The expansion of cities promotes the replacement of local biotas with exotic species causing a decrease in global diversity. As urbanization continues to expand, efforts directed towards the conservation within urban landscapes could support regional biodiversity conservation. The biogeographic region of central Chile displays a native flora of global importance because of its high endemism. Up to date, studies analysing the composition of the floras within the cities are scarce. The present study aims at characterizing the compositional and distributional patterns of the ornamental flora of five cities of central Chile (La Serena, Valparaíso, Santiago, Rancagua, and Talca). For this purpose, we sampled several streets and squares recording all woody species. The species were then characterized by their biogeographical origin and incidence. It was recorded 302 species of which approx. 86% were exotic and 14% were native, a consistent pattern found in the five cities studied; these results contrast with the European urban flora, where native species can usually overcome 50% of the plant species. Almost half of the exotic species had their origin in Asia (including Australasia, Temperate, and Tropical Asia), Europe, and North America. Consequently, the representation of the regional flora within the urban context is low for central Chile, with the native species registered, accounting for only 0.81% of the total species described for the country. Urban habitats could support regional biodiversity conservation, so a shift towards sustainable urban planning could promote local biological conservation. KEYWORDS:Native species, plant conservation, urban flora, urban trees. RESUMENLa expansión de las ciudades promueve el reemplazo de biotas locales (nativas) por especies exóticas, lo que causa una disminución en la diversidad. A medida que la urbanización continúa, los esfuerzos dirigidos a la conservación dentro de los paisajes urbanos podrían apoyar la conservación de la biodiversidad regional. La región biogeográfica de Chile Central muestra una flora nativa de importancia mundial debido a su alto endemismo. No obstante, hasta la fecha hay pocos estudios que analicen la composición de las floras dentro de las ciudades de esta región. El presente estudio analiza la composición de la flora ornamental para cinco ciudades de Chile central: La Serena, Valparaíso, Santiago, Rancagua y Talca. Para ello realizamos un muestreo de calles y plazas de estas ciudades, registrando especies de plantas leñosas, distinguiendo su origen biogeográfico y su incidencia. Se registraron 302 especies de las cuales aprox. el 86% fueron especies exóticas y el 14% nativas, patrón numéricamente consistente en las cinco ciudades estudiadas. Casi la mitad de las especies exóticas provienen de Asia (incluyendo Australasia y Asia tropical y templada), Norteamérica y Europa. En consecuencia, la representación de la flora regional dentro del contexto urbano es baja para el centro de Chile. Los habitats urbanos podrían apoyar la conservación de la bio...
Mitotic chromosome counts in Chilean pteridophytes confirm the diploidy described for Equisetum L. (2n = 216) and Blechnum L. (2n = 66), as well as the tetraploidy of Asplenium L. (2n = 144). Megalastrum spectabile (Kaulf.) A.R.Sm. et R.C.Moran is diploid (2n = 82), while in metaphases of Polystichum subintegerrimum (Hook. et Arn.) R.A.Rodr. chromosome numbers from ca. 311 to 328 were counted. Tetraploidy was also described in Adiantum chilense Kaulf. (2n = 116).
The karyotype of Luzuriaga radicans R. & P. was quantitatively studied, assessing characters such as chromosome morphology and size, satellite location, asymmetry level and bimodality. L. radicans has an asymmetric and bimodal karyotype 2n = 20 with three metacentric pairs, followed by six submetacentric and one subtelocentric chromosome pair. One satellite was observed in the short arm of chromosome pair 6. The total haploid set length was 48.7 µm and the mean chromosome size was 4.87 ± 2.35 µm. Comparing L. radicans with other two species of the genus a high resemblance among their karyotypes was found.
The zooplankton assemblages in Chilean Patagonian lakes are characterised mainly by their low biodiversity and high predominance of calanoids copepods, a pattern that has been studied for large and deep lakes between 38-51° S, and shallow ponds at 51° S. The aim of the present study was analyse the zooplankton assemblages in different water bodies located in coastal zones, middle valleys and mountain zones between 37-39° S. For this purpose, the following variables were considered: maximum depth, latitude, altitude, chlorophyll-a and species number, and to these variables, a Principal Component Analysis (PCA) was applied. A co-occurrence null model analysis was also applied for determining the existence of a random process in crustacean species associations. The results denoted low species richness, and different species associations for studied sites, and the null model analysis revealed the absence of a random process as regulator of species associations. Furthermore, a low species/genera ratio was identified, which denotes low productivity of the studied sites. These results were supported by a PCA analysis which denoted that the main determinant factors are chlorophyll concentration and species number that are directly associated. The obtained results are in agreement with descriptions in the literature for species diversity for lakes of Chilean Patagonia that describes oligotrophy as the main regulator of zooplankton assemblages. Other ecological and limnological topics are discussed in the present study.
ABSTRACT. Chilean Patagonia has protected mountainous areas with evergreen native forests; in which the lakes and rivers, of volcanic or glacial origin, are oligotrophic. In Bulgaria, there are mountainous zones with native forests and associated lakes of volcanic origin. The aim of the present study is to carry out a preliminary comparison of zooplanktonic crustaceans in lake ecosystems associated with native forests of Chilean Patagonia and of Bulgarian mountains. The study revealed that the lakes studied in Chilean Patagonia are associated mainly with Nothofagus forests; they are oligotrophic, with a low number of zooplanktonic crustacean species. Similar results were observed for Bulgarian mountain lakes associated with Fagus forests. A null model analysis of species co-occurrence was applied to the two groups of lakes, and the result revealed the absence of regulatory factors in species associations. These studies agree with similar descriptions of lakes in Andean Patagonia and New Zealand. They highlight the important role of native Nothofagus forests in Argentina and Chile, and of Fagus forests with associated soil properties in Bulgaria, in the oligotrophy of the lakes studied.
