Ambrosia artemisiifolia L. an invasive weed from ruderal areas to disturbed grasslands

Abstract

Common ragweed (Ambrosia artemisiifolia L.) is mentioned in literature as invasive weed that is commonly found in disturbed sites as roadsides, railways, gravel pits, construction sites, agricultural land, waterways etc. The greater incidence of this species in Romania is in the western counties (Timis, Arad and Bihor). In this work is presented a case study of 7 grasslands invaded with common ragweed from Valea lui Mihai (Bihor County). The dominant relief formations in the studied area are continental sand dunes, the studied being placed between the dunes. The data were collected during 2007 – 2009 period. A. artemisiifolia has an important participation in the studied grassland, being codominant in 3 grasslands from all 7 studied in this work, and having an important contribution in the other 4. This species has a participation comprised between 9.17% and 18.33% in the vegetation cover. Common ragweed abundance determinates the decrease of the mean species number, other species number, diversity index and pastoral value in the studied area.