A Buzz in the Meadow (23 page)

I decided to do some experiments. The first step was to check whether the pink hybrids were fully viable and healthy. Some species can interbreed, producing hybrid offspring (lions and tigers, for example), but the hybrids are sterile and so the two species cannot merge together. I crossed red and white campions in the glasshouses at Southampton University, keeping the males and females in separate sections of the glasshouses and pollinating them by hand using a paintbrush. I reared the pink-flowered offspring, which grew vigorously, and the following year I crossed the hybrids with one another and with both parent species. Once again all the offspring were healthy, and I soon ended up with a lovely array of flowers in all shades from white to red. If anything, the hybrids were larger and healthier than their pure-blood parents, which left unanswered the question of how the parent species remain distinct. Although there were more females than males in the hybrid offspring, there still seemed to be plenty of males to go round.

It occurred to me that these hybrids might be less healthy if they were growing in a natural situation, where they would be exposed to competition from other plants and to grazing by herbivores, rather than in the benign environment of the glasshouses. Perhaps the hybrids would be ravaged by slugs, or all their seeds would be consumed by campion moths, and this could explain why the two parent species did not blend together. I decided to set up a long-term field experiment. At the time Southampton University was fortunate to own a substantial country estate, Chilworth Manor, just to the north of the city. The manor had been converted into a rather posh hotel and conference centre – in fact I had been put up there when I was interviewed for the lectureship at Southampton. The grounds included a traditional Victorian walled garden, which was available for members of the biology department to conduct experiments, and extensive woodlands. I planted out replicate patches of both white and red campions, and their hybrid offspring, in woodland and in the open, sunny walled garden. My prediction was that the white campions should thrive in the open, and the red campions in the woodland. If the hybrids failed to thrive as well as the parents in either habitat, because they were poorly adapted to either habitat or because the hybrid populations became dominated by females, this could explain their relative rarity in the wild.

I monitored these campion populations for nine years. In the woodland none did particularly well. Grazing by deer was heavy, and the white campions and the hybrids quickly died out, while only the red campions clung on, although they produced few flowers and fewer offspring. In the walled garden all of the campion patches flourished. Campion moths attacked many of the seed capsules of both white and pink campions, never the red, but there were always plenty left over and seedlings sprouted up everywhere. Pollinators moved between my patches, and soon most of the offspring were pink hybrids. The original parental plants eventually died, and after six or seven years there were few plants left that resembled the parent species. There was a female bias in the hybrid populations, presumably because the selfish cytoplasmic genes had become decoupled from the Y-chromosome restorer genes, but about 30 per cent of the populations were male, which seemed to be enough to pollinate the females. Overall – and contrary to my predictions – the hybrids seemed to be winning. I would have liked to continue this experiment for many decades, to discover the eventual fate of my campion populations, but it was not to be. To my frustration the university sold the walled garden to developers, and my campion patches were swept away in their ninth year, to make way for the shiny glass-and-steel buildings of a science park.

One of the great difficulties in ecological research is conducting long-term experiments. Grant funding rarely exceeds three years, so most experiments are designed to take no longer than this, yet any ecologist will tell you that many ecological processes occur over the timescale of decades or longer, and evolutionary processes usually take much longer still. Of course any large-scale experiment is also likely to need a fair bit of land, and land is cripplingly expensive in most of the UK. My campion experiment was not the greatest experiment ever, and perhaps I had found out all that I was going to, but its loss was annoying and was one of the driving factors behind my purchase of Chez Nauche. With my own piece of land I could set up experiments that could go on for as long as I liked, with no possibility that they would be destroyed by factors beyond my control (being in the middle of nowhere, there is little likelihood of a compulsory-purchase order for the construction of a bypass, housing estate or shiny new science park). So, in a roundabout way, perhaps I owe a small, begrudging debt of thanks to the university administrators who decided to flog off assets to raise money, and perhaps even to the politicians behind the university funding cuts that forced this decision, for without them perhaps my meadow in France would still be a cereal field.

