Identifying the Interactions between Grassland Ecosystem Structure and Stability Is an Important Part of Enhancing Grassland Ecosystem Services

This paper showed that most of the literature focuses on multiple factors of the structure and stability of grassland ecosystems, but these studies have mainly focused on unidirectional effects, such as Gschwend et al. and Hu et al. showing that biodiversity can stabilize productivity through different mechanisms, such as the asynchronous responses of species to environmental change and stability [242,243]. What is more, exploring the mutual response mechanisms between grassland planting structures and their productive and ecological stability is an important element in clarifying the effects of current grass seed mixes in KDC and local sustainable development. Xu et al. explored the water–fertilizer coupling mechanism between soil and forage through intercropping in the southern karst region. The experiments proved that a reasonable intercropping system could coordinate the relationship between crops and environment and improve soil nutrients, which made a certain contribution to exploring soil–plant relationships in the grasslands of karst areas and improving the structure and stability of stone desertification grassland ecosystems [244]. However, from the perspective of the interaction mechanism of grassland ecosystem structure and stability, exploration into the changes in the supply of ecosystem service capacity of grassland managed by karst rock desertification is still lacking. Therefore, through field control experiments in the context of KDC, the interaction mechanisms of grassland-ecosystem structure and stability should be clarified in the context of KDC, and the exploration of above-ground-subsurface material flow and nutrient circulation fluency should provide important insights to elucidate the trade offs and synergistic relationships among service flows (Figure 6). areas and improving the structure and stability of stone desertification grassland ecosystems [244]. However, from the perspective of the interaction mechanism of grassland ecosystem structure and stability, exploration into the changes in the supply of ecosystem service capacity of grassland managed by karst rock desertification is still lacking. Therefore, through field control experiments in the context of KDC, the interaction mechanisms of grassland-ecosystem structure and stability should be clarified in the context of KDC, and the exploration of above-ground-subsurface material flow and nutrient circulation fluency should provide important insights to elucidate the trade offs and synergistic relationships among service flows (Figure 6).

Identifying the Interactions between Grassland Ecosystem Structure and Stability Is an

This paper showed that most of the literature focuses on multiple factors of the structure and stability of grassland ecosystems, but these studies have mainly focused on unidirectional effects, such as Gschwend et al. and Hu et al. showing that biodiversity can stabilize productivity through different mechanisms, such as the asynchronous responses of species to environmental change and stability [242,243]. What is more, exploring the mutual response mechanisms between grassland planting structures and their productive and ecological stability is an important element in clarifying the effects of current grass seed mixes in KDC and local sustainable development. Xu et al. explored the water–fertilizer coupling mechanism between soil and forage through intercropping in the southern karst region. The experiments proved that a reasonable intercropping system could coordinate the relationship between crops and environment and improve soil nutrients, which made a certain contribution to exploring soil–plant relationships in the grasslands of karst

*Plants* **2023**, *12*, x 22 of 33

Important Part of Enhancing Grassland Ecosystem Services

**Figure 6.** Processes of energy and service flows in grassland ecosystems (structure affects stability and thus changes the level of function and ultimately service provision). **Figure 6.** Processes of energy and service flows in grassland ecosystems (structure affects stability and thus changes the level of function and ultimately service provision).

#### **5. Conclusions 5. Conclusions**

Based on the WOS and CNKI databases, this study systematically reviewed the research progress of grassland-ecosystem structure and stability, and concluded the following: (1) There is a significant increase in the number of annual publications on the structure and stability of grassland ecosystems, and the research directions and themes are becoming increasingly diverse. The research mainly focuses on revealing the mechanisms influencing species diversity and stability, quantitatively studying the nutrient and productivity of forage grasses, and the regulatory mechanisms of stability. (2) The spatial pattern of the study countries is highly consistent with the spatial distribution Based on the WOS and CNKI databases, this study systematically reviewed the research progress of grassland-ecosystem structure and stability, and concluded the following: (1) There is a significant increase in the number of annual publications on the structure and stability of grassland ecosystems, and the research directions and themes are becoming increasingly diverse. The research mainly focuses on revealing the mechanisms influencing species diversity and stability, quantitatively studying the nutrient and productivity of forage grasses, and the regulatory mechanisms of stability. (2) The spatial pattern of the study countries is highly consistent with the spatial distribution characteristics of grassland ecosystems, mainly dominated by countries with wider grassland areas such as China and the United States. However, the number of national publications in Africa contradicts the distribution pattern of grasslands. (3) The research on the structure and stability of grassland ecosystems focuses on the structural characteristics of grassland ecosystems, structural optimization, ecosystem stability, and the structure–stability relationship and its influencing factors, in which the grassland-ecosystem structure and structure and stability influencing factors are the main research directions (4) The key scientific issues that need to be addressed nowadays were grouped according to whether they addressed structure optimization, stability enhancement, and structure–stability relationship. We should strengthen the multi-perspective exploration of grasslands under different spatial and temporal conditions, to enhance the functional output of grassland ecosystems from optimizing the structure of grassland ecosystems, to enhance the stability of grassland ecosystems, and to form a structure–process–function–services cascade benefit study. Based on the above conclusions, three insights can be provided for the enhancement of grassland ecosystem services in the KDC: (i) fully understanding ecosystem structure optimization is a necessary

prerequisite for karst grassland stability; (ii) enhancing grassland ecosystem stability is an important guarantee for enhancing grassland ecosystem services in KDC; and (iii) clarifying the interaction between grassland ecosystem structure and stability is an important link to enhance grassland ecosystem services.

**Author Contributions:** Conceptualization, S.H.; methodology, S.H.; software, S.H.; validation, S.H.; formal analysis, S.H.; investigation, S.H.; resources, S.H.; data curation, S.H.; writing—original draft preparation, S.H.; writing—review and editing, S.H., K.X., Y.C., S.S., J.F. and C.H.; visualization, S.H.; supervision, K.X.; project administration, K.X. and Y.C.; funding acquisition, K.X. and Y.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Key Project of Science and Technology Program of Guizhou Province (No. 5411 2017 Qiankehe Pingtai Rencai), the China Overseas Expertise Introduction Program for Discipline Innovation (No. D17016) and Natural Science Research Project of Education Department of Guizhou Province [Qianjiaohe KY Zi (2022) 157].

**Data Availability Statement:** Not applicable.

**Acknowledgments:** We would like to thank all the editors for their contributions to this paper and the anonymous reviewers for their thoughtful comments, which enriched the paper.

**Conflicts of Interest:** The authors declare no conflict of interest.
