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Na voljo sta dva načina iskanja: enostavno in napredno. Enostavno iskanje lahko zajema niz več besed iz naslova, povzetka, ključnih besed, celotnega besedila in avtorja, zaenkrat pa ne omogoča uporabe operatorjev iskanja. Napredno iskanje omogoča omejevanje števila rezultatov iskanja z vnosom iskalnih pojmov različnih kategorij v iskalna okna in uporabo logičnih operatorjev (IN, ALI ter IN NE). V rezultatih iskanja se izpišejo krajši zapisi podatkov o gradivu, ki vsebujejo različne povezave, ki omogočajo vpogled v podroben opis gradiva (povezava iz naslova) ali sprožijo novo iskanje (po avtorjih ali ključnih besedah).

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Effects of population density and female body mass on litter size in European roe deer at a continental scale
Katarina Flajšman, Tomasz Borowik, Boštjan Pokorny, Bogumiła Jędrzejewska, 2018

Povzetek: Roe deer (Capreolus capreolus) has a wide distributional range in Europe and inhabits a broad range of habitats and environmental conditions. Thus, populations of roe deer show substantial variation in demographic parameters. We aimed to determine whether body mass and population density%which influence the reproductive potential of roe deer at a local scale%affect their reproductive potential at a biogeographical scale as well. We reviewed the literature (covering years 1948%2015) on in utero litter size in roe deer from 59 locations in 14 countries in Europe. Across study sites, mean litter size varied from 1.0 to 2.4 embryo or corpora lutea per female, and population density ranged from 4.5 to 73.5 individuals/km2. Mean body mass varied from 11.2 to 20.8 kg in subadult females and from 12.1 to 22.4 kg in adult females. Between 46° and 56° N, body mass of females did not show a significant trend of increase, whereas between 56° and 63° N, it increased with latitude (Bergmann%s rule). We used linear mixed-effects models (LMMs) to analyse the influence of body mass and population density (analysed separately) on litter size. Females with larger body mass produced larger litters, and this pattern was pronounced at both higher and lower latitudes. Higher population densities negatively affected litter size in a sample of all females. This macroecological analysis showed that factors influencing the reproductive potential of roe deer females at local scales produce similar effects at the biogeographical scale.
Ključne besede: Capreolus capreolus, In utero litter size, density-dependence, subadult and adult females, latitude, Bergmann's rule, Europe
DiRROS - Objavljeno: 20.02.2020; Ogledov: 94; Prenosov: 70
URL Celotno besedilo (0,00 KB)

Different structure of sessile oak stands affects soil moisture and soil CO2 efflux
Eva Dařenová, Matjaž Čater, 2018

Povzetek: Soil moisture, soil CO2 efflux (RS), and isotopic composition of RS (%R) were studied in three sessile oak forest stands with different management practice: a high forest (HF), a high forest converted from coppice stand (CHF), and a coppice forest (CF). Measurements were taken monthly, with each position described by light parameters. RS was driven by temperature and moisture. RS increased dramatically with moisture in relatively dry soil, while they remained on the same level when moisture exceeded 13%. Differences in mean soil moisture and RS normalized for 10 °C (R10) among the stands usually followed the pattern HF > CF > CHF. The %R was highest in CHF, but during drought the pattern was HF > CHF > CF. To test the effect of stand structure on soil moisture and R10, we analyzed relationship of these variables to light parameters calculated for the angles of 60° and 180°. Subsequently, we analyzed data from all measured positions divided according to gap fraction into six groups. The results showed that forest floor shading by the canopy decreases moisture regardless of stand type, but no significant relationship was found between the light parameters and R10. We may conclude that soil moisture is affected by canopy structure and RS by stand type.
Ključne besede: gap fraction, LAI, light parameters, Quercus petraea, soil respiration
DiRROS - Objavljeno: 20.02.2020; Ogledov: 79; Prenosov: 90
URL Celotno besedilo (0,00 KB)

Co-occurring woody species have diverse hydraulic strategies and mortality rates during an extreme drought
Daniel M. Johnson, Jean-Christophe Domec, Z. Carter Berry, Amanda M. Schwantes, Katherine A. McCulloh, David R. Woodruff, H. Wayne Polley, Remí Wortemann, Jennifer J. Swenson, D. Scott Mackay, Nate G. McDowell, 2018

