conference season

I rounded off my week of museum-based self-improvement by tacking an extra day on to my holiday, and going to the Essex Beekeepers Annual Conference.  The big draw for me, as soon as his name was announced at the conclusion of last year's conference, was Professor Nigel Dunnett of Sheffield University.  His full job title is Professor of Planting Design and Vegetation Technology, and Director of The Green Roof Centre.  He and his colleague James Hitchmough, Professor of Horticultural Ecology, have been studying alternatives to traditional planting schemes for urban landscapes for years.  I first came across their names while at Writtle, and more recently Nigel Dunnett emerged slightly further into the public consciousness as designer of the planting for the London Olympics site.

Today's talk focused on his development of what he terms Pictorial Meadows, ornamental planting mixtures inspired by wild plant communities and traditional meadows, but which adapt them to create something with more visual impact and a longer flowering season for use in urban settings. As Prof Dunnett observed, echoing a view of Piet Oudolf, if public planting schemes don't appeal to the mass of people, because they are perceived as messy or boring, they won't get public support, however ecologically sound they might be.

Dunnett's starting point with his meadows, back in the early 1990s, was that cash strapped councils couldn't afford to maintain traditional bedding and borders in their parks as they had done, while there was a great deal of urban grass that was regularly mown, at a significant cost in terms of labour and pollution, but not used for anything.  He thought that sowing areas with mixtures of flowering plants chosen from around the world to provide a long flowering season might be a better and cheaper alternative.  The flowers would be attractive to humans and insects alike.  Sheffield's verges and neglected parks could do their bit for nature conservation, and the sight of brightly coloured flowers and butterflies would make people happy.

Since then he has been researching mixtures of plants that will work well together on different types of site, and canvassing public opinion on his meadows.  His hunch was correct.  Most people really like them.  Annual meadows are sown in April or May on a clear site, should bloom until the first frosts, and by February have shrunk to light, dried stems that can be swept away.  They may naturally re-sow themselves giving a second year display, but by year three will be getting rather weedy.  The seed is mixed with sand or sawdust to bulk it out for broadcast sowing, and if the client is feeling rich or ritzy a two inch layer of sand spread over the site before sowing will suppress the weed seed bank and give the sown annuals a head start. They can be in full flower within two months of sowing, and are a good way of covering development sites that are lying temporarily bare for a year or two, as well as beautifying verges, roundabouts and parks.

The original soil on the Olympic planting site was so contaminated that it was not judged safe for humans to touch it, never mind plant it up and invite tens of thousands of visitors.  It was removed and replaced with artificial soil, which was conveniently weed free.  Prof Dunnett was hired on the strength of his track record, but that didn't prevent the organisers from being so nervous at the spectacle of nothing but bare earth four months before the Games were due to start that they insisted on a contingency supply of turf being lined up.  Sadly, the general public will not get to see the Pictorial Meadow in its original form when the Olympic site reopens as a park.  The ecologists on the planning committees have insisted that the long term planting should draw more heavily on native plants, to restore the Lea valley vegetation towards what it might have been two hundred years ago.  Plus, that many exotic flower seeds don't come cheap.  Which is a shame, for those of us who didn't go to the Olympics, as the pictures looked very pretty.

He does perennial meadows as well, but didn't really cover those today.  Pity, as I'd have liked to hear how his views lined up against those of Piet Oudolf and Noel Kingsbury.

The last talk before Prof Dunnett was from Professor Dave Goulson of Sussex University, on the subject of neonicotinoids: The impact of neonicotinoid insecticides on bees and the wider environment.  Prof Goulson's research speciality is bumblebees, not honey bees, and his conclusion is that the impact of neonicotinoids on wild bees is pretty dire.  Neonicotinoids are incredibly toxic to insects, approximately 5,000 times more so than DDT.  A gramme, or roughly the quantity of a sachet of sugar, would be capable of killing 250 tonnes of bees.  Non-lethal doses appear to him to check growth in the size of nests, and reduce the end of season production of new queens that would form the basis of the following year's colonies.  They seem to reduce the ability of bees to navigate in unfamiliar locations, and curb pollen collection.  Domestic bee colonies are not so easy to measure, for a variety of reasons, and the evidence is still inconclusive on that score.

Neonicotinoids are mostly used as seed dressings.  The chemical is absorbed into the plant as it germinates, and every part of the plant is then toxic to insects.  All insects.  A bee foraging on treated flowers will ingest the insecticide with the nectar, more so in the pollen.  Only about two per cent of the chemical used on seed ends up in the plant, however, with the other ninety-eight per cent blowing off as dust during sowing, or leaching into the soil and soil water, where it has a long half life, estimated at 200 to 500 days, depending on the conditions.  Over the course of a six year study the concentration in soil sown each year with treated seed increased through the period.  The study was included in the data supplied to the regulator during the licencing process.  The EU regulator concluded that it had 'no potential for accumulation in soil'.

In Oregon this July lime trees in a car park were sprayed with a neonicotinoid to kill aphids and prevent honeydew from dripping on the parked cars.  By the end of the week thousands of bumblebees were dead, and officials were attempting to net the trees to keep further bees off the flowers.  The trees could remain toxic for years.  Thousands of bumblebees is a lot, since a nest only contains around three hundred.  Neonicotinoids are not nearly so toxic to vertebrates as they are to insects, which is good news for us.  Except that a partridge ingesting just five treated maize seeds in a sown field would receive a lethal dose.

I went to the conference agnostic on the subject of neonicotinoids, and reassured by Defra's stance on the subject.  By the end of Dave Goulson's talk I was deeply worried.  Now Prof Goulson is strongly in the anti camp, and obviously it would have been better to hear both sides of the story, particularly as the professor is a very good speaker, fluent, charismatic, and funny, besides being really rather good looking.  Before making up my mind I ought to hear someone from Defra, or perhaps Owen Patterson, putting the other side of the argument.  Maybe they weren't invited today, or perhaps nobody was available.  In the meantime I shall remain deeply worried.  What makes it even more depressing is that according to Prof Goulson, while it is almost impossible to buy untreated oilseed rape seed nowadays, the graph of UK output since the early 1980s shows no increase at all since neonicotinoids were introduced in the first half of the nineties.  Output has fluctuated from year to year, but the trend has remained resolutely flat.