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Drought occurs naturally all over the world. Global warming has led an increase in the areas affected by this phenomenon. The study of drought involves the analysis of indicators and indices used to assess changes in the hydrological cycle of a region. A large number of indices developed for drought monitoring are based on meteorological and hydrological variables. This research has applied the Ombroxeric Index for the first time in California. It is based on the concept of ombroxericity: a condition of the territory characterised from an ombrothermic point of view, which can develop in relatively humid areas/zones, depending on the time scale of the study (i.e. monthly, seasonal or annual basis). Temperatures and precipitation from 180 meteorological stations have been considered for a period of observation from 1980 to 2016. In order to know the evolution of this index, a modified trend analysis based on the Mann-Kendall test and a modified Sen slope analysis were used. Empirical Bayesian Kriging was applied as an interpolation technique. Results are presented in both surface and contour maps. California showed a wide range of ombroxeric levels that went from upper strong dry in northern zones, to lower weak arid. Trend results showed an increase in bioclimatic drought throughout the whole State. In addition, summer showed the highest levels on the Ombroxeric Index. An increase in drought trends was observed at the seasonal level, being more pronounced in summer and spring. In both cases are increases in the central (+5 and +3.6 units year−1 respectively) and the southern (+4 and +4.5 units year−1 respectively) areas of the State. Increasing frequency and severity of droughts could have implications for the management of water resources and the survival of Californian vegetation types, such as conifers.

Rising temperatures and changes in precipitation patterns under climate change scenarios are accelerating the depletion of soil moisture and increasing the risk of drought, disrupting the conditions that many plant species need to survive. This study aims to establish the bioclimatic characterisation, both qualitative and quantitative, of ten native Californian Pinales for the period 1980-2019, and to determine their habitat suitability by 2050. To achieve this, an exhaustive search of the Gbif database for records of ten conifer taxa was carried out. To conduct the bioclimatic characterisation of the studied taxa, we worked with the monthly values of average temperature and precipitation for the period 1980-2019 from 177 meteorological stations. Linear regressions was performed in order to compile the future evolution of California's climate. Suitable areas and optimal areas were defined at the present time (1980-2019) and its future projection (2050). We applied Boolean logic and, in this investigation, the Conditional Logic Operator (CON) was used to determine the possible species presence (one) or absence (zero) for each of the 15 variables analysed. In general, most of the conifers studied here will experience a reduction in their habitat range in California by the year 2050 due to climate change, as well as the displacement of species towards optimal areas. Furthermore, the results have highlighted the applicability of bioclimatology to future conditions under climate change. This will aid conservation managers in implementing strategic measures to ameliorate the detrimental impacts of climate change, thereby ensuring the ecological integrity and sustainability of the affected conifer species.

A phytosociological analysis of the Iberian Quercus faginea forests was carried out. For this purpose, 291 relevés were studied. A multivariate analysis consisting of a numerical classification based on the floristic composition of the relevés, was performed. The coherence and explanatory value of the current syntaxa are reviewed. As a result, the diversity of Iberian gall oak forests is resolved into 15 associations characterised according to their floristic, biogeographical, bioclimatic and synecological data supported by the statistical analyses. Thirteen have been described previously, and two new associations are proposed: Glandoro diffusae-Quercetum fagineae and Helianthemo mollis-Quercetum fagineae. A new combination, a lectotypification and a nomenclatural correction are also proposed. The Ios2 (ombrothermic index of the warmest bimonth of the summer quarter), Itc (compensated thermicity index) and Ic (continentality index) indexes proved to be fundamental to explain the syntaxonomic differentiation of the forests in the study. We consider that the differentiation and precision in the definition of clear syntaxonomic entities is vital to prioritize objectives in the conservation of these singular forests, and to ensure their adequate management in the context of the Habitats Directive.

