Woody species diversity in temperate Andean forests: the need for new conservation strategies

Chile has more than half of the temperate forests in the southern hemisphere. These have been included among the most threatened eco-regions in the world, because of the high degree of endemism and presence of monotypic genera. In this study, we develop empirical models to investigate present and future spatial patterns of woody species richness in temperate forests in south-central Chile. Our aims are both to increase understanding of species richness patterns in such forests and to develop recommendations for forest conservation strategies. Our data were obtained at multiple spatial scales, including field sampling, climate, elevation and topography data, and land-cover and spectrally derived variables from satellite sensor imagery. Climatic and land-cover variables most effectively accounted for tree species richness variability, while only weak relationships were found between explanatory variables and shrub species richness. The best models were used to obtain prediction maps of tree species richness for 2050, using data from the Hadley Centre's HadCM3 model. Current protected areas are located far from the areas of highest tree conservation value and our models suggest this trend will continue. We therefore suggest that current conservation strategies are insufficient, a trend likely to be repeated across many other areas. We propose the current network of protected areas should be increased, prioritizing sites of both current and future importance to increase the effectiveness of the national protected areas system. In this way, target sites for conservation can also be chosen to bring other benefits, such as improved water supply to populated areas.Universidad de ChileMinisterio de Planificación y Política Económic

Landscape restoration in a mixed agricultural-forest catchment: planning a buffer strip and hedgerow network in a Chilean biodiversity hotspot

Guidance for large-scale restoration of natural or semi-natural linear vegetation elements that takes into account the need to maintain human livelihoods such as farming is often lacking. Focusing on a Chilean biodiversity hotspot, we assessed the landscape in terms of existing woody vegetation elements and proposed a buffer strip and hedgerow network. We used spatial analysis based on Google Earth imagery and QGIS, field surveys, seven guidelines linked to prioritization criteria and seedling availability in the region’s nurseries, and estimated the budget for implementing the proposed network. The target landscapes require restoring 0.89 ha km−2 of woody buffer strips to meet Chilean law; 1.4 ha km−2 of new hedgerows is also proposed. The cost of restoration in this landscape is estimated in ca. USD 6900 per planted ha of buffer strips and hedgerows. Financial incentives, education, and professional training of farmers are identified as key issues to implement the suggested restoration actions

Mapping alien and native forest dynamics in Chile using Earth observation time series analysis

Chile is a global biodiversity hotspot and hosts a large proportion of the southern hemisphere’s temperate forests. The Chilean Valdivian temperate forest is a vulnerable ecosystem containing a highly ecologically valuable species assemblage. Productive forest plantations have involved deforestation of, and alien species introduction into, this ecosystem. This process has already severely impacted the western part of Chile (the Coastal Range) and is now occurring in the eastern part (the Andes), with forestry plantations promoted by government subsidies between 1974 and 2012. Archive Landsat satellite imagery classification and Google Earth Engine are used to assess land cover change over a 31-year period with a focus on alien species (Pinaceae and Eucalyptus spp.) spread and native (Nothofagus spp. and Araucaria araucana) deforestation. Results show a clear land cover pattern based on elevation: a higher altitude, relatively undisturbed area dominated by native forest (the Andes), and a lower altitude area where most human activity and related land covers are located (the valley area). The valley is highly dynamic because of constant land cover change due to forestry. Overall, Araucaria araucana cover has decreased over the study period, while Nothofagus spp. has remained relatively stable. Alien Pinaceae has decreased, while Eucalyptus spp. has remained stable. However, the results indicate that change analysis over long periods conceal dynamism. For example, Eucalyptus spp. sharply decreased between the 1980s and the 1990s and surged afterwards. Also, even though Nothofagus spp. cover dominates throughout the study period, change analysis shows a high degree of change in the valley area, indicating newly established Nothofagus spp. patches. Over the study period, long rotation Pinaceae plantations for timber have given way to shorter rotation forestry (alien Eucalyptus spp., native Nothofagus spp.) for pulp and local uses resulting from discontinuation of forest subsidies. In the absence of subsidies, only large-scale plantations can engage in long rotation forestry, as smallholders need the more stable income provided by shorter rotation forestry. Although higher elevations (the Andes) are dominated by native forest, several abandoned alien forest plantations may be the source of biological invasion. In addition, native forest degradation as a result of Araucaria araucana loss and shrub encroachment is occurring. Earth observation methods are key for forest and alien species monitoring and landscape management. They can enhance traditional, ground-based forest surveys and provide continuous and even retrospective monitoring of forest change thanks to the wide availability of current and historical satellite data