For me, campions and their many associations are a lovely example of the interrelatedness of life. Genes flow within and between species, carried by moths and bees, along with fungal diseases that castrate male plants and turn female plants into false males. Moth caterpillars eat the seeds and are in turn predated by birds, or parasitised by tiny wasps or flies. If they survive to adulthood, the adult moths are hosts for tiny mites that live in their ears, and are food for the bats that hawk above the long grass, which are themselves hosts to fleas, lice, ticks and blood-sucking flies. Every living thing in the meadow – be it beautiful, mundane, gruesome or obscure – is linked to everything else, by just a few degrees of separation. The complexity of these myriad interactions is far beyond our ability to understand, and perhaps it is both arrogant and futile even to try. Maybe we should simply be happy that it is so, and try not to mess it all up too much.

PART III

Unravelling the Tapestry

I hope you realise by now that every creature has a story, and that most of those stories have yet to be told. There is so much that we do not know about almost all of the ten million or so species of organism with which we share the planet. It would be a terrible shame if these creatures were to be lost, be they elephants or earwigs, lions or ladybirds. What is more, these animals and plants, fungi, viruses and bacteria do not live in isolation. Their lives, and ours, are inextricably woven together. We don't know how it all works – and yet we are thoughtlessly picking it apart. Many species have been lost, and more disappear every day. The threads of the tapestry are being picked out, one by one. In this final section I will give you some glimpses of what we have done, and of the huge risks that we run by continuing to harm the environment on which we are utterly dependent.

I don't want to depress you. Nobody likes bad news, but please don't stop reading here. This is the most important bit. Life on Earth is wonderful and unbelievably complicated. It would be madness to continue to destroy it. It is not too late to ensure that our grandchildren inherit a world that is almost as rich in wonders as our own. The window of opportunity is open for us to act, although it will not remain so for much longer. But first we must understand where we are, and how we got here …

CHAPTER THIRTEEN

The Disappearing Bees

16
May
2013
. Run:
40
mins
10
secs. A cool, misty morning, promising to brighten up. I'm feeling fuzzy-headed today; a pair of garden dormice kept me awake half the night with their angry chatter. As I set off I spotted a little owl perched in the dead elms. I thought I'd heard its distinctive hooting over the last few nights, competing with the racket from the mice. People: one farmer in his tractor in standard French farmer uniform of blue overalls. Dogs:
5
. Butterfly species:
13
, including a Glanville fritillary. The mist also helped me get close to a pair of frolicking hares, endearingly gangly and lolloping creatures.

To the north of my meadow in France the boundary is marked by a green lane, flanked by hedges. The hedge on my side is overgrown and about three metres thick. In spring it is full of blackthorn blossom and nesting birds, and in autumn it drips with fat purple sloes, perfect for sloe gin. I probably ought to cut it back, but I rather like it the way it is, and in any case I haven't saved up enough for a hedge-flail for my tractor. The hedge on the other side of the track is barely sixty centimetres tall and less in width. The farmer who owns the field beyond keeps it so heavily trimmed that it has little value for wildlife, and the stunted shrubs struggle to survive at all. He is an arable farmer, and sows his fields each year with wheat, maize or sunflowers. The many fields of sunflowers are one of the great pleasures of visiting the Charente in July. The serried rows of huge, nodding, sun-warmed flower heads, fringed with golden-yellow petals, are a sight to fill the heart with joy. Somehow fields of oilseed rape just can't cut it in comparison. Sunflowers are much loved by bees – both bumblebees and honeybees – and by other insects, and they flock to the cornucopia of nectar. Which would be great: gaudy flowers, happy bees. Except for one insidious, invisible factor that is perhaps one of the greatest threats to bees and to other farmland wildlife. But before I explain what that is, let me rewind a little.

