Andrea Coppi

Biotic homogenization can decrease landscape-scale forest multifunctionality

Significance Numerous studies have demonstrated the importance of biodiversity in maintaining multiple ecosystem functions and services (multifunctionality) at local spatial scales, but it is unknown whether similar relationships are found at larger spatial scales in real-world landscapes. Here, we show, for the first time to our knowledge, that biodiversity can also be important for multifunctionality at larger spatial scales in European forest landscapes. Both high local (α-) diversity and a high turnover in species composition between locations (high β-diversity) were found to be potentially important drivers of ecosystem multifunctionality. Our study provides evidence that it is important to conserve the landscape-scale biodiversity that is being eroded by biotic homogenization if ecosystem multifunctionality is to be maintained. Many experiments have shown that local biodiversity loss impairs the ability of ecosystems to maintain multiple ecosystem functions at high levels (multifunctionality). In contrast, the role of biodiversity in driving ecosystem multifunctionality at landscape scales remains unresolved. We used a comprehensive pan-European dataset, including 16 ecosystem functions measured in 209 forest plots across six European countries, and performed simulations to investigate how local plot-scale richness of tree species (α-diversity) and their turnover between plots (β-diversity) are related to landscape-scale multifunctionality. After accounting for variation in environmental conditions, we found that relationships between α-diversity and landscape-scale multifunctionality varied from positive to negative depending on the multifunctionality metric used. In contrast, when significant, relationships between β-diversity and landscape-scale multifunctionality were always positive, because a high spatial turnover in species composition was closely related to a high spatial turnover in functions that were supported at high levels. Our findings have major implications for forest management and indicate that biotic homogenization can have previously unrecognized and negative consequences for large-scale ecosystem multifunctionality.

Systematics, phylogenetic relationships and conservation of the taxa of Anchusa (Boraginaceae) endemic to Sardinia (Italy)

Abstract Sardinia is a major centre of diversity of Anchusa, but the systematics, phylogenetic relationships and conservation status of the taxa endemic to the island are still poorly known mainly because of their remarkable rarity. We present a study on these endemics based on the results of field research focusing on the distribution, the number and size of the populations, the characteristics of the habitat and the factors of threat. Combined with observations on aspects of reproductive biology, on wild populations and cultivated plants, we evaluate the conservation status of the taxa and propose Red List IUCN categories of vulnerability. Original descriptions, nomenclatural types and karyological data are added. The following Anchusa taxa are endemic to Sardinia: A. capellii, A. crispa ssp. crispa, A. crispa ssp. maritima, A. formosa, A. littorea, A. sardoa and A. montelinasana sp. nov. The latter is described, based on the discovery of a morphologically distinct entity on a mountain in southwest Sardinia. Anchusa littorea was found at a single site after c. 25 years from the last record and 7 years of unsuccessful field research; this species is at the brink of extinction due to the extremely reduced size of the only remaining population. Our complete collection of taxa allowed an analysis of phylogenetic relationships based on DNA sequences from the ITS1 ribosomal genome. In spite of the low variation, this marker produced Maximum Parsimony and Neighbour‐Joining phylograms suggesting that the group is monophyletic and that the split between the two clades of the mountain and coastal endemics has been a key evolutionary event. We assume the three mountain species to be relict schizoendemics ancestral to the coastal taxa, and the Paleozoic siliceous massifs of central and south Sardinia as the centre of origin of the group.

Genetic structure of Linaria capraria Mill. (Plantaginaceae) and endemic species of the Tuscan Archipelago (central Mediterranean)

This study, based on inter-simple sequence repeats in 14 populations of Linaria capraria, shows that genetic diversity at the species level is 0.21 and represents 58% of total variance, whereas the level of intrapopulational genetic diversity is 0.07 and represents 42% of total variance. Gene flow is absent between populations from the same island. On the basis of analysis of molecular variance, three centers of genetic diversity were found: Elba and Pianosa, Montecristo, and Capraia; these correspond to the group of islands that remained isolated during the Würm marine regression. A mean proportion of species-level diversity resides among populations, so we hypothesize that the species has a mixed reproductive system that lies somewhere between obligate outcrossing and obligate selfing. The most genetically diverse populations live in natural and well-isolated rocky habitats that seem to have no particular intervention requirements for conservation but the entire system of populations of this endemic species should be preserved.

