Environmental response of upper trophic-level predators reveals a system change in an Antarctic marine ecosystem
- 22 February 2001
- journal article
- Published by The Royal Society in Proceedings Of The Royal Society B-Biological Sciences
- Vol. 268 (1465) , 377-384
- https://doi.org/10.1098/rspb.2000.1371
Abstract
Long-term changes in the physical environment in the Antarctic Peninsula region have significant potential for affecting populations of Antarctic krill (Euphausia superba), a keystone food web species. In order to investigate this, we analysed data on krill-eating predators at South Georgia from 1980 to 2000. Indices of population size and reproductive performance showed declines in all species and an increase in the frequency of years of low reproductive output. Changes in the population structure of krill and its relationship with reproductive performance suggested that the biomass of krill within the largest size class was sufficient to support predator demand in the 1980s but not in the 1990s. We suggest that the effects of underlying changes in the system on the krill population structure have been amplified by predatorinduced mortality, resulting in breeding predators now regularly operating close to the limit of krill availability. Understanding how krill demography is affected by changes in physical environmental factors and by predator consumption and how, in turn, this influences predator performance and survival, is one of the keys to predicting future change in Antarctic marine ecosystems.Keywords
This publication has 20 references indexed in Scilit:
- Krill population dynamics at South Georgia 1991-1997, based on data from predators and netsMarine Ecology Progress Series, 1999
- Diet, provisioning and productivity responses of marine predators to differences in availability of Antarctic krillMarine Ecology Progress Series, 1999
- Interannual variability of the South Georgia marine ecosystem: biological and physical sources of variation in the abundance of krillFisheries Oceanography, 1998
- Interannual variability in krill abundance at South GeorgiaMarine Ecology Progress Series, 1997
- Krill caught by predators and nets: differences between species and techniquesMarine Ecology Progress Series, 1996
- Recruitment of Antarctic krill Euphausia superba and possible causes for its variabilityMarine Ecology Progress Series, 1995
- Pup production and distribution of breeding Antarctic fur seals (Arctocephalus gazella) at South GeorgiaAntarctic Science, 1993
- Growth and longevity of krill during the first decade of pelagic whalingNature, 1986
- Seals and whales of the Southern OceanPhilosophical Transactions of the Royal Society of London. B, Biological Sciences, 1977
- Growth of a fur seal populationPhilosophical Transactions of the Royal Society of London. B, Biological Sciences, 1977