Micro-Environmental Variation in Soil Microbial Biodiversity in Forest Frontier Ecosystems—Implications for Sustainability Assessments

VALERIA ESTHERÁLVAREZ; VERÓNICA ANDREA EL MUJTAR; JOANA FALCÃO SALLES; XIU JIA; ELISA CASTÁN; ANDREA GABRIELA CARDOZO; PABLO ADRIÁN TITTONELL

Sustainability (Switzerland)

Multidisciplinary Digital Publishing Institute (MDPI)

Año: 2024 vol. 16

Soil health indicators based on microbial biodiversity are increasingly used in agriculturalsustainability assessments. However, little is known about how microbial communities vary withinmicro-environmental gradients across different land uses, which is crucial for designing field samplingand monitoring protocols. Our objective was to assess how soil microbial communities changedwith soil depth and spatial distance across land-use types. We sampled soils in four spatial distances(within 0.1–70 m) and four depths (within 0–40 cm) in forests, grasslands, and horticultural lands,and combined 16S rRNA gene sequencing, DNA quantification and soil chemical characterizationto explore micro-environmental variation in microbial biomass,α-β-diversity, and communities’assembly processes. Depth and spatial distance had differential effects on microbial biodiversitywithin different land uses. Microbial biomass was most sensitive to depth,α-diversity to spatialdistance, andβ-diversity to both depth and spatial distance. Deterministic processes dominatemicrobial communities’ assembly along depth in all land uses, which is a promising result fordeveloping soil quality indicators based on microbial biodiversity. Overall, our results suggestthat collecting soil samples separated by at least 12 m is adequate to capture biodiversity changesacross land uses. However, collecting randomly within the first 10 cm is recommended for nativeforests, while systematic sampling within the first 20 cm is advised for grasslands and horticulturallands. Our findings underscore the need for land use-specific sampling frameworks in soil life-basedsustainability assessments for meaningful regional comparisons.