) dynamics. In this study, we mapped ALT distribution in Chinese boreal larch forests from 2000 to 2015 by integrating remote sensing data with the Stefan equation. We then examined the changes of the ALT in response to changes in ground surface temperature and identified drivers of the spatio-temporal patterns of ALT. Active layer thickness varied from 1.18 to 1.3 m in the study area. Areas of nonforested land and low elevation or with increased air temperature had a relatively high ALT, whereas ALT was lower at relatively high elevation and with decreased air temperatures. Interannual variations of ALT had no obvious trend, however, and the ALT changed at a rate of only −0.01 and 0.01 m year−1. In a mega-fire patch of 79,000 ha burned in 2003, ΔALT (ALTi − ALT2002, where 2003 ≤ i ≤ 2015) was significantly higher than in the unburned area, with the influence of the wildfire persisting 10 years. Under the high emission scenario (RCP8.5), an increase of 2.6–4.8 °C in mean air temperature would increase ALT into 1.46–1.55 m by 2100, which in turn would produce a significant positive feedback to climate warming

Deserts and Desertification

A desert is an ecosystem in an arid zone in which sand dunes cover the land and sandstorms often occur. Although desert vegetation is sparse, it plays an important role in ecosystem structure and function. Desertification is one of the most severe environmental problems today. Land desertification can be controlled through many measures, such as eco-villages, eco-agriculture, biodiversity conservation, and the combination of engineering and biology. This edited volume provides new insights into the pattern of desert ecosystems and the progress of desertification control. It is a useful resource for researchers in ecology, forestry, and land desertification control

Event-based probabilistic risk assessment of livestock snow disasters in the Qinghai–Tibetan Plateau

Understanding risk using quantitative risk assessment offers critical information for risk-informed reduction actions, investing in building resilience, and planning for adaptation. This study develops an event-based probabilistic risk assessment (PRA) model for livestock snow disasters in the Qinghai–Tibetan Plateau (QTP) region and derives risk assessment results based on historical climate conditions (1980–2015) and present-day prevention capacity. In the model, a hazard module was developed to identify and simulate individual snow disaster events based on boosted regression trees. By combining a fitted quantitative vulnerability function and exposure derived from vegetation type and grassland carrying capacity, we estimated risk metrics based on livestock mortality and mortality rate. In our results, high-risk regions include the Nyainqêntanglha Range, Tanggula Range, Bayankhar Mountains and the region between the Kailas Range and the neighbouring Himalayas. In these regions, annual livestock mortality rates were estimated as  &gt; 2&thinsp;% and mortality was estimated as  &gt; 2 sheep unit km−1 at a return period of 20 years. Prefectures identified with extremely high risk include Guoluo in Qinghai Province and Naqu, and Shigatse in the Tibet Autonomous Region. In these prefectures, a snow disaster event with a return period of 20 years or higher can easily claim total losses of more than 500&thinsp;000 sheep units. Our event-based PRA results provide a quantitative reference for preparedness and insurance solutions in reducing mortality risk. The methodology developed here can be further adapted to future climate change risk analyses and provide important information for planning climate change adaption in the QTP region.</p

Analysis and interpretation of forest fire data of Sikkim

Forest ecosystems are depleting and heading towards degradation which would adversely affect the world's socio-economic harmony. Various disasters disturb the cordial relationship of the flora and fauna and impose imbalance in the ecology as a whole; forest fire is one of its kind. India has witnessed a 125% rise in forest fire occurrences between the years 2015 and 2017. This paper presents a study of various factors and the analysis of forest fire in Sikkim. The period of 10 years, forest fire incidences, i.e., from the year 2004 to the year 2014 have been considered for the study. The forest fire data was collected from Forest and Environment Department, Government of Sikkim, and preliminary processing was performed to check for anomalies. The study observed that there has been an increased forest fire incidence over the years and highest being in the year 2009. These fire incidences have damaged a total area of 5,047.16 ha of land damaging various flora and fauna. It was observed that the maximum forest fire cases are below an altitude of 1500m, during winter months (December to February extending to March) and in sub-tropical Sal (Shorea robusta) forest. West district of Sikkim recorded the highest number of forest fire incidences and area covered followed by south and east districts; the north district was least affected. As per the visual interpretation of forest fire incidence data and literature review, the main factors responsible for forest fire in Sikkim are low rainfall, dry winter season, and type of vegetation. Also, a linear regression was performed between weather factors like average temperature (°C), relative humidity (%), and wind velocity (Km/h) on incidences of forest fire between the year 2009-2014 (n=389). It was found that the average temperature (r=0.37, Slope=9.59 and SD= ±12.00) and relative humidity (r=-0.6, Slope=-4.52, and SD=±2.68) plays a moderate linear relationship in influencing the incidences of forest fires. However, wind velocity showed almost a flat curve indicating its minimal role in influencing forest fire incidences. Parameter modelling and preparation of forest fire risk zone map would be an effective tool in preventing and managing forest fire in Sikkim

