The impacts of invasive species are among the greatest threats to the persistence of native species and communities. In particular, biological invasions are more destructive when occurring in nature reserves where vulnerable species are generally found. Recent field investigations showed a significant presence of the alien plant Pennisetum setaceum in the mouth of the Simeto river, one of the main Sicilian watercourses, located 12 km south of Catania. Nature reserve since 1984, this estuary provides habitats for numerous plant and animal species, and is an important stopping place for migratory avifauna. The last floristic survey was conducted in 1988 and no alien spread was reported. Over the last two decades, P. setaceum colonized the river embankments, however, without spreading over the flood bed where, in turn, halophilous native vegetation is dominant. The aims of this study were (1) to investigate the ecological factors which favored the spread of P. setaceum; (2) to identify management flaws; (3) to propose guidelines to enhance the ecological integrity of the study area. Habitat alteration was excluded as the main driver of the P. setaceum spread because this alien plant was found in the “A” zone of the reserve where all human activities are strictly regulated. Further investigations showed that the soil content played an important role in the alien spread: P. setaceum colonized only the embankments where soil nutrient levels were high without invading the flood bed because of a much higher gradient of salinity. This result implied that the most vulnerable zones to further alien spread are those rich in soil nutrient whereas the areas with high saline content seemed relatively immune to P. setaceum. Enforcement of conservation laws, effective management strategies and regular biomonitoring are thus recommended to stop timely the spread of alien species.
|Titolo:||Spread of the plant invader Pennisetum setaceum in a protected wetland of Sicily|
|Data di pubblicazione:||2011|
|Appare nelle tipologie:||4.3 Poster|