Adequate Understanding of Ecosystem Structure Optimization Is a Necessary Prerequisite for the Improvement of Ecosystem Services in Grasslands for the KDC

Although existing pasture cultivation has greatly increased forage production in the short term [239], it has made an outstanding contribution to KDC. However, the factors influencing the improvement of ecosystem services are not only determined by a single factor of production stability, and there is an urgent need to improve grassland ecosystem services through a variety of specific ways. Grassland ecosystem structure directly determines grassland ecosystem function and indirectly influences grassland ecosystem services. Research on multi-component mixes of legume grasses with different growth habits or morphological characteristics has concluded that the greater the number of components in the mix, the greater the likelihood of containing key species, and the greater the potential for community stability, thus achieving a seasonal balance in grassland output throughout the year and lasting stability in the number of years of use [240]. Similar experiments have been conducted in KDC areas, for example, the state replanted degraded grasslands with *Trifolium repens* L. and encouraged farmers to plant *Trifolium repens* L.+ *Lolium perenne* L. or *Dactylis glomerata* L. + *Medicago sativa* L. and other measures, which improved the ecosystem structure of grasslands of KDC to some extent. However, with the unique geographical environment of karst, seasonal drought and unreasonable human management, the ecological benefits of degraded and improved grasslands have gradually decreased [241]. Therefore, the following two points should be considered to enhance the service capacity of grassland ecosystems: (1) to optimize the planting structure of grassland ecosystems for rocky desertification management and enrich the spatial species composition of grassland, and to select stony, drought-tolerant and calcium-loving grasses for planting in response to the characteristics of karst desertification such as thin soil layers, easy soil erosion and calcareous lithology; and (2) strengthening research on the benefits of the structure–process–function–services cascade, so as to clarify the process of maintaining ecosystem productivity and stability [95].
