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Query: "author" (Janez Kermavnar) .

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1.
Tveganja, koristi in upravljanje s tujerodnimi drevesnimi vrstami v alpskem prostoru : rezultati spletne ankete
Aleksander Marinšek, Simon Zidar, Janez Kermavnar, Lado Kutnar, Ajša Alagić, Anica Simčič, 2022

Abstract: Prispevek predstavlja mnenja in poznavanje tujerodnih drevesnih vrst (TDV) deležnikov, ki pri svojem delu prihajajo v stik s TDV v gozdnih, urbanih in periurbanih območjih v Sloveniji. Mnenja smo pridobili s spletno anketo v letu 2020, ki je bila v okviru projekta ALPTREES del raziskave v vsaki od petih partnerskih držav (Slovenija, Avstrija, Nemčija, Italija in Francija) alpskega prostora. Analizirali smo odgovore slovenskih deležnikov in tako pridobili informacije o poznavanju, dojemanju in odnosu deležnikov do TDV. S spletnim anketiranjem smo dobili odgovore na vprašanja 120 posameznikov. Z analizo odgovorov smo ugotovili, da večina anketirancev prepoznava TDV in invazivne tujerodne drevesne vrste (ITDV) v Sloveniji. Na splošno anketiranci menijo, da TDV prinašajo tveganje v alpski prostor. Anketiranci so kot najbolj razširjene TDV ocenili robinijo (Robinia pseudoacacia), veliki pajesen (Ailanthus altissima), pavlovnijo (Paulownia tomentosa), navadno ameriško duglazijo (Pseudotsuga menziesii), rdeči hrast (Quercus rubra) in zeleni bor (Pinus strobus). Med najbolj invazivne TDV uvrščajo robinijo, veliki pajesen, pavlovnijo, octovec (Rhus typhina) in ameriški javor oz. negundovec (Acer negundo). Slaba polovica anketirancev je izrazila srednje veliko zaskrbljenost glede vpliva ITDV, kar četrtina vprašanih pa je zaradi TDV zelo zaskrbljena.
Keywords: tujerodne drevesne vrste, invazivne tujerodne drevesne vrste, alpski prostor, upravljanje, tveganje
DiRROS - Published: 08.03.2022; Views: 221; Downloads: 87
.pdf Fulltext (431,99 KB)

2.
Invazivna tujerodna rastlinska vrsta kudzu (Pueraria montana var. lobata) je potencialna grožnja za slovenske gozdove
Jana Kus Veenvliet, Aleksander Marinšek, Janez Kermavnar, Lado Kutnar, Maarten De Groot, 2019

Abstract: Kudzu (Pueraria montana var. lobata) je invazivna tujerodna rastlinska vrsta, za katero v Sloveniji do pred nedavnim ni bilo podatkov o pojavljanju v naravi. Poleti 2018 sta bili v informacijskem sistemu Invazivke (www.invazivke.si) potrjeni prvi najdbi kudzuja pri nas v naravnem okolju. V tej podatkovni bazi se kot podpora za sistem zgodnjega obveščanja in hitrega odzivanja (ZOHO), ki se razvija v sklopu projekta LIFE ARTEMIS, zbirajo podatki o invazivnih tujerodnih vrstah pri nas. Obe nahajališči kudzuja sta v submediteranskem fitogeografskem območju Slovenije, v bližini Strunjana in v Dekanih. Namen članka je predstaviti osnovne značilnosti invazivne rastlinske vrste, ki pri nas ni dobro znana. V prispevku opozarjamo tudi na potencialne negativne vplive, ki bi jih kudzu lahko povzročil z nenadzorovanim širjenjem, predvsem v gozdnem prostoru. Na ravni EU je kudzu zaradi potencialnih škodljivih vplivov na okolje uvrščen med tiste invazivne tujerodne vrste, za katere morajo države članice sprejeti takojšnje stroge ukrepe za odstranitev oziroma preprečitev širjenja. Zgodnje obveščanje in hitro odzivanje v začetnih fazah širjenja sta ključni dejavnosti, ki bistveno pripomoreta k učinkovitemu zmanjševanju negativnih vplivov invazivnih tujerodnih vrst.
Keywords: kudzu, Pueraria montana var. lobata, invazivne tujerodne vrste, Invazivke.si, gozdovi, Slovenija
DiRROS - Published: 20.03.2019; Views: 2521; Downloads: 699
.pdf Fulltext (355,72 KB)