Regeneración natural y patrones de distribución espacial de la palma chilena Jubaea chilensis (Molina) Baillon en los bosques mediterráneos de Chile central

Jubaea chilensis is an endemic tree of Central Chile (31º15’- 35º22’ S). The current main conservation threats for this species should be associated with different factors which limit its natural regeneration, in particular the intense seeds crop. The analysis of spatial distribution patterns can be an important tool to understand the forest dynamic and the individual interactions. In this study was studied the spatial pattern of species recruitment and identifying the proper conditions for its regeneration. We predicted a clear spatial clumped pattern between regeneration individuals for all distance range studied, and also a clumped distribution associated to adult individuals. Spatial modeling showed that natural regeneration of J. chilensis is significantly related to higher vegetation cover, and especially in those with higher solar radiation. The results suggest that clumped regeneration of J. chilensis could be explained by the associated environmental conditions promoting the establishment of new seedlings, its seed dispersal mechanism, predation avoid, herbivory, and seeds crop. We also found a nurse effect which facilitates the natural regeneration of this species.Jubaea chilensis es un árbol endémico de la zona central de Chile (31º15’- 35º22’ S). Las principales amenazas actuales a su conservación estarían asociadas a diferentes limitantes a su regeneración natural, en especial la intensa cosecha de sus semillas. El análisis de patrones espaciales de distribución puede ser una importante herramienta para entender la dinámica de los bosques y la interacción entre los individuos. En este trabajo se estudió el patrón espacial de reclutamiento de la especie y se identificaron las condiciones favorables para su regeneración. Se estimó una notoria agrupación espacial entre los individuos de regeneración para todos los rangos de distancia analizados, y a su vez una distribución dependiente de los individuos adultos, agrupándose mayormente cercano a ellos. Por otra parte, la modelación espacial reveló que la regeneración natural de J. chilensis se relaciona significativamente con sitios de mayor cobertura vegetacional, y especialmente en sitios con una mayor radiación solar. Los resultados sugieren que la regeneración agrupada de J. chilensis se debería a la asociación de condiciones ambientales propicias para el establecimiento de nuevos individuos, su mecanismo de dispersión de semillas y escape de la depredación, herbivoría y cosecha de sus semillas, lo que estaría determinando la estructura espacial de la población. A su vez, los resultados confirman un efecto nodriza, facilitador de la regeneración natural de la especie

Natural forests loss and tree plantations: large-scale tree cover loss differentiation in a threatened biodiversity hotspot

