Intraspecific variability of leaf form and function across habitat types.

Trait-based ecology has already revealed main independent axes of trait variation defining trait spaces that summarize plant adaptive strategies, but often ignoring intraspecific trait variability (ITV). By using empirical ITV-level data for two independent dimensions of leaf form and function and 167 species across five habitat types (coastal dunes, forests, grasslands, heathlands, wetlands) in the Italian peninsula, we found that ITV: (i) rotated the axes of trait variation that define the trait space; (ii) increased the variance explained by these axes and (iii) affected the functional structure of the target trait space. However, the magnitude of these effects was rather small and depended on the trait and habitat type. Our results reinforce the idea that ITV is context-dependent, calling for careful extrapolations of ITV patterns across traits and spatial scales. Importantly, our study provides a framework that can be used to start integrating ITV into trait space analyses.

Phytochemical diversity within and among Sardinian populations of the endemic Teucrium marum L. (Lamiaceae) is determined by ecological factors.

Wild aromatic plants present high intra- and inter-population chemical polymorphisms which are of great ecological and economic interest; however, the factors influencing the phytochemical diversity of aromatic plants remain still unexplored for many species. Here, Teucrium marum L. (Lamiaceae) has been studied, a plant endemic to the western Mediterranean islands, very well-known from the phytochemical point of view but scarcely investigated regarding the ecological factors that influence its phytochemical diversity within and among populations. The specific aims were to: 1) define the chemical composition variability of its essential oils; 2) determine its inter- and intra-population chemical variability; and 3) evaluate whether the elevation, climatic factors and/or the soil substrate determined the phytochemical variability of T. marum along a gradient from coastal to mountain wild populations on the island of Sardinia (Italy). Fresh T. marum aerial parts were randomly collected from ten individuals in six different localities in Sardinia: three coastal and three mountainous. Dried leaf samples were hydrodistillated using a classical Clevenger apparatus to obtain the corresponding essential oils. The composition of each essential oil was chemically characterised and analyzed by gas chromatography coupled to mass spectrometry. Ninety compounds were identified: among the others, the two compounds that mainly characterised the essential oils of the studied populations, dolichodial and (E)-ß-caryophyllene, are of great economic interest. Statistical analyses showed significant differences in phytochemical essential oil composition among and within the studied populations, which clustered following a geographical pattern rather than a simple climatic or edaphic grouping. Taken together the results here shown shed light on the environmental and geographical conditions that determine the chemical variability of essential oils in T. marum, highlighting a clear coastal vs mountain clustering, which has an ecological and economic relevance, especially for the potential utilization of dolichodial as an environmental-friendly insecticide.

Shrub Cover and Soil Moisture Affect Taxus baccata L. Regeneration at Its Southern Range.

The effect of key ecological and anthropic factors on the recruitment of the common yew (Taxus baccata L.) in Sardinia (Italy) has been analyzed. After bibliographic and cartographic research, followed by field surveys, we found 232 sites where yew grows in Sardinia (as opposed to 69 previously reported in the literature). Among them, we selected 40 sites, located in 14 different mountain chains, characterized by a number of individuals ranging from 11 to 836 adult yews with an average diameter at breast height (DBH) from 13 to 130 cm. By means of generalized linear modeling, we investigated and weighted the effect of ecological, structural, and anthropic factors on the amount of T. baccata recruitment. Our analyses showed that stand recruitment was positively correlated to shrub cover and soil moisture. In particular, shrub cover had a stronger effect, clearly showing that a thicker shrub layer, both bushy and/or spiny, corresponded to a higher number of yew seedlings and saplings. Secondarily, moister sites had a higher number of seedlings and saplings, showing that habitat suitability improved with higher humidity. On the contrary, recruitment was negatively correlated to browsing (both from livestock and wild animals). Our data confirm that the presence of a protective layer of shrubs is a crucial factor for seedling and sapling survival, mostly in relation to protection from summer drought and the browsing of large herbivores. Finally, guidelines for the conservation and restoration of T. baccata communities, referred to as the EU priority habitat 9580* (Mediterranean Taxus baccata woods), have been outlined.

Ethnopharmacobotany and Diversity of Mediterranean Endemic Plants in Marmilla Subregion, Sardinia, Italy.

