This article is a study on the management of wetland. The future impact of landscape of coastal wetland with the constant changes of human activities is discussed on the basis of the theory and methodology of landscape ecology. Solutions to the contradictions of ecological protection and port construction are put forward.
Base on the theory of system’s point of view, the port construction in coastal areas will doubtlessly contribute to certain impact on the ecology of that area. Therefore, the study of this matter aims to find out ways as for how to improve and maintain the stability of coastal ecosystem in the construction of port. And it is of great signifi- cance to study the relations between the ecological protection and the economic activity in a wetland like the Meizhou Gulf that has a poor ecological environment. Besides, “Port city of Meizhou Bay Development Plan” prepared in 2010 defined that the Meizhou Bay will be the region focus on the development in Fujian Province [
Meizhou Gulf District, including Putian, Xianyou and Hui’an counties with a large population and insufficient land, is located at 118˚27'E - 119˚22'E and 25˚N - 25˚46'N. The total area is 4703.57 square kilometers; the coast line is 186.57 km and the land area 2166.13 square kilometers. Along the coast, beach covers 207.04 square ki- lometer, which is the third largest in the province. The 5-meter-deep sea area is 95.99 square kilometers, the fifth largest in the province. According to the definition of wetland given in Ramsar Convention, water area with the depth of less than 6 meters belongs to wetland. But then in 1974, the USFWS (United States Fish & Wildlife Supervision) said that deep water area of over 2 meters could not be considered as wetland. They held the opi- nion that the landscape ecology system of wetland and the landscape system of deep water are continuously dis- tributed. According to the situation in Meizhou Gulf, the definition given in Ramsar Convention and classified by Lu Jianjian (1998) is more applicable [
Meizhou Gulf is a half-closed bay facing the southeast. Stretching from the north to the west and then to the south are Putian, Xianyou and Hui’an counties. The landforms belong to volcanic rocks and tableland of red soil; the south and north banks belong to a coast of slightly-eroded bedrock and the west bank is a coast of mud. The coastline extends a little bit into inland and then meets the wide wetland area. In the whole ecological environ- ment, due to the long time impact of human activities, the existing vegetation has been destroyed and became secondary biocenosis where there is a shortage of surface water. As a result, the vegetation available includes scrub-shrub, grassland and brushwood, etc. The soil in most of the shoals is saline soil and some is red soil in tableland. Owing to the blind exploration in the past, the quality of the ecological environment of coastal wet- land has been degraded greatly, resulting in waste of large area of land, destroy of vegetation, serious soil ero- sion and poor use of land [
A sketch map of Meizhou Gulf
Huangtang Stream and Longjiang River. So water resources are short and spatial distribution of biocenosis is in a free style.
The structure of wetland landscape ecology system shows the inner constitutions of the system and the results of interrelation and interaction. According to usual practice, the system consists of non-biological elements and bi- ological elements [
The edge effect of wetland landscape leads to a rich biological diversity [
Port construction will involve tideland enclosure, filling for land construction and bank construction, which will have direct impact on wetland ecology system [
Using the view of ecological landscape, port construction will change the land use pattern. The connectivity and homogeneity became higher and then lower the ecological quality of ecosystem, because of the rapid ex- pansion of construction land [
So, accompanying with the port construction, the effect of the narrow scope of the gulf ecosystem could be described as the following: 1) human disturbance changes the equilibrium and stability of biological circulation and earthly chemistry circulation, especially on the initial input, it changes the direction and velocity of circula- tion process; 2) heterogeneity, an important role player in ecosystem, could provide group growth relationship among different elements, proceed the rational use of natural resources and prevent the further catastrophe; 3) wetland landscape changes would influence the stability of the neighbor land and marine ecosystem.
