Roman Longauer

Dynamic conservation of forest genetic resources in 33 European countries

Dynamic conservation of forest genetic resources (FGR) means maintaining the genetic diversity of trees within an evolutionary process and allowing generation turnover in the forest. We assessed the network of forests areas managed for the dynamic conservation of FGR (conservation units) across Europe (33 countries). On the basis of information available in the European Information System on FGR (EUFGIS Portal), species distribution maps, and environmental stratification of the continent, we developed ecogeographic indicators, a marginality index, and demographic indicators to assess and monitor forest conservation efforts. The pan-European network has 1967 conservation units, 2737 populations of target trees, and 86 species of target trees. We detected a poor coincidence between FGR conservation and other biodiversity conservation objectives within this network. We identified 2 complementary strategies: a species-oriented strategy in which national conservation networks are specifically designed for key target species and a site-oriented strategy in which multiple-target units include so-called secondary species conserved within a few sites. The network is highly unbalanced in terms of species representation, and 7 key target species are conserved in 60% of the conservation units. We performed specific gap analyses for 11 tree species, including assessment of ecogeographic, demographic, and genetic criteria. For each species, we identified gaps, particularly in the marginal parts of their distribution range, and found multiple redundant conservation units in other areas. The Mediterranean forests and to a lesser extent the boreal forests are underrepresented. Monitoring the conservation efficiency of each unit remains challenging; however, <2% of the conserved populations seem to be at risk of extinction. On the basis of our results, we recommend combining species-oriented and site-oriented strategies.

Fertility variation and flowering asynchrony in Pinus sylvestris: consequences for the genetic structure of progeny in seed orchards

Effects of the variation in male and female fertilities of clones, flowering phenology, and spatial distribution of clones on the genetic structure of progenies of three Scots pine seed orchards were investigated using isozyme gene markers. A pronounced variation of male and female gametic contributions was found. Most clones appear to be phenologically synchronized, but up to 15% of early or late flowering clones were found in all seed orchards. The presence of ramets, which do not belong to any seed orchard clone, does not affect allelic or genotypic diversity of the seed orchard crop. Gene-pool genetic distances based on allelic frequencies between the parental and the progeny generations are not very high, but there are certain loci exhibiting a considerable differentiation. On the other hand, variance effective population sizes indicate a substantial drift of gene frequencies between seed orchard itself and its offspring. The necessity of a cautious use of the reproductive material originating from seed orchards is emphasized.

New international long-term ecological research on air pollution effects on the Carpathian Mountain forests, Central Europe

An international cooperative project on distribution of ozone in the Carpathian Mountains, Central Europe was conducted from 1997 to 1999. Results of that project indicated that in large parts of the Carpathian Mountains, concentrations of ozone were elevated and potentially phytotoxic to forest vegetation. That study led to the establishment of new long-term studies on ecological changes in forests and other ecosystems caused by air pollution in the Retezat Mountains, Southern Carpathians, Romania and in the Tatra Mountains, Western Carpathians on the Polish-Slovak border. Both of these important mountain ranges have the status of national parks and are Man & the Biosphere Reserves. In the Retezat Mountains, the primary research objective was to evaluate how air pollution may affect forest health and biodiversity. The main research objective in the Tatra Mountains was to evaluate responses of natural and managed Norway spruce forests to air pollution and other stresses. Ambient concentrations of ozone (O(3)), sulfur dioxide (SO(2)), nitrogen oxides (NO(x)) as well as forest health and biodiversity changes were monitored on densely distributed research sites. Initial monitoring of pollutants indicated low levels of O(3), SO(2), and NO(x) in the Retezat Mountains, while elevated levels of O(3) and high deposition of atmospheric sulfur (S) and nitrogen (N) have characterized the Tatra Mountains. In the Retezat Mountains, air pollution seems to have little effect on forest health; however, there was concern that over a long time, even low levels of pollution may affect biodiversity of this important ecosystem. In contrast, severe decline of Norway spruce has been observed in the Tatra Mountains. Although bark beetle seems to be the immediate cause of that decline, long-term elevated levels of atmospheric N and S depositions and elevated O(3) could predispose trees to insect attacks and other stresses. European and US scientists studied pollution deposition, soil and plant chemistry, O(3)-sensitive plant species, forest insects, and genetic changes in the Retezat and Tatra Mountains. Results of these investigations are presented in a GIS format to allow for a better understanding of the changes and the recommendations for effective management in these two areas.

