Mediterranean Influence Research Articles

Relicts of Threatened Biodiversity: Similarities and Differences among the 7230 EU Habitat Plant Communities on Montane Plateaus of Central Apennines, Italy.

The habitats protected by the European Union (EU) include most peat vegetation, such as mires, swamp mires, fens, and peat bogs-all belonging to the classes Oxycocco-Sphagnetea and Scheuchzerio-Caricetea fuscae and carrying the Habitat Codes 71xx and 72xx. These types of vegetation are typical of cold and cool temperate climates, while they become rarer in Southern Europe where Mediterranean influences prevail, representing relic fragments of the past glacial climatic conditions there. Because of their limited extension and the increasing warmth and drought due to climate change, they are seriously threatened. Even if many studies were performed, their richness and distribution across Europe are still not well-understood, and only a few examples are known from the Central and Southern Apennines to date. In order to provide the syntaxonomical classification of the alkaline fens referable to the EU Habitat 7230 found on the mountain plateaus of the Central Apennines, we analyzed their species structure and flora composition, together with their chorological and ecological characteristics. We also evaluated their conservation status, pressures, and threats. The alkaline fens of the Central Apennines are found to be poorer in diagnostic species when compared to similar communities of Central and Northern Europe. However, they are rich in the species of the surrounding meadows and pastures. Among them, the new subassociation Caricetum davallianae caricetosum hostianae is described.

Twenty years of population dynamics in European beech-oak forest at their rear range margin anticipate changes in its structure and composition

There is an increasing interest in restoring degraded forests, which occupy half of the forest areas. Among the forms of restoration, passive restoration, which involves the elimination of degrading factors and the free evolution of natural dynamics by applying minimal or no management, is gaining attention. Natural dynamics is difficult to predict due to the influence of multiple interacting factors such as climatic and edaphic conditions, composition and abundance of species, and the successional character of these species. Here, we study the natural dynamics of a mixed forest located in central Spain, which maintained an open forest structure, due to intensive use, until grazing and cutting were banned in the 1960s. The most frequent woody species in this forest are Fagus sylvatica, Quercus petraea, Quercus pyrenaica, Ilex aquifolium, Sorbus aucuparia, Sorbus aria and Prunus avium, with contrasting shade and drought tolerance. These species are common in temperate European deciduous forest and are found here near their southern distribution limit, except for Q. pyrenaica. In order to analyze forest dynamics and composition, three inventories were carried out in 1994, 2005 and 2015. Our results show that, despite the Mediterranean influence, the natural dynamics of this forest has been mainly determined by different levels of shade tolerance. After the abandonment of grazing and cutting, Q. pyrenaica expanded rapidly due to its lower shade tolerance, whereas after canopy closure and forest densification, shade-tolerant species gained ground, particularly F. sylvatica, despite its lower drought and late-frost tolerance. If the current dynamics continue, F. sylvatica will overtake the rest of the species, which will be relegated to sites with shallow soils and steep slopes. Simultaneously, all the multi-centennial beech trees, which are undergoing a rapid mortality and decline process, will disappear.

Egg parasitoids of Thaumetopoea pityocampa in the region of Gyumyurdzhinski Snezhnik in Eastern Rhodopes, Bulgaria

The region of Gyumyurdzhinski Snezhnik in the Eastern Rhodopes is the closest in Bulgaria to the Aegean Sea. However, the climate is characterized by specific parameters that are determined by its relief. It is poorly protected from the invasion of cold air masses from the north. From the south, the Gyumyurdzhinski Snezhnik hill restrains the Mediterranean influence. The orography of the area favors the retention of cold air masses and a further drop in temperatures. The experimental material for the study includes 5 generations of Thaumetopoea pityocampa (2016, 2017, 2018, 2019, and 2022), collected in 31 locations of four State Forestry Enterprises: Kirkovo, Ardino, Momchilgrad, and Zlatograd. The sample for analysis included 693 egg batches with 148420 eggs in them. Seven primary egg parasitoids were established in this region: Ooencyrtus pityocampae, Baryscapus servadeii, Pediobius bruchicida, Anastatus bifasciatus, Eupelmus vesicularis, E. vladimiri, Trichogramma sp. and one hyperparasitoid (B. transversalis). Dominant parasitoids were B. servadeii and O. pityocampae, and E. vladimiri and P. bruchicida – occasional parasitoids. The hyperparasitoid B. transversalis participated in the complex with a relatively low share. The survival of the egg parasitoids in the laboratory conditions, in which the samples were kept, was low. The total mortality of the parasitoids in larval and adult stages was 47.8%. After collecting the samples, in laboratory conditions, a total of 442 individuals of the hyperparasitoid B. transversalis emerged, of which 56.3% were females and 43.7% were males. The average number of pine processionary moth eggs in a batch was 214.2. 70.8% of all the eggs in the samples hatched successfully. The egg parasitoids are a very serious natural factor, regulating the density of the pine processionary moth, but their impact varied from 2.1% to 30.3%. The natural characteristics of the area, the air temperature during the stages of eggs and young larvae, are favorable for the development of the pine processionary moth. Unhatched larvae without the influence of entomophages were 7.2%.