Distinguishing between natural forests from exotic tree plantations is essential to get an accurate picture of the world's state of forests. Most exotic tree plantations support lower levels of biodiversity and have less potential for ecosystem services supply than natural forests, and differencing them is still a challenge using standard tools. We use a novel approach in south-central of Chile to differentiate tree cover dynamics among natural forests and exotic tree plantations. Chile has one of the world's most competitive forestry industry and the region is a global biodiversity hotspot. Our collaborative visual interpretation method combined a global database of tree cover change, remote sensing from high-resolution satellite images and expert knowledge. By distinguishing exotic tree plantation and natural forest loss, we fit spatially explicit models to estimate tree-cover loss across 40 millions of ha between 2000 and 2016. We were able to distinguish natural forests from exotic tree plantations with an overall accuracy of 99% and predicted forest loss. Total tree cover loss was continuous over time, and the disaggregation revealed that 1 549 909 ha of tree plantations were lost (mean = 96 869 ha year(-1)), while 206 142 ha corresponded to natural forest loss (mean = 12 884 ha year(-1)). Mostly of tree plantations lost returned to be plantation (51%). Natural forests were converted mainly (75%) to transitional land covers (e.g. shrubland, bare land, grassland), and an important proportion of these may finish as tree plantation. This replacement may undermine objectives of increasedcarbon storage and biodiversity. Tree planting as a solution has gained increased attention in recen years with ambitious commitments to mitigate the effects of climate change. However, negative outcomes for the environment could result if strategies incentivize the replacement of natural forests into other land covers. Initiatives to reduce carbon emissions should encourage differentiating natural forests from exotic tree plantations and pay more attention on protecting and managing sustainably the former

Efecto de la fragmentación forestal sobre la estructura vegetacional de las poblaciones amenazadas de Legrandia concinna (Myrtaceae) del centro-sur de Chile Effect of forest fragmentation on vegetation structure of Legrandia concinna (Myrtaceae) threatened populations in south-central Chile

La fragmentación del hábitat es una de las principales amenazas para la integridad de los ecosistemas. En este estudio se evaluó el efecto de la fragmentación sobre la estructura de la vegetación en poblaciones de la especie arbórea Legrandia concinna en el centro-sur de Chile. Se describió el patrón de ocupación de las poblaciones de Legrandia en fragmentos remanentes de bosques nativos y se evaluaron las relaciones entre índices de paisaje y variables de estructura de la vegetación. Los índices de paisaje (área, índice de proximidad media, forma y distancia al borde de fragmentos) fueron aplicados a mapas de cobertura forestal generados a partir de una imagen satelital Landsat ETM+ del año 2001. Los resultados mostraron una alta predominancia de fragmentos de reducido tamaño, altos niveles de aislamiento y formas regulares. El patrón de ocupación de las poblaciones de Legrandia sugiere que las poblaciones ocupan preferentemente fragmentos de menor tamaño y mayor aislamiento. No hubo diferencias significativas entre la distribución de frecuencias de los fragmentos con presencia y sin presencia de Legrandia en cuanto a área y aislamiento. Sin embargo, se obtuvo que el tamaño, aislamiento y la distancia al borde del fragmento se relacionara significativamente con la presencia de la especie. Como medida de conservación de la especie, se recomienda incluir dentro de áreas protegidas a aquellas poblaciones con mayor riesgo a desaparecer, promover su conservación ex situ y establecer un programa de monitoreo. El estudio sienta un precedente respecto a la vinculación entre información a escala de paisaje proveniente de imágenes satelitales e información de estructura de la vegetación medida en terreno, para evaluar el estado de conservación de poblaciones de especies amenazadas que cubren extensiones restringidas de territorio. Esta innovación metodológica ofrece la posibilidad de monitorear los cambios producidos en el tiempo a fin de evaluar la efectividad de determinadas estrategias de conservación para estas poblaciones<br>Habitat fragmentation is one of the main threats to ecosystems integrity. In this study we assessed the influence of forest fragmentation on vegetation structure of populations of tree specie Legrandia concinna in south-central Chile. Occupancy pattern of Legrandia populations in remaining fragments of native forests was described, and relationship between landscape indices and vegetation structure variables were evaluated. Landscape indices, such as area, proximity mean index, shape and edge distance to fragment were applied to forest cover maps generated from a Landsat ETM+ satellite scene for the year 2001. Results showed high predominance of reduced size fragments, high isolation levels and regulars shapes of the fragments. Occupancy pattern suggests that Legrandia populations are found mainly in small and more isolated fragments. No significant difference was found between fragment distribution with and without presence of Legrandia related to size and isolation. However, we found that size, isolation and distance to fragment edge are significantly related to the presence of this specie. As conservation measures for this specie, we propose to include populations with high disappearance risk in protected areas, promote ex situ conservation and set up a monitoring program. This study sets a precedent related by linking landscape scale information obtained from satellite imagery and vegetation structure information measured in the field with conservation status of threatened populations. This innovative method allows monitoring changes over time to assess effectiveness of conservation strategies for these population

