立場新聞 Stand News

【后海灣一分鐘】九、誰在善用塘壆?誰在利用塘壆?

2020/2/14 — 15:59

塘壆是魚塘養殖和后海灣濕地生態系統中不可或缺的一部份。漁民會用生長在塘壆的草餵飼鯇魚,塘壆也是一些水鳥的庇護所,為捕獵昆蟲或啄食種子的雀鳥如鶯、鵐和鷚等提供食物。「后海灣地區魚塘生態價值研究」 (1997) 曾比較在四種不同塘壆生境裡所錄得的陸生無脊椎動物,結果顯示灌木叢擁有最豐富的物種數目,蘆葦床錄得最高的個體密度,而草地則有最高的生物質 (biomass) 。光禿禿的塘壆縱使擁有最低的陸生無脊椎動物物種數目和生物質,但卻為鷺鳥如小白鷺、大白鷺及黑臉琵鷺等提供合適的晚棲地。因此,有植被及沒有植被的塘壆在后海灣濕地生態系統中均有其獨特的生態功能及角色。

然而,為了迎合城市規劃委員會規劃指引的「不會有濕地淨減少 (no-net-loss in wetland) 」原則,發展商提出移除塘壆以增加水體面積,作為補償因填土興建樓宇所帶來的濕地損失。漁農自然護理署曾就南生圍的房地產發展項目(規劃申請編號 A/YL-NSW/218)指出發展商所謂的「不會有濕地淨減少」「只計算了發展前後『水體面積』上的差異,而沒有考慮到其大範圍的發展面積和所帶來的生態影響…若然計算現有濕地面積時沒有納入塘壆,將會低估濕地損失的面積。」豐樂圍濕地的房地產發展項目申請亦採用同樣策略,最終卻獲得城市規劃委員會批准興建樓宇,此事件亦促使有環保團體就此提出司法覆核。香港觀鳥會認為發展商就「不會有濕地淨減少」的計算方式有誤導,因此不能接受。

想知更多【后海灣一分鐘】

廣告

延伸閱讀:
「共享土地先導計劃」改名換姓 助地產商開發「候鳥天堂」
反對犧牲「濕地緩衝區」以換取后海灣濕地保育

*  *  *

廣告

【Deep Bay in a Minute】 9. Pond bunds: an ecological fabric or a development tactic?  

Pond bunds are an integral part of the fishpond operation and the Deep Bay wetland ecosystem. For example, fish farmers use the grass grown at the pond bunds to feed the Grass Carp in the fishponds. Besides, the vegetated bunds serve as a shelter for water birds and provide alternative food sources to insect- and seed- feeding birds such as warbler, buntings and pipits. A preliminary investigation was conducted for terrestrial invertebrates in four vegetation types on pond bunds under the “Study on the Ecological Value of Fishponds in the Deep Bay Area (1997)”. It was found that scrub has the highest taxa richness, reed held the greatest density of individuals, grass has the highest biomass, while bare ground held the lowest in count and biomass of invertebrates among them all. However, from our observation, un-vegetated fishpond bunds also provide roosting habitat for ardeids such as Little Egrets, Great Egrets, and Black-faced Spoonbills. Therefore, both vegetated and un-vegetated fishpond bunds have their own ecological functions in the Deep Bay wetland ecosystem. 

In order to meet the Deep Bay planning principle of “no-net-loss in wetland”, developers have tried to remove pond bunds so as to increase the “wetland” area (i.e. water surface of fishponds) to compensate the wetland loss caused by the development. AFCD commented on the previous Nam Sang Wai development (planning application no. A/YL-NSW/218), saying that so-called “no-net-loss in wetland” claimed by the developer “only calculated the difference in area of ‘water surfaces’ before and after development without considering the extensive development area and its ecological impact…omission of the pond bunds in the calculation of the existing wetland area would underestimate the area of wetland loss.” Similar tactic was used in Fung Lok Wai wetland, leading to an environmental NGO to launch a judicial review against the Town Planning Board’s approval of the residential development in the locality. HKBWS considers that such “no-net-loss in wetland” calculation method is unacceptable and misleading.

Know more about 【Deep Bay in a Minute】

發表意見