The attached algal flora of the estuary and Firth of Forth, Scotland

Abstract

SynopsisA current intensive mapping scheme for Forth seaweeds shows the normal attenuation gradient of species going upstream in the estuary with the existence of two areas of species depletion in the firth, around Kirkcaldy and Edinburgh. Ordination of species presence data suggests the continuation of estuarine influence into the firth and the possibility of slight differences in composition of the flora between the north and south banks in the mid and inner firth. Impoverishment of the flora around Edinburgh since the 19th century can be ascribed to increased pollution, but possibly also, to a lesser degree, to shore reclamation. Following abatement of sewage pollution, differences in the recovery of the algal flora on different shores may be related to the nature of the pollution-induced animal community. Recent work on the upper estuarine flora of the many small, highly-stratified sub-estuaries of the Forth system has revealed a marked shore zonation pattern of smaller mat-forming species.