In Neotropical regions, plantations and remnant forest populations of native trees coexist in a highly fragmented matrix and may be affected by isolation and reduction in population size, leading to ...genetic structure, inbreeding, and genetic bottlenecks that reduce the population’s genetic diversity. Tabebuia rosea variability in the Mayan Forest was studied by genotyping 30 trees from three plantations and three remnant natural populations using simple sequence repeats (SSRs) and inter-simple sequence repeats (ISSRs). Ho-SSR estimates were lower than He; the mean inbreeding coefficient was 0.07 and did not differ among populations, but was eight times higher in plantations than in remnant populations. Using ISSR data, the individuals were assigned to k = 5 and k = 4 clusters under admixture without and with geographic information used as priors in Bayesian analysis assignments. Genetic differentiation estimated with the Bayesian estimator II (0.0275 ± 0.0052) was significantly different from 0, but FST was not (0.0985 ± 0.1826), while paired FST among populations ranged from 0.05 up to 0.16. Only one remnant population displayed evidence of a genetic bottleneck. T. rosea displays a genetic structure in which the isolated remnant forest populations show moderate inbreeding levels.
Small, isolated populations are more vulnerable to natural disturbances and loss of genetic diversity. Scots pine, an abundant tree species in the boreal forest of Eurasia, has a scattered natural ...distribution across Eastern and Southern Carpathian Mountains, where only a few relict populations still exist. We estimated genetic diversity and spatial genetic structure in Scots pine on the basis of microsatellite nuclear markers (nSSR) data. We found a relatively high level of genetic diversity (He = 0.697) within populations and no evidence of recent bottlenecks. Genetic diversity was lower in peat bog populations, as compared to populations that grow on rocky slopes or acidic soils and nutrient-poor sites. Population genetic structure was weak, and genetic discontinuities among populations were detected. Spatial genetic structure (SGS) was observed in nearly all Scots pine populations. The strength of SGS, quantified by Sp statistics, varied greatly among populations, ranging from 0.0011 to 0.0207, with an average of 0.01. Our study highlights that Eastern and Southern Carpathian populations still possess high within-population diversity in spite of the recent fragmentation and reduction of the Scots pine natural distribution range. We discuss the importance of spatial patterns of genetic diversity for developing strategies of conservation and sustainable use of Scots pine genetic resources in the Carpathian region.
High-quality, suitably adapted tree seed at volume is a key component for the implementation and long-term success of forest landscape restoration (FLR). We analysed the tree seed systems in four ...Asian countries—the Philippines, Indonesia, Malaysia and India—which have committed to restore in total over 47.5 million hectares of degraded lands by 2030. We assessed the national seed systems using an established indicator framework, literature review and expert surveys and interviews. Additionally, we surveyed 61 FLR practitioners about their challenges in acquiring seed to understand how the strengths and weaknesses identified at the national level were reflected in FLR projects on the ground. Identified key constraints common to the studied countries are (i) a mismatch between the growing demand for priority native species and the limited seed supply in terms of quantity and quality, (ii) lack of effective quality control for seed of native species and (iii) lack of information about the effects of climate change on native species to guide species selection and seed sourcing and to improve the resilience of restored ecosystems. We discuss options to strengthen seed systems for native tree species both in terms of quality and volume to enable them to effectively respond to the national FLR commitments and make recommendations on promising technical solutions.
Background and Purpose:
Turkish hazel (
Corylus colurna
L.) has been overused because of its valuable wood. Recently, Turkish hazel has been found only in small isolated populations, and very small ...populations within its natural distribution area, so it has been protected under IUCN with the status "Least Concern (LC)". Therefore, the remaining Turkish hazel populations have a critical importance. Genetic conservation of this tree species plays a key role in sustainable forest development. There have been only a few studies of single populations, but an overview including all countries is still missing. The aim of this publication is to give an overview of ecological and economic importance of Turkish hazel, which is considered as a tolerant tree species to climate change, for dry and warm conditions in Central Europe.
Materials and Methods:
This review paper has been prepared based on the existing literature such as reports, theses, project documents and publications related to Turkish hazel. This paper applies a literature review of the concepts of: i) Distribution and threats of Turkish hazel, ii) Ecological and economic importance, iii) Regeneration, soil demand and shading tolerance, iv) Seed, seedling, plant production and planting, v) Competitiveness in forest communities, vi) Invasiveness and hybridization, and vii) Future stand mixtures.
