Wood-pastures are important for their open-ground biodiversity and for the old trees they contain. However, younger trees to replace the current generation of old trees are often scarce, a potential ...threat to the future of the habitat mosaic and of species dependent on the trees. A simple model was used to illustrate how many younger trees might be expected under different assumptions of desired final density of old trees and rates of loss as trees age for an oak-dominated wood-pasture. From these the overall canopy cover of the landscape was estimated under an active pollarding regime and where the trees grow to full crown size. Canopy cover was often five times as great under full crown as under a pollarding regime; much of the canopy cover was in the younger (often missing) cohorts. The openness of current wood-pastures is in part a consequence of the absence of a sustainable tree population structure. Some protected sites may be too small to allow space for the missing generation of trees and at the same time retain current levels of openness. Analogies between current wood-pasture structures and ‘natural wood-pastures’ of the pre-Neolithic era must take account of the missing generations of trees.
Pašniki z drevesi so pomembni za biodiverziteto zaradi njihove odprtosti in zaradi prisotnih starih dreves. Vendar so mlada drevesa, ki naj bi nadomestila trenutno generacijo starih dreves redka, kar predstavlja potencialno grožnjo mozaičnemu habitatu in vrstam, ki so odvisne od prisotnosti dreves. Uporabili smo preprost model, ki predstavlja koliko mladih dreves lahko pričakujemo v različnih predvidevanih gostotah starih dreves in različnih stopnjah odmiranja starih dreves zaradi starosti na pašniku, kjer dominirajo hrasti. Iz tega smo ocenili skupno pokrovnost krošenj v krajini, če se drevesa aktivno obrezuje ali le-ta zrastejo do polne velikosti krošnje. Pokrovnost krošenj je pogosto do petkrat večja, če drevesa zrastejo do polne velikosti, kot če jih obrezujemo. Večina pokrovnosti krošenj je zaradi mlajših dreves (ki pa pogosto manjkajo). Trenutna odprtost pašno-drevesnih podsistemov je delno posledica odsotnosti trajnostne strukture drevesne populacije. Določene zaščitene površine so verjetno premajhne, da bi se lahko manjkajoče generacije dreves obnovile in da bi se obenem ohranila trenutna stopnja odprtosti pašnika. Pri analogiji med sedanjimi pašno-drevesni podsistemi in naravnimi pašniki z drevesi iz obdobja pred Neolitikom moramo upoštevati manjkajoče generacije dreves
In Europe, the management of semi-natural grasslands is changing steadily in extent and intensity. These changes represent a serious threat to one of the most species-rich habitats in Europe; ...therefore, the related shifts in species composition should be assessed by means of sound scientific.
We describe a new methodology aimed at: (i) quantifying the temporal changes in vascular plant species composition of semi-natural grasslands; (ii) identifying the environmental and management variables that drive patterns of change. Our approach consists of a diachronic analysis based on historical phytosociological data associated with detailed vegetation maps. To describe and test our methodology, in 2013 we re-visited 24 historical plots of Bromus erectus grasslands that were first sampled in 1982. To designate the new sampling sites, we combined the topographic and typological information available for the historical plots with the spatial information of the associated map. The degree of change in species composition was calculated through ordination techniques; multivariate distances were used in a regression analysis to identify the environmental variables responsible for patterns of compositional change. Our worked example demonstrated that species composition has changed significantly in the last 30 years, with patterns that have been substantially influenced by topography and landscape structure.
Gospodarjenje s pol naravnimi travišči se v Evropi spreminja po obsegu in po intenzivnosti. Spremembe predstavljajo resno grožnjo enim vrstno najbolj bogatih habitatov v Evropi, zato je potrebno ocenjevati spremembe v vrstni sestavi z znanstveno metodo. Opisujemo novo metodologijo, ki stremi h (i) kvantifikaciji časovnih sprememb v vrstni sestavi pol naravnih travišč ter (ii) opredelitvi dejavnikov okolja in gospodarjenja, ki vodijo v spremembe. Naš pristop temelji na diakronični analizi historičnih fitocenoloških podatkov v povezavi z natančnimi vegetacijskimi kartami. Za opis in preverjanje metodologije smo leta 2013 ponovno obiskali 24 starejših ploskev travišč z vrsto Bromus erectus, mi smo jih prvič vzorčili leta 1982. Za izbiro novih vzorčnih mest smo kombinirali topografske in tipološke informacije, ki so na voljo za starejše ploskve, s prostorskimi informacijami na povezani karti. Stopnjo sprememb vrstne sestave smo izračunali z ordinacijskimi metodami; uporabili smo multivariatne razdalje v regresijski analizi za opredelitev okoljskih dejavnikov odgovornih za vzorec sprememb vrstne sestave. Z našim primerom smo pokazali, da se je vrstna sestava v zadnjih 30 letih značilno spremenila, na vzorec sprememb pa sta bistveno vplivala topografija in krajinska sestava.
Provider: - Institution: - Data provided by Europeana Collections- Gospa Ana Nuša Kerševan in ljubljanski župan Zoran Janković sta ob prisotnosti otrok in zaposlenih posadila drevo v parku Osnovne ...šole Jožeta Moškriča v Novih Jaršah. - All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Gospa Ana Nuša Kerševan in podžupan Aleš Čerin sta ob prisotnosti otrok in zaposlenih posadila drevo v parku Osnovne šole Jožeta ...Moškriča v Novih Jaršah. - All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Gospa Ana Nuša Kerševan in ljubljanski župan Zoran Janković sta ob prisotnosti otrok in zaposlenih posadila drevo v parku Osnovne ...šole Jožeta Moškriča v Novih Jaršah. - All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Razglednica je bila poslana, datum na poštnem žigu je 16. 10. 1934. Na razglednici je pogled na cerkev svetega Mavra v Izoli, levo ...je neometan kamnit zvonik.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Razglednica ni bila poslana. Na razglednici je manjši trg med hišami, Piazza alle porte. Sredi trga je gruča ljudi.- All metadata ...published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain ...Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Razglednica je bila poslana, ročno napisan datum je 6. 6. 1909, datum na poštnem žigu se ne razloči. Na razglednici so stavbe v ...Izoli, kjer je danes krožišče v centru mesta. Levo je TRATTORIA ALL’ISTRIA. V ozadju so Baredi. Na cesti so gruče odraslih in otrok . Desno zgoraj je napis ALLE PORTE – ISOLA. Napis na zadnji strani: Cartolina postale.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
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