Riparian zones are ecosystems dependent on courses or water bodies with a variable array of vegetation immersed in watersheds. These areas perform essential functions to the preservation of ecosystems and their spatial relations, influencing species richness and natural beauty, while providing goods and services for biodiversity and human welfare. Therefore, in any territorial unit, it is necessary to place the quality and relevance of riparian systems into context, given their importance as economic resources and providers of ecosystem services. However, the evaluation of the conservation status of these systems implies collecting those aspects that allow carrying out activities under current environmental regulations, guarantying the safekeeping of these systems in the long term. This paper explores the relevance of riparian zones in general and their participation in current Chilean legislation, with the aim of providing further information on their restoration and conservation. Chilean legislation identifies riparian zones as associated with ecosystem protection, but some weaknesses have been identified regarding the incorporation of the concept of restoration and the lack of financial incentives to carry out better protection. National Government should consider as a goal to create or adapt norms that allow protection as well as restoration of riparian systems, which would provide long-term viability to these ecosystems and their functions.

Quillay (Quillaja saponaria Molina) and peumo (Cryptocarya alba [Molina] Looser) are two tree species endemic to Chile that grow in Mediterranean climate zones, characterized by a summer season with high temperatures, high solar radiation, and low soil water availability. A study was conducted with 2-year-old Q. saponaria and C. alba plants and two substrate water conditions: well-watered and controlled water restriction. At the end of the study, anatomical leaf modifications were analyzed. The tissues were anatomically described in transverse sections of juvenile and adult leaves, measuring leaf thickness, cuticle thickness, and cell density of the mesophyll parenchymal tissues. In the young leaves of Q. saponaria plants undergoing water restriction treatment, an increase in cuticle and leaf thickness and a decrease in the density of the palisade and spongy parenchyma were observed. In contrast, a significant reduction in leaf thickness was observed in adult leaves of both species with water restriction treatment. The anatomical changes in the leaves of Q. saponaria and C. alba suggest an adaptation to adverse environmental conditions, such as water restriction.

The ecosystems of the Mediterranean regions are severely threatened by human activity, and although we have made progress in physical restoration measures, little is known about the interactions between the plants of these biomes. The objective of this study is to contribute to document interactions between seeds and seedlings of three woody species native to Chile (P. chilensis, Q. saponaria and A. caven), which could be used for restoration actions (e.g., after forest fires). In a first experiment, we evaluated the germination response, the initial elongation and the interactions between the seedlings that germinate exposed to the chemical compounds of the other species. In a second experiment, we compared the survival and growth of seedlings in monospecific versus bispecific mixtures, using a substrate similar to that which is present after a wildfire. Seed extracts of teguments promoted germination of P. chilensis, but cotyledons and whole seed extracts inhibited germination of only one species, Q. saponaria, with very high intensity. The effects of the extracts on initial seedling elongation were more variable, including five inhibitions and one facilitation. Negative effects on germination and elongation included two cases of autotoxicity. The survival of seedlings grown in mixtures showed only two differences between monospecific and bispecific mixtures, both positive, constituting a reciprocal effect between two species. Only in one case was there a significant difference in seedling growth, which was root growth inhibition. Indeed, these results reveal an interaction between species, the type and intensity of which varies according to the condition of the seed or seedling. The negative effect found in seedling root growth reflects an allelopathic interaction that conditions a vital aspect for the establishment of these species, so this information is an opportunity to improve the establishment conditions in future reforestation projects, by avoiding particular species or promoting their proportion in plantation mixtures, either by planting or direct seeding.

Introduction: Forestry in many parts of the world depends on exotic species, making this industry a source of invasions in some countries. Among others, plantations of the genus Pinus, Eucalyptus, Acacia, Populus, and Pseudotsuga underpin the forestry industry and are a vital component of many countries economies. Among woody plants, the cosmopolitan genus Acacia includes some of the most commonly planted trees worldwide. In order to prevent, manage and control invasive plant species, one of the most used tools is species distribution models. The output of these models can also be used to obtain information about population characteristics, such as spatial abundance patterns or species performance. Although ecological theory suggests a direct link between fitness and suitability, this link is often absent. The reasons behind the lack of this relationship are multiple. Chile is one of the countries where Acacia species, in particular, A. dealbata and A. melanoxylon, have become invaders. Methods: Here, we used climatic and edaphic variables to predict thepotentially suitable habitats for A. dealbata and A. melanoxylon in continental Chile and evaluate if the suitability indices obtained from these models are associated with the observed performance of the trees along the country. Results: Our models show that variable importance showed significant similarities between the variables that characterize each species’ niche. However, despite the high accuracy of our models, we did not observe an association between suitability and tree growth.Discussion: This disconnection between suitability and performance can result from multiple causes, from structural limitations, like the lack of biotic interactions in the models, to methodological issues, like the usefulness of the performance metric used. Whatever the scenario, our results suggest that plans to control invasive species should be cautious in assuming this relationship in their design and consider other indicators such as species establishment success.