This study identifies and analyzes the plant communities that allow the definition of the geographic limits between Temperate and Mediterranean macrobioclimates, for the center of Portuguese mainland. The altitude of Serra da Estrela, Açor and Lousã, combined with the increase in atmospheric humidity, allows the presence of vegetation typical of a Temperate macrobioclimate. Thus, based on the phytosociological methodology, floristic relevés were carried out in order to identify the series of vegetation existing in these territories. Through these relevés carried out, four new plant associations were identified: Cytisetum grandifloro-striati ass. nova, Scrophulario grandiflorae-Sambucetum nigrae ass. nova, Pruno lusitanicae-Coryletum avellanae ass. nova that lives in the submediterranean bioclimatic variant, mesotemperate humid to hyper-humid. A new association namely Genisto falcatae-Quercetum broteroanae ass. nova with two subassociations were also identified. Based on the vegetation distribution, new biogeographic limits are proposed. Thus, it was intended to identify the southern limits of the European Atlantic Province (Atlantic Orolusitania Subrovince) based on the vegetation cover, namely the distinction between the Estrela Sierran District and a new Biogeographical District, the Alvo-Gardunhense.

This work establishes the relationship between bioclimatology and agronomy. Bioclimatic indices are obtained for several areas under olive cultivation and correlated with olive yields. Due to the effect of climate change on cultivation and the high economic losses it produces, we propose a sustainable development model for the territorial classification of crops based on bioclimatic knowledge. Bioclimatic diagrams are prepared to provide information on water stress in crops so that irrigation can be carried out at the most effective time, a measure that has been shown to lead to water and energy savings for growers. In addition to this development model, we propose the application of non-aggressive cultivation techniques such as the use of living plant cover to ensure the protection of the soil and avoid losses due to climate irregularities. Studies conducted up to the present on applied bioclimatology have yielded promising results in the fields of farming and forestry. The maps and bioclimatic indices of Professor Rivas-Martínez, Ic, Io and It/Itc, are essential for bioclimatic classification. The agricultural development model with a bioclimatic basis ensures economic savings for growers and minimizes the environmental impact of cultivation. In the case of olive cultivation we detected that in 2005 all the cultivated areas that were not in their thermoclimatic optimum were damaged by frost. The widespread cultivation of olive groves in the Mediterranean basin, and mainly in the south of Spain, is reason enough to establish a relationship between its production and its bioclimatic environment. The ombroclimatic study in certain localities under olive cultivation shows that areas with Io <2.5 are unproductive (Jodar, Tabernas), and that their low Io value needs to be supplemented with irrigation water. This means extracting water from aquifers for agricultural use, when the current climate irregularities do not allow the excessive use of subsoil water. For the time

Although there are numerous studies on the floristic composition of the Andean and Caribbean grasslands, there are limited information from a phytosociological point of view. This work therefore aims to highlight the differences in this important vegetation type in these two biodiversity hotspots to gain a better understanding of their floristic and vegetational richness. The floristic composition of Andean grasslands (Ecuador) and the island of Hispaniola is also studied. The reason for this comparative analysis of Andean and Caribbean territories is their tropical character and their bioclimatic similarities. The comparative analysis of Peruvian Andean and Colombian grasslands is based on floristic knowledge from the literature, our inventories on the island of Hispaniola, and the works of Peguero. We applied the phytosociological methodology of Braun-Blanquet and the code of phytosociological nomenclature. We performed a statistical analysis to verify the differences between both community types using the statistical packages PAST© and CAP3. The comparative analysis of Andean and Caribbean grasslands shows a clear floristic and biogeographical differentiation and reveals that the only ecological character they share is their high-mountain attribute. In the Caribbean these communities are found only on the island of Hispaniola (Dominican Republic) in the Central biogeographic sector, Central subprovince, Hispaniola province. These grasslands are exclusive to Hispaniola and have a high rate of endemics. We propose the following new syntaxa: the association Hyperico constanzae-Danthonietum domingensis, the alliance Hieracio domingensis-Deschampsion domingensis, the order Danthonietalia domingensis, and the class Deschampsio-Danthonietea domingensis. We found high biodiversity values for Andean and Caribbean areas. This is due to the intense anthropic activity on the island of Hispaniola, which has led to a high percentage of naturalized plants.

The relict communities of Prunus lusitanica are globally threatened, mainly by climatic and anthropic factors. Solid knowledge about floristic composition and serial dynamics provides a valuable basis for the implementation of management and conservation measures. This article focuses on peculiar communities that occur in hydric-compensated areas of the Iberian Peninsula and south of France, a submediterranean ecotonal area. A hierarchical cluster analysis allowed to identify two new syntaxa. For the first time an association of Prunus lusitanica, Lonicero periclymeni-Prunetum lusitanicae ass. nova, is reported for France, representing the mature stage of a minoriseries of vegetation, attributed to Lonicerion periclymeni. The discovery of populations of P. lusitanica in valleys embedded in the Municipality of Mação (Portugal), represent the new association Smilaco asperae-Prunetum lusitanicae ass. nova, enriched by thermophilous taxa. This relict association occurs in the South Beira District and corresponds to the southern limit of the natural distribution area in mainland Portugal, integrated in the suballiance Fraxino angustifoliae-Ulmenion minoris. Additional notes on the occurrence of P. lusitanica in other areas of the Iberian Peninsula are provided.

