Archive for the ‘Science we create’ Category

The Forest Genetics Laboratory has a new site, where our contributions in conferences and meetings can be found. Posters, presentations and full papers can be downloaded in pdf format or as picture files. Most presentations can be viewed via Slideshare.

http://utopia.duth.gr/~apapage/Lab/conferences.html

Το Εργαστήριο Δασικής Γενετικής κοινοποιεί μια νέα ιστοσελίδα που περιέχει όλες τις συμμετοχές του εργαστηρίου σε συνέδρια και συναντήσεις από το 2002 μέχρι σήμερα. Πρόκειται για πόστερ, παρουσιάσεις και πλήρεις εργασίες που μπορείτε να δείτε μέσω του slideshare ή να κατεβάσετε σε μορφή pdf ή εικόνας.

Advertisement

Παρουσίαση από το συνέδριο της ΕΕΕΓΒΦ στην Ορεστιάδα το 2006. Παρουσιάζεται μια ιδέα για μέτρηση των επιπέδων ομομειξίας με μια “διόρθωση” των δεδομένων ετεροζυγωτίας σε δύο γενιές.

Από τις παλιές πρώτες επικοινωνίες του εργαστηρίου.

Image Δασολογικό Συνέδριο στη Δράμα (2005).

Η γενετική ποικιλότητα των δασικών ειδών είναι ιδιαίτερα σημαντική για την προσαρμογή των δασικών πληθυσμών στο ολοένα μεταβαλλόμενο περιβάλλον τους. Η μεταφορά της γενετικής ποικιλότητας από τη μία γενιά στην άλλη διασφαλίζει την προσαρμοστικότητα των δασικών πληθυσμών στο διηνεκές. Το σύνολο των σπόρων που παράγεται από έναν πληθυσμό δασικών φυτών έχει συγκεκριμένη γενετική δομή, που εξαρτάται από τη γενετική ποικιλότητα των δέντρων  γονέων και από το αναπαραγωγικό σύστημα. Οι ως τώρα έρευνες του αναπαραγωγικού συστήματος των δασικών ειδών έχουν γίνει κυρίως θεωρώντας την απόσταση μεταξύ των δέντρων ως την πιο βασική παράμετρο επηρεασμού της ικανότητας σταυρογονιμοποίησης των δέντρων σε μια συστάδα. Στην παρούσα εργασία εξετάζονται δύο περιπτώσεις, όπου η απόσταση δρα διαφορετικά. Στο μεσογειακό κυπαρίσσι  (Cupressus sempervirens) βρέθηκε μείωση της ικανότητας σταυρογονιμοποίησης σε αραιές συστάδες, σε σχέση με άλλες πιο πυκνές, ενώ αντίστροφα στον ίταμο (Taxus baccata) η μεγάλη απόσταση των δέντρων σπορέων από τα αρσενικά δέντρα συνέβαλε στην αύξηση της σταυρογονιμοποίησης. Η διαφορά αυτή ανάμεσα στις δύο περιπτώσεις οφείλεται σε άλλους ενδοσυσταδικούς παράγοντες, πλην της απόστασης, όπως είναι η μείξη των ειδών σε ένα δάσος και η ηλικία και το μέγεθος των δέντρων. Χρειάζεται λοιπόν να θεωρήσουμε ένα σύνολο παραγόντων, προκειμένου να περιγράψουμε τη δυνατότητα ενός πληθυσμού να μεταφέρει τη γενετική του ποικιλότητα στην επόμενη γενιά. Η πληροφορία αυτή είναι ιδιαίτερα σημαντική για την επιλογή δέντρων για συλλογή σπόρων, αλλά και των κατάλληλων δασοκομικών μέτρων σε διαχειριζόμενα δάση και δάση ιδιαίτερου οικολογικού ενδιαφέροντος.

by Aristotelis C. Papageorgiou and Dimitrios Kasimiadis

Full paper published in figshare: http://figshare.com/articles/The_genetic_component_of_biodiversity_in_forest_ecosystems/157195

