Ecological and metabolomic responses of plants to deer exclosure in a suburban forest

• Published in: Ecology and evolution Vol. 12; no. 11; pp. e9475 - n/a
• Main Authors: Morrison, Janet A., Woldemariam, Melkamu
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.11.2022; John Wiley and Sons Inc; Wiley
• Subjects: Benzoin; Biosynthesis; Browsing; browsing pressure; Chemical Ecology; Chloroform; Community Ecology; Community structure; Deer; Ecological effects; ecometabolomics; Ecophysiology; Flowers & plants; Forests; Functional Ecology; Herbivory; Invasion Ecology; Lindera benzoin; Metabolic pathways; Metabolites; Metabolomics; Nyssa sylvatica; Plant growth; Secondary metabolites; Shrubs; Species; Statistical analysis; suburban forests; Trophic Interactions; Understory; Urban Ecology; white‐tailed deer; United States > US; New Jersey; ecometabolomics; browsing pressure; suburban forests; white‐tailed deer
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.9475

Trees and shrubs in suburban forests can be subject to chronic herbivory from abundant white‐tailed deer, influencing survival, growth, secondary metabolites, and ecological success in the community. We investigated how deer affect the size, cover, and metabolomes of four species in the understory of a suburban forest in central New Jersey, USA: the woody shrubs Euonymus alatus and Lindera benzoin, the tree Nyssa sylvatica, and the semi‐woody shrub Rosa multiflora. For each species, we compared plants in 38 16 m2 plots with or without deer exclosure, measuring proportion cover and mean height after 6.5 years of fencing. We scored each species in all plots for deer browsing over 8 years and assessed selection by deer among the species. We did untargeted metabolomics by sampling leaves from three plants of each species in an equal number of fenced and unfenced plots, conducting chloroform–methanol extractions followed by LC–MS/MS, and conducting statistical analysis on MetaboAnalyst. The proportion of a species browsed ranged from 0.24 to 0.35. Nyssa sylvatica appeared most selected by and susceptible to deer; in unfenced plots, both its cover and mean height were significantly lower. Only cover or height was lower for E. alatus and L. benzoin in unfenced plots, while R. multiflora height was greater. The metabolomic analysis identified 2333 metabolites, which clustered by species but not fencing treatment. However, targeted analysis of the top metabolites grouped by fencing for all samples and for each species alone and was especially clear in N. sylvatica, which also grouped by fencing using all metabolites. The most significant metabolites that were upregulated in fenced plants include some involved in defense‐related metabolic pathways, e.g., monoterpenoid biosynthesis. In overbrowsed suburban forests, variation of deer impact on species' ecological success, potentially mediated by metabolome‐wide chemical responses to deer, may contribute to changes in community structure. Overabundant deer in suburban forests cause stress to understory plants exposed to chronic browsing, which impacts ecological performance and may shift their global metabolome since metabolites involved in stress and defense responses could be affected. In one suburban forest, the size, cover, and metabolomic profiles of four woody and semi‐woody plants were affected by long‐term deer exclosure. Metabolites that differentially accumulated in fenced and unfenced plants plants include some involved in defense‐related metabolic pathways.