To learn more about the map elements, please download the "Pan-European strategy for genetic conservation of forest trees"
This distribution map has been developed by the European Commission Joint Research Centre (partly based on the EUFORGEN map) and released under Creative Commons Attribution 4.0 International (CC-BY 4.0)
Caudullo, G., Welk, E., San-Miguel-Ayanz, J., 2017. Chorological maps for the main European woody species. Data in Brief 12, 662-666. DOI: https://doi.org/10.1016/j.dib.2017.05.007
The following experts have contributed to the development of the EUFORGEN distribution maps:
Fazia Krouchi (Algeria), Hasmik Ghalachyan (Armenia), Thomas Geburek (Austria), Berthold Heinze (Austria), Rudi Litschauer (Austria), Rudolf Litschauer (Austria), Michael Mengl (Austria), Ferdinand Müller (Austria), Franz Starlinger (Austria), Valida Ali-zade (Azerbaijan), Vahid Djalal Hajiyev (Azerbaijan), Karen Cox (Belgium), Bart De Cuyper (Belgium), Olivier Desteucq (Belgium), Patrick Mertens (Belgium), Jos Van Slycken (Belgium), An Vanden Broeck (Belgium), Kristine Vander Mijnsbrugge (Belgium), Dalibor Ballian (Bosnia and Herzegovina), Alexander H. Alexandrov (Bulgaria), Alexander Delkov (Bulgaria), Ivanova Denitsa Pandeva (Bulgaria), Peter Zhelev Stoyanov (Bulgaria), Joso Gracan (Croatia), Marilena Idzojtic (Croatia), Mladen Ivankovic (Croatia), Željka Ivanović (Croatia), Davorin Kajba (Croatia), Hrvoje Marjanovic (Croatia), Sanja Peric (Croatia), Andreas Christou (Cyprus), Xenophon Hadjikyriacou (Cyprus), Václav Buriánek (Czech Republic), Jan Chládek (Czech Republic), Josef Frýdl (Czech Republic), Petr Novotný (Czech Republic), Martin Slovacek (Czech Republic), Zdenek Špišek (Czech Republic), Karel Vancura (Czech Republic), Ulrik Bräuner (Denmark), Bjerne Ditlevsen (Denmark), Jon Kehlet Hansen (Denmark), Jan Svejgaard Jensen (Denmark), Kalev Jðgiste (Estonia), Tiit Maaten (Estonia), Raul Pihu (Estonia), Ülo Tamm (Estonia), Arvo Tullus (Estonia), Aivo Vares (Estonia), Teijo Nikkanen (Finland), Sanna Paanukoski (Finland), Mari Rusanen (Finland), Pekka Vakkari (Finland), Leena Yrjänä (Finland), Daniel Cambon (France), Eric Collin (France), Alexis Ducousso (France), Bruno Fady (France), François Lefèvre (France), Brigitte Musch (France), Sylvie Oddou-Muratorio (France), Luc E. Pâques (France), Julien Saudubray (France), Marc Villar (France), Vlatko Andonovski (FYR Macedonia), Dragi Pop-Stojanov (FYR Macedonia), Merab Machavariani (Georgia), Irina Tvauri (Georgia), Alexander Urushadze (Georgia), Bernd Degen (Germany), Jochen Kleinschmit (Germany), Armin König (Germany), Armin König (Germany), Volker Schneck (Germany), Richard Stephan (Germany), H. H. Kausch-Blecken Von Schmeling (Germany), Georg von Wühlisch (Germany), Iris Wagner (Germany), Heino Wolf (Germany), Paraskevi Alizoti (Greece), Filippos Aravanopoulos (Greece), Andreas Drouzas (Greece), Despina Paitaridou (Greece), Aristotelis C. Papageorgiou (Greece), Kostas Thanos (Greece), Sándor Bordács (Hungary), Csaba Mátyás (Hungary), László Nagy (Hungary), Thröstur Eysteinsson (Iceland), Adalsteinn Sigurgeirsson (Iceland), Halldór Sverrisson (Iceland), John Fennessy (Ireland), Ellen O'Connor (Ireland), Fulvio Ducci (Italy), Silvia Fineschi (Italy), Bartolomeo Schirone (Italy), Marco Cosimo Simeone (Italy), Giovanni Giuseppe Vendramin (Italy), Lorenzo Vietto (Italy), Janis Birgelis (Latvia), Virgilijus Baliuckas (Lithuania), Kestutis Cesnavicius (Lithuania), Darius Danusevicius (Lithuania), Valmantas Kundrotas (Lithuania), Alfas Pliûra (Lithuania), Darius Raudonius (Lithuania), Robert du Fays (Luxembourg), Myriam Heuertz (Luxembourg), Claude Parini (Luxembourg), Fred Trossen (Luxembourg), Frank Wolter (Luxembourg), Joseph Buhagiar (Malta), Eman Calleja (Malta), Ion Palancean (Moldova), Dragos Postolache (Moldova), Gheorghe Postolache (Moldova), Hassan Sbay (Morocco), Tor Myking (Norway), Tore Skrøppa (Norway), Anna Gugala (Poland), Jan Kowalczyk (Poland), Czeslaw Koziol (Poland), Jan Matras (Poland), Zbigniew Sobierajski (Poland), Maria Helena Almeida (Portugal), Filipe Costa e Silva (Portugal), Luís Reis (Portugal), Maria Carolina Varela (Portugal), Ioan Blada (Romania), Alexandru-Lucian Curtu (Romania), Lucian Dinca (Romania), Georgeta Mihai (Romania), Mihai Olaru (Romania), Gheorghe Parnuta (Romania), Natalia Demidova (Russian Federation), Mikhail V. Pridnya (Russian Federation), Andrey Prokazin (Russian Federation), Srdjan Bojovic (Serbia) , Vasilije Isajev (Serbia), Saša Orlovic (Serbia), Rudolf Bruchánik (Slovakia), Roman Longauer (Slovakia), Ladislav Paule (Slovakia), Gregor