Riparian and groundwater-dependent ecosystems of the Humboldt-Toiyabe National Forest: An assessment of current conditions

Abstract

This assessment provides information on the conditions of riparian and groundwater-dependent ecosystems in the Humboldt-Toiyabe National Forest (HTNF). We summarized dominant riparian community types and described riparian fish and wildlife habitat. We used peer-reviewed literature, data from the National Forest and other partners, and site visits to inventory and map the distribution of riparian and groundwater-dependent ecosystems, as well as to evaluate the status of five key ecosystem characteristics: (1) surface water and groundwater fluctuations, (2) water quality, (3) channel and floodplain dynamics, (4) spring runout channel condition, and (5) composition and structure of riparian and groundwater-dependent ecosystems. Extensive riparian ecosystems were found in the Northern Mountains, Ruby Mountains, and Sierra Nevada. Springs are abundant across the Forest, and the density of fens is greatest in the Sierra Nevada and Ruby Mountains. Streams in the HTNF likely maintain high water quality, despite widespread alteration of hydrologic fluctuations and channel dynamics. The composition and structure of riparian vegetation is consistent across the Forest. Although expected species and communities are present, unsuitable levels of native and non-native species occur. We determined that grazing and road infrastructure were primary stressors to riparian and groundwater-dependent ecosystems. Our results support the ecosystem assessment completed during the forest plan revision process and can help inform decision-making related to the restoration and maintenance of riparian and groundwater-dependent ecosystems on the Humboldt-Toiyabe National Forest.

Citation

Smith, D.M.; Warren, S.D.; Driscoll, K.P. 2024. Riparian and groundwater-dependent ecosystems of the Humboldt-Toiyabe National Forest: An assessment of current conditions. Gen. Tech. Rep. RMRS-GTR-441. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 350 p. https://doi.org/10.2737/RMRS-GTR-441.