66 research outputs found

    Patrones de diversidad de plantas trepadoras y epifitas vasculares en el bosque lluvioso valdiviano de Sudamérica: Una síntesis entre los años 2000 y 2010

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    Knowledge about the diversity patterns of vascular epiphytes and vines in the Valdivian rainforest of South America between 2000 and 2010 was systematized. The method was based on the review of publications available in four electronic databases using keywords. The results showed 12 studies conducted in Chile and two in Argentina, mostly in primary forests within protected areas. Research was carried out essentially at the habitat level, although there were one study at a landscape level and two reviews at a regional scale. The samples used came from ground-based observations and only two studies accessed the canopy of emergent trees. The most relevant findings showed that: (1) diversity was greater in primary than secondary forests; (2) the abundance of epiphytic ferns (Hymenophyllaceae) correlated positively with the habitat moisture gradient; (3) climbing plants showed differential tolerance to shade; (4) the diversity of both groups of plants was positively correlated with the diameter of phorophytes, and (5) the majority of vines and epiphytes showed selectivity for the phorophyte species. In addition, richness of vascular epiphytes and vines at a habitat scale ranged from 8 to 16 and 6 to 14 species, respectively. Knowledge about the level of species interchange between habitats is scarce in fragmented environments and at a landscape scale. This knowledge must be prioritized in areas with high human pressure to improve the conservation opportunity of this group of plants

    Climate change and its effects on urban spaces in Chile: A summary of research carried out in the period 2000-2012

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    We have systematized the effects associated with climate change on urban spaces in Chile reported between 2000 and 2012. The method was based on a review of scientific articles in three databases (Scopus, Web of Knowledge and Scielo) using 32 keywords. Only 14 research papers were found related to climate change in urban spaces, most of which were case studies focused on the capital, Santiago. The main effects on urban spaces were found in four areas: (1) increase in temperature (heat islands, heat waves), (2) health problems in vulnerable populations (cardiac complications, heat stroke, and respiratory diseases), (3) increased demand for water, and (4) damage to the urban infrastructure with resulting risk to the population. In these circumstances the following measures are needed: (1) effective incorporation of the potential impacts of climate change into territorial planning instruments, (2) increased green areas to mitigate the impact of heat waves, (3) limiting of housing or public services in areas at risk, (4) encouraging the design of adaptation plans by involving the vulnerable population, and (5) implementing water conservation measures. We conclude that climate change is causing effects in urban areas that should be considered in the design and expansion of cities.Se sistematizaron los efectos asociados al cambio climático sobre los espacios urbanos en Chile entre los años 2000 y 2012. El método se basó en la revisión de artículos científicos en tres bases de datos (Scopus, Web of Knowledge y Scielo) mediante el uso de 32 palabras claves. Los resultados mostraron sólo 14 investigaciones que relacionan el cambio climático en espacios urbanos, la mayoría de las cuales fueron estudios de casos centrados en la capital nacional. Los principales efectos sobre los espacios urbanos se basaron en cuatro aspectos: 1) incremento de temperatura (islas de calor, olas de calor), 2) problemas de salud en la población más vulnerable (complicaciones cardiacas, insolación, enfermedades respiratorias), 3) incremento en la demanda de agua y 4) daños en la infraestructura urbana con el consiguiente riesgo para la población. Ante este fenómeno se requiere: 1) la incorporación efectiva de los posibles impactos del cambio climático en los instrumentos de planificación territorial, 2) incremento de las áreas verdes que permita mitigar los impactos de las olas de calor, 3) limitar la construcción de viviendas o servicios públicos en áreas de riesgo, 4) incentivar el diseño de planes de adaptación haciendo participe a la propia población vulnerable y 5) implementar medidas de conservación del agua. Se concluye que el cambio climático está generando en los espacios urbanos efectos que deben considerarse para el diseño y expansión de las ciudades

    Patch size and shape and their relationship with tree and shrub species richness

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    Se relacionó el tamaño y forma de 10 fragmentos de bosque nativo con la riqueza de especies de árboles y arbustos en la precordillera costera de la provincia de Osorno, sur de Chile. Se ajustaron cuatro modelos de regresión (lineal, logarítmico, exponencial y potencial), entre el tamaño de fragmentos (área = x) y la riqueza de especies de árboles y arbustos (número de especies = y). Se cuantificó la forma de los fragmentos a través de tres índices (índice de diversidad de Patton, índice de compactación y dimensión fractal), y se obtuvieron las correlaciones parciales entre el área y la riqueza de especies controlando el efecto recíproco del área y el perímetro. Los resultados permitieron concluir que: la riqueza de especies tiende a aumentar significativamente con el tamaño del fragmento, relación que fue explicada por los cuatro modelos. No obstante, el mejor ajuste se logró con el modelo de regresión lineal simple, con un R2 de 65,1% (y = 5,9 + 0,15x); las formas de los fragmentos fueron en general complejas asemejándose a la de objetos fractales, y el área fue el factor que explicó de modo más consistente la riqueza de especies (rxy.z = 0,699); la forma no tuvo un efecto significativo en las variaciones de riqueza de especies de árboles y arbustos

