Successional Dynamics Are Influenced by Cattle and Selective Logging in Nothofagus Deciduous Forests of Western Patagonia

Cattle grazing and selective logging alter the functioning of an ecosystem, but their impacts on forest regeneration, particularly in relation to forest successional stages, are yet poorly understood. This study examined how these activities affect the regeneration of Nothofagus antarctica (& ntilde;ire or & ntilde;irre) and N. pumilio (lenga) pure forests in Patagonia and whether these effects vary between old-growth and secondary forests. We assessed seedlings by origin (sexual, asexual) and height classes (<0.3 m, 0.3-0.6 m, >0.6 m) across 88 plots (25 x 20 m). Selective logging intensity was measured via the basal area of tree stumps, and cattle grazing pressure via dung counts. Forest regeneration, as predicted by human disturbances, forest successional stage, and tree density (parent trees), was modeled using generalized linear models. For N. antarctica, regeneration was exclusively asexual and showed a positive influence for selective logging and cattle, but negative with both interacting. In contrast, the most recent regeneration (R1) was predominantly influenced by the density of parent trees and successional stage. Conversely, N. pumilio regeneration, entirely sexual, was unaffected by cattle grazing, relying instead on parent tree density, logging intensity, and successional stage. These findings highlight the species-specific dynamics of regeneration under anthropogenic pressures. Understanding the interactions between natural and human disturbances is critical for conserving Nothofagus forests. Our results provide a basis for targeted restoration efforts and policies to mitigate degradation and promote ecosystem resilience.