The Algae of Mid-Pembrokeshire Rivers, with special reference to the Western Cleddau River

Redd, Elizabeth Carmen Kinsey (1983). The Algae of Mid-Pembrokeshire Rivers, with special reference to the Western Cleddau River. BPhil thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0001011e

Abstract

The aim of the investigation was to make a preliminary study of the algae found in the Western Cleddau and its main tributaries. The area contains two ponds of different types which were studied as examples of a different aquatic environment. Simple water analysis was carried out on samples from as many sites as possible. Water levels were recorded wherever Welsh Water Authority gauge boards were in position. Two small streams on the seaward side of the Roch/Hayscastle area were studied briefly to give a possible pair of contrasting sites.

Diatom counts were made as often as possible at the main sites and dated lists of algal genera were made for every site visited. These were used to construct a Jaccard matrix. From this a two-dimensional ordination of all the algae found on the thirty-one sites was made.

The main river could be a stable system for most of its length. Only two sites were found to be outside the main groups. One ( Cutty Bridge ), appeared to be prone to intermittent pollution, the other ( Ford Anghof ) showed no signs of pollution but was situated in a woodland with a very thick close canopy for several kilometres.

Algal distribution maps were prepared for genera which were found rarely or had interesting distribution patterns. The two ponds in the area provided some different and interesting algal genera.

St. Catherine's Bridge and Cutty Bridge were visited as faras possible on a daily basis and detailed records of water levels and water clarity were made.