Assessing Soil Biodiversity Potentials in China: A Multi-Attribute Decision Approach

Abstract

Habitat for biodiversity is a crucial soil function. When assessed at large spatial scales, subjective assessment models are usually constructed by integrating expert knowledge to estimate soil biodiversity potentials (SBP) and predict their trends. However, these regional evaluation methods are challenging to apply mechanistically to other regions, especially in China, where soil biodiversity surveys are still in their infancy. Taking China (9.6 × 106 km2) as the study area, we constructed a Decision EXpert (DEX) multi-attribute decision model based on abiotic factors from soil and climate data that are known to be relevant for the habitat of soil biota. It was used to indirectly assess and map national SBP based on the habitat suitability for fungi, bacteria, nematodes, and earthworms in the topsoil. The results show: (1) the SBP in China was classified into five grades: low, covering 19.8% of the area, medium-low (21.2%), medium (16.0%), medium-high (38.5%), and high (4.5%); (2) the national SBP is at a moderate level, with hotspot areas (1.3 × 106 km2) located in the Yangtze Plain Region, the southeastern Southwest China Region, and the central-eastern South China Region; while the coldspot areas (2.6 × 106 km2) are located in the Gansu–Xinjiang Region and the northeastern Qinghai–Tibet Region; (3) Soil (pH, SOC, CEC, texture, total P, and C/N ratio) and climate (arid/humid regions, temperature zones) were identified as driving this SBP variation. This study presents a general approach to describing soil habitat function on a broad scale based on environmental covariates. It provides a systematic basis for selecting indicators and maps them to SBP from an objective perspective. This approach can be applied to regions where no soil organism survey is available and can also serve as a pre-survey for planning soil resource utilization and conservation.