Characterizing and Monitoring the Water Properties and Dynamics of Lhù’ààn Mǟn (Kluane Lake), Yukon, in the Face of Climate Change

C CHANGE AMPLIFICATION in the Arctic is increasing the impacts on both terrestrial and aquatic systems in northern regions (Serreze and Barry, 2011; Vincent et al., 2011). The impacts on large lakes are of particular interest: these waterbodies hold a significant portion of the North’s freshwater, provide habitat and travel corridors for many species, regulate hydrological processes and local climate, and have significant cultural value (Evans, 2000; Rouse et al., 2005; Vincent et al., 2011; Cott et al., 2016; Reist et al., 2016). Studies have shown that these large lakes are sensitive to incremental and cumulative climatic changes and that small shifts in physical, chemical, and biological water properties may have significant consequences for surrounding ecosystems and communities (Magnuson et al., 2000; Smol et al., 2005; Rosenzweig et al., 2007; Adrian et al., 2009; Heino et al., 2009; Mueller et al., 2009; Schindler, 2009). For example, increasing air temperatures may cause longer open-water seasons and increased water temperatures, which affect oxygen availability, productivity, and habitat for aquatic species (Vincent, 2009; Prowse et al., 2011). Glacierinfluenced systems are also susceptible following changes in the contribution of glacial meltwater to headwater lakes (Shugar et al., 2017). Despite rapid change in the North, as well as the general importance of these large lake systems to ecosystems, climate, and communities, scientific knowledge of the dynamics and water properties of these systems is still limited (Evans, 2000; Cott et al., 2016; Reist et al., 2016). Baseline studies, a better understanding of general lake dynamics, and consistent monitoring are needed in order to investigate how climate change may be affecting large northern lakes. Yukon is home to many large lakes, the largest being Lhù’ààn Mǟn (Kluane Lake), located in the southwest of the territory at the foot of the St Elias Mountains (Fig. 1). Lhù’ààn Mǟn lies within the traditional territories of the Kluane First Nation and White River First Nation and borders those of the Champagne and Aishihik First Nations. The lake is important to local communities for fishing, cultural activities, and travel. Lhù’ààn Mǟn also provides an excellent case study for assessing the potential impacts of climate change on the properties of large northern lake systems. The southwest Yukon has experienced significant warming over the past few decades, which has resulted in changes to the surrounding vegetation (Danby et al., 2011; Myers-Smith and Hik, 2017) and cryosphere (including snowcover, permafrost degradation and glacier recession (Bonnaventure and Lewkowicz, 2011; Flowers et al., 2014; Bokhorst et al., 2016) with inevitable consequences for the hydrosphere (Streicker, 2016). As is true for many other large northern lakes, historical scientific data for Lhù’ààn Mǟn is limited: some temperature profiles were collected in the 1980s by Dr. Eddy Carmack (pers. comm. 2014), and limited point sampling has been completed by the Fish and Wildlife Branch, Government of Yukon, during routine fish surveys (Barker et al., 2014), as well as by university-based researchers (Crookshanks and Gilbert, 2008). Over the course of 2013 – 14, Dr. David Hik and I met several times with representatives of the Kluane First Nation (KFN), the Dän Keyi Renewable Resources Council (DKRRC), and local community members to identify common research interests. One of these was to investigate how climate change may be affecting the water properties of Lhù’ààn Mǟn. Given the current and historical lack of scientific water property data, our first objective was to conduct a FIG. 1. Location of Lhù’ààn Mǟn (Kluane Lake), Yukon Territory,