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.

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.

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.