Genetic structure of a rare European conifer, Serbian spruce (Picea omorika (Panč.) Purk.)

Genetic variation in 13 populations of a Balkan endemic, Serbian spruce (Picea omorika (Panč.) Purk.), was investigated using 16 isozyme loci. Serbian spruce is characterized by low levels of genetic variation (average proportion of polymorphic loci was 20.9% and average expected heterozygosity was 0.067). In most populations, a significant surplus of heterozygotes was observed, indicating a strong selection against inbreds. In the largest populations, fixation indices were positive, probably due to within-population differentiation and the associated Wahlund effect. Despite a strong overall differentiation (FST=0.261), no geographical trends in the genetic variation could be identified. Genetic drift caused by small effective population sizes and a strong fragmentation is the most plausible explanation for such variation patterns. A Bayesian analysis of population structure revealed the existence of two clusters, which are supposed to be possible remnants of ancient differentiation within a large range of the predecessor of Serbian spruce, Picea omoricoides Weber. Ex situ conservation measures, namely establishing seed orchards from trees of mixed origin, are proposed as a necessary complement to in situ protection of natural stands.

Selection effects of air pollution on gene pools of Norway spruce, European silver fir and European beech

The effects of industrial pollution on allelic and genotypic structures of Norway spruce. European silver fir and European beech were investigated by means of isozyme analysis. In a mixed Norway spruce-silver fir forest stand in an area heavily polluted by sulphur dioxide and heavy metals in the region of Spis (eastern Slovakia), pairs of neighbouring damaged and apparently healthy trees were selected in two replicates (44 and 69 pairs in a heavily and moderately damaged stand, respectively). Pairwise sampling of trees with contrasting vitality was applied to reduce potential effects of site heterogeneity on the vitality of sampled trees. No significant differences in allelic and genotypic frequencies were found between sets of healthy and declining trees. There were differences in the single-locus heterozygosities, but these were not consistent between the replicates. However, the set of damaged trees exhibited higher levels of genetic multiplicity and diversity, possibly due to the deleterious effect of rare alleles under the conditions of air pollution. Consequently. following the decline of pollutant-sensitive trees, the remaining stand will be depleted of a part of alleles with unknown adaptive value to future selection pressures.

Adaptive genetic diversity of trees for forest conservation in a future climate: a case study on Norway spruce in Austria

Genetic resources of forest trees are considered as a key factor for the persistence of forest ecosystems because the ability of tree species to survive under changing climate depends strongly on their intraspecific variation in climate response. Therefore, utilizing available genetic variation in climate response and planting alternative provenances suitable for future climatic conditions is considered as an important adaptation measure for forestry. On the other hand, the distribution of adaptive genetic diversity of many tree species is still unknown and the predicted shift of ecological zones and species’ distribution may threaten forest genetic resources that are important for adaptation. Here, we use Norway spruce in Austria as a case study to demonstrate the genetic variation in climate response and to analyse the existing network of genetic conservation units for its effectiveness to safeguard the hotspots of adaptive and neutral genetic diversity of this species. An analysis of the climate response of 480 provenances, clustered into 9 groups of climatically similar provenances, revealed high variation among provenance groups. The most productive and promising provenance clusters for future climates originate from three regions that today depict the warmest and driest areas of the natural spruce distribution in Austria. Gap analysis of the Austrian genetic conservation units in the EUFGIS Portal suggests adequate coverage of the genetic hotspots in southern parts of Austria, but not in eastern and northern Austria. Therefore conservation measures and sustainable utilization of the valuable genetic resources in these regions need to be expanded to cover their high adaptive genetic variation and local adaptation to a warmer climate. The study shows that current conservation efforts need to be evaluated for their effectiveness to protect genetic resources that are important for the survival of trees in a future climate.

