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

Abstract

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.

Distribution and diversity of diatom assemblages in surficial sediments of shallow lakes in Wapusk National Park (Manitoba, Canada) region of the Hudson Bay Lowlands

“…In addition, catchment disturbance by lesser snow geese likely enhances erosion and delivery of dissolved constituents in some lakes, such as WAP 20 and WAP 21 (MacDonald et al. ). IPP and BSF lakes are generally surrounded by more luxurious vegetation and peat deposits, which probably results in more acidic organic inputs into their waters.…”

“…The CF ecozone is also known to be an important breeding ground for the Lesser Snow Goose ( Chen caerulescens caerulescens ) population, which has been identified as a major factor controlling the seasonal carbon cycle and evolution of CF lakes “WAP 20” and “WAP 21” (MacDonald et al. , ).…”

Paleolimnology of thermokarst lakes: a window into permafrost landscape evolution

“…Yet, useful information about carbon dynamics within permafrost landscapes in the past can be obtained from thermokarst lake archives. Key potential measures include carbon inventories and accumulation rates (through the loss-on-ignition technique), fossil biomarkers (e.g., pigments, fatty acids) indicating the presence of methanogenic or methanotrophic bacteria, and sedimentary geochemistry related to the different fractions and sources of organic matter (e.g., organic carbon and nitrogen elemental and stable isotope composition, organic matter biomarkers; Korosi et al 2015;MacDonald et al 2015;McGowan et al 2016). Moreover, sources and accumulation rates of mineral and organic particles in lakes can be characterized by sediment trap techniques, which have not yet been widely used in thermokarst aquatic systems (Coulombe et al 2016).…”

“…MacDonald et al (2015) combined paleolimnological analyses with three years of water chemistry measurements to assess the dual effects of climate warming and LSG population expansion on three thermokarst lakes -two that were in catchments strongly disturbed by the LSG based on field observations and one that had no visual evidence of recent LSG disturbance in its catchment. Results identified limnological phases characterized by regime shifts in productivity, nutrient cycling, and aquatic habitat during the past two centuries (Table 1).…”

Invertebrate communities of the High Arctic ponds in Hornsund

“…Climate warming causes many bird populations to expand, resulting in nu− trient enrichment and deterioration of natural sites in the Arctic (Keatley et al 2009). For example, geese can have major fecal impact on limnology of shallow Arctic coastal ponds (Côté et al 2010;MacDonald et al 2014).…”