If urban expands rapidly, the agricultural and green land pitch will keep enough amount to maintain the land- scape quality. Now the irrational spatial distribution of industry land had caused more environmental pollution. At present, the Meizhou Gulf Port is under construction and there are only a few industrial facilities along the coast. But survey shows that the intertidal and seabed water quality are polluted by oil. The average oil content of water quality exceeds 79 microgram/liter. The oil content of seabed water quality in the middle tidal area in Xiuyu and Xiaocuo is 215 mg/kg and 300 mg/kg, respectively. According to analysis, it is caused by the sewage discharge of ships and the pollution produced by the demolishing plants in Xiuyu and Putian. Putian Ship De- molishing Plant has several 10,000-ton ships broken down over the past few years, resulting in serious pollution and damaging the aquaculture in the locality. So, to protect the wetland ecological environment, this plant should improve its techniques. From a long-term point of view, ship demolishing plants should move to the outer bay. The water examination reveals that oil is the main pollution, then comes phosphorus and nitrogen. The inner bay and Xiuyu are more seriously polluted than the other parts. PH, DO, BOD, DDT, Prussiate, Phenolle, As, heavy metals and BHC can meet the first class seawater standard while Hg, Pb and Zn go beyond the standard.
The marine ecological system is a big system consisting of food chains related to each other. The wetland landscape and deep-water landscape in Meizhou Gulf are continuously distributed. In coastal waters, pollutant produced by port industry and civil facility is the main pollution. After the construction of the port is finished, the growing economic activities such as sewage discharge and oil-spill will pollute some areas resulting in the deterioration of water quality. When the port is put into use, the standard for water quality will be degraded from Class 1 to Class 3. Normally, the remanent current will flow to the entrance of the gulf and will help move floating pollutant outward. However the surface remanent current in the inner Meizhou Gulf is flowing to the southeast, therefore the pollutant will gather in Dongwu and pollutes the area. Although in the north of Liyuwei, current velocity is big and is favorable for the diffusion of pollutant, the remanent current here moves into the bay, and will prevent the diffusion of pollutant. Therefore, it is better to build the oil dock in the south of Liyuwei.
In some words, pollution around gulf may lead to the following results: simple system structure, lower species diversity, fewer organism production and the shift of system circulation.
The terrain in the west of the Gulf slopes gently. The wetland includes the area where the depth is less than 6 meters. The ecological environment of this area is interacted by sea and land. On one hand, as there are no rivers running in, the impact of land on the wetland in water area is small. On the other hand, as the bay is 33 km in depth, the wetland in water is far away from the mouth of the bay. As there is little exchange of current with outer sea over long period, the contact of sea water and air is affected, and the absorption of oxygen is difficult. When water is polluted, it turns stink and discoloration, thus degrades the quality of water. In most of the time in a year, the wind goes eastwards, when tide ebbs and is disadvantageous to the diffusion of pollutants. Those above facts lead to the decrease of biological diversity in the coastal wetland of Meizhou Gulf. According to a survey (
Port construction will change not only the land ecological system, but also reduce the marine ecological sys- tem and the diversity of living things in coastal waters. Port construction will also change the route of fish and
. Seawater chemical content in Meizhou Gulf
Item | Layer | Spring | Summer | Autumn | Winter |
---|---|---|---|---|---|
Oxygencontent (ml O2/L) | Surfacelayer | 6.10 | 4.33 | 5.19 | 6.36 |
bottom | 5.79 | 4.22 | 5.12 | 6.36 | |
Oxygen saturated degree (O2%) | Surfacelayer | 121 | 96 | 103 | 103 |
bottom | 113 | 92.4 | 101 | 103 | |
Phosphatic (μmol P/L) | Surfacelayer | 0.04 | 0.25 | 0.28 | 0.47 |
bottom | 0.04 | 0.29 | 0.43 | 0.45 | |
Silicate (μmol Si/L) | Surfacelayer | 0 | 6.50 | 17.20 | 18.10 |
bottom | 0 | 5.40 | 16.80 | 19.10 | |
Three kind of inorganic nitrogen (μmol N/L) | Surfacelayer | 0.39 | 1.80 | 11.58 | 12.76 |
bottom | 0.29 | 1.59 | 12.14 | 12.70 | |
pH value | Surfacelayer | 8.45 | 8.16 | 8.25 | 8.20 |
bottom | 8.44 | 8.17 | 8.28 | 8.21 | |
Alkalinity (meq/L) | Surfacelayer | 2.27 | 2.26 | 2.08 | 2.19 |
bottom | 2.32 | 2.31 | 2.15 | 2.32 | |
Salinity (meq/L) | Surfacelayer | 31.45 | 33.96 | 30.69 | 30.42 |
bottom | 31.98 | 34.01 | 30.91 | 30.47 | |
Water temperature (˚C) | Surfacelayer | 20.78 | 26.69 | 21.45 | 11.22 |