Results and Conclusions:
This review paper should interest forest practitioners and scientists in all countries who work with this important and valuable tree species under climate change. At first, an inventory of all populations in each country is needed. For this purpose, research should focus on the cultivation of convenient provenances of Turkish hazel under climate change. Next, genetic differences should be determined in the laboratory using genetic markers. After the assessment of the phenotype and genotype of different provenances, it would be possible to recommend provenance for each ecological condition and assisted migration (AM). Main recommendations for each country are used for selecting and establishing gene conservation units (in-situ and ex-situ) and seed orchards that will ensure the survival of Turkish hazel, and for building the base for cultivation in the future. In addition, the results might be a basis for future provenance tests, plantations and possibilities of assisted migration attempts.
1. Local adaptation is a fundamental assumption in delineating seed zones and developing seed transfer guidelines to safeguard climatic adaptation of tree and plant species during forest regeneration ...and ecological restoration. It is also broadly assumed for forest tree species that show genetic differentiation among geographic populations, especially for those with widespread natural distributions that occur in distinct environments. 2. However, due to a scarcity of suitable data, the inference of local adaptation has rarely been validated for forest tree species through reciprocal transplant experiments (RTEs). In this study, we illustrate a novel approach to restructure tree provenance test data to conform to RTEs and use recently proposed statistical models to detect local adaptation, using white spruce Picea glauca (Moench) Voss as an example. Our research demonstrates how similar studies can be conducted to validate local adaptation in other forest species and populations, for which RTEs are lacking, but where large, high-quality provenance test data sets are available. 3. Contrary to common belief, our results show that local adaptation is absent in survival and height for white spruce populations from Ontario, Canada, although they have evolved in considerably different climatic habitats, and exhibit substantial and clinal genetic differentiation and significant genotype-by-environment interactions in these two adaptive traits. 4. Synthesis and applications. Our results show that the common assumption of local adaptation in forest tree species may not necessarily be correct within significant portions of their natural range. In forest genetic studies, population differentiation in adaptive traits has often been attributed to local adaptation without rigorous validation. Our results caution against such interpretation of experimental results. In the absence of local adaptation as shown by reciprocal transplant experiments, assisted migration may be considered as an option for enhancing forest adaptation to climate change.
A transnational network of genetic conservation units for forest trees was recently documented in Europe aiming at the conservation of evolutionary processes and the adaptive potential of natural or ...man‐made tree populations. In this study, we quantified the vulnerability of individual conservation units and the whole network to climate change using climate favourability models and the estimated velocity of climate change. Compared to the overall climate niche of the analysed target species populations at the warm and dry end of the species niche are underrepresented in the network. However, by 2100, target species in 33–65 % of conservation units, mostly located in southern Europe, will be at the limit or outside the species' current climatic niche as demonstrated by favourabilities below required model sensitivities of 95%. The highest average decrease in favourabilities throughout the network can be expected for coniferous trees although they are mainly occurring within units in mountainous landscapes for which we estimated lower velocities of change. Generally, the species‐specific estimates of favourabilities showed only low correlations to the velocity of climate change in individual units, indicating that both vulnerability measures should be considered for climate risk analysis. The variation in favourabilities among target species within the same conservation units is expected to increase with climate change and will likely require a prioritization among co‐occurring species. The present results suggest that there is a strong need to intensify monitoring efforts and to develop additional conservation measures for populations in the most vulnerable units. Also, our results call for continued transnational actions for genetic conservation of European forest trees, including the establishment of dynamic conservation populations outside the current species distribution ranges within European assisted migration schemes.
