近年來，雖然已經可以利用eDNA偵測法以得知水生生物的存在與否，且進一步量化其eDNA濃度，並且結合生物量(Biomass)資訊能夠估計族群豐度及密度。但精確的估計物種分佈受到複雜的環境變異所影響，特別是水生生態系統，受到流量及流速而有eDNA擴散和稀釋等問題，因此現階段於eDNA濃度精確估計上仍有許多待釐清的問題要解決。
為了更能夠了解水文特性與環境參數對於eDNA濃度變化的影響，本研究利用eDNA法以得知外來入侵種─小盾鱧之eDNA濃度。於曾文水庫進行兩次不同水文條件之採樣，採集表層、水深10m與水深20m之水樣以探討小盾鱧eDNA垂直濃度變化之情形；另外在南化水庫採集表層水以了解小盾鱧於南化水庫之eDNA濃度分佈；亦在南化水庫下游之後堀溪採集水樣以探討小盾鱧入侵溪流之情況。並且量測環境因子以得知環境變異對於eDNA濃度的影響。希望以不同的面向與觀點，將eDNA視為溶質進而探討其分佈。
從eDNA濃度分佈結果得知，曾文水庫於6日無降雨的條件下，以水深10m之eDNA濃度為最高，次之為水深20m之eDNA濃度，表層水為最低；而降雨後之eDNA濃度分佈呈現均一化且eDNA濃度明顯降低之情形。南化水庫之小盾鱧eDNA濃度分佈以水庫中游為最高，水庫上游靠近溪流出水口處為最低，甚至沒有偵測到小盾鱧eDNA濃度。後堀溪eDNA濃度分佈之情形多集中於後堀溪下游靠近曾文溪匯流口之點位，其中北寮橋不僅有偵測到小盾鱧eDNA，亦有文獻資料證明在此樣點捕捉到。透過Mann-Whitney U檢定、獨立樣本T檢定以及主成分分析的結果得知影響曾文水庫之環境因子為濁度、導電度、硝酸鹽與葉綠素a；影響南化水庫之環境因子則是溶氧、導電度、濁度與葉綠素a；後堀溪則沒有發現環境因子有其顯著性差異。結果顯示曾文水庫受到許多支流流入之逕流影響嚴重，造成環境因子的分佈情形與南化水庫大不相同，亦間接影響小盾鱧eDNA濃度分佈。說明了環境影響對於eDNA濃度在精確估計上的重要性。
本研究的結果顯示降雨造成的地表逕流會使水庫水體混合，使得eDNA濃度受到擾動而有均一化且變少的現象。另一方面，當水體受到擾動時，eDNA會受到外力作用影響，使較大的eDNA裂解且變小，因而增加eDNA受到溫度、UV-B與微生物等影響之表面積，加速eDNA在水中的降解以及移除率。綜合上述，本研究建議採樣時間於連續7日無降雨後，採樣得到的eDNA濃度與分佈較精確。

In order to understand environmental parameters and hydrological influence on eDNA concentration, this study conducted eDNA technology to investigate Channa micropeltes, an invasive species, eDNA concentration. Our study areas include TsengWen Reservoir, NanHua Reservoir and HouJue River. We sampled Channa micropeltes eDNA concentration in all study areas besides TsengWen Reservoir where we investigated different water depth based on two different hydrological conditions. We discovered eDNA concentration in TsengWen Reservoir demonstrated the higest value in 10 m water depth, and lowest value in surface water. The eDNA concentration decreased and distribution was uniformed after rainfall caused runoff disturbing water in the reservoir. In addition, the eDNA concentration distributed higher value at middle section in NanHua Reservoir and downstream of HouJue River.

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