Wapiti browsing impact on Taxus cuspidata growth and regeneration in Northeast China Tiger and Leopard National Park

Abstract

Ungulate browsing affects plant communities directly and indirectly, altering ecological community structure and composition. Within the Northeast China Tiger and Leopard National Park, intensive browsing by wapiti (Cervus elaphus) on Taxus cuspidata has severely impacted their growth and regeneration. Both species are flagship species for biodiversity conservation, and constitute primary conservation targets of the national park. It is therefore critical to evaluate whether wapiti browsing facilitates or constrains Taxus cuspidata population recovery. We conducted field investigations from 2020 to 2025 using quadrat surveys, plot monitoring, sapling assessments, and fence establishment. Data were analyzed with resource selection functions (RSF), generalized additive models (GAM), and piecewise regression to assess how wapiti browsing affects the growth and regeneration of Taxus cuspidata populations. Our findings indicate that: (1) Browsing probability decreases with increasing distance from mature trees (>15.7 m) and further declines beyond 29.3 m, promoting population distribution range and self-thinning. (2) At the individual level, Wapiti browsing may hinder growth. Browsed saplings exhibited adaptive shifts in resource allocation, prioritizing lateral branch regeneration and basal diameter recovery over apical dominance; (3) Low-intensity browsing (1–30 %) enhances Taxus cuspidata regeneration. (4) To balance conservation, fence saplings within 15.7–29.3 m of mature trees based on the browsing threshold. These results challenge conventional paradigms of browsing impacts by demonstrating context-dependent facilitation effects. We propose a spatially explicit conservation framework integrating browse-tolerant regeneration zones with targeted sapling protection, advancing sustainable co-management of ungulates and endangered flora in boreal ecosystems. This addresses management challenges in national park and contributes to research on herbivore-plant interactions and co-evolution.