Tracking anthropogenic- and climatic-related environmental changes in the remaining habitat lakes of the endangered Atlantic whitefish (Coregonus huntsmani) using palaeolimnological techniques

1. Atlantic whitefish (Coregonus huntsmani) is a critically endangered species whose remaining habitat is restricted to three lakes near Bridgewater, Nova Scotia, Canada. Other lakes in this region have been affected by a variety of environmental changes over the past 150 years (e.g. acidic deposition, eutrophication, and climatic changes); however, the extent of the impact on these remaining Atlantic whitefish lakes, and how the current limnological conditions compare with pre-industrial conditions, is not known. 2. Given the lack of long-term monitoring data, palaeolimnological techniques were used to track environmental changes in these three lakes to infer historic limnological conditions. 3. Results of this study show that acidic deposition has had no significant impact on these lakes (diatom-inferred lakewater pH has changed little over time), nor has the nutrient status of these lakes changed as the sediment profiles have been consistently dominated by oligotrophic diatom taxa. 4. Changes in the dominance of diatom assemblages since similar to 1850, from Aulacoseira distans to Cyclotella stelligera, are correlated with climatic warming (r = 0.48-0.89, P < 0.05). 5. Contrary to initial concerns, these only remaining habitats of the Atlantic whitefish have not yet been affected by acidic precipitation. However, other potential stressors, such as climatic warming and associated limnological changes, may now be affecting the habitat of this endangered species. Copyright (c) 2008 John Wiley & Sons, Ltd.