Angela Stanisci

Recent Plant Diversity Changes on Europe’s Mountain Summits

Climb Every Mountain Mountaintop floras across Europe appear to be responding to climatic change in terms of upslope species range shifts. Pauli et al. (p. 353) systematically analyzed data gathered from standardized permanent plots on 66 high-mountain environments across Europe. On average, mountaintop species numbers have increased significantly during the last decade. However, this increase is a net effect of gains and losses, with losses particularly affecting mountains of Mediterranean regions and their endemic species. This turnover is largely consistent with model predictions and indicates that high-altitude species, and in particular the rich endemic alpine flora of many Mediterranean mountain ranges, will come under increasing pressure in the predicted warmer and drier climates in this region. European mountaintop flower species richness is increasing on northern summits but decreasing on southern summits. In mountainous regions, climate warming is expected to shift species’ ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe’s major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras’ species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (–1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.

Vascular plant diversity and climate change in the alpine belt of the central Apennines (Italy)

Abstract.The aim of this study is to analyse the vascular flora and the local climate along the altitude gradient in the largest alpine belt of the central Apennines (Majella National Park), and to contribute to the evaluation of the possible effects of global climate changes on the biodiversity of the alpine ecosystem. For this purpose floristic-quantitative analyses and temperature records on three different summits have been carried out by using the methodological protocol of the UE-GLORIA project (2001 2003); the project aims toward a standardised monitoring of flora and temperature in the alpine environment of the main European chains. From the analysis of the changes in species richness along the altitude gradient (2405 m versus 2730 m a.s.l.), it emerged that 70% of species do not reach the highest summit and only 11% of the overall flora is shared by all of the summits examined; a drop in mean temperature has been observed at soil level, along the same gradient from 3.11 to 0.03 °C. Floristic-quantitative and climatic analyses have been carried out even along the horizontal gradient (principal exposures), highlighting a great species richness and vegetation cover in eastward aspects. We singled out some endangered rare species and we proved that the slopes facing east will be the first to be affected by the coming of subalpine species from below, whereas northward exposures will be the most conservative, showing greater inertia toward the invasive process caused by the climate warming.

Spatial connectivity and boundary patterns in coastal dune vegetation in the Circeo National Park, Central Italy.

. Distribution patterns of coastal sand dune plant communities in the Circeo National Park (Central Italy) are quantified and compared by measuring spatial connectivity and richness of community boundaries along the dune profile. The purpose of this study is: (1) to evaluate patchiness and frequency of spatial links between communities; (2) to identify the communities most sensitive to disturbance; and (3) to predict probable changes due to modification of spatial zonation. Data were obtained using belt transects across the Holocene coastal dune zone. Vegetation zonation from the seashore to the foredune slacks is analysed in relation to chorological, phytosociological and life-form types. We found that under relatively undisturbed environmental conditions communities formed a sequence (communities 1 to 7), with the exception of a replacement community, which occupied gaps in the perennial vegetation. The spatial distribution of some communities was reduced as a consequence of disturbance; others became fragmented in small patches or even disappeared. In coastal environments with strong, complex gradients, the existence of certain communities depends on specific links (neighbourhood effects) and high connectivity values do not indicate better conservation conditions.

Changes in composition, ecology and structure of high-mountain vegetation: a re-visitation study over 42 years

Mediterranean high-mountain ecosystems are increasingly threatened by climate change, causing biodiversity loss, habitat degradation and landscape modifications. In this work, we used phytosociological relevés to conduct a re-visitation study in order to analyze changes in floristic composition over the last 42 years in the central Apennines (Majella National Park). We observed changes in floristic composition, along with a significant increase in thermophilic and nutrient-demanding species. Such changes are likely attributable to the combined effect of higher temperatures and the increase in soil nutrients triggered by global change.

Leaf and root trait variability of alien and native species along Adriatic coastal dunes (Italy)

Abstract This study regards the analysis of leaf and root trait variability of the most invasive alien species and some common native species developing along central‐southern Adriatic sand dunes in Italy. The results highlight that large leaf area, the reproductive period in late summer, a biennial/annual life cycle and thick, long roots are useful traits for the successful colonisation of the most invasive species Oenothera biennis, Erigeron canadensis and Xanthium orientale subsp. italicum along the mobile coastal dunes. These alien plants grow in spatial niches generated by eutrophication and human pressure, such as waste deposits on the beach and inter‐dune gaps, flattened and altered by human trampling. We suggest that exotic species in the study area are currently occupying temporal and spatial niches that are not being exploited by native species and, therefore, they are not competing directly for the same resources.

