Periphyton responses to invertebrate grazing and riparian canopy in three northern California coastal streams
Periphyton responses to invertebrate grazing and riparian canopy in three northern California coastal streams
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北加州沿海溪流的附生植物对无脊椎动物放牧和河岸冠层的反应
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
V. Resh
中科院分区：
文献类型：
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作者：
J. Feminella;M. Power;V. Resh
摘要1.在北方加州三条海岸溪流（美国）的21个水池中进行了田间试验，以检查放牧无脊椎动物对附着生物生物量的影响：大硫磺溪，鳗鱼河的水稻叉，和大峡谷溪。人工基质瓷砖上的附生植物的积累进行了比较，在每个流之间的两个治疗：那些抬高略高于流底部，以减少访问的食草动物（=平台）和那些直接放置在流底部，以允许访问的食草动物（=控制）。
2.爬行无脊椎动物食草动物（套石蛾和蜗牛）在每个流（86%的所有食草动物在大硫磺溪，61%的水稻叉，84%的大峡谷溪）的数量占主导地位。平台有效地排除爬行食草动物，但不太有效地排除游泳蜉蝣食草动物（Baetidae）。
3.瓷砖上的附生植物生物量（AFDM）显着低于对照组相比，平台的水稻叉，一个开放的树冠流，和大硫溪，流与异质树冠。相比之下，没有发现大峡谷溪，一个密集的阴影流食草动物的影响。在这里，在整个60天的研究中，两种处理都发生了极低的附着生物生物量。
4.河岸冠层的影响，对附着生物的增长（即平台上的收益），食草动物对附着生物的影响，和食草动物的丰度进行了检查大硫溪。随着林冠的增加（15-98%覆盖），平台上的附着生物量减少。相比之下，树冠上的控制附着生物积累的影响不大，显然，食草动物可以保持低附着生物在整个范围内的冠层水平的作物。丰富的一个食草动物物种，石蛾Gumaga nigricula，是最高的开放，阳光普照的流池;丰富的其他两个突出的食草动物，Helicopsyche borealis（毛翅目）和Centroptilum convexum（蜉蝣目），然而，是无关的树冠。
SUMMARY. 1. Field experiments were conducted to examine the impact of grazing invertebrates on periphyton biomass in twenty-one pools across three northern California coastal streams (U.S.A.): Big Sulphur Creek, the Rice Fork of the Eel River, and Big Canyon Creek. Periphyton accrual on artificial substrate tiles was compared in each stream between two treatments: those elevated slightly above the stream bottom to reduce access by grazers (= platforms) and those placed directly on the stream bottom to allow access by grazers (=controls).
2. Crawling invertebrate grazers (cased caddisflies and snails) were numerically dominant in each stream (86% of all grazers in Big Sulphur Creek, 61% in the Rice Fork, 84% in Big Canyon Creek). Platforms effectively excluded crawling grazers, but were less effective in excluding swimming mayfly grazers (Baetidae).
3. Periphyton biomass (as AFDM) on tiles was significantly lower on controls compared to platforms for the Rice Fork, an open-canopy stream, and Big Sulphur Creek, a stream with a heterogeneous canopy. In contrast, no grazer impact was found for Big Canyon Creek, a densely shaded stream. Here, extremely low periphyton biomass occurred for both treatments throughout the 60 day study.
4. The influence of riparian canopy on periphyton growth (i.e. accrual on platforms), grazer impact on periphyton, and grazer abundance was examined for Big Sulphur Creek. As canopy increased (15–98% cover), periphyton biomass on platforms decreased. In contrast, canopy had little influence on periphyton accrual on controls; apparently, grazers could maintain low periphyton standing crops across the full range of canopy levels. The abundance of one grazer species, the caddisfly Gumaga nigricula, was highest in open, sunlit stream pools; abundance of two other prominent grazers, Helicopsyche borealis (Trichoptera) and Centroptilum convexum (Ephemeroptera), however, was unrelated to canopy.