Invertebrate avoidance and count, Triclopyr (Garlon XRT) concentration, and leaf litter mass loss and quality data from field and microcosm studies in Saskatchewan, Canada

This is the dataset associated with the publication "Environmental Impact of Triclopyr on Habitat Quality in Boreal Rights-of-Way" submitted to Environmental Toxicology and Chemistry in April 2022 and accepted in June 2022: https://doi.org/10.1002/etc.5475. Included are four data files: 1. microcosm study data, including invertebrate counts, mass loss, litter quality, and triclopyr concentrations of litterbags either treated with triclopyr or left untreated and containing either invertebrates or no invertebrates; 2. field study data, which includes mass loss, leaf litter quality, and triclopyr concentrations of litterbags either treated with triclopyr or left untreated and buried in areas either treated with triclopyr or left untreated; 3. invertebrate avoidance study data of triclopyr-treated leaves conducted in the laboratory; 4. In situ triclopyr (Garlon XRT herbicide) data from field collected leaves post-application of triclopyr. Combined, these data explored the indirect impacts of triclopyr on habitat quality of treated boreal rights-of-way through litter mass loss and quality (carbon to nitrogen ratio) and the response of boreal invertebrates (Folsomia candida and Oppia nitens) to treated litter. We did this using a microcosm experiment, where we placed litter either untreated or treated with triclopyr from three boreal tree species (aspen (Populus tremuloides), paper birch (Betula papyrifera), and willow (Salix bebbiana)) in litterbags in microcosms with or without invertebrates under optimal conditions (~20 °C with a 16-hour light and 8-hour dark photoperiod and 60% humidity) and monitored litter mass loss, litter quality (carbon to nitrogen ratio), triclopyr concentration, and invertebrate numbers over time for a total of four months (May-Sept 2019). In addition, we ran invertebrate avoidance tests in May and September 2018 where we placed individuals of boreal invertebrates in containers where half of the leaf litter was treated with triclopyr of varying doses and the other half was left untreated. After 48 hours, we observed the number of invertebrates on each side of the container to determine avoidance. Doses were as follows: for F. candida 0, 1133, 2265, 3398, 4530, 6795, 9060, 10570, 12080, 13590, 15100, 16610 g a.i. ha-1; for O. nitens 0, 2265, 4530, 11325, 13590, 15085, 16625, 18120, 19615, 21155 g a.i. ha-1. Lastly, we conducted a field study whereby we collected willow (Salix bebbiana) either treated with triclopyr or left untreated (control) and constructed litterbags, which were buried in rights-of-way either treated with triclopyr or left untreated. Leaf litter mass loss, litter quality, and triclopyr concentration were monitored from field sites starting 70 days after foliar application of triclopyr (October 2017) until 365 days after treatment (August 2, 2018). See Voinorosky, Standen & Stewart (2022) for more detailed methods.