Spatiotemporal Evolution Analysis and Future Scenario Prediction of Rocky Desertification in a Subtropical Karst Region

Landscape change is a dynamic feature of landscape structure and function over time which is usually affected by natural and human factors. The evolution of rocky desertification is a typical landscape change that directly affects ecological environment governance and sustainable development. Guizhou is one of the most typical subtropical karst landform areas in the world. Its special karst rocky desertification phenomenon is an important factor affecting the ecological environment and limiting sustainable development. In this paper, remote sensing imagery and machine learning methods are utilized to model and analyze the spatiotemporal variation of rocky desertification in Guizhou. Based on an improved CA-Markov model, rocky desertification scenarios in the next 30 years are predicted, providing data support for exploration of the evolution rule of rocky desertification in subtropical karst areas and for effective management. The specific results are as follows: (1) Based on the dynamic degree, transfer matrix, evolution intensity, and speed, the temporal and spatial evolution of rocky desertification in Guizhou from 2001 to 2020 was analyzed. It was found that the proportion of no rocky desertification (NRD) areas increased from 48.86% to 63.53% over this period. Potential rocky desertification (PRD), light rocky desertification (LRD), middle rocky desertification (MRD), and severe rocky desertification (SRD) continued to improve, with the improvement showing an accelerating trend after 2010. (2) An improved CA-Markov model was used to predict the future rocky desertification scenario; compared to the traditional CA-Markov model, the Lee–Sallee index increased from 0.681 to 0.723, and figure of merit (FOM) increased from 0.459 to 0.530. The conclusions of this paper are as follows: (1) From 2001 to 2020, the evolution speed of PRD was the fastest, while that of SRD was the slowest. Rocky desertification control should not only focus on areas with serious rocky desertification, but also prevent transformation from NRD to PRD. (2) Rocky desertification will continue to improve over the next 30 years. Possible deterioration areas are concentrated in high-altitude areas, such as the south of Bijie and the east of Liupanshui.

Research Progress on Illicium difengpi (Illiciaceae): A Review

Illicium difengpi K.I.B. et K.I.M. is a member of the Illiciaceae family with a yet not fully explored utilization value. To provide references for the systematic understanding of I. difengpi (Illiciaceae), the morphological and structural characteristics, wild resource distribution, chemical compounds, pharmacological effects, utilization, and protective measures of this species are reviewed. We conclude that (i) I. difengpi (Illiciaceae) is an endemic and indigenous medicinal species that has been used to treat rheumatoid arthritis and traumatic injury in China; (ii) I. difengpi (Illiciaceae) can endure various abiotic stresses, especially extreme drought, and thus has scientific value for exploring adaptive mechanisms of tolerance to extreme drought and in the ecological restoration of karst rocky desertification areas; and (iii) the beautiful tree shapes of I. difengpi (Illiciaceae) give it potential ornamental value. However, the wild resources of I. difengpi (Illiciaceae) have rapidly decreased, and there is an urgent need to protect this endangered species to maintain its diversity. Protection measures include the protection of wild germplasm resources, the establishment of an I. difengpi (Illiciaceae) germplasm resource bank, and the development of large-scale ecological planting techniques. In further research, the medicinal and scientific value of I. difengpi (Illiciaceae) should be systematically explored to clarify the plant’s effective pharmaceutical value, clinical applications, mechanisms of drought adaptation, and genetic diversity.

Influence of Drought Stress and Rehydration on Moisture and Photosynthetic Physiological Changes in Three Epilithic Moss Species in Areas of Karst Rocky Desertification

The drought resistance mechanism of typical mosses in the karst area was studied, and the water and photosynthetic physiological adaptation of mosses to karst environmental change was analyzed in this paper, which provided the basis for the restoration and control of karst rocky desertification ecological environment. Three superior plants in the rocky desertification area of Guizhou province were selected; they are, respectively, Erythrodontium julaceum (Schwaegr.) Par., Barbula unguiculata Hedw., and Bryum argenteum Hedw. Results show that the three kinds of plant rock mosses of leaf water potential (Ψs), free water content ( V a ), total water content, and relative water content (RWC) decreased; bound water ( V s ), water saturation deficit (WSD), and V s / V a ratio increased; transpiration rate (Tr) fell slightly, under drought stress. The physiological indexes of water have different degrees of recovery after rehydration. The total chlorophyll content shows a trend of first increasing followed by falling and then rising. RWC was negatively related to qN and positively related to F v / F m , yield, ETR, and qP. After rewetting, the fluorescence parameters are returned to average level under mild-to-moderate stress. At the same time, it is hard to get back to the control level under severe pressure. The water use efficiency (WUE) decreased with stress and recovered to different degrees after rehydration.

The Effects of Vegetation Restoration and Season On Soil Enzyme Activity and Microbial Communities in Karst Rocky Desertification Area

Aims The process of karst rocky desertification has been closely related to improper land use in southwest China. Now this habitat is the subject of an important ecological restoration project. However, the changes in soil properties and microbial characteristics in response to this vegetation restoration remain poorly understood.Methods We investigated four vegetation types, including dragon fruit, Chinese pepper, walnut teak, with corn as a control, in southwest China, in 2019. We measured the impacts of these vegetation types on soil properties and microbial biomass, enzyme activity, and microbial community composition (using high-throughput sequencing technology).Results The different vegetation types had significantly different impacts on soil exchangeable Ca2+, soil organic carbon and available nutrients. The vegetation types also significantly affected microbial biomass. Soil enzyme activity, including b-1,4-glucosidase, b-1,4-N-acetylglucosaminidase, alkaline phosphatase, and catalase, were significantly different among vegetation types. All vegetation types were dominated by the bacterial phyla Acidobacteria, Proteobacteria, and Actinobacteria and the fungal phylum Ascomycota, except for corn which was dominated by the fungal phylum Mucoromycota. Non-metric multidimensional scaling (NMDS) showed that the vegetation type exhibited different microbial b-diversity, especially in winter. The vegetation type, season, and soil properties collectively explained 46% and 59% of soil bacterial and fungal community composition, respectively. The bacterial-fungal interactions under the six vegetation types were distinctly different between summer and winter.Conclusions Compared with traditional corn, the restoration of natural vegetation partially reversed KRD by improving soil properties, increasing microbial biomass, and differentiating the microbial community structures in the different vegetation types.