Natur-al-Andalus: On the Nueva Umbria sand spit

Monday, February 15, 2010

On the Nueva Umbria sand spit - 13th February, 2010

It's been a very wet day today here. Swallows amazingly came in during a brief lull in the weather. It's a good opportunity to catch up with the rest of the weekend. On Saturday we were in Huelva for a regional meeting of the Quaternary Association (AEQUA). We've belonged to this group for 16 years now and their field meetings (twice a year) are well worth going to as they are held in special places around the southern Iberian Peninsula and they bring together experts who talk about the sites being visited: geologists, ecologists, palaeontologists, archaeologists, geographers and historians. This meeting focused on the very interesting 12-kilometre long Nueva Umbria sand spit.

Lesser black-backed Gull - common wintering along the Huelva coast

The trip to the spit was by boat from a small harbour on the mainland, but not on this one!

Locals were already about collecting shellfish

The short trip to the spit soon took us close to its coast. The entire site is protected and the local gulls acted as wardens!

But they let us land and so the field trip started in earnest

Here Dr Luis Caceres of Huelva University gave us a really interesting history of the spit's formation. Amazingly the spit is still growing eastwards at an average rate of 30 metres per year, having reached over 60 metres some years! With maps we saw that the entire coastline here, all the way down to Donana, was recent in origin. Two thousand years ago Donana didn't exist as we know it - it was a large estuarine lake and the entire coastline has been transformed by the constant action of wind and wave since then. But the transformation has been really rapid since 1862 when the spit had not started to be formed.

The head of the Umbria spit - it won't look the same next year! Notice the cormorants in the distance

Cormorants on the spit head

The area has a rich history, much of it related to the fishing of the Red Tuna, a topic of great interest to me and one that I develop in my book al-Andalus. Here we see the remains of the old Almadraba (the name for the tuna fleet) headquarters, now lying in ruins.

White Storks have taken up residency

Dr Juan Gallego Fernandez of the University of Sevilla, who has made a special study of the spit's flora and vegetation, kindly came down to talk to us about his research especially on the amazing plants that grow on the shifting sands.

...not sure what this species was!

Marram Grass Ammophila arenaria subsp. arundinacea

Sea Spurge Euphorbia paralias

Crosswort Crucianella maritima

Cotton Grass Otanthus maritimus

Sea Holly Eryngium maritimum

Large areas of the spit have been stabilised by White Broom Retama monosperma. Though native to the area it seems to have been planted on the spit in the 1920s and its rate of growth has been too rapid had it not had help. Rabbits spread the seeds, thus creating stabilised dune in which they can burrow. They don't do it consciously of course but the mutual benefits afforded to rabbit and broom have created this habitat, now occupied by Magpies that seem to assist the gulls in wardening tasks! This place looks ideal as a stop over for trans-saharan migrants in autumn. We shall return to see if it is so!