Effects of post‐glacial phylogeny and genetic diversity on the growth variability and climate sensitivity of European silver fir

Summary 1. Growth rates of European silver fi r( Abies alba Mill.) rapidly increased in the last century. At the same time, ring widths declined at the species southern distribution limits in the Mediterranean. Such diverse growth trends and responses have largely been attributed to regional climate conditions, but this was prior to considering the species’ post-glacial phylogeny. 2. A dendrochronological network composed of 1961 tree-ring width series (TRW) from 78 silver fir sites between 365 and 1400 m a.s.l. along the Carpathian Arc was compiled. Spatial differences in the species’ genetic diversity were investigated from genetic data of 69 silver fir populations in the region. Differences in growth variability and climate sensitivity were then related to post-glacial phylogeny and genetic diversity. 3. Significant differences in interannual and longer-term growth trends and climate responses across the Carpathian Arc were found to coincide with the geographical north–south separation of two post-glacial populations from effective refugia originating from the Apennine and Balkan peninsulas. Summer temperature was the main driver of growth in the western (Apennine) lineage, whereas ring widths in the Balkan population from the east were predominantly controlled by summer drought. Fir specimens that originated from the Balkan lineage exhibited higher genetic diversity and more regular growth dynamics and also appeared to be less sensitive to air pollution during the 1970s. 4. Synthesis. Although the phylogeny of forest trees has largely been neglected in most dendroecological studies, results here indicate the importance of different post-glacial histories for the growth sensitivity and adaptability to varying environmental factors. Decision-making under future climate warming scenarios (for building resilience through forest management) should therefore consider different phylogenetic origins.

Nucleotide polymorphisms related to altitude and physiological traits in contrasting provenances of Norway spruce (Picea abies)

Variation of sequences of six EST-derived markers was investigated in three Norway spruce (Picea abies [L.] Karst.) provenances originating from different altitudes growing at two contrasting trial plots in Slovakia (Veľký Lom 450 m a.s.l., Mútne-Zákamenné 1,250 m a.s.l.) within a spin-off experiment of the IUFRO 1964/68 Inventory Provenance Experiment with Norway spruce. Single nucleotide polymorphisms (SNP) were identified and differences in allele frequencies at polymorphic sites were tested against altitude or associated with physiological and growth traits (chlorophyll a fluorescence, frost resistance, height, diameter, budburst phenology).Overall, 5.1% of sites (190 in total) were polymorphic in the studied material. Although there were no differences in nucleotide diversity among provenances, the differentiation was highly significant (the overall between-population variance component assessed by the AMOVA based on both extreme populations P1 and P49 was 6.53%). Only 4 polymorphic sites differed significantly between populations after Bonferroni correction. Four sites showed significant association with phenotypic traits (breast-height diameter, stem volume, chlorophyll fluorescence). In contrast to earlier analyses of growth and physiological traits based on the same material, significant associations with polymorphic sites indicate the effect of local adaptation.

Voľba lesného reprodukčného materiálu v podmienkach klimatickej zmeny / Choice of forest reproductive material under conditions of climate change

Abstract Climate change may endanger not only yield and fulfilling the social functions of European forests, but even the survival of several tree species. The study emphasises the complexity of climatic factors and physiological mechanisms, which may potentially endanger the persistence of tree populations and which cannot be reduced to problems of drought and temperature increase. A substantial inter-population variation in traits associated with the response to climatic stress, observed in provenance experiments, is a prerequisite for the choice of proper forest reproductive material (FRM) in reforestation as a strategy of climate-change mitigation. Assisted migration, i.e., transfer of FRM from source regions, currently characterised by such climate characteristics, which are expected in the target regions in the future, requires knowledge of key stress factors (depending on the climate scenario), physiological processes associated with the adaptation to this stress, identification of genes and eventually epigenetic mechanisms, controlling adaptation processes, and finally mapping of genetic and/or epigenetic variation in key genes. For most tree species, such information is not yet available. Therefore, assisted migration under such information uncertainty needs to be complemented by in situ gene conservation measures to preserve the possibility of reversing the effects of eventual erroneous decisions on FRM transfer. Abstrakt Prebiehajúca klimatická zmena môže ohroziť nielen produkčné schopnosti európskych lesov a plnenie ich celospoločenských funkcií, ale aj samotné prežitie viacerých druhov drevín. Práca poukazuje na komplexnosť klimatických faktorov a fyziologických mechanizmov, ktoré môžu potenciálne ohrozovať prežitie drevín, a ktoré nemožno redukovať na problém sucha a zvýšenia teplôt. Značná medzipopulačná variabilita lesných drevín v znakoch súvisiacich s odozvou na klimatický stres, pozorovaná v provenienčných pokusoch, je predpokladom využitia voľby vhodného reprodukčného materiálu pri umelej obnove lesa ako stratégie adaptácie na klimatickú zmenu. Riadená migrácia, teda prenos lesného reprodukčného materiálu (LRM) zo zdrojových oblastí, ktoré v súčasnosti vykazujú klimatické charakteristiky, očakávané v cieľovej oblasti v budúcnosti, vyžaduje znalosť kľúčových stresových faktorov, závisiacich od klimatického scenára, fyziologických procesov, spojených s adaptáciou na tieto stresy, identifikáciu génov či epigenetických mechanizmov, kontrolujúcich adaptačné procesy a zmapovanie genetickej či epigenetickej variability kľúčových génov. Pri väčšine drevín tieto informácie zatiaľ nie sú k dispozícii. V podmienkach informačnej neistoty musí byť preto riadená migrácia doplnená opatreniami na zachovanie genofondu lesných drevín in situ, aby bolo možné v čo najväčšom rozsahu zvrátiť dôsledky prípadných chybných rozhodnutí pri prenose LRM.

