Central Appalachian streams with drainage from surface mining sites have increased Cl-, Ca2+, and SO42- ion concentrations, resulting in elevated specific conductivity (SC) gradients (18-1,185 μS/cm). Elevated SC decreases mostly mayfly genera that are scrapers but this loss does not change total macroinvertebrate secondary production despite increased chlorophyll-a concentration. Instead, salt-tolerant shredder, collector, and predator production increased with increasing periphyton chlorophyll-a. We are now investigating how the contribution of basal food resources changes with SC among scrapers and shredders. We predicted that shredders and collectors are supported by more a suite of ion subsidized primary production in high-SC streams where the remaining macroinvertebrates experience ionic and osmoregulatory stress. To test this, we quantified the trophic basis of insect production using natural abundance of nitrogen (N) and carbon (C) stable isotopes and their presumed food resources of coarse benthic organic matter (CBOM), fine benthic organic matter (FBOM), and periphyton. All basal resources had higher annual average δ13C and δ15N values along an increasing SC gradient with some seasonal variation, particularly CBOM that was lower in spring and autumn. Coarse Benthic Organic Matter δ13C and δ15N were different from FBOM and periphyton but FBOM and periphyton displayed isotopic overlap. Still, scrapers and shredders had a greater % contribution to biomass from periphyton and FBOM in streams with greater SC. We will present the contribution of resources to dominant scraper and shredder production and explore these relationships with streamwater ion concentrations to characterize the role of salts in resource transfer to macroinvertebrates.