BackgroundSierra Nevada Network (SIEN) parks protect over 1,200 lakes that have some of the highest water quality in the Sierra Nevada. Highelevation lakes are critical components of the parks’ ecosystems, popular visitor destinations, and habitat for aquatic and terrestrial organisms, including declining amphibian species. However, they are subjected to stressors that have the potential to adversely affect them. The stressors with greatest concern are air pollution (e.g., increased nutrient and acid inputs), climate change, non-native invasive species (e.g., fish), and localized visitor impacts. Sierra Nevada lakes are especially sensitive to changes from these stressors because the waters are very dilute and t hus small changes can result in pronounced environmental effects.
The Sierra Nevada Network Inventory & Monitoring Program worked closely with SIEN parks to develop and implement the lake monitoring project, initiated in 2008 in Sequoia & Kings Canyon and Yosemite national parks. Network parks selected lake ecosystems were selected for monitoring because they are i) valued for their ecological importance, contribution to wilderness character, recreational opportunities, and importance to regional water supplies, ii) threatened by multiple stressors, iii) sensitive to environmental change, and iv) good indicators of changes within the larger watershed. Monitoring was initiated in 2008 in Sequoia, Kings Canyon, and Yosemite national parks.