Mediterranean Influence on the Climatic Regime over the Balkan Peninsula from 1901–2021

The Balkan Peninsula is a geographical region under various large-scale climatic influences, one of the most significant being the Mediterranean Sea in the southwest and the continent in the northeast. The novelty of this study is that the border between the zones with prevailing maritime or continental climate conditions is clearly identified by the month with the highest precipitation during the year. We use the gridded data product TS_4.06 of the Climatic Research Unit for monthly precipitation to identify the timing of the maximum rainfall at different locations. The grid boxes with highest precipitation in the cold part of the year (October to March) are considered to be under prevailing Mediterranean influences and, on the contrary, the ones with the highest precipitation are in the warm part of the year (April to September); these are climates with prevailing continental characteristics. In general, this border separates the zones with Cs and Dw types of climates. Its spatial variability at a decadal time-scale is discussed for the period from 1901–2021 and a general weakening of the Mediterranean influence over the Balkan Peninsula is found. However, for the last three decades, from 1991–2021, the tendency is the opposite. A periodicity of ~20 years is identified, suggesting that during the decade of 2020–2030, the Mediterranean influence in this region will dominate.

Morphometric and genetic evidence for cattle imports from the Mediterranean into present-day Austria during the Iron Age

Osteometric data and morphological observations on cattle bones from Roman period sites from present-day Austria suggest the arrival of a new large-sized cattle population, which has been connected with the conquest of this area by the Romans and subsequent import of a Mediterranean population. Therefore, recent documentation of some large-sized cattle remains, similar to those found in the Roman period, already from two Late Iron Age sites, one even north of the Danube, indicate an earlier presence of this cattle population together with the typical small-sized Iron Age cattle population. We applied ancient mitochondrial DNA analysis on fourteen Iron Age and Roman period cattle teeth and bones to find genetic evidence concerning possible cattle mobility. Our results show the presence of haplogroup T3, a common European haplogroup, for both large-sized (imported) and small-sized (Iron Age) cattle. For the first time in present-day Austria, our documentation of haplogroups T1 (common in cattle populations from southern Europe) and T5 (so far recorded only in Italian and some Croatian cattle populations probably due to Mediterranean influence) in the Iron Age large-sized cattle provides evidence for cattle imports from the Mediterranean already during the Iron Age.

Macroinvertebrate community structure and ecological status in Portuguese streams across climatic and water scarcity gradients

Climatic and hydrological variation is of utmost importance in regions of the globe facing water scarcity and river intermittency (e.g. areas under Mediterranean influence). The main aim of this study was to compare the macroinvertebrate community structure and its bioindicator value (i.e. waterbody ecological status) in streams from three Portuguese regions (Regions C, N and S), representing distinct climatic features and water availability scenarios. Results showed that, overall, sampling sites differed in their climatic, hydromorphological and physical and chemical features, and environmental (abiotic) and ecological (community dissimilarities) gradients among regions were clearly identified. Sites from Regions C (wettest) and S (driest) represented non-overlapping clusters of samples, both in terms of their environmental context and ecological (dis)similarity; sites from Region N occupied an intermediate position, and their macroinvertebrate community was highly variable locally. This coincided with overall higher ecological quality and uniformity in Region C, whereas Regions N and S were more heterogeneous and generally presented lower ecological quality. Our data showed that climate (and associated water scarcity) is coupled with other environmental drivers of the macroinvertebrate community structure, highlighting a shared influence of the three environmental components (climatic, hydromorphological, and physical and chemical) in the modulation of macroinvertebrate communities.

