Implications of this abnormally early cold snap

[David M]

I've been thinking about how this unseasonably cold snap will affect butterfly numbers next year and wondered if anyone may be able to provide pointers for 2011.

In both 2009 and 2010 we have had prolonged cold spells in both January and February. This doesn't seem to have been too disadvantageous to butterfly populations, given that cold conditions are as (if not more) harmful to butterfly predators than they are to butterflies themselves.

Still, it's unusual (unique in my lifetime) for this country to experience such Arctic conditions before winter has officially started.

I read in my newspaper today that the current weather could actually lead to an earlier spring next year, but even if it doesn't, can anyone suggest what an early and very abnormal severely cold snap might do for hibernating stages of butterflies?

My own 'hunch' is that it could be a blessing in that predators are killed off several weeks before they usually are by regular sub-zero temperatures. We already know that butterflies (at all stages of development) are equipped to survive harsh climatic conditions and that those species present in the UK are generally resident because they have greater tolerances of extremes than those species found at more southerly latitudes.

That said, there are always winners and losers. Could it be that adult hibernators (Comma, Small Tortoiseshell, Peacock, etc) may be hit hard whereas larval hibernators actually benefit?

[Lee Hurrell]

I don't think we will see too much of a difference David. We did have a very cold snap before Christmas last year (I know, my boiler packed up!) although not quite this early.

There was discussion and concern then too, but as was proved in the spring, everything worked as normal, albeit a little later than we were used to.

I think any species evolved to hibernate in any stage of its lifecycle will be prepared for cold extremes like this and as you say, it will harm the predators and parasites more than the hibenators. It will also stop moisture and mould taking some too.

Just my opinion mind.

Minus 18 in Wales over the weekend though, that's gotta hurt...

Cheers

Lee

[jenks]

[quote] Minus 18 in Wales over the weekend though, that's gotta hurt...

Didn`t hurt half as much as being beaten by the All Blacks. But I should be used to that by now. Minus 6 in Cardiff--in November !

[Dave McCormick]

Although I don't know much, but someone I know noticed that in late August/early September there was lots of berries on bramble starting to appear, lots of berries on hawthorn etc... and he told me that that could be a sign of a cold winter. The Plants knowing that it would get colder sooner so they put out lots of berries and seeds so that at least one of the seeds would survive a very cold period and sprout another new plant in spring. Didn't believe him at the time, but seeing how things are now, I am inclined to agree this may have been the case, the wild plants/shrubs/trees telling us its going to get cold. I did notice way more acorns around oaks this year than usual too.

I did notice thought that some species of moth held out longer here than usual (I recorded two species of moth well over a month later than their last known flight period in NI, one a barred red, got two in late September, over a month later than the last NI records of the same time in August. Also had a Single-Dotted Wave at the end of September too, another a month later than normal here. Could have been a sign?

I did see a few Small Tortoiseshell going into hibernation in September, I thought that was early, wasn't sure why that was, I checked them often and as soon as the cold snap hit, they woke up and started flying around (didn't move anytime from going into hibernation until then). Have to check them again to see if they are still there (in a disused stable that is partly exposed to elements like wind and cold). Only thought they would stir if it felt warmer? Wonder why then went into hibernation earlier than normal.

My own 'hunch' is that it could be a blessing in that predators are killed off several weeks before they usually are by regular sub-zero temperatures. We already know that butterflies (at all stages of development) are equipped to survive harsh climatic conditions and that those species present in the UK are generally resident because they have greater tolerances of extremes than those species found at more southerly latitudes.

Unless mice/rats get hungry and can't find food in winter and see some butterflies hibernating...

Although I think last harsh winter had an impact on Light Brown Apple Moth numbers. last summer they were very abundant here with over 100 I saw in one day in the orchard here (which is never sprayed just left as is) and this year, one in my trap in early October and saw 6 early on this year when I disturbed them from grass at a coastal path at dusk and that was it. Across the UK people noticed much lower numbers this year.

[Jack Harrison]

A long cold winter - and of course no evidence that will happen - could be ideal for butterflies. Ask Guy Padfield.

Jack

[Padfield]

The butterflies in the Alps are used to it, of course, and adapted to it. But as I skied up to the mountain village of Taveyanne on Saturday, in bitter temperatures and through thick snow that will remain there until May, I did think of them, hibernating in various stages in the soil and rock crevices and plants buried under all that white. It doesn't hurt them at all - in June the region around Taveyanne will be humming with more species than fly in the UK.

Guy

[David M]

Minus 18 in Wales over the weekend though, that's gotta hurt...

It sure did. I was in Abergavenny (not that far from the -18C recorded in Powys) and even at 10.30 in the morning the temperature was still -8C.

[Lee Hurrell]

Although I don't know much, but someone I know noticed that in late August/early September there was lots of berries on bramble starting to appear, lots of berries on hawthorn etc... and he told me that that could be a sign of a cold winter. The Plants knowing that it would get colder sooner so they put out lots of berries and seeds so that at least one of the seeds would survive a very cold period and sprout another new plant in spring. Didn't believe him at the time, but seeing how things are now, I am inclined to agree this may have been the case, the wild plants/shrubs/trees telling us its going to get cold. I did notice way more acorns around oaks this year than usual too.

Hi Dave,

They covered this on Autumnwatch this year and I think it was a result of last winter if I remember correctly. I may be wrong, if anyone else remembers?

Cheers

Lee

[EricY]

I still rely on the old countryside saying i learned as a child "If ice in november will stand a duck, rest of winter will be slush & muck" Eric

[Piers]

A greater disadvantage to our native species would certainly be mild damp winter and/or a prolonged cool and damp spring.

Felix.

[David M]

A greater disadvantage to our native species would certainly be mild damp winter and/or a prolonged cool and damp spring.

Felix.

I agree. I often wonder whether our unique European climate is contributory to our lack of species, i.e. mild, wet winters and cool, wet summers.

Perhaps something distinctly out of the ordinary will actually help.