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Essex Specialities. 3: Annual Sea-purslane
introductions (with the necessary permissions) to suitable Essex sites where it has not been recorded
previously - Old Hall Marshes RSPB reserve and Horsey Island, part of the Hamford Water NNR.
We have deliberately chosen sites which are isolated from the tidal influence, so as not to allow
uncontrolled dispersal.
The future
Our short-term recovery objectives are well on the way to being met. We still have the native
population, albeit slightly displaced from its initial site, and we believe we know what to do to
ensure its continued persistence. We also have insurance populations; at nearby and more distant
sites, in cultivation and in the seedbank. This has been achieved at little cost, without recourse to
high-tech methods: virtually everything has been done in-housc by the English Nature local team.
EN justifiably prides itself in its facilitating role in nature conservation: we are seen as 'the great
enablers'. This, however, is an example of EN actually doing conservation. And doing so in a
pragmatic, almost prescient manner: without our precipitate actions in 1993, Atriplex would almost
certainly be extinct in the wild once again. Not wishing to undermine the value of proper project
planning, if we had gone down the official route of proj ect teams and steering groups, it would have
been too late.
But what of the future? Is this enough? I fear not. All we have done so far really is gardening. Self-
sustaining populations must be the longer-term aim of our Action Plan. For ideas about how we
might achieve that, we should examine the key habitat requirements our researches have indicated
arc important for Atriplex. It appears to be associated with upper salt marshes with a relatively
coarse substrate (eg the interface between sand dunes and salt marshes), in which there are open
germination microsites. The open patches should be maintained by factors other than grazing (analogy
with A. portulacoides would suggest Annual Sea-purslane is highly palatable). The other factors
which can give rise to this open habitat are dynamic coastal processes. In such a situation, the plant
can colonise (being distributed by tides) the open patches as and when they are created by coastal
processes ie Annual Sea-purslane displays metapopulation dynamics.
But the last few centuries of coastal mismanagement have worked against that: upper salt marsh land
claim and the constraint of coastal dynamics with concrete have removed the key habitat for Atriplex.
Fortunately now, the essential role of coastal dynamics in creating a living coastline is being
recognised. Whereas it took a catastrophic event, the Great Storm, to make us realise the importance
of dynamism in woodlands, we are coming to realise the same for coastlines without such a cataclysm.
The only upheaval is in our philosophy and practice of shoreline management. In Essex, at the
forefront of these changes, sea walls are being breached, and more natural sea defences of sand and
gravel are now being introduced, with a view to restoring this essential dynamism. And perhaps
Atriplex in its own modest way can act as a figurehead for that: if we are ever fully to achieve the
recovery objectives of self-sustaining populations, it will be through action and management at the
landscape/process level.
References
GEHU, J.M. & MESLIN, R. (1968) Sur la repartition et l'ecologie d'Halimione pedunculata (L.) Aell.
(Dicotyledoneae, Chenopodiaceae) en France. Bull. Lab. Marit. Dinard 1: 116-36.
GIBSON, C.C. (1991) Annual Sea-purslane at Foulness, Essex. Sanctuary 20: 9.
LEACH, S.J. (1988) Rediscovery of Halimione pedunculata (L.) Aellen in Britain. Watsonia 17: 170-1.
LEACH, S.J. (1999) Atriplex pedunculata L. (Chenopodiaceae). In Wigginton, M.J. (ed.) British Red Data
Books 1, Vascular Plants (3rd Edition). JNCC, Peterborough. p56.
TUTIN, T.G. (1987) Halimione Aellen. In Clapham, A.R., Tutin, T.G. & Moore, D.M. Flora of the British
Isles (3rd Edition). CUP Cambridge. p160.
Essex Naturalist (New Series) 17 (2000)