Corresponding author: Emanuele Fanfarillo (
Academic editor: L. Peruzzi
Wetlands are among the most fragile habitats on Earth and have often undergone major environmental changes. As a study case in this context, the present work aims at increasing the floristic knowledge of a reclaimed land now turned into an agricultural lowland with scarce patches of natural habitats. The study area is named Piana di Rosia, and it is located in southern Tuscany (Italy). The compiled checklist consists of 451 specific and subspecific taxa of vascular plants. The life-form spectrum shows a predominance of hemicryptophytes, followed by therophytes. The chorological spectrum highlights a co-dominance of Euri-Mediterranean and Eurasian species along with many widely distributed species. The checklist includes seven species of conservation concern, three Italian endemics (
Bonari G, Fiaschi T, Fanfarillo E, Roma-Marzio F, Sarmati S, Banfi E, Biagioli M, Zerbe S, Angiolini C (2021) Remnants of naturalness in a reclaimed land of central Italy. Italian Botanist 11: 9–30.
Wetlands are acknowledged to be among the most biologically productive ecosystems (
In the Mediterranean Basin, natural wetland habitats decreased in extension by 10% between 1975 and 2005 (
In Europe, the loss of wetland biodiversity is a consequence of the declining extent and quality of wetland habitats (
This study concerns a lowland known as Piana di Rosia, located a few kilometers southwest of Siena (Tuscany, central Italy). This former wetland turned into an intensive agricultural area in the 19th century. Though, land-use change and human impact led to a substantial loss of the humid habitats, relict elements of naturalness, related to more or less humid environments, are present.
In Tuscany, information at the species level is usually easily available as it is embedded in floristic online databases (i.e., Wikiplantbase #Toscana –
The Piana di Rosia is a lowland plain of central Italy that covers 23.23 km2 and is located about 10 km southwest of Siena (southern Tuscany,
The study area borders the Special Area of Conservation (
Borders of the study area (red dashed line) and, in the box, the location of the Piana di Rosia (Sovicille, Siena) in Italy.
The study area is dominated by alluvial and lake deposits. The alluvial deposits occur in the central and southern part and have a mainly gravelly and/or sandy texture. Lake sediments occur along the borders of the study area, at slightly higher elevations. In the eastern part, eluvian-colluvial deposits occur. In the northeastern part, where superficial deposits are missing, marine Pliocene deposits emerge (mudstones and sandstones). An outcrop of Miocene continental breccia (limestone) is present near the village of Malignano (
The bioclimate of the study area can be classified as Oceanic sub-Mediterranean (Temperate sub-Mediterranean macrobioclimate). The thermotype is lower mesotemperate and the ombrotype is upper sub-humid. Regarding the continentality, the climate is weakly semi-continental (
The Piana di Rosia was formerly an ancient wetland reclaimed in the 19th century for agricultural purposes. The plain was neither included in the existing inventory of the marshy areas of Tuscany (
Aerial photos of the study area in 1954 (
The main land-use types in the study area derive from thematic maps of
We carried out floristic surveys from 2017 to 2019 in all the land-use types, but excluding urban and industrial areas, with the exception of the airport area, that are limited in extension and out of our aim. The investigations were performed in all seasons. The collected specimens are stored in the herbarium SIENA (acronym follows
To highlight chorological novelties, we checked species distribution at the administrative province, region and national levels (
Finally, we calculated a Species-Area Relationship (
Graphs were drawn using R Studio v. 3.6.0 (
The floristic checklist includes 451 specific and subspecific taxa for the study area (Suppl. material
According to the
Representation of the families across the inventoried flora. Each rectangle represents a family. The area of each polygon is proportional to the number of taxa present in the given category. Other families = families with less than 12 species; Caryoph. =
Overall, we found seven species of conservation concern. One species (
We found 10 native taxa that are new or confirmed for the administrative province of Siena:
We found 16 rare native taxa that represent the second or third recent record in the administrative province of Siena. They are
Of the 41 alien species, 30 are neophytes and 11 are archaeophytes. Neophytes are
We found 21 segetal taxa in the study area. Among the segetal species, four are strictly segetal, i.e., strictly related to wheat fields and similar habitats, and they are
Eleven aquatic vascular plant species were recorded, including five helophytes and six hydrophytes. The helophytes are
The life-form spectrum shows a predominance of herbaceous taxa, mostly hemicryptophytes (35.9%) and therophytes (30.8%) (Fig.
