Potential Effects of Changing Climate Patterns on Subalpine Lakes in Great Basin National Park

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Great Basin National Park (GRBA), in White Pine County, Nev., has six small subalpine lakes. These lakes are a priority resource for park managers due to their pristine condition and high visitation. The only trout species native to these lakes is the Bonneville cutthroat trout (BCT). In the late 1990s, GRBA began a BCT reintroduction program. The success of this program was one of the major factors in the decision to not list the fish as Threatened under the Endangered Species Act. In 2016, the BCT was extirpated from Strawberry Creek in GRBA by a forest fire. Other BCT populations in GRBA may be threatened by decreases in streamflow. In response, GRBA managers are considering the establishment of one or more breeding populations in the subalpine lakes to restock streams in the future.

Great Basin National Park (GRBA), in White Pine County, Nevada, has six small subalpine lakes. These lakes are a priority resource for park managers due to their pristine condition and high visitation. Since 2009, the National Park Service (NPS) Mojave Desert Network Inventory and Monitoring Program (MOJN I&M) has been collecting water quality and physical limnology data at these lakes.

The only trout species native to GRBA is the Bonneville cutthroat trout (BCT). In the late 1990s, GRBA began a BCT reintroduction program. The success of this program was one of the major factors in the decision to not list the fish as Threatened under the Endangered Species Act. GRBA managers are considering the establishment of one or more breeding populations in the subalpine lakes to restock streams in the future.

The subalpine lakes in GRBA are small (about 0.5-4 acres), shallow (about 2-15 feet deep in late summer), and almost entirely dependent on snowmelt; therefore, these lakes are very sensitive to changes in climate. Climate change models predict that the southwestern United States will experience increased warming, increased variability in precipitation, earlier snowmelt, and changes in the frequency and seasonality of precipitation. Since 2009, the National Park Service (NPS) Mojave Desert Network Inventory and Monitoring Program (MOJN I&M) has been collecting water quality and physical limnology data at these lakes.

Bonneville Cutthroat Trout, Great Basin National Park
(Credit: National Park Service. Public domain.)

In 2016, the BCT was extirpated from Strawberry Creek in GRBA by a forest fire. Other BCT populations may be threatened by decreases in streamflow. GRBA managers are considering the establishment of one or more breeding populations in the subalpine lakes to restock streams in the future. Before breeding populations of BCT can be established in any of the subalpine lakes, the effects of climate change on these lakes must be investigated. For example, in September 2015 the smallest of the six lakes (Dead Lake) was observed to be completely dry for the first time on record.

The USGS Nevada Water Science Center will be using existing data to evaluate the effects of recent (2009-2016) climate events on GRBA lakes, and use these analyses to assess the effects of projected climate patterns on potential BCT habitats. The hydrologic response of the GRBA lakes to recent climate will be characterized using previously published datasets including

  1.  MOJN I&M lake data,
  2.  Natural Resources Conservation Service snow course data, and
  3.  National Weather Service Co-operative Observer Program meteorological data.
Teresa Lake, Great Basin National Park
Stella Lake, Great Basin National Park (Public domain.)

MOJN I&M data at the lakes include

  • stage,
  • water chemistry (major ions, nutrients, acid neutralization capacity),
  • water quality field parameters (annual depth profiles of temperature, pH, specific conductivity, and dissolved oxygen),
  • Secchi depth, and
  • ice-off dates.

A wide range of hydrologic conditions and responses are represented by the short (2009-2016) MOJN I&M data record at the lakes including

  1.  one of the highest snowpack years on record (water year 2011),
  2.  one of the lowest snowpack years on record (water year 2012),
  3.  a year with a near-average snowpack but early spring runoff (water year 2016), and
  4.  a summer with the highest monsoonal precipitation on record (water year 2014).

These recent events present a unique opportunity to evaluate lakes responses to wide ranging hydrological conditions.

Following the approach outlined in recent studies such as Parker and others, Sanchez-Lopez and others, and Preston and others, correlations between the aforementioned hydrologic and hydrochemical conditions at GRBA lakes and climate parameters will be evaluated. For example, we will evaluate correlations between

  1.  late-season total nitrogen concentrations and degree-day warming in the spring,
  2.  lake stage and April 1 snowpack, and
  3.  summer lake stage rises and monsoon-season precipitation.

Using the results of the correlative statistical analyses, lake responses to forecasted changes in climate in the CMIP5 multi-model ensemble will be evaluated. For example, if there is a statistically significant positive correlation between April 1 snowpack and lake level, and regional climate models predict snowpack declines, we would conclude that lake levels are likely to decline.