CARACTERIZACIÓN ESTRUCTURAL DEL BOSQUE PANTANOSO DE MIRTÁCEAS DE LA REGIÓN DE LA ARAUCANÍA, CHILE

Chile swamp forests have a wide and fragmented distribution (1 300 km approx.) and are dominated mainly by mirtaceas. They are associated with poorly drained soils, so their hydroperiods are temporary or permanent. The best-known aspect of these forests is the floristic-vegetation, although information on its structural composition is generally weak and nonexistent for the remnants of the La Araucanía region. The aim of this study was to characterize both vertical and horizontal structure of swampy forests that grow in the locality of Catrimalal, Labranza, Pumalal and Quepe in the central depression of La Araucanía region. In each locality a rectangular plot of 300 m2 was established, tree species present were recorded and basic dasometric parameters were measured. In order to determine differences between the studied localities an analysis of covariance (ANCOVA) and a Tukey test were carried out. The vertical structure consists of four species of trees: Blepharocalyx cruckshanksii (Hook. & Arn.) Nied, Drimys winteri J.R. Forst. & G. Forst., Luma chequen (Molina) A. Gray and Myrceugenia exsucca (DC.) O. Berg, whose general average of height and diameter at breast height (DBH) reach 11.8 m and 22.1 cm. respectively. The horizontal structure shows an average canopy cover of 87% and D. winteri as the species with the highest coverage of crown. Statistical analyzes indicate the presence of significant differences among localities, mainly in Quepe. Low average levels of canopy coverage and height compared to previous descriptions could suggest a human impact on these forests. The difference found in Quepe could be due to a shorter hydroperiod, since this phenomenon regulates among others, the structure of these ecosystems. Swamp forests are essential for the maintenance of groundwater, therefore actions for their protection and conservation are increasingly necessary.Los bosques pantanosos de Chile presentan una distribución amplia y fragmentada (1300 km aprox.), y son dominados principalmente por mirtáceas. Están asociados a suelos con mal drenaje, por lo que sus hidroperiodos son de carácter temporal o permanente. El aspecto más conocido de estos bosques es el florístico-vegetacional, en tanto que información sobre su composición estructural es escasa en general e inexistente para los remanentes de la región de La Araucanía. El objetivo del presente estudio fue caracterizar la estructura vertical y horizontal de bosques pantanosos que prosperan en las localidades de Catrimalal, Labranza, Pumalal y Quepe, en la depresión central de la región de La Araucanía (0709451 E - 5709321 N), Chile. Para lo anterior, en cada localidad se levantó una parcela rectangular de 300 m2, en cada una de ellas se registraron las especies arbóreas presentes y se midieron los parámetros dasométricos básicos. Posteriormente y, con el fin de determinar diferencias entre las localidades estudiadas, se llevó a cabo un análisis de covarianza (ANCOVA) y luego una prueba de Tukey. La estructura vertical se compone de cuatro especies de árboles: Blepharocalyx cruckshanksii (Hook. & Arn.) Nied., Drimys winteri J.R. Forst. & G. Forst., Luma chequen (Molina) A. Gray y Myrceugenia exsucca (DC.) O. Berg, cuyos promedios de altura y diámetro a la altura del pecho (DAP) generales alcanzan los 11.8 m y 22.1 cm, respectivamente. La estructura horizontal muestra una cobertura promedio del dosel arbóreo del 87% y a D. winteri como la especie con las mayores coberturas de copa. Los análisis estadísticos indican la presencia de diferencias significativas entre las localidades estudiadas, principalmente en Quepe. Los bajos valores de cobertura y altura promedio del dosel arbóreo en comparación a descripciones previas, hacen suponer un impacto antrópico en estos bosques. La diferencia de Quepe podría ser consecuencia de un hidroperiodo más corto, ya que dicho fenómeno regula entre otras cosas la estructura de estos ecosistemas. Los bosques pantanosos son esenciales para el mantenimiento de las napas freáticas, por lo que, acciones a favor de su protección y conservación se hacen cada vez más necesarias

Diferencias en la composición florística en bosques de Araucaria- Nothofagus afectados por distintas severidades de fuego