Human populations in various regions across the world exploit the medicinal properties of plants to treat a wide variety of diseases. Areas with both high rates of endemic taxa and persisting traditional uses of the local botanical resources are key sites for the investigation of Traditional Botanical Knowledge (TBK). Commonly, in these areas, information regarding the medicinal properties of native plants has been transmitted orally from generation to generation, however, a rapid decline in this knowledge has been observed, which can be attributed to socio-economic changes in recent years. The Mediterranean basin is one such site, where human history is intimately entwined with nature. The unique geographical situation and unrivaled environmental heterogeneity of the area, have allowed both the development of diverse civilizations as well as providing the basis for the evolution of extraordinary biodiversity. The Mediterranean basin can therefore be considered a global hotspot of endemic vascular plants, and of traditional knowledge of medicinal and aromatic species. This study researches the historical subregion of Marmilla (central-southern Sardinia, Italy), which was chosen because of its specific cultural and demographic characteristics: i.e., prolonged isolation and extreme longevity of the inhabitants of the area. Semi-structured interviews were conducted with 145 people from the region, and 137 medicinal plants belonging to 62 families were identified, of which around 57,3% were taxa exclusive to the Mediterranean Basin. Findings showed that the most used parts of the plant were the leaves (49%), while as far as preparations are concerned, decoction (50%) was the most used to prepare medicinal formulations, making this the highest number of medico-botanical taxa reported in a study carried out in Sardinia using a similar methodology. In addition, this study contributes towards preventing the loss of TBK by documenting the medicinal traditions, passed down orally for centuries, in the words of the participants, shedding new light on the traditional knowledge of the inhabitants of the island. The findings lay the foundations for future applied studies in the fields of phytotherapy and phytochemical investigation.

Ecology and Evolution of Plants in the Mediterranean Basin: Perspectives and Challenges.

Preserving biodiversity at the global and local scales is a challenge for the future decades, both for protecting species and habitats and to enhance the ecosystem services they provide to the human population [...].

The Endemic Vascular Flora of Sardinia: A Dynamic Checklist with an Overview of Biogeography and Conservation Status.

The vascular flora of Sardinia has been investigated for more than 250 years, with particular attention to the endemic component due to their phylogeographic and conservation interest. However, continuous changes in the floristic composition through natural processes, anthropogenic drivers or modified taxonomical attributions require constant updating. We checked all available literature, web sources, field, and unpublished data from the authors and acknowledged external experts to compile an updated checklist of vascular plants endemic to Sardinia. Life and chorological forms as well as the conservation status of the updated taxa list were reported. Sardinia hosts 341 taxa (15% of the total native flora) endemic to the Tyrrhenian Islands and other limited continental territories; 195 of these (8% of the total native flora) are exclusive to Sardinia. Asteraceae (50 taxa) and Plumbaginaceae (42 taxa) are the most representative families, while the most frequent life forms are hemicryptophytes (118 taxa) and chamaephytes (106 taxa). The global conservation status, available for 201 taxa, indicates that most endemics are under the 'Critically Endangered' (25 taxa), 'Endangered' (31 taxa), or 'Least Concern' (90 taxa) IUCN categories. This research provides an updated basis for future biosystematics, taxonomic, biogeographical, and ecological studies and in supporting more integrated and efficient policy tools.

Gradients of salinity and plant community richness and diversity in two different Mediterranean coastal ecosystems in NW Sardinia.

This study aimed to test if differences in soil salinity, plant richness and diversity were significantly affected by habitat, site and distance from the seashore at three sandy and three rocky coastal sites in north-western Sardinia. Each site has been divided into three belts placed at an equal distance of 50 m from the shoreline. We measured soil salinity using a probe and vascular plants richness and diversity using linear transects at all sites. Average soil salinity varied from 0.115 g/l to 0.180 g/l; it was higher in the rocky habitats than in the sandy ones. A total of 21 species were found per transect/site at the rocky sites and 30 species per transect/site at the sandy sites, with an average of Shannon and Weaver's Diversity Index of 1.8 per each belt at each site. These data confirm that, also in the Mediterranean islands, there are coastal gradients of soil salinity from the seashore to inland areas and that also vascular plant richness and diversity are influenced by the distance from the sea. Soil salinity was strongly affected by the type of habitat, being average at the rocky coasts and negligible at the sandy shores. The site effect was not significant for both soil salinity and plant richness and diversity.