Bozič (Slovenia), Robert Brus (Slovenia), Katarina Celič (Slovenia), Hojka Kraigher (Slovenia), Andrej Verlič (Slovenia), Marjana Westergren (Slovenia), Ricardo Alía (Spain), Josefa Fernández-López (Spain), Luis Gil Sanchez (Spain), Pablo Gonzalez Goicoechea (Spain), Santiago C. González-Martínez (Spain), Sonia Martin Albertos (Spain), Eduardo Notivol Paino (Spain), María Arantxa Prada (Spain), Alvaro Soto de Viana (Spain), Lennart Ackzell (Sweden), Jonas Bergquist (Sweden), Sanna Black-Samuelsson (Sweden), Jonas Cedergren (Sweden), Gösta Eriksson (Sweden), Markus Bolliger (Switzerland), Felix Gugerli (Switzerland), Rolf Holderegger (Switzerland), Peter Rotach (Switzerland), Marcus Ulber (Switzerland), Sven M.G. de Vries (The Netherlands), Khouja Mohamed Larbi (Tunisia), Murat Alan (Turkey), Gaye Kandemir (Turkey), Gursel Karagöz (Turkey), Zeki Kaya (Turkey), Hasan Özer (Turkey), Hacer Semerci (Turkey), Ferit Toplu (Turkey), Mykola M. Vedmid (Ukraine), Roman T. Volosyanchuk (Ukraine), Stuart A'Hara (United Kingdom), Joan Cottrell (United Kingdom), Colin Edwards (United Kingdom), Michael Frankis (United Kingdom), Jason Hubert (United Kingdom), Karen Russell (United Kingdom), C.J.A. Samuel (United Kingdom).
Status of Quercus ilex conservation in Europe
Holm oak has high genetic and phonotypic variability across its range, with introgression between holm oak and kermes oak (Quercus coccifera) creating morphologically similar hybrids (Ortego, Bonal, and Muñoz, 2010; Raimondo et al., 2013). Populations in mainland Italy, Sicily, and Morocco have been shown to have high genetic diversity and some genetic similarities between them (Raimondo et al., 2013). This genetic variation can be retained for a long time as holm oak can live for centuries. Therefore, populations with old trees in recently fragmented habitats retain the genetic diversity present prior to fragmentation (Ortego, Bonal, and Muñoz, 2010). However, the same authors note that fragmentation has reduced gene flow and increased genetic drift and self-fertilization in young populations.
Five regions of genetic diversity have been identified in holm oak: the Aegean peninsula and Crete; Italy; North Africa; eastern Iberia and France; and western Iberia and France. However, some research also distinguishes the Balkan and south-western French populations as distinct groups (Vernesi et al., 2012).
There is very little genetic differentiation in adult populations, even in fragmented stands, but there is stronger differentiation in young trees, which has led to a pattern of spatial genetic structuring and isolation by distance in some holm oak populations (Ortego, Bonal, and Muñoz, 2010). Peripheral populations typically have lower heterozygosity and allelic richness than central populations, but some peripheral populations still maintain high genetic diversity (Vernesi et al., 2012). Even among geographically close populations differentiation is significant, with climatic features, such as soil depth, elevation, and humidity being correlated with genetic differentiation between populations (Vernesi et al., 2012).
Holm oak has restricted gene flow as it relies on birds and rodents to disperse acorns, which commonly spread the seeds less the 50 m from the tree (Ortego, Bonal, and Muñoz, 2010). This means forest fragmentation can severely limit the species’ gene flow. Holm oak can resprout easily after disturbances, creating an extensive clonal structure with many “clumps” derived from one tree (Ortego, Bonal, and Muñoz, 2010). These clonal structures are common in coppiced managed stands that stimulate resprouting (Ortego, Bonal, and Muñoz, 2010).
The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2024.
No available information.
The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2024.
Holm oak may be under threat of genetic loss from changes in population size and isolation resulting from human activity in forest and agricultural landscapes over centuries that has caused fragmentation of populations (Vernesi et al., 2012; Schirone, Vessella, and Varela, 2019). In Spain, holm oak was traditionally felled to provide firewood, charcoal, and timber or cleared to create open wooded landscapes for livestock and cereal production. This created different levels of forest fragmentation, ranging from continuous forest to isolated trees in farmland (Ortego, Bonal, and Muñoz, 2010). However, holm oak is now being replaced by faster-growing species or clear cut and is under threat from fires and overgrazing in Mediterranean coastal stands (Schirone, Vessella, and Varela, 2019).
