Holmes, N.T.H. 1993 The distribution of Zostera
and Ruppia in the Fleet, 1991. Report to
English Nature SW region, from Alconbury Environmental
This reports a 1991 repeat survey of that done
in 1985, which followed a more extensive survey
in 1983. All were carried out during August. Ruppia
cirrhosa, Zostera noltii and Z.
angustifolia were all thriving in the Fleet
in very similar proportions to those reported in
previous surveys. The nationally rare alga Lamprothamnium
papulosum had extended its range and abundance.
The west-east and north-south zonation of species
reported from previous surveys was confirmed. Ruppia
cirrhosa was very dominant west of Rodden
Hive Point, but then gives way gradually to Zostera
eastwards down the Fleet. Z. noltii thrives
best along the northern coves, whilst Z. angustifolia
dominates along the shore in the shadow of Chesil
and the main body of the Fleet. The decline of Ruppia
cirrhosa recorded in 1985 has been shown
by the 1991 surveys to be a temporary phenomenon.
Lamprothamnium papulosum was found to be
thriving better in 1991 than it had on previous
surveys. In all surveys, this plant was always found
associated with coarse sandy/gravel substrata where
minimal amounts of organic matter were present.
[NB. Z. angustifolia is thought by other
workers (den Hartog 1989, Brenchley & Probert
1997) to be an ecological/environmental variation
of Zostera marina.]
The various recent potential threats to the seagrasses
of the Fleet (invasion by Japanese seaweed Sargassum
muticum, changes as a result of realignment
of Smallmouth [in 1984?], and storms in 1989) do
not appear to have had any adverse effect on Ruppia,
Zostera and Lamprothamnium papulosum
in the Fleet.
Whilst not directly mentioned in the text, records
for % cover of algae Cladophora agg., Enteromorpha
and Ulva are given for each of the 100+ quadrats
surveyed in 1991.