Effect of normal and elevated CO2 levels on the growth of some invasive weeds in Turkey.
Climatic changes can severely impact the biological and physical components of our earth. Invasive species are considered a threat to native species owing to their competitiveness. The changing climate particularly the increasing CO2 levels in the atmosphere can increase the proliferation of invasive weeds. The information regarding the response of invasive weeds to increasing CO2 levels will be useful for formulating the management plans for these species. We supposed that the increasing atmospheric CO2 can improve growth of invasive weeds in Turkey. The effect of normal (400 ppm) and elevated CO2 (800 ppm) levels was evaluated on the growth and dry matter accumulation of some important invasive weeds in Turkey. The invasive species tested included Avena barbata, Bromus tectorum, Capsella bursa-pastoris, Poa bulbosa, and Carduus nutans. These invasive weeds were grown under normal and elevated CO2 in a controlled environment glasshouse and the data regarding the plant height, chlorophyll, fresh weight, dry weight and number of leaves per plant was recorded. The results indicated that C. nutans and P. bulbosa were not affected by increased CO2 levels in terms of plant height, chlorophyll, fresh weight, dry weight and number of leaves. C. bursa-pastoris was negatively affected by the increased CO2 levels having lower height, fresh and dry weight at higher CO2. A. barbat and B. tectorum were positively influenced by the increased CO2 level. A significant increase in the dry matter accumulation of both weeds was recorded when grown under the elevated CO2 levels. In conclusion, the invasive species will respond variably to the changing climate. Hence, some of these will not be affected, the others will have negative effects on their growth, and some will increase their growth in response to changing climate. The information is important for managing the invasive weed species under the scenario of changing climate, especially the increasing CO2 levels in the atmosphere.