In recent years many species have been spreading north due to the series of mild winters, however the prolonged cold spell late December 2008/early January 2009 - and then the February snow - might set them back.

It would be interesting to compare for example the sightings of kingfishers in 2009 to those in 2008. Kingfishers need access to water to feed and if this is frozen for a prolonged period then they may die.

Kingfishers are not a climate change species in UK, so could be used as a standard to compare the other species against. If their numbers go down then it may be a cold enough winter to cause widespread ecological effects rather than just the normal year-to-year variation in weather.

I would expect several of the insect species that have been rapidly spreading in Britain to have their numbers checked in 2009 and even reduced. Some, though, may be much less affected than the kingfishers if they have an overwintering strategy that can withstand the cold.

Kingfishers have no choice they are here year round, and have to constantly catch food in water to survive. Many invertebrates, however, overwinter as cold resistant eggs or pupae, well insulated in the soil; or perhaps they live in our centrally heated houses. This wintering method is used by creatures such as the spindly spider.

In fact, a number of other species of spiders have taken up residence in our homes in recent years including relatives of the black widow which can have an unpleasant bite.

Photo of relative of black widow in flats in Milton Keynes - might have an unpleasant bite so I left it well alone and did not check.
[image by Mike Dodd © copyright Mike Dodd]

Another effect, of the snow particularly, was to break branches on evergreen trees. I have recently been looking at a 'lost' arboretum where about 60 species of oaks from around the world were planted.

Most of the species are deciduous and they were unaffected by the snow but the evergreen species from warmer Mediterranean climates such as cork oak had many of the main branches smashed down and split. Different evergreen species from northern forests, such as fir trees, have downward pointing branches and needle-like leaves that easily shed snow; the branches also tend to be very flexible and spring back once the load is gone.

One species that I thought might be checked somewhat is the water fern Azolla filiculoides which is an invasive species from North America. It forms a symbiotic relationship with the blue-green alga Anabaena azollae, which fixes atmospheric nitrogen enabling it to rapidly cover water bodies and cause a considerable nuisance.

It generally turns red and grows poorly in winter so I thought the low temperatures may kill it this year but no during fieldwork last week we saw it still smothering one of our boggy woods. However there is now a 2milimetre-long weevil that seems to be eating the plant and acting as a biological control - so its days of smothering ponds may be numbered.

About the author

Doctor Mike Dodd is a research fellow in ecology at the Open University. He is also a keen naturalist: "Nearly all biologists nowadays only study one organism or even just a few molecules, but I have a plea that people should be aware of their whole environment."

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Just finished the fieldwork and breathing a sigh of relief after all the hectic rushing around the country surveying species rich meadows. The fields are mainly in the floodplains of the rivers Thames, Severn, and Derwent. We are looking at various aspects of these species rich communities which used to be a common sight but are now rare, for example what level of water and nutrients do they need/can they withstand. Floodplain meadows are of course subject to occasional flooding indeed they act as flood protection areas for cities such as Oxford, we know these high biodiversity plant communities can withstand a certain amount of winter flooding but what happens when the areas flood in summer when the plants are in full growth like happened in 2007?

The 1300 sample locations have to be surveyed over a short period when all the plants are up and flowering but before they are cut at the end of June. Besides the meadows that we have been recording annually for many years there were several ‘new’ floodplain areas that had not been looked at for 10 years and which proved to be a bit of a challenge. We wanted to record exactly the same 1x1 metre square areas (quadrats) that had been surveyed in the past so that we could see if there had been a change in species composition especially after the severe flooding and lack of hay cut that happened in 2007. The quadrats we record are not marked by anything – the areas are run over by hay cutting equipment and later grazed by animals so we can’t put in above ground sticks and filling each field full of buried metal to mark all 200 squares is not really desirable either. So how do we find them each year and how to rediscover the ones from 10 years ago?

Until this year we had been using theodolite type surveying equipment to accurately measure angles and distances from fixed points, these can position the quadrats to within a few mm if the fixed objects are still present and visible and we can find the ‘origin’ position of the survey. It’s a big ‘if’ when you consider that the origin position is usually a buried dipwell somewhere in the middle of thousands of square metres of waist high grass and that the landscape often changes quite considerably in 10 years. Fences are replaced, trees grow up and obscure reference points, the 10cmx10cm metal lids of the dipwells may be taken away so the metal detector might be of no help in finding them.

We are moving over to a gps based system, its not as accurate as the old system but can usually position the quadrats to within 5cm of where they should be which is fine and is usually significantly quicker as you don’t have to hunt for the fixed points and there is no delicate equipment to carefully set up on a heavy tripod. The gps also gives the locations in latitude/longitude or ordinance survey grid so researchers will be able to go back to those exact positions in future. There is still a bit of a downside to the new system, it may be lighter, quicker and can be one person operated but it does rely on the mobile phone system to get real time differential corrections of the gps signal – this is how it achieves a much better accuracy than a normal hand held gps. Some of our sites have rather poor and intermittent gprs mobile phone coverage which can be very frustrating as the accuracy can go from a couple of cm to a couple of metres and back again as you are walking along so we may even set up our own temporary base stations and use a radio link instead of using the mobile phone for these sites.

What are the results of all this effort by the botanical surveyors and of the chemical analysis of soil and hay, well you will have to wait until at least the autumn for all the data to be typed in and analysed. Just by eye some of the sites looked rather different to normal but this may have been more to do with the lack of a hay cut rather than the water from summer flood itself.

Botanical surveyors setting off to set up quadrats in a flooded meadow beside the Thames in 2008.
[image by Mike Dodd © copyright Mike Dodd]

Normally the meadows are dry at this time of year so it was interesting trying to identify species of grass under 30cm of river water at this site. The red box contains the ‘total station’ theodolite for comparison with gps at setting out quadrat locations.

About the author

Doctor Mike Dodd is a research fellow in ecology at the Open University. He is also a keen naturalist: "Nearly all biologists nowadays only study one organism or even just a few molecules, but I have a plea that people should be aware of their whole environment."

Subscribe to Mike Dodd's posts