The Committee received a presentation from Dr.
Phil Smith (formerly a Lecturer in Ecology at Liverpool John Moores
University), who had been undergoing research into the formation of
Southport’s ‘green beach’, located between Weld
Road, Birkdale and Pontin's, Ainsdale.
Mr. Smith provided the following
information:
- The term ‘green beach’ -
‘Groene Strand’ - originated in the Wadden Sea area of
the Netherlands. Similar beaches were found in the Rhine Delta
region.
-
The Birkdale green beach, which had been designated
as an area of Special Scientific Interest because of the richness
and rareness of its wildlife and habitat, was a linear stretch of
recently formed salt-marsh and sand-dune habitat on the foreshore
between Weld Road roundabout, Birkdale in the north, to the
Ainsdale Beach Barrier in the south and its outstanding ecological
interest had been apparent for some years
-
The green beach began to form 24 years as scattered
patches of common salt marsh grass which colonised the open shore.
These patches soon accumulated silt and blown sand to form low
hummocks, the outermost of which have grown more rapidly to form a
line of embryo dunes about 100m west of the original dune
frontage.
-
Another green beach which had formed at Ainsdale in
the early 1930s had also been studied in detail but had been
subsequently washed away by winter storms.
-
The present Birkdale green beach was about 4km long
and up to 2km wide. Growth had taken place westwards by the
development of a series of parallel embryo dune ridges, between
which were areas of salt-marsh and 2 freshwater marshes, the latter
being fed by three surface-water drains. Extensive flooding took
place from autumn to spring but the lagoons (dune slacks) usually
dried up during the summer.
-
Birkdale lies on the southern shore of the Ribble
Estuary which has been silting up since the last ice
age. The long-term survival of the
green beach was attributable to accretion of sand and silt on the
foreshore which, as a result, had become progressively wider over
recent decades. Thus, wave-energy was largely dissipated as the
tide flooded and was insufficient, even in winter storms, to erode
away the hummocks and, later, the embryo dunes.
-
Over the years alder seedlings had grown in parallel
lines of wet woodland – now approximately 12-13 years old.
They had grown in parallel because the seeds had washed up in the
sand lines along the beach.
-
By 2008 the woodland was well established forming an
area of approximately 4½ acres and was now approximately 4km
long and 2 km wide. All of this was new land reclaimed from the sea
– for Sefton!
-
The beach at Formby Point was narrower and steeper
than at Birkdale due to coastal erosion.
-
Rapid coastal change, although giving rise for
concern, was a natural process – normal on a ‘soft
coast’. The term coastline
implied a fixed line but this was not the case, because coastlines
are constantly moving and changing.
-
Most of the Sefton sand dunes were fairly recent in
origin – the dune system at Formby Point having only
developed during the past 300 years.
-
Removal of the green beach would be extremely
difficult and costly – it was tried in the 1970s when
bulldozers were brought in to remove all the vegetation to
‘save the beach’, but the constant influx of seeds and
sediment brought in by the tide led to a rapid re-growth of the
green beach.
-
The green beach was an effective natural barrier to
rising sea levels – sea walls and other coastal barriers were
expensive to erect and maintain.
-
Pioneer habitats had formed on the unique Sefton
coastline, attracting a wide biodiversity of plants and animals.
For example, Birkdale beach provided an ideal habitat for the
natterjack toad and the Sefton coastline boasted the largest colony
in the UK. Another rare amphibian
– the sand lizard was also present.
-
A variety of invertebrates were in evidence, for
example, the tiger beetle, requiring a temperature of 36°c
being found on the northern dunes – one of only two areas in
the UK; dragonflies, which were steadily spreading north (probably
due to climate change); and crickets – which can’t fly
and were believed to have been transported from Anglesey as eggs in
the sea.
-
The area provided the perfect habitat for a number
of birds, including the ringed plover, lapwing, skylark and a wide
variety of wading birds (e.g. snipe, sanderling, etc) and
gulls.
-
The number of new plant species in the area had now
reached the 300 mark and of these 50 were regionally and nationally
rare, for example, the marsh orchid and the Parnassus
grass.
-
The position of Sefton, on the coast, half way
between the south and north of the country, meant that it attracted
coastal plants and creatures from both ends of the
country.
In
response to questions arising from the presentation, the following
points were made:
-
It was unlikely that mud on Southport Beach had
emanated from the gas rig in the Irish Sea.
-
Despite fears surrounding climate change there had
been no recorded increases in tide levels in the last 30
years.
-
The beach at Birkdale had grown in height over the
years, due to the formation of the green beach, as opposed to the
coastline in South East England where the coastline was lowering
and falling into the sea.
-
Studies of the drainage outlets running through the
green beach to the sea (e.g. ‘the Nile’ at the northern
end), had found that they did not pose any risk. The purpose of the
outlets was to take surface water drainage from the streets and
golf course behind the beach. Sewage had not been found in the
channels, although high levels of nitrogen (from the roads) and
phosphorous (fertiliser) were in evidence. However, the bulrushes
which had grown in the channels naturally absorbed these
nutrients.
RESOLVED:
That Dr.
Smith be thanked for his extremely informative, interesting and
reassuring presentation and that all best wishes be extended for
his continued invaluable research into Sefton’s green
beach.