title: Population-level effects in Amphiascus tenuiremis: contrasting matrix- and individual-based population models.
abstract: Environmental risk assessment (ERA) is generally based on individual-level endpoints, even though protection goals in ERA intend higher biological levels. Population models have the potential to translate individual-level endpoints to population-level responses and range from simple demographic equations to highly complex individual based models (IBMs). The aims of the current study were to develop a matrix model (MM) with the structure and parameterization proposed in the draft OECD guideline "Harpacticoid copepod development and reproduction test with Amphiascus tenuiremis", and an IBM with the same data requirements. Experimental data from lindane exposure from validation studies of the OECD guideline was projected to the population level. Lindane does not only cause effects on survival and reproduction, but also on the time it takes to develop from larvae to adults. The two model approaches were contrasted in terms of their ability to properly project these effects on development. The MM projected smaller effects of the lindane treatments on population growth rate compared to the IBM since in its proposed structure, it did not include the delay in development explicitly. Population-level EC10 for population growth rate in the IBM was at the same level as the most sensitive individual-level endpoint, whereas the EC10 from the MM was not as sensitive. Based on these findings, our conclusion is that the IBM (or an improved MM) should be used for datasets including shifts in development, whereas the simpler MM is sufficient for datasets where only mortality and reproduction are affected, or as a screening tool in lower-tier population-level ERA.
authors.affiliation: Stockholm University, Department of Applied Environmental Science (ITM), Svante Arrhenius väg 8, S-106 91 Stockholm, Sweden.
authors.forename: Elin
authors.initials: E
authors.lastname: Lundström Belleza
authors.affiliation: RWTH Aachen University, ABBt - Aachen Biology and Biotechnology, Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, D-520 74 Aachen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Brinkmann
authors.affiliation: RWTH Aachen University, ABBt - Aachen Biology and Biotechnology, Institute for Environmental Research, Chair of Environmental Biology and Chemodynamics, Worringerweg 1, D-520 74 Aachen, Germany.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Preuss
authors.affiliation: Stockholm University, Department of Applied Environmental Science (ITM), Svante Arrhenius väg 8, S-106 91 Stockholm, Sweden. Electronic address: magnus.breitholtz@itm.su.se.
authors.forename: Magnus
authors.initials: M
authors.lastname: Breitholtz
mesh_terms: D000818:Animals; D033342:Copepoda / Q000187:drug effects / Q000502:physiology*; D001556:Hexachlorocyclohexane / Q000633:toxicity; D007814:Larva / Q000254:growth & development; D008018:Life Cycle Stages / Q000502:physiology; D008962:Models, Theoretical; D011157:Population Dynamics; D012098:Reproduction / Q000187:drug effects; D018570:Risk Assessment / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D001556:Hexachlorocyclohexane
keywords: Harpacticoid copepods; Individual-based model; Lefkovitch matrix model; Lindane; Population dynamics; Population growth rate