The expansion of life into estuaries, streams and their adjoining landscapes generated a positive feedback loop in which the environment became less harsh, more stable and thus more hospitable to life. One of the major aspects of this feedback loop was the enhanced weathering of soils caused by plants and their associated fungi. This enhanced weathering resulted in the reduction of soil particle sizes and the increased leaching of plant and microbial nutrients. Moreover, accumulations of plant organic matter, combined with the increased proportion of finer soil particles, increased the soils capacity to store water. Improved water storage would have reduced erosion and moderated water flows in streams and estuaries.
Flooding becomes less destructive and more beneficial.
The combination of more moderate flows and increasingly dense stands of trachaeophytes would have stabilized the banks of streams and estuaries. Increased bank stability, combined with inputs of fine sediments, would in turn stabilize shallow water habitats and engendered the development of wetlands. The growth of vascular plants in and adjacent to the shallow waters and wetland habitats along the margins would have provided an important source of organic matter to aquatic animals in streams and estuaries. Shallow waters and wetlands are commonly the most productive of modern day ecosystems. Their debut during the Devonian Transformation may have paved the way for the evolution of tetrapods.