Wetlands are one of the most important ecosystems on Earth. They usually contain thousands of species in their aquatic and terrestrial environments, provide important habitat to animals, and play a special function in hydrology.1 However, wetlands were once considered as having little economic value.2 As a result, the drainage and alternative usage of wetlands (e.g., transforming to croplands or pastureland) became common practice around the world and was even encouraged by specific governmental policies. Statistical results of Mitsch and Gosselink3 and Mitsch2 showed that wetlands, globally, were decreasing at a fairly rapid rate. Fifty percent of the world’s original wetlands had disappeared since the 1790s. Moreover, climate change, as another major threat to the survival of species and ecosystem integrity,4 will affect the hydrology of individual wetland ecosystems, mainly through changes in precipitation and temperature. Usually, such impacts will immediately post concerns for wetlands.5 With the decline of wetlands, other habitats are also lost.6 These include biogeochemically active areas, frequency flood buffers, and major natural sources of reduced gases (e.g., methane and sulfur compounds). Many governments have set up nature reserves to protect wetland areas;7–9 however, inherent conflicts exist even today between the need for more croplands and for environmental protection. For example, some wetland nature reserves in eastern China were not well protected and even lost due to agricultural activities.10 Thus, the effectiveness of establishing a wetland reserve for the protection of its vegetative coverage needs to be evaluated.