Four species of Spartina (Spartina anglica, S. alterniflora, S. patens and S. cynosuroides) have been introduced to China, but currently only the first three are present and only the first two successfully reproduce on the Chinese coast. Spartina anglica and S. alterniflora were introduced to China from England in 1963 and from the United States in 1979, respectively. Today, S. alterniflora has expanded its coverage to more than 112 000 ha and S. anglica has declined to <50 ha. This is compared with only 260 ha of S. alterniflora and over 36 000 ha of S. anglica in 1985. The fates of Chinese Spartina, with dramatic expansion of S. alterniflora and significant decline of S. anglica, were different from those in other locations throughout the world. Factors affecting the growth of the two naturalized Spartina species in China include differences in artificial plantation strategy, impacts of tideland reclamation, species competition ability and genetic diversity. Several methods for Spartina control in China, such as harvesting, herbicide application and freshwater irrigation, have been developed, but more research is needed to verify their effectiveness.

Natural wetlands, occupying 3.8% of China's land and providing 54.9% of ecosystem services, are unevenly distributed among eight wetland regions. Natural wetlands in China suffered great loss and degradation (e.g., 23.0% freshwater swamps, 51.2% costal wetlands) because of the wetland reclamation during China's long history of civilization, and the population pressure and the misguided policies over the last 50 years. Recently, with an improved understanding that healthy wetland ecosystems play a vital role in her sustainable economic development, China started major efforts in wetland conservation, as signified by the policy to return reclaimed croplands to wetlands, the funding of billions of dollars to restore degraded wetlands, and the national plan to place 90% of natural wetlands under protection by 2030. This paper describes the current status of the natural wetlands in China, reviews past problems, and discusses current efforts and future challenges in protecting China's natural wetlands.

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Abstract-Optimal capacity analysis in multi-radio multichannel wireless networks by nature incurs the formulation of a mixed integer programming, which is NP-hard in general. The current state of the art mainly resorts to heuristic algorithms to obtain an approximate solution. In this paper, we propose a novel concept of multi-dimensional conflict graph (MDCG). Based on MDCG, the capacity optimization issue can be accurately modeled as a linear programming (LP) multi-commodity flow (MCF) problem, augmented with maximal independent set (MIS) constraints. The MDCG-based solution will provide not only the maximum throughput or utility, but also the optimal configurations on routing, channel assignment, and scheduling. Moreover, the MDCG-based optimal capacity planning can exploit dynamic channel swapping, which is difficult to achieve for those existing heuristic algorithms. A particular challenge associated with the MDCG-based capacity analysis is to search exponentially many possible MISs. We theoretically show that in fact only a small set of critical MISs, termed as critical MIS set, will be scheduled in the optimal resource allocation. We then develop a polynomial computing method, based on a novel scheduling index ordering (SIO) concept, to search the critical MIS set. Extensive numerical results are presented to demonstrate the efficiency of the MDCGbased resource allocation compared to well-known heuristic algorithm presented in [1], and the efficiency of SIO-based MIS computing compared to the widely adopted random algorithm for searching MISs.

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