A mediterrán növényalkalmazás jelene és jövőbeli lehetőségei

In Hungary, the Mediterranean influence is more and more strongly featured typically by considerable climatic extremes between winter and summer. The Mediterranean vegetation has adapted to these changes and tolerates dry hot summers and mildly rainy winters. It will gain more and more space in the future both in public and private areas – mainly on the southern slopes of South Transdanubia and the Balaton Highlands, later maybe on the same southern slopes of Buda Mountains and the Velence Mountains, and afterwards in some areas of the Northern Middle Mountains. Thus it is useful to gain knowledge about the Mediterranean coastland’s vegetation and profit from it. Keeping in mind the economic water management, it is advisable to decide on drought and frost-tolerant species while planting them in a harmonic and decorative manner in orchards and lawn areas in the future. This is what the presented recommendations are for.

Mapping the spatial variability of rainfall from a physiographic-based multilinear regression: model development and application to the Southwestern Iberian Peninsula.

A physiographic-based multilinear regression model supported by GIS was developed to estimate spatial rainfall variability in the Southwest Iberian Peninsula. The area study includes a wide diversity of landscape features and comprises four Portuguese regions and one Spanish province (totalizing 28,860 km2). The region suffers a very strong Mediterranean influence, with a major cleavage between winter and summer seasons. Thus, the analysis was carried out separately for the wet (October to March) and dry (April to September) semesters. From an initial set of 10 explanatory physiographic variables, five were selected to be used in the multilinear regression, as they allowed generating models by map algebra that fitted well with the last 40years of monthly rainfall data records. These records were obtained from 163 weather stations, filtered from an initial set of 230 (142 stations in Portugal and 88 in Spain). The correlation between the physiographic-based multilinear regression model and a model obtained by interpolation from rainfall historical data showed to be good or very good in approximately 75% of the area under study. Results show that physiographic-based models can be effectively used to estimate rainfall where there is a lack of rain gauges, or to densify spatial resolution of rainfall between rain gauges.

Ancient DNA refines taxonomic classification of Roman equids north of the Alps, elaborated with osteomorphology and geometric morphometrics

Hybrids of horse and donkey, which have been valued in the Mediterranean basin since the Iron Age, became integrated into the animal world north of the Alps in the course of Romanization. Until now, however, their true contribution to the economic and military life in the northern Roman provinces Raetia, Noricum and Upper Pannonia (southern Germany, eastern Switzerland and Austria) has remained unknown in the absence of robust identification methods based on morphometric approaches. We confronted morphological identification of 405 equid specimens collected in the Late Iron Age (Celtic) (∼2nd – 1st century (c.) BCE) and Roman (∼1st – 5th c. CE) archaeological contexts with their ancient DNA signatures. Our multi-method study demonstrates that although ancient DNA and morphological approaches (including standard osteomorphology and geometric morphometrics) provide overall >85% matching results, in the case of hybrid animals, the extent of overlap with ancient DNA drops to ≤52%. Out of five skeletal elements studied here (mandibular premolars and molars, metapodials, humeri and tibiae), only premolar mandibular teeth (P3, P4) provide good enough accuracy in hybrid classification (89%) based on geometric morphometrics, making it the preferred element and method in future zooarchaeological studies, when ancient DNA data is not available. Moreover, our data show that, although not yet present in the preceding Iron Age, one in six equids in Roman times is a mule, suggesting a strong Mediterranean influence on the use of equids in daily life north of the Alps.

Enhanced spring warming in a Mediterranean mountain by atmospheric circulation

We analyzed trends of air temperature across the Cévennes National Park in Southern France, a mid-altitude coastal mountain experiencing a rapid spread of forests at the expense of rangelands and submitted to Mediterranean Sea influences and so, impacted by local and regional processes of climate change. Since 1980, April to June warming trend reached a maximum temperature increase of + 0.124 °C year−1 and uniform whatever the altitude. Minimum temperature increased by + 0.058 °C year−1 at 500 m altitude and + 0.089 °C year−1 at 1500 m. Concomitantly, forest cover is increasing by + 0.51% year−1. Using an intrinsic biophysical mechanism model, we demonstrated that, at monthly scale, the forest surface is 1.7–3.1 °C cooler than that of nearby grasslands. As a result, the decrease in albedo corresponding to the conversion from grasslands to dense forests, translates into a cooling of maximum air temperatures of 0.023 °C year−1 which contributes to slow down the warming rate enhancement. Spring warming trends co-varied with negative WeMO phases associated with a low in the Gulf of Cádiz and an anticyclone in Central Europe. An east to west pressure gradient increases atmospheric humidity leading to a strong water vapor feedback, enhancing the forcing of thermal long wave radiations and hence the rise in temperature.

