[ } Agate Lake Resource Management Plan Environmental Assessment LL±JApni IResponses to Public Comments

LETTER NO. 15 (CONTD.)

maps to delineate that area, Finally, the report was to provide a discussion of the principles of conservation biology that could be used to determine the suitability of sites for restoration or enhancement of the ecosystem and associated rare species.

Vernal Pools

Vernal pools are rain-fed, seasonal wetlands, which are a highly variable ecological phenomenon that occurs widely throughout the world and across North America. (Keely 1996). The distinct and yet variable habitat offered by vernal pools in combination with the geographic isolation of pool systems produces many distinct natural communities with high levels of species endemism. The range of vernal pools worldwide has been classified by the features of the substrate that cause the pooling, along with hydrologic and biotic features.

Study Area

The Agate Desert is a geographic place name applied to the mounded prairie on the floor of the Basin, north of Medford, . The area is presumably named for the sparse prairie vegetation, the relative lack of trees, the poor agricultural quality of the shallow soil, and the agates commonly found on the soil surface. The USGS 7.5 miaute quadrangles for Sams Valley and Eagle Point label as the Agate Desert an area stretching eastward from near the confluence of Bear Creek and the Rogue River, across White City, south of IItte Butte Creek to Antelope Creek and Dry Creek. Elliott and Sammons (1996) expanded on the USGS area by extending a lobe southward across the Jackson County Airport, and they delineated two additional discrete surfaces: a large area between Dry Creek and Antelope Creek, and a smaller surface west of Bear Creek, north of Central Point. The Elliott and Sammons boundary encompassed an area of 21 square miles, defined by the occurrence of four features. These include the alluvial gravel terrace, a yellowish red, well oxidized surface, a shallow duripan, and the presence of patterned ground.

To reasonably discuss the vernal pools of the Agate Desert, this study extends the use of the Agate Desert place name to a larger area, although still centered on the uAgate Desert" as mapped by the USGS. This study refers to the Agate Desert vernal pool landscape to descrjbe a geomorphic surface which is best delineated by the extent of the Agate-Winlo complex soil map unit, described and mapped by the Natural Resources Conservation Service (Johnson 1993). This delineation encompasses additional occurrences of the patterned ground for a total area of 32 square miles. These areas of patterned ground extend from Shady Cove south to Phoenix and from Central Point east to the town of Lake Creek (Figure 1). The largest area will be referred to as the central or core Agate Desert laidscape and has a variety of lobes. The outlying fragments of the surface will be referred to as the Agate Desert vernal pool landscape isolates.

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