Different facets of tree sapling diversity influence browsing intensity by deer dependent on spatial scale

Area of Science:

• Ecology
• Forestry
• Wildlife Biology

Background:

• Deer browsing significantly hinders forest regeneration in mixed forests across Europe and North America.
• While tree species susceptibility to browsing varies, the influence of diversity facets (richness, identity, composition) on browsing intensity across spatial scales remains poorly understood.

Purpose of the Study:

• To investigate how species richness, identity, and composition affect deer browsing intensity at both regional and patch scales.
• To model browsing probability at the patch level and species-specific browsing proportion within patches.

Main Methods:

• Utilized forest inventory data from Hainich National Park, a mixed deciduous forest in Germany.
• Applied a hierarchical modeling approach to analyze browsing probability of patches (regional scale) and species-specific browsing proportions within patches (patch scale).

Main Results:

• At the regional scale, browsing probability increased with specific species composition (low European beech, high European ash).
• At the patch scale, species identity primarily determined browsing proportion, revealing a distinct preference ranking for 11 tree species.
• Species-rich patches were more likely to be browsed regionally but showed lower per-species browsing intensity at the patch scale; open canopies increased browsing intensity at both scales.

Conclusions:

• Deer browsing intensity is influenced by multiple diversity facets and environmental factors across different spatial scales.
• Findings advance the understanding of mammalian herbivore-plant interactions and highlight the importance of diversity in predicting and managing forest regeneration dynamics.
• Identifies specific regeneration patches and tree species most and least prone to browsing.