Modelling the effects of natural and artificial regeneration on genetic structure. 1. Pure spruce stand

Modelovanie dopadov prirodzenej a umelej obnovy na genetickú štruktúru: 1. nezmiešaný smrekový porast Táto práca analyzuje priestorovú a časovú variabilitu v samčej a samičej plodnosti jedincov a ich vplyv na genetickú štruktúru potomstva v obhospodarovanom smrekovom poraste. Pre účely modelovania genetickej štruktúry a na posúdenie dopadu rôznych obnovných rubov založených na prirodzenej a umelej obnove na priestorovú genetickú štruktúru, multiplicitu, diverzitu a genotypovú štruktúru potomstva a jeho diferenciáciu od materského porastu bol použitý programový balík Eco-Gene (Degen & Gregorius & Scholz 1996). V lokalite Vyšné Hágy bola založená výskumná plocha s celkovým počtom 200 dospelých stromov. Na ploche bola zameraná pozícia každého stromu, zistená veľkosť, projekcia koruny a odhadnutá produkcia šišiek. Pomocou izoenzýmových genetických markérov z dormantných púčikov bol zistený aj genotyp každého jedinca. Modelovaním sme porovnali vhodnosť rôznych obnovných rubov z hľadiska reprodukcie genofondu resp. genetickej štruktúry materských porastov. Základným kritériom hodnotenia bola tvorba priestorovej genetickej štruktúry, sekundárnym miera diferenciácie potomstva od materskému porastu a posledným miera genetickej variability v potomstve. Po zohľadnení týchto kritérií sa v nezmiešanom smrekovom poraste ukázal ako najvhodnejší dvojfázový okrajový clonný rub a ako najmenej vhodný (možno prekvapivo) silnejší jednotlivo výberný rub. Ostatné testované ruby - maloplošný prostý jednofázový okrajový, skupinový, skupinovitý clonný a slabší jednotlivo výberný rub sa ukázali ako stredne vhodné a mali na genofond potomstva podobný vplyv. Modelling the effects of natural and artificial regeneration on genetic structure. 1. Pure spruce stand The paper focuses on the analysis and assessment of spatial and temporal variation in male and female fertility and their effect on the genetic structure of progeny in a managed stand of a pure Norway spruce. The program package Eco-Gene (Degen & Gregorius & Scholz 1996) was used to model genetic structures and to assess the influence of various regeneration systems based on natural and artificial regeneration on the formation of spatial genetic structure, allelic richness, diversity and genotype structure of progeny, and its differentiation from the maternal stand. The research plot was established in the site Vyšné Hágy with 200 adult trees. For each tree, position in the stand, crown size and its ground projection, and seed fertility were scored in the field. Besides, a multilocus genotype of each tree was determined by isozyme analyses of dormant buds. Based on the modelling, we compared various silvicultural systems, which should result in a progeny reproducing genetic structures of maternal stands. An important indicator for the evaluation of silvicultural treatments was the formation of spatial genetic structures, as a secondary criterion, we used the differentiation of progeny against mother stand. Finally, we also considered genetic variation of progenies. Considering these criteria, the most appropriate silvicultural treatment in pure spruce stands appears to be the two-phase edge shelterwood cutting. On the other hand, intensive single tree selection is maybe unexpectedly the least appropriate option. The other tested systems - single-phase edge, group, progressive group shelterwood cutting and moderate single tree selection have an equivalent, intermediate position.