應用聯合分析法評估桃園許厝港濕地之生物多樣性價值

A Conjoint Analysis Applied to Value the Biodiversity of Xu Chu Kang Wetland in Taiwan Taoyuan

黃政仁(Jheng-Ren Huang)

指導教授 ： 錢玉蘭

國立臺北大學/公共事務學院/自然資源與環境管理研究所/碩士(2014年)

摘要

生物多樣性的存在關乎生態系統的維持與永續，也關乎人類的生存，但在工業革命以後，人類快速經濟活動與大量消耗能資源的生活方式卻促使全球生物多樣性快速下降，因此科學家紛紛提出生物多樣性的重要性，並多方嘗試衡量生物多樣性對人類帶來的經濟價值，以提醒人類應致力於保育生物多樣性。
完整的生物多樣性概念需包含基因、物種及生態系統等三種層次，但過往文獻為了評估上的方便，多以物種數多寡做為測量生物多樣性的依據而忽略物種均勻度與生態系統的概念，但此概念並非完整的生物多樣性概念，也可能忽略民眾生物多樣性之理解程度及不同物種知名度對評估生物多樣性價值的影響。
為改進生物多樣性的評價方式，本研究選定鄰近桃園縣大園工業區的國家級濕地－許厝港做為研究地點，因為該濕地是西北沿海的重要野鳥棲地之一，卻也同時面臨桃園航空城開發壓力與工業區汙水排放及廢棄物堆積等問題，導致生態面臨相當大威脅。在評價生物多樣性時則採用文獻中常用之聯合分析法（conjoint analysis method, CAM）與選擇試驗法（choice experiments, CE），但在問卷設計上改善過往研究過度簡化生物多樣性概念的缺點，在各保育方案之生物多樣性屬性設計上，改善以下幾個方向：（1）將民眾在濕地常見鳥類依據其保育重要性程度，在設計鳥類屬性之各水準時，將不同保育方案內之鳥類保育水準加以區分為一般鳥類與保育鳥類，（2）加入鳥類物種均勻度，做為生物多樣性的一個屬性，（3）加入生態系統多樣性的概念，配合許厝港海岸濕地之常見濕地型態，將生態系統屬性區分為潮間帶或灘地、草澤及林澤（紅樹林）等三種水準。另外，透過聯合分析法之評分、排序，以及選擇試驗法之最佳選擇等三種評價方式，嘗試瞭解民眾不同評價方式對於生物多樣性價值評估可能產生的影響。
經過等機率三階段分層隨機抽樣，回收302名全國居民與250名桃園縣當地居民的問卷資料進行實證分析，研究結果發現：（1）全國約有一半的人聽過生物多樣性；（2）影響民眾對生物多樣性之效用的屬性偏好依序為底棲與潮間帶生物、鳥類豐富度、鳥類均勻度、濕地型態，顯示民眾或者原先即有完整的生物多樣性，或者在經過本問卷提供之說明卡解說後即能有完整的生物多樣性概念，因此回答各項選擇方案時能夠有此結果；（3）「一般鳥類」的邊際願付價格曲線大致貼近邊際效益遞減的趨勢，但「保育及特有鳥類」則不一定；（4）研究實證結果發現在樣本數有限情況下，排序的評價方式最能兼顧資料細膩度與資訊超載（information load）問題；（5）較理解生物多樣性概念的人會更看重鳥類豐富度、底棲與潮間帶生物屬性的保育能否有明顯提昇。

關鍵字

許厝港濕地 ； 聯合分析法 ； 生物多樣性

並列摘要

The biodiversity is related to not only the sustainability of ecosystems, but also the survival of mankinds. Since the industrial revolution, accompanying by human’s economic activities and wasteful lifestyles, the global biodiversity is declining rapidly. In order to convey and persuade people to conserve biodiversity, scientists constantly try very hard to find ways to evaluate the biodiversity.
A comprehensive definition of the biodiversity is indicated by the different genes and species of the living beings, and the ecosystem for them to live in. Compared with species evenness and ecosystems, the species richness (the number of species) is relatively easy to be measured, the prvious studies in literature maily focused on the species richness instead.
In this study, we choose the Xu Chu Kang wetland in Taiwan Taoyuan as a study site. Not only is it classified as a national wetland and an important bird habitats in the northwest coast of Taiwan, but also it is faced tremendous incrasing threats both from the pollution of the adjacent industrial area and the government’s recent development plan of the Taoyuan-Air-City.
This paper aims to evaluate the biodiversity by applying the conjoint analysis method and choice experiments. In order to improve the shortcomings on oversimplifying the concept of biodiversity in previous studies, we carried out several improvements in the survey design as follows: (1) dividing wetland birds into general birds and protected birds based on their conservation importance; (2) introducing birds’ species evenness as an attribute of biodiversity; (3) incorporating the concept of ecosystem diversity as an attribute of biodiversity. The type of wetland ecosystem is then classified as the intertidal zone, the marsh, and the swamp (mangroves) based on Xu Chu Kang’s status quo. In addition, this study also assesses how the elicition methods in conjoint analysis method (scoring, ranking) and choice experiments (best choice), that the correspndents use to express thir preference for diffent conservation choices, affect the valuation of biodiversity.
After a stratified random sampling with the equal probabilities principle and a three-stage sampling design, we had gotten valid surveys for 302 national residents and 250 local residents. After analyzing the data, we conclude the following: (1) About half the people across the country heard biodiversity. (2) People prefer higher biodiversity. In terns of different biodiversity attributes, people prefer benthic organisms attribute first, bird species richness attribute next, bird species evenness third, and wetland type attribute last. The results suggested that people have a complete concept of biodiversity, perhaps because people’s prior knowledge or interviewer's instruction card quide them to elicit their preference for biodiversity attributes. (3) The marging willingness to pay (MWTP) curves of the general birds are consistent with the law of diminishing marginal benefit. In contrast, the MWTP curves of the protected birds are not all consistent with the law of diminishing marginal benefit. (4) With limited numbers of samples, ranking method does take into account the fineness of data and the problem of information load. (5) People who have more knowledge about biodiversity will pay more attention to the bird species richness and the benthic attribute.

並列關鍵字

Xu Chu Kang Wetland ； Conjoint Analysis ； Biodiversity

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