The ombroxeric index (OXI), a drought-indicative bioclimatic index based on the Rivas-MartínezWorldwide Bioclimatic Classification System (WBCS), was used in this work to establish theombroxericity trends in a defined study area: the province of Leon (Spain). On the basis oflarge time-scale climatological gridded databases (MOPREDAS and MOTEDAS), with datafrom 1951 to 2010 at monthly, seasonal an annual study level, a Mann-Kendall test-basedtrend analysis was carried out and a geostatistical interpolation procedure, EmpiricalBayesian Kriging (EBK), was applied. Statistically significant increases were revealed in themonths of March and June, as well as in the summer period. These increments are greaterin the southernmost areas and could be related with changes in some teleconnectionpatterns. With this up-to-date approach, besides being aware of the direct bioclimate-altering consequences of the climate change, the prediction of the implications in thevegetation is made possible, due to the typological-predictive character of the model ofclimate-vegetation reciprocity provided by the WBCS.

The microscopic morphology of the leaves of six varieties of Vitis vinifera taken in the León Denomination of Origin is studied: the varieties Albarín Blanco, Malvasía, Mencía, Prieto Picudo, Tempranillo and Verdejo Blanco. The morphology is studied in two leaf fragments (basal and distal) related to the midvein, and parameters such as the thickness of the mesophyll and the stomatal density are measured. There are no works on the microscopic characteristics of the Prieto Picudo variety. All the varieties have the structural characteristics typical of V. vinifera varieties used for commercial purposes. The leaf blades are dorsiventral and hypostomatic with anomocytic stomata. There are two types of trichomes in the abaxial epidermis: some prostrate with a woolly appearance and others upright on which the previous trichomes rest. There are no significant differences between the values for the basal and distal samples of the leaf blade. The Prieto Picudo variety has the thinnest leaf blade and with the lowest stomatal density. It is assumed that the thicker the spongy parennchyma – which implies more intercellular spaces – and the higher the stomatal density, the greater the vulnerability of these varieties to infection by Plasmopara viticola. There are no scientific studies on this subject in the DO León, and very few with the Prieto Picudo variety. One of these studies reports the Prieto Picudo variety as being highly susceptible to the fungus, in which case the starting hypothesis could be rejected and the opposite hypothesis proposed: the thinner the spongy parenchyma and the lower the stomatal density (which are the peculiarities of the Prieto Picudo variety), the greater the vulnerability to P. viticola. However, there are inconsistencies in the works on mildew in the bibliography, possibly because not all the possible variables involved on vulnerability to the fungus are considered.

This work aims to review the natural communities of Pinus halepensis in Spain. The methodology consisted of subjecting 400 phytosociological relevés to georeferencing and statistical, biogeographical, and bioclimatic treatment. We analyse the communities of Pinus halepensis on the Iberian Peninsula and Balearic Islands. Five syntaxa with association rank are described in several works and included in the alliances Rhamno-Quercion and Oleo-Ceratonion. Ephedro-Pinetum halepensis was initially proposed as a community by Torres et al. and subsequently raised to the rank of association by Rivas-Martínez et al. In this work, we have separated the plant communities dominated by Pinus halepensis, which was previously included in other syntaxa, and as a result, we propose four new associations and a new alliance for the Iberian Peninsula: ass. Bupleuro rigidi-Pinetum halepensis; ass. Ephedro nebrodensis-Pinetum halepensis; ass. Rhamno angustifoliae-Pinetum halepènsis; ass. Rhamno laderoi-Pinetum halepensis; all. Rhamno lycioidis-Pinion halepensis. In view of the fact that some of the communities have been published as edaphoxerophilous and climatophilous, we suggest separating the climatophilous from the edaphoxerophilous character in the diagnosis of the communities, and have therefore recently proposed the ombroedaphoxeric index Ioex (Ioex = Pp − e/Tp × CR), which considers positive precipitation Pp, positive temperature Tp, residual evapotranspiration (e), and water retention capacity CR (0.25, 0.50, 0.75). In conclusion, we propose the associations mentioned above, which will allow the implementation of a reforestation treatment in accordance with the natural environment