    Land use change in the geosystem coastal basin of the Boroa river (Chile) between 1994 and 2004

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    Se analizaron los principales cambios de uso del suelo en las unidades de paisaje (geosistemas) de la cuenca hidrográfica del río Boroa entre 1994 y 2004. Para ello se planteó la hipótesis de que los cambios en la estructura del paisaje han sido conducidos fundamentalmente por acción antrópica generando importantes alteraciones en el paisaje ecológico. Se utilizaron mapas categóricos de uso/cobertura de suelo elaborados con material cartográfico y fotografías aéreas con su posterior corrección en terreno, información que fue complementada con el análisis geomorfológico y de unidades ambientales de la cuenca. Se comprobó una fuerte variación en la superficie de plantaciones forestales (principalmente Eucalyptus spp.), con una tasa de incremento anual que varió entre 3,2 y 28%, asociado principalmente a reconversión de uso y ocupación de cordones montañosos metamórficos. A su vez, se constató la expansión de zonas de humedales en terrenos anegadizos de llanuras, todo lo cual ha reducido la superficie total con destino agrícola en 61%, transformando el paisaje en un periodo de sólo diez años. Estos cambios se discuten sobre la base de una combinación de factores económicos, legales y ambientales, concluyendo que el factor humano ha sido el principal responsable de la conducción de los cambios de uso del suelo en la cuenca del río Boroa.We analyzed the major changes in land use in the landscape units (geosystems) of Boroa river basin between 1994 and 2004. To do this, we hypothesized that changes in landscape structure have been driven primarily by human action, generating significant changes in the ecological landscape. Categorical maps of use/land cover made from aerial photographs, cartographic material and its subsequent correction in the field were used. This information was complemented by an analysis of the geomorphology and environmental units of the basin. Significant variation was found in the area of forest plantations (mainly Eucalyptus spp.) which varied between 3.2 and 28%, associated principally with the conversion of the use and occupation of metamorphic mountain chains. At the same time, the expansion in wetlands areas on waterlogged soils was found, all of which have reduced the total agricultural area in 61%, transforming the landscape into a period of only ten years. These changes are discussed on the basis of a combination of economic, legal and environmental, concluding that the human factor has been primarily responsible for driving changes in land use in the Boroa river basin.Fil: Peña-Cortés, Fernando. Universidad Católica de Temuco. Facultad de Recursos Naturales. Escuela de Ciencias Ambientales. Laboratorio de Planificación TerritorialFil: Escalona-Ulloa, Miguel. Universidad Católica de Temuco. Facultad de Recursos Naturales. Escuela de Ciencias Ambientales. Laboratorio de Planificación TerritorialFil: Pincheira-Ulbrich, Jimmy. Universidad Católica de Temuco. Facultad de Recursos Naturales. Escuela de Ciencias Ambientales. Laboratorio de Planificación TerritorialFil: Rebolledo, Gonzalo. Universidad Católica de Temuco. Facultad de Recursos Naturales. Escuela de Ciencias Ambientales. Laboratorio de Planificación Territoria

    Consequences of swamp forest fragmentation on assemblages of vascular epiphytes and climbing plants: Evaluation of the metacommunity structure

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    Aim Habitat reduction in fragmented landscapes provides an opportunity to study the biogeographic patterns that drive changes in diversity in poorly studied metacommunities. In this study, colonization-extinction dynamics were indirectly evaluated through the analysis of the species-area relationship and the nestedness of vascular epiphytes and climbing plants in 30 swamp forest fragments. Location Coast of the Araucania Region in Chile. Taxon Vascular epiphytes (16 species, mainly Pteridophytes) and climbing plants (15 species). Methods We used the database in Pincheira-Ulbrich et al. (New Zealand Journal of Botany, 54, 2016, 458), where 904 trees were sampled and a total abundance of 41,097 fern fronds and 3,098 climbing stems were reported. For the species-area relationship, a simple linear regression model (SLR) and two models that consider the spatial autocorrelation of species richness among fragments, generalized least squares (GLS) and simultaneous autoregressive model (SAR), were compared. For the species nestedness, the nestedness measure based on overlap and decreasing fills (NODF) and weighted nestedness metric based on overlap and decreasing fill (WNODF) indexes were used on presence-absence and abundance matrices, respectively. These matrices were sorted by area size and distance from the largest fragment and then contrasted with the probability distribution of a randomized null model based on 10,000 simulations. Results The results showed that the area size had a significantly positive effect on epiphyte species richness, while spatial autocorrelation played a fundamental role in explaining the richness of climbing plants. Both metacommunities had a general nestedness structure in terms of species incidence, which was determined first by area size and secondly by isolation. Main conclusions Our results indicate that local colonization processes determined by species' dispersal capacities could be the predominant mechanism for the spatial configuration of climbing plant species composition. On the other hand, selective extinction determined by patch size could characterize the spatial structure of epiphyte species' compositio

