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After an extensive two-year long research effort, the results document the diversity of vascular plants that grow in the public spaces of Santiago, Chile. We analyze the taxonomic composition, life-forms and phytogeographic origin of the vascular flora of Santiago and, finally, we compare the results with those of urban areas in the Northern Hemisphere. We identified 508 species, 100 families, and 338 genera. The families that showed the greatest richness were Asteraceae and Poaceae. We found that at least 85.1% of the species are exotic. The life-forms are similarly represented, although chamaephytes and geophytes are poorly represented. We conclude that the composition of the urban flora of Santiago differs from that of most Northern Hemisphere cities, due to the increased presence of exotic species, which is likely a consequence of the historical and cultural patterns of ornamentation. Therefore it is likely that this urban area would be an adverse environment for the establishment and development of native species. KEYWORDS:Central Chile, exotic plants, native plants, plant diversity, urban flora. RESUMENLos resultados documentan la diversidad de plantas vasculares que se desarrollan en el espacio público de Santiago en una investigación que se prolongó por dos años. Nosotros analizamos la composición taxonómica, la forma de vida y el origen fitogeográfico de la flora vascular y, finalmente, comparamos los resultados con aquellos de áreas urbanas del Hemisferio Norte. Se reconocen 508 especies, 100 familias y 338 géneros. Las familias que tienen mayor riqueza fueron Asteraceae y Poaceae. El 85,1% de las especies son exóticas. Las formas de vida están similarmente representadas, aunque las caméfitas y las geófitas están muy poco representadas. Concluimos que la composición de la flora urbana de Santiago se distingue de la mayoría de las ciudades del Hemisferio Norte por el mayor número de especies exóticas, que es probablemente una consecuencia de los patrones históricos y culturales de ornamentación, al tiempo que los espacios urbanos parecen representar un ambiente adverso para el establecimiento y desarrollo de especies nativas. PALABRAS CLAVE:Chile central, plantas exóticas, plantas nativas, biodiversidad de plantas, flora urbana.

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Analysis was performed of the richness and abundance of woody species, forbs, and annual grasses in the easily germinating soil seed bank (henceforth seed bank) in a mediterranean shrubland of central Chile. The effects of successional development after fire and by microsite type (underneath or outside shrubs) on the density of seeds in the soil, and the relationship of species abundance in the seed bank with its abundance in the aboveground vegetation was examined. A total of 64 plant species were recorded in the seed bank, of which 44 were annual or biannual. Eight species were woody and another eight were perennial herbs. Four could not be identified to species level. The highest richness of established herbaceous species was recorded in late spring, with 31 species. The regeneration of the herbaceous vegetation was driven by the annual production of seeds and by a reserve of shortlived propagules in the soil. Density of all germinating seeds was significantly higher during late spring and late summer. Density of grass seeds was greater during late spring, while that of all other species was greater during late summer. Annual grass seeds accumulated in higher proportion at exposed microsites rather than under woody canopy, and in young (< 5 years old) and intermediate-age patches (10-20 years old) rather than in mature vegetation (30-50 years old). The abundance of established woody and herb species was uncorrelated with that of the seed bank.

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