Evaluating How Soil and Plants Affect the Damselfly Mortonagrion hirosei in Huang Gang Creek in Taipei

• Main Authors: Yi-Hsuan Fan, 范倚瑄
• Other Authors: Wen-Lian Chang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/3r64e5

碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 106 === Mortonagrion hirosei is a damselfly species which has been categorized as “near threatened” in IUCN red list. In Taiwan, it has only been found in three wetlands along the downstream of Tamsui River, and Huang Gang Creek estuary is one of them. However, recently this habitat has experienced large-scale bridge construction; the living condition of M.hirosei under human disturbance, therefore, requires special concerns. This study analyzes the correlation between M.hirosei’s density and environmental factors including water, soil, plants, and microclimate. A decrease of 44.8% vegetation coverage is found, restricting the distribution of M.hirosei. A major factor is the increase of wind speed, which used to be lowered by plantation, these two landscape elements turned out to be crucial for maintaining its habitat. An extremely acid water quality (pH < 3) is found as an asset of this estuary. Particularly, reeds with a density of 200 to 500 branches/m2 are found most favorable. Temperature and light intensity are observed as important environment factor of reed density. Soil organic matters dominate the soil heterogeneity, which also presents a significantly positive correlation with reed density. Finally, this study suggests that human should consider the cause of habitat loss and fragmentation by reed destroyed in estuary development, and emphasis on preserve soil organic matters to maintain proper reed density.