Interaction of landslide spatial patterns and river canyon landforms: Insights into the Three Parallel Rivers Area, southeastern Tibetan Plateau.

The interaction and mechanism of landslide spatial patterns and river canyon landforms are significant for understanding geomorphic evolution in intensive tectonic alpine environments. This study focuses on the Three Parallel Rivers Area (TPRA) in the southeastern Tibetan Plateau encompassing three parallel rivers (the Nujiang, Lancang, and Jinsha Rivers), to examine the synergistic evolution of geomorphic features and landslides. The analysis revealed a pattern of landslide aggregation in the river valley characterized by the sequence Nujiang > Lancang > Jinsha Rivers. This pattern aligns closely with the distribution of geomorphic indices (local relief, surface erosion index, and threshold slope gradient) in the valleys. As local relief, normalized surface erosion index and normalized threshold slope gradient increase, the mean values of normalized landslide area density (NLAD) rise from around 0.11 to 0.39, 0.16 to 0.48, and 0.10 to 0.21, respectively. Concurrently, the mean values of normalized frequency of landslide dams (NFLD) increase from around 0.05 to 0.24, 0.12 to 0.22, and 0.02 to 0.17, respectively. Additionally, knickpoints could induce upstream suppression and downstream promotion of landslides showcasing the feedback of landslides on the valley landscape. Our findings indicate that the landform formation process in the southeastern Tibetan Plateau orogen is intricately linked to a substantial landsliding response and the observed mass movements vividly mirror the landform formation pattern. These results hold potential implications for understanding the dynamic equilibrium between uplift and surface erosion in the region. This study enhances our understanding of the interaction and mechanisms of landslides and valley landforms.

Effects of Fusarium solani on the Growth and Development of Anoplophora glabripennis Larvae.

Anoplophora glabripennis (Asian longhorned beetle) is a wood-boring pest that can inhabit a wide range of healthy deciduous host trees in native and non-native habitats. Lignocellulose degradation plays a major role in the acquisition of nutrients during the growth and development of A. glabripennis larvae. In this study, the lignocellulose degradation capacity of Fusarium solani, a fungal symbiont of A. glabripennis, was investigated in fermentation culture and in four host tree species. The impact of F. solani on larval growth and survival parameters was assessed. Fermentation culture demonstrated continuous and stable production of lignocellulolytic enzymes over the cultivation period. Furthermore, F. solani was able to degrade host tree lignocellulose, as shown by decreased soluble sugar and cellulose contents and an increase in protein content. No significant differences in larval survival were observed in larvae fed with or without F. solani. However, weight and head capsule width were higher in larvae fed on F. solani, and gut lignocellulose activities were elevated in fed larvae. Our results indicate a role for F. solani in the predigestion of lignocellulose during the colonization and parasitic stages of A. glabripennis larval development, and also the F. solani an important symbiotic partner to A. glabripennis, lowering barriers to colonization and development in a range of habitats.