title: Biases encountered in long-term monitoring studies of invertebrates and microflora: Australian examples of protocols, personnel, tools and site location.
abstract: Monitoring forms the basis for understanding ecological change. It relies on repeatability of methods to ensure detected changes accurately reflect the effect of environmental drivers. However, operator bias can influence the repeatability of field and laboratory work. We tested this for invertebrates and diatoms in three trials: (1) two operators swept invertebrates from heath vegetation, (2) four operators picked invertebrates from pyrethrum knockdown samples from tree trunk and (3) diatom identifications by eight operators in three laboratories. In each trial, operators were working simultaneously and their training in the field and laboratory was identical. No variation in catch efficiency was found between the two operators of differing experience using a random number of net sweeps to catch invertebrates when sequence, location and size of sweeps were random. Number of individuals and higher taxa collected by four operators from tree trunks varied significantly between operators and with their 'experience ranking'. Diatom identifications made by eight operators were clustered together according to which of three laboratories they belonged. These three tests demonstrated significant potential bias of operators in both field and laboratory. This is the first documented case demonstrating the significant influence of observer bias on results from invertebrate field-based studies. Examples of two long-term trials are also given that illustrate further operator bias. Our results suggest that long-term ecological studies using invertebrates need to be rigorously audited to ensure that operator bias is accounted for during analysis and interpretation. Further, taxonomic harmonisation remains an important step in merging field and laboratory data collected by different operators.
authors.affiliation: Faculty of Science and Technology, Federation University Australia, Ballarat, Victoria, 3353, Australia. p.greenslade@federation.edu.au.|Research School of Biology, Australian National University, GPO Box, Canberra, Australian Capital Territory, 0200, Australia. p.greenslade@federation.edu.au.
authors.forename: Penelope
authors.identifier: http://orcid.org/0000-0002-2123-5306
authors.initials: P
authors.lastname: Greenslade
authors.affiliation: Faculty of Science and Technology, Federation University Australia, Ballarat, Victoria, 3353, Australia.
authors.forename: Singarayer K
authors.initials: SK
authors.lastname: Florentine
authors.affiliation: Centre for eResearch and Digital Innovation, Federation University Australia, Ballarat, Victoria, 3353, Australia.
authors.forename: Brigita D
authors.initials: BD
authors.lastname: Hansen
authors.affiliation: Faculty of Science and Technology, Federation University Australia, Ballarat, Victoria, 3353, Australia.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Gell
mesh_terms: D000818:Animals; D001315:Australia; D017377:Diatoms / Q000145:classification*; D004463:Ecology; D004784:Environmental Monitoring / Q000191:economics / Q000379:methods* / Q000706:statistics & numerical data; D004785:Environmental Pollutants / Q000032:analysis; D006801:Humans; D007448:Invertebrates / Q000145:classification*; D059232:Laboratory Personnel / Q000592:standards; D015588:Observer Variation; D011722:Pyrethrins / Q000032:analysis; D011897:Random Allocation; D013997:Time Factors; D000066477:Work Performance / Q000592:standards
chemical_list: D004785:Environmental Pollutants; D011722:Pyrethrins
keywords: Diatoms; Identification; Long-term monitoring; Pyrethrum knockdown; Sweeping; Tasmanian rainforest