The deleterious influence of ‘Arundo donax’ within selected Maltese valley beds

Abstract

'A. donax' is an invader of riparian ecosystems with negative impacts upon native species and habitats in the Maltese Islands. The plant is considered archaeophytic and has become dominant in many sensitive riparian ecosystems, which are already under significant threat due to anthropogenic influence. This study was an initial assessment of the environmental factors influencing 'A. donax', within the context of the Maltese Islands. Selecting two watercourses, a number of sample sites were chosen based on the density of 'A. donax' stands. Soil pH, nitrate, potassium and water holding capacity were measured in a laboratory and, together with plant length, light intensity, and other factors, were used to make observations. 'A. donax' appears to thrive in full sunlight while suppressing other plants beneath its thick canopy. Stand density was positively correlated with soil water holding capacity, but not with nutrient levels. High level of nitrates may also be leading to anoxic conditions. Further studies into the relationship between 'A. donax' and large, shade-creating trees may shed more light on the possibility of control through competition.