Analisi distributiva e studio fitosociologico delle comunità a Santolina insularis (Gennari ex Fiori) Arrigoni della Sardegna meridionale (Italia)

Information on the distribution and phytosociological study of communities with Santolina insularis (Gennari ex Fiori) Arrigoni in southern Sardinia (Italy). Santolina insularis is a polyploid endemic distributed mainly in the south and central-eastern parts of Sardinia (Italy). It is found from sea level to the summit of Mt. Gennargentu (1834 m a.s.l.). This paper provides up-to-date information on the distribution of the species and the results of phytosociological study of the communities found in southern Sardinia. Two new associations called Euphorbio cupanii-Santolinetum insularis and Thymelaeo hirsutae-Santolinetum insularis are proposed on the basis of 37 original relevés and two from the literature. The former is linked to glareicolous environments of the Iglesias area and has two subassociations which vicariate in relation to substrate rocks and their physicochemistry, as well as bioclimatic and syndynamic conditions. The second is characteristic of non-stabilised alluvial beds of the Sarrabus-Gerrei and was hitherto regarded as a variant of the association Polygono scoparii-Helichrysetum microphylli. The two associations are related syntaxonomically through the alliance Teucrion mari, which includes chamaephytic vegetation with distribution in Sardinia and Corsica, indifferent to substrate chemistry and capable of establishing on degraded soils in the initial stages of pedogenesis

The plant communities of Tuscan rice fields

Vascular plants colonizing rice fields are highly specialized to grow in such a peculiar habitat, which is at a crossroad between wetlands and arable land. Italy is one of the main rice producers in the World, and most of its rice production is concentrated in northern regions. A few descriptive studies are available about the plant communities colonizing rice fields in the area. On the contrary, nothing is known about such communities in central Italy (Tuscany), where rice cultivation has a long tradition as well. With this study, we provide the first knowledge about the plant communities growing in the rice fields of southern Tuscany, where we carried out 40 square vegetation plots of 4 m2 size in early September 2021 and 2022. The surveyed plant communities were characterized by a high presence of alien species, such as Cyperus difformis, Heteranthera reniformis, and Lindernia dubia, and were classifiable in the class Oryzetea sativae Miyawaki 1960. However, based on preliminary floristic observations and on distributional data from literature, most of such alien species seemed unable to spread outside rice fields and their immediate channels, except for the invasive plant of European concern Hydrocotyle ranunculoides. Among native species, the most frequent were Alisma plantago-aquatica, Bolboschoenus maritimus, and Cyperus fuscus. An abundant presence of Characeae algae was often recorded. The channels surrounding rice fields host natural aquatic communities with Potamogeton spp., Utricularia spp., and Najas spp., classifiable in the class Potamogetonetea Klika in Klika et Novák 1941 and representing the Natura 2000 Habitat 3260 “Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation”

The syntaxonomic position of Santolina etrusca - multivariate analysis

The results of multivariate analysis of the syntaxonomic role of Santolina etrusca (Lacaita) Marchi et D'Amato, a species endemic to Tyrrhenian central Italy, are reported. Classification was performed by polythetic divisive analysis using two-way indicator species (TWINSPAN). Ordination analysis was performed by correspondence analysis (CA). Classification and ordination showed that although Santolina etrusca grows prevalently in communities of Rosmarinetalia Br.-Bl. ex Molinier 1934, it is ecologically correlated and associated with entities of unstable nitrophilous communities subject to frequent disturbance belonging to an order, Helichryso-Santolinetalia Peinado and Martinez-Parras 1984, with western eumediterranean distribution. However it does not have a well defined sociological role, as it is constant in all community groups

A synecological study of communities with Santolina Corsica Jordan et Fourr.

Santolina Corsica is endemic to Corsica and Sardinia, with the main distributional area in central-northern Corsica. The distribution and floristic composition of the communities with S. Corsica were studied in relation to different environmental parameters such as altitude, geology and soil. The data was analysed by numerical methods: two-way indicator species (TWINSPAN) and Canonical Correspondence Analysis (CCA). TWINSPAN classification of 39 relevés revealed seven different community groups which were interpreted as belonging to a new subassociation of Stachydi-Genistetum in the alliance Teucrion mari (order Rosmarinetalia) and to Helichryso-Santolinetalia. The floristic composition of the communities studied was significantly correlated with the gradient of soil evolution. Another important factor was interpreted to be substrate coherence/inco- herence. The altitude/temperature gradient was not correlated with the floristic composition of the different communities. Several communities were regeneration stages after cultivation or grazing, and others seemed to be relatively unaffected by human activity. The ecological optimum for S. Corsica was in the former, in codominance with Helichrysum italicum

Dose-Dependent and Species-Specific Effects of Wood Distillate Addition on the Germination Performance of Threatened Arable Plants

Wood distillate (WD) is a bio-based product applied to crop plants for its known action in terms of growth promotion and yield enhancement, but studies are lacking on its effects on the germination of arable plants. To test such effects, we applied WD at six different concentrations on the diaspores of three threatened arable plants: Bromus secalinus, Centaurea cyanus, and Legousia speculum-veneris. For all the studied species, the effect of WD was dose-dependent and species-specific. In B. secalinus, the germination percentage (GP) decreased at 0.125% WD but then remained stable at higher concentrations up to 1%. At 2% WD, almost no germination was observed. Mean germination time (MGT) was not influenced up to 1% WD but significantly increased at 2% WD. The germination rate index (GRI) and germination energy (GE) remained unaffected up to 1% WD but decreased at 2% WD. In C. cyanus, WD had no effects on GP and GE at any concentration. MGT showed no difference with the control up to 1% WD, but significantly increased at 2% WD. GRI increased only at low concentrations (0.125% and 0.25%). The germination performance of L. speculum-veneris was unaffected up to 0.25% WD for all the tested parameters. From 0.5% WD, a reduction in GP, GRI, and GE and an increase in MGT were observed. At 2% WD, germination was totally blocked. Our results suggest that using WD at low concentrations (<0.5%), those commonly used in arable crops, does not affect the germination of the three investigated plant species

