Knowledge on alien species is needed nowadays to protect natural habitats and prevent ecological damage. The presence of new alien plant species in Italy is increasing every day. Calabria, its southernmost region, is not yet well known with regard to this aspect. Thanks to fieldwork, sampling, and observing many exotic plants in Calabria, here, we report new data on 34 alien taxa. In particular, we found three new taxa for Europe (Cascabela thevetia, Ipomoea setosa subsp. pavonii, and Tecoma stans), three new for Italy (Brugmansia aurea, Narcissus ‘Cotinga’, and Narcissus ‘Erlicheer’), one new one for the Italian Peninsula (Luffa aegyptiaca), and 21 new taxa for Calabria (Allium cepa, Asparagus setaceus, Bassia scoparia, Beta vulgaris subsp. vulgaris, Bidens formosa, Casuarina equisetifolia, Cedrus atlantica, Chlorophytum comosum, Cucurbita maxima subsp. maxima, Dolichandra unguis-cati, Fagopyrum esculentum, Freesia alba, Juglans regia, Kalanchoë delagoënsis, Passiflora caerulea, Portulaca grandiflora, Prunus armeniaca, Prunus dulcis, Solanum tuberosum, Tradescantia sillamontana, and Washingtonia filifera). Furthermore, we provide the first geolocalized record of Araujia sericifera, the confirmation of Oxalis stricta, and propose a change of status for four taxa (Cenchrus setaceus, Salpichroa origanifolia, Sesbania punicea, and Nothoscordum gracile) for Calabria. The updated knowledge on the presence of new alien species in Calabria, in Italy and in Europe could allow for the prevention of other new entries and to eliminate this potential ecological threat to natural habitats.

We have studied Juniperus oxycedrus L. subsp. badia (H.Gay) Debeaux in the central and southern Iberian Peninsula, where the macrobioclimate ranges from Mediterranean-pluviseasonal-oceanic to Mediterranean-pluviseasonal-continental, and the thermotype from the thermo- to the supramediterranean. The relevés were taken following the Braun-Blanquet phytosociological methodology. A statistical treatment was applied to establish a separation among Juniperus communities. To understand the presence of Juniperus communities in territories dominated by species in the Quercus genus, we applied Thornthwaite’s formula to calculate potential evapotranspiration. The general cluster analysis clearly distinguishes two groups of plant communities and separates the different associations in each group. All the plant communities growing on rocky crests and in extremely steep sloping areas are significantly influenced by the soil. The ombroclimatic index does not explain the presence of plant communities influenced by substrate, so we proposed a new ombroedaphoxeric index which explains the presence of Juniperus communities in territories with a thermotype between the thermo- and supramediterranean. The areas of distribution of Juniperus species are expanding due to the spread of rocky areas; this phenomenon causes an increase in edaphoxerophilous areas and a decrease in climatophilous ones. We propose four new plant associations, with updated structures and floristic compositions. Efficient conservation is possible in both the territories studied (Spain and Portugal) through the implementation of specific cross-border cooperation projects.

The fractal dimension (FD) is calculated for seven species of the genus Quercus L. in Calabria region (southern Italy), five of which have a marcescent-deciduous and two a sclerophyllous character. The fractal analysis applied to the leaves reveals different FD values for the two groups. The difference between the means and medians is very small in the case of the marcescent-deciduous group and very large when these differences are established between both groups: all this highlights the distance between the two groups in terms of similarity. Specifically, Q. crenata, which is hybridogenic in origin and whose parental species are Q. cerris and Q. suber, is more closely related to Q. cerris than to Q. suber, as also expressed in the molecular analysis. We consider that, in combination with other morphological, physiological and genetic parameters, the fractal dimension is a useful tool for studying similarities amongst species.

The plant variability in the southern Iberian Peninsula consists of around 3500 different taxa due to its high bioclimatic, geographic, and geological diversity. The deciduous forests in the southern Iberian Peninsula are located in regions with topographies and specific bioclimatic conditions that allow for the survival of taxa that are typical of cooler and wetter bioclimatic regions and therefore represent the relict evidence of colder and more humid paleoclimatic conditions. The floristic composition of 421 samples of deciduous forests in the south-central part of the Iberian Peninsula were analyzed. The ecological importance index (IVI) was calculated, where the most important tree species were Quercus pyrenaica, Acer opalus subsp. Granatensis, and Corylus avellana. These species are uncommon in the south-central part of the Iberian Peninsula, forming forests of little extension. An analysis of the vertical distribution of the species (stratum) shows that the majority of the species of stratum 3 (hemicriptophics, camephytes, geophites, and nanophanerophytes) are characteristic of deciduous forests, and their presence is positively correlated with high values of bioclimatic variables related to humidity and presence of water in the soil (nemoral environments), while they are negatively correlated with high values of bioclimatic variables related to high temperatures, evapotranspiration, and aridity. This work demonstrates that several characteristic deciduous forest taxa are more vulnerable to disappearance due to the loss of their nemoral conditions caused by gaps in the tree or shrub canopy. These gaps lead to an increase in evapotranspiration, excess insolation, and a consequent loss of water and humidity in the microclimatic conditions.

Several studies have been conducted in the past to clarify various aspects of species in the genus Juniperus L. One critical group is Juniperus oxycedrus L., especially from the taxonomical point of view. For this reason, we have studied the ecology, taxonomy and distribution of the taxa in the J. oxycedrus group. From an ecological and distribution standpoint, in this work we use the ombroedaphoxeric index (Ioex) to explain the presence of Juniperus populations in ombrotypes that are not optimum for these taxa. The controversy over the taxonomy of J. oxycedrus subsp. badia (H. Gay) Debeaux and J. oxycedrus subsp. lagunae (Pau ex C. Vicioso) Rivas Mart. is clarified, and it is accepted as a valid name, J. oxycedrus subsp. badia. The phytochemical differences in essential oils (EO) are addressed and their similarities analyzed; greater similarities are observed between oxycedrus and badia, and between navicularis Gand. and macrocarpa (Sm.) Ball. species. The phytochemical, molecular and distribution differences allow J. oxycedrus subsp. macrocarpa (Sm.) Ball and J. navicularis Gand. to be maintained as species. The results obtained make it possible to establish the rank to which the taxa belong and allow clear discrimination between species in groups that are difficult to interpret. Ecological, bioclimatic, phytochemical and morphometric similarities allow us to subordinate the subsp. macrocarpa to the species J. navicularis.

A study was conducted on 14 grassland communities located in the south of the Iberian Peninsula and their edaphology, which is identified as specific plant associations. The edaphic study of each association allows a rapid evaluation of the nutrient content in the soil without the need for laboratory edaphic analysis. For each phytosociological relevé and soil, samplings were carried out. The field data were subjected to various statistical analysis—canonical correspondence analysis (CCA), Bayesian networks, and decision trees—to establish nutrient content. When the abundance value of the species is 9 in the Van der Maarel scale, there is an increase in the values of several soil parameters. In the case of Hordeum leporinum, when the Van der Maarel index is 9, the Kc (exchangeable potassium in cmol/kg) undergoes the greatest variation, to a value of up to 0.729 cmol/kg. The application of the decision tree to this species reveals that the soil attributes with the greatest influence in the classification are conductivity, %_si (silt texture), pH, and pF 15 atm (pressure at 15 atmospheres (water retention capacity) in %). Indeed, this interlaced edaphic and phytosociological study provides us with a high-value tool to obtain quick information on the content of nutrients in the soil.