Effects of forest management on vascular plant diversity of mixed temperate Nothofagus forests along a precipitation gradient

Abstract

Under adaptive management, operational adjustments from planning to monitoring aim to promote plant diversityand enhance forest resilience. We evaluated the long-term effects (> 25 years) of shelterwood harvestingon the taxonomic and functional diversity of vascular plants in Nothofagus dombeyi, N. obliqua and N. alpina(Nothofagaceae) forests of north-western Patagonia. The study was conducted in three sites (West, Middle, andEast) located along a west-east precipitation gradient. Changes in plant diversity between managed (m) andunmanaged (u) forest were assessed using linear models, multivariate analyses and network approaches. Werecorded 63 plant species, 34 of which were endemic to Patagonia. Chusquea culeou (Poaceae) and Nothofagusregeneration (diameter at breast height < 10 cm) were dominant, except in the East managed forest. Life formand management were associated per site. Managed forests showed higher Dq= 2 alpha diversity, while betadiversity was affected by site and management. Unmanaged forests in the West and Middle sites had similarcompositions, while the East unmanaged forest had a high number of unique species. In the managed West andMiddle sites, silviculture increased spatial heterogeneity and promoted Nothofagus regeneration. In contrast, themanaged East site displayed more homogenous microsites with higher Poaceae frequency and bare soil coverage.These findings highlight the complex role of silviculture in shaping plant communities under varying environmentalconditions, emphasizing the importance of long-term studies across environmental gradients to guideadaptive forest management.