Management without consistency: How intermittent silvicultural practices drive plant invasions

• Consistency of silvicultural effort influences plant invasions in Shorea robusta forests. • Intermittent management facilitates the establishment and spread of invasive plants. • Forest management, its interaction with the resident vegetation cover, and proximity to roads are key drivers of plant invasions in forests. • Well-planned silvicultural interventions are crucial for preventing unintentional management outcomes and effectively controlling plant invasions in forest ecosystems. Silviculture plays a vital role in shaping forest structure and species composition, while also influencing the spread of invasive plant species in forest ecosystems. However, the role of local silvicultural practices on invasive plants' invasion dynamics is poorly understood in Shorea robusta forests. In the south-central Tarai region of Nepal, the forests are either intermittently managed (characterized by active but sporadic silvicultural interventions) or conventionally managed (limited to periodic removal of dead, dying, and deformed trees). This study examines the effects of these two forest management practices on invasive plant diversity and abundance in Shorea robusta -dominated forests. Sixty plots (20 m × 50 m), equally distributed in each of the management practices, were systematically sampled. In each plot, the occurrence of vascular plants, including invasive plant species, their cover, tree basal area, and tree canopy were measured, along with disturbance factors (e.g., logging, grazing, and fire). Species richness, diversity, and species composition were compared between the two management practices. The results indicated that both species richness and cover of invasive plants were significantly higher in the intermittently managed forest, where the canopy openings created to promote tree regeneration were frequently colonized by invasive plants. Intermittent forest management emerged as the most influential factor in determining the richness and cover of invasive plants in the forests. This study suggests that the absence of competition control activities after tree felling creates favorable conditions for the spread of invasive plant species. Regular silviculture interventions, including targeted control of invasive plants, are crucial to prevent plant invasions in the forests dominated by Shorea robusta in the south-central Tarai region of Nepal.