Cellulose and lignin decomposition is crucial for efficient nutrient cycling, yet few studies have been performed regarding the effects of soil fauna on cellulose and lignin decomposition. This study was conducted to better understand the effects of soil fauna on lignin and cellulose decomposition in the Changbai Mountain. Litterbags of two different mesh sizes were used to examine cellulose and lignin decomposition of 11 species of plant litter in the four vegetation zones of the Changbai Mountain North Slope over a 24-mo period. Cellulose and lignin clearly declined over time for all 11 species of plant litter. Cellulose decomposition rate faster than the rate of lignin decomposition in the majority of plant species. Soil fauna could promote the decomposition of cellulose and lignin. The abundance and richness of soil fauna in coniferous broad-leaved mixed forests were greater than in coniferous forest, Betula ermanii Cham. (Fagales: Betulaceae) forest, and alpine tundra. Soil fauna had a greater effect on Abies nephrolepis Maxim. (Pinales: Pinaceae) cellulose and lignin, whereas contribution rates were relatively lower in the Fraxinus mandshurica Rupr. (Contortae: Oleaceae) and Acer mono Maxim. (Sapindales: Aceraceae) litterbags at the end of the experiment. Litter quality was negatively correlated with the soil faunal contribution to litter decomposition directly. Overall, the findings of this study have implications for the effects of soil fauna on cellulose and lignin decomposition in the alpine ecosystem, and also can provide experimental evidence that soil faunal contribution is affected by soil faunal communities and litter quality.

Drastic land pattern change has taken place in the northeast region of China, which may have a significant impact on landscape and ecosystem service. Up to now, insufficient renewal of land use patterns may limit the latest assessment of landscape transition and ecosystem service value. Meanwhile, the adaptive ecosystem service value improvement method should be established. To solve this issue, the integrated methodology of land-use change monitoring—landscape analysis—the promoted ecosystem service measurement is established. Results show that: (1) New evidence is observed that the cultivated land in Northeast China has been reduced, with 309,610.33 km² in 2010 and 309,417.52 km² in 2020, showing a net change area of −192.82 km². This is the opposite of the increase of cultivated land compared to the past. (2) Shannon’s diversity index displays an upward trend, with the richer landscape types and higher fragmentation in the whole region. In addition, the contagion index reduced, with a total decrease of 1.93, indicating that the patches distribute intermittently and the agglomeration degree of these patches is weakened. (3) More precise ecosystem service value is assessed, from 2868.39 billion yuan in 2000 to 2814.06 billion yuan in 2020, and the hydrological regulation, climate regulation, and soil conservation play a dominant role in these functions in 2020. The spatial pattern of ecosystem service value is high-rank in the Northwest and Southeast, and low-rank in other directions. This study provides the new results on land change and landscape pattern and creates an improved ecosystem service value assessment method in Northeast China, to provide a more suitable ecosystem assessment application for Northeast China.

The harsh environmental conditions in alpine tundra exert a significant influence on soil macro-arthropod communities, yet few studies have been performed regarding the effects of vegetation heterogeneity on these communities. In order to better understand this question, a total of 96 soil macro-arthropod samples were collected from four habitats in the Changbai Mountains in China, namely, the Vaccinium uliginosum habitat, Sanguisorba sitchensis habitat, Rhododendron aureum habitat, and Deyeuxia angustifolia habitat. The results revealed that the taxonomic composition of the soil macro-arthropods varied among the habitats, and that dissimilarities existed in these communities. The abundance, richness and diversity in the D. angustifolia habitat were all at their maximum during the sampling period. The vegetation heterogeneity affected the different taxa of the soil macro-arthropods at various levels. In addition, the vegetation heterogeneity had direct effects not only on soil macro-arthropod communities, but also indirectly impacted the abundance, richness and diversity by altering the soil fertility and soil texture. Overall, our results provide experimental evidence that vegetation heterogeneity can promote the abundance, richness and diversity of soil macro-arthropods, yet the responses of soil macro-arthropods to vegetation heterogeneity differed among their taxa.

Land degradation in black soil regions has a significant effect on belowground systems, and Collembolans can adequately indicate environmental changes in the soil. However, there is currently a knowledge gap in the literature regarding the responses of soil Collembolans to land degradation. In order to better understand this issue, in this study, a total of 180 soil Collembolan samples were collected from four habitats with varying degrees of land degradation in the Songnen Plain, namely a no land-degradation habitat (NLD), light land-degradation habitat (LLD), moderate land-degradation habitat (MLD) and severe land-degradation habitat (SLD). The results reveal that the different degrees of land degradation caused some differences in the taxonomic composition of the Collembolans; however, the majority of the Collembolan species are distributed relatively evenly. Proisotoma minima are always a dominant species during the study period. Seasonal variations are observed in the abundance, richness and diversity levels. In the severe land-degradation habitats (SLD), the abundance, richness, diversity and community complexity of the Collembolans are aways at the lowest levels. In addition, Proisotoma minima is negatively correlated with a majority of the species of Collembolans in the low levels of the land-degradation habitats, whereas they are positively correlated with most of the other species in the high levels. Epedaphic and euedaphic Collembolans responded to land degradation more obviously. The structural equation model (SEM) displays that soil Collembolan communities respond negatively to land degradation. Overall, our results provide implications that soil Collembolan communities are affected by land degradation, and that different taxa of soil Collembolans respond to degradation in numerous ways.