Dramatic long-term restoration of an oak woodland due to multiple, sustained management treatments

Abstract

We measured 34 years of plant community change in a degraded oak woodland undergoing ecological management. Management included regular prescribed fire, control of white-tailed deer populations, repeated sowing of a diverse seed mix, and removal of invasive plants. We tracked change with several conservation metrics. Time series analysis showed no significant changes over time in either plant species richness or the Shannon-Weiner diversity index. Floristic Quality Assessment measures—the Floristic Quality Index (FQI), Cover-weighted FQI, and the Mean Coefficient of Conservatism (Mean C )—all increased dramatically over time, such that their values now surpass those of the highest quality representative of this habitat in the region. Cover-weighted FQI had the added benefit of being quick to respond (negatively and positively) to short-term management changes during the study. This sensitivity highlights its utility for adaptive management, enabling timely, data-driven changes to ongoing management regimes. Plant community composition showed striking changes during the study period, as species of high conservation value replaced weedier species. As a group, conservative woodland species are notoriously slow to recover from degradation, making this flora’s recovery particularly notable. A mid-study cessation of management immediately stalled the woodland’s recovery according to Floristic Quality metrics, but the restoration quickly returned to its positive trajectory with the resumption of management treatments. These results illustrate that impressive plant biodiversity restoration can be achieved, even in highly degraded contemporary oak ecosystems, if ecological management is comprehensive and if it is sustained over time.

High‐diversity seed additions promote herb‐layer recovery during restoration of degraded oak woodland

“…Given the similarities in total native cover, but dramatic differences in dominance of functional groups between control (ruderal forbs) and sown (C 3 perennial grasses) locations, future studies should investigate whether reinvasion rates vary among these two plant communities. Our results are consistent with the prediction that degraded oak woodlands exhibit low recovery potential for matrix and conservative species without native seed addition (Glennemeier et al, 2020;Lamb et al, 2022;Packard, 1997). and Sanicula odorata (C = 2)) dominated forb cover in control transects.…”

“…Unlike most grassland species, many herbaceous species in woodlands (especially conservative forbs) produce low quantities of seed and are unavailable in commercial trade (Ladwig et al, 2020), which has likely limited the research and use of seed mixes in woodland restoration (Mottl et al, 2006). Consequently, it remains poorly known whether sowing species‐rich seed mixtures can promote the floristic recovery in degraded oak woodland (Brudvig et al, 2011; Glennemeier et al, 2020), and increase biotic resistance to non‐native invasion (Schuster et al, 2018). A few previous studies indicate that woodland seed additions may promote floristic recovery (Glennemeier et al, 2020) or reduce non‐native reinvasion (Wragg et al, 2021), although these studies did not examine establishment rates of sown species or compare changes in native plant community properties between sown and non‐sown locations at the same site.…”

“…Consequently, it remains poorly known whether sowing species‐rich seed mixtures can promote the floristic recovery in degraded oak woodland (Brudvig et al, 2011; Glennemeier et al, 2020), and increase biotic resistance to non‐native invasion (Schuster et al, 2018). A few previous studies indicate that woodland seed additions may promote floristic recovery (Glennemeier et al, 2020) or reduce non‐native reinvasion (Wragg et al, 2021), although these studies did not examine establishment rates of sown species or compare changes in native plant community properties between sown and non‐sown locations at the same site. The one previous study to do this found strong evidence for seed limitation (19/22 species) in the herb layer of an oak woodland; however, the species sown were specifically selected to have high germination and rapid growth to reproductive maturity (Brudvig et al, 2011).…”

Restoration Contributes to Maintain Ecosystem Services and Bio-Cultural Linkages Between Wetlands and Local Communities: a Case from a Botanical Diversity Hotspot in Japan

“…In the conifer-removal plots, the number of species appearing or disappearing was relatively high, and thus plant species composition may be changing over the short term. The rapid change in species composition after the treatment is typical in similar restoration projects (e.g., Glennemeier et al 2020 ), and this implies that long-term monitoring is necessary. We conclude that conifer removal on the biodiversity-rich seepage wetlands in the Circum-Ise Bay region can be a prioritized option for managers to conserve their unique plant composition, diversity, and cultural association with local people.…”

Twenty years of tallgrass prairie restoration in northern Illinois, USA

“…In a 20-year study of restored prairie in Kansas, differences in plant community diversity did not become apparent between restoration approaches altering soil heterogeneity until 16 years after planting (Baer et al, 2020). A longitudinal study of a single site in northeastern Illinois showed consistent plant diversity across 34 years, driven by decreases in non-native species and increases in native species (Glennemeier et al, 2020). Many restoration projects set up regular plant monitoring, but sampling is not always repeated consistently.…”