To explore potential photoprotective responses to in situ UV exposure, the relative abundance of eight pigments and antioxidants was measured in field samples at the end of the one-year study. Pigment and tocopherol content were quantified by high-performance liquid chromatography (HPLC) in four biological replicates for each of the 57 field samples for a total of 342 HPLC measurements. Approximately 5 mg (about five shoots) of dry, soil-free plant material was collected from each field triplicate (UV-filtered, transmitted, and site-reference) and homogenized in 100% acetone using a FastPrep-24 5G bead beater (MP Biomedicals, Irvine, CA, USA). Additionally, 5-10 shoots of lab cultured S. caninervis were prepared in at least triplicate. After homogenization in acetone, samples were centrifuged at 14,000 g for 30 s. Supernatants were passed through a 0.45 mm nylon filter (part F2504-1, ThermoFisher Scientific, Waltham, MA, USA) prior to injection of 25 µL onto a ProntoSIL 200-5-C30, 5.0 µm, 250 mm × 4.6 mm column equipped with a ProntoSIL 200-5-C30, 5.0 µm, 20 mm × 4.0 mm guard column (Bischoff Analysetechnik, Leonberg, Germany) following the HPLC method and gradient conditions of Dautermann et al. (2020). Tocopherols were measured by fluorescence light detection (FLD) and compared to retention time of commercial tocopherol standards.