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[Question]: Vegetation around the alpine–treeline ecotone faces changes in both climate and land use (i.e. grazing abandonment). Broad-scale shrub encroachment is considered an effect of these changes, but it remains unclear how this process is mediated by local-scale environmental heterogeneity. Our goal is to determine which local-scale environmental factors shape the spatial distribution and temporal trends of alpine dwarf shrub vegetation dominated by Juniperus communis in Mediterranean mountains. [Location]: Three sites in the Central Apennine Mountain Range (Italy): Mt. Terminillo, Mt. Duchessa and Mt. Ernici. [Methods]: Combining a set of environmental variables obtained at a fine scale (25-m resolution) from multi-year remote sensing imagery and field-collected vegetation data, we modelled the occurrence and cover of Juniperus communis-dominated dwarf shrubland, as well as its change over time, as a function of local climate, topography and land use, using linear and generalized mixed effects models. [Results]: Over a period of almost 60 years (1954–2012) shrubland occurrence increased by 12% and shrubland cover by 10% in our study sites. Its current distribution and change over time appear to be strongly shaped by the joint influences of fine-scale topography, above-ground biomass, land use and microclimate. Shrublands have been favoured locally in areas with harsher alpine environmental constraints and stronger resource limitations. [Conclusions]: Our study shows that in the Mediterranean high-mountain environment J. communis dwarf shrubland acts as a stress-tolerant pioneer vegetation, occurring in areas that are otherwise sparsely vegetated. Contrary to our expectations, at fine scales, warmer temperatures and the regional decline in grazing did not favour shrub encroachment. Despite increasing overall, J. communis shrubs have little competitive ability to successfully encroach grasslands, and remain restricted to less-productive areas. Our results confirm that fine-scale environmental heterogeneity can strongly influence shrub distribution and dynamics, thereby modulating future responses in evolving alpine ecosystems., Grant to the Department of Science Roma Tre University, Grant/Award Number: MIURItaly, Dipartimenti di Eccellenza,Articolo 1. Commi 314-337 Legge 232/2016

Climate change is increasingly favouring the occurrence of extreme weather events, affecting species distribution and tree growth. It has been proposed that mixed forests are more resistant to drought spells and heat waves than corresponding monocultures. We sampled tree cores in nine plots along a latitudinal gradient of the Italian Peninsula (Trentino, Molise and Calabria). The objective of the study was to identify radial growth responses in mixed-species and pure plots of European beech and silver fir to climate dynamics and extreme events. Pointer years, as well as correlation and response functions, were used to analyse the climate–growth relationships in mixed-species and pure plots. Climate–growth relationships showed differences between mixed-species and pure plots only at the regional level. In particular, Trentino differed from Molise and Calabria, when considering maximum temperatures. In Trentino, winter (for silver fir) and summer (for both species) temperatures had a less negative impact on the radial growth of trees, in comparison with Molise and Calabria. Nevertheless, correlations between the radial growth and drought indices, and the principal component analysis, showed that plots were relatively unresponsive to summer drought. These results can be important for the implementation of operational techniques that increase the adaptation of silver fir and European beech to climate change, as well as for assisted migration.

Lichens are symbiotic organisms sensitive to climate change and susceptible to a severe decline in diversity, especially in high elevation environments that are already threatened. In this study, we focused on water-energy relationships derived from climatic variables and phylogenetic diversity indices of terricolous lichen communities occurring on a representative Mediterranean mountain. We hypothesized that the variation of precipitation and temperature and their interaction along the altitudinal gradient will shape the phylogenetic diversity and structure of lichen communities. Our results reveal that dry and arid conditions lead to a strong loss in phylogenetic diversity with consequent impoverishment of high elevation lichen communities under a climate change scenario. The interaction between variables, reflecting water-energy relationships with phylogenetic and community diversity patterns, suggests that in a future climate change scenario, the novel climatic conditions may reduce the capability of the species to survive harsher conditions, and Mediterranean mountains may face a severe loss of genetic diversity in a climate change scenario.

The botanical exploration of the Majella National Park has a long tradition dating back to the eighteenth century. However, the lichen biota of this area is still poorly investigated. To provide a baseline for future investigations, in this annotated checklist, we summarised all available information on the occurrence of lichens in the Majella National Park, retrieved from previous literature, herbarium material and original data produced by recent research.The checklist includes 342 infrageneric taxa. However, seven taxa are considered as dubious, thus setting the number of accepted taxa at 335, i.e. 45.8% of those currently known to occur in the Abruzzo Region. This checklist provides a baseline of the lichens known to occur in the Majella National Park, highlighting the potential of this area as a hotspot of lichen biodiversity, especially from a biogeographical point of view as indicated by the occurrence of several arctic-alpine species that form disjunct populations in the summit area of the massif.

