Succession of ground-dwelling beetle assemblages after fire in three habitat types in the Andean forest of NW Patagonia, Argentina.

Wildfires are one of the major disturbances in the dynamics of forests and shrublands. However, little is known about their effects on insect communities that contribute to faunal biodiversity and play key roles in the ecosystem's dynamics. An intense and widespread fire occurred in 1999 in the Nahuel Huapi National Park in the Andean forest in northern Patagonia, Argentina. This fire affected adjacent, but different, habitat types. After the fire, beetle abundance, species richness and assemblage composition were compared among three habitats that were structurally different before the fire. These habitats were: 1) evergreen forest dominated by Nothofagus dombeyi (Mirb.) Oerst. (Fagales: Nothofagaceae), 2) a mixed forest of the evergreen conifer Austrocedrus chilensis (D. Don) Pic. Serm. and Bizzarri (Pinales: Cupressaceae) and N. dombeyi and 3) a shrubland with a diverse community of shrub species. The relationship between beetle diversity and vegetation structure was investigated over three consecutive years. Ground beetles were collected by pitfall traps, and plant species richness, vegetation cover, and height were measured. Beetle communities varied more over years between habitats during the early regeneration after fire. There was a shift in beetle assemblage composition with time after the fire in all habitat types, probably due to similar colonization rates and microclimatic conditions. Therefore, beetle succession was more influenced by recolonization and survivorship, accompanied by climatic conditions and recovery rate of plant communities over time, than it was influenced by pre-fire habitat conditions. These results suggest that in NW Patagonia, wildfire can have a substantial, short-term impact on beetle abundance and species composition. The pre-fire conditions of each habitat type determined the structure of post-fire communities of plants but not beetle assemblages. Wildfires produce simplification and homogenization of habitat types, and this was reflected by beetle diversity.

Hierbas como una fuente para consumo humano: una comparación entre América Latina de zona tropical y templada / Weeds as a source for human consumption: a comparison between tropical and temperate Latin America

Weeds abound in urban and agricultural environments. Depending on region and site, up to 66 per cent of weed species are edible, and may constitute and additional food source for humans. Based on 400 samples, 1/4m2 each, collected in tropical areas (e.g., roadsides, urban vacant lost, streets, sugar cane and coffee plantations in Coatepec, Mexico), average figures of edible fresh biomass vary between 1277 and 3582 kg/ha. A similar survey performed in a temperate area (739 samples in Bariloche, Argentina) showed mean values between 287 and 2939 kg/ha. A total of 43 species were sampled in Coatepec and 32 species in Bariloche. The general means were 2.1 and 1.3 tons/ha, respectively. At a greater geographic scale, a comparison between Mexican and Argentine weeds shows that, proportionately, the food parts vary a little between regions. In general, from higher to lower, the order of uses goes from leaves, seeds, roots, fruits, herbals, flowers and condiments. Edible roots (including bulbs and rhizomes) appear to be more common among perennials than among annuals. Keys words: Argentina, Bariloche, Coatepec, edible weeds, food plants, gathering, Mexico, Patagonia, urban flora