Proximity to forest plantations is associated with presence and abundance of invasive plants in landscapes of south-central Chile

Invasive plant species (IPs) are widespread in forests and cause substantial environmental, economic and social impacts. They occupy native ecological niches, causing local extinctions to the detriment of native biodiversity and disrupting ecosystem services provision. How landscape characteristics may determine the success of IPs remains unclear and, more importantly, how land-use and land-cover changes may result in spatial shifts in the invasion risk. Furthermore, the study of how landscape factors may influence biological invasions has focused on particular species, but not the IPs' community. In this study, we identify and assess landscape variables that influence the presence and distribution of the IPs' community in temperate forests of a global biodiversity hotspot in south-central Chile. We fitted spatially explicit models, combining field-sampling information and landscape variables related to land-use/land-cover, topography, climate, soil characteristics and anthropogenic factors to explain and predict the presence and distribution of the IPs' community. From the whole sampling of plant species, we identified eight plant species classified as IPs: three trees and five shrubs. We used field data from 125 500 x 2 m-transects, in which we registered species richness, abundance and basal area of IPs' community. Distance to forest plantations was the landscape variable with the most substantial influence on IPs' presence and distribution. Richness, abundance and basal area of IPs' trees were higher at shorter distances from forest plantations. The basal area of IPs' trees was the best model explaining the relationship between IPs' community and landscape variables. All descriptors of the IPs' community showed similar spatial patterns: species richness, abundance and tree basal area are higher in more disturbed areas. Our findings contribute to increasing our understanding of the distribution patterns of IPs in forest landscapes. Our models can be suitable tools for designing strategies to prevent, mitigate or make integrated control of the impacts of invasive species in forest landscapes

Proximity to forest plantations is associated with presence and abundance of invasive plants in landscapes of south-central Chile

Invasive plant species (IPs) are widespread in forests and cause substantial environmental, economic and social impacts. They occupy native ecological niches, causing local extinctions to the detriment of native biodiversity and disrupting ecosystem services provision. How landscape characteristics may determine the success of IPs remains unclear and, more importantly, how land-use and land-cover changes may result in spatial shifts in the invasion risk. Furthermore, the study of how landscape factors may influence biological invasions has focused on particular species, but not the IPs’ community. In this study, we identify and assess landscape variables that influence the presence and distribution of the IPs’ community in temperate forests of a global biodiversity hotspot in south-central Chile. We fitted spatially explicit models, combining field-sampling information and landscape variables related to land-use/land-cover, topography, climate, soil characteristics and anthropogenic factors to explain and predict the presence and distribution of the IPs’ community. From the whole sampling of plant species, we identified eight plant species classified as IPs: three trees and five shrubs. We used field data from 125 500 × 2 m-transects, in which we registered species richness, abundance and basal area of IPs’ community. Distance to forest plantations was the landscape variable with the most substantial influence on IPs’ presence and distribution. Richness, abundance and basal area of IPs’ trees were higher at shorter distances from forest plantations. The basal area of IPs’ trees was the best model explaining the relationship between IPs’ community and landscape variables. All descriptors of the IPs’ community showed similar spatial patterns: species richness, abundance and tree basal area are higher in more disturbed areas. Our findings contribute to increasing our understanding of the distribution patterns of IPs in forest landscapes. Our models can be suitable tools for designing strategies to prevent, mitigate or make integrated control of the impacts of invasive species in forest landscapes