Natural regeneration in holm oak is poor as propagation by forest owners is often through vegetative sprouting, which decreases genetic diversity (Schirone, Vessella, and Varela, 2019). This has resulted in a loss of intraspecific genetic diversity in holm oak in coppiced stands where short cutting cycles of 20 years are used (Ortego, Bonal, and Muñoz, 2010).
Genetic conservation programmes should prioritize the conservation of endangered and marginal populations and sample the genetic diversity of potential populations. This will allow the establishment of dynamic conservation units based on long-term autochthony, high biodiversity value, and location in ecologically diverse regions (Schirone, Vessella, and Varela, 2019).
Seed propagation for old and mature forests is the most suitable management method to maintain and increase genetic diversity and is, therefore, the best approach for conservation of the genetic resources of holm oak (Schirone, Vessella, and Varela, 2019). Cleared stands should also be revegetated with genetically diverse individuals, and coppices converted into old and mature forests as they contain greater genetic diversity (Ortego, Bonal, and Muñoz, 2010; Schirone, Vessella, and Varela, 2019). Hybridization should also be restricted as it could affect genetic diversity of holm oak stands, or change their adaptive potential (Schirone, Vessella, and Varela, 2019).
The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2024.
Genetic Characterisation of Quercus ilex and its GCUs
Availability of FRM
FOREMATIS
Quercus ilex - Technical guidelines for genetic conservation of Holm oak
Publication Year: 2019Seed propagation for high forests is the most suitable management method to maintain and increase genetic diversity and, therefore, the conservation of the genetic resources of the species. It is the most adequate regime for landscape protection, ornamental and recreational functionalities. High forest merits are also on the use of water, which is a special feature for Mediterranean regions where increasing human demands for water are expected together with climate change induced drought (Gracia, 2009).
Coppices for firewood production (coppicing every 30–40 years) usually host a large amount of the biodiversity of Mediterranean ecosystems, but reduce the genetic diversity of the coppiced species, in particular where up growing single stems per stump are not left. Therefore, the chance to convert coppices into high forests, through a gradual increase of the number of single stems per stump, should be considered. For instance, a coppice stand with a single stem per stump system, with long cycles (not less than 40 to 50 years) and a large number of seed-bearing trees (even >200), contributes to the regeneration of the population and the maintenance of the understory and favours the natural evolution of Q. ilex towards its climax situation (which is pure high forest).
Holm oak hybridizes with other oak species and hybridization may result in a loss or an increase of genetic diversity according to the concrete situation of the population or species evolution (Soltis & Soltis, 2009). Where populations for conservation of genetic resources are established in mixed oak- stands, hybridization monitoring is recommended, whenever possible through genomics, transcriptomics and progeny testing.
Since limited genetic information about Q. ilex is available, it is recommended that genetic conservation programmes start with the following objectives: conservation of endangered, marginal populations and habitats of Q. ilex; sampling the genetic diversity; establishment of Dynamic Conservation Units based on long term autochthony, high biodiversity value and location in ecologically diverse regions of large populations (> 1000 individuals).
Seed propagation for high forests is the most suitable management method to maintain and increase genetic diversity and, therefore, the conservation of the genetic resources of the species. It is the most adequate regime for landscape protection, ornamental and recreational functionalities. High forest merits are also on the use of water, which is a special feature for Mediterranean...
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Mediterranean Oaks Network: Report of the first meeting
Social Broadleaves Network: Report of the fifth meeting (Temperate Oaks and Beech network)
Social Broadleaves Network: Report of the third meeting
Social Broadleaves Network: Report of the second meeting
Social Broadleaves Network: Report of the first meeting
Contacts of experts
NA
Further reading
Ortego, J. and Bonal, R. 2010. Natural hybridisation between kermes (Quercus coccifera L.) and holm oaks (Q. ilex L.) revealed by microsatellite markers. Plant Biology, 12(1): 234–238.
References
Ortego, J., Bonal, R., and Muñoz, A. 2010. Genetic consequences of habitat fragmentation in long-lived tree species: the case of the Mediterranean holm oak (Quercus ilex, L.). Journal of Heredity, 101(6): 717–726.
Raimondo, F.M., Scialabba, A., Guarino, R., and Spallino, R.E. 2013. Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae). Flora Mediterranea, 23: 245–253.
Schirone, B., Vessella, F., and Varela, M.C. 2019. EUFORGEN Technical Guidelines for genetic conservation and use for holm oak (Quercus ilex). Bonn, Germany, European Forest Genetic Resources Programme. 6 pages.
Vernesi, C., Rocchini, D., Pecchioli, E., Neteler, M., Vendramin, G.G., and Paffetti, D. 2012. A landscape genetics approach reveals ecological-based differentiation in populations of holm oak (Quercus ilex L.) at the northern limit of its range. Biological Journal of the Linnean Society, 107(2): 458–467.
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