The aim of this research is to enlarge knowledge of space-time evolution of precipitation in California over the last decade on a monthly, seasonal and annual time-scale. This study also analyses the relationship between precipitation and teleconnection patterns with most influence on Californian climate. The homogeneity of the data from the selected stations was verified and finally 165 meteorological stations were used with an obser- vation period that ranged from 1980 to 2019. In order to evaluate trends and statistical significance, both the non-parametric Mann-Kendall test and modified Sen’s slope method were used. Correlation analysis using the partial non-parametric Spearman Test (95% confidence level) was performed to find out relationships between precipitation and nine teleconnection patterns in the State of California. Spatial analysis was achieved using Empirical Bayesian Kriging (EBK). Finally, this research, as a novelty, shows regionalisation of California State as a function of significance in the correlation of precipitation with teleconnection patterns. To achieve this, Principal Component Analysis (PCA) and Agglomerative Hierarchical Cluster analysis (HCA) was performed. Results show a positive precipitation trend in winter and negative precipitation trend in late summer and autumn. The teleconnection patterns more correlated with precipitation are El Ni ̃no along Southern Oscillation (ENSO), Antarctic Oscillation (AAO) and North Atlantic Oscillation (NAO). Four areas were discerned outlining the Mojave Climate Region (Area 4) by having ENSO as the teleconnection pattern that best account precipitation.

The holm oak woodlands as ecotonic phytocoenoses occur under different ecological conditions, and frequently representing the climax of edaphoxerophilous series of crests and siliceous rocky areas. In this paper we study the floristic, ecological, and biogeographical differences of the edaphoxerophilous holm oak woodlands of the southwestern Iberian Peninsula, included in the Querco rotundifoliae-Oleenion sylvestris suballiance. Our phytosociological (Braun–Blanquet methodology) and numerical analysis (hierarchical cluster analysis) of three formerly described association and our own samples lead us to propose a new association: Ulici argentei-Quercetum rotundifoliae, growing mostly on semihyperoceanic Monchique Sierran Biogeographic District, on rocky slopes and outcrops derived from schists and greywackes. Moreover, we present an overview of ecological features and the diversity of plant communities occurring in the serial dynamic of the thermophile holm oak woodlands of the southwest of the Iberian Peninsula.

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.

In 2018, Spain was the third largest producer and the leading exporter of wine in the world. Viticulture is an important economic activity in the Castilla y León region, and is an element capable of halting the flight from the countryside and favouring demographic settlement in rural areas. A new integrated methodology for characterizing and delimitating areas suitable for vineyard cultivation is proposed here. The approach combines traditional climate indices with others used in bioclimatology and with soil variables, and applies various statistical analyses to select the predictors that best characterize the vineyards. These predictors are then integrated in species distribution models and a geographic information system. The methodology was tested in the Denomination of Origin León (hereafter DO León) in northwest Spain. Ten single models using the maximum entropy modelling algorithm were run for each of the six wine-grape varieties. Single-model projections built as a consensus of the ten models into an ensemble-forecasting approach were later used to generate maps of suitable areas for each variety. The results confirm the delimitation of the DO León as a Denomination of Origin. The bioclimatic variables Compensated Thermicity Index and Continentality Index and the soil variables pH, Clay Content, Soil Retention Capacity and Soil Saturation Humidity are defining for all the varieties studied. Garnacha and Mencía were the most different varieties in relation to their bioclimatic and soil requirements. Suitability maps revealed that the DO could be extended into neighbouring areas up to 30 km around it. The proposed methodology is a useful tool for agronomic and oenological management; it allows a more effective selection of sites for new vineyards, improves vineyard management, and can even be used to protect territories with a historical and cultural heritage of grape cultivation, thus favouring demographic settlement in rural areas and avoiding depopulation.