Last glacial fluctuations in the southwestern Massif Central, Aubrac (France): First direct chronology from cosmogenic 10Be and 26Al exposure dating

The chronology of the late Pleistocene glaciation in the Massif Central, France, is not well documented and there are divergent hypotheses regarding the timing of glacial events in this area. This study aims at reconstructing the chronology of late Pleistocene glacial fluctuations in the Aubrac Mountains. We present a new set of Be-10 and Al-26 exposure ages from twenty erratic boulders embedded in six glacial landforms. Glacial landforms were sampled to determine the timing of three glacial stades and the deglaciation of the Aubrac Mountains. These new data allowed us to constrain the timing of: (i) the Local Last Glacial Maximum, which is coeval with the early Marine Isotopic Stage 2 (MIS 2) (28–24 ka), and (ii) the Grandvals and Bouquincan stades, which are both coeval with the late MIS 2 (24–16 ka). Deglaciation occurred during Heinrich Stadial 1 (18–15.6 ka). This new direct glacial chronology is supported by regional paleoenvironmental proxies and it updates the chronostratigraphic framework available for the southwestern Massif Central. Western European atmospheric circulation changes (i.e., a southward shift in North Atlantic storm tracks and Mediterranean influences) during MIS 2 were identified as significant factors controlling glacier growth in the Aubrac Mountains as well as other glaciated mountains within the southwestern Massif Central, such as the Cantal, Margeride and Lozère mountains.

Confirmed presence of aedes (rusticoidus) refiki Medschid, 1928 in a continental dry Mediterranean peri-urban environment in south-central Spain

BackgroundThe ‘snow-melt mosquito’ aedes (rusticoidus) refiki is a rare species with a wide distribution in Europe that is usually defined as an aggressive mosquito for mammals, including humans. During a mosquito survey in a peri-urban area in south-central mainland Spain, adult Ae. refiki females were captured and identified by morphological traits. The presence of this species of mosquito has never been molecularly confirmed under continental dry Mediterranean climatic influence with scarce number of days with snow on soil. The aim of this study was to confirm by amplification and sequencing of mitochondrial cytochrome c oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2) region.ResultsWe also successfully amplified and typed the species molecularly by COI and ITS2 regions. The peri-urban area where Ae. refiki was found contrasts with the reported cold, humid and snowy environments required by the species to breed.ConclusionsThis finding suggests that the species is already adapted to continental dry Mediterranean environments, questioning whether it is a truly stenotopic species of cold snowy environments.

Phytochemical and Nutritional Profile Composition in Fruits of Different Sweet Chestnut (Castanea sativa Mill.) Cultivars Grown in Romania

Chestnut (Castanea sativa Mill.), a valuable fruit crop, is cultivated in small areas in Romania, mostly in the west, where the moderate continental climate has a slight Mediterranean influence. This work aims to investigate the bioactive characteristics (total polyphenols, total flavonoids and antioxidant activity), individual polyphenolic composition, phytochemical and nutritional HRMS screening profiles, sugar and mineral composition of six sweet chestnut cultivars, namely ‘Marsol’, ‘Maraval’, ‘Bournette’, ‘Précoce Migoule’ and ‘Marissard’ grown at Fruit Growing Research—Extension Station (SCDP) Vâlcea, in Northern Oltenia, Romania. Fruit samples were collected in two consecutive years, in order to study the impact of genetic variability between cultivars and the influence of the different climatic conditions corresponding to different cultivation years. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) allow the discrimination between the sweet chestnut fruits harvested in different years and different sweet chestnut cultivars. Analytical investigations revealed that sweet chestnut cultivars grown in Romania show similar bioactive, phytochemical and nutritional composition to cultivars grown in the large European chestnut-producing countries, indicating the high adaptation potential of the chestnut in the temperate continental zone with small Mediterranean influences characteristic of the southwestern area of Romania.

