Carbon and water exchanges of a spatially heterogeneous tree-shrub-grassland mosaic developed on former semi-dry calcareous grassland in the sub-Mediterranean region of Slovenia were studied. Using eddy covariance, the annual, seasonal and daily dynamics of net ecosystem exchange (NEE) and water vapor exchange were examined, together with their environmental controls during the period August 2008–December 2012. Over this period, the ecosystem appeared to be a carbon sink but the annual carbon fixation had a span of more than four-fold, from 82 to 351 g C m−2 yr−1. This variability was largely explained by different durations of drought events that occurred during the summer despite the high and relatively evenly distributed rainfall. This is related to the poor ecosystem rain use efficiency, only 0.10–0.35 g C m−2 yr −1 was taken up per mm of rain and the estimated deep water drainage ranged between 44 and 72% of the incoming rain.
COBISS.SI-ID: 8350329
Forests have high biodiversity, but are under threat worldwide. Sustainable forest management such as close-to-nature silviculture is needed. In this context forest management practices should be tested in regard to biodiversity. Therefore, we investigated the influence of gap formation and logging intensity on different functional groups in a close-to-nature managed fir-beech forest. Plots were selected in three areas in the Dinaric Mountains in Slovenia. In every area, nine plots were selected per area, of which three were established as control plots, three were treated with 50% logging and three with 100% logging. In every plot, the species of different functional groups were observed: ectomycorrhizal fungi, ferns, graminoids, forbs, hoverflies, carabid beetles and birds. For each of these groups, the species richness, species assemblage dissimilarity and indicator species were calculated for the different treatments. Ectomycorrhizal fungi and birds both responded to high logging intensity with a sharp decrease in the number of species; however, the results for ectomycorrhizal fungi were highly nested, while some additional bird species appeared. Graminoids and forbs were positively affected by logging intensity and saw increases in the number of species. Forbs had an almost completely new species assemblage compared to the forest species assemblages. Hoverflies were most favored by 50% logging, as these plots contained species from open areas and forest. Ferns and carabid beetles did not exhibit a response to different logging intensities. The number of indicator species was highly affected by the total number of species of the groups. However, which treatment they indicated was independent of the species richness but varied strongly per species group. The variability in responses shows that functional groups react differently to logging intensities, and the use of more functional groups improved the detection of changes due to logging. Fifty percent removal of the growing stock retained the diversity of most of the studied groups. The association of the group to vegetation structure, host species specificity or abiotic factors made them more responsive to the change associated with retention logging. The results are discussed in the context of forest management implications in regard to biodiversity.
COBISS.SI-ID: 4431782
The fate of peripheral forest tree populations is of particular interest in the context of climate change. These populations may concurrently be those where the most significant evolutionary changes will occur; those most facing increasing extinction risk; the source of migrants for the colonization of new areas at leading edges; or the source of genetic novelty for reinforcing standing genetic variation in various parts of the range. Deciding which strategy to implement for conserving and sustainably using the genetic resources of peripheral forest tree populations is a challenge. Here, we review the genetic and ecological processes acting on different types of peripheral populations and indicate why these processes may be of general interest for adapting forests and forest management to climate change. We particularly focus on peripheral populations at the rear edge of species distributions where environmental challenges are or will become most acute. We argue that peripheral forest tree populations are “natural laboratories” for resolving priority research questions such as how the complex interaction between demographic processes and natural selection shape local adaptation; and whether genetic adaptation will be sufficient to allow the long-term persistence of species within their current distribution. Peripheral populations are key assets for adaptive forestry which need specific measures for their preservation. The traditionally opposing views which may exist between conservation planning and sustainable forestry need to be reconciled and harmonized for managing peripheral populations. Based on existing knowledge, we suggest approaches and principles which may be used for the management and conservation of these distinctive and valuable populations, to maintain active genetic and ecological processes that have sustained them over time.
COBISS.SI-ID: 4430502
There is limited information on intra-annual plasticity of secondary tissues of tree species growing under different environmental conditions. To increase the knowledge about the plasticity of secondary growth, which allows trees to adapt to specific local climatic regimes, we examined climate–radial growth relationships of Norway spruce (Picea abies (L.) H. Karst.) from three contrasting locations in the temperate climatic zone by analyzing tree-ring widths for the period 1932–2010, and cell characteristics in xylem and phloem increments formed in the years 2009–2011. Variation in the structure of xylem and phloem increments clearly shows that plasticity in seasonal dynamics of cambial cell production and cell differentiation exists on xylem and phloem sides. Anatomical characteristics of xylem and phloem cells are predominantly site-specific characteristics. Xylem and phloem tissues formed in the first part of the growing season seemed to be more stable in structure, indicating their priority over latewood and late phloem for tree performance. Long-term climate and radial growth analyses revealed that growth was in general less dependent on precipitation than on temperature; however, growth sensitivity to local conditions differed among the sites. Only partial dependence of radial growth of spruce on climatic factors on the selected sites confirms its strategy to adapt the structure of wood and phloem increments to function optimally in local conditions.
COBISS.SI-ID: 4162726
This study addresses the species composition and biogeography of the genus Hydnum and its underlying variability at global scale. We used several molecular markers for identification Hydnum taxa resulting in at least 15 not yet described species. The geographic distance was the main driver of fungal community structure. Among tested variables geographic distance remains strongest factor driving taxa distribution. Results at the global scale also suggest the existence of disjunct populations related to local distribution factors
COBISS.SI-ID: 4361382