3.
Effects of disturbance on understory vegetation across Slovenian forest ecosystems
Lado Kutnar, Thomas Andrew Nagel, Janez Kermavnar, 2019

Abstract: The herbaceous understory represents a key component of forest biodiversity across temperate forests of Europe. Here, we quantified changes in the diversity and composition of the forest understory layer in representative Slovenian forest ecosystems between 2004/05 and 2014/15. In total, 60 plots were placed across 10 different managed forest types, ranging from lowland deciduous and mid-altitude mesic mixed forests to mountain conifer forests. This network is part of an international network of sites launched within the ICP Forests Programme aimed to assess the condition of forests in Europe. To examine how disturbance influenced understory dynamics, we estimated the disturbance impacts considering both natural and/or anthropogenic disturbances that cause significant damage to trees and to ground-surface layers, including ground-vegetation layers and upper-soil layers. Species richness across 10 sites (gamma diversity) significantly decreased from 272 to 243 species during the study period, while mean species richness per site did not significantly change. The mean value of site level Shannon diversity indices and evenness significantly increased. The cover of most common plant species increased during the monitoring period. The mean value of disturbance estimates per site increased from 0.8% in 2004/05 (ranging from 0% to 2.5%) to 16.3% in 2014/15 (ranging from 5.0% to 38.8%), which corresponded to a reduction in total vegetation cover, including tree-layer cover. More disturbed sites showed larger temporal changes in species composition compared to less disturbed sites, suggesting that forest disturbances caused understory compositional shifts during the study period. Rather than observing an increase in plant diversity due to disturbance, our results suggest a short-term decrease in species number, likely driven by replacement of more specialized species with common species.
Keywords: vegetation dynamics, vascular-plant diversity, understory layer, disturbance, monitoring, temperate forests
DiRROS - Published: 27.11.2019; Views: 1676; Downloads: 1004

4.
Evaluating short-term impacts of forest management and microsite conditions on understory vegetation in temperate fir-beech forests : floristic, ecological, and trait-based perspective
Janez Kermavnar, Aleksander Marinšek, Klemen Eler, Lado Kutnar, 2019

Abstract: Forest understory vegetation is largely influenced by disturbances and given local abiotic conditions. Our research focuses on the early response of understory vegetation to various forest management intensities in Dinaric fir-beech forests in Slovenia: (i) control, (ii) 50% cut of stand growing stock, and (iii) 100% cut of stand growing stock. Apart from identifying overstory removal effects, we were interested in fine-scale variation of understory vegetation and environmental determinants of its species composition. Vegetation was sampled within 27 karst sinkholes, which represent a dominant landform in studied forests. Within each sinkhole, five sampling plots, varying in slope aspect (centre, north, east, south, west), were established (135 in total), where pre-treatment (in 2012) and post-treatment (in 2014) floristic surveys were conducted. The sampled understory species were characterized in terms of Ellenberg's indicator values (EIVs) and plant functional traits (plant height, seed mass, specific leaf area, leaf dry matter content). Diversity metrics (species richness, total cover, Shannon index) increased in plots where the silvicultural measures were applied. Tree species richness also increased in 100% cutting. A redundancy analysis revealed that species composition was related to environmental variables, which are directly influenced by management interventions (overstory canopy cover, microclimate maximum daily temperature, soil properties thickness of organic soil layer) as well as by topographic factors (slope inclination and surface rockiness). EIVs for light were significantly affected by treatment intensity, whereas soil-related EIVs (moisture, reaction, nutrients) depended more on the within-sinkhole position. Canopy gaps, compared with uncut control plots, hosted a higher number of colonizing species with a higher plant height and smaller seeds, while leaf traits did not show a clear response. We found a negative correlation between pre-treatment species (functional) richness and post-treatment shifts in floristic (functional) composition. Plots with higher richness exhibited smaller changes compared with species-poor communities. Incorporating different perspectives, the results of this study offer valuable insights into patterns of understory vegetation response to forest management in fir-beech forests.
Keywords: canopy gap, microsite environment, Ellenberg indicator values, plant functional traits, compositional resistance, karst topography, fir-beech forest
DiRROS - Published: 06.12.2019; Views: 1861; Downloads: 1004
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5.
Mikroklimatske razmere v sestojih in vrzelih dinarskih jelovobukovih gozdov Slovenije z vidika podnebnih sprememb
Lado Kutnar, Andrej Kobler, Klemen Eler, Aleksander Marinšek, Mitja Ferlan, Janez Kermavnar, 2019

