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Šumske čistine (eng. forest clearings, forest gaps, canopy openings) čine regeneracijske oblike uravnoteženih i pretežito zrelih šumskih sastojina. Kao neizostavan dio dinamike razvoja strukturno stabilnih šumskih kompleksa te posljedica otvaranja sastojinskog sklopa, odlikuju se strukturnom i mikroklimatskom jedinstvenošću te konstantnom promijenjivošću (White i Pickett 1985, Runkle i Yetter 1987, Busing i White 1997, Schliemann i Bockheim 2011). Unatoč brojnim istraživanjima šumskih čistina diljem svijeta, nedovoljno poznavanje ovakvih oblika staništa na našem području, uz varijabilnost sindinamičkih procesa u odnosu na klimu i zemljopisni položaj, najveći su uzroci problematike njihove kategorizacije. Dodatni izazov na području Hrvatske predstavlja i njihova uloga u gospodarenju šumama unutar Natura 2000 mreže (NN 7/2006), zbog čega široko shvaćeni pojam „šumske čistine“ u vegetacijskom smislu čini, ne samo izazov u gospodarenju šumama, nego potencijalno i praktični problem u obliku provođenja mjera zaštite. S ciljem približavanja postojeće problematike njihovog definiranja, ovim je radom, na temelju primjenjivih dosadašnjih istraživanja, uspostavljena strukturna kategorizacija šumskih čistina s obzirom na podrijetlo, tip (oblik), veličinu, prostorni smještaj i vegetacijsku pripadnost prema Nacionalnoj klasifikaciji staništa Republike Hrvatske, uz prijedlog održivih mjera zaštite. Predložena kategorizacija, vegetacijska pripadnost, jednako kao i mjere zaštite, podložne su naknadnim izmjenama i/ili dopunama te mogu poslužiti kao temeljno polazište budućih istraživanja ovakvih oblika staništa naših prostora.

U radu je istražena morfološka varijabilnost populacija običnoga bora na području sjeverozapadnoga dijela Male Kapele. Raznolikost i strukturiranost populacija utvrđena je na osnovi deset mjerenih morfoloških značajki iglica i češera, pri čemu su korištene deskriptivne i multivarijatne statističke metode. Provedenim istraživanjem utvrđena je niska varijabilnost morfoloških značajki, a razlike između stabala unutar populacija, kao i između populacija, potvrđene su za većinu istraživanih svojstava. Unutarpopulacijska varijabilnost bila je veća nego međupopulacijska, osim za značajke širina iglice, dužina češera i širina štitića. Istraživanjem je potvrđen i trend variranja populacija po ekološkom principu, kao i specifičan gradijent, odnosno promjena u morfološkoj varijabilnosti s obzirom na promjenu nadmorske visine. Populacije s nižih nadmorskih visina imale su manje češere u odnosu na populacije s viših nadmorskih visina. Osim toga, pionirski karakter običnoga bora u kojega ponekad vrlo mali broj jedinki sudjeluje u osnivanju novih populacija, rezultirao je malom varijabilnošću populacija te njihovom velikom diferencijacijom na tako malom području., The paper explores the morphological variability of the Scots pine populations in the northwestern part of Mala Kapela. The diversity and structure of the populations were established based on the ten measured morphological characteristics of the needles and cones, using descriptive and multivariate statistical methods. The conducted research established low variability of the morphological characteristics, and the differences between the trees both within and between populations were confirmed for the majority of the studied characteristics. Intrapopulation variability was greater than the interpopulation one, except for the characteristics of needle width, cone length and apophysis width. The research has also confirmed a population variation trend following the ecological principle, as well as a specific gradient, i.e. change in morphological variability related to the change in altitude. Populations from lower altitudes had smaller cones as compared to the populations from higher altitudes. In addition, the pioneering nature of the Scots pine, in which sometimes a very small number of specimens participates in the establishment of new populations, has resulted in low variability of populations and their great differentiation in such a small area.

Common or English yew (Taxus baccata L., Taxaceae) is a conifer species, native to Europe, northern Africa, Asia Minor and Caucasus. It is a dioecious, wind-pollinated and animal-dispersed tree, known for its high-quality wood and medicinal properties, albeit poisonous. The species is rare and has been legally protected at the European and national levels. In addition, its low population density and disjunct character of distribution have reinforced the need for its protection as regeneration is mostly lacking. The aim of this study was to phenotypically characterise the north-western Balkan yew populations. Phenotypic diversity was examined for seven populations, using morphometric analysis of nine phenotypic traits of needles. Descriptive and multivariate statistical analyses were conducted to evaluate the inter- and intrapopulation variability. In addition, to test correlations between geographic, climatic and phenotypic data, Mantel test was used. We identified a geographic structure across studied populations that exhibited high levels of variability on intra- and interpopulation levels. Two groups of populations have been defined and are consistent with previously described genetic divergent lineages from separate refugia. In addition, a significant correlation between phenotypic and geographic data were revealed, i.e., isolation by distance (IBD). However, the Mantel test revealed no significant correlation between morphometric and environmental data. In conclusion, our data reveal that the historical events and persistent IBD acted in combination to produce the morphological patterns observed in common yew populations in the north-western part of the Balkan Peninsula. Finally, we suggested conservation measures to be implemented on a stand level, with habitat preservation as the main goal. In addition, ex situ conservation should be considered, both in the form of collections and urban planting, as both provide additional gene pool reserves.

