Elaeagnus angustifolia INVADED MIDVALLEY, RÍO NEGRO, ARGENTINA. DOCUMENTED HISTORY:

1. Elaeagnus angustifolia INVADED MIDVALLEY, RÍO NEGRO, ARGENTINA. DOCUMENTED HISTORY: FROM UNKNOWN TO WEED AND NOW… FODDER RESOURCE? Klich María Guadalupe, Fernandez Osvaldo Alberto guadalupeklich@gmail.com - http://mgklich.wordpress.com/Elaeagnus angustifolia UNRN UNS Escuela de Veterinaria y Producción Agroindustrial, Universidad Nacional de Río Negro. Choele Choel, 8360. Río Negro. ARGENTINA ofernan@criba.edu.ar Departamento de Agronomía y CERZOS, Universidad Nacional del Sur, 8000 Bahía Blanca, Buenos Aires. ARGENTINA The valleys known as High, Middle and Lower concentrate the most productive agricultural and cattle raising regions of Rio Negro province (Argentina). High, and Lower Valley have developed as agricultural zones but in the Mid Valley, excepting some intensively cultured zones, the lands are used for cattle breeding, and their natural grass vegetation constitute an important supply for bovine feeding, specially during summer time (39° 30’ S;  65° 30’ W). Elaeagnus angustifolia L. (Russian olive) was introduced as an ornamental tree to the High Valley, but escaped cultivation and actually has become naturalized along all watercourses in the Río Negro valleys. When the first plants appeared on the river margins in Mid Valley (circa 1970), as nobody knew the species, no control methods were applied. The ecological conditions of the region and human unconscious participation, allowed the species to spread. 2010 1945 1970 Initial hydrochore dispersal is surely the way the first seeds arrived to Mid Valley because of the hydrologic characteristics of the Río Negro, the occasional flooding, and of the species fruit buoyancy capacity resulting from the presence of an aerenchyma and a pubescent cover. Seed dispersal and root buds development After disturbing factors E. angustifolia regenerated by root or shoot buds activation. The species spread so that in some areas it replaced the previously existing woody plants. Since 1990 land owners considered E. angustifolia as a weed because of the decrease in extensive cattle production resulted from the reduction of herbage offer due to shadowing by the high density of branches and leaves of the bush. The dense branching was also an undesirable characteristic because of difficulties in livestock management. As those were years favored with annual precipitations higher than the average, the summer bovine grassing use of valley land was below the grass offer and animals only browsed slightly the branches of E. angustifolia. Actually, after a four years long severe drought, E. angustifolia became an important animal fodder alternative and we began the study of its nutritional grassing quality. . Klich M.G.; Weberling F; Fernández, Osvaldo A. XVII Congreso de la Asociación Latinoamericana de Malezas. I Cong. Iberoamericano de Ciencia de las Malezas., Varadero, Cuba. 2005 . Klich, M. G., Fernández O. A.. Weberling, F. XXI International Grassland Congress VIII International Rangeland Congress., Hohhot, China.: Actas Vol. II: 806. 2008 . Klich, M.G. Fernandez O.A. X Congreso Lationoamericano de Botánica, La Serena. Chile, Octubre, 2010 . Klich, M.G. 2000 Leaf Variations in Elaeagnus angustifolia related to environmental heterogeneity. Environmental and Experimantal Botany 44 : 171-183 . Klich, M.G. Tesis Doctoral. Estrategias Ecológicas de Elaeagnus angustifolia. 2005- UNS- Argentina Thank you Focko! (Dr.Focko Weberling (1926-2009)