Integrated Ecosystem Assessment of Western China

Western Development is an important strategy of China Government. The ecological environment in the western region of China is very fragile, and any improper human activity or resource utilization will lead to irrecoverable ecological degradation. Therefore, the integrated ecosystem assessment in the western region of China is of great significance to the Western Development Strategy. This project, Integrated Ecosystem Assessment of Western China (MAWEC), will provide very important scientific foundations for both the central and local governments to make decisions on ecological construction, thus assuring the successful implementation of the Western Development Strategy. Meanwhile, MAWEC as one of the MA sub-global assessments is contributing to strengthen capability in boosting the development of the ecological science, interaction between different subjects, and combination between scientific research and practice, and pushing forward international cooperation in the relevant fields

INVESTIGATING THE IMPACTS OF ANTHROPOGENIC AND CLIMATIC CHANGES ON THE STEPPE ECOSYSTEM IN CHINA’S LOESS PLATEAU AND THE MIXED-GRASS PRAIRIE REGION IN SOUTHWEST OKLAHOMA, USA

Grassland ecosystems occupy approximately 40% of the earth’s terrestrial area and represent one of most important ecosystems on Earth in terms of its impacts on global food supply, carbon sequestration and maintaining biodiversity. Grassland ecosystems are very sensitive to disturbances caused by either climatic or anthropogenic changes such as changes in precipitation regimes or management practices. The objective of this dissertation is to investigate the impacts imposed by grassland restoration activities and changes in precipitation anomalies on the steppe in China’s Loess Plateau and the mixed-grass prairie in southwest Oklahoma. In chapter two, I analyzed how large-scale vegetation conservation programs affected the grassland dynamics in China’s Loess Plateau by combining remotely sensed data with socio-economic statistics. The results of this study showed that the impact of vegetation conservation programs on vegetation change in the Loess Plateau is twofold. On the one hand, vegetation conservation programs target marginal lands. Thus, significant vegetation increases due to cropland conversion and afforestation can be found in these regions. On the other hand, intensified agricultural production can be found in croplands with suitable topography and well-established irrigation systems which were not enrolled in conservation programs to offset the agricultural production loss caused by vegetation conservation programs elsewhere. In chapter three, I demonstrated a new methodology on mapping the historical distribution of grassland species in southwest Oklahoma based on the Random Forest classification algorithm. In this study, elevation, soil pH and soil clay content were found to be significant variables for predicting the distribution of C3 and C4 grassland species. With the mapped distribution of grassland species between 1981 and 2010, in chapter four, I examined the relationship between changes in precipitation anomalies and the dynamics of relative abundance of C3 and C4 grassland species in southwest Oklahoma. In this study, significant decreases of C3/C4 ratio were identified in pasture/hay fields due to the increases in C4 abundance resulting from the decreases of sparsely vegetated area between 2005 and 2010. I suspect that the increase in C4 abundance was a drought adaptation strategy adopted by ranchers. Because C4 species are more tolerant of drought conditions and thus can help to maintain stable forage/hay production when negative precipitation anomalies prevailed during the growing season of C3 species

Vegetation Dynamics Revealed by Remote Sensing and Its Feedback to Regional and Global Climate

This book focuses on some significant progress in vegetation dynamics and their response to climate change revealed by remote sensing data. The development of satellite remote sensing and its derived products offer fantastic opportunities to investigate vegetation changes and their feedback to regional and global climate systems. Special attention is given in the book to vegetation changes and their drivers, the effects of extreme climate events on vegetation, land surface albedo associated with vegetation changes, plant fingerprints, and vegetation dynamics in climate modeling