With progress in biogeomorphology, there is growing recognition that organisms, the so-called ‘ecosystem engineers’, can actively modify their habitat conditions, consequently shaping overall landscapes in various natural systems. However, understanding the role of a single ecosystem engineer may not be sufficient to fully explain landscape or landform dynamics. These biogenic landscapes are possibly outcomes of the cumulative effects of several reciprocally interacting ecosystem engineer species. There is still much room to explore their combined effect on landform changes at short and long time scales. This study attempted to quantitatively investigate the interaction between two typical ecosystem engineers in salt marshes: Suaeda maritima and crabs. Our findings revealed that crab bioturbation was significantly denser near the plants than in the surrounding bare ground soil. Furthermore, the result of correlation analysis indicated that the larger the individuals of Suaeda maritima, the more intensive was bioturbation. By examining several soil properties, we found significant differences between crab chimneys and bare ground soils regarding mean grain size. Finally, variance component analysis results showed that the sampling unit, which separates crab chimneys from bare ground soils, can partially explain soil physical conditions. Mutually interacting engineer species and their bioturbation can account for spatial variations of soil properties, thereby suggesting the possibility of understanding soils as an outcome of combined ecosystem engineering in salt marshes.