在所有會造成生物棲地破壞人類的活動中，都市發展是導致物種區域性滅絕率最高及棲地回覆最困難的一項（Vale, 1976）；除此之外，它亦會使當地原生物種受到快速蔓延的外來種取代，進而失去生態上的獨特性。截至目前為止，都市化仍是全球的趨勢，因此在都市發展時同時間兼顧當地的環境及生物多樣性是重要且迫切的課題。其中一項被廣泛應用於都市規劃的指標是在1980年代德國柏林提出的「生境面積指數」(Biotope Area Factor, BAF)。BAF由該地區的地表透水性、植物覆蓋狀況以及人為建物等表面形態決定，表示這個區域中「有效生態面積」的比例，用以代表當地的「生態有效」程度，任何的開發與建設都需要維持一定的BAF值。然而BAF值是依據照片或空照圖，交由專家以問卷調查的方式決定，其是否能忠誠的反映現地實際生物多樣性尚不清楚。都會區中的公園由於擁有較高的植被覆蓋率，往往會成為生物多樣性的熱點，因此在都市計劃中對公園進行適當的規劃對於提升城市生物多樣性會是很重要的一點。在本研究中，我選擇中台灣地區多個不同型態個公園欲檢視BAF值是否能確切反映現地的生物多樣性、並找出對生物多樣性有較高影響的環境因子。我調查各公園中蜘蛛、昆蟲、木草本植物的多樣性、紀錄環境因子，並以專家問卷法計算各種同質單元的BAF值。結果發現，BAF值不論與生物多樣性指數或物種組成差異皆無顯著相關。葉面積指數、草本植物覆蓋度能顯著反映草本植物與蜘蛛之多樣性，林下植被密度則能顯著反映昆蟲多樣性。本研究之結果顯是現有之BAF系統並無法忠實反映地景嵌塊之生物多樣性，因此發展出新一代之生態有效性權重方法有其必要性，本研究所累積之大量資料將有助於在台中市建立一套能準確評估地景嵌塊生態有效度之新一代權重系統。 In all the human activities which cause natural habitat loss, urbanization produces the greatest local extinction and its detrimental effect lasts longer. Besides, urbanization processes would replace the native species with widely-distributed nonnative ones and result in the loss of biotic uniqueness of local ecosystems. In recent years, urbanization is still a growing global trend so the application of biodiversity-enhancing managements during urban development is urgent and important. One popularly-used management conduct is the BAF (Biotope Area Factor) system, which was developed in Berlin in 1980s. BAF represents the ratio of ecological effective area of a landscape mosaic and in many cities the developers must achieve a required level of BAF values in their design to obtain construction approval. However, currently BAF values are generated by expert questionnaire methods using aerial photos. It is not clear whether BAF values can actually reflect the biodiversity of a local area. Because of their high vegetation coverage urban parks are often regarded as the biodiversity hot spots in cities. Therefore, how to manage city parks to increase diversity and abundance of organisms is vital in enhancing the biodiversity of urban areas. In this study, we established sampling plots in various types of parks in metropolitan areas in central Taiwan to evaluate the congruency between BAF values and in situ biodiversity and to realize what environmental attributes are responsible for high biodiversity in urban parks. We used expert questionnaire methods to designate BAF value of various landscape homogenous units in these parks. In addition, in all sampling plots we systematically surveyed the diversity of spiders, insects, herb plants and measure vegetation structures. The results showed that in all taxa examined no significant correlation was found between BAF values and diversity indices. Understory vegetation density was the only factor significantly correlated with insect diversity. The diversity of herb plants and spiders were significantly correlated with leaf area index and herbaceous plant coverage. These results indicate that a new generation ecological effectiveness weighting system which can realistically reflect local biodiversity and ecological condition is needed and data collected in this study can be used to generate such system in Taichung City.
