Climatic niche and neutral genetic diversity of the six Iberian pine species: a retrospective and prospective view

Quaternary climatic fluctuations have left contrasting historical footprints on the neutral genetic diversity patterns of existing populations of different tree species. We should expect the demography, and consequently the neutral genetic structure, of taxa less tolerant to particular climatic extremes to be more sensitive to long-term climate fluctuations. We explore this hypothesis here by sampling all six pine species found in the Iberian Peninsula (2464 individuals, 105 populations), using a common set of chloroplast microsatellite markers, and by looking at the association between neutral genetic diversity and species-specific climatic requirements. We found large variation in neutral genetic diversity and structure among Iberian pines, with cold-enduring mountain species (Pinus uncinata, P. sylvestris and P. nigra) showing substantially greater diversity than thermophilous taxa (P. pinea and P. halepensis). Within species, we observed a significant positive correlation between population genetic diversity and summer precipitation for some of the mountain pines. The observed pattern is consistent with the hypotheses that: (i) more thermophilous species have been subjected to stronger demographic fluctuations in the past, as a consequence of their maladaptation to recurrent glacial cold stages; and (ii) altitudinal migrations have allowed the maintenance of large effective population sizes and genetic variation in cold-tolerant species, especially in more humid regions. In the light of these results and hypotheses, we discuss some potential genetic consequences of impending climate change

Amber imitation? Two unusual cases of Pinus resin-coated beads in Iberian Late Prehistory (3rd and 2nd millennia BC)

A group of beads from the artificial cave of La Molina (Lora de Estepa, Sevilla) and Cova del Gegant (Sitges, Barcelona) were made from a biogenic raw material and intentionally covered by a layer of resin. This is the first time this type of treatment has been documented on elements of adornment in the Late Prehistory of the Iberian Peninsula. The composition and nature of the coatings are analysed and the symbolic role of such alterations and imitations of prehistoric adornments is discussed.Ministerio de Economía y Competitividad HAR2012- 34620, HAR2017-83474-

First record of the sawfly family Xyelidae (Hymenoptera) from Malta

Xyela cf. altenhoferi Blank, 2013 is recorded from Buskett (Malta). Its host is Pinus halepensis. This is the first species of the sawfly family Xyelidae to be found in the Maltese Islands.peer-reviewe

A global model for the combustion of gas mixtures released from forest fuels

International audienc

Pauesia silana Tremblay, 1969 a parasitoid of Cinara-aphids on Conifers in Malta (Hymenoptera: Braconidae: Aphidiinae)

Pauesia silana is recorded for the first time from Malta and the Lefkada and Meganissi islands in Greece. From Malta, the species was reared from Cinara palaestinensis on Pinus halepensis from material collected from Buskett. From the Greek islands, the species was collected on Cinara sp. on the same mentioned hostplant. The new record contributes to the information on its distribution, hosts and plant associations in the Mediterranean area.peer-reviewe

Ageing of resin from Pinus species assessed by infrared spectroscopy

Resins obtained from Pinus genus species have been widely used in very different fields throughout history. As soon as the resins are secreted, molecular changes start altering their chemical, mechanical and optical properties. The ageing processes are complex, and the chemical and structural changes associated with resin degradation are not yet fully known. Many questions still remain open, for instance changes happening in pimaranes, one of the two diterpenoid constituents of the resin. A systematic study of the ageing process of Pinus resins is done through Fourier transform infrared spectroscopy (FTIR) using chemical standards and complementing the obtained results with gas chromatography coupled to mass spectrometry (GC/MS) analysis when necessary. Moreover, long-term degradation processes are also investigated through the analysis of a selection of dated historical resins. This study overcomes the limitations of GC/MS and brings new information about the reactions and interactions between molecules during Pinus resin ageing processes. It also provides information about which bonds are affected and unaffected, and these can be used as specific markers of the degradation and of the resins themselves. [Figure not available: see fulltext.]Peer ReviewedPostprint (author's final draft

Potential climatic influence on the maximum stand carrying capacity of 15 Mediterranean conifers and broadleaves

