Research Progress of Grassland Ecosystem Structure and Stability and Inspiration for Improving Its Service Capacity in the Karst Desertification Control

Abstract

The structure and stability of grassland ecosystems have a significant impact on biodiversity, material cycling and productivity for ecosystem services. However, the issue of the structure and stability of grassland ecosystems has not been systematically reviewed. Based on the Web of Science (WOS) and China National Knowledge Infrastructure (CNKI) databases, we used the systematic-review method and screened 133 papers to describe and analyze the frontiers of research into the structure and stability of grassland ecosystems. The research results showed that: (1) The number of articles about the structure and stability of grassland ecosystems is gradually increasing, and the research themes are becoming increasingly diverse. (2) There is a high degree of consistency between the study area and the spatial distribution of grassland. (3) Based on the changes in ecosystem patterns and their interrelationships with ecosystem processes, we reviewed the research progress and landmark results on the structure, stability, structure-stability relationship and their influencing factors of grassland ecosystems; among them, the study of structure is the main research focus (51.12%), followed by the study of the influencing factors of structure and stability (37.57%). (4) Key scientific questions on structural optimization, stability enhancement and harmonizing the relationship between structure and stability are explored. (5) Based on the background of karst desertification control (KDC) and its geographical characteristics, three insights are proposed to optimize the spatial allocation, enhance the stability of grassland for rocky desertification control and coordinate the regulation mechanism of grassland structure and stability. This study provided some references for grassland managers and relevant policy makers to optimize the structure and enhance the stability of grassland ecosystems. It also provided important insights to enhance the service capacity of grassland ecosystems in KDC.

Keywords: ecosystem services; grassland ecosystem; karst desertification control; stability; structure.

Figure 1

Trend in the annual distribution of literature related to the structure and stability of grassland ecosystems (MEA: Millennium Ecosystem Assessment; SDGs: Sustainable Development Goals).

Figure 2

Grassland ecosystem structure and stability research content division. (From left to right, there is the legend of structure studies; structure optimization; stability studies; relationship between structure and stability; and influencing factors of structure and stability).

Figure 3

Artificial grassland planting structure. (a) Forage mono sowing: Grass forage, Lolium perenne L., (b) Pasture intercropping: Grasses-Leguminosae Forage, Lolium perenne L. + Medicago sativa L., Trifolium repens L.+ Lolium perenne L., (c) Pasture mix sowing: Grasses-Leguminosae Forage, Lolium perenne L. + Medicago sativa L., (d) Forage high and low mix sowing: Lolium perenne L. + Medicago sativa L. + Trifolium repens L. + Lolium perenne L. (The grass species of (b–d) are the same, but the arrangement of planting order is different. (b,c) are planted in a horizontal way, but the density and proportion of planting are different. (b) is good for personnel to manage, and (c) is good for the nutrient complementation of grass species. (d) is planted in a vertical way, which can fully utilize light, heat, water and air).

Figure 4

The structural components of grassland ecosystems and the factors that influence them combine to influence grassland ecosystem stability.

Figure 5

The flow diagram showing the steps of the methodology and selection process used for the systematic literature review on the left and the literature review process on the right.

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).