About three of every four Alaska reports of the nearctic brown lemming come from the North Slope’s wet tundra, with more scattered through Gates of the Arctic National Park and Preserve and Noatak National Preserve. That’s the classic setting for this species: wet sedge meadow and tussock tundra across the Arctic coastal plain and the foothills of the Brooks Range.
These lemmings graze heavily on sedges, grasses, and mosses, and in a boom year that grazing pressure shows up on the ground as visibly cropped vegetation across whole patches of tundra. Arctic foxes and tundra-nesting birds key their own breeding success to how many lemmings are around, so a strong lemming year ripples through much of the rest of the food web.
Records run in a tight midsummer pulse, climbing through June and peaking in August before dropping to almost nothing by fall. That’s less about the lemmings vanishing and more about the short window when both lemmings and the people counting them are above ground on the tundra.
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