金門佛法僧目鳥類調查(三)
一、研究緣起與目的
本年度研究承續2006年的研究成果,分別利用野外調查和分子生物學技術,探討金門地區戴勝的巢位選擇、子代性別差異、遺傳婚配制度(genetic mating system)及族群結構等議題。研究緣起係因為在2006年的研究中,發現當年繁殖的戴勝幼鳥雌性顯著多於雄性;有些配對繁殖的戴勝巢洞洞口會有其他成鳥活動,甚至曾經發現擁有巢洞的母鳥會和配偶外的雄鳥交配。繁殖季結束後,自八月起戴勝會開始成群出現,群的出沒地點並不固定,但自十月起,觀察到的戴勝數量突然大量減少。在繁殖季出現的戴勝(包括成鳥和當年繁殖的幼鳥)在繁殖季後都沒再被發現。基於上述發現,本研究的具體研究目的包括:分析影響戴勝巢位空間分布的因子、持續收集戴勝的繁殖資料、分析戴勝幼鳥的性別比例差異、篩選具多型性的遺傳標記,進行戴勝的親子鑑定及族群結構分析等,並根據研究成果及調查過程中所發現的狀況提出對戴勝保育及經營管理的建議。
二、重要發現
本研究發現戴勝巢位之分布與房舍面積及道路面積呈正相關,而和林地面積有負相關,推測可能是因為在房舍或道路附近,人類的活動產生了各類洞穴可供戴勝使用,但樹林區中缺少可形成樹洞的大樹,所以反而少有戴勝繁殖。雖然去年繁殖出的幼鳥之雌雄性別比例為1:0.56,今年的幼鳥之性別比例並沒有明顯偏離1:1。微衛星基因座的多型性測試顯示,在七組基因座中有四個基因座呈現同型結合子過多的現象,可能是由於近親交配所導致。親子鑑定的結果發現,兩年中共有9%的子代是親鳥「偶外交配」所生的。非繁殖季的戴勝族群之遺傳多樣性較繁殖季的族群高,推測應包括了在金門過境的候鳥。
三、主要建議事項
根據本年度的研究成果,研究人員提出以下三項建議:(一)製作戴勝生態解說資料,作為戴勝保育和金門鄉土資源教育解說的材料;(二)監測金門的環境變化,密切注意金門的快速開發行為對自然景觀的衝擊,和對包括戴勝在內的動、植物可能產生的影響。(三)進行戴勝的遺傳監測,每隔五年收集一批繁殖戴勝的遺傳樣本,比較其遺傳多樣性的變化,除可估算其有效族群量外,也可以監測其遺傳多樣性的變動情形。
Abstract
In this study, we combined field observation, geographic information system and molecular techniques to study the spatial factors affecting hoopoe nest site selection, offspring sex ratio, and population genetics of the hoopoe. We found that the appearance of hoopoe nest was positively correlated with the area of surrounding houses and roads, and negatively correlated with the area of woodland. Lack of big trees to provide nest cavities and abundant artificial cavities provide them suitable nesting sites might be the reasons of these correlations.
Molecular sex-typing of 29 juveniles from 12 nests showed that the 16 of them were females and 13 of them were males. The offspring sex ratio was not deviated from 1:1. Microsatellite genotype data revealed that homozygote excess exists in four of seven microsatellite loci, this indicated that the Hoopoe might face the threat of inbreeding. Paternity analysis showed that six juveniles (9%) were born via extra-pair fertilization. Compared with the breeding population, samples collected at nonbreeding season (August and September) showed higher genetic diversity and had more private alleles. This means that they were autumn visitors from places outside the study area with larger population size, Low Fst value between these two populations indicated that the divergence between these two populations is small.
本年度研究承續2006年的研究成果,分別利用野外調查和分子生物學技術,探討金門地區戴勝的巢位選擇、子代性別差異、遺傳婚配制度(genetic mating system)及族群結構等議題。研究緣起係因為在2006年的研究中,發現當年繁殖的戴勝幼鳥雌性顯著多於雄性;有些配對繁殖的戴勝巢洞洞口會有其他成鳥活動,甚至曾經發現擁有巢洞的母鳥會和配偶外的雄鳥交配。繁殖季結束後,自八月起戴勝會開始成群出現,群的出沒地點並不固定,但自十月起,觀察到的戴勝數量突然大量減少。在繁殖季出現的戴勝(包括成鳥和當年繁殖的幼鳥)在繁殖季後都沒再被發現。基於上述發現,本研究的具體研究目的包括:分析影響戴勝巢位空間分布的因子、持續收集戴勝的繁殖資料、分析戴勝幼鳥的性別比例差異、篩選具多型性的遺傳標記,進行戴勝的親子鑑定及族群結構分析等,並根據研究成果及調查過程中所發現的狀況提出對戴勝保育及經營管理的建議。
二、重要發現
本研究發現戴勝巢位之分布與房舍面積及道路面積呈正相關,而和林地面積有負相關,推測可能是因為在房舍或道路附近,人類的活動產生了各類洞穴可供戴勝使用,但樹林區中缺少可形成樹洞的大樹,所以反而少有戴勝繁殖。雖然去年繁殖出的幼鳥之雌雄性別比例為1:0.56,今年的幼鳥之性別比例並沒有明顯偏離1:1。微衛星基因座的多型性測試顯示,在七組基因座中有四個基因座呈現同型結合子過多的現象,可能是由於近親交配所導致。親子鑑定的結果發現,兩年中共有9%的子代是親鳥「偶外交配」所生的。非繁殖季的戴勝族群之遺傳多樣性較繁殖季的族群高,推測應包括了在金門過境的候鳥。
三、主要建議事項
根據本年度的研究成果,研究人員提出以下三項建議:(一)製作戴勝生態解說資料,作為戴勝保育和金門鄉土資源教育解說的材料;(二)監測金門的環境變化,密切注意金門的快速開發行為對自然景觀的衝擊,和對包括戴勝在內的動、植物可能產生的影響。(三)進行戴勝的遺傳監測,每隔五年收集一批繁殖戴勝的遺傳樣本,比較其遺傳多樣性的變化,除可估算其有效族群量外,也可以監測其遺傳多樣性的變動情形。
Abstract
In this study, we combined field observation, geographic information system and molecular techniques to study the spatial factors affecting hoopoe nest site selection, offspring sex ratio, and population genetics of the hoopoe. We found that the appearance of hoopoe nest was positively correlated with the area of surrounding houses and roads, and negatively correlated with the area of woodland. Lack of big trees to provide nest cavities and abundant artificial cavities provide them suitable nesting sites might be the reasons of these correlations.
Molecular sex-typing of 29 juveniles from 12 nests showed that the 16 of them were females and 13 of them were males. The offspring sex ratio was not deviated from 1:1. Microsatellite genotype data revealed that homozygote excess exists in four of seven microsatellite loci, this indicated that the Hoopoe might face the threat of inbreeding. Paternity analysis showed that six juveniles (9%) were born via extra-pair fertilization. Compared with the breeding population, samples collected at nonbreeding season (August and September) showed higher genetic diversity and had more private alleles. This means that they were autumn visitors from places outside the study area with larger population size, Low Fst value between these two populations indicated that the divergence between these two populations is small.