According to the global latitudinal diversity gradient, a decrease in animal and plant species richness exists from the tropics towards higher latitudes. The aim of this study was to describe the latitudinal distribution patterns of Chilean continental flora and delineate biogeographic regions along a 4270-km north-south gradient. We reviewed plant lists for each of the 39 parallels of continental Chile to build a database of the geographical distribution of vascular plant species comprising 184 families, 957 genera and 3787 species, which corresponded to 100%, 94.9% and 74.2% of the richness previously defined for Chile, respectively. Using this latitudinal presence-absence species matrix, we identified areas with high plant richness and endemism and performed a Cluster analysis using Jaccard index to delineate biogeographic regions. This study found that richness at family, genus and species levels follow a unimodal 4270-km latitudinal distribution curve, with a concentration of richness in central Chile (31-42°S). The 37th parallel south (central Chile) presented the highest richness for all taxonomic levels and in specific zones the endemism (22-37°S) was especially high.This unimodal pattern contrasts the global latitudinal diversity gradient shown by other studies in the Northern hemisphere. Seven floristic regions were identified in this latitudinal gradient: tropical (18-22°S), north Mediterranean (23-28°S), central Mediterranean (29-32°S), south Mediterranean (33-37°S), north temperate (38-42°S), south temperate (43-52°S) and Austral (53-56°S). This regionalization coincides with previous bioclimatic classifications and illustrates the high heterogeneity of the biodiversity in Chile and the need for a reconsideration of governmental conservation strategies to protect this diversity throughout Chile.

International agreements combined with the recent Chilean Forestry Policy (2015-2035) represent a challenge and an opportunity for forest landscape restoration in Chile. Nevertheless, restoring over 500,000 ha using mainly native species seems like a daunting task by 2035. Here, we discuss the three major bottlenecks that currently constrain the restoration efforts of forest ecosystems in Chile. First, Chile urgently needs a national strategic plan for forest landscape restoration, which should take into account mid-and long-term goals. There is also a need to prioritize resource allocation for efficient use, promoting the creation of economic subsidies for restoration that consider different types of forest ecosystems. Second, there is a great need for better nursery protocols in plant production as well as to strengthen educational programs for professional and technical training, given the lack of high-quality personnel in Chilean nurseries. This would help increase the currently limited national plant supply, improving quality and increasing the diversity of native species suitable for forest restoration. Lastly, taking advantage of novel eco-technological tools and promoting innovative plantation design would help to overcome the usually deficient results in the establishment phase, leading to higher survival rates and promoting better performance of native species. Beyond current experiments that are relatively efficient on a small spatial scale, the practice of forest restoration needs to become massive and successful at a landscape scale. More and better applied research is crucial for improving the impact of forest landscape restoration, so that Chile can achieve its forest restoration challenge in the next decade.

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Abstract:Recent studies have shown that, owing to a lack of seed trees, the natural rate of recovery of fire-disturbed bog forests previously dominated by the endemic and endangered conifer Pilgerodendron uviferum (D. Don) Florin is extremely slow. Hence, increasing the number of seed trees in the landscape through restoration planting could remove the principal biotic filter, limiting recovery of these forests. Here, we analyzed how the success of restoration plantings may be improved through the choice or manipulation of microsites in P. uviferum forests on Chiloé Island in North Patagonia. For this purpose, we manipulated microtopography in water-logged sites in bogs (mounds, flat terrain, mineral soil) and changed canopy conditions (gaps, semi-open, closed canopy) in upland sites with better drainage. In bogs, there was no significant effect of microtopography on growth and survival of P. uviferum plantings. However, fluorescence measurements indicated lower stress in seedlings established on mounds. Seedlings in upland areas established beneath a nurse canopy had lower mortality and higher relative shoot growth, foliar nutrients, photosynthetic light use efficiency and chlorophyll fluorescence values than those planted in the open. This indicates that seedlings of the slow growing P. uviferum can tolerate extremely wet conditions, yet suffer from stress when grown in the open. Here, the OPEN ACCESSForests 2013, 4 86 removal of canopy appeared to have also removed or reduced mycorrhizal networks for seedlings, leading to poorer nutrition and growth. Based on these results, recommendations for restoration plantings in highly degraded P. uviferum forests are presented.

Currently, Pilgerodendron uviferum forests cover over 172,000 hectares of Chiloé Province. The traditional utilization of these forests caused the destruction and burnt of extensive areas of cypress. Therefore this species was classified by IUCN as vulnerable and included in Appendix I of CITES. This study aimed to analyze and characterize the dynamics of P. uviferum forests in the coastal range of Chiloé, specifically in four sites (one pristine and three disturbed) located near Lake Tepuhueico in the center-south of Chiloé Island. A floristic composition evaluation and quantitative, diametric and age structure analyses for each sector were conducted. Furthermore, the original stand structure of the burnt Pilgerodendron forests, existing before the fire, was reconstructed. The fire that occurred in the study area produced big changes in the habitat, exceeding the persistence threshold of P. uviferum. The disturbed zone was considerably damaged on its structure, showing substantial reductions of basal area (over 90%) and density (over 87%) for the species. This event allowed the establishment and dominance of young second-growth mixed stands of Nothofagus nitida, Drimys winteri and Tepualia stipularis which, in undisturbed sites, belong to a different succesional sequence. However, there are small pristine stands of P. uviferum that must be preserved because of their structural complexity and their importance as seed suppliers for disturbed neighboring areas.