| Each year, billions of birds engage in migratory behavior in response to seasonal changes. During fall migration, many birds consume nutritionally rich fruits with high energy density to satisfy their energy requirements, and rich in antioxidant capacity to alleviate oxidative stress. The goal of this study was to investigate the variation in nutritional content and antioxidant content of fruits from two different years, and compare these with trends in temperature and precipitation during the years. The fruits of 12 shrubs were collected during autumn of 2012 and 2013 in Rochester, NY. Nutrient analyses were used to measure the energy density, fat content, acid detergent fiber content, total soluble solids content, ash content, and water content of these fruits. Extracts of fruits were analyzed using multidimensional fluorescence spectroscopy and parallel factor analysis (PARAFAC), a multiway decomposition method, was used to provide "scores" for fluorescent components in the dataset. Components were then correlated with phenol content and anthocyanin content of fruits, obtained using other analytical methods. No consistent trend in the concentration of any particular analyte or PARAFAC scores was observed. Red Osier Dogwood seemed to produce fruits with lower energy density, fat content, and sum of PARAFAC scores, and higher water and acid detergent fiber content in 2012, which experienced more extreme weather patterns than 2013, but Spicebush showed the opposite trend. Fruits that showed less variation in nutritional content between the two years include the high-quality, native Gray Dogwood, and lower-quality non-native Multiflora Rose and Autumn Olive. The variation in nutritional quality and PARAFAC scores of fruits is likely a result of the degree of resilience of individual plants to fluctuating weather patterns, and variation in growing and ripening time frames for fruits. |
