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Platypus cylindrus is an important wood borer of cork oak trees (Quercus suber) in the Mediterranean region, namely Portugal, Morocco and Algeria where its presence has drastically increased in the past few decades. On the contrary, the insect is not a relevant pest in Tunisia. The aim of this work is to analyze morphological and genetic differences among Tunisian and Portuguese populations in order to understand their role in the diverse population dynamics (e.g., aggressiveness) of the insect. The information could be used as a novel tool to implement protective measures. Insects were collected from cork oak stands in Tunisia (Ain Beya, Babouch and Mzara) and Portugal (Chamusca and Crato). Morphological traits of female and male mycangial pits were determined, using scanning electron microscopy but no significant differences were found. Genetic differences were analyzed using nuclear (internal simple sequence repeat polymerase chain reaction) and mitochondrial (cytochrome oxidase I (COI)) molecular markers. The results showed a very low level of intraspecific polymorphism and genetic diversity. The alignment of COI sequences showed high percentage of identical sites (99%) indicating a very low variation in nucleotide composition. Other variables related with the ecology of the insect and its associated fungi must be studied for a better understanding of the differences in the insect population's dynamic in Mediterranean countries. [ABSTRACT FROM PUBLISHER]

Abstract: Quercus suber and Quercus ilex trees are major elements of Mediterranean landscapes, which are threatened by the increasing water deficits related to climate change. To contribute to the understanding of the capacity of these oaks to withstand severe drought we assessed the vulnerability to xylem embolism and the anatomical traits in current-year shoots. Data were collected in mature trees at two sites, in central/coastal and southern/inland Portugal. In situ safety margins to hydraulic failure were evaluated from long-term predawn and midday leaf water potential records. Results showed that xylem vulnerability to embolism was similar in Q. ilex and Q. suber. The 50% loss in hydraulic conductivity (Ψxyl ,50 PLC ) was observed at xylem water potentials of −2.9 and −3.2MPa in shoots of Q. suber and Q. ilex, respectively. Values of mean vessel diameter of Q. suber shoots at both sites suggest an intra-species adaptation to the local water availability, with larger vessels at the more mesic site. In situ hydraulic safety margins observed in shoots showed that, even during the driest periods, both oaks lived comfortably above the most critical embolism thresholds. However, the hydraulic safety margins were narrower in the driest site. Results are relevant to the understanding of survival, growth, and functional behaviour of evergreen oaks in Mediterranean climates, under recurrent/seasonal drought conditions. [Copyright &y& Elsevier]

Changes in land use/land cover are a major driver of biodiversity change in the Mediterranean region. Understanding how animal populations respond to these landscape changes often requires using landscape mosaics as the unit of investigation, but few previous studies have measured both response and explanatory variables at the land mosaic level. Here, we used a "whole-landscape" approach to assess the influence of regional variation in the land cover composition of 81 farmland mosaics (mean area of 2900 ha) on the population density of a threatened bird, the little bustard (Tetrax tetrax), in southern Portugal. Results showed that ca. 50% of the regional variability in the density of little bustards could be explained by three variables summarising the land cover composition and diversity in the studied mosaics. Little bustard breeding males attained higher population density in land mosaics with a low land cover diversity, with less forests, and dominated by grasslands. Land mosaic composition gradients showed that agricultural intensification was not reflected in a loss of land cover diversity, as in many other regions of Europe. On the contrary, it led to the introduction of new land cover types in homogenous farmland, which increased land cover diversity but reduced overall landscape suitability for the species. Based on these results, the impact of recent land cover changes in Europe on the little bustard populations is evaluated. [ABSTRACT FROM AUTHOR]

The Mediterranean Basin is recognized for its high levels of species richness, rarity and endemicity. Our main aim was to evaluate the relative effects of environmental and spatial variables and their scale-specific importance on beta diversity patterns along a gradient of mediterraneity, using spiders as a model group. This study was carried out in 18 coastal dune sites along the Portuguese Atlantic coast. This area encompasses 445 km and comprises two distinct biogeographic regions, Eurosiberian (northern coast) and Mediterranean (centre and south). A forward selection procedure was carried out to select environmental and spatial variables responsible for determining beta diversity patterns. Variation partitioning and principal coordinates of neighbour matrices (PCNM) were used to estimate the contribution of pure environmental and pure spatial effects and their shared influence on beta diversity patterns and to estimate the relative importance of environmental structured variation and pure spatial variation at multiple spatial scales. Climate, ground vegetation dune cover and area were selected by a forward selection procedure. The same procedure identified three PCNM variables, all corresponding to large and medium spatial scales. Variation partitioning revealed that 46.1% of the variation of beta diversity patterns was explained by a combination of environmental and PCNM variables. Most of this variation (42.5%) corresponded to spatial variation (environmental spatially structured and pure spatial). Climate and vegetation structure influences were predominant at the PCNM1 and PCNM3 scales, while area was more important at the intermediate PCNM2 scale. Our study revealed that beta diversity of spiders was primarily controlled by a broad-scale gradient of mediterraneity. The relative importance of environmental variables on the spider assemblage composition varied with spatial scale. This study highlights the need of considering the scale-specific influence of niche and neutral processes on beta diversity patterns. [ABSTRACT FROM AUTHOR]

