Aquatic Plant Diversity in Italy: Distribution, Drivers and Strategic Conservation Actions

Abstract

Italy is recognized as one of the prominent hot spot areas for plant diversity at regional and global scale, hosting a rich range of ecosystems and habitat types. This is especially true considering aquatic habitats, which represent a major portion of the total water surfaces in the Mediterranean region. Nevertheless, only a scant attention was paid to clarify the species richness of aquatic plant and its contribution to the total diversity at the country scale, despite such plants are seriously threatened at multiple scales. This paper provided the first comprehensive inventory of aquatic plants at the whole country scale, collecting data on species’ distribution, trends, and explanatory determinants of species richness. We confirmed the key contribution of Italy to the regional and global aquatic plant diversity with a total of 279 species recorded since 2005, equal to the 88.5%, 55.9% and ∼10% of the richness estimated at European/Mediterranean, Palearctic and global scale, respectively. Ten species are considered extinct in the wild [among which Aldrovanda vesiculosa L., Caldesia parnassifolia (Bassi ex L.) Parl., Helosciadium repens (Jacq.) W.J.D. Koch, and Pilularia globulifera L.], four were doubt [among which Luronium natans (L.) Raf., Utricularia intermedia Hayne, and U. ochroleuca R.W. Hartman.], and eight were erroneously reported in the past, among which Isoëtes lacustris L., Myosotis rehsteineri Wartm., and Ranunculus aquatilis L. Only 18 species – mainly helophytes (14) – were present in all the 20 Italian regions, whereas hydrophytes showed most scanty regional frequencies. Temperature, latitude, area and water resources availability are the main drivers of aquatic plant spatial arrangement and diversity. Furthermore, the number of inhabitants per km2 well described the number of “lost species” since 2000. The findings of the present survey call for an urgent elaboration of large-scale strategies to ensure the survival of aquatic plants, stressing on multiple functions played by aquatic plants in supporting national economy and human well-being. In this context, Italy can play a fundamental role guaranteeing temporary refuge for projected or expected species migrations along latitude and longitude gradients. Besides, in hyper-exploited landscapes man-made water bodies can further enhance the achievement of minimum conservation targets.

Spatiotemporal Dynamics of Submerged Aquatic Vegetation in a Deep Lake from Sentinel-2 Data

“…Most of the aquatic ecosystems worldwide have been affected by dramatic perturbations over the last two centuries, and macrophytes are among the most threatened biotic component [6,7]. Furthermore, an increasing awareness of the role of global warming in driving macrophyte growth patterns has emerged in the last decades.…”

Environmental drivers of plant assemblages: are there differences between palustrine and lacustrine wetlands? A case study from the northern Apennines (Italy)

“…However, alien species tend to occur in low altitude wetlands (below 500 m a.s.l.) where human pressure is more intense and anthropogenic habitats prevail (Angiolini et al, 2013;Bolpagni et al, 2018). At higher altitudes, the reduction in number and size of anthropogenic habitats, along with low connectivity between neighboring sites, presumably restricts the spread of invasive plants due to the remoteness of these wetlands from alien sources (Becker et al, 2005;Chytr y et al, 2008b).…”

“…Considering the wide distribution of aquatic plants compared with those of terrestrial ecosystems, and since wetland vegetation is azonal, altitude has been considered a non-typical driver of floristic composition in mountain wetlands (Santamaría, 2002;Chambers et al, 2008). However, altitude necessarily includes other gradients (climatic, water quality and availability, human disturbance, vegetation heterogeneity) that influence aquatic and helophytic plants (Naqinezhad et al, 2009;Short et al, 2016;Bolpagni et al, 2018). This in turn may indirectly affect the distribution of wetland plant species (see Kamrani et al, 2011).…”

“…There was a clear distinction in the distribution of aquatic plants between wetland subsystems. Three hydrophytes with a wide distribution in Italy (Bolpagni et al, 2018), were found to be exclusive to the lacustrine habitat, due to the presence of clearings and because they are obligate aquatic plants that do not tolerate long periods of drought. Phragmites australis is also linked to lacustrine wetlands, mainly forming aquatic reed beds consisting of one or few species.…”

“…The significance of regional and local ecological drivers of biodiversity in these habitats has been highlighted as well (De Meester et al, 2005). Two major drivers of community structure in small wetlands are the hydro-period gradient and the availability of water (De Meester et al, 2005 and references therein;Bolpagni et al, 2018). These aspects may become critical under thermal and rainfall anomalies (Bolpagni et al, 2018 and references therein).…”