Assessing Landscape Fragmentation and Soil Disturbance Linked to Road Networks and Proposing Low‐Impact Engineering Solutions

ABSTRACT The rapid expansion of road infrastructure in China, particularly within the ecologically sensitive high‐elevation regions of the Yunnan–Tibet plateau, has emerged as a double‐edged sword for national development. While these networks facilitate economic connectivity and regional integration, they simultaneously impose profound anthropogenic pressures on the surrounding environment. This research provides a novel, integrated assessment of two interconnected threats: landscape fragmentation and geotechnical soil disturbance. Historically, these two phenomena have been studied in isolation; however, this paper argues that the degradation of soil mechanical properties and the bisection of natural habitats are synergetic processes that require a unified engineering response. The mechanistic core of this Eco‐Geotechnical framework lies in what may be termed Rhizosphere‐Substrate Decoupling. The construction‐induced alkalization and carbon depletion do not merely change soil chemistry; they eliminate the glomalin and fungal hyphae that act as biological binding agents for soil aggregates. This loss of biological cohesion creates a feedback loop: the weakened soil substrate cannot support the root architecture of native species, which in turn leads to increased pore‐water pressure and slope failure. Thus, the geotechnical instability of the road shoulder becomes a permanent disturbance barrier that physically prevents the closing of landscape gaps, locking the forest into a state of chronic fragmentation. Utilizing the newly synthesized G214–G219 Integrated Eco‐Geotechnical Dataset (2025), this study employs a multi‐scalar methodology. Landscape fragmentation was quantified using high‐resolution (30 m) Landsat 8 OLI satellite imagery and the integral index of connectivity (IIC). The spatial analysis reveals a critical transformation of the forest matrix into isolated habitat islands, with forest connectivity indices showing a staggering decline of 91.3% in the Lancang River Valley segment. The roadless volume (RV) index indicates that the Road Effect Zone extends 1 km from highways, significantly hindering species movement. A geotechnical study across 25 monitoring stations along the G214 road shows that road construction alters soil properties, increasing pH from 5.5 to 7.2 and reducing Total Carbon and Total Nitrogen, jeopardizing soil productivity. Seasonal changes affect geotechnical stability, with soil strength dropping from 27.5% in dry seasons to 18.9% in wet seasons, raising concerns about road integrity and erosion during monsoons. To address these impacts, the paper suggests low‐impact engineering (LIE) solutions such as cut‐and‐cover tunnels for restoring ecological continuity and bio‐engineered methods like Vetiver grass and biodegradable geotextiles for soil stabilization. The incorporation of bio‐swales for hydrological filtering is also recommended. This research emphasizes the need for an eco‐geotechnical approach in China's infrastructure development, aiming to balance human mobility with ecosystem preservation.