bottom | 19.70 | 26.03 | 20.66 | 11.08 | |
Planktonic flora (×104 individual/cubicmeter) | 1014.94 | 26.10 | 2.83 |
Source:
shrimps in coastal waters. Animals and birds will migrate, and aquaculture resource will be destroyed, which will reduce the diversity of living beings to different extents. The construction of dock and embankment may change the velocity of tide and soil and sand will silt. According to fieldwork, a dam has formed in the main channel in the northwest of Meizhou Gulf. At the depth of 4 meters, it is widened by about 1 meter and height is raised by 14 cm every year. There is tide partition here, and a convergency area of bottom current as well. It is also the main cause to silting. If the proposed enclosure works in Liyuwei can be carried out, the dam will probably be moved southwestwards and there will be more silt in the main channel. If the enclosure works is carried out properly, and the dam is moved to inner bay, the channel will not be blocked. Therefore, the enclo- sure works in Liyuwei has to be done carefully. As for the regular pattern of tide between Xiaocuo and Xiuyu, the surface velocity of tide rising is smaller than that of ebbing, and bottom velocity is just the opposite, which is unfavorable for sand moving given the bottom flow affects silting. According to the survey, when the on-going construction of enclosure in Nanpu is completed, it will reduce 24,000,000 cubic meters of total amount receiv- ing tidewater and thus decrease the water depth of the section in Xiuyu and Xiaocuo by 4 meters. The dunes in the northwest of Putou will move toward Baishijiao accordingly.
The change of the landscape ecology system in Meizhou Gulf is inevitable, because the use of land in large area will change the pattern of the landscape. The existing landscape of Meizhou Gulf is dull, the succession of the ecological system is degenerating, the vegetation coverage of the earth’s surface is small and large areas of land are deserted. It is difficult to upgrade the habitats of landscape through natural succession. As the construction of the port disturbs the normal succession and destroys the balance of the succession of habitats, the wetland habi- tats of landscape ecological system is degenerating at a higher speed than that of natural upgrading. In the course accelerated the construction of the port, wetland habitats that have lost biomass can be developed. It is impossi- ble to recover all the original wetland ecological system because wetland area is becoming smaller and smaller with more land being used for construction. The building of tide barrier and dam also expedites the physics and chemical change of the environment. Therefore, upgrading of the habitats is one of the last resorts that can maintain the stability of wetland landscape habitats. The upgrade can be done by means of certain recovery techniques, such as select a new species instead of the original tree population, to maintain the stability of the natural habitats in different stages of succession so as to protect the diversity resource of living beings in differ- ent habitats. Meanwhile, it recovers the habitats that have been occupied and damaged by human race through natural upgrading organism. In this way, the contradictions of biology protection and wetland development can be eased up. At present, the wetland habitats of Meizhou Gulf are at the stage of regressive secondary succes- sion. Measures for recovery should be laid out at the time when planning the land for construction. Such land as enclosed beach and intertidal wetland that will not be used for construction should be included in kernel area. Even if they are not the main habitats for creatures under protection, they are source of succession and are po- tential places for creature protection. If they are destroyed, new organism will be destroyed and habitats will be degraded.
It is suggested here that Shelter-forest belt be built in a proper area, such as Xiaocuo port and Xiuyu port of the northern shore of Meizhou Bay coast, to meet the needs for protection and construction. By protection zone or conservation, it means a given area that may also have limited human activities. So it is different from a nat- ural conservation. In a natural conservation, traditional methods for protection are adopted and some natural ha- bitats are separated and closed and will not be affected by human race. However, a landscape ecology conserva- tion is built to protect certain amount of landscape that will not be used or used limitedly for production. This is possible if only port construction will not affect the function of conservation. As for Meizhou Gulf, the land- scape that requires protection includes the existing ecological system, for instance, shallow waters and man- made ecological system such as saltern in the upper wetland, green belt in the construction area, off-fishing area and shelter-belt, etc.
