Biocrust heterogeneity drives water balance in the topsoil of temperate sandy post-mining ecosystem

Abstract Purpose Sandy habitats in temperate regions include a range of anthropogenic and semi-natural ecosystems, such as post-mining areas. Such environments face severe ecological constraints due to coarse soil texture, low nutrient content, and poor water retention. Among natural recovery processes, biological soil crusts (biocrusts) play a key role in shaping soil hydrology and surface stability. Methods In this study, we investigated water-related traits and functional parameters of three biocrust types: algae-, moss-, and lichen-dominated, developing in temperate sandy post-mining ecosystem. Results Our findings revealed significant ecohydrological differences between biocrusts dominated by various photoautotrophs. Lichen-dominated biocrusts showed high water-holding capacity (145.93%), vapor adsorption (0.197 mm) and evaporation cumulative amounts (4.768 mm), together with elevated dehydrogenase activity (284.23 µg TPF g − 1 DW), total exopolysaccharide concentration (3.83 mg g − 1 DW) and total chlorophyll content (156.63 µg g − 1 DW). Their high evaporation rate (0.984 mm h⁻¹) may intensify short-term water fluctuations in sandy topsoils. In contrast, algae-dominated biocrusts showed consistently low values across studied water-related traits (e.g. vapor adsorption 0.02 mm), as well as low evaporation rate (0.294 mm h − 1 ) indicating prolonged surface moisture retention. Moss-dominated biocrusts showed moderate vapor adsorption (0.051 mm) and intermediate evaporation (0.859 mm h⁻¹), offering a more balanced hydrological profile. Conclusions Our findings showed that different biocrust types spontaneously developing in post-mining sandy ecosystem contribute to maintaining the heterogeneity of the topsoil in terms of water holding capacity and the ability to absorb and evaporate water. This functional heterogeneity can help stabilize soil water dynamics, mitigate extreme fluctuations, and support more resilient vegetation development over time, and may be key to enhancing ecosystem resilience in temperate sandy soils.