Vapour source and spatiotemporal variation of precipitation isotopes in Southwest Spain

AbstractThe δ2H and δ18O composition of 77 precipitation samples collected between January 2014 and April 2019 from two sites across the Guadalquivir Basin, SW Spain, were analysed. The first site is located in an urban area of Seville at 100 km distance to the Atlantic coast and the second site is located in a dune area of the Doñana National Park a few kilometres from the coast. Sampling was performed within intervals of at least 14 days if rain occurred but frequently intervals were longer according to the rainfall incidence. Samples from both sites are available for the period February 2016 to June 2018 with six samples containing identical rain events at both locations. Precipitation weighted averages and local meteoric water lines produced by weighting and non‐weighting regression methods are presented for its use in hydrological applications. Results show a remarkably high variability in δ2H and δ18O values and precipitation weighted average d‐excess values of 11.8‰ and 13‰ at the sites Plaza de España and Doñana, respectively. Temperature and amount effects were found to be weak. A significant influence of secondary evaporation for single rainfall events during summer was identified by enriched isotopic signatures with reduced d‐excess values plotting close or below the global meteoric water line. Backward trajectory analysis of 115 days with daily rainfall above 3 mm yield a predominant Atlantic Ocean vapour source with negligible Mediterranean influence and therefore, d‐excess variability is attributed to the different ocean surface conditions of relative humidity and sea surface temperature. Parallel sampling indicate very similar isotopic signatures at both sites and point to the existence of thermal effects of the Plaza de España site in Seville city during the summer season.

Explaining recent trends in extreme precipitation in the Southwestern Alps by changes in atmospheric influences

This article analyzes recent trends in extreme precipitation in the Southwestern Alps and compares these trends to changes in the occurrence of the atmospheric influences generating extremes. We consider a high-resolution precipitation dataset of 1 × 1 km2 for the period 1958–2017. A robust method of trend estimation in extreme precipitation is considered, based on nonstationary extreme value distribution and a homogeneous neighborhood approach. The results show contrasting trends in extreme precipitation depending on the season. In autumn, most of Southern France shows significant increasing trends, with increase in the 20-year return level between 1958 and 2017 as large as its average value over the period, while the Northern French Alps and the Swiss Valais show decreasing extremes. In winter, significant increasing extremes are found in the valleys and medium mountain areas surrounding the Northern French Alps, while the inner French Alps, the Swiss Valais and the Aosta Valley show significant decreasing trends. In the other seasons, the significant trends are mostly negative in the Mediterranean area. Comparing these trends to changes in the occurrence of the atmospheric influences generating extremes shows that part of the significant changes in extremes can be explained by changes in the dominant influences, in particular in the Mediterranean influenced region that shows the most organized trends. In particular, the strong positive trends in extreme precipitation in autumn in Southern France are concomitant with an increase in Mediterranean influence generating extremes.

Characterisation of Extreme Precipitation Events in the Pyrenees: From the Local to the Synoptic Scale

Mountain systems within the Mediterranean region, e.g., the Pyrenees, are very sensitive to climate change. In the present study, we quantified the magnitude of extreme precipitation events and the number of days with torrential precipitation (daily precipitation ≥ 100 mm) in all the rain gauges available in the Pyrenees for the 1981–2015 period, analyzing the contribution of the synoptic scale in this type of event. The easternmost (under Mediterranean influence) and north-westernmost (under Atlantic influence) areas of the Pyrenees registered the highest number of torrential events. The heaviest events are expected in the eastern part, i.e., 400 mm day−1 for a return period of 200 years. Northerly advections over the Iberian Peninsula, which present a low zonal index, i.e., implying a stronger meridional component, give rise to torrential events over the western Pyrenees; and easterly advections favour extreme precipitation over the eastern Pyrenees. The air mass travels a long way, from the east coast of North America, bringing heavy rainfall to the western Pyrenees. In the case of the torrential events over the eastern Pyrenees, the trajectory of the air mass causing the events in these areas is very short and originates in the Mediterranean Basin. The North Atlantic Oscillation (NAO) index has no influence upon the occurrence of torrential events in the Pyrenees, but these events are closely related to certain Mediterranean teleconnections such as the Western Mediterranean Oscillation (WeMO).

Microscopic Re-Examination of an Unique Bone Artefact: The Figure of a Theatrical Actor Found at The Roman Fort Iža/Leányvár (Slovakia)

Abstract In 1955, a figure, representing a comic actor, was discovered on a spoil heal in the Roman Fort of Iža. It is a unique find without close parallels in the whole of the Roman Empire, making it difficult to determine from which object it was derived or what was its function. The results of new research are presented here and demonstrate the object is a fragment of a luxury, figural knife handle made from bone rather than ivory. It was probably produced in a provincial workshop under a Mediterranean influence where similar figures, though from different materials, occur throughout the second century.

