Assessing Relative Effectiveness of Physical and Sensory Deterrents to Protect Juvenile Trees From Damage by Fallow Deer

ABSTRACT Loss of trees in production landscapes has been widely documented and frequently attributed to both natural (climate) and human (e.g., introduced herbivores and land modifications) drivers. Effective interventions are required to restore landscapes and facilitate natural regeneration. Here, we used a natural experiment to test for the effectiveness of interventions designed to protect seedlings and saplings from herbivore damage and thus facilitate forest and woodland regeneration. We conducted a systematic survey of 283 young trees in a 47‐ha site within a Eucalyptus viminalis grassy woodland contained in a conservation reserve of a grazing property in Lutruwita, Tasmania. Interventions included physical barriers to protect young trees, including caging (78 young trees), erecting stock exclosures (44) around groups, and the novel use of wool offcuts (‘dags’), as a sensory deterrent, placed around the bases (41). All three interventions reduced browsing damage compared to controls. Browsing damage was predominantly attributed to Fallow deer ( Dama dama L.), based on the type of damage recorded and the relatively high proportion of deer scats across the study site. As a measure of effectiveness, young tree height was greater under any of the interventions than for unprotected trees (ranging from 27%–68% taller). Our results indicate that human intervention is required to increase the proportion of naturally regenerating trees reaching maturity, and that wool dags, as a by‐product of the grazing industry, can be an effective barrier to reduce damage from feral deer as a cheaper alternative to caging.