Diversity of secondary woody species in relation to species richness and cover of dominant trees in thermophilous deciduous forests

ABSTRACT One of the prominent compositional features of thermophilous deciduous forests of southern Europe is their richness in secondary woody species (AWS). To date, no studies have focused on the diversity and contribution to the ecosystem functions and socio-economic benefits provided by these species. Here, we first characterized species richness and diversity for three main functional groups of AWS, sporadic trees, shrubs and vines, in 53 representative stands of central Italy. Secondly, we explored variations in AWS diversity and composition along a four-level gradient of species richness of dominant trees under comparable site conditions. The 40 AWS taxa recorded showed a remarkable taxonomic singularity at both the genus and the family rank. Dominant tree species richness had no significant effect on AWS species richness and composition, while Shannon diversity of AWS, especially shrubs, was associated with cover of the dominant trees. Each AWS possessed, on average, ca. five ability traits over a total of 13 considered that contributed to important ecosystem functions or expected socio-economic benefits such as wood and food production, conservation of genetic resources (wild crop relatives) and ornamentals. This highlights the key role of AWS, and in particular of sporadic trees, for enhancing multifunctionality of thermophilous deciduous forests.

Demographic and macro-morphological evidence for common reed dieback in central Italy

Background: Phragmites australis dieback syndrome, recently reported for the Mediterranean basin, features several symptomatic traits among which the clumping habit seems to be one of the most diagnostic. Aims: We evaluated the effect of water depth on the intensity of the clumping habit and evaluated the diagnostic role of other traits. Methods: We investigated patterns of macro-morphological (culm height and diameter, flowering head and dead apical bud rates) and demographic (density) traits of P. australis in function of submersion (PF-permanent vs. NF-temporary) at five Italian wetland sites. We related the occurrence of clumping and its frequency with water depth. Results: There were clear trends, modulated by site-specific effects, for most of the considered traits in function of the duration of submersion. The clumping rate was close to zero in NF-stands, reached high values in PF-stands and was positively correlated with water depth. Conclusions: We have shown that permanent submersion with deep water levels plays a crucial role in the occurrence of reed dieback. As all other considered traits, with the exception of the occurrence of dead apical buds, well correlate with the clumping habit, we propose using clumping as a key indicator for detecting potential reed dieback.

Non-monophyly of Buglossoides (Boraginaceae: Lithospermeae): Phylogenetic and morphological evidence for the expansion of Glandora and reappraisal of Aegonychon

The phylogeny of the small Old World genus Buglossoides and its position in tribe Lithospermeae was investigated using nrDNA and cpDNA sequences and morphology. Maximum parsimony and Bayesian analyses of ITS-5.8S and trnL-trnF IGS datasets consistently show that this group is close to Glandora and Lithospermum but not monophyletic. Of the seven spe- cies usually included, two were retrieved in the genus Glandora, i.e., B. goulandrisiorum from northern Greece and B. gastonii from the western Pyrenees. Based also on morphology and ecology, the placement of these two rare, rupicolous endemics in Glandora is here advocated and new combinations are made. The rest of Buglossoides includes two early-diverging clades, one with annual taxa of section Buglossoides and one with the three perennials of section Margarospermum. Morphological, palynological and ecological data support the separation of these two groups in distinct genera, Buglossoides s.str. and the old but largely neglected Aegonychon. Within Buglossoides, two main clades correspond to the B. arvensis and B. incrassata complexes. These show a largely sympatric distribution from the south Mediterranean to central and northern Europe. Com - bined with their strong phenotypic polymorphism, this causes difficulties in the distinction between taxa of the two clades, especially without characteristic cotyledons or fruiting material. Molecular and morphological evidence clearly support the transfer of the west Mediterranean B. arvensis subsp. permixta to the B. incrassata complex.

AFLP Approach Reveals Variability in Phragmites australis: Implications for its Die-back and Evidence for Genotoxic Effects

Phragmites australis is a subcosmopolitan species typical of wetlands being studied in Europe for its disappearance from natural stands, a phenomenon called reed die-back syndrome (RDBS). Although it is conjectured that low genetic variability contributes to RDBS, this aspect remains neglected to this day. Using a molecular fingerprinting approach and a sequence analysis of the trnT-trnL/rbcL-psaI regions of cpDNA, this study aimed to compare the genetic structure of stable vs. RDBS-affected P. australis stands from five wetlands of central Italy. Beforehand, in order to characterize the health condition of reed populations, the occurrence of the main macromorphological descriptors for RDBS was considered on 40 reed stands. Soil samples were also collected to examine the total content of heavy metals. The current study analyzed cpDNA in 19 samples and AFLP profiles in 381 samples to investigate the genetic structure of Phragmites populations. Based on the multinomial-Dirichlet model, an analysis of candidate loci under selective pressure was also performed. The relationships among AFLP data, RDBS descriptors and chemicals were evaluated with the use of Linear Mixed Models. The analysis of the cpDNA shows the occurrence of the haplotypes M (the most widespread), and K here recorded for the first time in Italy. Three new haplotypes were also described. The DNA fingerprinting analysis has produced a total of 322 loci (98% polymorphic) and shows the medium-to-high amount of genetic diversity. The significant genetic differentiation among wetlands (Fst = 0.337) suggests either low gene flow or small effective population size. Moreover, the low amount of outlier loci (only 5; l.5% of the total), seems to indicate the scarce occurrence of selective pressure upon the reed’s genome. Genetic diversity increased in relationship to the decrease in diameter and of flowering buds of the reed, two of the trends associated with the die-back. The current study rejects the hypothesis that genetic diversity massively contributed to RDBS. Moreover, significant relationships between genetic diversity and the total concentration of some heavy metals (Cr, Cu, and Zn) were highlighted, indicating possible genotoxic effects on P. australis. The current study represents a fact-finding background useful for the conservation of common reed.