Forest fires can produce significant impacts on the structure and functioning of natural ecosystems. In march 2015, a largescaleforest fire affected Araucaria araucana-Nothofagus pumilio (araucaria-lenga) forests of high ecological value inNational Reserve China Muerta (Chile, 38° S), where fire adaptations are rare among native plants. The goal of this researchwas to evaluate the initial changes of plant composition in the forest along a severity gradient (i.e., high, medium and lowseverity) one year after fire. It is hypothesized that areas more affected by fire will have different species composition fromthe less-fire-affected areas, with decreased richness and abundance of native species, but exotic species will be favored bythe less severe fire. Twenty sampling plots of 100 m2 each were established throughout the fire-severity gradient, including anadjacent unburned forest that served as reference. Species richness and abundance of all vascular plants (native and exotic)were recorded in each plot. We analyzed and compared species richness and abundance of natives and exotics, and the floristiccomposition and similarity between the different levels of severity. The results show that species richness and abundancewere significantly lower in areas of high and medium fire-severity compared to areas less-affected by fire. The richness andabundance of exotic species were greater in areas of low fire-severity, which were subject to cattle grazing after the fire. Thisresearch shows a rapid compositional change in the vascular plant community in Araucaria-Nothofagus forests one year afterfire, and raises the potential for change in the forest structure if dominant tree species are unable to recover after fire.El fuego tiene impactos importantes en la estructura y funcionamiento de ecosistemas naturales. En marzo de 2015 unincendio de gran magnitud afectó bosques de alto valor ecológico de Araucaria araucana-Nothofagus pumilio (araucarialenga)en la Reserva Nacional China Muerta (Chile, 38° S), donde las adaptaciones al fuego son poco frecuentes en la floranativa. El objetivo del presente trabajo fue evaluar los cambios en la composición florística del bosque en un gradientede severidad de fuego (i.e., alta, media y baja severidad) un año después del disturbio. Se hipotetiza que las zonas másafectadas por el fuego presentarán una composición de especies distinta a la de zonas menos afectadas, con una menorriqueza y abundancia de especies nativas, y que las especies exóticas se verán favorecidas por el fuego poco severo. Seestablecieron 20 parcelas de 100 m2 cada una en todo el gradiente de severidad de fuego, incluyendo un bosque adyacenteno quemado que sirvió como referencia. En cada parcela se registró la riqueza y abundancia de toda la flora vascular(nativas y exóticas). Se analizó y comparó la riqueza y abundancia de especies, la composición y similitud florística entrelos distintos niveles de severidad. Se encontró que la riqueza y abundancia de especies son significativamente más bajasen áreas de alta y media severidad de fuego. La riqueza y abundancia de especies exóticas fue mayor en áreas de bajaseveridad de fuego, las cuales estuvieron sujetas a pastoreo después del fuego. Existe un rápido cambio composicional de lacomunidad de plantas en el bosque de Araucaria-Nothofagus un año después del incendio, sugiriendo un potencial cambioen la estructura del bosque si las especies arbóreas dominantes no se recuperan después del fuego

Differences in floristic composition of Araucaria-Nothofagus forests affected by mixed levels of fire severity

El fuego tiene impactos importantes en la estructura y funcionamiento de ecosistemas naturales. En marzo de 2015 un incendio de gran magnitud afectó bosques de alto valor ecológico de Araucaria araucana-Nothofagus pumilio (araucarialenga) en la Reserva Nacional China Muerta (Chile, 38° S), donde las adaptaciones al fuego son poco frecuentes en la flora nativa. El objetivo del presente trabajo fue evaluar los cambios en la composición florística del bosque en un gradiente de severidad de fuego (i.e., alta, media y baja severidad) un año después del disturbio. Se hipotetiza que las zonas más afectadas por el fuego presentarán una composición de especies distinta a la de zonas menos afectadas, con una menor riqueza y abundancia de especies nativas, y que las especies exóticas se verán favorecidas por el fuego poco severo. Se establecieron 20 parcelas de 100 m2 cada una en todo el gradiente de severidad de fuego, incluyendo un bosque adyacente no quemado que sirvió como referencia. En cada parcela se registró la riqueza y abundancia de toda la flora vascular (nativas y exóticas). Se analizó y comparó la riqueza y abundancia de especies, la composición y similitud florística entre los distintos niveles de severidad. Se encontró que la riqueza y abundancia de especies son significativamente más bajas en áreas de alta y media severidad de fuego. La riqueza y abundancia de especies exóticas fue mayor en áreas de baja severidad de fuego, las cuales estuvieron sujetas a pastoreo después del fuego. Existe un rápido cambio composicional de la comunidad de plantas en el bosque de Araucaria-Nothofagus un año después del incendio, sugiriendo un potencial cambio en la estructura del bosque si las especies arbóreas dominantes no se recuperan después del fuegoForest fires can produce significant impacts on the structure and functioning of natural ecosystems. In march 2015, a largescale forest fire affected Araucaria araucana-Nothofagus pumilio (araucaria-lenga) forests of high ecological value in National Reserve China Muerta (Chile, 38° S), where fire adaptations are rare among native plants. The goal of this research was to evaluate the initial changes of plant composition in the forest along a severity gradient (i.e., high, medium and low severity) one year after fire. It is hypothesized that areas more affected by fire will have different species composition from the less-fire-affected areas, with decreased richness and abundance of native species, but exotic species will be favored by the less severe fire. Twenty sampling plots of 100 m2 each were established throughout the fire-severity gradient, including an adjacent unburned forest that served as reference. Species richness and abundance of all vascular plants (native and exotic) were recorded in each plot. We analyzed and compared species richness and abundance of natives and exotics, and the floristic composition and similarity between the different levels of severity. The results show that species richness and abundance were significantly lower in areas of high and medium fire-severity compared to areas less-affected by fire. The richness and abundance of exotic species were greater in areas of low fire-severity, which were subject to cattle grazing after the fire. This research shows a rapid compositional change in the vascular plant community in Araucaria-Nothofagus forests one year after fire, and raises the potential for change in the forest structure if dominant tree species are unable to recover after fir