Bees have been steadily declining for sixty years or more. Not just bumblebees, but probably most of the other wild solitary bees, too. I often say that these declines are undoubtedly driven by agricultural intensification, but that is a vague and woolly statement. Agricultural intensification has taken a myriad of forms: loss of hedgerows, abandonment of rotations, increased use of synthetic pesticides and fertilisers, mechanisation, drainage of marshes, and many more things besides. Our countryside has changed massively, but over such a long period it is very hard to notice. Just as one barely notices one's own children grow, so we struggle to detect gentle, steady changes. Until one day we look back and say, ‘Hang on a minute, I can remember a time when I was a child when the buddleia bush in my parents' garden was covered in butterflies. Why hasn't mine got any?' But it is hard to be sure that it isn't just seeing life through rose-tinted spectacles. Was the buddleia bush really always covered in butterflies, or is it just that you remember one particular day when they were especially common? After all, wasn't it also always sunny?

For most of our wildlife it is hard to quantify how their populations have changed over the last fifty years. We can count bees, or earwigs, or voles (although each poses different challenges when it comes to devising repeatable, meaningful ways to count them), but we have few or no numbers from the past for comparison, so it is very difficult to say if there are fewer of them now than there were then. What we usually do have are distribution maps from the past (admittedly often patchy in coverage), and these can reveal that species have disappeared from parts of their former range. Among the bumblebees there are some dramatic examples. In the 1950s the great yellow bumblebee used to be found throughout Britain, from Orkney to Cornwall, but now it is confined to Orkney, the Hebrides and the far north coast of mainland Scotland.
1
The short-haired bumblebee was once widespread in the south-east, but is now extinct there. However, most of our species have not shown massive range declines. We can still find common carder bumblebees or early bumblebees almost everywhere in Britain, but whether there are fewer of them than there used to be we cannot say with certainty, although I would guess this is so.

For just a few wildlife groups we do have really good long-term data sets on how their populations in the UK have changed. Keen amateurs have been recording numbers of birds, butterflies and moths for many decades in repeatable ways, providing figures that we can compare directly over time. For example, the butterfly-monitoring scheme was started in the 1970s. Volunteers walk a regular route every fortnight throughout the spring and summer, identifying and counting every butterfly they see. Some routes have now been walked regularly for well over thirty years, and there are currently in excess of 800 routes being walked every two weeks, scattered all over the UK. This provides the best long-term data on any insect group in the world. Birders have been doing similar things for even longer, so for birds and butterflies we can quantify exactly what is happening. Sadly it is mostly bad news, particularly for the birds, butterflies and moths that live on farmland.

We would expect most wild animals and plants to have declined from the 1950s to the 1980s, for we know this was the period of great changes in farming, when little heed was given to the needs of wildlife, and increasing food production seemed to be the sole priority. The policies in place were brought in during the Second World War, when Britain was cut off from external food supplies, and maximising food production was therefore understandably of paramount importance. These policies catalysed a great era of change, during which we lost our hay meadows, chalk grassland, hedges and much else besides.

By the 1980s things were changing. Food surpluses in Europe – grain and butter ‘mountains' and wine ‘lakes' – led to policies to remove land from agricultural production, much of it going into set-aside, with farmers receiving payments for not growing crops. Set-aside land was left fallow, giving a little breathing space for wildlife.
2
There was a dawning realisation that we had been steadily obliterating farmland wildlife, and that our trajectory might not be either sustainable or desirable. It was becoming apparent that farmers need bees to pollinate crops, and ladybirds, lacewings, ground beetles, wasps and hoverflies to eat greenfly and other pests. Chemicals such as DDT, heralded as a wonder-cure against all pest insects when it first came on the market just after the war, had long since been banned, when it turned out that they persisted in the environment for years, accumulated in food chains and were building up in humans. Raptor populations are only now recovering from one of the unexpected side-effects of this chemical; it thinned their egg shells, so that the eggs usually cracked before hatching.