The role of winter phenology in shaping the ecology of freshwater fish and their sensitivities to climate change
- PDF / 713,927 Bytes
- 21 Pages / 595.276 x 790.866 pts Page_size
- 13 Downloads / 180 Views
Aquatic Sciences
OVERVIEW
The role of winter phenology in shaping the ecology of freshwater fish and their sensitivities to climate change B. J. Shuter • A. G. Finstad • I. P. Helland I. Zweimu¨ller • F. Ho¨lker
•
Received: 7 November 2011 / Accepted: 4 August 2012 Springer Basel AG 2012
Abstract Thermal preference and performance provide the physiological frame within which fish species seek strategies to cope with the challenges raised by the low temperatures and low levels of oxygen and food that characterize winter. There are two common coping strategies: active utilization of winter conditions or simple toleration of winter conditions. The former is typical of winter specialist species with low preferred temperatures, and the latter is typical of species with higher preferred temperatures. Reproductive strategies are embodied in the phenology of spawning: the approach of winter conditions cues reproductive activity in many coldwater fish species, while the departure of winter conditions cues reproduction in many cool and warmwater fish species. This cuing system promotes temporal partitioning of the food resources available to young-of-year fish and thus supports high diversity in freshwater fish communities. If the
B. J. Shuter Harkness Laboratory of Fisheries Research, Ontario Ministry of Natural Resources, Peterborough, Canada B. J. Shuter Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto M5S3G5, Canada A. G. Finstad I. P. Helland Norwegian Institute for Nature Research, P.O. Box 5685, Sluppen, 7485 Trondheim, Norway I. Zweimu¨ller Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria F. Ho¨lker (&) Leibniz Institute of Freshwater Ecology and Inland Fisheries, 12587 Berlin, Germany e-mail: [email protected]
zoogeographic distribution of a species covers a broad range of winter conditions, local populations may exhibit differences in their winter survival strategies that reflect adaptation to local conditions. Extreme winter specialists are found in shallow eutrophic lakes where long periods of ice cover cause winter oxygen levels to drop to levels that are lethal to many fish. The fish communities of these lakes are simple and composed of species that exhibit specialized adaptations for extended tolerance of very low temperatures and oxygen levels. Zoogeographic boundaries for some species may be positioned at points on the landscape where the severity of winter overwhelms the species’ repertoire of winter survival strategies. Freshwater fish communities are vulnerable to many of the shifts in environmental conditions expected with climate change. Temperate and northern communities are particularly vulnerable since the repertoires of physiological and behavioural strategies that characterize many of their members have been shaped by the adverse environmental conditions (e.g. cool short summers, long cold winters) that climate change is expected to mitigate. The responses of these strategies to the ra
Data Loading...