Impacts of fragmentation on floristic composition of swamp forests in south-central Chile

Los bosques pantanosos del centro-sur de Chile han sido fuertemente alterados por la fragmentación del paisaje, derivada principalmente de actividades antrópicas. A pesar de su alto valor ecológico y de conservación para la biodiversidad, estos ecosistemas han sido poco estudiados. El objetivo de este estudio fue evaluar la riqueza de plantas vasculares en distintos fragmentos de bosque pantanoso de la región de La Araucanía (38° S, Chile). Se estudiaron 11 fragmentos en total, en los cuales se definieron zonas de borde y núcleo. Se levantaron transectos florísticos y se identificaron todas las especies de plantas vasculares. Se determinaron diferencias en la composición florística entre el borde y núcleo, y se realizó un GLM para modelar la respuesta de la riqueza de especies en función de la superficie de los fragmentos y el origen geográfico de las plantas. Los resultados mostraron un total de 123 especies de plantas, de las cuales 76 son nativas y 47 son no-nativas. La composición florística difiere significativamente entre zonas de borde y núcleo, y la riqueza de especies está influenciada por la superficie de los fragmentos y el origen geográfico de las plantas. Nuestro estudio concluye que el tamaño de los fragmentos y las características de la matriz circundante son variables fundamentales que influencian la composición florística de los bosques pantanosos en el centro-sur de ChileThe swamp forests of south-central Chile have been greatly altered by the fragmentation of the landscape, which is mainly derived from anthropogenic activities. Despite their high ecological and conservation value for the biodiversity, these ecosystems have been scarcely studied. The main goal of this study was to evaluate the richness of vascular plants in different fragments of swamp forests in the Araucania region (38 degrees S, Chile). A total of 11 fragments were studied, in which edge and core zones were defined. Floristic transects were established, and we recorded and identified all species of vascular plants. Differences in the floristic composition between the edge and the core zones were determined, and we performed a GLM to model the response of species richness according to the area of the fragments and the geographical origin of the plants. A total of 123 species of plants were found across all fragments, of which 76 were native and 47 were non-native species. The floristic composition differs significantly between edge and core zones, and the GLM revealed that species richness is influenced by the area of the fragments and the geographical origin of the plants. Our study concludes that the size of the fragments, as well as by the characteristics of the surrounding matrix are fundamental variables that influence the floristic composition of swamp forests in south-central Chil

Variación del número cromosómico en parte de la flora de áreas silvestres protegidas en la Región de la Araucanía, sur de Chile

An analysis was made of the correspondence between species diversity and chromosome number (CN) diversity across 13 Protected Wild Areas (PWA) in the Araucanía Region of southern Chile, encompassing 84 plant species with available cytogenetic data. Our aim was to establish whether higher species diversity within a PWA entails higher CN variation as based on the index of chromosome number heterogeneity (ICNH). The CN data were extracted from databases for Chilean plants, and the ICNH for the flora of each PWA was calculated. Results showed that in nine PWA the species diversity clearly correlates with CN diversity. However, four PWA do not fit this trend. The percentage of species with CN data varied between 9.6% and 24.5% among PWA, with 11 PWA presenting percentages higher than 11%. A 27.3% of the Chilean vascular plant species with available cytogenetic data were studied here for the 13 PWA. The results obtained by studying one part of the flora with available CN data suggest that the PWA could be an important reservoir of genetic diversity at a chromosome level, thus justifying the protective role of the PWA as biodiversity conservation sites

Efectos de una zona urbana sobre la comunidad de macroinvertebrados bentónicos de un ecosistema fluvial del sur de Chile

