Effects of invasive macrophytes on littoral-zone productivity and foodweb dynamics in a New Zealand high-country lake
Effects of invasive macrophytes on littoral-zone productivity and foodweb dynamics in a New Zealand high-country lake
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入侵大型植物对新西兰高地湖泊沿岸地区生产力和食物网动态的影响
DOI：
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发表时间：
2005
影响因子：
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通讯作者：
I. Hawes
中科院分区：
文献类型：
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作者：
D. Kelly;I. Hawes
摘要 外来大型植物物种入侵沿岸地区可以促进湖泊生态的重大变化。在新西兰的一个大型高山湖泊瓦纳卡湖中，大型植物 Lagarosiphon Major 和 Elodea canadensis (Hydrocharitaceae) 已经侵入了湖的部分区域，在沿岸区域的中深度 (2-7 m) 形成了高而茂密的植物床。我们研究了沿岸带中部深处本地和外来植物床的植物、底栖无脊椎动物、鱼类和食物网的差异。外来植物床中的植物生物量高出 3 倍，植物表面积高出 2 倍（水芹、水仙和轮藻植物），这有助于增加外来植物床中附生植物的立存量和生产力。由于本地和外来植物群落的生物量、生产力和物理结构的差异，本地无脊椎动物群落的密度（1890/m2 vs 4030/m2）和多样性（丰富度= 9 vs 12）低于外来植物床。原生床中的无脊椎动物群落以蜗牛、寡毛类和线虫为主，而摇蚊、蜗牛和石蛾在外来床中占主导地位。稳定同位素特征（13C 和 15N）和饮食分析表明，两种床型中的主要无脊椎动物分类单元 Potamopyrgus antipodarum 消耗的大部分是附生生物。在原生床中，寡毛类和线虫对沉积细小底栖有机物的消耗对碳流做出了重大贡献，而在外来床中，食草动物（例如蜗牛、石蚕和摇蚊）对附生生物的消耗是碳流的重要途径。在这两种床类型中，大型植物对碳流的贡献很小。瓦纳卡湖的主要本地鱼类，霸王鱼，在外来河床中的数量比本地河床中的数量更多，但在外来河床中，霸王鱼对蜗牛的捕食率明显低于本地河床。外来植物物种的入侵可能会导致湖泊生产力、物种组成和食物网动态发生重大变化。
Abstract Invasion of littoral zones by adventive macrophyte species can facilitate major changes in the ecology of lakes. In Lake Wanaka, a large alpine New Zealand lake, the macrophytes Lagarosiphon major and Elodea canadensis (Hydrocharitaceae) have invaded parts of the lake where they form tall dense plant beds throughout mid-depths (2–7 m) of the littoral zone. We investigated differences in plants, benthic invertebrates, fish, and food webs characterizing native and exotic plant beds in mid-depths of the littoral zone. The 3× higher plant biomass and 2× higher plant surface area in exotic than in native plant beds (quillworts, milfoils, and charophytes) contributed to greater standing stocks and productivity of epiphyton in the exotic plant beds. Invertebrate communities were less dense (1890/m2 vs 4030/m2) and less diverse (richness = 9 vs 12) in native than in exotic plant beds because of differences in biomass, productivity, and physical structure of native and exotic plant communities. Invertebrate communities in native beds were dominated by snails, oligochaetes, and nematodes, whereas chironomids, snails, and caddisflies were dominant in exotic beds. Stable isotope signatures (13C and 15N) and dietary analyses indicated that Potamopyrgus antipodarum, the dominant invertebrate taxon in both bed types, consumed mostly epiphyton. In native beds, consumption of sedimentary fine benthic organic matter by oligochaetes and nematodes made significant contributions to C flow, whereas, in exotic beds, consumption of epiphyton by grazers (e.g., snails, caddisflies, and chironomids) was an important pathway for C flow. Macrophytes made only small contributions to C flow in either bed type. The dominant native fish in Lake Wanaka, the bully Gobiomorphus cotidianus, was more abundant in exotic than in native beds, but bully predation rates on snails were significantly lower in exotic than in native beds. Invasion by adventive macrophyte species can cause significant shifts in lake productivity, species composition, and foodweb dynamics.