Amy Larsen, Melanie J. Flamme, David K. Swanson, Sarah C. Swanson
While flying loon surveys in Bering Land Bridge National Preserve in 2018, biologists witnessed widespread drying of coastal lakes, the likely consequences of a warming climate. Six sizeable lakes used by Yellow-billed, Pacific and Red-throated Loons drained rapidly (Figures 1a and 1b). Left behind were barren mudflats bereft of loons; gone were the fish, invertebrates and vegetation that provide cover and nourishment to the birds while nesting and chick-rearing. Bering Land Bridge NP is one of a handful of regions throughout the Circumarctic that contain lakes suitable for Yellow-billed Loons. Scientists were surprised by the large number, size and close proximity of the drained lakes, and were left wondering if this was an unusual event, and whether it would impact loon populations in the area.
Figure 1a. A large lake where Yellow-billed Loons nest in Bering Land Bridge National Preserve in June 2009.
Credit: NPS/Melanie Flamme
Figure 1b. The same lake in September 2018 catastrophically drained sometime between late June and early September.
Credit: NPS/Sarah Swanson
As top predators in lake ecosystems, Yellow-billed Loons are sentinels, acting as early indicators of ecological changes that Alaskan wildlife are likely to see in the coming years as climate warming continues. So far, the Yellow-billed Loon population in Bering Land Bridge NP appears relatively stable (Schmidt et al. 2014). Will that trend hold in the future? How will loons cope with the widespread draining of lakes? We will continue monitoring lakes and loons to better understand these rapid changes occurring in the Arctic.
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