The chorological spectrum shows a co-dominance Mediterranean (27.1%) and Eurasian (23.5%) elements (Fig.
Life-form spectrum of the inventoried flora. Ch = chamaephytes; G = geophytes; H = hemicryptophytes; Hy = hydrophytes; NP = nanophanerophytes; Ph = phanerophytes; T = therophytes. The area of each polygon is proportional to the number of taxa present in the given category.
Chorological spectrum of the inventoried flora. Atl. = Atlantic; E. = Italian endemics; Euri-Medit. = Euri-Mediterranean; Europ. = European; Oro. = Orophilous; Steno-Medit. = Steno-Mediterranean. The area of each polygon is proportional to the number of taxa present in the given category.
We studied a reclaimed land of central Italy that is currently an agricultural area. Our floristic surveys revealed the presence of a relatively rich vascular flora in the study area, thanks to the diversity of the habitats present, although most of them occur as small patches. In particular, wetlands and relict woods represent the most relevant elements. Therefore, our results suggest that, despite the conversion to agricultural land, former wetlands host particular species, especially in particular remnant habitats.
The abundance of
The high proportion of annual species, mostly linked to non-hygrophilous communities as found by
The chorological spectrum is in line with the life-form spectrum, highlighting a transition between the Mediterranean and Temperate climate. Both, European and Mediterranean species are abundant, with a slight predominance of the former. The high number of widely distributed species is largely due to the occurrence of synanthropic plants (e.g.,
The presence of endemics and species of conservation concern, both nationally and locally, is useful to assess the status and quality of a flora and of the environment. As mentioned, in our study area such species are very few. This is predominantly linked to the high human impact but might also be due to the lack of specific substrates, morphology or any other particular environmental features. For example, the Piana di Rosia lacks areas with outcropping rocks. This deficiency is partially compensated by the presence of dry-stone walls, boulders, dirt roads, and road edges. Here, we found characteristic species of outcrops or habitats with low soil formation, such as
The alien species we found are mostly neophytes and their amount is considerable, with every tenth species being an alien one. The local naturalization status of such taxa mostly matches their status on a regional level, except for a few species that are considered casual or naturalized in the study area, but that are naturalized or invasive in Tuscany, respectively, such as
In the study area, we found new alien species for the administrative province of Siena. Among the most invasive ones, there are
The analysis of segetal species revealed that most of the taxa are not of conservation concern in Europe, since all are common and widespread. This is consistent with the fact that agriculture in the area is mostly intensive, and thus there is a lack of the typical species-rich fields common in many traditional agricultural areas of Italy (
This work contributes to the knowledge of the vascular flora of a poorly studied area of southern Tuscany, a former wetland of the previous century. Our results suggest that the land-use changes that occurred in the Piana di Rosia have modified the typical wetland flora and caused a general simplification of the plant species present. Further, the overall number of species and the number of native species present is lower than expected, while the opposite is true for alien species. Despite this, remnants of natural or semi-natural vegetation, like residual woods and shrubs, together with the presence of natural and artificial small water bodies, allow the presence of interesting plant species occurring in relatively undisturbed habitats, such as endemics, relatively rare species, protected species, and hydrophytes. We also found some species that have not been reported in the administrative province of Siena for over a century. These features are typical of “type 2” of the High Nature Value farmlands, i.e., “farmlands with a mosaic of low intensity agriculture and natural and structural elements, such as field margins, hedgerows, stone walls, patches of woodland or scrub, small rivers etc.” (
Although this study fills a gap in the floristic knowledge of southern Tuscany, our data also suggest that the knowledge of southern Tuscany is far from complete and further botanical and ecological investigations are generally needed, also in areas with an alleged scarce environmental value. Accordingly, surveying and inventorying plant biodiversity in current agroecosystems is fundamental for what they have represented in the past, but also for a better application of sustainable management in the future, in the perspective of preserving valuable elements and restore ecosystem functioning and services (
We thank Nicola M.G. Ardenghi and Gabriele Galasso for their help in the identification of some plants, Barbara Anselmi for the help in creating the maps, Ivan Martini for revising the section about geologic aspects, Silvia Cannucci for the help during field surveys, Oretta Muzzi for her help with obtaining poorly accessible literature and the Ampugnano Airport for allowing us to enter the fenced area. We thank Fabrizio Bartolucci, Stefania Biondi and Lorenzo Peruzzi for their comments on the manuscript. G.B. was supported by the Accademia dei Fisiocritici of Siena.
Figures S1–S3 and floristic inventory
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