Construction of an ethnographical database of groups of immigrants and their descendats in the province of Buenoas Aires

In Argentina, research about immigration has traditionally been made fundamentally upon two majorities: Spanish and Italian. There were few specific anthropological studies concerning small and medium groups of immigrations (Cape Verdeans, Polish, Greek, Lithuanians, Ukrainians, etc.). As a result of our experience in the field of anthropology, working with some of these goups and their descendants, we became aware of the need of a tool which allows, in a flexible way, to recognize the profile which characterizes the studied communities and those which will be studied in the future. Our ultimate goal was to establish in advance, sufficiently representative comparisons to describe similarities and differences between distinctive groups. Without such a tool, it would be difficult to characterize the modifications which where produced and still take place as a consequence of the cultural change and the intercultural contact.At this stage of the research, diverse specialist in statistics were consulted, who agreed that a database is the best tool for this purpose, since it allows flexible and more efficient storage and management of the information. Thus, we considered two steps: 1. Definition and development of the data base structure, 2. Elaboration of an interface for actualization and modification of the collected data.Fil: Maffia, Marta Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Etnografía; ArgentinaFil: Mehltreter, Klaus. Instituto de Ecología; MéxicoFil: Basaldúa, Marcelo. Universidad Nacional de La Plata; Argentin

Construction of an ethnographical database of groups of immigrants and their descendants in the province of Buenos Aires, Argentina - excluding Spanish and Itali

In Argentina, research about immigration has traditionally been made fundamentally upon two majorities: Spanish and Italian. There were few specific anthropological studies concerning small and medium groups of immigrants. It was agreed that a database would be the best tool which would allow to recognize the profile of the studied communities and those which will be studied in the future. Polling was selected as the most convenient technique tocollect the data for the database presented in this article. The final objective o f this project is to undertake a socio-cultural survey of all groups of immigrants and their descendants (excluding Spanish and Italian), resident within the Province of Buenos Aires

Biogeographical analysis of the pteridophyte diversity of continental Argentina and Chile

Las Pteridófitas de Chile continental están representadas por 116 especies nativas (43 géneros, 20 familias), y en Argentina continental por 346 (86 géneros, 27 familias). Ambos países comparten 89 especies (41 géneros, 20 familias). La menor diversidad pteridofítica y el mayor endemismo en Chile (11,2 %) que en Argentina (3,5 %) están relacionados probablemente con extinciones históricas y su actual aislamiento geoclimático. Sin embargo, se destaca que el endemismo en los helechos es cinco a seis veces menor que en Angiospermas. Los géneros con más especies en Argentina son Thelypteris (34), Asplenium (32), Cheilanthes (21), Blechnum (19) e Hymenophyllum (16). Los dos últimos también son los más diversificados en Chile (Hymenophyllum, 18 y Blechnum, 10). En la región estudiada la diversidad muestra incrementos latitudinales opuestos, concentrándose en tres centros, dos subtropicales en el noroeste y noreste de Argentina y uno templado-lluvioso en el sur argentino-chileno alrededor de los 40º latitud sur. Los tres centros de diversidad concentran el 93 % de las especies y el 95 % de los endemismos, compartiendo pocas especies entre ellos. En los centros subtropicales las familias Aspleniaceae, Polypodiaceae, Pteridaceae, Thelypteridaceae y Selaginellaceae son sus componentes más importantes, y comparten un gran número de especies con Bolivia y Brasil, respectivamente. El centro templado sur tiene una menor diversidad pteridofítica, pero se hallan en él mayor cantidad de endemismos (77 %) que en los centros subtropicales, a consecuencia de un fuerte aislamiento. Sin embargo, presenta altos índices de similitud e intercambio florístico entre ambas vertientes de Los Andes. Allí las Blechnaceae y Hymenophyllaceae son las familias mejor representadas. Los taxa que presentan una distribución disyunta encontrándose en los tres centros de diversidad, nos indican que la pteridoflora del Cono Sur fue históricamente más extensa y continua, y que sus límites han retrocedido a causa de los impactantes cambios climáticos y geomorfológicos que sucedieron durante el Terciario y el Pleistoceno.The pteridophytes are represented by 116 native species (43 genera/20 families) in continental Chile, and by 346 native species (86 genera/27 families) in continental Argentina. Both countries share 89 species (41 genera/20 families). Lower pteridophyte diversity and the higher endemism in Chile (11.2 %) than in Argentina (3.5 %) are possibly related to historical extinctions and the actual geo-climatic isolation. However, the endemism in pteridophytes is five to six times lower than in angiosperms. The richest Argentinean genera are Thelypteris (34 species), Asplenium (32), Cheilanthes (21), Blechnum (19) and Hymenophyllum (16). The last two genera are also the most numerous in Chile (Hymenophyllum 18 species and Blechnum 10). In the two countries, pteridophyte diversity shows opposite latitudinal trends, with high species richness in three centers: two subtropical humid centers in northwestern and northeastern Argentina, and a temperate humid center in southern Chile and Argentina around 40º S. The three centers concentrate 93 % of the species and 95 % of the endemisms, sharing few species. In the subtropical centers, the families Aspleniaceae, Polypodiaceae, Pteridaceae, Thelypteridaceae and Selaginellaceae are the main components and share a large number of species with Bolivia and Brazil, respectively. The southern temperate center has a lower pteridophyte diversity, but a larger number of endemisms (77 %) than the northern subtropical centers. However, adjacent regions of Chile and Argentina within the temperate center have high similarity and maintain a strong floristic interchange. Blechnaceae and Hymenophyllaceae are the most common families. Taxa with disjunct distribution patterns and with presence in the three centers indicate that the pteridophyte flora had a wider and continuous distribution in the past, and that their limits have receded as a consequence of the strong climatic and geomorphologic changes during the Tertiary and the Pleistocene.Facultad de Ciencias Naturales y Muse

