Impact of - IDL-BNC @ IDRC - International Development Research ...

For example, searching for carcasses on treated fields is often thought to be a
reliable method of detecting impact. Yet, it has not been ascertained whether
affected wildlife die locally or, if they are able, choose to leave the area and die
further afield (Mineau and Collins 1988).
Compound-specific studies are conducted in several ways. Some involve the
controlled application of a pesticide by the investigators; others may take place
during the normal operational use of the product, with or without the knowledge
of the user. Again, the research question being asked determines which
strategy is most appropriate. As well, considerations of cost and logistics often
weigh heavily in this decision. The interpretation of results will have different
emphasis, depending on whether the application was carefully controlled or
conducted under variable conditions typical of operational use.
Pesticides known to have high acute toxicity and identified routes of exposure
for several species usually prompt these types of investigations. Reports of
wildlife kills connected with the use of a particular pesticide product may also
trigger an enquiry. Common field-testing protocols are listed in Table 4, along
with examples and critiques. An overview by Fite et al. (1988) provides
guidance on most of the study types mentioned. Other recent assessments of
wildlife field-testing can be found in Creaves et al. (1988) and Conservation
Foundation (1989).
Use of reference compounds
It is often impractical or not economically feasible to test every potentially
hazardous pesticide. Extensive studies of one or several products with a
similar pattern of use can prove helpful as benchmarks. Untested related
Table 4. Common field-testing strategies for compound-specific enquiries.
Strategy Protocols or critique Examples
Carcass searches Mineau and Collins 1988 Brewer et al. 1988
Surveys Ralph and Scott 1980 Peakall and Bart 1983
Edwards etal. 1979
Milliken 1988
Use of biomarkers Hill and Fleming 1982 Busby et al. 1989
Mineau and Peakall 1987
Fairbrother et al. 1991
Use of sentinel species Robinson et al. 1988
Monitoring reproduction in - Powell 1984
naturally nesting species Busby et al. 1990
Fox et al. 1989
Multiple approach - Bunyan et al. 1981
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