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

Abstract

Direct sowing of acorns is a technique for oak forest restoration, however, high seed predation by mammals can occur and cost‐effective alternatives to protect acorns are therefore required. The present study evaluated the protection provided by chili peppers (Capsicum annuum and Capsicum pubescens) to acorns of Quercus germana, an endangered endemic oak tree of the cloud forests. Greenhouse and field experiments were established to evaluate the effect of chili peppers on acorn removal, germination, and seedling emergence. These processes were related to the prevalent microhabitat characteristics where the acorns were introduced, and the fauna that consumed chili peppers and acorns was identified using camera traps. In the greenhouse trial, more seedlings emerged from acorns covered by fruits of C. pubescens (65.71 ± 8.14) and C. annuum (57.14 ± 8.49%) compared to unprotected acorns (31.43 ± 7.96%). Contrary to expectation, acorn removal in the field was greater using C. pubescens than the unprotected acorns, particularly in microsites with lower tree cover and higher grass dominance. Acorn removal was similar to chili pepper treatments. These results are explained by the camera trap records, which showed bird species consuming Capsicum fruits, thus exposing the acorns to subsequent removal and/or consumption by rodents. The studied Capsicum fruits had no negative effect on acorn germination and seedling emergence under greenhouse conditions, and future practices could, therefore, involve the use of different techniques to prevent the discovery of chili peppers by birds; for example, using green chili peppers for camouflage, or hiding them under litter or herbaceous vegetation.