CSIRO Water for a Healthy Country National Research Flagship, GPO Box 1700, Canberra, ACT 2601, Australia.
Mol Ecol. 2010 Jan;19(1):197-212. doi: 10.1111/j.1365-294X.2009.04411.x. Epub 2009 Nov 11.
Determining the source and flow of carbon, energy and nutrients through food webs is essential for understanding ecological connectivity and thus determining the impact of management practices on biodiversity. We combined DNA sequencing, microarrays and stable isotope analyses to test whether this approach would allow us to resolve the carbon flows through food webs in a weir pool on the lower Murray River, a highly impacted, complex and regulated ecosystem in southern Australia. We demonstrate that small fish in the Murray River consume a wide range of food items, but that a significant component of carbon and nitrogen entering the food web during dry periods in summer, but not spring, is derived from nonconventional sources other than in-channel primary producers. This study also showed that isotopic analyses alone cannot distinguish food sources and that a combined approach is better able to elucidate food-consumer dynamics. Our results highlight that a major river ecosystem, stressed by reduced environmental flows, can rapidly undergo significant and previously undetected changes that impact on the ecology of the system as a whole.
确定食物网中碳、能量和养分的来源和流动对于理解生态连通性至关重要，从而确定管理实践对生物多样性的影响。我们结合 DNA 测序、微阵列和稳定同位素分析，以测试这种方法是否能够确定在澳大利亚南部高度受影响、复杂和受管制的莫累河下游堰池食物网中的碳流。我们证明，莫累河里的小鱼消耗了广泛的食物，但在夏季干旱期进入食物网的大量碳和氮的一部分并非来自于河道内的初级生产者，而是来自非传统来源。这项研究还表明，仅同位素分析无法区分食物来源，而综合方法更能够阐明食物消费者的动态。我们的研究结果强调了一个主要的河流生态系统，在减少的环境流的压力下，可能会迅速经历重大且以前未被发现的变化，从而影响整个系统的生态。