Genista longipes Pau forma parte de los matorrales orófilos pulvinulares béticos, una de las comunidades vegetales más vulnerables al calentamiento global. Su distribución más oriental en la península Ibérica se localiza en la culminación de la Serra d’Aitana (Alicante), considerada un área refugio de extrema fragilidad ante cualquier alteración climática. En 2004 se realizó una cartografía corológica de detalle de la distribución de la especie en el sector oriental de la sierra, preferentemente a partir de 1475 msnm, registrándose una pequeña subpoblación aislada a 1300 msnm. Para tratar de entender esta localización disyunta se ha calculado el Índice de Termicidad para cuadrículas de 200 m de lado con el fin de determinar la extensión y subdivisión del piso supramediterráneo, modelizándose un escenario de aumento de las temperaturas que ocasionaría su extinción. Para verificar esta hipótesis, desde 2014 se realiza un seguimiento mediante un exhaustivo trabajo de campo con GPS de precisión. Los resultados arrojan datos controvertidos, puesto que la población aumentó significativamente entre 2004 y 2014 y se encuentra en un declive sostenido desde 2014 a 2018. Se discute el valor de la temperatura como única variable a tratar y la necesidad de analizar el papel del viento y del manejo histórico de la vegetación para entender su dinámica. Genista longipes Pau is part of orophile pulvinular baetic scrubs, one of the one of the plant communities most vulnerable to global warming. Its easternmost distribution in the Iberian Peninsula is located at the culmination of the Serra d’Aitana (Alicante), considered a refuge of extreme fragility in the face of any climatic alteration. In 2004, a detailed corological cartography was made with the distribution of the species in the eastern sector of the sierra, preferably from 1475 mamsl, registering a small isolated subpopulation at 1300 mamsl. To try to understand this disjunct location, the Thermicity Index has been calculated for squares of 200 m on each side in order to determine the extension and subdivision of the supra-Mediterranean level, modeling a scenario of increased temperatures that would cause its extinction. To verify this hypothesis, since 2014 a follow-up is carried out through an exhaustive fieldwork with centimeter accuracy GPS. The results show controversial data, since the population increased significantly between 2004 and 2014 and is in a sustained decline from 2014 to 2018. The value of temperature is discussed as the only variable to be treated and the need to analyze the role of wind and the historical management of vegetation to understand its dynamics. Esta aportación se inscribe en el Proyecto de Investigación I+D SIOSE-INNOVA (CSO2016-79420-R - AEI/FEDER, UE). Ministerio de Economía, Industria y Competitividad, Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad, en el marco del Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016.

Genista longipes Pau forma parte de los matorrales orófilos pulvinulares béticos, una de las comunidades vegetales más vulnerables al calentamiento global. Su distribución más oriental en la península Ibérica se localiza en la culminación de la Serra d’Aitana (Alicante), considerada un área refugio de extrema fragilidad ante cualquier alteración climática. En 2004 se realizó una cartografía corológica de detalle de la distribución de la especie en el sector oriental de la sierra, preferentemente a partir de 1475 msnm, registrándose una pequeña subpoblación aislada a 1300 msnm. Para tratar de entender esta localización disyunta se ha calculado el Índice de Termicidad para cuadrículas de 200 m de lado con el fin de determinar la extensión y subdivisión del piso supramediterráneo, modelizándose un escenario de aumento de las temperaturas que ocasionaría su extinción. Para verificar esta hipótesis, desde 2014 se realiza un seguimiento mediante un exhaustivo trabajo de campo con GPS de precisión. Los resultados arrojan datos controvertidos, puesto que la población aumentó significativamente entre 2004 y 2014 y se encuentra en un declive sostenido desde 2014 a 2018. Se discute el valor de la temperatura como única variable a tratar y la necesidad de analizar el papel del viento y del manejo histórico de la vegetación para entender su dinámica. Genista longipes Pau is part of orophile pulvinular baetic scrubs, one of the one of the plant communities most vulnerable to global warming. Its easternmost distribution in the Iberian Peninsula is located at the culmination of the Serra d’Aitana (Alicante), considered a refuge of extreme fragility in the face of any climatic alteration. In 2004, a detailed corological cartography was made with the distribution of the species in the eastern sector of the sierra, preferably from 1475 mamsl, registering a small isolated subpopulation at 1300 mamsl. To try to understand this disjunct location, the Thermicity Index has been calculated for squares of 200 m on each side in order to determine the extension and subdivision of the supra-Mediterranean level, modeling a scenario of increased temperatures that would cause its extinction. To verify this hypothesis, since 2014 a follow-up is carried out through an exhaustive fieldwork with centimeter accuracy GPS. The results show controversial data, since the population increased significantly between 2004 and 2014 and is in a sustained decline from 2014 to 2018. The value of temperature is discussed as the only variable to be treated and the need to analyze the role of wind and the historical management of vegetation to understand its dynamics. Esta aportación se inscribe en el Proyecto de Investigación I+D SIOSE-INNOVA (CSO2016-79420-R - AEI/FEDER, UE). Ministerio de Economía, Industria y Competitividad, Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad, en el marco del Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016.