U članku je opisano 11 šumskih stanišnih tipova iz Nacionalne klasifikacije staništa Republike Hrvatske, koji su inače svrstani u stanišne tipove 91F0 i 91L0 Natura 2000. Prvi tip u Hrvatskoj obuhvaća povremeno poplavne i mokre šume hrasta lužnjaka u kojima prevladavaju higrofilne vrste, a tip 91L0 obuhvaća šume hrasta lužnjaka i običnoga graba na mikrouzvisinama nizinskoga područja i šume hrasta kitnjaka i običnoga graba u brežuljkastom vegetacijskom pojasu. U njima izostaju higrofiti, a velik je udio mezofilnih vrsta među kojima se u kitnjakovo-grabovim šumama ističu one ilirskoga flornoga geoelementa. Svaki je tip iz Nacionalne klasifikacije staništa kratko opisan uz navod dijagnostičkih pokazatelja važnih za njegovu identifikaciju i razgraničenje od povezanih tipova. Naveden je i odgovarajući kôd prema EUNIS-ovoj klasifikaciji i literatura u kojoj je podrobnije opisan., The article describes the 91F0 and 91L0 Natura 2000 habitat types in Croatia. It containes 11 types according to the National Habitat Classification of Croatia (NHC).The 91E0 habitat type extends to northern Croatia, in the river valleys of Sava and Drava, to approximately 100,000 ha. It consists of forests dominated by Quercus robur in admixture with Fraxinus angustifolia, Alnus glutinosa and Ulmus minor. Carpinus betulus and mesophilic species are absent. The habitat is wet, with a high level of groundwater. Floods are periodic and do not last long.According to the NHC, type 91F0 includes phytocenoses: E.2.2.1. Genisto elatae-Quercetum roboris caricetosum remotae Horvat 1938 E.2.2.2. Genisto elatae-Quercetum roboris caricetosum brizoides Horvat 1938 E.2.2.3. Genisto elatae-Quercetum roboris aceretosum tatarici Rauš 1975 E.2.2.4. Genisto elatae-Quercetum roboris carpinetosum betuli Glavač 1961Habitat type 91L0 comprises of two groups of syntaxons: pedunculate oak and hornbeam communities and sessile oak and and hornbeam communities. Pedunculate oak and hornbeam forests grow on the highest parts of the lowlands of Croatia. The ground is fresh, the groundwater level is lower than in the 91F0 type, and in floral composition there is a significant share of Central European mesophilic species. Sessile oak and hornbeam communities grow in hilly belt of continental Croatia, predominantly in brown forest soils of neutrophil character. The main tree species are Quercus petraea, Carpinus betulus, Acer campestre, Prunus avium and Fagus sylvatica. Within the shrub and herb layer the Illyrian floral element is significant, with species Lonicera caprifolium, Staphylea pinnata, Epimedium alpinum, Erythronium dens-canis, Helleborus atrorubens, Vicia oroboides and others.According to the NHC, type 91L0 includes phytocenoses:Pedunculate oak and hornbeam communities (Carpinion betuli) E.3.1.1. Carpino betuli-Quercetum roboris typicum Rauš 1975 E.3.1.2. Carpino betuli-Quercetum roboris fagetosum Rauš 1975 E.3.1.3. Carpino betuli-Quercetum roboris quercetosum cerris Rauš 1971 E.3.1.4. Carpino betuli-Quercetum roboris tilietosum tomentosae Rauš 1971Sessile oak and and hornbeam communities (Erythronio-Carpinion) E.3.1.5. Epimedio-Carpinetum betuli /Ht. 1938/ Borhidi 1963) E.3.1.6. Festuco drymeiae-Carpinetum Vukelić ex Marinček 1994) E.3.1.7. Anemone nemorosae-Carpinetum Trinajstić 1964 This article contains a description, area of distribution in Croatia, and diagnostic indicators for each habitat type. For each type related types are listed, the corresponding code according to EUNIS-classification, and literature in which is described in more detail. The article is intended for forestry experts, for identification and mapping of forest habitat types.

