Consumption of aquatic bryophytes by alpine stream invertebrates in New Zealand
作者:
AlastaerM. Suren,
MichaelJ. Winterbourn,
期刊:
New Zealand Journal of Marine and Freshwater Research
(Taylor Available online 1991)
卷期:
Volume 25,
issue 3
页码: 331-343
ISSN:0028-8330
年代: 1991
DOI:10.1080/00288330.1991.9516487
出版商: Taylor & Francis Group
关键词: aquatic bryophytes;invertebrates;feeding;bryophagy;stable carbon analysis;autochthonous;allochthonous;food value;antiherbivore compounds
数据来源: Taylor
摘要:
Gut contents of 23 invertebrate taxa that dwell among bryophytes in two small New Zealand alpine streams with different riparian vegetation were examined. Bryophyte fragments were found in guts of 14 taxa, but only the tipulidLimonia hudsoniand the oeconesid caddisfliesZelandopsyche ingensandOeconesus similiscommonly consumed bryophytes. Bryophyte‐dwelling animals consumed more periphyton at the unshaded site or riparian vegetation at the shaded site than did animals dwelling amongst gravels. Stable carbon isotope ratios were compared between selected animals and plants, and indicated that animals in the unshaded site relied primarily on autochthonous detritus, whereas animals from the shaded site relied on allochthonous detritus. An indication of the food value of five bryophytes(Fissidens rigidulus, Cratoneuropsis relaxa, Bryum blandum, Plagiochila retrospectans, andHepa‐tostolonophora paucistipula)and of seven common riparian plants(Chionochloa pallens, C. flavescens, Hebe subalpina, H. odora, Nothofagus solandrivar.cliffortioides, Blechnum capense, andMarsippo‐spermum gracile)was obtained by comparing their proximate biochemical composition. This revealed that bryophytes contained more refractory and indigestible compounds than riparian plants and represented a less nutritious food source for animals. Avoidance of bryophyte tissues thus reflects a combination of the presence of alternative foods and their low nutritional value; bryophytes may also contain antifcedant compounds.
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