Niche Differentiation at Multiple Spatial Scales on Large and Small Mediterranean Islands for the Endemic Silene velutina Pourr. ex Loisel. (Caryophyllaceae).

The aim of this work is to investigate niche variations in endemic Silene velutina (Caryophyllaceae, Angiosperms) on Mediterranean islands that differ in size. Six populations on both large and small islands were sampled across the geographic range of the species. For each population, 10 plots (1 × 2 m, with a 25 cm grill) were randomly placed to quantify environmental (abiotic and biotic factors and disturbance) and population (demographic structure and reproductive success) parameters. Niche parameters related to substrate, plant cover, community diversity and composition and disturbance showed significant variation in relation to island size. At the regional scale, we detected a broader niche on large islands associated with spatial heterogeneity and island size. In contrast, at the local scale, populations on small islands showed a broader niche, potentially due to a release from competition (low diversity and plant cover and absence of phanerophytes). Populations on large islands had a demographic structure biased towards vegetative individuals (seedlings and juveniles) with few reproductive individuals, while those on small islands had a majority of adults. Together, the results on niche breadth and demographic structure concord with the idea of a strategy based on adult persistence on small islands.

An unknown hotspot of plant diversity in the heart of the Central Apennine: flora and vegetation outline of Mt. Pozzoni-St. Rufo valley (Cittareale, Rieti).

Surprisingly enough, Italy still has some botanically unexplored areas; among these there are some territories between Lazio, Umbria and Abruzzo not included in any protected area. The study area, ranging for 340 ha, includes the mountainous area of Mt. Pozzoni-Mt. Prato-St. Rufo valley, which forms the upper part of the river Velino basin, located in the territory of the municipality of Cittareale (Rieti, Lazio), at an elevation from 1150 to 1903 m a.s.l. The substrate is mainly made of marly limestone of the Meso-Cenozoic Umbria-Marche sedimentary succession. The climate is Temperate and comprises vegetation belts from the montane to sub-alpine. Land cover is dominated by pastures and deciduous forests, with only a few hay meadows. 794 entities have been detected: 16% are considered rare or very rare for the regional territory with several floristic novelties for the regional flora, 6% of the total was found to be endemic to Italy and only eight taxa were aliens. Four taxa are new for the regional flora of Lazio: Arum cylindraceum, Alopecurus pratensis subsp. pratensis, Hieracium bupleuroides and Trinia glauca subsp. glauca. Forest vegetation is represented by beech forests, while dry grasslands are the most widespread vegetation type. The greatest phytocoenotic diversity was found within the secondary pastures. Particularly interesting is the plant community with Iris marsica, which suggests that limestone mountain ledges can represent a primary habitat for this endemic species of the Central Apennine. The presence of several habitats listed in the EU Habitat Directive indicates how the lack of detailed territorial knowledge can lead to the non-designation of conservation sites in areas of high naturalistic value. These findings showed that botanical explorations in territories which are still not known could contribute significantly to the identification of areas of high interest in conserving plant diversity.

Morpho-Colorimetric Characterization of the Sardinian Endemic Taxa of the Genus Anchusa L. by Seed Image Analysis.

In this work, the seed morpho-colorimetric differentiation of the Sardinian endemic species of Anchusa (Boraginaceae) was evaluated. In Sardinia, the Anchusa genus includes the following seven taxa: A. capellii, A. crispa ssp. crispa, A. crispa ssp. maritima, A. formosa, A. littorea, A. montelinasana, and A. sardoa. Seed images were acquired using a flatbed scanner and analyzed using the free software package ImageJ. A total of 74 seed morpho-colorimetric features of 2692 seed lots of seven taxa of Anchusa belonging to 17 populations were extrapolated and used to build a database of seed size, shape, and color features. The data were statistically elaborated by the stepwise linear discriminant analysis (LDA) to compare and discriminate each accession and taxon. In addition, the seed morpho-colorimetric differences among coastal and mountainous taxa were evaluated. Considering the ecological conditions, the LDA was able to discriminate among the Anchusa taxa with a correct identification of 87.4% and 90.8% of specimens for mountainous and coastal plants, respectively. Moreover, the LDA of the 17 populations of Anchusa showed a low separation among species and populations within the coastal group, highlighting how the long-distance dispersal by flotation on the sea water surface and the pollination network may influence the similarity patterns observed. In addition, a misattribution was observed for A. crispa ssp. crispa, which was misclassified as A. crispa ssp. maritima in 14.1% of cases, while A. crispa ssp. maritima was misidentified as A. crispa ssp. crispa in 21.1% of cases, highlighting a close phenotypic relationship between these two taxa. The statistical results obtained through the seed image analysis showed that the morpho-colorimetric features of the seeds provide important information about the adaptation and evolution of Anchusa taxa in Sardinia.

