Some 50 years ago the first two cases of naturalization of Pennisetum setaceum (Forssk.) Chiov. were recorded at Catania and Palermo. After a short residence time, this paleotropical plant begun to spread faster and faster, so that nowadays urgent intervention policies are needed in order to face its huge impact both on local pre-forest communities (degraded maquis and garrigues) and on annual and perennial grasslands. After providing an overview on the behaviour of this xenophyte, we exam-ined its spreading process in Sicily and we compared the width of its ecological range with that of the two Poaceae dominating the perennial grasslands which are the most prone to its invasion, i.e. Ampelodesmos mauritanicus (Poir.) Dur. et Schinz and Hyparrhenia hirta (L.) Stapf. Supported by floristic-vegetational relevées, this study allowed to 1) trace the steps of P. setaceum spreading and to point out the recent acceleration of this process; 2) evaluate if and to which extent P. setaceum inter-acts with A. mauritanicus and H. hirta and influences the composition and the structure of local xeric grasslands; 3) forecast the possibile trend of its diffusion within regional territory. Still much effort ought to be done to assess the effect of P. setaceum on local phytodiversity and its invasion ability: in fact, a more effective monitoring net should be created, focusing the future investigations on those aspects which seem to have played a major role for its success worldwide, such as: 1) influence of micro- and mesoclimate on its life-cycle; 2) reproductive features (e.g. vector and speed of dispersal, role of soil seed bank); 3) photosynthetic efficiency; 4) allelopathy and metabolite allocation mecha-nisms; 5) disturbance frequency and intensity; 6) sociability. Finally, we underline the need to combine monitoring activities with the active control of affirmed populations and the systematic eradication of any new metapopolation to avoid a real catastrophe affecting the coastal ecosystems of our island.
|Numero di pagine||18|
|Stato di pubblicazione||Published - 2010|