Abstract: Dinarski jelovo-bukovi gozdovi so eden glavnih gozdnih vegetacijskih tipov v Sloveniji, v katerih so se v zadnjem obdobju zaradi naravnih ujm spremenile ekološke razmere. Namen raziskave je bila analiza izbranih spremenljivk mikroklime (temperatura zraka, relativna zračna vlaga) v strnjenih sestojih, v presvetljenih sestojih in v sestojnih vrzelih na treh raziskovalnih območjih (Trnovski gozd, Snežnik, Kočevski rog). Za strnjene sestoje je bila značilna visoka stopnja zastiranja tal s krošnjami dreves ( ~ 95 %). Sestojne vrzeli so nastale s posekom vseh dreves na krožni površini 0,4 ha, v presvetljenih sestojih pa je bila posekana približno polovica lesne zaloge gozdnega sestoja. Ukrepi so bili izvedeni leta 2012, meritve meteoroloških spremenljivk pa smo opravili prvo (2013) in drugo (2014) leto po sečnji. Primerjali smo, kako se mikroklimatske razmere v sestojih in vrzelih spreminjajo v vegetacijski sezoni (maj-oktober) in kakšne so razlike med dvema meteorološko razmeroma različnima poletjema v letih 2013 (več vročinskih valov, poletna suša) in 2014 (nestanovitno vreme z relativno veliko količino padavin). Izmerjene najvišje dnevne temperature zraka (Tmax) so bile izrazito višje v vrzelih kot v sestoju, v povprečju za 3,6 °C; najnižja relativna zračna vlaga (RVmin) pa je bila nižja, v povprečju za 15,0 odstotnih točk. Razlike v obeh spremenljivkah med sestoji in vrzelmi so bile največje v poletnih mesecih (junij-avgust) leta 2013 (Tmax: 4,9 °C; RVmin: -19,7 odstotnih točk), ki je bilo razmeroma vroče in sušno. Na podlagi meritev meteoroloških spremenljivk in zastora drevesnih krošenj (podatki LiDARskega snemanja) v presvetljenih sestojih smo ugotovili statistično značilno negativno linearno povezavo med zastorom drevesnih krošenj in Tmax ter pozitivno povezavo med zastorom krošenj in vrednostmi RVmin. Rezultate analiz smo prikazali v luči potencialnih vplivov podnebnih sprememb, katerim so dinarski jelovo-bukovi gozdovi zaradi kombinacije neugodnih dejavnikov npr. zmanjšana mehanska in biološka stabilnost sestojev zaradi velikopovršinskih motenj, poletne suše, vodoprepusten kraški teren ter pogosto plitva tla z majhno sposobnostjo zadrževanja vode - še posebej izpostavljeni.
Keywords: dinarski jelovo-bukovi gozdovi, temperatura zraka, relativna zračna vlaga, sestojne vrzeli, zastor krošenj dreves, podnebne spremembe, Slovenija
DiRROS - Published: 20.12.2019; Views: 1821; Downloads: 602
.pdf Fulltext (388,92 KB)

