Effects of Urbanization on Soil Carbon and Nitrogen Cycles in The Riparian Zone of Low-order Watersheds

Xiupeng Zhang, Fordham University


Riparian zones, as the interface between upland and river channel, have important ecosystem functions. Unfortunately, riparian zones of low-order watersheds are affected by urbanization-related disturbances. This dissertation combined field and modeling studies to systematically and quantitatively assess the effects of urbanization on C and N cycles in the riparian zone of low-order watersheds. Field studies across three low-order watersheds, differing in the degree of urbanization, in the New York Metropolitan Area indicated soil total C and N, and SOC in soils and water differed with urbanization degrees, and soil and water NO3- and NH4 + varied more temporally than spatially. C and N in soils and water exhibited higher contributions from human-related sources in urban watersheds. Soil and stream water inorganic N, rather than organic C, differed in response to extreme precipitation events (two moderate droughts and one flash flooding event), and the responses differed with the degree of urbanization. The Riparian Ecosystem Management Model (REMM) was modified to simulate soil C and N cycles in urban riparian zones. Simulations indicated that, if current urbanization continues, soil C and N cycles will experience fundamental changes within a period of decades. In sum, these results indicate ecological functions, including biogeochemical and hydrological regulation and water quality control, are crucial to low-order urban watersheds, and can be affected by urbanization. Further, restoration and conservation of riparian zones in urban watersheds is critical for developing sustainable cities and healthy urban ecosystems.

Subject Area


Recommended Citation

Zhang, Xiupeng, "Effects of Urbanization on Soil Carbon and Nitrogen Cycles in The Riparian Zone of Low-order Watersheds" (2017). ETD Collection for Fordham University. AAI10621280.