- 學位論文
哈盆溪多齒新米蝦(Neocaridina denticulata)棲地利用之研究
Habitat Use of Freshwater shrimps Neocaridina denticulata in the Hapen Creek
摘要
摘要 棲地利用的研究能瞭解物種的需求及生理限制，並能更進一步瞭解該物種與其他生物的關係及交互作用，並能對保育及經營管理提出建議，多齒新米蝦是臺灣溪流中常見的物種，在淡水生態系中擔任重要的能量傳遞者，並在水族業中具重要經濟價值。為了瞭解哈盆溪多齒新米蝦棲地利用之情形，本實驗在非生殖季（一月）和生殖季（五月）期間，使用鋁製籠具及電擊法於自然與整治河段捕捉多齒新米蝦，並在採樣前後測量該樣點的十四項環境因子，藉此瞭解（1）多齒新米蝦數量和出現率在不同河段和季節的差異；（2）多齒新米蝦於十四項環境因子的棲地利用；（3）不同性別和年齡之個體間棲地利用之差異。 在實驗期間，自然河段有水蘊草而整治河段沒有水蘊草的存在，比較無水蘊草的自然河段與整治河段，發現無論是數量或出現率都沒有顯著差異，然而，在有水蘊草存在的自然河段之多齒新米蝦數量與出現率則較整治河段高，顯示哈盆溪可能因為整治工程影響了底質的型態，導致水蘊草不易生長，進而影響多齒新米蝦的數量及出現率；在季節方面，結果顯示，不同季節在數量和出現率上都有顯著差異，而此差異是因為幼蝦在生殖季大量加入族群所致。由Mann-Whitney U test及多變數變方分析顯示，多齒新米蝦出現在具有水蘊草、遮蔽度較高、水速較慢、水深較淺及樣點外一公尺處底石多樣性較低的棲地，而選擇這些棲地類型可能和躲避掠食者、棲地異質性、生理限制與食物資源有關。另外，在本研究中顯示不同性別和年齡的個體之棲地利用沒有差異，可能是因為其棲地選擇的確沒有差異，亦可能是因為綜合性的因素造成的抵銷，因此不同性別和年齡個體之棲地選擇偏好需要進一步的實驗釐清。
並列摘要
Information on habitat use can enhance our understanding to a species’ecological requirements and physiological costraints, then we can make relevant suggestions about conservation and management. Neocaridina denticulata is a very common shrimp speices in Taiwan streams. They play an important role in freshwater ecosystem and an economical species in aquaculture. To understand hibitat use of Neocaridina denticulata, we use electric fishing method to capture shrimps in natural and altered banks of Hapen creek in both non-reprodective ㄈ and reproductive season (May). The aim of the stury is to understand (1) differences in abundance and distribution of shrimps in different seasons and habitat types, (2) habitat use of shrimps along 14 environmental factors, (3) differences in habitat use among different age/sex groups. During the study period, we found that plants were present only in natural creek banks, but not altered ones. Comparisons between natural banks without plants and altered banks revealed no significant difference in both shrimp abundance and distribution. However, there was significant difference in shrimp abundance when natural banks with plants and altered banks were compared, suggesting that construction might have negative effects on plants and, in turm, on shrimp abudance. Comparisons between reproductive and non-reproductive season yielded significant results in both shrimp abundance and distribution, which resulted from the recruitment of juveniles to local populations. Results of habitat use along 14 environmental factors showed that Neocaridina denticulata appeared at sites with plants, greatrer coverage above water, lower water speed, shallower depths and lower substrate diversity 1m apart. We suggested that sites with the above property serve as shelters against predators, provide more heterogeneous microhabitat and more food. In addition, this study showed that different age/sex groups did not differ in habitat use. Manipulative experiments are needed to further elucidate habitat preference for different age/sex groups.