The relationship between farm pond management and odonate biodiversity

• Main Authors: Wen-Chieh Chien, 簡雯潔
• Other Authors: Mei-Hui Li
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/74228324486362256682

碩士 === 國立臺灣大學 === 地理環境資源學研究所 === 104 === The objective of this study was to assess the relationship between farm pond management and odonate biodiversity. Twenty-four farm ponds are selected for this study and classified into five categories according to their pond management practices, including (1) fish farming ponds, (2) fish farming ponds with a path surrounding the pond, (3) fish farming ponds for recreational fishing, (4) ecology park ponds, and (5) abandoned ponds. Adult odonate biodiversity and environmental characteristics of farm ponds including water quality, pond structure and landscape variables were investigated during June 2014 to July 2015, and the weather condition of each farm pond was recorded during the investigation period. Simpson’s index (1-D) and Shannon-Wiener’s index were calculated for ondonate biodiversity. Kruskal-Wallis test, Mann-Whitney U test, general linear model, Spearman rank correlation, analysis of similarity, BIO-ENV analysis and canonical correspondence analysis were applied to examine effects of environmental factors of farm ponds on odonate biodiversity. Environmental characteristics of farm ponds and odonate biodiversity varied significantly with different farm pond management based on the results of Kruskal-Wallis test and Mann-Whitney U test. In particular, water qualities of farm ponds, such as pH, conductivity, and dissolved oxygen, are relatively high in all three fish farming ponds compared to ecology park ponds and abandoned ponds. These difference of pond water conditions may be due to aquaculture activitiesat fish farm ponds, because pond fertilization and input of fish feed resulted in eutrophication. As for pond physical structures, three categories of fish farming ponds all have concrete embankment with only terrestrial vegetation. Ecology park ponds have natural embankment with both aquatic and terrestrial vegetation. Abandoned ponds have mixed types of embankments. Among five classes of farm ponds, odonate biodiversity are the lowest in the fish farming ponds with a path surrounding the pond and are the highest in ecology park ponds. Landscape variables only showed significantly difference at the 1600-meter buffer range by using general linear model analysis. In addition, geographical location and number of ponds within the buffer range may be the reason to explain why fish farming ponds for recreational fishing can have higher odonate biodiversity than other fish farming ponds. Interestingly, pond sizes showed significant negative correlation with odonate biodiversity based on the results of Spearman rank correlation, BIO-ENV analysis and canonical correspondence analysis. The result of this study further suggested that pond size may be not as important as pond management to odonate biodiversity conservation. The most prominent factor contributing to odonate biodiversity and species composition is the presence of different vegetation types, because the survivals of odonates rely on not only riparian plants but also aquatic plants including emergent plants and floating plants. The second important factor is conductivity of pond water. Therefore, ecology park ponds with diverse vegetation types have the highest odonate biodiversity among five classes of ponds. This study shows that farm pond management can affect the environmental characteristics of pond ecosystems, and thus influence the odonate biodiversity. Farm ponds can host high biodiversity as long as pond management practices are considered both local pond habitat preservation and large landscape-scale pond conservation.