Also available through figshare:

http://figshare.com/articles/Genetic_implications_of_forest_management_in_the_Mediterranean/157167

Mediterranean forests are characterized by high complexity and biological richness at all levels. Genetic diversity of Mediterranean forest species has been found to be higher than the one of central and northern Europe. It is important for the maintenance of forest cover and the adaptation of forests under adverse conditions towards environmental change. Genetic diversity in the Mediterranean forests has been shaped by the climatic and the geographical history of the region. However, the most important factor influencing diversity is the presence of human in the region. The impact of forest management techniques and other human activities on genetic diversity is analyzed. Sustainable forest management in the Mediterranean should take this information in account and include measures for the maintenance of genetic diversity of forest species. This will then secure the long-term character of forestry in the region and the production of goods and services for the society.

Beech has a broad European expansion and builds its southern most populations in Greece. Three polymorphic cpDNA microsatellite primers were used to describe the variation patterns of this tree in 40 populations. As many as 13 haplotypes were identified. Most of the variation was distributed among populations, but a considerable variation was also observed within some populations. No strong spatial structure was detected suggesting complex postglacial migration patterns. Possible explanations include the existence of several separated refugia in the region, the recolonization of mountains from different beech lineages and the formation of an introgression zone between two different beech subspecies in the broader area of Rodopi.

Παρουσίαση του Ν.Γ. Ηλιάδη στο συνέδριο «Οικολογία και ∆ιατήρηση της Βιοποικιλότητας», Ιωάννινα 2006.

Ο Κυπριακός κέδρος (Cedrus brevifolia) είναι ένα από τα τέσσερα είδη κέδρου που φύονται σήμερα. Είναι ενδημικό είδος της χλωρίδας της Κύπρου και απαντάται σε έναν και μόνο πληθυσμό στο δάσος Πάφου. Το έντονο ανάγλυφο της περιοχής, σε συνδυασμό με τις διάφορες οικοτυπικές δομές που σχηματίζονται συμβάλουν ώστε να διαχωριστεί ο πληθυσμός αυτός σε πέντε κύρια υποσύνολα. Σε αυτές τις ομάδες έγινε δειγματοληψία σε 700 συνολικά άτομα. Η χρήση τεσσάρων μικροδορυφορικών εκκινητών σε πυρηνικό DNA (n-SSR) παρουσίασαν σημαντικό αριθμό αλληλομόρφων (62), αποτυπώνοντας τη γενετική ποικιλότητα και διαφοροποίηση μεταξύ και ανάμεσα στα υποσύνολα πληθυσμού. Η αποτύπωση αυτή μας έδωσε διευκρινιστικές εικόνες για τα μέτρα που πρέπει να ληφθούν ώστε να υπάρξει μια αειφόρος διαχείριση και προστασία του είδους τόσο εντός, όσο και εκτός των φυσικών ορίων εξάπλωσης του.

Παρουσίαση που έγινε στην ημερίδα “Κλιματική Μεταβολή και Δάση” στις 5 Ιουνίου 2012 στο Ινστιτούτο Μεσογειακών Δασικών Οικοσυστημάτων και Τεχνολογίας Δασικών Προϊόντων, Αθήνα.

Image

by Aristotelis C. Papageorgiou

A presentation during the IUCN / WWF workshop on “Adaptation to climate change in Mediterranean forest conservation and management” Athens, April 14-16 2008

 

http://figshare.com/articles/Mediterranean_forest_genetic_diversity_and_adaptive_conservation_strategies/155662

 

Genetic diversity and the genetic system of a forest population

Biodiversity is clearly classified at three levels (genes, species and ecosystems) in almost all conservation policy documents and strategies and the importance of its genetic component for the adaptation and survival of the other two components is broadly recognized. However, genetic diversity is usually a small part of global, regional and local biodiversity conservation plans and strategies, mainly due to the practical difficulty for its description and quantification. At the same time, a major misunderstanding occurs, as most stakeholders and several scientists consider an expensive laboratory genetic inventory as the primary necessity prior any conservation decision and frequently consider the genes recorded in the laboratories as the target for future conservation activities. However, the role of genetic research in conservation is not to assess genetic variation per se, but rather to describe the parameters that shape genetic diversity, to identify threats, to model scenarios and to monitor the results of conservation measures.