Intensive fieldwork has been undertaken in Portugal in order to develop a standardized and optimized sampling protocol for Mediterranean spiders. The present study had the objectives of testing the use of semi-quantitative sampling for obtaining an exhaustive species richness assessment of spiders and testing the effects of day, time of day, collector and sampling method on the collected species richness and composition of a Mediterranean scrubland. The collecting summed 224 samples corresponding to one person-hour of effective fieldwork each. In total, 115 species were captured, of which 110 were recorded inside a delimited one-hectare plot, corresponding to more than 70% of the about 160 estimated species. Although no estimator reached the asymptote, the Michaelis-Menten curve behaviour indicates that the estimated richness should be accurate. Most different sampling approaches (day, time of day, collector and sampling method) were found to influence richness, abundance or composition of the samples to some extent, although sampling method had the strongest influence whereas “collector” showed no effect at all. The results support the idea that the only variables that need to be controlled in similar protocols are the sampling methods and the time of day when each method is executed. We conclude that populations in structurally simple habitats present narrower peaks of adult abundance, which implies higher percentages of juveniles in samples. Finally, results also indicate that habitats with a relatively simple structure like scrublands may require as much sampling effort, in order to reach similar proportions of captured species in relation to the estimated richness, as habitats that are much more complex. [ABSTRACT FROM AUTHOR]

Summary: Mediterranean evergreen oak woodlands of southern Portugal (montados) are savannah-type ecosystems with a widely sparse tree cover, over extensive grassland. Therefore, ecosystem water fluxes derive from two quite differentiated sources: the trees and the pasture. Partitioning of fluxes according to these different sources is necessary to quantify overall ecosystem water losses as well as to improve knowledge on its functional behaviour. In southern Iberia, these woodlands are subjected to recurrent droughts. Therefore, reaction/resilience to water stress becomes an essential feature of vegetation on these ecosystems. Long-term tree transpiration was recorded for 6 years from a sample of holm oak (Quercus ilex ssp. rotundifolia) trees, using the Granier sap flow method. Ecosystem transpiration was measured by the eddy covariance technique for an 11-month period (February to December 2005), partly coincident with a drought year. Pasture transpiration was estimated as the difference between ecosystem (eddy covariance) and tree (sap flow) transpiration. Pasture transpiration stopped during the summer, when the surface soil dried up. In the other seasons, pasture transpiration showed a strong dependence on rainfall occurrence and on top soil water. Conversely, trees were able to maintain transpiration throughout the summer due to the deep root access to groundwater. Q. ilex trees showed a high resilience to both seasonal and annual drought. Tree transpiration represented more than half of ecosystem transpiration, in spite of the low tree density (30 trees ha−1) and crown cover fraction (21%). Tree evapotranspiration was dominated by transpiration (76%), and interception loss represented only 24% of overall tree evaporation. [Copyright &y& Elsevier]

Late Toarcian–Aalenian brachiopod assemblages recorded in different basins located in and around Iberia present a pattern of spatial and temporal distribution which enables two palaeobiogeographic biochoremas to be differentiated: the Iberian-Atlantic District (IAD), which includes the Lusitanian Basin, Asturias and the Basque-Cantabrian Basin, on one hand, and the Iberian-Mediterranean District (IMD); the latter basically comprises the Iberian Range and the Tortosa Platform of the Catalonian Basin. Changes in the composition of the assemblages throughout the stratigraphical interval studied have enabled three main stages characterizing each palaeobiochorema to be recognized. The first two assemblages reflect gradual individualization and isolation, with frequent endemisms. These two stages correspond to the IAD1, IAD2, IMD1 and to the IMD2 assemblages respectively. As from the Pseudoradiosa Chronozone, and during the Aalensis and Opalinum chronozones, an increase in communication between the two districts can be observed, as well as between these and other remote areas. This stage is represented by the IAD3 and the IMD3 assemblages. Some of the brachiopods colonizing the districts are widely dispersed due to their capacity for expansion: they have been found in other Tethysian basins. Other species are exclusive to the district basins and appear to have originated in the areas close to them. For the latter species the existence of two different “evolutionary factories” is proposed: one that supplies species to the IAD, mainly from generic stocks as Neozeilleria , Soaresirhynchia or Praemonticlarella ; and another for the species reaching the basins of the IMD, clearly shared by other European and North African basins. The Atlantic “evolutionary factory” remains active until the Aalenian and part of the Early Bajocian, while the Mediterranean is diluted since the Aalenian. [ABSTRACT FROM AUTHOR]

Climate change is impacting locally adapted species such as the keystone tree species cork oak (Quercus suber L.). Quantifying the importance of environmental variables in explaining the species distribution can help build resilient populations in restoration projects and design forest management strategies. Using landscape genomics, we investigated the population structure and ecological adaptation of this tree species across the Mediterranean Basin. We applied genotyping by sequencing and derived 2,583 single nucleotide polymorphism markers genotyped from 81 individuals across 17 sites in the studied region. We implemented an approach based on the nearest neighbour haplotype 'coancestry' and uncovered a weak population structure along an east-west climatic gradient across the Mediterranean region. We identified genomic regions potentially involved in local adaptation and predicted differences in the genetic composition across the landscape under current and future climates. Variants associated with temperature and precipitation variables were detected, and we applied a nonlinear multivariate association method, gradient forest, to project these gene-environment relationships across space. The model allowed the identification of geographic areas within the western Mediterranean region most sensitive to climate change: south-western Iberia and northern Morocco. Our findings provide a preliminary assessment towards a potential management strategy for the conservation of cork oak in the Mediterranean Basin., (© 2021 European Society For Evolutionary Biology.)