Tropical Rivers and Coastal Knowledge (TRaCK), Australian Rivers Institute, Griffith University, Nathan, Queensland 4111, Australia.
J Fish Biol. 2010 Aug;77(3):731-53. doi: 10.1111/j.1095-8649.2010.02712.x.
This article examines the trophic ecology of freshwater fishes (22 species in 15 families) in a wet and dry tropical Australian river of high intra-annual and interannual hydrological variability. Seven major trophic groups were identified by cluster analysis; however, four food items (filamentous algae, chironomid larvae, Trichoptera larvae and Ephemeroptera nymphs) comprised almost half of the average diet of all species. The influence of species, fish size, spatial effects and temporal effects on food use was investigated using redundancy analysis. Size, time and space accounted for little of the perceived variation. Ontogenetic changes in diet were minor and limited to a few large species. Spatial variation in trophic composition of the fish assemblages reflected the effects of the Burdekin Falls and dam, a major geographic barrier, on species distributions. Little spatial variation in diet was detected after accounting for this biogeographical effect. Temporal variations in flow, although marked, had little effect on variations in fish diet composition due to the low temporal diversity of food resources in physically monotonous sand and gravel channels. Species identity accounted for<50% of the observed variation in food choice; omnivory and generalism were pronounced. The aquatic food web of the Burdekin River appears simple, supported largely by autochthonous production (filamentous and benthic microalgae, and to some extent, aquatic macrophytes). Allochthonous food resources appear to be unimportant. The generalist feeding strategies, widespread omnivory and absence of pronounced trophic segregation reported here for Burdekin River fishes may be common to variable and intermittent rivers of subtropical and tropical northern Australia with similar fish communities and may be a general feature of rivers of low habitat diversity and characterized by flow regimes that vary greatly both within and between years.
本文研究了澳大利亚干湿热带一条高年内和年际水文学变异性的河流中淡水鱼类（15 科 22 种）的营养生态。通过聚类分析确定了七个主要营养类群；然而，四种食物（丝状藻类、摇蚊幼虫、蜉蝣幼虫和蜉蝣若虫）几乎占所有物种平均饮食的一半。使用冗余分析研究了物种、鱼类大小、空间效应和时间效应对食物利用的影响。大小、时间和空间仅占感知到的变异的一小部分。饮食的发育变化很小，仅限于少数大型物种。鱼类群落的营养组成的空间变化反映了 Burdekin Falls 和大坝（一个主要的地理屏障）对物种分布的影响。在考虑到这种生物地理效应后，发现鱼类饮食的空间变化很小。尽管流量变化明显，但由于物理单调的沙砾通道中食物资源的时间多样性较低，因此对鱼类饮食组成的变化影响不大。物种身份仅解释了食物选择中观察到的变异的<50%；杂食性和广食性很明显。Burdekin 河的水生食物网似乎很简单，主要由自生生产（丝状和底栖微藻，在某种程度上还有水生植物）支持。异源食物资源似乎不重要。这里报道的 Burdekin 河鱼类的普遍杂食性、广泛的杂食性和缺乏明显的营养隔离策略可能在澳大利亚亚热带和热带地区具有类似鱼类群落的变化不定和间歇性河流中很常见，并且可能是低生境多样性河流的普遍特征，其特点是年内和年际之间的流量变化很大。
