Mysid population responses to resource limitation differ from those predicted by cohort studies

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 432:115-123 (2011) - DOI: https://doi.org/10.3354/meps09158 Mysid population responses to resource limitation differ from those predicted by cohort studies Jason S. Grear*, Doranne Borsay Horowitz, Ruth Gutjahr-Gobell Atlantic Ecology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Narragansett, Rhode Island 02882, USA *Email: grear.jason@epa.gov ABSTRACT: Effects of anthropogenic stressors on animal populations are often evaluated by assembling vital rate responses from isolated cohort studies into a single demographic model. However, these models are difficult to translate into ecological predictions because stressor effects observed in isolated cohorts may differ from those occurring in populations with overlapping generations. This problem is evident in many areas of stressor–response research, including the burgeoning work on ocean acidification. To address this problem, we compared vital rates in experimental cohorts and populations of the mysid Americamysis bahia at 4 levels of resource limitation. This required development of a novel observational scheme that allows inverse estimation of stage-specific vital rates in mixed-age populations without the use of cohort isolation or marking. Using digitally imaged time series observations of stage abundances, the most strongly supported inverse models indicated opposing (i.e. compensatory) effects of resource limitation on adult survival and juvenile maturation. The model with adult survival response only (i.e. no compensation) was also strongly supported. This contrasts with cohort results, where feeding effects on fecundity were strongest. These results suggest that emphasis in stressor–response studies on early life stages and cohorts of uniformly aged individuals may miss important demographic responses and should be augmented by observations of intact populations, especially as methods such as ours become more available. KEY WORDS: Inverse demography · Zooplankton · Population model · Cohort · Survival · ­Americamysis bahia Full text in pdf format PreviousNextCite this article as: Grear JS, Borsay Horowitz D, Gutjahr-Gobell R (2011) Mysid population responses to resource limitation differ from those predicted by cohort studies. Mar Ecol Prog Ser 432:115-123. https://doi.org/10.3354/meps09158 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 432. Online publication date: June 27, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.