Evaluating the Impact of Near-Natural Restoration Strategies on the Ecological Restoration of Landslide-Affected Areas Across Different Time Periods

Abstract

Landslides are a common geological hazard in mountainous areas, causing significant damage to ecosystems and production activities. Near-natural ecological restoration is considered an effective strategy for post-landslide recovery. To investigate the impact of near-natural restoration strategies on the recovery of plant communities and soil in landslide-affected areas, we selected landslide plots in Lantian County at 1, 6, and 11 years post-landslide as study sites, surveyed plots undergoing near-natural restoration and adjacent undisturbed control plots (CK), and collected and analyzed data on plant communities and soil properties. The results indicate that vegetation succession followed a path from "human intervention to natural competition": species richness peaked at 1 year post-landslide (D_m = 4.2). By 11 years, dominant species prevailed, with tree species decreasing to 4.1 ± 0.3, while herbaceous diversity increased by 200% (from 4 to 12 species). Soil recovery showed significant temporal effects: total nitrogen (TN) and dehydrogenase activity (DHA) exhibited the greatest increases after 1 year post-landslide (132% and 232%, respectively), and by 11 years, the available nitrogen (AN) in restored plots recovered to 98% of the CK levels. Correlations between plant and soil characteristics strengthened over time: at 1 year, only 6-9 pairs showed significant correlations (p < 0.05), increasing to 21-23 pairs at 11 years. Near-natural restoration drives system recovery through the "selection of native species via competition and activation of microbial functional groups". The 6-11-year period post-landslide is a critical window for structural optimization, and we recommend phased dynamic regulation to balance biodiversity and ecological functions.

Keywords: ecological succession; landslide; restoration strategies; soil properties; vegetation characteristics.

Figure 1

Research scope map. (a) The location of Shaanxi Province in China. (b) Lantian County’s location in Shaanxi Province. (c) The study area and unaffected study area’s location in Lantian County.

Figure 2

Sampled plot arrangement plan. (a) Landslide site diagram. Layout of the plots: (1) upper slope; (2) middle slope; (3) lower slope. In (b), I, II, and III represent three 10 m × 10 m tree plots, while the sizes of the other plots can be referred to in the legend.

Figure 3

Alpha diversity of plant community species. (A–C) represent plots affected by landslide events in 2021, 2016, and 2011, respectively. Plots surveyed in 2022 are abbreviated as N, and those surveyed in 2023 as NN. N (CK) and NN (CK) denote respective control plots.

Figure 4

Changes in functional traits of plant communities. Plots 1, 2, and 3 represent areas affected by landslide events in 2021, 2016, and 2011, respectively. N denotes plots sampled in 2022, NN denotes plots sampled in 2023, and CK represents control plots, indicating undisturbed areas without landslides. (A) is the number of species in the community; (B) is the height of the plant; (C) is the diameter at breast height of the plant; (D) is the density of the plant; (E) is the leaf area; (F) is the leaf length; (G) is the leaf width; and (H) is the leaf thickness.

Figure 5

Changes in soil properties in landslide sample sites. Plots 1, 2, and 3 represent areas affected by landslide events in 2021, 2016, and 2011, respectively. N denotes plots sampled in 2022, NN denotes plots sampled in 2023, and CK represents control plots, indicating undisturbed areas without landslides. (A) is the total nitrogen content; (B) is the available nitrogen content; (C) is the total phosphorus content; (D) is the effective phosphorus content; (E) is the total potassium content; (F) is the effective potassium content; (G) is the cation exchange capacity; (H) is the sucrase content; (I) is the phosphatase content; (J) is the urease content; (K) is the protease content; and (L) is the dehydrogenase content.

Figure 6

Correlations between plant community characteristics and soil physicochemical properties in landslide plots. Plots 1, 2, and 3 represent areas affected by landslide events in 2021, 2016, and 2011, respectively. N denotes plots sampled in 2022, and NN denotes plots sampled in 2023. Plant traits include the following: No. (species number), H (plant height), DBH (diameter at breast height or basal diameter), coverage (canopy closure or layer coverage), LA (leaf area), LL (leaf length), LW (leaf width), and LT (leaf thickness). Soil physicochemical properties include the following: TN (total nitrogen content), AN (available nitrogen content), TP (total phosphorus content), AP (available phosphorus content), TK (total potassium content), AK (available potassium content), CEC (cation exchange capacity), SUC (sucrase activity), PHO (phosphatase activity), UE (urease activity), PRO (protease activity), and DHA (dehydrogenase activity). Significance levels: * p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001.