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THE ESSEX NATURALIST
The Rapid Survey of an Essex Salt-marsh
By M. Brandon-Bravo, M.Sc.
(Department of Botany and Zoology, Sir John Cass College,
London)
Compared with woodlands and fens, salt-marshes are relatively
simple plant communities, and because they are unstratified, poor
in species and developed on silt soils moulded by the readily
understood patterns of tidal flow, they are frequently visited by-
students from schools and colleges. Often found in desolate and
windy regions, they are of little aesthetic value and the ecological
concepts of colonisation, zonation and succession may be studied
in a habitat that is virtually unaffected by the commercial ex-
ploitation of much of the coast-line.
Although it is easy to take a large party of students on to a
salt-marsh and there point out the more obvious features of
physiological, topographical and edaphic importance, the result
of such labour, particularly for those who are unfamiliar with the
flora, is commonly no more than a short and not very interesting
species list. It is less apparent that the unique features of this
or that particular marsh are lost in a generalized description that
could apply anywhere or nowhere.
On the other hand, inexperienced students can collect accurate
information if they know exactly what is required of them.
Moreover, by using a method that avoids the need for subjective
estimation or tedious measurement, it is possible for the separate
contributions to be integrated and to form a comprehensive and
useful study. Indeed, a number of workers can collect so large
a body of information that isolated errors will be of no
significance.
The area studied is at Wrabness, Essex, on the estuary of the
River Stour. The survey described took place on July 18, 1963,
on the first day of a field course for 27 first-year students from
Sir John Cass College, London, and which was based on the Flat-
ford Mill Field Centre, East Bergholt, Suffolk. The method,
based upon a type of belt transect, has also been applied success-
fully to the study of chalk down and wet heath.
Equipment
(a) The quadrat's. These were of 3/16 inch mild steel rod formed
into a square of 22.37 inches inside measurement (500 square
inches) and divided up by means of 8 gauge steel wire into
25 smaller squares each of 4.47 inches side (20 square inches).
All intersections were welded and the completed assembly
cadmium plated. Cadmium is expensive and a considerable
saving could have been effected by the use of a suitable
marine paint, although this would be less durable. The
quadrats were manufactured by G. W. Hepden and Co.,