The Great Salt Lake Ecosystem (Utah, USA): long term data and a structural equation approach
The Great Salt Lake Ecosystem (Utah, USA): long term data and a structural equation approach
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DOI：
10.1890/es10-00091.1
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发表时间：
2011-03
期刊：
影响因子：
2.7
通讯作者：
G. Belovsky;D. Stephens;C. Perschon;P. Birdsey;Don S. Paul;D. Naftz;R. Baskin;Chad A. Larson;Chad Mellison;John Luft;Ryan Mosley;Heidi K. Mahon;J. V. Leeuwen;D. Allen
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文献类型：
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作者：
G. Belovsky;D. Stephens;C. Perschon;P. Birdsey;Don S. Paul;D. Naftz;R. Baskin;Chad A. Larson;Chad Mellison;John Luft;Ryan Mosley;Heidi K. Mahon;J. V. Leeuwen;D. Allen
大盐湖（美国犹他州）是世界上最大的高盐湖泊之一，支撑着美国西部的许多地区。迁徙的水鸟。这种独特的生态系统受到威胁，但它和其他大型高盐度湖泊还没有得到很好的了解。该生态系统由两个联系较弱的食物网组成：一个以植物浮游生物为基础，另一个以有机颗粒/底栖藻类为基础。十七年的数据，基于植物的食物网：丰富的营养物质（N和P），浮游植物（绿藻门，硅藻门，蓝藻门），卤虫（卤虫franciscana），corixids（Trichocorixa verticalis），和耳Grebes（Podiceps nigricollis）。还介绍了有机颗粒/底栖藻类食物网中不太常见的物种以及卤蝇幼虫（灰叶蝉和海蝇）的丰度。非生物参数进行了监测：湖泊海拔，温度，盐度，PAR，光穿透，和DO。我们使用这些数据来测试假设phytobacteriston为基础的食物网和它的弱联系的有机颗粒/底栖藻类为基础的食物网通过结构方程模型。与普遍看法相反，以浮游植物为基础的食物网并不受高盐度的限制，而是主要通过浮游植物的生产，而浮游植物的生产则受到氮和卤虫放牧的限制。每年的氮丰度是高度可变的，取决于湖泊体积，复杂的混合给定的温跃层和化学跃层，并通过卤虫回收。盐水虾是食物有限的，和捕食corixids和耳Grebes不会减少他们的数字。耳的数量似乎受到盐水虾丰度的限制。最后，盐水蝇幼虫通过竞争与盐水虾，或通过捕食与corixids或grebes几乎没有相互作用，这表明湖泊的两个食物网是弱连接的。结果被用来检查一些一般概念的食物网结构和动态，以及湖泊的未来预期的人为影响。
Great Salt Lake (Utah, USA) is one of the world's largest hypersaline lakes, supporting many of the western U.S.'s migratory waterbirds. This unique ecosystem is threatened, but it and other large hypersaline lakes are not well understood. The ecosystem consists of two weakly linked food webs: one phytoplankton-based, the other organic particle/benthic algae-based. Seventeen years of data on the phytoplankton-based food web are presented: abundances of nutrients (N and P), phytoplankton (Chlorophyta, Bacillariophyta, Cyanophyta), brine shrimp (Artemia franciscana), corixids (Trichocorixa verticalis), and Eared Grebes (Podiceps nigricollis). Abundances of less common species, as well as brine fly larvae (Ephydra cinerea and hians) from the organic particle/benthic algae-based food web are also presented. Abiotic parameters were monitored: lake elevation, temperature, salinity, PAR, light penetration, and DO. We use these data to test hypotheses about the phytoplankton-based food web and its weak linkage with the organic particle/benthic algae-based food web via structural equation modeling. Counter to common perceptions, the phytoplankton-based food web is not limited by high salinity, but principally through phytoplankton production, which is limited by N and grazing by brine shrimp. Annual N abundance is highly variable and depends on lake volume, complex mixing given thermo- and chemo-clines, and recycling by brine shrimp. Brine shrimp are food-limited, and predation by corixids and Eared Grebes does not depress their numbers. Eared Grebe numbers appear to be limited by brine shrimp abundance. Finally, there is little interaction of brine fly larvae with brine shrimp through competition, or with corixids or grebes through predation, indicating that the lake's two food webs are weakly connected. Results are used to examine some general concepts regarding food web structure and dynamics, as well as the lake's future given expected anthropogenic impacts.