Effects of forest fires on the permafrost environment in the northern Da Xing'anling (Hinggan) mountains, Northeast China

Forest fires are a significant factor that affects the boreal forest carbon distribution which emits carbon into the atmosphere and leads to carbon redistribution among carbon pools. However, knowledge about how much carbon was transferred among pools and the immediate changes in soil nutrient contents in areas that were burned by fires of various severities are still limited. In this study, we surveyed eight wildfire sites that are located in northeast China within three months after the fires occurred. Our results indicate that the total soil nitrogen, phosphorus, and organic carbon contents significantly increased after moderate- and high-severity fires. The carbon emissions were 3.84, 5.14, and 12.86 Mg C/ha for low-, moderate-, and high-severity fires, respectively. The amount of carbon transferred among pools increased with fire severity except for the charcoal pool, storing the highest amounts of carbon in moderate-severity fires. Although the charcoal and ash pools accounted for a small proportion of the total ecosystem, they are important for biogeochemical cycles and are worthy of attention. The carbon redistribution information in our study is important for accurately estimating the forest carbon budget and providing crucial parameters for forest carbon cycling models to incorporate the carbon transfer process.

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46-Year (1973–2019) Permafrost Landscape Changes in the Hola Basin, Northeast China Using Machine Learning and Object-Oriented Classification

Remote Sensing ◽

10.3390/rs13101910 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1910

Author(s):

Raul-David Șerban ◽

Mihaela Șerban ◽

Ruixia He ◽

Huijun Jin ◽

Yan Li ◽

...

Keyword(s):

Forest Fires ◽

Northeast China ◽

Support Vector ◽

Resource Exploitation ◽

Object Based Image Analysis ◽

Detection Analysis ◽

Object Based ◽

Svm Algorithm ◽

Engineered Systems

Land use and cover changes (LUCC) in permafrost regions have significant consequences on ecology, engineered systems, and the environment. Obtaining more details about LUCC is crucial for sustainable development, land conservation, and environment management. The Hola Basin (957 km2) in the northernmost part of Northeast China, a boreal forest landscape underlain by discontinuous, sporadic, and isolated permafrost, was selected for the case study. The LUCC was analyzed using the Landsat archive of satellite images from 1973 to 2019. A thematic change detection analysis was performed by combining the object-based image analysis (OBIA) and the Support Vector Machine (SVM) algorithm. Four types of LUCC (forest, grass, water, and anthropic) were extracted with an overall accuracy of 80% for 1973 and >90% for 1986, 2000, and 2019. Forest, the dominant class (750 km2 in 1973), declined by 88 km2 (11.8%) from 1973 to 1986 but had a recovery of 78 km2 (12.5%) from 2000 to 2019. Grass, the second-largest class (187 km2 in 1973), increased by 86 km2 (46.5%) between 1973 and 1986 and decreased by 90 km2 (40%) between 2000 and 2019. The anthropic class continuously increased from 10 km2 (1973) to 37 km2 (2019). Major features in LUCC are attributed to rapid population growth, resource exploitation, agriculture intensification, economic development, and frequent forest fires. Under a pronounced climate warming, these drivers have been accelerating the degradation of permafrost, subsequently triggering natural hazards and deteriorating the ecological environment. This study represents a benchmark for sustainable LUCC management in the Hola Basin, Northeast China.

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Women's Agency in Controlling Reproduction in Rural Northeast China

PsycEXTRA Dataset ◽

10.1037/e645692011-001 ◽

2010 ◽

Author(s):

Lihong Shi

Keyword(s):

Northeast China ◽

Women's Agency ◽

Women’S Agency

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Review for "Petrology, geochemistry, and zircon U-Pb isotopes of Xintian Complex in Yanbian area, Northeast China: Evidence for magma mixing and geodynamics processes"

10.1002/gj.3749/v1/review1 ◽

2019 ◽

Keyword(s):

Northeast China ◽

Magma Mixing ◽

Pb Isotopes

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Beetles sniff out forest fires

Nature ◽

10.1038/news990325-2 ◽

1999 ◽

Author(s):

Henry Gee

Keyword(s):

Forest Fires

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Assessment of viral assemblages in different types of wetland water in northeast China using RAPD-PCR

Aquatic Microbial Ecology ◽

10.3354/ame01952 ◽

2020 ◽

Vol 85 ◽

pp. 183-196

Author(s):

Y Sun ◽

J Liu ◽

Q Yao ◽

J Jin ◽

X Liu ◽

...

Keyword(s):

Bacterial Community ◽

Water Samples ◽

Northeast China ◽

Bacterial Community Composition ◽

Freshwater Wetlands ◽

Viral Community ◽

Rapd Pcr ◽

Wetland Water ◽

Different Types ◽

Viral Communities

Viruses are the most abundant and ubiquitous biological entities in various ecosystems, yet few investigations of viral communities in wetlands have been performed. To address this data gap, water samples from 6 wetlands were randomly collected across northeast China; viruses in the water were concentrated by sequential tangential flow filtration, and viral communities were assessed through randomly amplified polymorphic DNA-PCR (RAPD-PCR) with 4 decamer oligonucleotide primers. Principal coordinate analysis and hierarchical clustering analysis of the DNA fingerprints showed that viral community compositions differed among the water samples: communities in the 2 coastal wetlands were more similar to each other than to those in the 4 freshwater wetlands. The Shannon-Weaver index (H) and evenness index (E) of the RAPD-PCR fingerprint also differed among the 6 wetlands. Mantel test revealed that the changes in viral communities in wetland water were most closely related to the water NH4+-N and inorganic C content, followed by total K, P, C and NO3--N. DNA sequence analysis of the excised bands revealed that viruses accounted for ~40% of all sequences. Among the hit viral homologs, the majority belonged to the Microviridae. Moreover, variance partitioning analysis showed that the viral community contributed 24.58% while environmental factors explained 30.56% of the bacterial community variation, indicating that the bacterial community composition was strongly affected by both viral community and water variables. This work provides an initial outline of the viral communities from different types of wetlands in northeast China and improves our understanding of the viral diversity in these ecosystems.

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