A healthy body of freshwater can provide numerous benefits to the society, although currently, the degradation of such ecosystems has been increased due to the establishment of urban areas along its riverbanks. In this study we analyzed the spatial effect of these zones on the water quality, using the benthonic macroinvertebrate communities as bioindicators of fluvial contamination in the Gibbs channel of the Temuco commune (38°46°'S 72°38°'W). The samplings were performed in spring, in six sites. The macrozoobentos was composed by a total of 15 taxa, corresponding to organisms tolerant to anoxic conditions and high concentrations of organic matter, such as amphipods (Hyalella), dipterans (Quironomidae), and oligochaetes (Oligochaeta). There was a marked difference in the composition and abundance of taxa between the pre-urban, urban, and post-urban areas (ANOSIM Global R = 0.882, p = 0.001) tendency that was also recorded by the physicochemical parameters (ANOSIM Global R = 0.498, p = 0.001), of which pH, total suspended solids, and dissolved oxygen are those that best explained the patterns observed in the macrozoobentos. The results obtained with the biotic family index (ChIBF) were similar to those registered in the lower parts of the basins of southern Chile and the invertebrate community was shown to be sensitive to anthropogenic disturbances. © Asociación Ibérica de Limnología, Madrid

World distribution, diversity and endemism of aquatic macrophytes

To test the hitherto generally-accepted hypothesis that most aquatic macrophytes have broad world distributions, we investigated the global distribution, diversity and endemism patterns of 3457 macrophyte species that occur in permanent, temporary or ephemeral inland freshwater and brackish waterbodies worldwide. At a resolution of 10 × 10° latitude x longitude, most macrophyte species were found to have narrow global distributions: 78% have ranges (measured using an approach broadly following the IUCN-defined concept “extent of occurrence”) that individually occupy <10% of the world area present within the six global ecozones which primarily provide habitat for macrophytes. We found evidence of non-linear relationships between latitude and macrophyte α- and γ-diversity, with diversity highest in sub-tropical to low tropical latitudes, declining slightly towards the Equator, and also declining strongly towards higher latitudes. Landscape aridity and, to a lesser extent, altitude and land area present per gridcell also influence macrophyte diversity and species assemblage worldwide. The Neotropics and Orient have the richest ecozone species-pools for macrophytes, depending on γ-diversity metric used. The region around Brasilia/Goiás (Brazil: gridcell 10–20 °S; 40–50 °W) is the richest global hotspot for macrophyte α-diversity (total species α-diversity, ST: 625 species/gridcell, 350 of them Neotropical endemics). In contrast, the Sahara/Arabian Deserts, and some Arctic areas, have the lowest macrophyte α-diversity (ST <20 species/gridcell). At ecozone scale, macrophyte species endemism is pronounced, though with a>5-fold difference between the most species-rich (Neotropics) and species-poor (Palaearctic) ecozones. Our findings strongly support the assertion that small-ranged species constitute most of Earth’s species diversity

Cytogenetics of Chilean angiosperms: Advances and prospects

Cytogenetic data on Chilean angiosperms have been reported since at least eight decades ago; however, much of this information is disperse in diverse sources and is not readily available as a comprehensive document that allows having a general vision on advances and gaps in this matter. The goal of this paper is to summarize the advances and prospets on cytogenetic studies of the Chilean angiosperms based on compiled publications from 1929 to 2010. We found 78 publications supplied by four groups of Chilean researchers and some foreign specialists. Cytogenetic data have been reported for 139 Chilean angiosperm species (2.8 % of the total), which belong to 58 genera and 34 families. During 2001-2010 there was an increase in the number of publications, being available 40 reports including 95 additional species. Based on these data, we hope that such a trend can be maintained in the next decade if the current research groups and young specialists continue to be interested in the study of native plants

Differences in floristic composition of Araucaria-Nothofagus forests affected by mixed levels of fire severity

Forest fires can produce significant impacts on the structure and functioning of natural ecosystems. In march 2015, a large-scale fort fire affected Araucaria ansucana-Nothofagus pumilio (araucaria-lenga) forts of high ecological value in National Reserve China Muerta (Chile, 38 degrees S), where fire adaptations are rare among native plants. The goal of this research was to evaluate the initial changes of plant composition in the forest along a severity gradient (i.e., high, medium and low severity) one year after fire. It is hypothesized that areas more affected by fire will have different species composition from the less-fire-affected areas, with decreased richness and abundance of native species, but exotic species will be favored by the less severe fire. Twenty sampling plots of 100 m(2) each were established throughout the fire-severity gradient, including an adjacent unburned forest that served as reference. Species richness and abundance of all vascular plants (native and exotic) were recorded in each plot. We analyzed and compared species richness and abundance of natives and exotics, and the floristic composition and similarity between the different levels of severity. The results show that species richness and abundance were significantly lower in areas of high and medium fire-severity compared to areas less-affected by fire. The richness and abundance of exotic species were greater in areas of low fire-severity, which were subject to cattle grazing after the fire. This research shows a rapid compositional change in the vascular plant community in Araucaria-Nothofagus forests one year after fire, and raises the potential for change in the forest structure if dominant tree species are unable to recover after fire