Changes in mercury bioaccumulation in an apex predator in response to removal of an introduced competitor
Changes in mercury bioaccumulation in an apex predator in response to removal of an introduced competitor
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DOI：
10.1007/s10646-009-0306-5
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发表时间：
2009-07-01
期刊：
影响因子：
2.7
通讯作者：
Josephson, Daniel C.
中科院分区：
文献类型：
--
作者：
Lepak, Jesse M.;Robinson, Jason M.;Josephson, Daniel C.
我们评估了甲基汞（MeHg）浓度在本地的顶级捕食者，湖鳟纳迈库什之前和之后的大规模删除引进的捕食者，小口鲈鱼Micropterus的在一个270公顷的阿迪朗达克湖。以前的研究表明，去除竞争对手可以增加生长，降低剩余鱼类中的汞浓度。相反，我们观察到一个显着增加湖鳟鱼甲基汞浓度，尽管观察到湖鳟鱼的增长。生物能量学模拟预测湖鳟体内甲基汞浓度也会出现类似的增加。相对于无脊椎动物（去除前饮食），猎物鱼（去除后饮食）中较高的甲基汞是增加湖鳟甲基汞浓度的最重要因素。然而，这种影响被增加的湖鳟鱼生长所抵消（即，生长稀释）可能是由于觅食成本降低和猎物能量密度增加的组合。这些数据为食物网结构的变化可影响顶级捕食者体内甲基汞浓度的机制（由于竞争减少而改变饮食）提供了证据。
We evaluated methylmercury (MeHg) concentrations in native apex predators, lake trout Salvelinus namaycush before and after the large-scale removal of introduced predators, smallmouth bass Micropterus dolomieu in a 270 ha Adirondack lake. Previous studies show that removing competitors can result in increased growth and decreased mercury concentrations in remaining fish. Instead, we observed a significant increase in lake trout MeHg concentrations despite observed increases in lake trout growth. Bioenergetics simulations predicted similar increases in lake trout MeHg concentrations. Higher MeHg in prey fish (post-removal diet) relative to invertebrates (pre-removal diet) was the most important factor increasing lake trout MeHg concentrations. However, this effect was counteracted by increased lake trout growth (i.e., growth dilution) likely due to a combination of decreased foraging costs and an increase in prey energy density. These data provide evidence for a mechanism (diet shift due to reduced competition) by which changes in food web structure can influence MeHg concentrations in top predators.