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From June 6, 2006                                                                                                        

Pesticide Use Has Global Implications for People and Wildlife
(Beyond Pesticides, June 6, 2006) The extent to which persistent organic pollutants (POPs), including many pesticides, can have far reaching environmental impacts on wildlife and people from different continents is becoming more and more evident, according to a United Nations agency and scientists engaged in a European bird study.

According to the Gambia Daily Observer, the United Nations’ Food and Agriculture Organization (FAO) is involved with the battle in that country against swarming locusts, which can have a devastating effect on human crops. The FAO recognizes that “chemical pesticides may have adverse effect[s] on human health and the environment,” but also recognizes that “desert locust upsurges can cause significant and widespread crop losses…food security and export earnings may also be seriously threatened in affected areas.” The risk of a locust plague therefore needs to be continuously balanced against the risks of using pesticides.

FAO strives to minimize the use of pesticides against the desert locust as much as possible by encouraging intervention in the early stages of the development of a locust outbreak through its emergency prevention system, or EMPRES. The system reduces the amount of pesticides to be used when locusts are only present in relatively small areas. FAO has initiated applied research into control methods that are less hazardous to the environment, such as biological control and barrier treatments. The organization has also assisted governments affected by the desert locust to set up pesticide management and quality control systems for control operations.

Such efforts to reduce the amount of pesticides used are important for three reasons. First, although the Gambia is a signatory to the Stockholm Convention on Persistent Organic Pollutants, which aims to reduce and ultimately ban the production and use of harmful pesticides internationally, other nations on the African continent are not signatories, or have been granted exemptions from provisions disallowing the use of toxic chemicals such as DDT for pest control. Second, because of the highly volatile nature of POPs like DDT at tropical temperatures, these chemicals are capable of traveling immense distances and do not lose their potency to do harm as they move. Third, POPs bioaccumulate in plants and animals as they move up the food chain, making predatory animals and humans likely to acquire the highest concentrations of these dangerous chemicals.

European scientists engaged in a bird study to be published in the journal Biological Conservation worry that this bioaccumulation may be playing a role in the declining numbers of migratory birds arriving in Europe from Africa during the nesting season, and fear that their dwindling numbers may be a warning of widespread environmental damage. From 1970 to the present, researchers have found that 54 per cent of the 121 long-distance migrants studied have declined or become extinct in many parts of Europe. The study also compared migrants and resident birds with similar characteristics, and in almost every case, the migrant fared worse. Some experts feel that the huge amounts of pesticides now used to kill locusts and protect crops in Africa may be playing a role in the destruction of these migratory bird populations.

Meanwhile, at home in the U.S., insecticides are playing a role in the destruction of wildlife and endangered species in other ways. According to the Thousand Oaks Acorn, last year, the National Park Service found two mountain lions ill from rodenticide poison in the Simi Hills of California. This according to Bonnie Clarfield, National Park Service ranger. More recently, Vallerie Coleman of the Monte Nido community in nearby Malibu Canyon found a bobcat in her yard. The sick cat was also a victim of rodenticide poison.

"When predators ingest toxic prey, they and their offspring are affected," Ms. Coleman said. According to experts, the result is a dangerous, biologically imbalanced environment. Reports show that rodents are becoming resistant to some of the common anticoagulant rodenticides, so people are using higher levels of poison to kill the pests. This trend is likely to become even more dangerous to wildlife, pets and people.
Experts suggest some safe alternatives to pesticides.

The best defense is prevention, sources say. Rats can enter structures through holes the size of a quarter. Mice can enter structures through holes the size of a dime. It is essential to seal holes and entry areas around the house, under the house, in the garage and in hay sheds. It is also important to clean up any areas that rodents can use for food or bedding: they like warm cozy places and are attracted to fallen birdseed, fruit and other food sources.

Experts also recommend the use of physical controls such as Have-A-Heart box traps and snap traps. Have-a-Heart traps are a good option, experts say, because rodents can be released back into the wild, far from populated areas.

Snap traps that are set correctly are very effective and more humane than poisons, experts say. Glue-board traps don't kill mice and rats immediately and may catch non-target species; therefore, snap traps, which are available at local hardware stores, are the best alternative.

To get rid of gophers, experts suggest that you use the "black hole," which is a nontoxic method of control. The "black hole" is also available at hardware stores.

"With a little thoughtfulness and preventive action, we can protect our children, our pets and all the wonderful wildlife that surrounds us," Ms. Coleman said. "Unless we take active steps to protect and preserve our native habitat, our grandchildren and the generations to follow might never have the joy of seeing a bobcat, coyote or beautiful soaring hawk."

For more information on prevention and physical control of rodents, see Beyond Pesticides' rodent management and rodenticide factsheets.