Recuperación natural del bosque siempreverde afectado por tala rasa y quema en la Reserva Costera Valdiviana, Chile SUMMARYThis study aimed at understanding the natural recovery of the evergreen forest a decade after being affected by clearcutting and burning, in a site located in the Valdivian Coastal Reserve (39°56' S-73°40' W). A total of 27 circular (50.2 m 2 ) plots with eight subplots each were established. Floristic composition was recorded and quantitative, diametric and age structures were determined. The results show a richness of 77 vascular species (84.4 % natives), with Lophosoria quadripinnata presenting the highest relative cover (20.7 %). The presence of hemicryptophytes (35 %) indicates human intervention in the place. Trees were the main form of growth, being Drimys winteri, Saxegothaea conspicua and Amomyrtus luma the species with higher plant density. The latter two species growing under Chusquea macrostachya and Lophosoria quadripinnata cover. Drimys winteri and Embothrium coccineum were established immediately after the anthropogenic disturbance of clearcutting and burning, confirming the pioneering character of these two species after highly severe disturbances. Regeneration of Nothofagus nitida was scarce in the area, probably associated with low availability and seed dispersal capacity from surrounding forests. Understanding the early response of evergreen forests affected by anthropogenic disturbance is very important for assisting and guiding the ecological restoration of these forest ecosystems.Key words: evergreen forest, clearcutting, burning, floristic diversity. RESUMENEl presente estudio tuvo como objetivo comprender la recuperación natural del bosque siempreverde afectado por tala rasa, quema y abandono hace más de una década en un sitio ubicado en la Reserva Costera Valdiviana (39° 56' S -73° 40' O). Se establecieron 27 parcelas circulares (50,2 m 2 ) y ocho subparcelas en cada una de ellas, registrando la composición florística y determinando la estructura cuantitativa, diamétrica y etárea. Los resultados indican una riqueza de 77 especies de plantas vasculares (84,4 % nativas), donde Lophosoria quadripinnata presenta la mayor cobertura relativa (20,7 %). La presencia de un 35 % de hemicriptófitas evidencia el fuerte impacto antrópico ocurrido en el área de estudio. La principal forma de crecimiento es la arbórea, donde Drimys winteri, Saxegothaea conspicua y Amomyrtus luma presentaron la mayor densidad. Estas dos últimas especies se desarrollaron bajo la cobertura de Chusquea macrostachya y Lophosoria quadripinnata. Drimys winteri y Embothrium coccineum se establecieron inmediatamente luego del disturbio antrópico de tala rasa y quema, confirmando el carácter pionero de ambas especies luego de disturbios de gran severidad. La regeneración de Nothofagus nitida fue escasa en el área, probablemente asociada a la baja disponibilidad y capacidad de dispersión de semillas desde bosques aledaños. La comprensión de la respuesta temprana de los bosques siempreverdes afectados por dis...
The zooplankton assemblages in deep, mostly oligotrophic northern Patagonian lakes are characterized by low species numbers and a marked dominance of calanoid copepods. In the present study, data collected in field work on six water bodies located in Alerce Andino National Park (41°S) were analysed using the Jaccard Index of community similarity and a co-occurrence of null models, and such with the aim of determining potential regulating factors for the observed crustacean assemblages, using a presence-absence matrix. A significant correlation between species number and surface area was found. The null model used species co-occurrence, and the basis of this model is that the species associations observed are random. The results revealed the absence of regulating factors and indicate that the sites are relatively homogeneous, with low species numbers and similar plankton assemblages at all studied sites. This finding is in accordance with similar descriptions for zooplankton assemblages in other Chilean Patagonian lakes. RESUMENLos ensambles zooplanctónicos en lagos del norte de la Patagonia se caracterizan por su bajo número de especies y marcada dominancia de copépodos calanoideos. En el presente trabajo se colectaron datos de seis cuerpos de agua del Parque Nacional Alerce Andino, los cuales se analizaron usando un índice de similitud de comunidades de Jaccard y un modelo nulo de co-ocurrencia y con el mismo se determinaron los factores reguladores potenciales para explicar los ensambles zooplanctónicos usando una matriz de presencia y ausencia de especies. Este modelo nulo usó la coocurrencia de especies y parte de la base que las asociaciones de especies son aleatorias. Se observó una asociación significativa entre número de especies y superficie. Los resultados obtenidos indican la ausencia de factores reguladores en la mayoría de los análisis, lo que se debería a que los sitios 4 )
The lakes studied (Chapo, Sargazo, Chaiquenes and Triángulo) are located in the Alerce Andino National Park (41°30'S, 71°32'W), Chile. An inventory of the aquatic and riparian species was performed between December 2010 and January 2011. A null model analysis was done to determine the existence of regulatory factors of species associations, and the Jaccard index was applied to determine floristic similarities. It identidied 23 species, the high number was reported (14) and the most introduced species number (4) were reported at Sargazo lake, whereas the low species number was observed in Triángulo lake with three species. The analysis of the null model revealed the presence of regulatory factors in one of the three simulations. However, in the other two simulations, the species associations appeared to be random, presumably because many species were repeated at the study sites. According to the Jaccard index, Triángulo Lake is noticeably different from the other lakes, probably due to its marked oligotrophy.
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