Ptyxis Ecology - Our Botany Blog

Tuesday, 27 January 2009

Blink and you'll miss it!

On one of the wettest days of a very wet summer/autumn last year, I spent an afternoon looking for mosses and liverworts in Druridge Bay - see This was part of the 'Bioblitz' event orgainsised by Northumberland BAP. When the weather is so foul it can be dispiriting doing this kind of thing and it was a real shame for the event, as it meant that (unsurprisingly) very few punters turned up.

However, our dedication (or bonkersness) paid off as we found a very rare moss! Aloina rigida is a nationally scarce species that has never been recorded in Northumberland before. The map below (from the NBN website) gives an over optimistic impression of how common it is, as most of the dots relate to records made prior to 1950. So, not only is it scarce, it has also suffered a big decline in Britain. The next nearest previous records to Northumberland are near Edinburgh and in Durham where it has been seen twice, in 2001 and sometime before 1820!

Distribution of Aloina rigida in Britain & Ireland.

As you can see very well from the picture below, it grows in bare, stony places. The picture is from Michael Luth's excellent CD called 'Bilder von Moosen' (pictures of mosses). Ok, where it grows is not actually 'bare', it is sparsely vegetated. These kind of very open habitats are undervalued but very interesting ecologically. Many specialist species of mosses, liverworts, lichens and invertebrates thrive in these areas. One of the few positive changes to nature conservation policy in recent years has been the recognition of these habitats now as UKBAP habitat, 'open mosaics on previously developed land' as they are now officially called.

If you ignore the stalk (seta) of the spore capsule, these plants grow to no more than about 2mm high, so they are not exactly 'showy'. They are also ephemeral in nature, adapted to be able to colonise new areas quickly and probably not lasting on sites for very long as they become more thickly vegetated. As the nearest recent populations are quite a distance away from Druridge Bay the spores that gave rise to the plants we found must have travelled a very long distance by wind to get there.


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