Research progress on ecology and sustainable development of Guilin Lijiang River Basin, China, based on bibliometric analysis.

Guilin is a typical representative of karst landform in South China. Because of its unique geographical landform and hydrological environment, Lijiang River Basin has received a certain degree of attention in field of ecology and sustainable development. Explore and visualize the hotspots and frontiers of Guilin Lijiang River Basin Ecology and Sustainable Development (GLRBESD) by using bibliometrics, CiteSpace, and VOSviewer. Results showed that number of published papers was in a fluctuating upward trend from 1992 to 2022 and from 2011 to 2022, respectively. Work of scholars in this field has been continuously strengthened and deepened, and overall scientific research results show an increasing trend. Research objects and topics are mainly aimed at the water resources, climate, and environment of GLRB Landscape ecology and SDG index construction. Research of GLRBESD-published documents has the characteristics of multi-disciplinary and interdisciplinary integration. High-frequency keywords in research field focus on ecotourism, ecological restoration, and sustainable development, mainly based on the research of ecotourism development. Impact of environmental factor changes and human activities on land use change in different periods is an important research topic. Core research field of GLRBESD on macro-scale can be divided into ESV and function, ecological compensation and ecotourism, ecological environment and ecological restoration, ecological network and ecological risk assessment, and sustainable development. This research provides systematic scientific research basis for enhancing sustainable development ability and ecosystem functions and services of World Natural Heritage Site.

Spatio-Temporal Evolution and Influence Mechanism of Habitat Quality in Guilin City, China.

Based on the models of ArcGIS10.5, Fragstats 4.2, and InVEST, this research describes the temporal and spatial evolution characteristics of habitat quality in Guilin from three aspects, which are land use change, landscape pattern change, and habitat quality evaluation, and further explores the main driving factors of Guilin's habitat quality change by using the method of geographic detector evaluation. The results indicate that from 2000 to 2020, the land use type in Guilin City is dominated by forest, accounting for the highest proportion of 77.87%. The forest has decreased significantly, the mutual transformation of forest and cropland is obvious, and the area of impervious has continued to increase. A large amount of cropland is occupied, indicating that human activities were the main factor in land use transformation. From 2000 to 2020, the irregularity of the patch shape of each land use type was deepened, the fragmentation degree was relatively stable, the landscape diversity was enhanced, and the spatial distribution of each patch showed a relatively obvious heterogeneity. From 2000 to 2020, the habitat quality of Guilin City was mainly high-grade and the habitat quality was good, but the overall trend showed a downward trend, and the spatial difference was obvious. From 2000 to 2020, elevation, normalized difference vegetation index (NDVI), splitting index (SPLIT), and slope were the main factors affecting the habitat quality of Guilin City, among which elevation and NDVI had the most significant effects.

[Impact of microbial aggregating agents on soil aggregate stability under addition of exogenous nutrients].

In this study, we investigated the effects of biological aggregating agents (fungal hyphae and microbial extracellular polysaccharides) soil aggregate (with different sizes) stability under addition of exogenous nutrients. The exogenous nutrients included glucose and ammonium nitrate. Experiments were conducted in a 30 d incubation period with three treatments: (1) the control (0.5 mg x g(-1) soil); (2) CN5 (0.5 mg x g(-1) soil, 0.1 mg x g(-1) soil, C/N = 5); (3) CN10 (0.5 mg x g(-1) soil, 0.05 mg x g(-1) soil, C/N = 10). Results showed that soil respiration rates were not significantly different among the three treatments, with maximums being about 3.10 mg x (h x kg)(-1), indicating that the impact of inorganic nitrogen fertilizer was not obvious in a short term. Aside from 5 d, macroaggregates amount of CK (15.67%) was observably lower than those of CN5 (25.32%) and CN10 (24.63%), there were no remarkable discrepancies among 3 treatments in other incubation period. The insignificant difference in the aggregate amounts among the three treatments suggested that the influence of glucose on microbial activities surpassed the inorganic nitrogen fertilizer in shortterm in the study.