Summer roadside vegetation dominated by Sorghum halepense in peninsular Italy: survey and classification

Sorghum halepense is a synanthropic tall grass distributed worldwide from tropical to temperate zones, and it is often considered an invasive alien. It is a perennial, rhizomatous plant that tends to form dense stands derived from vegetative and sexual propagation. Despite roadside plant communities dominated by Sorghum halepense are very common in southern Europe, their phytosociological aspects are scarcely studied. In this work, we present the results of a vegetation survey in peninsular Italy, carried out by means of the phytosociological method. In total, we carried out 73 releves in Liguria, Tuscany, Latium, Campania, Basilicata, and Apulia. We statistically compared our releves to those from the Balkans classified in the Cynodonto-Sorghetum halepensis, an association of agricultural annual weed vegetation of the class Stellarietea mediae s.l. used in the past as a reference for Italian S. halepense-dominated communities. Our results show that the Italian communities are different from the Cynodonto-Sorghetum halepensis communities, since the latter are rich in annual species, while the former are rich in perennial species. From the syntaxonomic point of view, the Italian communities are better classified in the class Artemisietea vulgaris. We describe the new (sub-)ruderal association Potentillo reptantis-Sorghetum halepensis, including a meso-hygrophilous variant with Urtica dioica and an agricultural variant with Elymus repens. We have evidence that the Potentillo-Sorghetum occurs in Italy, Kosovo and Slovenia, but its distribution is possibly wider due to conspicuous presence of cosmopolitan species characterizing the association. Our work provides a baseline for the knowledge of an alien-dominated plant community that can invade habitats with high conservation value

Cupressus forests (Acero-Cupression; Habitat code 9290): A New EU Habitat in Italy?

In the European Union, the habitat type 9290 “Cupressus forests (Acero-Cupression)” is reported in more than 20 Natura 2000 sites of Greece and Cyprus. Scientific literature on the habitat 9290 is quite limited and the knowledge on its distribution needs more in-depth analyses and detailed studies. The Nature Reserve “Bosco di S. Agnese” (Siena, central Italy) hosts a large Cupressus sempervirens old-established forest (271 ha) originating from an ancient plantation (dated back to the Etruscan-ancient Roman times). Cupressus sempervirens seems to have found a precise ecological niche thus forming communities where the species is dominant. The aim of this study is to assess whether Cupressus sempervirens forest of Sant’Agnese can be considered as the first example of habitat 9290 in Italy. We compared it with the Cupressus sempervirens forests of the eastern Mediterranean area attributed to the habitat 9290. In June 2022, we collected original vegetation data in our study area. Moreover, additional data from the literature were retrieved for the eastern Mediterranean. A dataset of 217 vegetation relevés from Italy, Greece, Turkey, and Cyprus was obtained. Multivariate analyses (modified TWINSPAN and NMDS ordination) highlighted how the Cupressus sempervirens forest in S. Agnese has remarkable floristic affinities with the ones from Crete and other Aegean islands. Italian and Greek Cupressus sempervirens forests were distinguished in species composition from those in Turkey and Cyprus due to the presence of several species with a western Mediterranean distribution, such as Arbutus unedo, Pistacia lentiscus, and Quercus ilex, and to the absence (in Italy) or poorness (in Crete) of many eastern species, e.g., Acer sempervirens. These preliminary results, as well as the naturalness of the understorey and the potential distribution of habitat 9290 that includes the western Mediterranean basin, support the hypothesis that the EU habitat 9290 is also present in Sant’Agnese Nature Reserve and in Italy. Our study also showed that more extensive and in-depth studies on the typical species and on the distribution of the habitat 9290 in Europe are needed

Low Concentrations of Biochar Improve Germination and Seedling Development in the Threatened Arable Weed Centaurea cyanus

In the context of sustainable agriculture, the search for soil improvers that boost crop growth without harming biodiversity is gaining much attention. Biochar, the solid residue resulting from the pyrolysis of organic material, has recently emerged as a promising bioproduct in enhancing crop yield, but there is a lack of information regarding its effects on arable biodiversity. Thus, in this study, we tested the effect of biochar application on the germination and seedling growth of cornflower (Centaurea cyanus L., Asteraceae), a threatened arable weed, under laboratory conditions. We investigated various parameters, including germination percentage (GP%), mean germination time (MGT), germination rate index (GRI), germination energy (GE%), fresh and dry weight (mg) of seedlings, and radicle length (mm) under biochar treatments at different concentrations: 0% (control), 0.1%, 0.2%, 0.5%, 1%, and 2%. Our findings revealed a significant increase in GP, GE, and GRI at biochar concentrations of 0.5% and 1%. MGT slightly increased at 0.1% biochar. Seedling fresh weight was unaffected by biochar application, whereas seedling dry weight exhibited a significant increase at 0.5% biochar. Radicle length showed a substantial increase under 0.1% biochar on day one and was significantly higher at 0.2% and 1% biochar on day two. However, by day three, no more statistically significant differences in radicle length were observed between biochar-treated diaspores and controls (i.e., biochar had positive effects only in the first stages). These results suggest that the application of biochar at intermediate concentrations (0.5% and 1%) overall provide the most benefit to germination and seedling growth of C. cyanus