Macrophytic vegetation of the River Swale, Yorkshire

Abstract

SUMMARY. An account is given of the distribution down the River Swale in summer 1976 of 132 species of photosynthetic plants which are recognizable macroscopically. Some environmental data are included. The river may be regarded as falling into three zones, both with regard to its physical features and its type of vegetation. The upper zone has rocky substrata, fast flows and a macrophytic vegetation largely of bryophytes; the middle zone has unconsolidated substrata and the macrophytic vegetation is relatively sparse; the lower zone is silted and the macrophytic vegetation consists largely of angiosperms. The flora of the Swale is compared with that of the Tees, since eventually the former is likely to receive water from the latter as part of a major water transfer scheme. Eleven species of ‘river’ angiosperm which are present in the Tees above the projected abstraction point are absent from the Swale above the inflow point.