Monitoring of alien aquatic plants in the inland waters of Sicily (Italy)

Vincenzo Ilardi,Elisabetta Oddo,Angelo Troia

doi:10.36253/jopt-8414

Abstract

Updated and reliable data on the presence and distribution of alien aquatic plant species in Sicily are lacking, and there is a need to fill this gap for a proper and efficient management of freshwater ecosystems and biodiversity. This paper reviews the available knowledge about alien aquatic vascular plants in the inland waters of Sicily (Italy). The aim is to provide an updated checklist, as a first step in the study of the impact of those plants on the native species and ecosystems of this Mediterranean island. The paper focuses on the strictly aquatic species (hydrophytes), excluding emergent macrophytes. Four species were listed, all of them free-floating and with American origin. Most of them occur within protected areas, and their introduction in the island appears to be anthropogenic. A set of functional traits of the alien species, such as relative growth rate, leaf mass per area, nitrogen and carbon content, were screened. These traits are useful for assessing the species invasive potential compared to native ones.

Highlights

Invasive alien species pose a major global threat to the conservation of biodiversity, causing the extinction of native species and modifying ecosystem functions: this is true for aquatic habitats, susceptible to invasion due to usually high disturbance regimes affecting these habitats and the easy dispersal of water plant propagules
Nomenclatural reasons linked to the use of the name “Azolla caroliniana” created further confusion, so that the two species previously reported for Sicily (Romano et al 1994) have been considered a single species in the last national Flora (Pignatti et al 2017-2019)
Comparing the number of alien aquatic plant species reported for Sicily with the total number of alien aquatic plant species in the European and Mediterranean Plant Protection Organisation (EPPO) list (Brundu 2015) even if it does not include some of the species in our list - reveals that about 1/5 of that number have been found in Sicily, on a very limited area compared to the EPPO region currently including 50 countries

Summary

Introduction

Invasive alien species pose a major global threat to the conservation of biodiversity, causing the extinction of native species and modifying ecosystem functions: this is true for aquatic habitats, susceptible to invasion due to usually high disturbance regimes affecting these habitats and the easy dispersal of water plant propagules. Aquatic environments are difficult to monitor, and an early detection of introduction of a submerged species is seldom possible (Brundu 2015). Mediterranean islands are appreciated model systems for studying invasions due to the diversity of alien taxa, long history of species introductions and (usually) detailed floristic records (Hulme 2004; Lloret et al 2005; Bjarnason et al 2017; Chiarucci et al 2017; Pasta et al 2017). No recent and updated synthesis on the ecology and the distribution of the Sicilian alien aquatic flora is currently available

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