The macrophytic vegetation of the River Tees in 1975: observed and predicted changes

• Published in: Freshwater Biology
• Main Authors: HOLMES, N. T. H., WHITTON, B. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1977
• Subjects: Zannichellia palustris
• Online Access: http://dx.doi.org/10.1111/j.1365-2427.1977.tb01656.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2427.1977.tb01656.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2427.1977.tb01656.x

SUMMARY. An account is given of the distribution of macrophytes in the River Tees and its tributaries, north‐east England, together with a critical discussion of the problems involved in recording data in a form which can be used for monitoring long‐term changes of vegetation in rivers. Among the conventions and methods adopted in the present study are an attempt to define the vertical limits of the river sensu strictu as opposed to the bank, the extension of the term macrophyte to include as many visually obvious photosynthetic organisms as possible, the use of a check‐list prepared in advance which contains a wider range of species than are actually expected for the river, and the collection of two different types of standard record for each 0.5 km length of river. The Tees has been the subject of intermittent observations on its vegetation for some 45 years. The most obvious change has taken place since 1965, with a substantial upstream spread of four submerged angiosperm species. Potamogeton crispus, Zannichellia palustris and Myriophyllum spicatum were previously present only in the lower reaches of the Tees, and have spread 25, 9.5 and 4.5 km respectively upstream from their previously known most upstream localities. Ranunculus penicillatus var. calcareus is an apparent invader to the river. It seems probable that these changes have taken place since 1971 as a result of regulation of the Tees by Cow Green Reservoir. Further changes are predicted with the advent of water transfer from the Tyne to Tees around 1980, because at least twenty‐six macrophytes are known to be present in the former river that are either absent or confined to the lowest stretches of the latter.