Inferring fine-scale spatial structure of the brown bear (Ursus arctos) population in the Carpathians prior to infrastructure development

Landscape genetics is increasingly being used in landscape planning for biodiversity conservation by assessing habitat connectivity and identifying landscape barriers, using intraspecific genetic data and quantification of landscape heterogeneity to statistically test the link between genetic variation and landscape variability. In this study we used genetic data to understand how landscape features and environmental factors influence demographic connectedness in Europe’s largest brown bear population and to assist in mitigating planned infrastructure development in Romania. Model-based clustering inferred one large and continuous bear population across the Carpathians suggesting that suitable bear habitat has not become sufficiently fragmented to restrict movement of individuals. However, at a finer scale, large rivers, often located alongside large roads with heavy traffic, were found to restrict gene flow significantly, while eastern facing slopes promoted genetic exchange. Since the proposed highway infrastructure development threatens to fragment regions of the Carpathians where brown bears occur, we develop a decision support tool based on models that assess the landscape configuration needed for brown bear conservation using wildlife corridor parameters. Critical brown bear corridors were identified through spatial mapping and connectivity models, which may be negatively influenced by infrastructure development and which therefore require mitigation. We recommend that current and proposed infrastructure developments incorporate these findings into their design and where possible avoid construction measures that may further fragment Romania’s brown bear population or include mitigation measures where alternative routes are not feasible

Stem and Crown Characteristics of Norway Spruce [<i>Picea abies</i> (L.) Karst] Populations from Romanian Carpathians

To establish the most important Norway spruce Romanian populations, open-pollinated progeny of ten plus trees originating from 33 seed stands mapped in the Romanian Carpathians have been evaluated for stem and crown characteristics at the age of 30 years, in two field trials: one established in their natural range (Breţcu trial), while the second was located outside of their natural range, in Subcarpathian lands (Avrig trial). Significant (p < 0.05) differences were found among the seed stands in both sites for most of the characteristics, suggesting an additive genetic control with different levels of significance depending on the evaluated trait and the testing site. Location analysis also revealed a highly significant population x locality interaction for all traits. The same populations behave differently to the change of the ecological conditions. In the Avrig trial higher values were recorded than in the Breţcu trial for the tree slenderness coefficient (19%), crown slenderness coefficient (13.6%) and crown lateral area (9.4%). Although outside of their natural area, pruning height (m) increased 6.4%, however pruning height ratio (%) decreases by 1%, compared to the test established in their natural range. The populations from the Eastern Carpathians stand out by showing sustained growth and superior wood quality, while the populations from the Western Romanian Carpathians have generally smaller differences between the mean values of analysed traits in both field trials. Qualitative characteristics that influence the stability of stands to windthrow and snowbreak showed low levels of correlations to ecological gradients of the originating location of tested seed stands

Qualitative Traits of Norway Spruce [Picea abies (L.) Karst.] Depending on First-Order Branches: Evaluation in Comparative Trials

To establish the most important Norway spruce Romanian populations in order to improve the genetic value of future forests, open-pollinated progeny of ten plus trees originating from 33 Norway spruce seed sources were evaluated at the age of 30 years in two field trials established in different site conditions: outside (Avrig trial) versus natural range (Breţcu trial) of Norway spruce in Romania. Evaluations have been made concerning the most important branches characteristics, influencing wood quality: Number of branches per whorl, dominant branch insertion angle, dominant branch diameter and branch finesse. Highly significant differences (p&lt;0.001) were found among seed sources in both sites for all of the analyzed traits. The strong populations × localities interaction show the high spruce ability to react to the changing environmental conditions. Near-sites populations were placed in the first half of ranking. Smaller values were recorded in the Avrig trial than in the Breţcu trial for the number of branches per whorl (4.5%) and branches finesse (5.1%). The populations from the Eastern Carpathians stand out by showing sustained growth and superior wood quality, while the populations from the Western Romanian Carpathians generally have smaller differences between the mean values of analysed traits in both field trials. Simultaneous improvement of the spruce following quantitative and qualitative traits pending on the number of branches per whorl and branches diameter is contraindicated. The two-stage selection strategy seems to be applicable in this case

TESTING BAYESIAN ALGORITHMS TO DETECT GENETIC STRUCTURE IN TWO CLOSELY RELATED OAK TAXA

The aim of this study was to test the Bayesian algorithm implemented in the software STRUCTURE in order to detect the number of clusters, by using microsatellite data from four oak species. Several assignment models, with or without a priori grouping of individuals to species, were proposed. Better results were obtained by using the sampling location information and when only two taxa were analyzed. Particularly, pedunculate oak and sessile oak formed distinct clusters whatever the assignment model we use. By contrast, no separation between the two oaks from series Lanuginosae was observed. This can be explained, on one hand, by the small sampling size for Italian oak, or by the genetic similarities of the two pubescent oaks, namely Quercus pubescens and Q. virgiliana, on the other hand. Our findings support the hypothesis according which Italian oak is an intraspecific taxonomic unit of pubescent oak