Fonofos poisons raptors and waterfowl several months after granular application.
ABSTRACT From 1994 to 1999 in the Lower Fraser Valley region of southwest Canada, fonofos (Dyfonate G) was recommended for control of introduced wireworm (Agriotes spp.) pests on potato and other root crops. As part of a wildlife-monitoring program, we collected 15 raptors, including 12 bald eagles (Haliaeetus leucocephalus), found dead or debilitated on or near agricultural lands with severely inhibited brain and/or plasma cholinesterase activity and fonofos residues in ingesta. Bird remains, in nine cases waterfowl, were identified in the ingesta samples. Another seven bald eagles had severe cholinesterase inhibition, but without evidence of fonofos residues. During two winters from 1996 to 1998, 420 ha of potato fields, half of which had been treated the previous spring with fonofos and the remainder untreated, were searched weekly for evidence of wildlife mortality. Search efficiency was assessed with placed duck carcasses. Waterfowl outnumbered other species in field-use counts and comprised the greatest proportion of birds found dead. We found 211 wildlife remains, most scavenged; 35 intact carcasses were suitable for postmortem examination and/or toxicology analyses. Cholinesterase activity was assayed in brains of 18 waterfowl, five of which had severely depressed activity (average inhibition 74%; range, 69-78%). The gastrointestinal tract of a mallard found in a field treated with granular product contained 49 microg/g fonofos residues, linking waterfowl mortality with labelled use of the product. These findings demonstrate the risk of both primary and secondary poisoning by anticholinesterase insecticides where wildlife make intensive use of farmed fields.
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ABSTRACT: We studied the poisoning of birds of prey and waterfowl by anti-cholinesterase insecticides from 1989 to the present in the lower Fraser Valley of British Columbia, Canada. It began as an investigation of causes of death of the bald eagle (Haliaeetus leucocephalus) with a focus on the role of lead shot. During the first year, however, a number of eagles and other birds of prey were discovered dead and debilitated from unknown causes. A forensic investigation revealed acute poisoning mainly by the carbamate compound, carbofuran. We subsequently showed that these non-persistent non-bioaccumulative pesticides did indeed persist in local soils from spring application well into the following winter. They could then be ingested by waterfowl as they intensely foraged across the delta farmlands. Seasonal and long-term trends in eagle populations and their winter foraging behaviour contributed to the high rates of poisoning. Carbofuran had been introduced as a replacement for the organochlorine insecticides such as aldrin and heptachlor primarily to control the introduced soil pests known as wireworm, larvae of the Agriotes click beetles. From 1990 to 1999, three organophosphorus (OP) insecticide wireworm control alternatives, fensulfothion, phorate and fonofos, were shown to persist and poison raptors and were each removed in turn from the market. In the early 2000s under the guidance of multi-stakeholder committee, the British Columbia Wireworm Committee, a fourth OP compound, chlorpyrifos, was introduced and has been used for 10 years under an integrated pest management framework to effectively control wireworm, and while it likely has killed some waterfowl, has not been linked to poisoning of birds of prey. Thus, with focused effort and cooperation among agricultural, wildlife and regulatory communities, effective pest control can be achieved without unacceptable poisoning of non-target wildlife.08/2011: pages 213-237;
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ABSTRACT: During the late 20th Century, due to decreases in both contamination and persecution, bald eagle (Haliaeetus leucocephalus) populations increased dramatically. Currently, mechanisms regulating eagle populations are not well understood. To examine potential regulating processes in the Pacific Northwest, where eagles are no longer primarily regulated by contaminants or direct persecution, we examined bald eagle reproductive success, breeding populations, winter populations, mortality, and salmon stream use. Wintering and breeding eagle populations in south-coastal British Columbia (BC) quadrupled between the early 1980s and the late 1990s, and have since stabilized. Density-dependent declines in reproduction occurred during 1986–2009, but not through changes in site quality. Mid-winter survival was crucial as most mortality occurred then, and models showed that density-dependent reductions in population growth rates were partially due to reduced survival. Wintering eagles in British Columbia fed heavily on chum salmon (Oncorhynchus keta) runs, and then switched to birds in late winter, when mortality was highest. Eagles tended to arrive after the peak in salmon availability at streams in BC as part of a migration associated with salmon streams from Alaska to northern Washington. Eagles were most abundant in southern BC during cold Alaskan winters and in years of high chum salmon availability. We suggest that eagle populations in the Pacific Northwest are currently partially limited by density on the breeding grounds and partially by adult mortality in late winter, likely due to reduced late winter salmon stocks forcing eagles to exploit more marginal prey supplies. Larger eagle populations have affected some local prey populations.Journal of Wildlife Management 11/2011; · 1.64 Impact Factor
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ABSTRACT: Pesticides are toxic chemicals used to control pests, weeds and pathogens. Three quarters of all pesticides are employed in agricultural production, particularly in developed countries, in an effort to mitigate crop damage endured by intensive agriculture. However, after more than 60 years of worldwide usage, their side-effects on terrestrial ecosystems – even when applied as recommended – are obvious. This chapter examines the ecological problems caused by specific chemicals/groups, so that this awareness may help improve agricultural practices through appropriate risk management. Fungicides alter the microbial-fungi communities responsible for the recycling of nutrients in the soil, and copper fungicides are toxic to earthworms and other animals. The routine application of herbicides has produced a net loss of plant biomass and biodiversity in many landscapes, which indirectly reduces the associated arthropod communities and leads to population declines in many species of birds, and possibly amphibians too, due to lack of food. Insecticides are very toxic to most invertebrates in the soil, birds and small mammals, causing significant reductions in their populations and disturbing the trophic structure of their communities. Persistent pesticides accumulate in soil and concentrate through the trophic chain, causing a plethora of sublethal effects which are negative for the survival of individuals as well as the viability of their populations; the long term effects of DDT and cyclodiene poisoning in birds is still an ecological issue despite more than 30 years of not being applied in most developed countries. While pesticides have increased our agricultural productivity and helped feed the current human population, the price of this productivity is being paid by the Earth’s ecosystems at large.01/2011: pages 63-77; , ISBN: 978-1-60805-121-2