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Patterns of understory community assembly and plant trait-environment relationships in temperate SE European forests
Janez Kermavnar, Lado Kutnar, 2020, izvirni znanstveni članek

Povzetek: We analyzed variation in the functional composition and diversity of understory plant communities across different forest vegetation types in Slovenia. The study area comprises 10 representative forest sites covering broad gradients of environmental conditions (altitude, geology, light availability, soil type and reaction, nutrient availability, soil moisture), stand structural features and community attributes. The mean and variation of the trait values were quantified by community-weighted means and functional dispersion for four key plant functional traits: plant height, seed mass, specific leaf area and leaf dry matter content. At each study site, forest vegetation was surveyed at two different spatial scales (4 and 100 m2 ) in order to infer scale-dependent assembly rules. Patterns of community assembly were tested with a null model approach. We found that both trait means and diversity values responded to conspicuous gradients in environmental conditions and species composition across the studied forests. Our results mainly support the idea of abiotic filtering: more stressful environmental conditions (e.g., high altitude, low soil pH and low nutrient content) were occupied by communities of low functional diversity (trait convergence), which suggests a selective effect for species with traits adapted to such harsh conditions. However, trait convergence was also detected in some more resource-rich forest sites (e.g., low altitude, high soil productivity), most likely due to the presence of competitive understory species with high abundance domination. This could, at least to some extent, indicate the filtering effect of competitive interactions. Overall, we observed weak and inconsistent patterns regarding the impact of spatial scale, suggesting that similar assembly mechanisms are operating at both investigated spatial scales. Our findings contribute to the baseline understanding of the role of both abiotic and biotic constraints in forest community assembly, as evidenced by the non-random patterns in the functional structure of distinct temperate forest understories.
Ključne besede: functional composition, functional diversity, ecological gradients, abiotic filtering, trait convergence, trait divergence, spatial scale, forest ground-layer vegetation, Slovenia
Objavljeno v DiRROS: 26.05.2020; Ogledov: 1904; Prenosov: 1267
.pdf Celotno besedilo (4,12 MB)
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279.
Evaluation of forest edge structure and stability in peri-urban forests
David Hladnik, Andrej Kobler, Janez Pirnat, 2020, izvirni znanstveni članek

Povzetek: In the presented research, we studied the forest edge structure of urban and peri-urban forests on the outskirts of Ljubljana (Slovenia) consisting of a number of patches covering the collective surface of 1884 ha. They differ from each other according to the degree of fragmentation and by the share of the interior forest area. On the basis of LiDAR data, we conducted an analysis of the edges of the persistent forest patches and estimated them with regard to the land use they bordered on. The horizontal estimation of forest edges and the changes of forest edges, in the last decades, were estimated using digital orthophoto images of cyclic aerial surveys of Slovenia, from 1975 to 2018. The data, provided by LiDAR, were used to obtain an accurate estimate of forest edges and the metrics of their vertical canopy structure. On the basis of the canopy height model (CHM), we determined the height classes, the heights of the tallest trees, and indices of canopy height diversity (CHD) as variables subjected to a k-means cluster analysis. To determine the forest edge and trees stability, their heights and diameters at breast height (DBH) were measured and their canopy length and h/d (height/diameter) dimension ratios were estimated. In the study area of the Golovec forest patch, more than half of the forest edge segments (56%) border on residential buildings. After the construction of buildings, 54% of the newly formed forest edges developed a high and steep structure. Unfavorable h/d dimension ratio was estimated for 16% of trees, more among the coniferous than among the deciduous trees. Similar characteristics of newly formed forest edges bordering on built-up areas were determined in other sub-urban forest patches, despite the smaller share of such forest edges (19% and 10%, respectively). Tools and methods presented in the research enable the implementation of concrete silvicultural practices in a realistic time period and extend to ensure that adequate forestry measures are taken to minimize possible disturbances.
Ključne besede: forest ecosystem services, forest edge stability, forest edge structure, LiDAR, urban forests
Objavljeno v DiRROS: 26.05.2020; Ogledov: 1892; Prenosov: 1029
.pdf Celotno besedilo (5,67 MB)
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280.
Kirurško zdravljenje raka dojk
Janez Žgajnar, 2019, objavljeni strokovni prispevek na konferenci

Ključne besede: rak dojk, kirurško zdravljenje, onkološko zdravljenje
Objavljeno v DiRROS: 20.05.2020; Ogledov: 1351; Prenosov: 439
.pdf Celotno besedilo (60,84 KB)

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