Vegetation Improves Hydro‐Mechanical Soil Resilience on Humid Tropical Slopes: Field Evidence for Sustainable Land Management

Landslides represent a recurring hazard in humid tropical regions, primarily driven by intense rainfall that weakens slope materials and reduces shear resistance. Vegetation is widely promoted as a nature‐based solution to improve near‐surface soil conditions; however, systematic field‐based hydro‐mechanical evidence from humid tropical environments remains limited. It was hypothesised that vegetation cover enhances soil mechanical resistance and regulates hydrological behaviour compared to bare slopes. Therefore, this study investigates the effects of vegetation on soil shear strength, moisture content and percolation rate across seven representative slopes within the Universiti Malaya campus, providing a comparative field‐based assessment of vegetated and bare slopes under humid tropical conditions. Paired sampling of bare and vegetated slopes was conducted biweekly for 6 cycles, and all measurements were analysed using a t ‐test and two‐way ANOVA to assess statistical significance. Results revealed that vegetated slopes exhibited a 17.7% increase in mean shear strength (40.11 ± 5.03 kPa) and a 21.1% higher soil moisture content (21.99% ± 5.80%) compared to bare slopes (33.94 ± 5.87 kPa and 18.15% ± 4.92%, respectively; p < 0.05). In contrast, soil percolation rates decreased slightly (~11%), but this decrease was not statistically significant ( p = 0.17). Soil water content at 0–15 cm under shrub‐ and tree‐covered slopes was comparable to that on bare slopes, whereas vegetated slopes exhibited lower soil saturation and greater soil field capacity across soil depths. These findings demonstrate the role of vegetation as a nature‐based solution for reducing soil degradation and enhancing slope resilience in humid tropical environments.