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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

Povzetek: 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.
Ključne besede: dinarski jelovo-bukovi gozdovi, temperatura zraka, relativna zračna vlaga, sestojne vrzeli, zastor krošenj dreves, podnebne spremembe, Slovenija
DiRROS - Objavljeno: 20.12.2019; Ogledov: 1765; Prenosov: 589
.pdf Celotno besedilo (388,92 KB)

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Comparing observer performance in vegetation records by efficiency graphs derived from rarefaction curves
Walter Seidling, Leena Hamberg, František Máliš, Maija Salemaa, Lado Kutnar, Janusz Czerepko, Thomas Kompa, Václav Buriánek, Jean-Luc Dupouey, Anna Vodálová, Roberto Canullo, 2020

Povzetek: Species richness is a key variable in measuring diversity of ecological communities. It is crucial to get reliable estimates for the number of plant species in space (mapping) and % even more important in the context of monitoring % over time. Therefore, knowledge on error rates related to recordings of species numbers should be considered in such inventories. The performance of observers in four field tests to capture species numbers carried out in forest ecosystems in central and southern Europe were compared. Observer-related species accumulation (rarefaction) curves and derived efficiency curves were analysed, resulting in mean error rates of 29.7% and 39.4% over series of plots sized 4m2 and 100m2 respectively. As a new approach individual rarefaction and efficiency curves reveal site-specific and spatially differentiated capabilities of observers to register plant species. Since expertise and individual searching strategies are difficult to parametrise, reasons for variation in error rates remain largely unknown. However, statistical modelling with site- and scale-specific mean error rates gave an overview on important influential factors like location, scale, spatial integration, and their interactions. Our results underline the importance to incorporate specific training and inter-comparison measures in monitoring programs and critical perception of results on temporal changes of species richness.
Ključne besede: species richness, observer error, overlooking rate, misidentification rate, singleton species, ICP Forests
DiRROS - Objavljeno: 20.02.2020; Ogledov: 1057; Prenosov: 418
URL Celotno besedilo (0,00 KB)

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

Povzetek: 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.
Ključne besede: fitocenologija, gozdna vegetacija, gozdna rastišča, gozdne združbe, rastiščni tip, gozdna tla, gozdnogospodarsko načrtovanje, prenos znanja, Slovenija
DiRROS - Objavljeno: 06.04.2020; Ogledov: 1413; Prenosov: 491
.pdf Celotno besedilo (446,12 KB)

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

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
DiRROS - Objavljeno: 26.05.2020; Ogledov: 1104; Prenosov: 749
URL Celotno besedilo (0,00 KB)
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