In Andean Patagonia, Argentina, severe wildfires produce high mortality in Austrocedrus chilensis forests. Owing to its high timber quality, A. chilensis trees are generally salvage logged right after wildfires. Post-logged areas result in open, denuded stands with low herbaceous or shrub cover, which precludes natural A. chilensis regeneration. In severely burned A. chilensis stands, we determined how different site conditions (salvage logging, SL, and without logging, WL), and the combination of different methods of control of above- and belowground competition and micro-environmental factors (incident radiation, soil temperature and soil moisture) affected survival, growth and hydric status of planted A seedlings. Two growing seasons after plantation, seedling survival was lower than 10% at SL sites, whereas it was near 90% at WL sites. Four seasons after establishment, and regardless of competition treatments, no seedlings survived at SL sites, whereas over 75% survived at WL sites. Radiation attenuation by canopy of WL sites benefitted A. chilensis seedling survival, and no additional control of early successional herbaceous species should be necessary to attain high seedling survival 4 years after restoration. Selective logging, by leaving ~50% of burned snags, and active restoration practices, may help reconcile economic needs of society and ecological requirements of A. chilensis for recovering former structure and functions.

Condiciones de suelo y vegetación en tres bosques quemados de Nothofagus pumilio en Argentina y experiencias para su restauración activa

The availability of soil-stored seed determines initial plant functional types in post-fire landscapes. We evaluated the post-fire regeneration of Nothofagus pumilio forests, in Patagonia, Argentina, analyzing the soil seed bank (SSB) and the above-ground vegetation (AV). At three sites: La Colisión, Río Turbio and Monte Zeballos, burned in 2008, 1980 and 1941, respectively, we sampled the SSB and AV in two transects from the edge of the remaining forest, up to 90 m within the burned area, and recorded the emergence (198 soil samples) and presence of vascular species. To determine the effect of the distance to the remnant forest on the germinable seed bank, we performed simple linear regression analysis through the use of linear mixed-effect models, and we analyzed the similarity between the composition of SSB and AV with PERMANOVA. The emergence of plant growth forms had different patterns in relation to the distance from the forest in the three sites, which might be associated with the time of fire occurrence, and specific characteristics of each site. The emergence of N. pumilio was registered at more than one distance at the recent burning site. Herbs constituted the main source of cover with 69% of the composition, and native/endemic species represented 71%. This study contributes to the understanding of the relationship between the seed bank and standing vegetation and a better understanding of the resilience of post-fire N. pumilio forests. Our findings suggest that from 15–20 m from the edge, the SSB would be insufficient to ensure the spontaneous recovery of the forest, making active restoration necessary in order to tend to a recovery of the structure and functionality of the original community.

Questions: In terms of biodiversity conservation, forest plantations are often considered problematic because they usually have negative effects on natural ecosystems. Soil seed banks could play an important role in restoring vegetation that was originally present, by recruiting species that have disappeared above‐ground. We addressed this topic in plantations located in the Patagonian steppe by asking the following questions: Are richness, abundance and composition of steppe above‐ground vegetation and soil seed bank affected by plantations? Is species composition of the above‐ground vegetation and soil seed bank similar in plantations and in the steppe?Location: NW of Chubut Province, Patagonia, Argentina.Methods: We selected three plantations located in the steppe, and delimited three sectors: steppe, plantation edge and plantation interior. We compared richness and abundance by species origin and growth form among sectors for the above‐ground vegetation and soil seed bank compartments, using generalized linear mixed models. We compared species composition for each compartment and between them using permutational multivariate analysis of variance and non‐metric multidimensional scaling.Results: In above‐ground vegetation, we found a decrease in richness and abundance, and changes in composition from the steppe to the plantation interior. Richness and abundance of the soil seed bank did not show differences among steppe and the plantation sectors, although composition was different among them. Above‐ground vegetation and soil seed bank species composition were always different; native perennial herbs and shrubs were predominant in the above‐ground vegetation while exotic annual herbs dominated the soil seed bank.Conclusions: Our findings suggest that plant recruitment from the soil seed bank would not be sufficient for restoring depleted species pools in the above‐ground vegetation of plantations. Therefore, actions promoting native species reestablishment and control of exotics should be considered to reach the aim of restoring biodiversity in former plantations.