More than maintaining genetic diversity of species in an ecosystem, it is important to maintain the mechanisms that produce high levels of diversity and connect subsequent generations with each other. This “genetic system” includes all evolutionary forces that act on a certain forest population and its function secures adaptability in the future.

Mediterranean forest genetic diversity and climate change

Mediterranean forests are characterized by high biological diversity at all levels. Mediterranean populations of tree species having a broader European expansion are genetically more diverse than populations located in northern latitudes. Populations and species often have a patchy distribution and are highly differentiated. At the same time, several species have a large and extensive distribution over different environments. The reasons for this genetic richness are the mountainous relief that forces species to adopt under different environmental conditions, the geographical location of the Mediterranean basin that allows migration between continents and the existence of important glacial refugia. While Mediterranean forests are rich in terms of genetic diversity, at the same time they are highly endangered due to the pressure of human activities since thousands of years. Furthermore, climate change scenarios show that the Mediterranean basin will suffer most from global warming and that the forests of the region will face severe survival problems.

Climate change is expected to have direct impact on forests in the Mediterranean, where trees will need to survive under severe environmental conditions and their populations will be forced to react evolutionary and adapt or migrate. Yet, some indirect impacts can act faster and have more significant effects on forest populations; change of climatic conditions will probably cause wildfires and large outbreaks of insects and disease. At the same time, social and economic changes caused by climate change can increase pressures on forests. Deforestation will lead to extinction of rare species having a small expansion. Tree species with larger distribution range will lose valuable populations and their locally adopted genetic structures. At the same time, when parts of a species range will be missing, fragmentation will occur, which will gradually lead to loss of diversity and extinction.

Tree populations having initially high levels of genetic diversity may adapt under the new climatic conditions. Yet, due to severity of the climate change, populations are expected to reduce their size and density, where genetic diversity can be reduced due to stochastic events, drift or inbreeding. At the same time, tree populations will need to specialize in the new conditions so much, that the genetic diversity in total and the adaptability in future changes will decline.

Climate change may also shift the limits of geographical range of plants, as it happened during the interglacial periods of the past. Populations that manage to migrate through seeds to the north or to move higher on the mountains experience founder effects and bottlenecks, as only a sample of their initial genetic pool is represented in the new populations. This can lead to loss of genetic diversity and future adaptability. However, it seems that migration will not be easy for plants in the Mediterranean, since human settlements, infrastructure and activities have already fragmented the natural areas and it seems unlikely that seeds will be able to spread gradually to new directions. Furthermore, migration of plants is a very slow process and the expected changes of climatic conditions in the Mediterranean will be rapid, leaving not enough time for natural evacuation of plant populations.

Adaptive conservation and management strategies

We have reasons to worry about the effects of climate change on Mediterranean forest populations, but at the same time we hope that the high genetic diversity of these populations will manage to lead to new adaptations, as it happened with some of these species in the past. Since deforestation is not an option and migration is rather problematic, we should focus how to develop efficient conservation and adaptive management strategies for the Mediterranean forests. Priority in such strategies should be the maintenance and the enhancement of the function of the genetic system that secures the transfer of genetic diversity from one generation to the other and allows evolution to take place.

