کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6305544 | 1618570 | 2015 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Variation in diet across an elevational gradient in the larvae of two Hydropsyche species (Trichoptera)
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
علوم آبزیان
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
While specialized species are linked to a particular resource, omnivorous species may switch between food items according to the availability and the quality of resources. Here we use larvae of the omnivorous caddisfly genus Hydropsyche (Trichoptera) to analyse changes in diet composition across an elevational gradient. Periphyton and Hydropsyche larvae were sampled from 22 populations at stream orders from 2 to 5 on the German part of the Bohemian Forest. Elevations of sampling sites ranged between 300 m and 900 m a.s.l.. Diet composition was estimated by the analyses of the gut content of larvae as well as by stable nitrogen isotopes (δ15N). The δ15N values of the periphyton decreased and the C/N ratio of periphyton increased with increasing environmental harshness (decreasing water pH, temperature and conductivity with increasing elevation) indicating a decrease of periphyton food quality. Across individuals, the proportion of animals in the gut of Hydropsyche larvae was positively related to the difference of δ15N values between larvae and periphyton. The proportion of animals within the gut and (baseline corrected) δ15N values of Hydropsyche populations increased with increasing environmental harshness. We suggest that the (i) low primary production caused by shading, low temperatures and low nutrient levels, (ii) the low nutrient quality of periphyton and (iii) the availability of animal prey due to the input of allochthonous resources in headwaters caused the shift in the diet of Hydropsyche larvae along the river continuum.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Limnologica - Ecology and Management of Inland Waters - Volume 52, May 2015, Pages 83-88
Journal: Limnologica - Ecology and Management of Inland Waters - Volume 52, May 2015, Pages 83-88
نویسندگان
Thomas Bing, Jörg Müller, Bruno Glaser, Roland Brandl, Martin Brändle,