Urban Soils and Their Potential to Provide Ecosystem Services.

Soils form the foundation for many ecological processes and interactions such as nutrient cycling, distribution of plants and animals, and ultimately location of human habitation.  Although soils in urban and urbanizing landscapes are predominately altered by human activity, they provide many of the same ecosystem services as unaltered soils.  As such, soils can function in urban landscapes by reducing the bioavailability of pollutants; storing carbon and mineral nutrients; serving as habitat for soil and plant biota; and moderating the hydrologic cycle through absorption, storage, and supply of water.  In providing these services, soil plays a unique role as the “brown infrastructure” of urban ecological systems, much in the same way urban vegetation is thought of as green infrastructure. 

Urbanization affects soils and their capacity to provide ecosystem services directly through physical disturbance and management (e.g., irrigation) and indirectly through changes in the environment (e.g., urban heat island effect and pollution). Whatever the case, soils in urban landscapes are generally thought of as highly disturbed and heterogeneous with little systematic pattern in their characteristics.  As such, most studies have focused on human-constructed soils along streets and in highly impacted areas.  As a result, “urban soils” have been viewed as drastically disturbed, low in fertility, and not providing many ecosystem services.  However, observations of entire landscapes have shown that the chemical, physical, and biological response of soils to urbanization is complex and variable, such that soils that are largely undisturbed, of high fertility and function, also have been identified in urban areas.