Losses disrupt the ecosystem - Veterinary Practice
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Losses disrupt the ecosystem

Our conservation correspondent is concerned at the decline of insect numbers

ANIMAL species that suffer a dramatic fall in their numbers rendering them susceptible to extinction are frequently in the news. Mountain gorillas, snow leopards, tigers, hyacinth macaws, are just a few of the names that spring to mind.

What links them is that they are all iconic species and as such they generally generate a fair bit of publicity.

Whether those in a position to do something to reverse the decline take any notice is debatable. And for some, such as the various sub-species of tiger that inhabit increasingly densely populated parts of the world, the future may be nothing more rosy than the preservation of isolated populations in essentially “natural zoos” in the form of wildlife reserves.

Behind the scenes, though, there may well be more worrying developments afoot. A congress recently held in York brought together hundreds of the world’s leading entomologists to discuss the plight of insects.

This followed the publication of a paper in the journal Science which concluded that the number of individual insects in the world has fallen by 45% since the 1970s. During the same period the human population has just about doubled.

Coming up with firm figures about how insects are faring is not easy.

Almost a million species are currently recognised but it is thought that as many as seven million more are waiting to be catalogued. Even of those species already known, only a relatively small number have been extensively studied.

Such studies suggest that around a quarter of them are in danger of extinction. This, however, is just the tip of the iceberg since extinction is only one extreme and does not take account of the huge reduction in the number of individuals and hence biomass of those species that are still relatively common.

Insects form the bottom of many food chains and a recent report by the Zoological Society of London stated that “if invertebrates disappeared tomorrow we would soon follow”.

We are all aware of the vital pollination service provided by insects for those food crops that feed most of the world’s people. But they do much more than this.

Dung beetles, for example, are estimated to bene t the US cattle industry to the tune of some $380 million annually. The main threats to insects are, of course, much the same as those to other animals: habitat destruction, pollution, farming practices and, increasingly, climate change. The use of pesticides both at home and more widely in agriculture to control pests can have devastating effects on non-target species.

Habitats that are denuded of insects become denuded of insect-eating birds, reptiles, amphibians and mammals; the whole ecosystem from plants to the higher mammalian predators can be disrupted.

One of the problems is that with notable exceptions, insects can be unloved by humans. Clearly, the likes of butterflies and bumble bees have a large fan club but ants, flies, aphids, locusts and most beetles have few advocates. So if their numbers decline, no one really notices or much less cares.

There is hope, though, that people’s attitudes can change. The charity “Buglife” has managed to get large numbers of people recording sightings of not just butterflies but beetles as well.

Events around the country this year during National Insect Week attracted tens of thousands of visitors.

So there is some interest out there and nurturing it by explaining why insects are important to the world as a whole may help to change views and encourage more people to love bugs.

In our own gardens we can help to reverse the decline by rejecting the use of pesticides and by providing habitats where insects can thrive in the form of log piles and uncut areas of grass.

More insects in our gardens means more animals and birds that prey on them and a much enriched ecosystem. Why on earth would we want anything else?

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