Selective herbivory by white-tailed deer is associated with demographic and compositional bottlenecks across forest regeneration stages in the National Capital Region
White-tailed deer ( Odocoileus virginianus ) populations in eastern North America now exceed historical levels, imposing intense browsing pressure on forest regeneration where hunting is limited. Using National Park Service monitoring data (2013–2023) from the National Capital Region Network, we analyzed 9459 seedlings and 6015 saplings of 71 and 64 species, respectively, from 430 plots over 10 years spanning a gradient of low to very-high deer impact. Mixed-effects models that accounted for repeated sampling of plots showed that per-plot seedling richness declined substantially with deer impact ( P < 0.001), and the probability that a plot held any browsable regeneration fell to 0.78 at very-high browse impact. Browsing was species-selective, but less broadly than raw browsing rates imply. After adjustment for height, deer impact, site, and year, only a minority of species differed from the community-average browse rate, with black tupelo ( Nyssa sylvatica ) and American hornbeam ( Carpinus caroliniana ) consistently above the overall average browse rate. Height was a major driver, with a non-monotonic effect: Browse probability peaked near 80 cm and declined in taller stems ( P < 0.001), defining a structural browse window. The sapling:seedling ratios varied among impact levels ( P < 0.001) but were unrelated to browse intensity; ratios for palatable species such as sweet birch ( Betula lenta ) and white ash ( Fraxinus americana ) approached 0 at the seedling-to-sapling transition, whereas the ratio for browse-resistant American beech ( Fagus grandifolia ) exceeded 6. Browsing was associated with reduced sapling vigor (odds ratio 1.34, P = 0.010). Community composition shifted toward browse-tolerant, shade-tolerant species, with American beech rising from 2.7% of seedlings to 25.2% of saplings, an observation of particular concern given the spread of beech leaf disease ( Litylenchus crenatae mccannii ). Our results suggest that chronic deer browsing is a significant component of the cascading constraints on forest regeneration in the region.