Povzetek: From 2011 to 2013, Texas experienced its worst drought in recorded history. This event provided a unique natural experiment to assess species-specific responses to extreme drought and mortality of four co-occurring woody species: Quercus fusiformis, Diospyros texana, Prosopis glandulosa, and Juniperus ashei. We examined hypothesized mechanisms that could promote these species' diverse mortality patterns using postdrought measurements on surviving trees coupled to retrospective process modelling. The species exhibited a wide range of gas exchange responses, hydraulic strategies, and mortality rates. Multiple proposed indices of mortality mechanisms were inconsistent with the observed mortality patterns across species, including measures of the degree of iso/anisohydry, photosynthesis, carbohydrate depletion, and hydraulic safety margins. Large losses of spring and summer whole-tree conductance (driven by belowground losses of conductance) and shallower rooting depths were associated with species that exhibited greater mortality. Based on this retrospective analysis, we suggest that species more vulnerable to drought were more likely to have succumbed to hydraulic failure belowground.
Ključne besede: carbon, cavitation, climate change, conductance, water relations
DiRROS - Objavljeno: 20.02.2020; Ogledov: 113; Prenosov: 73
URL Celotno besedilo (0,00 KB)

Considerations and consequences of allowing DNA sequence data as types of fungal taxa
Juan Carlos Zamora, Måns Svensson, Roland Kirschner, Ibai Olariaga Ibarguren, Svengunnar Ryman, Luis Alberto Parra, József Geml, Anna Rosling, Slavomír Adamčík, Tine Grebenc, 2018

Povzetek: Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
Ključne besede: mycology, funghi, molecular genetics, DNA sequences, taxonomy
DiRROS - Objavljeno: 20.02.2020; Ogledov: 102; Prenosov: 100
URL Celotno besedilo (0,00 KB)

Comparison of an optimal regression method for climate reconstruction with the compare_methods() function from the dendroTools R package
Jernej Jevšenak, Tom Levanič, Sašo Džeroski, 2018

Povzetek: The selection of a regression technique for climate reconstruction may have an important impact on reconstructed values. In this paper, we introduce the compare_methods() function from the dendroTools R package. This function compares different regression algorithms and returns validation results for each. In addition to mean validation metrics and ranks derived from these, transfer functions should have a key role in the evaluation of different regression algorithms. These are also returned as the output of compare_methods(). Our methodology is introduced on two case studies, one using a mean vessel area (MVA) chronology and one using a standardised tree-ring width (TRW) chronology. The nonlinear machine learning methods compared in our study provided relatively small (if any) improvements in terms of explaining climatic variance. However, they do offer different treatments of extreme values, and if providing more plausible climate reconstructions, this could make them a useful tool for climate reconstruction. We propose the use of the compare_methods() function as a standard methodological check before performing climate reconstruction.
Ključne besede: regression, method comparison, artificial neural networks, model trees, bagging, linear regression, R package
DiRROS - Objavljeno: 20.02.2020; Ogledov: 92; Prenosov: 57
URL Celotno besedilo (0,00 KB)

Co-invasion of ectomycorrhizal fungi in the Brazilian Pampa biome
Marcelo Aloisio Sulzbacher, Tine Grebenc, Caroline B. Bevilacqua, Ricardo Bemfica Steffen, Gilberto Coelho, Andressa O. Silveira, Rodrigo J. S. Jacques, Zaida Ines Antoniolli, 2018

Povzetek: The introduction of ectomycorrhizal fungi along with the introduced ectomycorrhizal plants is rarely considered at the ecosystem level. In Brazil, the Pampa biome is the dominant ecosystem in the Rio Grande do Sul State, predominantly with pastoral management but intensively planted with non-native trees over the last century. Sporocarps of ectomycorrhizal and putative ectomycorrhizal fungi were collected in Pampa biome native forest vegetation and plantation forests during the period 2009%2013, with an emphasis on plantations of eucalypts and pines. Morphological analysis and molecular markers were used to identify collected sporocarps. A total of 60 different taxa were collected, mainly fitting into Australasian ectomycorrhizal fungi lineages. Among collections, two turned out to be saprotrophic species from Amanita belonging to the subsect. Vittadiniae. The ectomycorrhizal fungi reported here showed that some co-introduced lineages are frequent co-invaders in the Brazilian Pampa biome with alien ectomycorrhizal trees, especially /descolea, /hysterangium, /laccaria, /pisolithus-scleroderma lineages. No ectomycorrhizal sporocarps were found in either plantation forest or in native forest sites and no novel associations were observed between native ectomycorrhizal fungal species and introduced plants. All ectomycorrhizal fungi co-introduced in the Brazilian Pampa were recorded with plant species of Australian or North American origin. The study has raised additional questions regarding the distribution, ecology and taxonomy of fungi from the Brazilian Pampa biome.
Ključne besede: ectomycorrhiza, invasive species, fungi, forest tree plantations
DiRROS - Objavljeno: 20.02.2020; Ogledov: 112; Prenosov: 60
URL Celotno besedilo (0,00 KB)