First records of a potentially new plant community from the ruderal vegetation in the Black Sea Coast, Bulgaria

The paper presents the first data of an unreported plant community dominated by Hordeum leporinum Link and Bituminaria bituminosa (L.) Stirt. (class Stellarietea mediae R. Tx., Lohmeyer et Preising in R.Tx. 1950). It is currently established in four localities in the region of the Black Sea coast, between the town of Ravda and the town of Nessebar, Bulgaria. Among the characteristic features of the community are: (i) it occupies places with an active human presence near the beach; (ii) preferences for shallow san-dy or rocky soils; (iii) Bituminaria bituminosa (L.) Stirt. as a dominant, diagnostic and constant species for the community. Other diagnostic species for the association are Anchusa officinalis L., Malva sylves-tris L., Sonchus arvensis L. and Avena fatua L. (iv) annual and perennial species have an equal participa-tion in the community; (v) increased presence of diagnostic species for the class Artemisietea vulgaris Lohmeyer et al. ex von Rochow 1951. Phytogeographically, the species composition of the community has a strong Mediterranean influence. In close proximity to its reléves there are always communities of xerophytic shrubs or low trees (in many cases alien species, such as Amorpha fruticosa L., Ziziphus jujuba Mill. and Robinia pseudoacacia L.) that participate in the association without forming a full second layer (their cover abundance is less than 30%).

Retreating winter and strengthening autumn Mediterranean influence on extreme precipitation in the Southwestern Alps over the last 60 years

This article analyzes the large-scale circulations producing daily precipitation extremes in the Southwestern Alps and their trends from 1958 to 2017. We consider a high-resolution precipitation data set of 1 × 1 km2 and the weather patterns associated to the precipitation seasonal maxima at each grid point. The high-resolution allows us to analyze in details the atmospheric influences triggering seasonal maxima. Four influences are considered—the Atlantic influence, the Mediterranean influence, the northeast circulation and the Anticyclonic situation. We show that influences on maxima are very well organized in space but their organization depends on the season. Maxima are very mainly triggered by two types of influences in the region—the Atlantic influence and the Mediterranean influence. Trends in weather patterns producing maxima are also organized in space, with opposite trends for the Atlantic and the Mediterranean influences. The Mediterranean influence retreated very significantly over the period in winter and spring, while the Atlantic influence significantly extended further south. In autumn the Mediterranean influence strengthened where it was already dominant.

Reproductive Biology of Olive Trees (Arbequina cultivar) at the Northern Limit of Their Distribution Areas

In recent years, North-western Spain has experienced an increase in the cultivated area of olive trees. The main propitious areas for olive groves are the Miño and Sil basins, as a consequence of their Oceanic climate with Mediterranean influence. The objective of this study is to determine the characteristics of reproductive biology, phenological and aerobiological behaviour of olive trees in the most northerly new plantation areas of the Iberian Peninsula. The study was carried out in an olive grove growing Olea europaea L. cv. ‘Arbequina’ located in Quiroga (Lugo) from 2016 to 2018. The phenological observations were based upon the main growth stages following the Biologische Bundesanstalt Bundessortenamt and Chemical industry (BBCH) scale. To predict the onset of flowering, a thermal time model was used in order to quantify the chill requirements, and growing degree-days were applied to determine the heat requirement. The production, viability and germination rates of Olea pollen were evaluated from samples selected in nine individual trees for the phenological survey. The aerobiological study was conducted by means of a Hirst-type pollen trap located in the centre of the olive grove. The vegetative period of the olive tree in the study area lasted an average of 259 days. The important phenological stage 6 (flowering) was the shortest stage. An average of 704 Chilling Hours (CH) with a threshold of 2.5 °C was required to overcome the chilling period, 1139 Growing Degree Days (GDD) for the beginning of flowering, and 4463 GDD for harvest. The pollen production per anther was 82589 grains (± 14084 pollen grains), with a rate of 81% viability and 12% pollen tube germination. The main pollen season started on average on May 20th and ended on June 16th with an average duration of 27 days and an annual pollen integral of 833 pollen grains. The low pollen concentrations could be a consequence of the Northern location of the forest, in a bioclimatic transition zone between the Eurosiberian and the Mediterranean areas, at the limit of olive tree distribution.