6.
7.
Delavnice s področja fitocenologije in pedologije za pripravo strokovnih izhodišč za izdelavo gozdnogospodarskih načrtov območij
Janez Kermavnar, Aleksander Marinšek, Lado Kutnar, Valerija Babij, 2020

Abstract: V letu 2019 smo v okviru Javne gozdarske službe v skupni organizaciji Zavoda za gozdove Slovenije in Gozdarskega inštituta Slovenije za gozdarje načrtovalce organizirali niz fitocenološko-pedoloških delavnic. Izvedli smo eno celodnevno teoretično delavnico v obliki predavanj in štiri terenske: za panonsko, primorsko, dinarsko in alpsko geografsko območje. Namen delavnic je priprava podlag strokovnih izhodišč na področju gozdnih rastišč, združb in gozdnih tal za izdelavo območnih gozdnogospodarskih načrtov za obdobje 2021%2030.
Keywords: fitocenologija, gozdna vegetacija, gozdna rastišča, gozdne združbe, rastiščni tip, gozdna tla, gozdnogospodarsko načrtovanje, prenos znanja, Slovenija
DiRROS - Published: 06.04.2020; Views: 1470; Downloads: 509
.pdf Fulltext (446,12 KB)

8.
Patterns of understory community assembly and plant trait-environment relationships in temperate SE European forests
Lado Kutnar, Janez Kermavnar, 2020

Abstract: 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.
Keywords: functional composition, functional diversity, ecological gradients, abiotic filtering, trait convergence, trait divergence, spatial scale, forest ground-layer vegetation, Slovenia
DiRROS - Published: 26.05.2020; Views: 1191; Downloads: 789
.pdf Fulltext (4,12 MB)

9.
Effects of various cutting treatments and topographic factors on microclimatic conditions in Dinaric fir-beech forests
Janez Kermavnar, Mitja Ferlan, Aleksander Marinšek, Klemen Eler, Andrej Kobler, Lado Kutnar, 2020

Abstract: Forest microclimate is strongly affected by local topography and management activities, as these directly alter overstory structure. In the present work we analysed the dependence of observed patterns of spatio-temporal microclimatic variations on topographic, canopy- and management-related factors. A forestry experiment was conducted in managed fir-beech forests in the Dinaric Mountains (Slovenia), which are characterized by rugged karstic terrain with numerous sinkholes. In 2012, cutting treatments representing a range in the intensity of overstory removal were performed: uncut controls (CON), 50% cut of stand growing stock (intermediate management intensity % IMI) and 100% cut (high management intensity % HMI) creating 0.4 ha canopy gaps. Fine-scale variation in aspect and slope and its effects on microclimate was assessed by comparing central, south-facing and north-facing within-sinkhole positions. We measured microclimatic variables (air temperature % T, relative humidity % RH) 0.5 m above the ground over three consecutive post-treatment growing seasons. Microclimatic variables showed an increase (T and vapour pressure deficit % VPD) or decrease (RH) with management intensity. Daily Tmax and VPDmax in HMI treatment were up to 5.9°C (on average 3.5°C) and up to 1.4 kPa (on average 0.6 kPa) higher than those in CON treatment, respectively, whereas daily RHmin was up to 22.7 (on average 13.0) percentage points lower. Regarding intra-seasonal patterns, microclimatic differences between treatments were largest during the summer. South-facing plots in the HMI treatment overall exhibited the most extreme conditions, i.e. the highest Tmax and lowest RHmin. Differences in microclimate between treatments were strongly modulated by canopy cover. The results also suggest that overstory removal increases topography-mediated variation in microclimate, as evidenced by significant differences in T, RH and VPD along the fine-scale topographic gradient within the created canopy gaps.
Keywords: tree cutting, air temperature, relative humidity, vapour pressure deficit, karst topography, canopy cover
DiRROS - Published: 08.10.2020; Views: 778; Downloads: 266
.pdf Fulltext (1,59 MB)