Climatically controlled reproduction drives interannual growth variability in a temperate tree species
Andy Hacket-Pain, Davide Ascoli, Giorgio Vacchiano, Franco Biondi, Liam Cavin, Marco Conedera, Igor Drobyshev, Isabel Dorado Liñán, Andrew D. Friend, Tom Levanič, 2018

Povzetek: Climatically controlled allocation to reproduction is a key mechanism by which climate influences tree growth and may explain lagged correlations between climate and growth. We used continent-wide datasets of tree-ring chronologies and annual reproductive effort in Fagus sylvatica from 1901 to 2015 to characterise relationships between climate, reproduction and growth. Results highlight that variable allocation to reproduction is a key factor for growth in this species, and that high reproductive effort (mast years) is associated with stem growth reduction. Additionally, high reproductive effort is associated with previous summer temperature, creating lagged climate effects on growth. Consequently, understanding growth variability in forest ecosystems requires the incorporation of reproduction, which can be highly variable. Our results suggest that future response of growth dynamics to climate change in this species will be strongly influenced by the response of reproduction.
Ključne besede: dendrochronology, drought, European beech, Fagus sylvatica, forest growth, seeds
DiRROS - Objavljeno: 20.02.2020; Ogledov: 107; Prenosov: 63
URL Celotno besedilo (0,00 KB)

Characterizing Alpine pyrogeography from fire statistics
Marco Conedera, Patrik Krebs, Eva Valese, Giampaolo Cocca, Christian Schunk, Annette Menzel, Harald Vacik, Daniele Cane, Anže Japelj, Boštjan Muri, Carlo Ricotta, Stefano Oliveri, Gianni Boris Pezzatti, 2018

Povzetek: In this paper, we describe current fire characteristics in the Alpine region using a ten-year forest fire record at the third and lowest resolution of the European Classification of Territorial Units for Statistics (NUTS3). To this purpose, we performed hierarchical clustering based on the Bray-Curtis dissimilarity index on five pyrogeographic metrics. This resulted in three main geographically well-distinguished clusters (Southern, Northern, and Maritime Alps) and two small groups of outliers. From a geographic point of view, we found a clear differentiation between the high fire density on the southern slope of the Alps and the substantially lower proportion of burnt areas registered in the north. The most relevant climatic (e.g., frequency and length of drought periods), environmental (e.g., vegetation types, mean elevation and predominant orientation of valleys), and socio-economic (e.g., population density and educational level) drivers for the described clusters of fire characteristics were also identified. The proposed pyrogeographic characterisation may represent an important baseline for detecting future shifts in fire occurrence or anomalous fire seasons.
Ključne besede: fire regime metrics, fire seasonality, fire density, cluster analysis, RDA
DiRROS - Objavljeno: 20.02.2020; Ogledov: 78; Prenosov: 58
URL Celotno besedilo (0,00 KB)

Challenges for growth of beech and co-occurring conifers in a changing climate context
Edurne Martinez Del Castillo, Peter Prislan, Jožica Gričar, Vladimir Gryc, Maks Merela, Kyriaki Giagli, Martin De Luis, Hanuš Vavrčík, Katarina Čufar, 2018

Povzetek: Given recent climatic trends, it is crucial to understand the plasticity and adaptiveness of forest trees in order to evaluate their current and future responses to changing climatic conditions. We investigated inter- and intra-annual xylem growth and its relation to weather factors in European beech (Fagus sylvatica) and a co-occurring conifer, either Norway spruce (Picea abies) or Scots pine (Pinus sylvestris), at five sites with different elevations and climatic conditions, in Spain, Slovenia and the Czech Republic. The selected sites were located in central and marginal parts across the distribution range of the investigated species. The results showed that climate-growth relationships vary between different species at the same site and within the same species at different sites, indicating diverse survival strategies among the observed species but also high plastic capacity within the same species. Moreover, xylogenesis analysis revealed the capacity of trees to adapt the beginning and cessation of wood formation depending on conditions. In case of beech, shortening growth duration in dryer and warmer environments and the opposite in the case of conifers, with which the growing period was extended in such conditions. Consequently, the plasticity capacity of beech was limited due to short growth duration, while conifers (especially pine) proved to be able to compensate climatic constrictions by growing over a longer period and becoming more adapted to survival in drought-prone environments.
Ključne besede: Fagus sylvatica, Picea abies, Pinus sylvestris, xylogenesis, tree-ring growth, plasticity
DiRROS - Objavljeno: 20.02.2020; Ogledov: 121; Prenosov: 71
URL Celotno besedilo (0,00 KB)

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