綠屋頂環境屬性與生物多樣性關係之研究

Abstract

隨著人類活動與開發程度的提高，城市的灰色基礎設施、各類建築物與道路等已開發土地持續擴增。這些大型量體與鋪面，造成了棲地破碎化，使得都市中的物種在空間分佈、生存與繁殖上受到干擾。 近幾十年來發展興盛的綠屋頂技術，具有增加都市綠地面積、減少建築物表面逕流、隔熱降溫與節能等功能。除此之外，若以景觀生態學的角度來看，綠屋頂可為生活在都市的物種提供庇護、棲息與移動的場所，提高生物多樣性，進而促進健全的都市生態系。然而，設置於建築物之上的綠屋頂，其在生物多樣性上的效益仍受到基地樓高、周邊綠地與建物環境等實質環境屬性因子所影響，綠屋頂形式、植栽類型、綠化面積等綠化條件的不同也會對其造成程度上的差異。 因此，本研究之研究目的在於瞭解都市中不同的綠屋頂之物種組成情形，以及探討綠屋頂的不同環境屬性因子與生物物種的分布狀況之間的關係，以作為未來的都市規劃、綠屋頂推廣，在基於生態考量上，綠屋頂的設置與分佈建議依據。 本研究以新北市環境保護局低碳中心推動的建物綠化示範推廣計畫及參與式屋頂農場推動計畫之8座屋頂農場作為研究地點，利用目視觀察法(Visual observation)與掉落式陷阱法(Pitfall trap)，以對環境高度敏感且可穩定生態系食物鏈的昆蟲綱與蛛形綱動物作為目標來進行物種調查，並分析、歸納各屋頂的環境屬性，包括外部環境屬性—周邊建物平均高度、周邊綠覆率，以及內部環境屬性—綠化面積、綠屋頂樓高、綠屋頂綠化年資、植栽種類及其是否正值花期等。物種調查結果將計算成物種豐度、物種歧異度與物種均勻度等生物多樣性指數，討論不同環境屬性的綠屋頂與物種組成之關聯。 研究結果顯示，綠屋頂的綠化面積對物種豐富度與物種豐度有正面影響，但對物種均勻度有負面影響；綠屋頂樓高對物種豐富度、物種豐度與物種歧異度有正面影響；屋頂的綠化年資則對物種豐富度、物種豐度與物種歧異度有負面影響。植栽的豐富度、正值花期之植栽的豐富度皆對物種豐富度、物種豐度具正向影響。外部半徑100公尺內的周邊建物平均高度則對物種豐富度、物種豐度具正面影響。而外部半徑200公尺內的周邊綠覆率則對物種均勻度、物種歧異度有正面影響。

Following the expansion of human activities and developments, the developed land of urban gray infrastructure, various structures, and roads continue to expand. These huge building volumes and paved areas have caused habitat fragmentation that has disturbed the distribution, survival, and breeding of the urban species. In recent decades, the progressing green roof technology has brought multiple functions, such as increasing the area of urban green space, reducing the surface runoff of buildings, thermal insulation, cooling, and energy-saving. Furthermore, from the perspective of landscape ecology, the green roof can provide shelter, habitat, and movement for the species living in the city, forming ecological stepping stones in the city, and improving biodiversity to promote a sound urban ecosystem. However, due to its location on the building, the extent of the biodiversity benefit still depends on the physical environmental attributes such as the building height, the surrounding green space, and the nearby environment of the building. The result would also vary based on the greening area and the age of the green roof. This study sampled eight sites from two programs of the Low Carbon Community Development Division of New Taipei City Environmental Protection Department which take place once to twice a season from October 2019 to June 2020. Visual observation and pitfall-trap method were used to sample insects (Insecta) and spiders (Arachnida, Araneae)–which are keenly sensitive to the environment and able to stabilize the food chain in an ecosystem–as the target species. Meanwhile, the environmental attributes of each sample area, including external environmental attributes: the average height of surrounding buildings, the surrounding green coverage ratio, and the internal environmental attributes: the greening area, location height, green roof age, and plant richness would also be analyzed and summarized. The results of this survey would then turn into biodiversity indices like species abundance, species diversity, and species evenness, facilitating the analytics and discussions of the relationship between different environmental attributes and species composition of the green roof. The purpose of this study is to understand the species distribution of different green roofs in the city and to explore the relationships between various environmental factors of the green roof and the distribution of species, which will benefit the future green roof installation and distribution suggestion for ecological-based urban planning and green roof promotion.