Are Nested Networks More Robust to Disturbance? A Test Using Epiphyte-Tree, Comensalistic Networks

Recent research on ecological networks suggests that mutualistic networks are more nested than antagonistic ones and, as a result, they are more robust against chains of extinctions caused by disturbances. We evaluate whether mutualistic networks are more nested than comensalistic and antagonistic networks, and whether highly nested, host-epiphyte comensalistic networks fit the prediction of high robustness against disturbance. A review of 59 networks including mutualistic, antagonistic and comensalistic relationships showed that comensalistic networks are significantly more nested than antagonistic and mutualistic networks, which did not differ between themselves. Epiphyte-host networks from old-growth forests differed from those from disturbed forest in several topological parameters based on both qualitative and quantitative matrices. Network robustness increased with network size, but the slope of this relationship varied with nestedness and connectance. Our results indicate that interaction networks show complex responses to disturbances, which influence their topology and indirectly affect their robustness against species extinctions

Pteridophyte fungal associations : current knowledge and future perspectives

Current understanding of the nature and function of fungal associations in pteridophytes is surprisingly patchy given their key evolutionary position, current research foci on other early‐branching plant clades, and major efforts at unravelling mycorrhizal evolution and the mechanisms underlying this key interaction between plants and fungi. Here we provide a critical review of current knowledge of fungal associations across pteridophytes and consider future directions making recommendations along the way. From a comprehensive survey of the literature, a confused picture emerges: suggestions that members of the Lycopsida harbour Basidiomycota fungi contrast sharply with extensive cytological and recent molecular evidence pointing to exclusively Glomeromycota and/or Mucoromycotina associations in this group. Similarly, reports of dark septate, assumingly ascomycetous, hyphae in a range of pteridophytes, advocating a mutualistic relationship, are not backed by functional evidence and the fact that the fungus invariably occupies dead host tissue points to saprotrophy and not mutualism. The best conclusion that can be reached based on current evidence is that the fungal symbionts of pteridophytes belong to the two fungal lineages Mucoromycotina and Glomeromycota. Do symbiotic fungi and host pteridophytes engage in mutually beneficial partnerships? To date, only two pioneering studies have addressed this key question demonstrating reciprocal exchange of nutrients between the sporophytes of Ophioglossum vulgatum and Osmunda regalis and their fungal symbionts. There is a pressing need for more functional investigations also extending to the gametophyte generation and coupled with in vitro isolation and resynthesis studies to unravel the effect of the fungi on their host

Leaf Phenology of the Climbing Fern Lygodium venustum in a Semideciduous Lowland Forest on the Gulf of Mexico

Volume: 96Start Page: 21End Page: 3