Responses of serpentine plants to pine invasion: Vegetation diversity and nickel accumulation in species with contrasting adaptive strategies

Introduction of non-native trees is one of the major threats to ecosystem integrity and biodiversity. Stands of maritime pine (Pinus pinaster Ait.) introduced decades ago represent a threat to the specialized plant communities of serpentine outcrops in Italy. This study investigates the effects of such invasions at the community and species level, based on vegetation sampling in three selected sites with comparable environmental conditions. Pine cover caused a decrease of α-diversity by lowering the species evenness of the community, though species richness was not negatively affected. Compositional changes between the two habitats were significant but not clearly associated with a decrease in taxonomic distinctness in the pine stands. As many as nine indicator species were found in the open vegetation, along with the obligate endemics Odontarrhena bertolonii and Armeria denticulata. Both of them declined in the pine stands. Here, an increase in the phytoavailable nickel fraction was associated with a decrease in total nickel concentration in the soil, via mobilization of the metal caused by lowering of pH induced by the conifer litter. The nickel-hyperaccumulator O. bertolonii was able to maintain high metal concentrations in the shoots despite a decrease in root concentration, resulting in a higher shoot/root ratio in the pine stands (~20). Conversely, shoot/root ratio in the non-accumulator Plantago holosteum was <1 and not affected by the conifer, as well as its abundance in this anthropogenic habitat. Contrasting responses of the two species were likely due to their different sensitivity to modified light and soil conditions, whereas stability of shoot nickel-concentration in O. bertolonii did not support increased predation by natural enemies as one of the causes for its decline under the conifer. Progressive thinning of these stands is advocated to limit soil nickel mobilization and to restore a unique ecosystem with its endemic metallophytes.

Claviceps arundinis identification and its role in the die-back syndrome of Phragmites australis populations in central Italy

Abstract Common reed Phragmites australis (Cav.) Trin. ex Steud. is one of the most widely distributed angiosperms with important ecological functions. In recent decades, it has been affected by a severe decline known as reed die-back syndrome (RDBS), the causal factors of which are still under investigation. Among the biotic factors that influence the dynamic of the reed population, the role of microorganisms is still poorly understood. During surveys carried out on P. australis populations in Central Italy, Claviceps-like sclerotia were detected: is Claviceps infection related to P. australis sexual reproduction and seed production? Could Claviceps infection be involved in the RDBS? These are the questions that we address. We characterized the sclerotia at the morphological, molecular, and chemical level and we demonstrated that they belong to Claviceps arundinis Pažoutová & M. Kolařík. To our knowledge, this is the first report of C. arundinis on P. australis in Italy. Furthermore, the association of C. arundinis with RDBS was evaluated considering a set of macromorphological traits generally related to RDBS, such as P. australis clumping habit, culm height and diameter. No correlation was seen between the occurrence of C. arundinis and the declining status of reed populations.

Oomycete Communities Associated with Reed Die-Back Syndrome

Phragmites australis (Cav.) Trin. ex Steud. die-back is a widely-studied phenomenon that was first discovered in northern Europe and that, until recently, was almost unknown in the Mediterranean basin. It has been described as a complex syndrome affecting reed populations leading to their retreat and decline, with significant impacts on valuable ecosystem services. Among the factors that cause the decline, soil-living microorganisms can be crucial. The aims of this study were to analyze the diversity of oomycetes communities associated with reed stands, and to understand whether they could play a key role in the decline. Variations in the structure of oomycetes communities were studied by metabarcoding of the internal transcribed spacer (ITS) 1 region of ribosomal DNA, from the sediments of five Italian freshwater ecosystems. They were chosen to cover a large variability in terms of surface area, water depth, microclimate, and presence of documented reed retreat. From 96 samples collected from reed roots, rhizosphere, and bulk soil, we assembled 207661 ITS1 reads into 523 OTUs. We demonstrated that oomycete communities were structured by several factors, among which the most important was die-back occurrence. Our study also indicates that Pythiogeton spp. could be potentially involved in the development of die-back. The role of heavy metals in the soil was also explored, and cadmium concentration was shown to affect oomycetes distribution. This study represents a significant step forward for the characterization of microbial communities associated with reed die-back syndrome and helps to gain knowledge of the complexity of these important wet ecosystems.