出席國際學術會議心得報告
II. Establishment of Model Structure
This research will establish the objective of coastal environment in accordance with the characteristics of coastal resources. It will be integrated into the development model of coastal land use. The corresponding development amount of land use in the coastal environment will be measured under the mutual conflict of various objectives.
The basic concept of four objective functions and five constrains will be described in detail as follows.
1. Objective function
As for the development of private sector, most motive and objective for the coastal development is to pursue the greatest economic benefit. The impact on the ecological environment in the surrounding area is seldom concerned. But as the degree of demanding higher environmental standard by the people rises day by day, the public department should respond to the developing behavior of private sector in the policy with consideration.
As for the development of coastal area, the main region should be the one with natural resources or development potential. In order to achieve the protection and sustainability of resources, the principle which states that the conservation is more important than development for the use of coastal resources should be applied. In order to reduce the negative influence on coastal resources resulted by coastal development, the environmental supply aspect will be used as the constraint condition.
This research is conducted in accordance with the recommendations specified in
“The Planning on National Technological Project of Ecological Engineering” by relevant experts and scholars in environmental planning, coast engineering, ecosystem, and wetland conservation etc. (National Science Council, 2004), as well as past study results on the environmental function index of coast and wetland (Yen et al., 2005;
Yen et al., 2007). The coast has the functions of hydrology and chemical circulation such as purification of water, prevention of flood, protection of coastline, makeup of groundwater to water-containing stratum etc. The coast is called the “biological supermarket” (Mitsch and Gosselink, 1993), which is where the vast food chain and abundant biological diversity exist, so it also has the function of ecology. In recent years, due to a large amount of coastal land being exploited and the implementation of two days off per week, the coast is not only an activity center for general people, but also the best place of leisure for outside visitors, so its function value of recreation is increasingly important (the functions of coast are summarized in Table 1). From the description mentioned above, single economic objective should not be used as the trend for the development of coastal area; the ecological conservation and hydrological purification should be fulfilled, and the security of peripheral people in the coast and the satisfaction of visitor should be improved. Thus, this research summarizes four major objective functions for the establishment of coastal ecological environment and the integrated model of land use consist of those four functions:
ecological conservation ability, water pollution degree, preference for landscape perception, and economic function value. Their contents are described as follows:
(1) Maximum ecological conservation function
As for the habitat of species, when a bigger patch is divided into smaller patches, the inside habitat will be changed, causing the size and the number of different inner groups to be reduced. The patch size is the main parameter for studying the characteristics of landscape, because it directly affects the amount of living beings per unit area, the productivity and storing amount of nutrient, and the species composition and species diversity (Forman and Godron, 1986; Marsh, 1991; Forman, 1995;
Bourgeron et al., 2001). As for a specific species, a larger patch will have a larger community compared to a smaller patch, so the regional extinction is not easy to occur in the larger patch. On the contrary, if the patch is too small, the probability for regional extinction of species will be increased. This happens mainly because that the larger patch consists of more habitats, allowing more different species to coexist compared to a smaller patch, and the regional extinction is not easy to occur (Forman and Godron, 1986; Forman, 1995; Dramstad et al., 1996). From the above-mentioned description, it is known that if the patch size is larger, the conservation ability will also be higher. On the contrary, if the patch size is smaller, the conservation ability will be lower. So, this research takes the study, The Ecological Index of Landscape, conducted by Forman (1995) as a reference, and selects the mean patch size (MPS) related to land-use area as the index for evaluating the ecological conservation function of coastal area.
The MPS is employed as the evaluation standard of ecological conservation ability in the objective function of maximum ecological conservation function. If the MPS is larger, then the scope of ecological influence will be more concentrated, and the conservation ability will be better. So it is defined as the characteristics of looking for maximum.
(2) Minimum water pollution degree
The pollution degree of coastal water is an importance index of assessing the environmental quality in the coastal area. There are many methods to measure water pollution degree. For example, the dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total phosphorus, ammonia nitrogen, suspended solid and coliform etc. (Canter, 1977). The amount of oxygen dissolved in water is called the dissolved oxygen. The fish and shellfish can only breathe in the oxygen dissolved in water. The microorganism will also use part of oxygen dissolved in water to decompose the organic substance into simple substances.