Questions:Could mountainpine (Pinus mugo Turra subsp. mugo) located abovethe timberline and at the southern limit of its potential geographic distributionbea promising speciestomonitorclimatic changeinspecificenvironmentssuchas the Mediterranean mountains? Does mountain pine krummholz upwardexpansion result from current climate change? Has the relationship betweenclimate and tree ring growth of mountain pine changed? To what extent doesclimatic variability affect tree ring growth? Could mountain pine upwardexpansion contribute to loss of biodiversity in the undisturbed tree line ecotoneon the Majella massif?Location:MajellaNationalPark,Apennines,Italy.Methods: Dendroclimatological analysis was performed to examine the rela-tionshipbetweentreeringsofmountainpineandclimaticparametersatthetreeline. Climate–growth relationships were analysed using correlation function(CF)analysisandmovingCF(MCF).Results: In the Majella massif, climate variables affected mountain pine treegrowth at the tree line ecotone. Significant correlations were found with springtemperatures and summer precipitation. Essentially, 3 mo played a key role inmountain pine growth: April and May of the current year and October of theprevious year. MCF showed that mountain pine is a sensitive species, in termsoftreeringgrowth.Conclusions: Growing above the limit of tree vegetation, mountain pineproved to be a promising species for monitoring climate- and land use-driveninfluences over tree ring growth at high elevations. Our results show thatmountain pine is particularly sensitive to climate at the beginning and at theendofthegrowingseason.IntroductionIn the central Apennines (Italy), the low altitudinal rangeand marked influence of mediterranean climate set theboundary between alpine and sub-alpine bioclimatic beltsat 2550 m a.s.l. Within the Mediterranean Basin, theApennine range represents a temperate mountain climatic‘island’withinwhichthecentralApenninesformanarchi-pelago of arctic-alpine ‘islands’ (van Gils et al. 2012). TheApennine chain acted as refugia for trees during theW€urmian Late Glacial (Watson 1996), playing an impor-tant role in preservation of endemic high-altitude vegeta

Global change triggers shifts in forest composition, with warming and aridification being particularly threatening for the populations located at the rear edge of the species distributions. This is the case of Scots pine (Pinus sylvestris) in the Mediterranean Basin where uncertainties in relation to its dynamics under these changing scenarios are still high. We analysed the relative effect of climate on the recruitment patterns of Scots pine and its interactions with local biotic and abiotic variables at different spatial scales. Number of seedlings and saplings was surveyed, and their annual shoot growth measured in 96 plots located across altitudinal gradients in three different regions in the Iberian Peninsula. We found a significant influence of climate on demography and performance of recruits, with a non-linear effect of temperature on the presence of juveniles, and a positive effect of precipitation on their survival. Abundance of juveniles of P. sylvestris that underwent their first summer drought was skewed towards higher altitudes than the altitudinal mean range of the conspecific adults and the optimum elevation for seedlings¿ emergence. At local level, light availability did not influence juveniles¿ density, but it enhanced their growth. Biotic interactions were found between juveniles and the herb cover (competition) and between the number of newly emerged seedlings and shrubs (facilitation). Results also highlighted the indirect effect that climate exerts over the local factors, modulating the interactions with the pre-existing vegetation that were more evident at more stressful sites. This multiscale approach improves our understanding of the dynamics of these marginal populations and some management criteria can be inferred to boost their conservation under the current global warming., Funding was provided by the Spanish Ministry for Innovation and Science with the grant Consolider-Montes (CSD2008_00040), and the European Union with the projects BACCARA (CE: FP7-226299, 7FP) and FunDivEUROPE (CE: FP7-ENV-2010. 265171).