title: Estimating the effects of 17α-ethinylestradiol on stochastic population growth rate of fathead minnows: a population synthesis of empirically derived vital rates.
abstract: Urban freshwater streams in arid climates are wastewater effluent dominated ecosystems particularly impacted by bioactive chemicals including steroid estrogens that disrupt vertebrate reproduction. However, more understanding of the population and ecological consequences of exposure to wastewater effluent is needed. We used empirically derived vital rate estimates from a mesocosm study to develop a stochastic stage-structured population model and evaluated the effect of 17α-ethinylestradiol (EE2), the estrogen in human contraceptive pills, on fathead minnow Pimephales promelas stochastic population growth rate. Tested EE2 concentrations ranged from 3.2 to 10.9 ng L(-1) and produced stochastic population growth rates (λ S ) below 1 at the lowest concentration, indicating potential for population decline. Declines in λ S compared to controls were evident in treatments that were lethal to adult males despite statistically insignificant effects on egg production and juvenile recruitment. In fact, results indicated that λ S was most sensitive to the survival of juveniles and female egg production. More broadly, our results document that population model results may differ even when empirically derived estimates of vital rates are similar among experimental treatments, and demonstrate how population models integrate and project the effects of stressors throughout the life cycle. Thus, stochastic population models can more effectively evaluate the ecological consequences of experimentally derived vital rates.
authors.affiliation: Colorado Cooperative Fish and Wildlife Research Unit, Department of Fish, Wildlife and Conservation Biology, Colorado State University, 201 Wagar Hall, Fort Collins, CO, 80523, USA. ar.schwindt@gmail.com.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Schwindt
authors.affiliation: Colorado Cooperative Fish and Wildlife Research Unit, Department of Fish, Wildlife and Conservation Biology, Colorado State University, 201 Wagar Hall, Fort Collins, CO, 80523, USA.|United States Geological Survey, Colorado Cooperative Fish and Wildlife Research Unit, Colorado State University, Fort Collins, USA.
authors.forename: Dana L
authors.initials: DL
authors.lastname: Winkelman
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D004784:Environmental Monitoring / Q000379:methods*; D004967:Estrogens; D004997:Ethinyl Estradiol / Q000633:toxicity*; D005260:Female; D005618:Fresh Water; D008297:Male; D011158:Population Growth; D012098:Reproduction; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D004967:Estrogens; D014874:Water Pollutants, Chemical; D004997:Ethinyl Estradiol
keywords: Fathead minnow; Freshwater; Model; North America; Pollution; Sensitivity analysis