Deterring frugivores, sparing pollinators: reflective tapes as a selective mistletoe management tool in urban trees

Urban green spaces are important reservoirs of biodiversity, yet urban host trees are increasingly affected by mistletoe infestations. Because most mistletoes depend entirely on animal vectors for pollination and seed dispersal, interventions targeting these vectors offer a potential management approach. Reflective tapes are a nonlethal bird deterrent widely used in agriculture but have not been tested in urban forestry nor against mistletoe reproduction. We experimentally tested whether reflective tape deterrents reduce pollination and frugivory of the hemiparasitic mistletoe Tristerix corymbosus on urban host trees in central Chile. Using a Before-After-Control-Impact design at three sites (n = 30 plants), we monitored visitation by the hummingbird Sephanoides sephaniodes ; frugivory was assessed with a parallel-groups design at two sites (n = 19) during the fruiting period. Reflective tapes had no detectable effect on hummingbird visitation rate or fruit set, while flower number was a significant positive predictor of pollinator visits. In contrast, tapes significantly reduced total perching events, fruit consumption events, and feces containing seeds – a direct measure of ingestion – although cumulative seed counts on host plants, which are not exclusive to bird-mediated dispersal, were unaffected. These results suggest that reflective tapes disrupt frugivory without a detectable effect on pollination, making them a promising low-cost (USD 0.19 per plant), non-invasive tool for urban mistletoe management. Because tapes did not reduce seed deposition on host branches and new infections were not measured, they should be viewed as a complement to pruning rather than a substitute, prioritizing high-fruit-load mistletoes acting as primary seed sources.