Strategies for adaptive conservation and management of Mediterranean forests can take place in situ or ex situ. In situ strategies receive an increased attention, as they are more dynamic and allow the forest populations to evolve on site. As far as managed forests are concerned, most management approaches in the Mediterranean are imported from Central Europe, where forestry tradition is much older. These plans need to be adjusted to the Mediterranean conditions, to extend the targeted marketed and non-marketed values and to include all types of wild terrestrial ecosystems, not only productive forests in terms of timber. Emphasis should be given in the avoidance of measures that disturb the genetic system of forest populations. In order to secure pollen and seed movement, fragmentation of forests and low forest density should be avoided. Connectivity between forests should be maintained or restored. Restoration activities should focus in the protection of natural regeneration and where planting occurs, the used material should derive from local seed. Besides management, climate refugia and primary forests should be given priority for protection, mainly through networks of connected protected areas, including the main forest species and their ecotypes.

However, even the best adaptive management strategies will not be able to prevent the loss of species or populations that will not be able to adapt. For this reason, we need to develop ex situ measures for the maintenance of genetic diversity. Frequent and representative collections of seed for the main and most threatened forest tree species should be prioritized. These can be maintained in gene banks, plantations and can contribute to the increase of the genetic base of natural populations through the creation of seed orchards that will provide variable seed for restoration activities. Other measures for conserving local adaptations would be to evacuate certain areas of the south and create copies of populations further in the north. This however is rather complicated, very expensive and can occur only for a few populations. It is probably better to promote management strategies for the existing forests that do not alter the dynamics of the genetic system and allow pollen and seed movement with natural regeneration.

The development of adaptive management and conservation strategies needs effort and collaboration from different stakeholders. A new forest management approach, adjusted to the Mediterranean conditions and focused on the maintenance of natural processes, should be developed and implemented. At the same time, the importance of forests for the communities and settlements should be broadly recognized and an effective forest protection framework should be established.

Mediterranean forests have accumulated an important adaptation potential through different geological and climatic periods. The best strategy against climate change is to protect and manage them, in a way that the adaptation mechanisms will continue their function.

Poster presented during the Systematics Conference 2008, Göttingen, Germany. Download from figshare: http://figshare.com/articles/Patterns_of_genetic_diversity_of_Fagus_sylvatica_L_in_Rodopi_Mountains_of_N_E_Greece/154579

 Image

The taxonomic classification of European beech has been lately subject of long scientific discussions. Genetic variation at AFLPs, chloroplast microsatellites and variation in leaf morphology have been analysed in four populations of F. sylvatica in the greek Rodopi Mountains. The analysis of morphological traits reveals differences between the western and the eastern part of the Rodopi Mountains. Moreover, high levels of haplotype diversity were observed within populations, while in central and western Europe no variation at cpDNA markers was detected. Clinal variation patterns have occurred at both morphological and molecular markers, with the variation increasing from the west to the east. Differentiation among populations was found, as expected, stronger at maternaly inherited cpDNA. The results obtained in this study, can be explained either by considering the greek Rodopi an introgression zone between subspecies sylvatica and subspecies orientalis or by the existance of a main glacial refugial area. These scenarios are not mutually exclusive.

by Theodoros Mouratidis, Seraphim Hatziskakis, Nicolas George Eliades, Ioannis Tsiripidis, Reiner Finkeldey, Aristotelis C. Papageorgiou

This study aims at the description of beech postglacial movement within a mountain. The selected mountain Paggeo is isolated, while beech forms an altitudinal continuum for more than 1000m. Previous genetic studies have indicated the possible presence of a glacial refugium in the broader region. Seven sub-populations were sampled, in order to describe the structure of this refugial population. Three cpDNA microsatellite primer pairs were used. A high variety of haplotypes and a significant differentiation among sub-populations was detected. The results indicate that besides the refugial lineage on the north side of the mountain, two additional beech lineages have arrived from other refugia and occupied specific locations.

Poster presented at the International Conference “Hot Spots of Ancient and Present genetic Diversity”, 17 – 20 June 2009, Sofia Bulgaria.

Uploaded in figshare

http://figshare.com/articles/Patterns_of_cpDNA_diversity_within_a_beech_refugial_area/105909