Archive for September 2nd, 2012

Nature Ramble

Let’s go to the beach.

One doesn’t often think of the sand dunes, or that they may well be under threat.

We sometimes hear about them because of erosion, but this is not a natural threat, it is merely how sand dunes work.

The threats that are mentioned are actually the sand dunes threatening our urban planning, or how we perceive that sand dunes should be. Mother Nature has other ideas.

Sea holly: king of the dunes

Drastic action is needed to save the native plants that thrive on our sand dunes, writes Andy Byfield of Plantlife

Sea holly (Eryngium maritimum). Photograph: Clive Hurford

What has happened to Britain’s sand dunes? My childhood recollections are of wild and windy places; of a fine spindrift of sandy particles streaming from the dune ridges; of marram grass etching precise circles in dry sand with the tips of their leaves; of wavering films of sand flowing across rippled sands. Fast forward 50 years, and today’s sand dunes look more like the Teletubbies’ set once the cameras have stopped rolling. The golden sand has been replaced by a thick thatch of matted grass, burgeoning stands of bracken and scrub, and increasing groves of willow and birch. And as bare sand has become something of a rarity, so many beautiful sand dune species have declined to near-oblivion today. Many of our rarer plants and animals have spent millennia evolving to cope with shifting sands. Like carrot seedlings in an allotment, they need bare ground into which to seed, and simply can’t compete with choking blankets of coarse vegetation.

Just such a plant is the sea holly (Eryngium maritimum), an architectural beauty of the sandy beaches and sand dunes around our shores. The plant’s central cone of flowers is reminiscent of members of the daisy family, such as echinacea or rudbeckia, but sea holly is a relative of the carrot. The ruff of petals is actually a ring of spiny bracts that encircle and protect the flowers like the plates of a Stegosaurus or the frills of a Triceratops. The whole plant is a metallic blue-green, seemingly verdigrised like a bronze garden statue in miniature.

Sea holly is supremely adapted to growing in mobile sand. Its deep-seated rootstock penetrates the substrate to a depth of 1m or more, and the plant takes a masochistic delight in being buried by an avalanche of sand. It positively thrives under such treatment, making it a somewhat difficult plant to please in gardens: if you want to recreate the seaside look in your flowerbeds, stick to easier relatives, such as Eryngium bourgatii, E. giganteum, E. x oliverianum and E. x zabelii. These plants are perfectly happy under normal garden conditions – although they perhaps thrive and look at their best in poorer soils – so you don’t have to buy a bit of the beach at Dungeness (like the late Derek Jarman), or indeed need to live near the coast, to create the look. And there are plenty of easy-to-find and easy-to-grow alternatives for sea holly’s supporting cast of duneland associates. To create the wispy look of marram grass, you might try the intensely blue-leaved Magellan wheatgrass (Elymus magellanicus) from the mountains of South America. Instead of our rare and beautiful native stock, the great sea stock (Matthiola sinuata), plump for the perennial white variety, Matthiola incana, with glistening white flowers over cabbage rosettes of grey-green leaves, and boasting one of the most intoxicating scents of any plant I know. Add in any of the horned poppies (Glaucium species), plus the handsome (and edible) sea kale (Crambe maritima) and you will be well on the way to recreating a small corner of Bognor or Braunton in your home patch.

So what has gone wrong with our sand dunes? Nobody really knows the full story, but a number of factors are thought to be to blame. For starters, we don’t use our sand dunes as heavily as we did in the past: today, dunes are rarely grazed, and we don’t tend to “borrow” sand from small pits, nor use their humps and hollows as military bombing ranges. Additionally, the climate might have changed: summers may be getting wetter (particularly if this year is anything to go by), which encourages vigorous growth of coarser plants; and there is increasing evidence that 21st-century rainfall fertilises the ground by bringing airborne industrial and agricultural pollutants back down to earth. Fortunately, as a species of the exposed foredunes (those next to the beach), sea holly is not faring as badly as some: indeed many other dune plants are faring badly. Take the fen orchid, an elusive green orchid of the South Welsh dunes: known to be locally abundant just a few decades ago, the species has declined from hundreds of thousands of plants at 10 sites to just a few hundred plants at one location today.

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Sea holly on a Polish beach
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