The amount of oxygen consumed by the microorganism for decomposing the organic substance is called the biochemical oxygen demand (BOD). If there are more water pollutants, the BOD will be higher. A good water area must have high DO and low BOD.
When the function is established, it is necessary to consider if the information is easy to be extracted, and whether the water quality model is reliable or not. After various water quality parameters are assessed, this research select more reliable and common BOD-DO model as the water quality model (Canter, 1977). But considering that the velocity of water flow is fast for the rivers on the western coast in Taiwan, the DO can be kept above the standard of water, so this research uses the BOD as water pollution index, and it is defined as the characteristics of looking for minimum.
(3) Maximum landscape perception preference
Often, the issue of social and psychological aspect is not considered for the coastal development. This research will use the investigation method of “scenario
feeling degree” to study the landscape perception preference of outside visitor on the coastal environment. In the estimation methods of landscape preference, the most familiar and popular one is the Scenic Beauty Estimation (SBE). The SBE was proposed by Daniel and Boster in 1976. It is considered that the landscape perception of mankind depends on the beauty experience of landscape and the beauty judgment standard (Schroeder, 1984). Among them, the beauty experience is influenced by the landscape beauty, and the judgment standard is different due to the influence of past personal experience and environmental background. In order to eliminate the error due to the use of different judgment standards, the SBE is proposed.
This research adopts the environmental perception scales established by Schroeder in 1984 as the standard of SBE. According to the category scales, the equal distance scales of psychological attribute is established from the judgment of subjects directly. The subjects are asked to classify or grade the landscape pictures according to the category or rank of how the questionnaire is designed. Finally, the constructed scales is used to calculate the landscape perception preference function of land-use item, and larger preference value represents higher landscape value, so it is defined as the characteristics of looking for maximum.
(4) Maximum economic function value
The coastal land development will create external effects because of the environmental resources, making it difficult to directly estimate its economic efficacy from the cost. The value (V) is the ratio of the external function (F) to the internal cost (C) (V = F/C), and the external function value is the objective cost value (Li, 1995).
So, if the external function of land development can be quantified by the estimation of objective cost, the unit value of every land development can be estimated by dividing it into the unit cost. This value can be regarded as the economic efficacy of land development, which is the unit development efficacy obtained from the investment per unit cost. Because it is a unit ratio, when it is multiplied by the land use area, the economic efficacy of land development can be obtained, and the sum of objective equations will be the total “economic function value” of land development. This research will use the sum of function value of every land use category as the objective function for the assessment of economic efficacy of land development, and it is defined as the characteristics of looking for maximum.
2. Constrains
Through the objective function, the development efficacy of coastal land searched by the planner can be achieved while maintaining the balance between each objective. But in reality, the development scale of coastal land often depends on the upper limit of regulation allowance and other constrains. Therefore, this research considers the influence of objective environment based on the setup of planning objectives. After both the land use zone and permit category are determined, according to the use area of coastal land, land use category and specification, ecological conservation, and recreation plan, the most suitable development scale can be sought in order to obtain the balance of every objective.
This research regards the coastal area as the main research subject. As for the constrains of development area and the objective conditions of developer, total area of coastal region, the upper limit of total allowable development area, the upper limit of every land use area, and the lower limit of every land use area are being considered respectively. They are described as follows:
(1) Total area of coastal region
In the research field, the sum of every land area should be equal to total area of coastal region. So, total area of coastal region is considered as a restraint condition.
(2) The upper limit of total allowable development area
In order to prevent over-development, total allowable development area should be restrained (such as residential land, industrial land, recreational land, agricultural land, transport land etc.). The upper limit of total allowable development area is obtained by subtracting the restrained development area (the environmental sensitive area) from total area of coastal area.
(3) The upper limit, lower limit of every land use area
Total area of every land use zone in coastal area should has the constrain of upper limit and lower limit according to its current development situation, regional characteristics and future policy requirement and direction. This restraint condition not only can comply with the actual development requirement, but also can avoid the infinite large or small objective function.