Quantitative study of the multilayer complex structure of shrub-herbage-biocrusts based on structural equation model

Area of Science:

• Ecology
• Remote Sensing
• Geomorphology

Background:

• Shrub-herbage-biocrust communities are vital in arid regions, possessing complex 3D structures.
• Understanding these structures is key to their ecological function and restoration.

Purpose of the Study:

• To quantify the 3D vegetation structure of shrub-herbage-biocrust communities.
• To develop a 3D structure index using structural equation modeling (SEM).
• To identify key indicators of horizontal and vertical structural features.

Main Methods:

• Utilized unmanned aerial vehicle (UAV) and quadrat surveys on the Loess Plateau.
• Screened representative indicators for horizontal (projective coverage) and vertical (height, canopy width) structures.
• Constructed a 3D structure index via SEM, weighting vegetation layers and structural indicators.

Main Results:

• Identified projective coverage (shrub, herbage, biocrust) and shrub/herb height as key indicators.
• Determined vegetation layer importance: herbaceous (0.39) > biocrust (0.36) > shrub (0.25).
• Developed a 3D structure index (0-1) positively correlated with interlaced vegetation coverage, reflecting community complexity.

Conclusions:

• SEM effectively quantifies 3D structural characteristics of these communities.
• The 3D structure index provides methodological support for structure-function research.
• Findings offer a theoretical foundation for ecological restoration in arid environments.