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A structural and compositional definition of old-growth forest is presented, which places emphasis on the lack of recurrent human impact, the presence of a shade-tolerant canopy with emergent pioneers, and a patch area that minimises edge effects. Using this definition, we provide an overview of the current conservation status, relevance of plant-animal interactions, and unique features of nutrient fluxes in old-growth forests of southern South America. Chile hosts the largest area and latitudinal extent of old-growth temperate forest remaining in the southern hemisphere, reaching 56° S in the Cape Horn Archipelago. Despite recent public and private efforts to protect remaining old-growth forests and their endemic biodiversity, they continue to decline steeply as a result of new routes of access to commercial stands, lack of protection of coastal areas, anthropogenic fire, and expansion of monoculture-based forestry toward higher latitudes and altitudes. Pollinators (insects and birds) and vertebrate frugivores (birds and an arboreal marsupial) are important mutualists of many Chilean rain forest trees, vines and epiphytes. There is evidence to suggest that some native pollinators and animal seed vectors may be highly susceptible to changes in forest structure due to loss of old-growth forest cover. Forest fragmentation and loss of keystone, animal-pollinated emergent trees due to logging and fires, have radically changed pollinator assemblages in rural landscapes, leading to reproductive dependence on European honey bees and other exotic species. Regarding other ecosystem functions, nutrient cycles in unpolluted old-growth forests of southern Chile are characterised by strong inorganic nitrogen (N) retention and large organic N leakage to forest streams. Non-symbiotic N fixation in litter and soil tends to increase in older stands. Knowledge of these "unpolluted nutrient cycles", particularly N and P, is still meager despite its relevance to understanding the conse

This chapter presents results of a scenario-building exercise, designed to explore future trends in forest biodiversity in four forest areas, and the potential implications for policy development and implementation. An expert consultation conducted in a workshop environment identified 11 principal pressures responsible for biodiversity loss in Latin America, namely land-cover change, fire, invasive species, browsing animals, pollution, mining, development of infrastructure (roads, pipelines, dams), logging/fuelwood extraction, habitat fragmentation, climate change and loss of keystone species and ecological structures. The relative importance of these different pressures was assessed in each of four study areas, namely Central Veracruz (Mexico), the Highlands of Chiapas (Mexico), Rio Maule-Cobquecura (Region VII, Chile) and Los Muermos-Ancud (Region X, Chile). Scores were generated for each area describing both variation in intensity of the pressures over time and their potential impacts on different components of biodiversity. The scoring process was used to support development of three scenario narratives for each area, namely business as usual, deepening conservation crisis and effective conservation. Recommendations for policy development and implementation are presented for each study area, based on these scenarios. The results indicate that action on global commitments to reduce biodiversity loss must take account of the geographical variation in the relative importance of different pressures and their varying impacts on different biodiversity components. Policy developments and practical conservation action will need to be tailored for individual areas, defined at the sub-national level.