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11.
Ecological factors affecting the recent Picea abies decline in Slovenia : the importance of bedrock type and forest naturalness
Janez Kermavnar, Lado Kutnar, Anže Martin Pintar, 2023, izvirni znanstveni članek

Povzetek: Norway spruce (Picea abies [L.] Karst.) has been at the centre of controversy for many decades. Recent evidence of its profound disturbance-induced damage and consequent stock depletions across forest landscapes in Europe has reinforced doubts regarding the sustainability and prospects of this tree species in the future. Like many other European countries, Slovenia has experienced significant Norway spruce mortality and a decrease in growing stock primarily as the result of several disturbance agents (bark beetle outbreaks, an ice storm, windthrows). We investigated a countrywide spruce growing stock decline based on data between 2010 and 2018. Particular focus was placed on identifying the main ecological drivers of this decline, namely geological conditions, climatic parameters, soil attributes, topographic factors and forest stand characteristics. The effects of potential predictors on the relative change (%) in spruce volume (m3 ha-1) during the period 2010-2018 were analysed with Generalized Additive Models. Based on a national dataset including forest compartments (n = 6355) with a spruce growing stock decline > 10%, we found mixed support for ecology-based hypotheses. While spruce decline responded to bedrock type as predicted (i.e., greater relative decline in carbonate compared to silicate compartments), higher forest naturalness (preservation of tree species composition) was not associated with a lower decline. Spruce decline was amplified by higher potential evapotranspiration and soil clay content but showed a strong negative relationship with spruce proportion in the year 2010. General trends along the gradients of other selected predictors (stoniness/rockiness and heat load index) were less pronounced. The results suggest that most of these ecological predictors interact with geology and forest naturalness in affecting Norway spruce decline. Our analysis reveals that bedrock type can play an important role due to its mitigating effects. However, forest naturalness is of secondary significance as intensified large-scale forest disturbances likely override its buffering potential.
Ključne besede: Norway Spruce, bark beetle outbreaks, ice storm, soil-geology, relationship, tree species composition, Slovenia
Objavljeno v DiRROS: 05.04.2023; Ogledov: 703; Prenosov: 188
.pdf Celotno besedilo (917,30 KB)
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12.
Are ecological niche optimum and width of forest plant species related to their functional traits?
Janez Kermavnar, Lado Kutnar, Aleksander Marinšek, Valerija Babij, 2023, izvirni znanstveni članek

Povzetek: The ecological niche is one of the central concepts in plant ecology. Understanding which biological traits influence plant niches remains limited, preventing large-scale generalizations. Using a representative pool of 94 herb-layer species frequently occurring in the Slovenian forest vegetation types and an extensive suite of 28 plant functional traits, we tested whether traits serve as predictors for the optimum and width of plant species ecological niche. Niche optimum (mean) and niche width (standard deviation) of each species were derived from community-level ecological indicator values for six environmental gradients, i.e., light, temperature, continentality, moisture, soil reaction and nutrients. We investigated relationships between niche parameters and functional traits through a random forest analysis to account for relatively high trait correlations. Our results suggest that niche optimum and width of forest plant species are related to their functional traits. The two niche parameters were best explained by similar set of traits; however, the relative importance of traits differed substantially. Traits associated with disturbances (frequency and severity), plant dispersal (seed mass, dispersal syndrome), leaf economics spectrum (specific leaf area) and life strategy (CSR scores) showed the highest overall significance in predicting niche optimum and width. Functional traits were, on average, better predictors for niche optimum (average variance explained across all six environmental factors: 20.2%) than for niche width (average variance explained: 7.7%). Intraspecific trait variability, not considered in this study, likely plays an important role in case of niche width. The analyses suggest that, while not all traits impact niche parameters to the same degree, it is crucial to consider traits representing different ecological dimensions and revealing leading patterns of trait coordination. We recommend that the relative importance of traits for species niche parameters should be tested on a larger spatial scale using broader pool of forest understory plants across Europe.
Ključne besede: ecological gradients, Ellenberg indicator values, Slovenian forest types, trait-environment relationship, understory plants
Objavljeno v DiRROS: 09.03.2023; Ogledov: 436; Prenosov: 243
.pdf Celotno besedilo (2,37 MB)
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13.
Assessing the heterogeneity and conservation status of the Natura 2000 priority forest habitat type Tilio–Acerion (9180*) based on field mapping
Janez Kermavnar, Erika Kozamernik, Lado Kutnar, 2023, izvirni znanstveni članek

