Direct seeding success of four threatened oak species in a peri-urban forest: effects of microhabitat and rodent exclusion

Spicing up oak forest restoration: a preliminary report of the protective use of chili peppers in direct seeding of acorns

“…Our results show that acorns introduced into Capsicum fruits germinated at the same rate as uncovered acorns under both greenhouse and field conditions. The germination speed of acorns has also been related to acorn predation probability since faster germination and seedling emergence allow a greater proportion of acorns to escape predation by reducing the time of exposure to predators, such as mice (Mechergui et al 2023;García-Hern andez & L opez-Barrera 2024). Oak species with acorns that germinate immediately upon seed fall (white oaks such as Quercus germana) are detected by squirrels due to their odor, and the embryos are removed before the seeds are cached.…”

“…Alternative trials in replicate degraded areas may consider introducing the Capsicum fruits under a litter layer in the open areas or in microhabitats with higher vegetation cover (shrubs or isolated trees), using other Capsicum species with green fruits but a high pungency level, without affecting seedling establishment. It also should be considered that rodents prefer to forage for acorns in low-risk patches such as under and near shelterwoods, shrubs, slash piles, and so forth (Leverkus et al 2013;Löf et al 2019;García-Hern andez & L opez-Barrera 2024). The trade-off between reducing the detection of the chilies by birds versus increasing rodent activity should, therefore, be evaluated.…”

“…Different aspects must be considered when scaling up use, including the total cost and transportation logistics, number of acorns per device, use of biodegradable and sustainable materials, and time required for implementation. Furthermore, the effectiveness of each technique depends on the acorn characteristics, specific assemblage of predators, and climatic and microhabitat complexity of natural or modified systems (Leverkus et al 2015;Löf et al 2019;García-Hern andez & L opez-Barrera 2024).…”

“…In many ecosystems, acorns placed in humid substrates can germinate. Seedlings emerge even in the absence of light, but in open areas subject to variations in soil and air humidity, a lack or excess of humidity may also be detrimental to acorns exposed either to desiccation or to fungal attacks and decomposition (Mechergui et al 2023;García-Hern andez & L opez-Barrera 2024;Liu et al 2024).…”