A Conceptual Ecological Model of Cangzhou Coastal Wetlands, Hebei Province, China

Abstract

Conceptual ecological models (CEM) are non-quantitative tools that identify the major drivers and stressors on ecosystems, the ecological effects of these stressors, and the best biological attributes or indicators of these ecological responses. Located in southeast Hebei Province, just west of the Bohai Bay, the Cangzhou coastal wetlands (CCW) are complex coastal wetlands formed and influenced under the dual driving forces from both rivers and oceans. They cover an area of 136 000ha, which are mostly dominated by reservoirs, salt fields, shrimp ponds, tidal creeks, coastal brackish and marshes, shallow sea, as well as broad mudflat beaches. In recent years, population growth and economic development, rapid industrialization and urbanization, have result in severely wetland degradation and environment deterioration. A CEM has been developed for the CCW to understand the coastal wetland system and its response to natural and anthropogenic stressors. Drivers on the system are port construction, urbanization, industrial and agricultural practices, and water management. These drivers lead to five major ecosystem stressors: built-up area expansion, irrigation and drainage system, hunting and over-fishing, nitrogen and phosphorus input, and toxic pollutants input. Attributes that are affected by these stressors and can be used as indicators include fishes and aquatic fauna, wading birds, ecological and environmental events. As critical linkages between stressors and attributes, the ecological effects of the stressors are: reduced spatial extent, compartmentalization, altered hydrology, degraded water quality, and altered salinity regime.