Islands as a crossroad of evolutionary lineages: A case study of Centaurea sect. Centaurea (Compositae) from Sardinia (Mediterranean Basin).

The Mediterranean Basin is a biodiversity hotspot, where islands play a key role because of their high biological diversity, degree of endemicity and human pressure. One of these islands, Sardinia, is a good evolutionary laboratory, especially for the study of complex genera, such as Centaurea. In particular, endemic species of Centaurea sect. Centaurea from Sardinia provides an interesting case study of plant evolution on continental islands. We attempted to clarify the processes leading to the diversification of Centaurea species on Sardinia using bi-parentally inherited nuclear markers and maternally inherited plastid markers. Our plastid results revealed the presence of five lineages of sect. Centaurea on the island. Three of them were defined as three species: C. ferulacea, C. filiformis and C. horrida. The other two lineages highlighted the complex evolutionary history of the two polyploids C. corensis and C. magistrorum. Multiple colonization events from the mainland involving the C. deusta and C. paniculata lineages among others, have led to the diversity of sect. Centaurea on Sardinia. One colonization event likely followed a southern path via the land connection between the mainland, the Calabrian Plate and Sardinia. A second pathway likely followed a northern connection, probably through the Tuscan Archipelago. Implications of these findings on conservation efforts for Centaurea endemics on Sardinia are also discussed.

Pollination features and floral volatiles of Gymnospermium scipetarum (Berberidaceae).

The discovery of few isolated populations of Gymnospermium scipetarum (since now considered as an amphi-Adriatic endemic) in the S-Apennines prompted to investigate, also for conservation purposes, some aspects of its reproductive biology. We aim: (1) to determine if insects play an important role in pollination; (2) to describe the pollinator community; (3) to detect floral scent composition. Experiments of insect exclusion were carried out in the field using 24 flowering individuals: one raceme was capped whereas the nearest one was used as control to ascertain differences in seed set. Pollinator community was detected during the blooming phase of two consecutive flowering seasons by visual observation; insect identification was made at the highest possible taxonomic resolution with the help of digital photographs. In order to determine the chemical composition of the volatiles, we used SPME sampling of cultivated plants. Mann-Whitney U test reveals significant differences for treatment in mean seed set with very low values for capped flowers, thus clearly indicating as insects are crucial for successful pollination. During the 42 h of observations we detected 326 visitors belonging to only three guilds: 79% were Diptera, 20% Hymenoptera and 1% Coleoptera. We identified overall 36 floral organic compounds with only two compounds common to the other studied Berberidaceae. Ambrox was never identified before in the floral scents of any angiosperm. The presence in the scent of several aldehydes and one ketone (benzophenone) could be related to the detected dominance of muscoid flies as pollinators. Floral morphology and composition of the pollinators community indicate a generalist pollination behaviour probably related to its phenology and habitat preference. The possibility of being pollinated also by muscoid flies can be considered an advantage for the reproductive fitness of the species, since these Diptera are abundant in the mountain pastures surrounding the forest habitat of Gymnospermium.

The indigenous vascular flora of the forest domain of Anela (Sardinia, Italy).

The importance of mountains for plant diversity and richness is underestimated, particularly when transition zones between different bioclimates are present along altitudinal gradients. Here we present the first floristic data for a mountain area in the island of Sardinia (Italy), which exhibits Mediterranean bioclimates at the bottom and temperate bioclimate at the top. We discovered a very high floristic richness, despite the fact that the number of endemic taxa is not high and the number of exclusive taxa is very low. Many of the detected taxa are at their range periphery and/or ecological margin. We conclude that climate transition zones in Mediterranean mountains and especially on islands are key areas regarding plant biodiversity and should be better investigated and protected.