Insects are quietly but rapidly disappearing. Michael McCarthy explains why their loss is bad news for the planet.
In Obstgärten finden unzählige Tiergruppen ihren Lebensraum: Vögel, Fledermäuse, Schläfer, Igel, Spinnen, Schmetterlinge, Schwebfliegen, Käfer und weitere Insektengruppen. Über 1000 Arten von Insekten, Spinnentieren und Tausendfüssler wurden in Obstgärten festgestellt. Besonders wichtig sind Obstgärten für Vögel: Rund 40 Brutvogelarten leben in der Schweiz im Lebensraum Obstgarten. Dies entspricht einem Fünftel der einheimischen Brutvögel.
We grow flowers in our gardens for our own enjoyment. But colour and perfume are really the plants’ way of advertising themselves to insects. Sweet nectar and protein-rich pollen are bait to encourage insects to visit. In return, pollen is carried from one flower to another on their bodies so the flowers are fertilised. Bees are among the most beneficial insects for a garden. The best way to attract them to your garden is to provide them with some of their favourite plants such as lavender, foxgloves, rosemary, sunflowers and bluebells. Flowers with long narrow petal tubes, such as evening primrose and honeysuckle, are visited by moths and butterflies. Only their long tongues can reach deep down to the hidden nectar. Short-tongued insects include many families of flies and some moths. They can only reach nectar in flowers with short florets. Hoverflies, wasps, ladybirds, lacewings, ground beetles and centipedes are the gardener’s friends and will help control garden pests such as aphids and caterpillars. Insects such as spiders, mites, millipedes, sow bugs, ants, springtails and beetles inhabit the soil food web in the uppermost 2 to 8 inches of soil. They participate in decomposing plant and animal residue, cycling nutrients, creating soil structure and controlling the populations of other soil organisms, including harmful crop pests. Decaying organic matter in soil is the source of energy and nutrients for garden vegetables and ornamental plants. By growing flowers attractive to a range of insects, our gardens can also become important feeding stations for bats, hedgehogs, birds and other wildlife. The most important factor when encouraging wildlife into your garden is not to use insecticides.
2010 veröffentlichte der holländische Toxikologe Henk Tennekes ein international beachtetes Fachbuch mit dem Titel »Disaster in the Making«. Er beschreibt das extreme Artensterben bei Insekten und Vögeln der Agrarlandschaft – in England genauso wie in Holland oder Deutschland. Rebhühner, Kiebitze, Haubenlerchen und Braunkehlchen und selbst die früher so häufige Feldlerche werden immer seltener. Tennekes belegt das Artensterben mit vielen wissenschaftlichen Publikationen, die er in seinem Buch vorstellt. Die Ursache sieht der Toxikologe in einer Gruppe neuer Pestizide, der Neonikotinoide. Diese fordert er sofort zu verbieten. Noch vor Weihnachten 2011 kam die limitierte deutsche Ausgabe mit dem Titel »Das Ende der Artenvielfalt – Neuartige Pestizide töten Insekten und Vögel« auf den Markt.
The species richness of flower-visiting insects has declined in past decades, raising concerns that the ecosystem service they provide by pollinating crops and wild plants is threatened. The relative commonness of different species with shared ecological traits can play a pervasive role in determining ecosystem functioning, but information on changes in abundances of pollinators over time is lacking. We gathered data on relative abundances of bumble-bee species in Swedish red clover fields during three periods in the last 70 years (1940s, 1960s and present), and on clover seed yields since 1921.
Bumble bees (Bombus) are vitally important pollinators of wild plants and agricultural crops worldwide. Fragmentary observations, however, have suggested population declines in several North American species. Despite rising concern over these observations in the United States, highlighted in a recent National Academy of Sciences report, a national assessment of the geographic scope and possible causal factors of bumble bee decline is lacking. Here, we report results of a 3-y interdisciplinary study of changing distributions, population genetic structure, and levels of pathogen infection in bumble bee populations across the United States.
We assessed 30 triticale fields (15 organic vs. 15 conventional) and recorded vascular plants, pollinators, aphids and their predators. Organic fields had five times higher plant species richness and about twenty times higher pollinator species richness compared to conventional fields. Abundance of pollinators was even more than one-hundred times higher on organic fields. In contrast, the abundance of cereal aphids was five times lower in organic fields, while predator abundances were three times higher and predator-prey ratios twenty times higher in organic fields, indicating a significantly higher potential for biological pest control in organic fields.
Pollinators are an essential part of a garden; so essential in fact, that 90 percent of the 250,000 flowering species now in existence rely on them according to the University of Georgia. Bees and butterflies make up the largest group of pollinators; however, the interior design of certain types of flowers makes it impossible for bees or butterflies to pollinate. These plants must rely on other types of insects to seek out the nectar they produce and pollinate them in the process.
Britain’s 30 million hedgehogs have been reduced to 1.3 million in the last 50 years. Three quarters of butterfly species are in decline. Britain has lost three of its 24 species of bumblebee in last 70 years. Moths numbers have dropped by a third since 1968. In the last 100 years, around 60 species of moth have become extinct. There are those who say all this angst about biodiversity is nonsense. But such free-marketers are wrong. Scottish Natural Heritage’s list of over 1,000 threatened species is not dominated by nice furry mammals or dramatic birds of prey, but by obscure lichens, algae, fungi, flowering plants, beetles, and more than 300 other insects on which the chaps at the top of the Mikado’s list depend, including us. “Therefore never send to know for whom the bell tolls; it tolls for thee.”
The pesticides industry stands accused of failure to investigate the hazards of systemic neonicotinoids fully and of failure to establish standard tests and protocols. Bee Culture Magazine has published a letter from Dr. Rosemary Mason, an independent researcher in the UK and bumblebee expert (who has created a private bumblebee reserve in Wales), that has raised serious questions about US EPA credibility in allowing systemic pesticides to be registered when these products clearly received insufficient testing (attached). She was critical of the report jointly authored by USEPA and Bayer CropScience that emerged from the February 2011 SETAC Pellston conference on systemic pesticides. The report was edited by David Fischer, Environmental Safety, Bayer CropScience LP, Research Triangle Park, North Carolina, USA and Thomas Moriarty, Office of Pesticide Programs, US Environmental Protection Agency, Washington DC, USA. Summary of the SETAC Pellston Workshop on Pesticide Risk Assessment for Pollinators, 15–21 January 2011, Pensacola, Florida, USA. Document attached. John Hoar of the Fareham BKA inferred that although the SETAC ‘Pesticide Risk Assessment for Pollinators’ workshop stated that harmonised toxicity tests (acute and chronic) are still to be developed for systemic insecticides, The Advisory Committee on Pesticides (ACP) Annual Open Meeting in November 2011 had said it might be another five years before a standardised test for chronic bee toxicity guideline will be developed. He said that until there is a comprehensive pesticide risk-assessment for bees, we are entitled to know the location of crops sown from seed treated with systemic pesticides (Hoar's article in the October 2012 edition of BBKA News is attached). Attached also is an article on the influence of Bayer Cropscience on Dutch policy makers (which appeared in the magazine "Vrij Nederland" on April 4, 2012).