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The effect of ivermectin on the invertebrate fauna associated with cow dung
Author(s) -
McCracken D.I.,
Foster G.N.
Publication year - 1993
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620120109
Subject(s) - ivermectin , fauna , pasture , biology , invertebrate , scarabaeidae , cow dung , ecotoxicology , ecology , larva , zoology , agronomy , fertilizer
On each of four dates between May and September 1988, ivermectin was mixed into 60 × 1 kg pats of cattle dung, such that each contained 2, 1, 0.5, or 0 mg ivermectin per kilogram. The pats were then placed on pasture in a stratified, random, block plot and exposed for 15, 30, 45, 60, or 90 d. Twelve pats and a soil sample from below each were lifted at the end of these exposure periods and invertebrates extracted from both dung and soil. This study concentrated on the differences between experimental pats with regard to the numbers and types of Diptera and Coleoptera present. A total of 65 taxa were identified, and the data sets obtained for the dung and the soil were analyzed separately, using two multivariate techniques—TWINSPAN and DECORANA. The major factors determining the fauna of the dung pats and of the soil below them were found to be length of exposure on pasture, exposure date, and ivermectin presence/absence. The presence of ivermectin in the dung markedly changed the fauna in and below treated pats, particularly affecting cyclorrhaphan fly larvae. It is suggested that the incorporated multivariate methods have great potential for use in environmental contamination studies, as they analyze complex data sets objectively and allow the identification of faunal characteristics of treated and untreated sites.