Been there, dune that

I’d like to take you to the other patch I’ve chosen in which I’m going to try to list all the species of plants I find. Other patch? Yes, the first was in the previous post.  That was in the hills, this is by the sea, and already the comparison is showing me a lot about each habitat.  Here we are at Marseillan-plage:

The dunes of Marseillan-plage, looking west (promenade up on the left)

The dunes towards the port on the east side – promenade now on the right of the image

The town of Marseillan is a very old port on the Étang de Thau, founded in the 6th century BCE by the Greeks; facing the Mediterranean its neighbour Marseillan-plage is – there are no other words for it – a brash new tourist resort, which has invested a great deal of money in the last year to become, well, even brasher. But it has a botanical jewel in its narrow system of dunes.

Jewel? Doesn’t it look just like a patch of dried-out weeds?  Look closer. There are at least two separate main ecosystems here, separated by the promenade between the town and the harbour: the dunes nearest the sea are the least stable, blown by wind and spray, and only a few species can take the conditions: Euphorbia paralias (sea spurge) which I blogged here, Elytrigia juncea (sand couch grass), and Ammophila arenaria (marram grass) are examples.  The Euphorbia can store water in its stems and fleshy leaves.

Elytrigia juncea – sand couch grass – Chiendent des sables

These are the shifting sands – dunes vives in French – pegged down by rows of fencing made of chestnut stakes. These are in place all along the coast, after the damage of a great storm in November 1982 awakened the authorities to the gradual erosion of the coastline by the prevailing east to west currents.

On the town side of the promenade and sheltered by it from the worst of the wind and salt spray, a much more diverse flora has established itself. Although the sand is infiltrated by seawater, there is a layer of fresh water within the sand which lies on top of the salt because it’s less dense, and a plant with roots deep enough to reach this layer can survive. Even so, the plants here in the arrière-dunes show even stronger adaptations to drought than on the sauveplaine. For example, this clump of Paronychia argentea has a low, dense growth habit, and refective silvery bracts round the flowers, creating its own shade underneath.

Paronychia argentea

Many dune plants are covered in a thick downy coat of hairs, which both reflect heat and reduce evaporation, such as this Sea medick (Medicago marina), which is rarely seen away from the coast.

Sea medick – Medicago marina

Others have leaves reduced to slender leaflets, such as Centaurea aspera (rough starthistle) and Anthemis maritimus.

Centaurea aspera – identified by its 3-spined bracts, and Anthemis in the background

One unexpected discovery was the dry stem of this broomrape. These plants are completely parasitic on other plants, and can often be identified by spotting the host plant nearby.  In this case the yellow composite is a clue to its probable identity as Orobanche minor (common broomrape), and this species is often found near the sea. The grass in the picture is Lagurus ovatus : hare’s tail or bunny-tail grass, or Queue-de-lièvre.

Broomrape – Orobanche minor? – and yellow composite which it may be parasitising

I’ve found a couple of other broomrapes recently: they’re stunning flowers and I’ll write a post about them soon.

At the foot of the landward side of the fixed dunes, just before the houses begin, the terrain is more fixed, the water is closer to the surface and perhaps some organic matter can accumulate to enrich the sand – at any rate, some plants here resemble those of further inland, or even those of gardens. For example, a stout Lavatera arborea (tree mallow) would grace any front yard, and the wild leeks (Allium ampeloprasum) are the same as those on the sauveplaine.

Lavatera arborea – tree mallow – at the foot of the arriere-dunes

Allium ampeloprasum- wild leek – just opening in the dunes

The Marseillan patch study is now up to 24 species – I’ll work on a list which I’ll set up on another page on the blog here, and keep updated. The close study of two very different areas is fascinating, and it’s showing me that the dune season is much more compressed, with some flowering seasons over before those in the hills have really started. The grasses in the two places are completely different – I’m trying to get a grip on identifying these.  And over the summer I expect to see the real dune specialists which flower most of the year, such as Anthemis, and others yet to be discovered. But the greatest wonder of the dunes is that very different habitats are found only metres apart, and so in ten minutes you can have a good lesson in ecology. I’ll be suggesting this as an important asset to the municipality – there’s been a lot of redevelopment in the town in the last year and I’d hate for this area, which is like a wild park in the centre of town, to be disturbed to lay drainage pipes or to build ice-cream stands. The rest of Marseillan-plage is concrete, with imported palm trees.

Here’s some music from a region I imagine to be as dry and sandy as the dunes. It’s from the album Jama Ko, by Bassekou Kouyate and Ngoni Ba, recorded in Bamako in Mali in 2012, and something I like very much indeed.  This track, Poye 2, also features the bluesman Taj Mahal, a longtime fan of Kouyate.

Coming up next: Close relations: how do you tell them apart?

 

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