that we recorded one nectaring at the buddleia outside the Obs on June 30th, it having
been preceded by a Humming-bird Hawk Moth (Macroglosum Stellatarum) a few days
earlier. A crop that is far more in evidence today than fifty years ago is Lucerne (Medicago
saliva), which is cropped for fodder around three times each summer. The final cut is
usually delayed by the cereal harvest, allowing it to flower, and at such times can attract
huge numbers of butterflies. The summer of 2002 was a poor one for most species but
on August 14* there were at least 50 Clouded Yellows (Colias croceus) in the field
behind the Obs - a wonderful sight. The appearance of this species in good numbers
even during poor insect migration years, such as this one, cannot be explained by Lucerne
alone, though, and may be connected with the balmier weather we enjoy nowadays
compared with the 1970s and 80s, when they were seldom seen.
The seaward side of the wall has also seen massive changes during the past few decades,
due largely to erosion of the saltings by a combination of a slowly sinking land and
rising tides. This has been particularly severe where the major creeks exit into the sea.
There is also the problem of roll-back. This occurs where large quantities of sand and
shell are picked up by winter storms and deposited on the marsh beyond the existing
beaches. For instance, the shell-beach in front of the Obs was over a hundred yards from
an old fence line in the 1970s; nowadays it laps against the posts! This has wreaked
havoc on a once impressive flora but a few species, once thought lost, have reappeared;
Sea Kale (Crambe maritima) occasionally popping its head unexpectedly through the
shell after being buried for several years. At the present time a few of the beaches between
St Peter's and Bradwell Waterside are making a last stand at the foot of the seawall
where, protected by an embankment of shingle & shell, they have stabilised sufficiently
to support a fairly rich flora. Typical species found here are Frosted (Atriplex laciniata),
Grass-leaved (A.littoralis) & Babbington's Oraches (A.glabriuscula); Sea Sandwort
(Honckenya peploides), Sea Rocket (Cakile maritima), Sea Mayweed (Tripleurospermum
maritimum), Sticky Groundsel (Senecio viscosus), Yellow-horned Poppy (Glaucium
flavum), Marram (Ammophila arenaria) and Sand Couch (Elytrigia juncea). In the past
two years a couple of them have been colonised by Sea Holly (Eryngium maritimum),
the first time this attractive species has been recorded from the area as it is not mentioned
in either Gibson (1862) or Jermyn (1974). On a few beaches the sand is sufficiently
compacted to provided a substrate for bryophytes. One such is close to the Power Station,
a building which was opened in 1958 and closed down this year, but which will continue
to dominate the landscape for many decades to come. The moss flora is composed
principally of Brachythecium albicans, Tortula ruralis and the much rarer T.ruraliformis
but a fairly wide range of other drought resistant species are also present including
Barbula convoluta & recurvirostra, Bryum caespiticium, Funaria hygrometrica and
Homalothecium lutescens. I had been hoping that this carpet of mosses would, in their
turn, support a small fungi flora but had to wait until November - and the deluge which
ended one of the driest autumns on record - for the chance to find out. During a visit on
19* I was amply rewarded. By far the commonest species was the lethal Clitocybe
rivulosa, with its inviting sugar-icing caps, but surprisingly, Entoloma sericeum was
16
Essex Field Club Newsletter No. 40, January 2003