10.
Ocena stanja ohranjenosti habitatnega tipa 91E0* Obrečna vrbovja, jelševja in jesenovja v območju Natura 2000 Ličenca pri Poljčanah
Ruben Šprah, Anica Simčič, Janez Kermavnar, Aleksander Marinšek, Valerija Babij, Erika Kozamernik, Lado Kutnar, Ajša Alagić, 2021

Abstract: Stanje ohranjenosti sestojev habitatnega tipa 91E0* Obrečna vrbovja, jelševja in jesenovja (Alno-Padion, Alnion incanae, Salicion albae) je v Sloveniji precej zaskrbljujoče. V Sloveniji je bilo njegovo stanje ocenjeno kot slabo, trend pa negativen, kar pomeni dodatno možnost poslabšanja. Omenjeni gozdni habitatni tip sodi med prioritetne ali prednostne habitatne tipe, za katere je predvidena posebna skrb Evropske skupnosti. Zaradi njegove majhnosti in fragmentiranosti je pogosto spregledan in tudi neustrezno obravnavan. Z namenom, da bi izboljšali njegovo prepoznavnost in spoznali njegove značilnosti na terenu, smo mu v okviru LIFE integriranega projekta za okrepljeno upravljanje Nature 2000 v Sloveniji namenili posebno pozornost. V raziskavi smo z uporabo metode terenskega kartiranja podrobneje proučili stanje sestojev habitatnega tipa 91E0* v območju Natura 2000 Ličenca pri Poljčanah. Na tak način smo ugotovili, kakšna je površina sestojev tega habitatnega tipa in jo primerjali z obstoječimi conami habitatnega tipa 91E0*. Ugotavljali smo pojavljanje ključnih drevesnih vrst oz. drevesno sestavo sestojev, njihovo pomlajevanje ter vrste pritiskov in groženj za habitatni tip 91E0* na tem območju. Izmed različnih znanih podtipov habitatnega tipa 91E0* smo na tem območju našli predvsem podtip nižinsko črnojelševje, pa tudi fragmente podtipa vrbovja s topolom. Ponekod so se tudi v gozdu pojavljali manjši sestoji vrb in ozkolistnega jesena. Ugotovili smo, da površine sestojev habitatnega tipa 91E0* na območju Natura 2000 Ličenca pri Poljčanah dejansko zavzemajo le približno četrtino površine obstoječih con habitatnega tipa. Analiza drevesne sestave sestojev je pokazala predvsem vraščanje smreke v sestojih črnojelševja, le-ta naravno ni prisotna v tem habitatnem tipu. Ugotovili smo, da je na proučevanem območju pomlajevanje črne jelše zelo okrnjeno. Na slabšanje stanja sestojev črnojelševja še dodatno vplivajo različni pritiski in grožnje, kot so bližina kmetijskih površin, odpadki, fragmentacija sestojev črnojelševja, širjenje invazivnih tujerodnih rastlin, vodne regulacije, bližina prometnic, izsuševanje rastišč idr. Stanje ohranjenosti sestojev tega habitatnega tipa je bilo posledično v večini primerov ocenjeno kot neugodno do slabo. Z namenom, da bi se stanje obrečnih gozdov na območju Ličence pri Poljčanah izboljšalo, smo v prispevku predlagali nekaj konkretnih ohranitvenih ukrepov
Keywords: habitatni tip, črnojelševje, obrečni gozdovi, terensko kartiranje, stanje ohranjenosti, Alnus glutinosa, Natura 2000
DiRROS - Published: 14.04.2021; Views: 771; Downloads: 296
.pdf Fulltext (1,25 MB)

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