Beavers are ecosystem engineers whose dams increase habitat complexity, water retention, and ecological resilience in stream ecosystems; however, beavers have been extirpated from 95% of the streams they once occupied. Beaver dam analogs (BDAs) are increasingly used in the western USA to replicate these functions in degraded ecosystems, yet their effects on food web structure remain poorly understood. We evaluated how BDAs and natural beaver dams influence fish and macroinvertebrate abundance and biomass, food web structure, and nutrient dynamics in Muddy Creek, a semi-arid stream in southern Wyoming, USA, across four reach types: reference (no structure), natural beaver dams, BDAs, and BDAs enhanced by beaver activity. A before–after–control–impact framework was applied at the BDA reach, where sampling occurred before and after installing BDAs. Stable isotope ratios of carbon (δ¹³C), nitrogen (δ¹⁵N), and sulfur (δ³⁴S) were measured from basal resources and fishes to evaluate shifts in energy pathways and trophic structure. Following BDA installation, fish abundance doubled at the BDA reach relative to pre-installation, while the reference reach showed no comparable increase. Notably, Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus), a native species that is the focus of restoration efforts, colonized the reach after installing BDAs. Preliminary isotope results suggest that fishes were enriched in δ¹⁵N in BDA and beaver-influenced reaches relative to the reference reach, indicating more complex food chains. Carbon isotope values of some fishes were more depleted in the BDA reach, suggesting increased reliance on benthic production. Additionally, sulfur isotope signatures were more enriched in the BDA reach, consistent with enhanced wetland or groundwater connectivity. Patterns in isotope composition and fish responses in BDA and beaver-influenced reaches were more similar to each other than to the reference reach. We are currently analyzing chlorophyll a, nutrients, water quality, and macroinvertebrate density and biomass, which will be presented. Our findings suggest that while BDAs do not fully replace beavers, they rapidly initiate ecological conditions that converge toward those created by natural beaver dams. These results support the use of BDAs as an effective, beaver-mediated restoration tool for rebuilding food web complexity and freshwater resilience.