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Author: Admin | 2025-04-28
Al., 2020).However, we observed improvements in some soil characteristics over time (% sand and nutrients) (Supplementary Table 1), although the soil quality remained below that of reference forests. Despite the severe impacts on soil conditions, the complexity of the vegetation increased slightly with the abandonment age. The surrounding old-growth forests can probably function as a continuous source of seeds and contribute to increasing diversity over time (Fujisaka et al., 2000; Rodrigues et al., 2004).Forest Composition in Abandoned Gold Mining AreasPlant composition in almost all abandoned plots and plant size classes show that the dominant species are the fast-growing O. pyramidale and C. engleriana. Similarly, abandoned fallows in central-eastern Peru are dominated by T. micrantha and Cecropia membranacea (Fujisaka et al., 2000). In many other degraded lands across the Amazon basin, the presence of Cecropia spp. is common in natural regeneration but O. pyramidale (Mesquita, 2000; Mesquita et al., 2001; Rodrigues et al., 2004; Kalamandeen et al., 2020) is not, even though O. pyramidale is naturally distributed in these areas (ITTO, 2019).The composition of the surrounding forests plays an important factor in driving the floristic composition of the plots. O. pyramidale and Cecropia spp. are abundant in riverbanks in the Madre de Dios region, and G. crinita, S. parahyba, and Calycophyllum spruceanum are common species in secondary forests and even in primary forests of this region (Gentry, 1982; Phillips and Gentry, 1993; Reynel et al., 2003; Dueñas and Garate, 2018).Implications to Forest RestorationThe slow pace of natural regeneration observed after 19 years of mining abandonment suggests the need for active restoration strategies with soil reclamation efforts to accelerate forest recovery. The combination of strategies can assist the restocking of transitional succession species speeding up the succession process (Evans et al., 2013; Román-Dañobeytia et al., 2015; Orozco-Aceves et al., 2017).In the southeastern Peruvian Amazon, however, considering that active restoration with soil reclamation costs 2,100–3,500 US$ ha–1 during the first year of activity (Román-Dañobeytia et al., 2015) and that the areas degraded by gold mining sum up to 80,000 ha, only during 2007–2017 (Caballero Espejo et al., 2018), this strategy imposes financial challenges. Therefore, it is necessary to evaluate the relative effectiveness of different restoration strategies, ranging from passive (e.g., natural regeneration) to more intensive ones (e.g., mixed plantations of native species with soil reclamation). In older sites, natural regeneration followed by enrichment with late-successional species could further accelerate the successional process.Despite not formally testing the tolerance of specific species to soil conditions, we observed that several tree taxa were found continuously at high densities despite the extensive soil disturbance. O. pyramidale and C. engleriana colonized and dominated areas 19 years after abandonment, which could have created a favorable structure for the establishment
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