Over the past several decades, anthropogenic pressures including urban development and climate change decreased the amount of hypersaline lake habitat around the world. However, extensive management efforts throughout recent years transformed Great Salt Lake into an example of how proper management can help retain critical habitat while also providing economic returns. Located in northern Utah, Great Salt Lake sits in one of the deepest portions of the Great Basin. This terminal lake receives input from a 21,500-square-mile watershed. Under average conditions, Great Salt Lake is 75 miles long and 25 miles wide and covers 1,700 square miles. Recent drought conditions and increased upstream diversions throughout the region have reduced the surface area of Great Salt Lake to under 1,000 square miles. Over time, Great Salt Lake has been partitioned into four ecologically distinct bays by the construction of human-made causeways. Despite extensive anthropogenic alterations, Great Salt Lake remains one of the most important inland shorebird habitats throughout all of North America (Oring et al., 2005). Recent waterbird surveys on Great Salt Lake revealed that over 10 million individuals from 338 species utilize the wetlands and uplands associated with the lake each year (Great Salt Lake Ecosystem Program, 2024). One such species is the Snowy Plover (Charadrius alexandrines), which relies on the playas and mudflats surrounding the lake as a staging ground during breeding season. However, over recent years, Snowy Plovers along the Pacific Coast have declined in abundance and are now considered Threatened under the Endangered Species Act, Highly Imperiled by the US Shorebird Conservation Plan, and a Focal Species by US Fish and Wildlife Service (USFWS) Division of Migratory Bird Management. Surveys conducted during the 1992 breeding season suggested the active breeding population of Snowy Plover on the lake was approximately 10,000 individuals (Paton & Edwards, 1992), representing roughly 50% of the entire US Snowy Plover population at the time (Page et al., 1995). However, a subsequent survey conducted in 2008 revealed the population of Snowy Plovers on Great Salt Lake had decreased relative to historic levels (Cavitt, 2008), suggesting more frequent plover monitoring efforts are necessary. The decline in Snowy Plover abundance is likely attributed to the change in suitable habitat around the Great Salt Lake and throughout the rest of their pacific coastal range. The lake's highest recorded elevation since scientists began monitoring lake water levels occurred in the late 1980's when the lake reached ~4,212 ft, whereas by 2008 the lake dropped ~18 ft (US Geological Survey, 2024). This decline in lake elevation resulted in increased exposed shoreline, adding potential Snowy Plover habitat. However, despite the increase in habitable space, the change in shoreline was accompanied by other anthropogenic stressors including urban development and invasive plant species. As of March 2024, the lake elevation is similar to 2008, measuring at ~4,193 ft. However, persistent development of the shoreline and invasion of plant species such as Phragmites, which renders the habitat inaccessible to Snowy Plover, suggest current shoreline habitat differs from that of 2008. There have been no formal lake-wide surveys of Snowy Plover since 2008. Given the changes in shoreline characteristics and that Snowy Plovers are now listed as a Threatened species, it is imperative we develop a more consistent monitoring strategy to ensure Snowy Plovers remain a component of the Great Salt Lake ecosystem moving forward.

1) Assess the amount of viable Snowy Plover habitat across the Great Salt Lake, identifying currently inhabited regions and potential areas that may sustain plovers. 2) Optimize a monitoring protocol that conducts a lake-wide survey assessing the distribution and abundance of breeding Snowy Plovers.

The project will take place throughout the entirety of Great Salt Lake, including both the North and South arms. Snowy Plover populations have decreased rapidly over the last few decades, likely coinciding with the alteration of viable habitat around Great Salt Lake. Drastic changes in shoreline abundance, anthropogenic development, and vegetation across the lake took place since the most recent Snowy Plover survey in 2008. In order to update which regions of Great Salt Lake are most important for Snowy Plovers, a holistic survey must be conducted as soon as possible. The results of this survey will then aid policymakers and biologists aiming to improve or conserve Snowy Plover habitat on Great Salt Lake, while updating the population estimate to determine if their abundance has changed since 2008.

The Division of Wildlife Resources' Great Salt Lake Ecosystem Program (GSLEP) is tasked with monitoring and conserving the lake's ecosystem, including the surrounding wetland and shoreline habitats. Snowy Plovers rely on the lake as critical breeding grounds and play a key role as a charismatic species, generating revenue through ecotourism. This project aims to improve our understanding of the distribution and abundance of Snowy Plovers across Great Salt Lake, providing information that will readily assist the conservation of the species.

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The proposed monitoring program will be based on the protocol developed by the US Fish and Wildlife Service, along with the 2008 survey efforts by Dr. John F. Cavitt from the Avian Ecology Laboratory at Weber State University. First, we will enlist local area experts to designate areas of shoreline around Great Salt Lake as one of three habitat categories: 1) known breeding of Snowy Plovers, 2) having the potential to support breeding, or 3) no potential to support plovers. The sites will include previously surveyed areas according to the Cavitt (2008) protocol, in addition to any new shoreline that changed since 2008. Surveying the entire lake is not feasible and we will therefore rely on a grid system to randomly select survey areas. Once shoreline sites are assigned a category, we will use GIS to subdivide regions into 100-ha sample clusters, comprised of 25 4-ha plots (200x200 m). A random sample of clusters will then be selected for each stratum across the entire lake, representing both occupied and viable plover habitat. Once sample clusters (sites) are selected, each 4-ha plot within a cluster will be visited and the occupancy of Snowy Plovers recorded during the breeding season. After all sites are visited, count data will be extrapolated to estimate the range-wide population size of Snowy Plovers around the Great Salt Lake.

Please see methods section above.

To be determined, but will likely include: Tracy Aviary Sageland Collaborative USFWS The Nature Conservancy

The Snowy Plover monitoring protocol would be incorporated into the annual shorebird survey conducted by the DWR's Great Salt Lake Ecosystem Program, continuing for the foreseeable future.

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