Abstract

Water is a limited and highly valued resource in the semi-arid Great Basin. Surface water sources are often small and widely spaced apart, comprising only 1-3% of the surface area of the overall landscape. Despite their small size, these springs and surrounding wet meadows have a substantial effect on the surrounding environment. Springs provide drinking water, forage and cover for livestock and wildlife, habitat for diversity of plant species and a resource for human-related activities. In recent years, many of these springs have become dewatered due to diversions of groundwater for municipal water and agriculture, and climatic shifts in precipitation affecting recharge. These hydrologic changes can cause a drop in the local water table that promotes a shift in the plant community from wetland-obligates to species that have more drought-tolerance. The root masses of the new plant community are insufficient to secure soils resulting in the erosion of the thalweg. This leads to channelization through the wet meadow, which drives the water table further underground. As degradation progresses, springs and wet meadows lose their ability to store water. The purpose of this thesis is to examine the responses of both the hydrologic and biologic factors to different springbox restoration techniques. Twenty-four spring sites were chosen in the Sheldon National Wildlife Refuge in northwestern Nevada. Each site was randomly assigned one of six different treatment designs. Variables for these studies included: surface soil moisture, soil moisture at varying depths, flow rates, water chemistry, plant community cover and frequency, biomass, wildlife visits and wildlife species numbers. We observed soil moisture increase over the majority of our sites, while flow rates only increased at the control sites. This may indicate that more water is being held in the soils around the spring source instead of being allowed to flow downstream. Biomass increased in four of our six treatments. All treatment types exhibited a similar effect on springs with none having a clearly more restorative effective than any others. This research suggests that springs in the Great Basin have unique characteristics and responses to restoration, and may need individualized approaches. Additionally, studies have shown that it may take many years for plant communities to recover after hydrologic restoration. Yearly variation caused by increased precipitation may be partially responsible for changes in hydrologic and biologic aspects of springs and wet meadows. Further data collection is needed to determine the true extent of treatment and yearly effects on spring restoration. In spite of the need for individualized approaches, restoration is possible. Simple solutions may be sufficient to recover hydrologic processes that maintain ecologic resilience.

Degree

MS

College and Department

Life Sciences; Plant and Wildlife Sciences

Rights

http://lib.byu.edu/about/copyright/

Date Submitted

2019-07-01

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd11325

Keywords

lentic springs, restoration, soil moisture, Great Basin, wet meadow, riparian zone

Language

english

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