Evidence for Atmospheric Deposition Impacts On the Enchytraeid Worm Population of Uk Upland Ombrotrophic Peats |
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Authors: | Laila Yesmin E Adsil Fitzpatrick Malcolm S Cresser |
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Institution: |
a Department of Plant and Soil Science, University of Aberdeen, Meston Building, Old Aberdeen, United Kingdom |
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Abstract: | The results of four experiments on acidification effects upon the Enchytraeid worm populations of ombrotrophic peats are reported. in the first, populations were measured in peats from Calluna vulgaris-dominated microcosms collected from along a gradient in N deposition in the UK and subjected for 18 months to simulated precipitation with a solute composition appropriate for their site of collection. There was a significant decline in Enchytraeid population along the N deposition gradient for Calluna-dominant microcosms, but when grasses took over from the Calluna, Enchytraeid numbers increased significantly. in the second experiment, two sets of peat moorland microcosms from a single site, supporting Calluna and Calluna-grass mixed vegetation, were subjected for 12 months to ambient and 2- and 6-times the ambient N deposition. Additional N was added in two forms, as ammonium sulphate and as nitric acid. the high N treatments significantly reduced the Enchytraeid populations for both vegetation types. in a third experiment, the pH preference for the Enchytraeids was assessed using interconnected tubes of peat covering the pH range 2.2-8.7. the preferred pH range after 8 months was 2.7-3.7. in the final experiment, it was found that recolonization with Enchytraeids after initial removal was more rapid under grass dominant vegetation than under Calluna dominant vegetation. |
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Keywords: | Enchytraeid peat acid deposition ammonium deposition Calluna vulgaris grass |
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