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| | Ditch flora at the Ouse Washes - The Royal Society for the Protection of Birds (Site not responding. Last check: 2007-10-08) |
 | | Water entering the Ouse Washes has long been known to contain high concentrations of nutrients, particularly phosphorus, and attempts have been made in the Ouse catchment to reduce point source pollution from sewage works. |
 | | Of the 20 submerged and floating taxa that occur at the Ouse Washes, six expanded their distribution significantly between 1978 and 2001 (Spirodela polyrhiza, Potamogeton trichoides, Cladophera, Ceratophyllum demersum, Elodea nutallii and Lemna minor) and four contracted significantly (Enteromorpha, Callitriche spp, Lemna gibba and Ranunculus circinatus). |
 | | Of the 29 emergent plant species occurring at the Ouse Washes, eight increased significantly between 1978 and 2001 (Alisma plantago-aquatica, Alisma lanceolatum, Berula erecta, Butomus umbellatus, Eleocharis palustris, Equisetum fluviatile, Rorripa amphibia and Sparganum erectum) and two decreased significantly (Apium nodiflorum and Oenanthe aquatica). |
| www.rspb.org.uk /science/Processresearch/2001/ditch_flora_at_the_ouse_washes.asp (420 words) |
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