Glacier National Park Directs Change

A juvenile bull trout swims above a juvenile Yellowstone cutthroat trout in Glacier National Park.

USGS

In Glacier National Park, water temperatures are warming and projected to continue to increase due to climate change-driven loss of glaciers and warming air temperatures. Meanwhile, invasive lake trout (Salvelinus namaycush) have compromised lakes and streams in the park and are extirpating local populations of native bull trout (Salvelinus confluentus), a species listed as threatened under the Endangered Species Act. 

Bull trout reproduction, growth, and survival require the coldest water temperatures of any inland salmonid species. In recent years it has become clear that, without action, Glacier bull trout face the prospect not only of continuing genetic erosion, but of extirpation from the park. Park staff therefore made the decision in an important bull trout drainage—Logging Creek—to move the dwindling population upstream above an impassable waterfall into Grace Lake, an ecosystem already altered by past introductions of Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), to conserve the species in cooler waters that they need without the competition from lake trout. 

This intervention recognizes that completely resisting change in lower Logging Creek— i.e., keeping the stream’s bull trout population as it was, where it was—is not possible and instead seeks to direct the ecological trajectory and at least retain the species somewhere in the park by moving the population to an area where it has never before occurred. At the same time, this action also directs change in the ecology of upper Logging Creek, an area already been substantially altered by past human activity (historical introduction of Yellowstone cutthroat trout, which do not threaten bull trout). The park continues to supplement this management action by rearing and introducing additional individuals, monitoring the introduced population, and evaluating their translocation strategies. 

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Explore more:

• 

  Warming up to Adaptation: Glacier National Park

  In Glacier National Park, bull trout are threatened by both invasive species and increasingly warming waters. Explore how park managers are using a bold strategy to provide conditions better suited for the survival of the species.

  Duration:

  5 minutes, 28 seconds

• Saving Bull Trout (NPS)
• Translocation of imperiled fishes: Conservation introduction of threated bull trout in Glacier National Park (USGS Northern Rocky Mountain Science Center)

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National Park Service and U.S. Geological Survey scientists gill net lake trout from Quartz Lake in an effort to eradicate the species from Glacier National Park.

NPS/Jacob Frank