The impact of Acacia saligna invasion on Italian coastal dune EC habitats

Alien species can represent a threat to several ecosystems because they can alter species relationships and ecosystem function. In Italy, Acacia saligna is a major invader and it forms dense stands in coastal environments. We analyze the impact of A. saligna in Italian Mediterranean dune systems. We randomly sampled coastal dune vegetation and investigated its floristic composition with ordination techniques. We compared species richness in invaded and non-invaded plots with rarefaction curves and analyzed the frequency of focal and ruderal species. A. saligna invaded Mediterranean scrub (habitats 2250* and 2260) and coastal Pinus dune wood (habitat 2270*) and it is particularly prevalent in sunny areas of habitat 2270*. We observed an increase in ruderal species and a decrease in focal species in the invaded plots of habitat 2270*. We suggest that more open and disturbed areas are more prone to A. saligna invasion.

Short-term signals of climate change in Italian summit vegetation: observations at two GLORIA sites

Abstract Short-term changes occurring in high mountain vegetation were analysed using the data from two Italian sites already part of the GLobal Observation Research Initiative in Alpine environments (GLORIA – central Apennines and southwestern Alps). The study focused on a set of floristic (endemics), structural (life forms) and ecological (thermic vegetation indicator) variables. Vegetation data were collected according to the GLORIA multi-summit standardized method during the last decade. The re-visitation revealed a moderate decrease in regional endemic flora and significant variations in structural and ecological parameters. The increase in caespitose hemicryptophytes in both sites, in suffruticose chamaephytes in the central Apennines and in rosette-forming hemicryptophytes in the southwestern Alps emerged, highlighting the rapid responses of the alpine vegetation to climate warming. The increase in perennial life forms is related with the expansion of graminoids and small woody plants. These life forms seem to be most suitable to face climate warming in Italian summits. The increase in the thermic vegetation indicator exceeds the mean European summits increment, and this is due to the expansion of thermophilic species. Short-term analyses with fine spatial and temporal resolutions are still necessary to improve our understanding concerning species behaviour in high-elevation ecosystems.

Assessing the diversity pattern of cryophilous plant species in high elevation habitats

This study aimed to better document the diversity and distribution patterns of vascular cryophilous species across major habitat types in a high-elevation Mediterranean system in central Italy. The research addressed the following questions: (a) whether different habitats support similar levels of biodiversity in terms of total vascular plants richness and cryophilous species richness, and (b) how each habitat contributes to the total cryophilous species diversity. A random stratified sampling approach based on a habitat map was applied to construct rarefaction curves for overall cryophilous species richness and habitat type-specific cryophilous richness. Rarefaction curves were also constructed for all-species and exclusive species. To determine whether the targeted species represented a constant proportion of all species, the ratio between the rarefaction curves of the cryophilous species and all species was also calculated. The results highlight the importance of the different habitat types in overall and cryophilous species conservation because these different habitat types had progressively higher richness values. At the regional scale, steep slopes had the highest species diversity, the greatest exclusive species richness and a steep rarefaction curve. The diversity pattern of cryophilous taxa was not related to the general pattern of total species richness, with these species being more common in three habitat types with extreme environmental conditions: ridges, cliffs, and screes. For the establishment of successful biodiversity conservation programs, it is imperative to include species-poor habitats containing a high proportion of cryophilous species, which are considered to be threatened by climate warming.

Life forms variability of mediterranean sclerophyllous forests

Variations in Raunkiaers life-forms spectra for mature Quercus ilex forest stands in N-Mediterranean basin were examined in order to assess their predictability in local vegetation analysis. Physiognomic variations in Quercus ilex communities appear to be mainly determined by structural variations due to intrinsic characteristics (long-term human disturbance all over their range) and to different dynamical status of the stands, without any geographical pattern.

The urban woods of Rome (Italy)

ABSTRACT A phytosociological study of the urban woods of Rome is described. Six syntaxonomical types were identified: 1) Orno-Quercetum ilicis, an edaphic-xerophytic variant of the natural potential vegetation of the city (deciduous Quercus sp. pl. woods); 2) Aquifolio-Fagetum carpinetosum betuli, in the northern slopes of alluvial valleys; 3) Q. suber and Q. pubescens wood, ranked in Quercetalia pubescenti-petraeae order 4) Quercetum ilicis galloprovinciale suberetosum; 5) coppice of Q. cerris and Q. frainetto, which belongs to the Teucrio siculi-Quercion cerridis alliance; 6) mixed mesophile wood of Q. cerris and Ostrya carpinifolia which can be considered a transition between the Doronico-Fagion and the Teucrio siculi-Quercion cerridis alliances. All of these six woody vegetation types are characterised by the large penetration of Mediterranean species belonging to the Quercetea and Quercetalia ilicis and the middle-European ones of the Querco-Fagetea. This mosaic of species exemplifies the bioclimatic...