Annual Understory Plant Recovery Dynamics in a Temperate Woodland Mosaic during a Decade of Ecological Restoration

Abstract

Temperate woodlands are one of the world's ecosystems in greatest need of ecological restoration, but relatively little is known about their floristic recovery dynamics over decadal timescales. From 2000 to 2012, we monitored understory plant communities in a woodland mosaic in Missouri, USA, as it underwent restoration via prescribed, dormant-season burning and mechanical thinning of red cedar (Juniperus virginiana) and exotic shrubs. Native species richness increased linearly by 36% over this time period, driven primarily by an influx of forb species in thin-soiled upland areas where red cedar was removed. Floristic quality also increased with differential dynamics across local communities; forest floristic quality saturated quickly whereas floristic quality increased gradually over the time series in woodlands and red cedar–dominated woodlands. Species that underlay these patterns were mainly ruderal or matrix forbs and grasses with little dependence on intact, undisturbed habitats. In contrast, conservative species were rare or absent. This case study suggests that understory plant recovery dynamics may be slower in harsher and more degraded sites and faster in more mesic sites within a woodland mosaic. Our observations set a benchmark for woodland understory plant recovery dynamics and indicate that a future restoration challenge is to prioritize the managed translocation of dispersal-limited, conservative species.