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Environmental Variation and Cohort Effects in an Antarctic PredatorUnderstanding the potential influence of environmental variation experienced by animals during early stages of development on their subsequent demographic performance can contribute to our understanding of population processes and aid in predicting impacts of global climate change on ecosystem functioning. Using data from 4,178 tagged female Weddell seal pups born into 20 different cohorts, and 30 years of observations of the tagged seals, we evaluated the hypothesis that environmental conditions experienced by young seals, either indirectly through maternal effects and/or directly during the initial period of juvenile nutritional independence, have long-term effects on individual demographic performance. We documented an approximately 3-fold difference in the proportion of each cohort that returned to the pupping colonies and produced a pup within the first 10 years after birth. We found only weak evidence for a correlation between annual environmental conditions during the juvenile-independence period and cohort recruitment probability. Instead, the data strongly supported an association between cohort recruitment probability and the regional extent of sea ice experienced by the mother during the winter the pup was in utero. We suggest that inter-annual variation in winter sea-ice extent influences the foraging success of pregnant seals by moderating the regional abundance of competing predators that cannot occupy areas of consolidated sea ice, and by directly influencing the abundance of mid-trophic prey species that are sea-ice obligates. We hypothesize that this environmentally-induced variation in maternal nutrition dictates the extent of maternal energetic investment in offspring, resulting in cohort variation in mean size of pups at weaning which, in turn, contributes to an individual?s phenotype and its ultimate fitness. These linkages between sea ice and trophic dynamics, combined with demonstrated and predicted changes in the duration and extent of sea ice associated with climate change, suggest significant alterations in Antarctic marine ecosystems in the future.
Document ID
20110022991
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Garrott, Robert A. (Montana State Univ. Bozeman, MT, United States)
Rotella, Jay J. (Montana State Univ. Bozeman, MT, United States)
Siniff, Donald B. (Minnesota Univ. Saint Paul, MN, United States)
Parkinson, Claire L. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Stauffer, Glenn E. (Montana State Univ. Bozeman, MT, United States)
Date Acquired
August 25, 2013
Publication Date
January 1, 2011
Subject Category
Life Sciences (General)
Report/Patent Number
GSFC.JA.5184.2011
Report Number: GSFC.JA.5184.2011
Funding Number(s)
CONTRACT_GRANT: NSF OPP-0635739
Distribution Limits
Public
Copyright
Public Use Permitted.

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