    Tree and shrub diversity in native rainforest fragments in southern Chile

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    We sampled the diversity of trees and shrubs, and built the rarefaction and accumulation species curve in 10 native forest fragments in southern Chile. Results indicated that: (1) there were 23 species in all sampled fragments, (2) species richness increased significantly with fragment size, (3) all fragments require a minimal sampling from 40 to 170 individuals to reach the maximum theoretical species richness, and (4) sampling richness was greater than that theoretically expected (20 species)

    A study of the geographic distribution of swamp forest in the coastal zone of the Araucanía Region, Chile

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    A study was made of the geographic distribution of swamp forest in the coastal territory of the Araucanía Region, Chile. An analysis of maps, aerial photographs, and satellite images was carried out, together with field work, to determine the location, degree of fragmentation, shape of fragments and habitat use of the forest. The results showed a total area of 7675 ha of forest (in a region of 165,168 ha) divided into 427 fragments of highly irregular shapes, set in a farming matrix. This forest type was located principally on alluvial (37%) and fluvial-marine (33%) plains associated with the Toltén and Queule river basins. Land unsuitable for agriculture accounted for 50% of the area of forest (CIREN Classes VII and VIII), while land with a superficial phreatic water table (0-20 cm depth) and poorly drained soils concentrated 47% and 66% of the forest respectively. The majority of the forested area stands on soils with poor drainage (available habitat), as a response to the greater biophysical restrictions which such areas represent for agriculture. Of the forested area, 59% was located on 859 properties belonging to small-holders with up to 200 ha, while 39% was located on 58 medium to large properties (over 200 ha and over 1000 ha respectively). Forty percent of the forest is within 300 m of a road and only 8% is more than 1000 m away. It is concluded that the forest is under severe pressure from human activity (by clearing for agricultural land, grazing and firewood extraction) and that there is an urgent need for a plan giving priority to conservation. © 2010 Elsevier Ltd

    The conservation status of raptors in Chile

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    We classified 30 species of raptors in Chile using the technique proposed by Reca et al. (1994) and the conservation categories proposed by Grigera and Úbeda (2000). The results were obtained by means of an index that considers 12 variables that represent factors of importance for the survival or the conservation of the species. Eight species (27%) were classified in the category of maximum priority, nine (30%) in the special attention category, and 13 (43%) in the no priority category. Strix rufipes and Buteo exsul were considered with the highest priority of conservation, and together with Accipiter chilensis, Buteo albigula, Buteo ventralis, Phalcoboenus australis, Vultur gryphus, and Phalcoboenus albogularis conform the category of maximum priority conservation. Diurnal raptors (Falconiformes) need a greater conservation priority than nocturnal raptors (Strigiformes). At the family level, Accipitridae had the highest species richness and also showed major conservation problems. We concluded that the technique is a useful tool with simple application that allows orienting the public conservation decisions on this taxonomic group

    Morphology and dune dynamics in the coastal border of Araucania region in Chile : Background for conservation and territorial management

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    An evaluation was made of the dynamics of the dune systems of the coastal strip of the Araucanía region between 1994 and 2004, based on its morphological classification and degree of stabilization as evaluated from cartographic material, aerial photographs and investigation in the field. Eight fields of dunes were defined with a total surface area of 4,597 ha being stated a total expansion of 314 ha in the period; active dunes represented 35% of the total area, while semi-stabilized and stabilized dunes represented 31% and 15% respectively. The most common type of morphology was transverse dunes and the most frequent plant species were Pinus radiata and Ammophila arenaria. Finally, the localization and the determination of the stabilization grades and dunaries shapes allow to recognize the action of the natural and anthropic factors, these integrally require to be tackle as a frame for an integrated management of this coastal zone.Se evaluó la dinámica de los campos dunarios del borde costero de La Araucanía entre los años 1994 y 2004, usando para ello la clasificación morfológica y grado de estabilización, evaluado a partir de material cartográfico, fotografías aéreas y reconocimiento en terreno. Se delimitaron 8 campos de dunas distribuidos en una superficie de 4.597 ha, constatándose una expansión total de 314 ha en el periodo; las dunas activas representaron un 35% de esta superficie, mientras que las dunas semiestabilizadas y estabilizadas representaron un 31 y 15% respectivamente. La morfología más frecuente fue el tipo de duna transversal y las especies vegetales con mayor frecuencia fueron Pinus radiata y Ammophila arenaria. Finalmente, la localización y la determinación de los grados de estabilización y formas dunarias permiten reconocer la acción de factores naturales y antrópicos, los que requieren ser abordados integralmente como base para una gestión integrada de esta zona costera

    Has land use pushed terrestrial biodiversity beyond the planetary boundary? A global assessment

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    Land use and related pressures have reduced local terrestrial biodiversity, but it is unclear how the magnitude of change relates to the recently proposed planetary boundary (“safe limit”). We estimate that land use and related pressures have already reduced local biodiversity intactness—the average proportion of natural biodiversity remaining in local ecosystems—beyond its recently proposed planetary boundary across 58.1% of the world’s land surface, where 71.4% of the human population live. Biodiversity intactness within most biomes (especially grassland biomes), most biodiversity hotspots, and even some wilderness areas is inferred to be beyond the boundary. Such widespread transgression of safe limits suggests that biodiversity loss, if unchecked, will undermine efforts toward long-term sustainable development
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