Research Article |
Corresponding author: Gianmaria Bonari ( gianmaria.bonari@gmail.com ) Academic editor: Lorenzo Peruzzi
© 2019 Silvia Cannucci, Claudia Angiolini, Barbara Anselmi, Enrico Banfi, Marco Biagioli, Paolo Castagnini, Tiberio Fiaschi, Bruno Foggi, Antonio Gabellini, Lorenzo Lastrucci, Edda Lattanzi, Anna Scoppola, Federico Selvi, Daniele Viciani, Gianmaria Bonari.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Cannucci S, Angiolini C , Anselmi B, Banfi E, Biagioli M, Castagnini P, Centi C, Fiaschi T, Foggi B, Gabellini A, Lastrucci L, Lattanzi E, Scoppola A, Selvi F, Viciani D, Bonari G (2019) Contribution to the knowledge of the vascular flora of Miniera di Murlo area (southern Tuscany, Italy). Italian Botanist 7: 51-67. https://doi.org/10.3897/italianbotanist.7.33763
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This work aims to increase the floristic knowledge of southern Tuscany by means of a floristic investigation which took place in the Miniera di Murlo (southern Tuscany, Italy). The study area, located in the province of Siena, has an extension of 2.26 km2 and hosts a heterogeneity of habitats like rocky outcrops, woodlands, meadows and riparian formations. The prevalent geological type is an acidic sedimentary rock known as diaspri formation (jasper). The checklist of vascular flora consists of 501 taxa and includes six endemics and 13 alien species, among which Vitis labrusca is a newly-found species for the Province of Siena along with the native Rosa balsamica and Rosa squarrosa. The most interesting species, such as Anthoxanthum aristatum, Gagea bohemica, Paragymnopteris marantae, Saxifraga granulata, and Teesdalia coronopifolia, are found on acidic rocks. Species of the Italian Red List, such as Ruscus aculeatus, and species of Regional conservation interest, such as Centaurea aplolepa subsp. carueliana, Ervilia loiseleurii, and Vicia nigricans, were recorded. The chorological spectrum reveals a dominance of Mediterranean species indicating warm climate conditions and mild winters whereas the life-form spectrum shows a slight dominance of hemicryptophytes followed by therophytes. However, a clear dominance of one life-form type over the other is lacking, since the acidic and dry rocky substrate partially compensates for the humidity provided by the stream. This study highlights the relevant floristic value of the Miniera di Murlo area and supports the possible creation of a protected area or its inclusion in the adjacent one.
Central Italy, flora, floristic research, jasper, conservation, rare species, Italy, vascular plants
Tuscany is a part of the Italian territory where discrepancies in floristic knowledge are recognized; it, therefore, represents a suitable area to carry out studies on plant diversity (
This study involves an area in the surroundings of the Miniera di Murlo village in the Province of Siena (southern Tuscany, Italy). The bedrock consists of sedimentary rocks entirely made by silica, representing a sort of “geological island” occurring in an area with a completely different geological type. This edaphic condition primarily led us to the selection of Miniera di Murlo as an interesting area to investigate. According to preliminary floristic surveys, the Miniera di Murlo area could belong to those areas of high biodiversity value not included in any nature reserve. In Italy, unsuitable conservation of plant diversity hotspots may occur (
Current floristic knowledge of Miniera di Murlo is based on previous research by
Accordingly, the aim of this work was to compile a checklist of vascular plants of the Miniera di Murlo area and to analyse its ecological attributes.
The study was carried out in an area extending for 2.26 km2 that includes the jasper outcrops near the Miniera di Murlo village (Siena) in southern Tuscany (43.140713N, 11.383862E; Fig.
