Herbivory and flooding impacts on planted bottomland hardwood seedlings

Abstract

Bottomland hardwoods forests (BLHW) are increasingly subject to active management for water quality improvement, streambank stabilization, to mitigate for urban expansion and to improve habitat for wildlife. Since the majority of remaining BLHW are degraded, restoration attempts are becoming commonplace within the Western Gulf Coastal Plain (WGCP) of the US. However, restoration success in terms of obtaining high stem densities of desirable species has been mixed, with managers observing survival rates <15 per cent for planted oak and hickory seedlings in some situations due to a variety of limitations. Over two growing seasons, we investigated the effectiveness of portable electric fences, individual tree shelters and 2.4-m woven wire high fences for mitigating herbivory by white-tailed deer (Odocoileus virginianus) and feral swine (Sus scrofa). Treatments fell within degraded forested areas and abandoned agricultural fields where we tested four species of interest: Nuttall oak (Quercus texana Buckley), Shumard oak (Q. shumardii Buckley), bur oak (Q. macrocarpa Michx.) and pecan (Carya illinoinensis K. Koch). Where herbivory occurred, mitigation techniques produced a higher survival rate ($\bar{\rm{X}} $ = 17.6 per cent) than unprotected areas ($\bar{\rm{X}} $ = 9.1 per cent). In areas of high white-tailed deer density, prominent browsing was evident, resulting in two-growing-season height growth of seedlings being less in non-fenced ($\bar{\rm{X}} $ = 2.33 cm) and electric ($\bar{\rm{X}} $ = 4.33 cm) fenced plots compared with high fences ($\bar{\rm{X}} $ = 13.02 cm) and individual tree shelters ($\bar{\rm{X}} $ = 24.23 cm). Additionally, we observed a negative relationship between survival and the number of days seedlings that were inundated with flood waters during the growing season. Matching species of interest to the site conditions, specifically the local hydrologic regimes, should carry a high priority in planning a restoration project within BLHW in the WGCP.

Different Phenotypic, Photosynthetic, and Physiological Responses to Flooding between Q. nuttallii and Q. palustris

“…showed two distinct phases of flood response, during which physiological changes in seedlings predominated for the first three days, and substantial morphological and anatomical shifts also occurred during this period [ 16 , 21 ]. Previous studies reported that Q. nuttallii and Q. palustris showed resistance to waterlogging, which is desirable from both wildlife and timber production perspectives [ 22 , 23 , 24 ]. However, whether the two different oak species’ physiological response patterns and flood resistance are uniform remains unclear.…”

Automated precise seeding with drones and artificial intelligence: a workflow

“…A common, widespread factor is herbivory by large mammals. This is one of the most important reasons for failure in the success of reforestation programs (Castro et al 2021; Jacques et al 2022). Provision of protection against herbivores at least until the plants are tall enough to escape the loss of the apical buds could enhance restoration success.…”