2023-07-19_REVISION - M2021052 (22)

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Rifle Gravel Pit#1 July 2023 Due to the requirement to provide supplementary water to offset evaporative losses, as well as implementation of stormwater controls and the lack of a surface connection to downstream waters, it is anticipated that the project would result in no measurable or meaningful impact to occupied habitats downstream, and would not measurably or meaningfully impact the listed fish. Given these factors, activities on the parcel would have No Effect for the listed Colorado River endangered fish species and their Critical Habitats. Monarch butterfly—Candidate. Candidate species are not afforded full protection under the ESA; however, the USFWS encourages their consideration in environmental planning, and the USFWS regulatory guidance indicates that Candidate species should be treated similarly to Proposed Species with regard to inter-agency consultation requirements. Informal consultation is requested when a provisional "is likely to jeopardize" determination is reached for a Candidate species (USFWS Sec7 Consultation Handbook, 1998). Monarch butterfly adults feed (gather nectar)from a variety of flowering plant species. However, the monarch butterfly only lays eggs and larvae only feed on milkweeds (Asclepias spp.). The western population overwinters in various coastal sites in central and southern California, and central populations overwinter in Mexico. Monarchs have multiple generations during their migrations; the second, third and fourth generations return to their northern locations in the United States and Canada in the spring. The project area contains migratory and overwintering habitat for the monarch butterfly. Showy milkweed (Asclepias speciosa) is an abundant component of the vegetation in the transitional zones along the boundaries of the wetland areas. Adult butterflies and several monarch caterpillars were observed feeding on milkweeds at the western edge of the property. Western Colorado is not part of a major monarch migration corridor, but the site is being used by migrating adults and as a potential overwintering site for the dispersed population in the area. Proposed development would occur primarily outside the mesic/wetland meadows where the majority of milkweed is located, therefore direct impacts to host plants and habitats would be largely avoided. The project would result in the complete loss of vegetation from approximately 19.00 acres of the property, which would result in potential direct impacts to chrysalis and caterpillars and reduce the foraging vegetation available to adult butterflies. This may result in minor, localized impacts to migrating monarch butterflies, and may reduce the attractiveness of the site as an egg-laying site. Development of the parcel is not likely to jeopardize this Candidate species, as the project may affect individuals but is not expected to alter the species' overall range and life history patterns. USFWS consultation is not required by ESA for Candidate species where an action is not likely to jeopardize the species' existence. Silverspot Butterfly. During the spring of 2022, the USFWS proposed to list the silverspot butterfly as threatened. Primary threats to the silverspot butterfly are habitat loss and fragmentation, climate change, incompatible livestock grazing, and human impacts to wetlands and associated hydrology. The butterfly requires moist open meadows with vegetation for shelter. Butterfly larva feed exclusively on the bog violet(Viola nephraphylla). Surveys at the site were conducted prior to the proposed listing, therefore SGM staff did not explicitly evaluate the potential suitability of the property for silverspot butterfly, or specifically look for bog violet. However, extensive detailed vegetation surveys were undertaken as part of the wetland delineation process, and no bog violet has been found on the site. Activities on the parcel are not expected to directly impact effective habitats since the wetland areas that constitute habitat for the species will be avoided, and the project is not expected to change the existing hydrology that supports these wetlands due to the 57