Meeting seed demand for landscape-scale restoration sustainably: the influence of seed harvest intensity and site management

Abstract

ABSTRACTNative seed is often collected en masse from remnant ecosystems to supply landscape-scale restoration. Successful large-scale restoration depends on sustained seed yields but also on donor population persistence. Native plants that reproduce solely by seed are especially sensitive to harvesting practices. We addressed the challenge of procuring sufficient seed from remnant sources to restore landscapes while also maintaining remnant populations of native plants. We evaluated: 1) the sustainability of seed harvest at varying intensities in Rudbeckia hirta, a seed-reliant plant; and 2) the contribution of fire in promoting sustainability of seed donor populations. We planted seedlings of R. hirta in a field experiment that manipulated management type (burned or unburned) and harvest intensity (0, 50%, or 100% seed removed), and measured changes in seedling recruitment and seed production among treatments. Moderate intensity harvest and burning did not significantly reduce seedling recruitment, but high intensity harvest with burning reduced recruitment by 95% compared to controls. Seed production nearly doubled in burned treatments. In unburned prairie, recruitment is negligible, and harvest intensity does not have an effect on recruitment. For harvest-sensitive prairie species, a strategy incorporating moderate intensity seed harvest with burning is most likely to provide seed for large-scale restoration sustainably.