Povzetek: Priority habitat types (HTs) within the Natura 2000 network are of the highest importance for conservation in Europe. However, they often occur in smaller areas and their conservation status is not well understood. One such HT is that of the Tilio–Acerion forests of slopes, screes and ravines (9180*). The Natura 2000 study site, Boč–Haloze–Donačka gora, in the Sub-Pannonian region of eastern Slovenia is characterized by a matrix of European beech forests and includes rather small, fragmented areas covered by Tilio–Acerion forests. The goal of this research was to examine the heterogeneity and conservation status of the selected HT through field mapping, which was performed in the summer of 2020. As the conservation of HT calls for a more detailed approach, we distinguished between the following four pre-defined habitat subtypes: (i) Acer pseudoplatanus-Ulmus glabra stands growing mostly in concave terrain, (ii) Fraxinus excelsior stands growing on slopes, (iii) Tilia sp. stands with thermophilous broadleaves occurring on ridges and slopes, (iv) Acer pseudoplatanus stands occurring on more acidic soils with an admixture of Castanea sativa. Field mapping information was complemented with the assessment of habitat subtype characteristics using remote sensing data. The results showed that habitat subtypes differed significantly in terms of area, tree species composition, forest stand characteristics, relief features and the various threats they experienced (e.g., fragmentation, tree mortality, ungulate browsing pressure). The differences between subtypes were also evident for LiDAR-derived environmental factors related to topography (i.e., terrain steepness and Topographic Position Index). This study provides a baseline for setting more realistic objectives for the conservation management of priority forest HTs. Due to the specificities of each individual habitat subtype, conservation activities should be targeted to the Natura 2000 habitat subtype level.
Ključne besede: forest habitat subtype, monitoring, biodiversity conservation, LiDAR, Slovenia, NATURA 2000
Objavljeno v DiRROS: 03.02.2023; Ogledov: 936; Prenosov: 240
.pdf Celotno besedilo (9,53 MB)
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14.
Funkcionalna ekologija rastlin: preverjanje izbranih konceptov na primeru rastlinskih vrst gozdnih rastiščnih tipov v Sloveniji
Janez Kermavnar, Lado Kutnar, Aleksander Marinšek, Valerija Babij, 2022, izvirni znanstveni članek

Povzetek: Na primeru flore slovenskih gozdov smo obravnavali štiri funkcionalne znake rastlin: specifična listna površina (SLP), vsebnost suhe snovi v listih (VSS), višina rastlin (VIŠ) in masa semen oz. spor (MAS). Prva dva znaka nakazujeta ekonomiko lista (način in učinkovitost izrabe virov), druga dva pa velikost rastlinskih organov. Preučili smo povezave med znaki rastlin in njihovimi fitoindikacijskimi vrednostmi za ekološke dejavnike svetloba (L), temperatura (T), kontinentalnost (K), vlažnost tal (F), reakcija tal (R) in hranila (N). Ugotovili smo statistično značilne korelacije: med SLP in R, N, L, F ter K; med VSS in R ter N; med VIŠ in N, T, R ter F; med MAS in K, R, N ter T. Vzdolž prve osi ordinacijskega prostora smo prepoznali spekter listne ekonomike, ki poteka od vrst z večjimi vrednostmi SLP na produktivnejših, a hkrati senčnih rastiščih, do rastlin z večjimi vrednostmi VSS, prilagojenih na stresne ekološke razmere (npr. nizka reakcija tal ali pomanjkanje hranil oz. vode). Največji prispevek k pojasnjevanju variabilnosti v funkcionalnih lastnostih gozdnih rastlin je imel znak VIŠ, najmanjšega pa znak MAS. Ugotovitve so primerljive z dosedanjimi raziskavami, saj oba izbrana koncepta omogočata prepoznavanje pestrosti oblik in funkcij rastlin na globalni ravni.
Ključne besede: funkcionalni znaki rastlin, specifična listna površina, vsebnost suhe snovi v listih, višina rastline, masa semena, zelnate rastline, gozdna vegetacija
Objavljeno v DiRROS: 29.12.2022; Ogledov: 1473; Prenosov: 624
.pdf Celotno besedilo (2,03 MB)
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