The ecological importance of scattered tree species such as elms (the European white elm, the wych elm and the field elm) is widely recognized in Europe. The European white elm, along with other elm ...species, is important as part of the traditional landscape and as a tree with multiple uses. In Germany, a total of more than 825 white elm populations numbering approximately 138,000 trees have been inventoried. Most of the largest populations are closely associated with the main rivers and concentrated mainly in the northeast of the country. However, to date there has been a lack of knowledge on the genetic structure and diversity of European white elm populations in Bavaria (southern Germany). The aim of this study was to assess genetic structure and diversity and to select putative seed stands and gene conservation units (GCU) for European white elm. Nuclear microsatellite loci (nSSR) were first selected for successful elm species discrimination. Next, in order to represent the distribution range of European white elms in Bavaria, 18 populations were selected and sampled for genetic analysis with 12 variable nSSR loci. AMOVA revealed that genetic variation is mainly distributed within populations (89%), while only 11% occurred between them (
F
ST
= 0.11). Bayesian clustering indicated the highest probability for the presence of four genetic clusters (Delta
K
= 19.954 at K4) within the dataset. However, spatial genetic structure indicates a close link to the two main river basins in Bavaria (Main River basin and the Danube River basin). Thus, our results fill existing gaps in sustainable use and conservation of rare and scattered tree species by providing insights into genetic variation and genetic structure of the species and allow us to better plan genetic conservation measures and to select GCU and seed stands in Bavaria. We, therefore, suggest that in the future all putative seed stands or gene conservation units should be assessed based on several aspects, one of them being the level of genetic diversity, before final selection and use as a source of forest reproductive material (FRM).
Safeguarding sustainability of forest ecosystems with their habitat variability and all their functions is of highest priority. Therefore, the long-term adaptability of forest ecosystems to a ...changing environment must be secured, e.g., through sustainable forest management. High adaptability is based on biological variation starting at the genetic level. Thus, the ultimate goal of the Convention on Biological Diversity (CBD) to halt the ongoing erosion of biological variation is of utmost importance for forest ecosystem functioning and sustainability. Monitoring of biological diversity over time is needed to detect changes that threaten these biological resources. Genetic variation, as an integral part of biological diversity, needs special attention, and its monitoring can ensure its effective conservation. We compare forest genetic monitoring to other biodiversity monitoring concepts. Forest genetic monitoring (FGM) enables early detection of potentially harmful changes of forest adaptability before these appear at higher biodiversity levels (e.g., species or ecosystem diversity) and can improve the sustainability of applied forest management practices and direct further research. Theoretical genetic monitoring concepts developed up to now need to be evaluated before being implemented on a national and international scale. This article provides an overview of FGM concepts and definitions, discusses their advantages and disadvantages, and provides a flow chart of the steps needed for the optimization and implementation of FGM. FGM is an important module of biodiversity monitoring, and we define an effective FGM scheme as consisting of an assessment of a forest population’s capacity to survive, reproduce, and persist under rapid environmental changes on a long-term scale.
Genetic conservation is key to maintaining forests for the future; however, these face several threats. Mexico is an example of the degradation of forest genetic resources during the past three ...decades due to its deforestation rates. This country is considered a center of pine diversity but its genetic conservation efforts are not enough. To define genetic conservation units (GCUs) and propose measures for the conservation and sustainable use of 18 Mexican pine species, we analyzed the distribution of the species at the national level and in germplasm transfer zones, and evaluated the species with a set of minimum requirements for conservation and indicators from the EUFORGEN program. We determined that 13 to 15 genetic zones harbored the target species, in which Pinus teocote, Pinus cembroides, Pinus devoniana, Pinus maximinoi, Pinus douglasiana, and Pinus leiophylla were the most widely distributed. We defined 173 areas for establishing GCUs for the total of the species studied; 50% of them were selected from areas with genetic information, 5% were selected from seed stands, and 45% from natural forests. We detected that most of the forest reproductive material used is collected from seed stands, and the use of seeds from breeding trials is scarce.
Eucalyptus urophylla is important for the establishment of commercial forest plantations in Mexico. Genetic improvement programs are currently being implemented to increase timber productivity. The ...objectives of this study were to evaluate the adaptability and growth stability of 26 clonal lines of E. urophylla in Acrisol and Fluvisol soils and to identify the most suitable genotypes for each soil type. Tree survival, diameter at breast height, and total height were measured annually for six years. These variables were used to estimate individual volume, volume per hectare, and mean annual (MAIv) and current annual (CAIv) volume increment. Survival ranged from 14 to 100% in the Acrisol soil and from 0 to 89% in the Fluvisol soil. Volume per hectare ranged from 65.3 to 488.7 m3, MAIv from 11.1 to 83.1 m3 ha−1 year−1, and CAIv from 2.4 to 134.7 m3 ha−1 year−1. Individual heritability (Hi2) was moderate (0.29–0.49) while the mean heritability of the cloned lines was high (0.73–0.90), indicating that growth is subject to high genetic control. Diameter, height, and volume presented no genotype × environment interaction effects, demonstrating stability in the growth of the clonal lines in both soil types.
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