Agroforestry Ecosystem Structure and the Stability Improvement Strategy in Control of Karst Desertification

Abstract

Agroforestry systems (AFS) are priority semi-natural ecosystems in fragile ecological zones. The complexity and diversity of their species structure play a crucial role in maintaining AFS stability. To explore the optimization of improvement strategies in AFS’ structure and stability for control of karst desertification (KD), in this study, we chose typical desertification control areas in the southern China karst region. The study included homegarden (HG), agrisilviculture (ASV), and multipurpose woodlots (MWLs) as three AFS. We quantified the AFS’ structural characteristics using descriptive statistics and spatial structure parameters. We used the fuzzy integrated evaluation method with structural and functional indicators as guidelines, and stand structure, plant species diversity, soil fertility, and environmental factors as first-level evaluation indicators. The entropy weight method calculates the weights of indicators at all levels. The fuzzy comprehensive evaluation method establishes an evaluation index system to evaluate the grading of AFS’ stability. The results showed that: (i) The species composition of the AFS in the KD control areas had a simple structure, the overall diversity level was low, and the diversity level of herbaceous plants was better than that of woody plants. (ii) The overall distribution curves of diameter at breast height (DBH), tree height (TH), and crown width (CW) of woody plants in the AFS in the KD control areas were slight to the left, with a single-peaked pattern, mostly randomly and unevenly distributed in space, with a low degree of tree species isolation and relatively weak stand stability. (iii) There was variability in the stability classes of different types of AFS, overall reflecting the ranking HG > ASV > MWLs. (iv) When structural optimization was applied, corresponding measures can be taken according to farmers’ wishes for different types of AFS and their primary business purposes. The improvement of stability depends mainly on the utility of the structural optimization applied coupled with positive human interference (for example, pruning, dwarfing, and dense planting). This study provides a scientific reference for maintaining the stability of AFS and promoting service provision.

A New Advance on the Improvement of Forest Ecosystem Functions in the Karst Desertification Control

“…This is not only an important means to support the mutually beneficial coexistence of species, but also an important measure to maintain system stability and enrich diversity. Jiang et al [18] constructed a stability evaluation system based on forest structure and functional indicators using a comprehensive evaluation method, and found a positive correlation between stability and biodiversity, while also identifying the subjective wishes of farmers. In summary, optimizing the species structure of forest stands is an important means toward improving the nutritional structure of ecosystems and enhancing their stability; it also acts as an important foundation on which to enhance ecosystem functions, therefore promoting ecological restoration in desertification areas.…”

“…Under the strong intervention of ecological restoration projects, rapid vegetation restoration has led to the dilemma of regional ecosystem singularity, biodiversity decline, and functional deterioration. With the increasing awareness of the inseparable relationship between the quality of the ecological environment and the development of economic health, understanding how the effects of niche and forest type combinations affect system structure and stability is the key to improving regional landscape functions [17,18]. In the future, it is necessary to continue to enhance the cultivation of forest species and the study of the inherent relationships between inter-species material circulation, energy flow, and information transmission in the ecosystem process, in order to improve the overall resilience of the ecosystem.…”