APPROACHES ON THE INVASIVE ALIEN TAXA IN ROMANIA - AMBROSIA ARTEMISIIFOLIA (RAGWEED) II

In a previous paper we presented the localities in Romania where we identified populations of Ambrosia artemisiifolia. Between 2008-2011, investigations were continuing. Our data clearly show that Ambrosia is present throughout the country. The territories heavily infested are railway embankments, along traffic routes, gravel pits, building sites, forest edges, industrial areas, cemeteries and recreational areas. It is quite common to find ragweed in many private gardens, or flower pots in urban areas. The few foci observed along riversides got there by household waste and construction waste. In many rural communities find it on the drainage ditches. Disturbed and neglected land (on city limits and outside the city), abandonment of land without subsequent turning of stubble and another wrong agricultural practice, absence of ruderal weed control are the main causes that favor the dissemination of our country. Intensity of anthropogenic influence is manifested mainly by transport of materials and soil movement during road rehabilitation and construction of highways. The recent observations show that could be expected to appear on agricultural fields, now being found only on the outskirts of cultivated land, at 5-6 meters from high traffic roads. Ambrosia benefits from human activities to spread. This implies a strong control strategy. The main objective of the fighting activities need to be to reduce damages caused by its pollen and to limit its expansion. If invasion by Ambrosia is left uncontrolled, increase of allergies could heavily augment the treatments. Knowledge about mechanical or chemical control of ragweed could be very important for road and rail services, agricultural institutions, farmers, staff responsible for managing natural areas, institutions that approves and oversees residential sites and factories, responsible personnel of the administrations from cities and rural localities. Reducing the population is more required than simply reducing its biomass. Individual measures often do not solve the real problem. In Timisoara, the fight against such a quarantine organism became in fact obligatory by administrative decision in 2007. A. artemisiifolia has been fought by grubbing and repeated cutting (in parks, along the main roads). This taxa respond to the cutting by producing more secondary branches. Under these conditions we determined and compared several eco-physiological parameters. SLA and SLW are good indicators of leaf toughness. LWL is useful measure of the physiological water status of plants. Leaves of Ambrosia are highly plastic