The main geological outcrop in the investigated area is the diaspri formation (jasper), a sedimentary late-Jurassic formation belonging to the Ophiolitic Unit of the Ligurian Domain. The diaspri formation (Suppl. material
Jasper of the Ophiolitic Unit makes a basal contact with serpentine, basalt, and gabbro (igneous and metamorphic rocks from the oceanic crust) and an upper one with siliceous limestone, shale, and marl (
Climatic data were retrieved from the Hydrological Tuscan Service (SIR; http://www.sir.toscana.it) of Monteroni d’Arbia (43.229343N; 11.422277E, 165 m a.s.l.) located at 12.4 km from Miniera di Murlo. The climate is typical of Tuscan hill valleys, more continental compared to sites at higher altitudes in the same area. As evidenced by
Data for the period 2012–2017 showed an average annual temperature of 13.8 °C. The hottest months are July (average temperature 22.9 °C) and August (average temperature 23.2 °C), the coldest are January and February with an average temperature of 5.7 °C. The average annual rainfall is 871.3 mm with maximum values in October (138.8 mm) and November (125.6 mm), although in 2015 the month with maximum rainfall was August (278.4 mm). The thermopluviometric diagram (Suppl. material
The study area is characterised by different vegetation types typical of the Mediterranean area. Arid and acidic substrates with low fertility, such as jasper, promote the growth of Mediterranean evergreen sclerophyllous species, with a medium-high Quercus ilex cover and a relative abundance of shrubs, such as Arbutus unedo, Erica arborea, E. scoparia, and Phillyrea latifolia. The herb layer under this (semi-)closed canopy of evergreen woody species is strongly shaded and relatively poor in species. A less widespread forest type with different oak species (Quercus cerris, Q. pubescens and sparse Q. suber) also occurs. In addition, the study area presents scrublands with Calluna vulgaris, Cytisus spp., Pyracantha coccinea, and Spartium junceum, mostly located along wood edges, indicating the connection between the forest and a habitat with less developed soils.
Riparian vegetation along the stream is dominated by S. eleagnos, S. purpurea subsp. purpurea, and Populus nigra subsp. nigra. Typical grassland vegetation with graminoids is also present. However, the most interesting vegetation type of the area is linked to the presence of jasper outcrops (Suppl. material
The floristic field surveys were carried out in 2017–2018. Plants collected in the field were dried in order to prepare herbarium specimens and were subsequently identified in the laboratory. The collected data were integrated with those from previous studies (
The checklist consists of 501 taxa, distributed in 294 genera and 67 families (Suppl. material
Alien species found at Miniera di Murlo (Siena). The status and associated code in the study area, in Tuscany and in Italy for alien species follow
Alien species | Status in the study area | Status in Tuscany | Status in Italy |
---|---|---|---|
Bidens frondosa | INV | P A NAT | N INV |
Erigeron bonariensis | NAT | P A INV | N INV |
Erigeron sumatrensis | NAT | P A INV | N INV |
Euphorbia humifusa | NAT | P A NAT | N NAT |
Helianthus tuberosus | CAS | P A INV | N INV |
Malus domestica | CAS | P A CAS | A NAT FER |
Opuntia engelmannii | INV | P A NAT | N NAT |
Robinia pseudoacacia | NAT | P A INV | N INV |
Setaria italica subsp. pycnocoma | NAT | P A NAT | N NAT FER |
Setaria italica subsp. viridis | NAT | P A NAT | N NAT FER |
Vitis labrusca | CAS | P A CAS | N NAT FER |
Veronica persica | NAT | P A INV | N INV |
Xanthium italicum | INV | P A NAT | T N INV |
The biological spectrum (Fig.
Life-form spectrum of species found at Miniera di Murlo (Siena). The spectrum shows the categories that appear more than five times in the checklist. A Life forms of all species found in the study area B Life forms of species occurring on jasper bedrock only. Categories are according to
The jasper flora shows higher proportions of hemicryptophytes (H: 40.2%), chamaephytes (Ch: 7.2%), and nanophanerophytes (NP: 3.3%) versus a decrease of therophytes (Th: 32%) and geophytes (G: 8.3%); the percentage of phanerophytes does not change (Ph: 9%) (Fig.
Regarding chorological types (Fig.