Las proyecciones de cambio climático para la cuenca del Mediterráneo predicen un incremento continuo en episodios de sequía y calor extremos, afectando a la dinámica, estructura y composición de las masas forestales. En este contexto, resulta fundamental comprender cómo el clima influye en la relación tamaño-densidad máxima (recta de autoclareo) de estas masas con el fin de diseñar actuaciones de gestión forestal sostenible adaptadas a este nuevo escenario. Este estudio pretende avanzar en esta línea, analizando los potenciales impactos del clima en el Índice de Máxima Densidad (SDImax) de 15 especies forestales pertenecientes a los géneros Pinus, Fagus y Quercus. Para ello se utilizaron las bases de datos del Tercer Inventario Forestal Nacional Español (IFN3) y WorldClim. En primer lugar, se ajustaron rectas de autoclareo básicas mediante regresión cuantílica y se estimaron nuevos valores SDImax de referencia por especie. En un segundo paso, se seleccionaron 35 variables climáticas anuales y periódicas para ajustar rectas de autoclareo dependientes del clima. El mejor modelo climáticodependiente fue seleccionado para cada especie basándonos en el Indice de Información de Akaike con el fin de analizar las tendencias generales y específicas en la variación de SDImax. Para todas las especies de estudio, la influencia del clima sobre el SDImax fue significativa. Los resultados obtenidos mostraron una tendencia común en la variación de SDImax, con valores más pequeños vinculados a condiciones más secas y cálidas, lo que sugiere reducciones potenciales del stock de estas especies bajo futuros escenarios climáticos. En oposición a esta tendencia, el modelo de Pinus nigra sugiere que inviernos más suaves como efecto de incrementos en temperaturas mínimas podrían beneficiar a las especies en zonas de montaña. En general, el estrés hídrico (expresado a través del Indice De Martonne) fue un factor determinante afectando al SDImax de Fagus, mientras que cambios en las temperaturas de primavera y verano explicaron las variaciones SDImax de las especies del género Quercus. Las especies de Pinus se vieron indistintamente afectadas por potenciales variaciones de temperatura y humedad. Todos los modelos climático-dependientes seleccionados mejoraron los modelos básicos y los modelos ajustados en estudios similares, como aquellos que utilizan el Índice de Martonne como variable climática independiente. Nuestros hallazgos destacan la necesidad de utilizar variables climáticas periódicas para caracterizar mejor los impactos climáticos en el SDImax. Los modelos presentados en este estudio permitirán obtener estimaciones más precisas de la máxima densidad admisible por diferentes especies de coníferas y frondosas, proporcionando una herramienta avanzada para la gestión forestal sostenible de masas puras y mixtas mediterráneas bajo diferentes escenarios de cambio climático.Climate change projections for the Mediterranean basin predict a continuous increment in extreme drought and heat episodes, affecting forest dynamics, structure and composition. Understanding how climate influences the maximum size-density relationship (MSDR) is therefore critical to design adaptative silvicultural guidelines based on the potential stand carrying capacity of tree species. With this aim, data from the Third Spanish National Forest Inventory (3NFI) and WorldClim databases were used to analyze climate related variations of the maximum stand carrying capacity for 15 species from the Pinus, Fagus and Quercus genus. First, basic MSDR were fitted using linear quantile regression and observed size-density data from monospecific 3NFI plots. Reference values of maximum stocking, expressed as SDImax, were estimated by species. In a second step, climatedependent MSDR models including 35 different annual and seasonal climatic variables were fitted. The best climate-dependent MSDR model was selected by species according to the Akaike Information Criteria in order to analyze general and species-specific trends in the SDImax variation. Results showed a common trend across species in SDIgenus variation with smaller SDImax values linked to drier and warmer conditions, suggesting potential reductions of the maximum stocking for this species based on projected climatic scenarios. Opposed to this trend, results for Pinus nigra suggest that milder winters as effect of increments in minimum temperatures could beneficiate mountainous species. Humidity (expressed as the De Martonne Index) was found as key driver affecting SDImax of Fagus species, since changes in spring and summer temperatures explained SDImax variations of Quercus species. Pinus species were indistinctively affected by temperature and water stress. All the selected climate-dependent models improved the goodness of fit over the basic and the business-as-usual models including the De Martonne Index as independent climatic variable. Our findings highlight the importance of using specific climatic variables to better characterize climatic impacts on the MSDR. Models presented in this study will allow to obtain more precise estimations of the maximum stocking for different coniferous and broadleaved species, providing an advanced tool for managing Mediterranean pure and mixed forests under different scenarios of climate change.Máster en Gestión Forestal basada en Ciencia de Dato