So as to set up conservation for landscape ecology in the following areas so as to maintain the stability of the landscape ecology system in Meizhou Gulf: 1) Setting up shelter-forest in the south of Xiaocuo and Xiuyu, in the north of Dongwu, the purpose of which is to prevent, or weaken the energy flow by strong wind to protect the port construction area and to change the micro-climate; 2) Setting up connective protection zones in the up- per wetland of Shanyiao Bay to prevent the substance, energy, biology and of each landscape element from be- ing blocked. There is a natural passage from saltern to its adjacent waters. The protection will be favorable for the natural growth of wetland habitats; 3) Building protection embankment in Dongwu and Xiaocuo where wind is strong to serve as a buffer. Besides, build green belts in the construction areas in Xiuyu, Xiaocuo and Dongwu to reduce torrid effect and air pollution (See
Meizhou Bay port city group includes the Xiaocuo port, Xiuyu port and Soochow port. The main building in port and the area between land and sea overlap, so the construction of ecological protection areas within the port
Planning map of landscape ecological conservation
land can effectively relieve the impact on port construction to local wetland ecosystem.
Meizhou Gulf is a newly-built port area. It is clear that land used for the construction will take up much of the wetland habitat. Preparations should be made for the long-term environment protection in addition to the estab- lishment of protection zones. Therefore, it is suggested here that 3S (GIS, GPS, RS) integrated techniques be used to develop coastal resource and environment information system in order to monitor the landscape ecology of wetland.
The coastal wetland factors are complicated and changeable. The biological constitution and the non-biolog- ical constitution of the ecological system are changing all the time. Gloabal Positioning System (GPS) makes it possible to locate the wetland accurately and is convenient for survey and data collection. The remote image of Remote Sensing (RS) techniques provides the most essential data for regional landscape analysis and is also the direct means to learn about land use and coverage change. GIS (Geography Information System), with its po- werful function of space analysis and data memory, can carry out quantitative analysis and statistics of wetland habitats [
The concept of CWREIS supported by Areview covers the following points: 1) system database includes ba- sic data, attribute database and space database. The data come from field survey, statistics data of social econo- my, environmental changes data, maps and remote image, etc. After data is in and being digitalized by Areview, the data will also be stored in its text pattern. 2) The system structure consists of data information source, pre-data processing, applied analysis mold, auxiliary strategy and output. The data managing mold makes it possible to carry out all kinds of operations, to input and output data, to inquire and to add up. The space analy- sis mold will help carry out space data operation, overlay, buffer analysis, adjoining analysis, classification and visualization. The pattern calculation mold can create new mold and simulation mold of wetland habitat charac- teristics, such as mold of environment evaluation of wetland, land use and mold of coverage change, so that it can do the analysis of attribute data and mathematical pattern. 3) The function of the system will provide space analysis. For example, discuss the affected area of wetland enclosure on the basis of buffer analysis and study the quality of wetland environment and the distribution of biological diversity. Besides, a comprehensive analy- sis can also be made on environment and social economy. Therefore, the proposed system function aims to serve the local government as an auxiliary means in resource development and construction programs to ensure coor- dination between human activity and environmental protection. 4) System actualization: CWREIS will use Vis- ual Basic and Areview of GIS, supported by systems over Window 3.1. As Areview supports different data pat- tern and other standard pictures, database and texts, it has a complete function of GIS. It can be used for space data management, inquiry, search and space analysis. As for the management of attribute database, use Fox- pro.
Meizhou Gulf has a complicated environment and ecological system structure. The study of the wetland aims to meet the needs for the construction and development of the port. It can be foreseen that human activity in this area will further affect the whole ecological system of the gulf. When the plan for the development of the port is made, the protection plan should also be considered for the ecological systems of wetland and deep-water habi- tats. The stability of the ecological system can be maintained by setting up the landscape ecological conservation. The setting up of a resource and information system, CWREIS, on the basis of information technology will make it possible to monitor the change of the coastal habitats.