Distribution of Italian endemic taxa according to
Italian endemics | Status | Distribution |
---|---|---|
Centaurea aplolepa subsp. carueliana | LC | PIE; LIG; TOS |
Vicia ochroleuca subsp. ochroleuca | LC | TOS; CAM; BAS; CAL; SIC |
Polygala flavescens subsp. flavescens | DD | EMR; TOS; MAR; UMB; LAZ; ABR; MOL; CAM; PUG; BAS |
Helleborus viridis subsp. bocconei | LC | EMR; TOS; MAR; UMB; LAZ; ABR; MOL; CAM; BAS; CAL; SIC |
Digitalis micrantha | (DD*) | EMR; TOS; MAR; UMB; LAZ; ABR; MOL; CAM; PUG; BAS; CAL |
Linaria purpurea | LC | EMR; TOS; MAR; UMB; LAZ; ABR; MOL; CAM; PUG; BAS; CAL; SIC |
Chorological spectrum of species found at Miniera di Murlo (Siena). The spectrum shows the categories that appear more than five times in the checklist A Life forms of all species found in the study area B Life forms of species occurring on jasper bedrock only. Categories are according to
The jasper chorological spectrum (Fig.
The checklist includes many species related to the physical and chemical features of the substrate. Low levels of nutrients, especially nitrates, are highlighted by numerous Fabaceae (
Among the alien species, Bidens frondosa and Opuntia engelmannii are those with the most worrying alien status (sensu
The life-form spectrum shows the clear predominance of hemicryptophytes and therophytes. The H/Th ratio, indicator of the Mediterranean (values <1) or continental (values >1) nature of the flora (
In comparison with the life-form spectrum of the general flora, the one relating to plant species growing on jasper bedrock reveals a prevalence of hemicryptophytes followed by a lower percentage of therophytes. The decrease in therophytes, short-cycle plants favoured by open and disturbed environments (
The flora of the jasper substrate shows an increase of chamaephytes compared to the percentage of the general flora. This shows that soils derived from jasper bedrock promote the growth of drought-tolerant species. Rocky substrates, although with different chemistry, lead to the development of selective vegetation types and associated plants. This is evident when the life-form spectrum of Miniera di Murlo is compared with that of Tuscan serpentine floras, showing only small differences (
The analysis of the chorological spectrum reveals a prevalence of Mediterranean species that indicate warm conditions and mild winters (
The chorological spectrum of plant species growing on jasper reveals a prevalence of Mediterranean species and an increase of Eurasiatic ones. This suggests that soils on jasper bedrock keep promoting the growth of Mediterranean species while improving the growth of species typical of the Euro-Siberian region, showing an equilibrium between Mediterranean and Euro-Siberian species.
This work contributes to the knowledge of the vascular flora of a poorly researched area of southern Tuscany. Our results showed that the Miniera di Murlo area represents a hotspot for vascular plants, mainly due to the presence of a peculiar bedrock: the jasper. Despite the past presence of mines and its exploitation, the area hosts some rare species that support its inclusion in a new Special Area of Conservation, or within the current Basso Merse SAC or Nature Reserve. Active management projects or the inclusion of the Miniera di Murlo area inside a nature reserve would help to limit the spread of alien species and to better preserve the native ones.
This work has highlighted how gaps in floristic knowledge can lead to incorrect delimitation of protected areas, causing the exclusion of relevant sites with particular habitats, such as jasper outcrops. It is important to promote awareness in public administrations regarding the potential of floristic investigations as a fundamental and decisive tool to support the establishment of protected areas.
We are grateful to the participants of the annual excursion of the Tuscan Section of the Società Botanica Italiana (S.B.I.) held in this area on May 31st 2017, to Elisa Mammoliti for revising the geology paragraph and to Daniel Gerrard for English language revision. We thank Francesco Roma-Marzio and Riccardo Guarino for their helpful remarks.
Checklist of the vascular flora of the Miniere di Murlo area (Siena, Italy)
Data type: floristic inventory