Is there a risk of localised die-off when plants bud too early?

Question

I've been taking a few walks in the countryside in Scotland and England this winter (end of December 2014). Some parts of England haven't had any frosts yet, which is very unusual, and it's been generally quite warm since summer ended.

My friends and I agree that there's quite a lot of stuff putting out shoots and buds, as if it's April already. I can imagine that this means a lot of small fragile plants could get killed if a hard frost comes in the next few weeks. If so, it seems natural to expect that next summer will be marked by an absence of these plants, and, being dead, they won't put out seeds or otherwise reproduce for next year. In other words, we're expecting some species to experience localised die-off.

Is this plausible or are we just imagining it? If it's actually happening, is it something to actually be worried about? i.e. will a large portion of the seeds/shoots/buds/whatever refrain from growing even if some are being tricked by the mild winter, or will they be cold-resistant if they're coming up now, or is some other mechanism going to make it all okay? Alternatively, is this winter likely to trigger a large ecological change?

I realise this question doesn't single-out any particular species for attention, and perhaps it's too much of an open question for StackExchange's taste, but I'd very much appreciate some insight into how fragile or robust is the distribution of British plant life when the weather is abnormal, as it is right now.

Answer 1

If you're talking about shoots or buds coming out of individual seeds, then those plants are probably doomed. Most seeds are "designed" as one-shot delivery packages. In this case, they'll bud, be killed off by a frost at some point during the winter, and then be spent.

For a perennial plant like a tree that buds year after year, the impact of an early blooming will depend on the species. As per a Q&A from Cornell (Will Warm Winter Wither Plants?, 2007), most plants growing in a temperate climate (like that of Britain) will have experienced warm winters before and will have at least some evolutionary adaptations to help them deal with occasional aberrant weather. For example, even if you do see some fresh buds on a tree this time of year it is likely that the majority of its bud primordia (the parts of the plant that will someday become buds) have not developed. Although you won't see regrowth in the spring of most of the buds that opened early, you will see normal development of the buds that stayed dormant during the winter.

As for the question of wider ecological change, one anomalous year isn't going to make a difference because, as you say, a large portion of the seeds/shoots/buds/whatever refrain from growing even if some are being tricked by the mild winter. However, if a string of mild winters cause significant die-off year after year you would start to see changes in the ecosystem. It works the same way for many with loosing their hair...