Saturday 23 August 2008

Silent summer?


Images on our TVs are of British farmers shaking their heads beside quagmires that should be fields of harvested cereals. Will the wet August have made the ground too soft for heavy machinery? Will the sodden heads of ripened seeds have been too wet to harvest?

The consequence of the wet August for British farmers is hundreds of thousands of tonnes of unharvested wheat, barley and oats worth millions of pounds. The outcome for the consumer will be even higher prices for bread. Two powerful interest groups bringing the power of the media to bear: farmers and consumers.

And like a line of dominoes falling, the world’s poor will, once again and inevitably, pay the ultimate price when the shortage hits the world market and prices for all cereals rise in an already expensive marketplace. Once again, our humanity will be called into question as we demonstrably will not be able to feed the world.

Powerful interest groups and victims: in common they appropriately share human interest for our hungry media.

But there is another quiet but insistent story arising from this wet summer following the 2007 washout that must be told. It is the story of a disastrous decline in our native insect populations. 2007 was the wettest on record. With populations already depleted by habitat loss and disease, butterflies and bees were mauled by the rain. The hope was that 2008 would be warm and dry. It hasn’t been and from across the country come reports of declines in bee and butterfly populations. The busy-ness of our garden buddleais and borage plants is a great indicator of what is happening in the natural world beyond our gardens. The worrying conclusion is ‘not much’. There are just too few butterflies and of insufficient variety.

Our insects are caught in a three-pronged trap.

The first is habitat loss. In vast areas of my native Nottinghamshire our common frog is now locally extinct. These are the areas of intensive agriculture. The same pressures apply to our insect populations. Rolling acres of arable land leave no room for the plants that our native insects depend on. Our friend the frog is lucky. We can provide breeding places habitats to sustain adult populations in our gardens. The common frog will surely be renamed the garden frog someday soon.

For insects, the garden is not a sustaining option. Butterflies are often highly-specific about the habitat they need for breeding. It is specialists that are facing the hardest time. Native grassland in dappled shade is not easily replicated in our gardens. The stinging nettle is the larval food plant of many of our most common generalist butterflies. Very few gardens I visit have sufficient space to give to a generous bed of nettles.

So, even if we plant our gardens with the stunning butterfly bush buddleia davidii, we are only feeding adults. We are not meeting the needs of their caterpillars – and as every child knows, without caterpillars there are no butterflies.

Our bumble bees are similarly affected. Habitat loss and disease have already put bees under pressure. Gardens full of flowering sage and thyme will undoubtedly help adults later in the season. But if there have been insufficient places for nest building earlier in the season and insufficient flowers to sustain the young from hatch onwards, the bumble bee numbers will continue to decline.

The second and oh so predictable prong is the effect of climate change. Whilst some butterflies have extended their ranges as our climate has warmed, these have tended to be generalists. Specialists have more specific needs and do not have the capacity to change as quickly as our climate is.

So when the third of prongs snaps in – successive wet summers – our native insect populations have insufficient resilience to cope.

We then see further falls in insectivorous bird populations which themselves have been adversely affected by wet weather. Willow warbler populations have been hit in this way. Where we once counted forty house martins basking in the late summer sun, we are now down to twos and threes.

It is a depressing picture.


Individually, gardeners should be doing all they can by including native plants in their gardens as well as introduced plant species that provide nectar.

Collectively, our wildlife depends on the actions of organised groups such as the wildlife trust movement. They act preserving nature reserves that provide the necessary habitats that specialist insects need. They also act as a powerful pressure group, challenging government policy where it runs counter to the needs of wildlife.

For British farmers, several days of dry weather will solve the harvest problems. Our insects’ future is more gloomy. It will take several years of great summers and a change in government policy and land use. The alternative is a silent summer in which the lazy drone of bees is no more than a memory. We should not be prepared to accept this alternative.


4 comments:

Graham_Cliff said...

So - "Our insects’ future is more gloomy." - ? Has anyone reading the comments on this blog given any thought to the concept of the modern 24 hour day causing severe "hidden" circadian disruption? Humans suffer severe "jet lag" effects from circadian disruption traveling over time zones. Bugs cannot turn the lights out so easily at night - nocturnal creatures have completely lost the night. Their nightly habitat has gone because lights are left switched on unnecessarily. Perhaps some of the "mysterious" environmental effects we see can be blamed on circadian disruption? If this is true then there is a very simple solution, isn't there?

Rob said...

Hi Graham,
I wouldn't be surprised if the disruption you describe was affecting insects. I don't think it is the major factor.
In rural Nottinghamshire where insects have lost their habitats there is very little light pollution. Yet their numbers have declined rapidly.
Some 'generalist' butterflies that occupy gardens do face light pollution but their numbers have been less affected.
I thoroughly agree with your implication that we should reduce light pollution. Where I live there is huge scope for that.
Cheers
Rob

Colin Henshaw said...

The effects of light pollution can be seen over a great distance, so just because a location, such as rural Nottinghamshire, is seemingly dark, it does not mean it will not have an effect. I have saw the light polltion dome of Dublin from the Lleyn Peninsula in North Wales, and that was in 1974. One can imagine it is much worse now. Urban light pollution is spreading and getting worse, through the effects of the twenty-four our day. It can be so bad that even diurnal insects, that come out during the day, can be affected.

Colin Henshaw said...

Just because an area, like rural Nottinghamshire, is seemingly dark, it does not mean light pollution will not have an effect. Light can penetrate over vast distances, and if it can be seen by humans, insects will also detect especially if they are flying above treet-top level. I have seen the light pollution dome of Dublin from the Lleyn Peninsula in North Wales, and that was in 1974. I would imagine it will be much worse now. Urban light pollution is ever getting worse, so those areas that are seemingly dark will still be affected. A notable example is the new Great Leighs Race-course facility in Essex, whose floodlighting has been reported to have been attracting moths in large numbers. Furthermore, if the lighting is intense enough, such as this, then it will even affect diurnal insects such as bees that don't normally come out at night. Intense lighting can trick them into thinking it is still daylight.