BackgroundSince Spartina alterniflora (simplified as Spartina) has strong ecological competitiveness and rapid growth, it has been introduced and living in the coastal wetland regions of China for more than 30 years. Taking coastal wetland in the Beibu Gulf of south China as an example, the effects of Spartina invasion on soil quality were investigated to provide scientific basis for soil management.MethodologyThe soil quality of six different coastal wetlands, i.e. mangrove (vegetation coverage is above 95%), mangrove- Spartina ecotones (vegetation coverage is above 95%), sparse mangrove (vegetation coverage is 10%-20%), sparse mangrove- Spartina ecotones (vegetation coverage is about 80%), Spartina (vegetation coverage is about 80%) and bare beach (no plants), were analyzed using the following indicators: pH, cation exchange capacity, contents of total nitrogen, total phosphorus and organic carbon, microbial biomass carbon, microbial biomass nitrogen, microbial carbon / organic carbon, and activities of urease, acid phosphatase, invertase, polyphenol oxidase and catalase.Principal FindingsThe results showed that compared to mangrove wetland, most indicators in the mangrove-Spartina wetland showed a decline tendency except pH value, and the contents of total phosphorus and organic carbon, microbial biomass carbon and soil microbial biomass nitrogen, and the activities of acid phosphatase and invertase were significantly reduced (P<0.05). Compared to sparse mangrove wetland and bare beach, the Spartina invasion wetland (sparse mangrove-Spartina wetland and Spartina wetland) had higher contents of total nitrogen, total phosphorus and organic carbon, microbial biomass carbon, microbial biomass nitrogen, cation exchange capacity and the activities of urease and acid phosphatase, so soil quality in the sparse mangrove wetland and bare beach was significantly improved. Factor Analysis and PCA also showed that: the quality of mangrove wetland soil is better than that of mangrove-Spartina ecotones wetland soil; the quality of sparse mangrove-Spartina ecotones wetland soil is better than that of sparse mangrove wetland soil; the quality of Spartina wetland soil is better than that of bare beach wetland soil.Conclusions/SignificanceTherefore, in the invaded Beibu Gulf wetland ecosystems of south China, for the mangrove wetlands where the productivity of native plant was higher than that of Spartina, the Spartina invasion can cause soil degradation significantly and it must be strictly controlled, while for sparse mangrove wetland and bare beach where the productivity of native plant was lower than that of Spartina, Spartina invasion can improve the soil quality. Thus our study may help to better understand the effect of plant invasion.

Not only great tourism development value, but also huge risk for developing of uninhabited island. Scientific and reasonable planning and especially the choice of major tourism projects is one of the key factors of its success or not. Based on Qinzhou, the fuzzy selection model and clearing evaluation index system was used based on AHP, which determining the weights of different projects. Eight uninhabited islands were taken as the example to calculate the suitability of different project development in each island. The evaluation results is consistent with the guidance for the development and utilization of islands with no residents list by the State Oceanic Administration released in 2011, which show the research methods of China's uninhabited of the island development planning and management has certain theoretical significance and application value.

Abstract. It is one of the important methods to promote the sustainable development of tourism to fully tap the marine culture, enrich the modern leisure tourism. Danjia live in Qinzhou for many years and form a unique cultural. From the clothing, ship, shed of Danjia, this article analyzes its cultural factors firstly. Then it analyses the historical and cultural value; appreciation of the aesthetic value such as food, clothing, living room, festival ritual customs etc; experience value such as making and tasting seafood delicacy, making Danjia jewellery, visiting the temple, taking part in dragon-boat race on the sea and their wedding. Finally, it points out some suggestions for developing marine tourism of Danjia culture, such as respecting for nature and promoting sustainable development; planning rationally and building a good ecological tourism area; optimizing management mechanism, strengthening supervision and so on.

Taken the Seventy-two Paths in Qinzhou as example, the ecological carrying capacity of the tourism planning of uninhabited islands group was studied in the Northern Gulf of Southern China. Based on ecological footprint model, uninhabited islands consumption model of tourism ecological footprint was the established, from the view of the restaurant, accommodation, traffic, entertainment, sightseeing and shopping. And then, the ecological deficit was calculated through the evaluation of the tourism carrying capacity of uninhabited islands. The results showed that, (1) according to the planning, 5319.03 ha of total ecological footprint was required to meet the needs of the expected tourists; (2) to provide ecological footprint planning area are 788.56ha, the ecological deficit is 4530.47ha, and the ecological deficit is 5.75 times to provided by the local ecological footprint. It cannot bear the demands of ecological footprint, and a large number of external inputs were needed to maintain the ecological equilibrium Seventy-two Paths. Consumption model of tourism ecological footprint of uninhabited island could provide some reference to the development of uninhabited island in Southern China. At the same time, the model could enrich the theory and application of ecological carrying capacity.