Sunday, 6 May 2012

Rain Stops Play

The weather forecast for last Thursday indicated it would be sunny and warm, so I planned to do my (belated) first butterfly survey for the year. Unfortunately, at lunch time on the day the weather bureau changed their minds. More storms were coming through. I decided to risk it. Storms here can be very localised, and with luck would miss me.

The storm heads towards me near Chaumussay.
Well, as it turned out it was the luck that missed me, not the storms. I managed to get one of my 2km squares surveyed, around Chaumussay, but I arrived at my Parc de Boussay square to be greeted by a tremendous roll of thunder and it rained enough to make surveying pointless. Even if it hadn't rained on the day, the Parc de Boussay transects were all so waterlogged from the previous days' rain I would have had to squelch my way along the routes.

A spring form Map butterfly.
My best transects turned out to be slopes to the north of Chaumussay - as always, this is a very rich site - and one over the back of the valley, on a beef and dairy farm tucked away in the valley of a small stream feeding into the Claise. Here I photographed the lovely spring form Map you see above, and discovered a previously unknown (to me, at least) colony of Burnt Orchids.

Burnt Orchid.
Maps are an unusual butterfly in that the spring generation is a quite different coloration to the summer generation. You would think they were different species, looking at their uppers, but on the underside they remain identical. To see the summer form, see this photo I posted some time ago.

Storm water erosion from a few days earlier above one of my transects.
Burnt Orchids are small and often seem to like to grow in dampish places amongst quite long lush grass, where the soil is cool and slightly acid, such as the edge of the cattle pasture I survey along. Curiously they can also occasionally be found on dry limestone sites like l'Eperon de Murat at Ferrière-Larçon. The species must be divided genetically into a couple of ecotypes (similar to subspecies) which have developed adaptations for different types of habitat. They are not particularly common in the Touraine and Berry, although there is a concentration of records for them from the Claise Valley, and nearly 50 sites in the Brenne.

They are the very first French wild orchid species I ever saw, down in the Charente, where they are common on roadsides. You don't get a good sense of the scale in photos, but the flowers are tiny, only a few millimetres across. I think they look like little clowns in their buttoned down the front romper suits.

The storm from our place by the time I got home.
Even though I only got half my survey done I was pleased to be out there, and the various orchids are always a bonus at this time of year (Monkeys, Ladys, Early Spiders and Early Purples were all out in addition to the Burnt-tips). I'm really disappointed to see that my friend Elizabeth and I are the only Anglo looking names on the list of STERF surveyors. I cannot understand why more British people don't get involved. After all, many of them have plenty of leisure time and/or have an interest in nature. Contributing to a well run citizen science project such as this is easy and a terrific way of following the seasons in your area. The project always needs more surveyors, especially in the mountains and away from the Ile de France/Paris region. The more people collecting data the better our picture of what is happening to butterfly populations, and by extension, as butterflies are good indicators of the general state of the natural environment, what is happening on a broader scale. An individual only needs to contribute a couple of hours a month of their time, but it all adds up. If you think you might like to do it, but feel you are not expert enough or have some other concern, please feel free to contact me to discuss how you might help. I can be emailed via my profile link on the right.

Susan

9 comments:

chm said...

Hi Susan,
That’s really the kind of things I’d like to do if I were younger and retired. Nature is always a wonder and most people are not aware of what’s going on in their midst.

What you say about adaptation of a plant to its environment is very interesting. Could we ever know how long it takes an orchid to adapt to a new habitat from dampish, cool and slightly acid soil to dry limestone or vice versa?

Pollygarter said...

"I think they look like little clowns in their buttoned down the front romper suits."

I never thought of them like that before... but always will now!

The Sandons have Burnts in their steeply sloping lawn... but overall the grass is neither lush, nor the soil damp. But they are growing in some greener spots.

Given the fact that the tuffeau varies in hardness quite considerably, from near-chalk to almost-marble, could the ones on the Murat site and these [and the ones on the slope outside the 'other' La Forge] be growing in what, in Mountain and Moorland terms, would be called a "flush"?
And, therefore, getting a better supply of water than the surrounding vegetation would seem to indicater... justathought.

I've been getting superb pictures of these dark skies... but haven't had any chance of putting them up... had the computers off and the net disconnected 'cos of the storms. I'll let you know when they are up on flickr.

Tim [on the easiest machine to reconnect!]

GaynorB said...

I would love to be involved when the time comes that we can spend more timein France...

Colin and Elizabeth said...

Susan, I'm disappointed and frustrated to say that I've yet to do a survey for 2012! This time last year I was approaching my third... Can't do anything about the weather though. Just hope it improves soon.

ladyjustine said...

It's the burnt orchid that's been driving me crazy wanting to know what it was! I'm so glad you've cleared up that mystery. There are thousands near me.

Susan said...

chm: now with gene level studies it would be possible to estimate the time it takes.

Tim: ecotypes are currently flavour of the taxonomists month it seems to me and maybe it's a bit lazy to just explain away these differences in one simple term. Burnt colonies are prone to mysteriously going dormant and then dying and no one has figured out what they are responding to when it happens - maybe their flush dries up.

Gaynor: even if you can only survey once every 6 weeks it is worth doing.

Elizabeth: I don't want to complain too much because we really really need the rain still, but choosing the moment is difficult. At least it is now a respectable temperature most days!

Susan said...

LJ: yes they are very common down your way. St Junien - Confolens area is my old stamping ground, and that's where I first saw them.

Tim said...

When it comes to "flushes" on a mountain or moorland landscape, it is usually at the juncture of two distinct rock types, but what you say about the Burnt Orchid colonies would suggest that a much more tenuous link to a good supply of water is a tenuous link to life.

The 'flushes' I was thinking about would not be as alkaline as the surrounding rock would suggest, as water, following the cracks, would pick up less carbonate than water percolating through the body of the softer rock... the dormancy could therefore be explained by an initial increase in alkalinity as the acid level changed 'for the worse' as the water supply no longer came rapidly through the wider cracks??

Tim said...

The "dark skies shots are up on flickr now.

And I don't call three consecutive days of 11 to 12 centigrade maximum 'respectable temperature' either!