Global change is expected to impact on the distribution and abundance of forests. Spain represents the south-western limit of distribution for several types of deciduous forests and, as part of the Mediterranean Basin, it has all the characteristics to be affected by climate change. This study analyses the effects of climate change on habitat suitability and vulnerability in four categories of deciduous forests: Fagus sylvatica L., Quercus petraea (Matt.) Leibl., Quercus robur L. and Betula celtiberica Rothm. and Vasc. The approach combines an ensemble platform for species distribution models (SDMs) using three algorithms applied to four global circulation models (GCMs) driven by two representative concentration pathways (RCPs). Bioclimatic, biogeographic, soil and topographic variables were taken into consideration as predictors to build 320 single distribution models. Ensemble-forecasting models were then produced for each forest category and RCPs by computing a consensus of single-model projections. The adapted proposal of the Intergovernmental Panel on Climate Change (IPCC) was also applied to deal with the uncertainty and notify the likelihood of the outcomes. The results revealed generalized losses in habitat suitability compared to current conditions for all the forest categories, which were more drastic for the RCP 8.5 emission pathway. Exceptions worth noting are forests of Fagus sylvatica (likelihood 25%-50%) and Quercus robur (likelihood 75%-100%) in the Orocantabrian biogeo-graphic subprovince, and Quercus petraea formations in the Cantabrian Atlantic subprovince (likelihood 25%- 50%). Betula celtiberica would suffer the largest losses of habitat suitability under the climate change scenarios analysed. The vulnerability analysis confirmed that the deciduous formations least affected by climate change in future will be the Orocantabrian forests, while the Pyrenean and Oroiberian communities are the most vulnerable. The models developed in this study provi

Prunus lusitanica L. is a paleotropical relic species with an Ibero-Maghrebian distribution, which is presently considered as an endangered species, recognized by the Natura 2000 Network (92/43/EEC) as a priority habitat for conservation in Europe. The mountains in the Portuguese mainland central region offer the best location for this species to occur. The main objective of this study is to measure the current conservation status of the communities of P. lusitanica, through the collection of field data, such as the number of existing individuals of each population and their location, which will then be comparatively analyzed based on the previous literature, published at least 15 years ago. Soil characterization analysis was carried out and the main threats to conservation were identified. As a result, a decline of approximately 40% was observed in the number of individuals and in the quality of their habitat. The main threats to their conservation were found to be the seasonal occurrence of rural fires and the expansion of invasive species, such as Acacia dealbata Link and Ailanthus altissima (Mill.) Swingle. Finally, we present the main management methodologies that should be considered

The rocky habitats of southern Portugal are ecosystems with extreme xericity conditions, associated with special abiotic strains. In these unstable ecological conditions, a considerable diversity of plant communities occurs. The objective of this study, carried out in the Algarve and Monchique, and the Mariánica Range biogeographical sectors, is to compare chasmo-chomophytic communities of the southwestern Iberian Peninsula, using a phytosociological approach (Braun–Blanquet methodology) and numerical analysis (hierarchical cluster analysis). From these results, two new communities were identified, Sanguisorbo rupicolae-Dianthetum crassipedis and Antirrhinetum onubensis, as a result of floristic and biogeographical differences from other associations already described within the alliances Rumici indurati-Dianthion lusitani and Calendulo lusitanicae-Antirrhinion linkiani, both included in the Phagnalo saxatilis-Rumicetea indurate class

Se contribuye al conocimiento de la flora palentina haciendo referencia a consideraciones corológicas y taxonómicas de interés, y se citan por primera vez para la provincia: Crepis albida subsp. albida, Diplotaxis erucoides, Iris xiphium, Lycium europaeum, Suaeda vera y Trifolium squamosum.

Fagus sylvatica forests are considered to be of Community interest according to Directive 92/43/EEC. Climate change predictions for Spain point to a warming scenario, coupled with decreasing rainfall, which may have an impact on their future distribution particularly at the extremes of its distribution area. Species distribution models incorporating bioclimatic, topographic and phytogeographic variables were used as predictors to assess their habitat suitability under current conditions and a climate change projection. Ten single models were generated and an ensemble-forecasting model was subsequently built by computing a consensus of single-model projections. The results revealed that ombrothermic indices are the main factors controlling the distribution of Spanish beech forests. They are highly vulnerable to climate change and could suffer a decline in their habitat suitability if climate trends observed are maintained in the future. The least favoured areas for them will be located close to the limit between the Temperate and Mediterranean climates, where they could suffer a loss of habitat suitability. Conversely, suitable new areas could be found mainly in western areas of the Cantabrian Range and in the Central Pyrenees.