Integrating the effects of climate variability into conservation strategies for marine mammals.
Johnston, David*,1, Littnan, Charles*,1, Baker, Jason1, 1 NOAA Fisheries - PIFSC, Honolulu, HI, 96822
ABSTRACT- Marine mammals have evolved to deal with climate variability as a natural phenomenon. Shifts in climate are not novel or necessarily unidirectional, but rather continuing processes often oscillating between different states at decadal or longer scales. However, marine mammal populations are increasingly faced with the cumulative effects of climate variability and anthropogenic impacts, which may surpass their ability to cope with change. Conservation strategies for vulnerable species are often developed without accounting for the effects of climate variability and projected environmental trends associated with global change. We present two radically different, but complimentary, examples illustrating the utility of incorporating climate indices or predictions into conservation efforts. The first examines endangered Hawaiian monk seal populations and habitat loss due to projected sea-level rise. The second example involves setting allowable removal levels for exploited harp seal populations subject to periodic, occasionally catastrophic, changes in sea ice cover associated with the North Atlantic Oscillation (NAO). In both cases, climate variability can affect pupping habitat availability and, among other things, increase neonatal mortality and heighten the risk of epizootics. Through forecasting the effects of climate variability on seal habitat, conservation efforts can be focused to best deal with cumulative effects of concurrent climate shifts and human impacts. For monk seals this means managing increasing human-seal interactions in populated regions and mitigating habitat loss in remote areas. For harp seals, patterns in sea ice cover and NAO variability can be incorporated into short- and long-term hunt management models to ensure the sustainability of their populations.
Key words: Climate Variability, Population Ecology, Conservation
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