Shrouded by clouds, mist, and snow for much of the year, high mountain lakes are ideal locations to assess environmental change affecting the high country of the Pacific Northwest. Mountain lakes integrate the effects of multiple stressors, such as climate change, air pollution, and visitor impacts, from over a broad area into a suite of chemical and biological characteristics that essentially make them living Petri dishes. Given their high elevation, mountain lakes are particularly susceptible to the effects of atmospheric pollution. Pollutants such as nitrogen, ammo-nium, sulfur, and various contaminants (e.g. mercury, semi-volatile organic pollutants) are deposited from air masses that originate from industrialized areas. Mount Rainier National Park receives pollutants from the rapidly growing Puget Sound, Portland and Frasier Valley metropolitan areas as well as from trans-Pacific sources. Fish stocking in all three parks has altered native lake food web structure and nutrient dynamics. Global climate change is predicted to impact mountain lakes systems in a variety of ways. Increased air and water temperature can change the timing and duration of ice cover. Since these systems are ice-free only a fraction of the year, change in ice cover will fundamentally alter foodweb interactions, species diversity, and nutrient dynamics. Increased temperatures may also change the timing and amount of glacial and snow melt-water inputs to lakes, causing changes to hydrologic regimes that affect nutrient concentrations and foodwebs. Amphibians are essential components of mountain lake foodwebs. Their abundance and diversity can be altered by the introduction of non-native predators and diseases. Several diseases affecting amphibians are thought to be influenced by global climate change and visitor impacts. Many network lakes have historically been stocked with non-native fish, fundamentally altering biological community structure and nutrient dynamics. Lake monitoring data will provide baseline data to predict future changes in these vital park ecosystems.
This information will provide for a:
- Better understanding of impacts of atmospheric pollution
- Better understanding of impacts of global climate change
- Development of criteria for restoring lakes impacts by non-native species
- Identification of impacts associated with backcountry visitation