Limnological regime shifts caused by climate warming and Lesser Snow Goose population expansion in the western Hudson Bay Lowlands (Manitoba, Canada)

• Published in: Ecology and evolution 2015-02, Vol.5 (4), p.921-939
• Main Authors: MacDonald, Lauren A., Farquharson, Nicole, Merritt, Gillian, Fooks, Sam, Medeiros, Andrew S., Hall, Roland I., Wolfe, Brent B., Macrae, Merrin L., Sweetman, Jon N.
• Format: Article
• Language: English
• Subjects: Algae; Aquatic birds; Aquatic ecosystems; Aquatic habitats; Biofilms; Carbon; Carbon dioxide; Carbon isotopes; Chen caerulescens; Climate; Climate change; climate warming; Cyanobacteria; diatoms; Disturbance; Ecological monitoring; Engineering research; Environmental changes; Glaciation; Global warming; Habitats; Hudson Bay Lowlands; Landscape; Lead isotopes; Lesser Snow Goose; limnology; Lowlands; National parks; Nesting; Nitrogen; nitrogen isotopes; Nutrient cycles; Nutrients; Original Research; paleolimnology; Parks & recreation areas; Photosynthesis; Pigments; Polar environments; Ponds; Population growth; Productivity; Sediments; Studies; Tundra; tundra pond; Vegetation
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.1354

Shallow lakes are dominant features in subarctic and Arctic landscapes and are responsive to multiple stressors, which can lead to rapid changes in limnological regimes with consequences for aquatic resources. We address this theme in the coastal tundra region of Wapusk National Park, western Hudson Bay Lowlands (Canada), where climate has warmed during the past century and the Lesser Snow Goose (LSG; Chen caerulescens caerulescens) population has grown rapidly during the past ~40 years. Integration of limnological and paleolimnological analyses documents profound responses of productivity, nutrient cycling, and aquatic habitat to warming at three ponds (“WAP 12”, “WAP 20”, and “WAP 21″), and to LSG disturbance at the two ponds located in an active nesting area (WAP 20, WAP 21). Based on multiparameter analysis of 210Pb‐dated sediment records from all three ponds, a regime shift occurred between 1875 and 1900 CE marked by a transition from low productivity, turbid, and nutrient‐poor conditions of the Little Ice Age to conditions of higher productivity, lower nitrogen availability, and the development of benthic biofilm habitat as a result of climate warming. Beginning in the mid‐1970s, sediment records from WAP 20 and WAP 21 reveal a second regime shift characterized by accelerated productivity and increased nitrogen availability. Coupled with 3 years of limnological data, results suggest that increased productivity at WAP 20 and WAP 21 led to atmospheric CO2 invasion to meet algal photosynthetic demand. This limnological regime shift is attributed to an increase in the supply of catchment‐derived nutrients from the arrival of LSG and their subsequent disturbance to the landscape. Collectively, findings discriminate the consequences of warming and LSG disturbance on tundra ponds from which we identify a suite of sensitive limnological and paleolimnological measures that can be utilized to inform aquatic ecosystem monitoring. This paper employs a combination of water chemistry and paleolimnological data to determine limnological responses of climate warming and the Lesser Snow Goose (LSG) population expansion on shallow tundra ponds in Wapusk National Park, which we identify as regime shifts. The study design compares data from three ponds, two of which have been disturbed by the LSG population and one which has not.