U članku su prikazani prvi rezultati monitoringa stanišnoga tipa 91E0* Natura 2000 u Nacionalnom parku Plitvička jezera. Taj se stanišni tip prostire u šumama crne johe (Alnus glutinosa /L./ Gaertn.) u kojima je postavljeno i snimljeno dvadeset ploha, dok pet snimaka potječe iz prijašnjih istraživanja. Istraživane sastojine imaju intenzivan sukcesijski razvoj, bogat florni sastav, veliku pokrovnost vrsta, prevlast higrofita uz slabiji udjel mezofita. Sintaksonomski pripadaju razredu Alnetea glutinosae i njegovim nižim jedinicama., The paper presents the first results of monitoring Natura 2000 habitat type 91E0*in the Plitvice Lakes National Park (Croatia). This type is represented in black alder forests (Alnus glutinosa /L./ Gaertn.) on an area of 44 ha. There, following the Braun-Blanquet method (1964), 25 plots were set up and relevés made, with 175 species of higher plant species recorded. Their environmental and sociological features suggest wetland and periodically flooded habitats with high ground water levels throughout the year, hence hygrophytes are decisive for the community structure. In addition, there is a moderate share of mesophilic species that are not present in the wetland black alder forests along the Sava and Drava rivers in the lowland part of northern Croatia.A comparison of black alder forests of the Plitvice Lakes NP with other black alder syntaxa in Croatia (Figure 2, Table 3) demonstrates that, together with other alder stands in the Dinaric region of Croatia, they belong to the group of wetland forests of the alliance Alnion glutinosae. Their differentiating species with regard to other syntaxa of the alliances Alnion glutinosae and Alnion incanae in Croatia are Fraxinus excelsior, Daphne mezereum, Viburnum lantana, Cirsium oleraceum, Crepis paludosa, Equisetum arvense, Paris quadrifolia, Thalictrum aquilegifolium, Valeriana dioica, Veratrum album, Acer pseudoplatanus, Chaerophyllum hirsutum, Lonicera xylosteum, Filipendula ulmaria, Knautia drymeia, Cruciata glabra. In addition, the researched stands in the Plitvice Lakes NP demonstrate individuality with regard to other stands of the Croatian Dinarides through the differentiating species of Phalaris arundinacea, Dactylorhiza maculata, Cirsium arvense, Primula vulgaris, Listera ovata, Carex acutiformis, C. paniculata, Succisa pratensis, Gentiana asclepiadea.Black alder forests in the Plitvice Lakes NP were created by successive processes in non-forest areas after their fall out of use (Figure 1). They grow by watercourses in karst depressions with occasionally stagnant surface water. Here the river courses are slowed down and distanced from the slopes and surrounding massifs, hence zonal forests do not have a dominant influence on the floral composition.The researched forests are classified in the class Alnetea glutinosae Br.-Bl. et Tx. 1943, order Alnetalia glutinosae Tx. 1937, and alliance Alnion glutinosae Malcuit 1929. They exhibit greatest similarity to the Central European association Carici acutiformis-Alnetum glutinosae. However, these results should not be generalized for the entire Dinaric region of Croatia. Detailed studies of black alder forests in the Dinarides are pending and their results will determine their nomenclature and syntaxonomic character.

U radu je opisano 16 šumskih stanišnih tipova iz Nacionalne klasifikacije staništa Republike Hrvatske koji su obuhvaćeni stanišnim tipom 91E0* Natura 2000. On je prioritetni europski stanišni tip, a odnosi se na močvarne, povremeno poplavne i vlažne šumske zajednice. Od drveća prevladavaju – ovisno o tipu – uskolisne vrbe, bijela i crna topola, bijela i crna joha, poljski i obični jasen. U prizemnom su sloju glavne higrofilne vrste uz veći ili manji udjel biljaka iz okolnih šuma viših položaja. U članku je europski stanišni tip 91E0* detaljnije prikazan, a svaki stanišni tip iz nacionalne klasifikacije predstavljen je kratkim opisom s arealom i dijagnostičkim pokazateljima. Također su navedeni i njegovi povezani tipovi, odgovarajući kôd prema EUNIS-ovoj klasifikaciji i literatura u kojoj je podrobnije opisan. Članak ima praktičnu važnost jer pomaže u prepoznavanju i kartiranju šumskih stanišnih tipova, a ti se zadaci upravo provode u hrvatskom šumarstvu., Habitat type 91E0in Croatiaextends to approximately 80,000 ha.It contains 16 types according to the National habitat classification of Croatia (NHC). They are based on phytosociological principles and are aligned with the level of association. They are:E.1. Riparian alluvial willow forests (Salicion albae Soó 1930), poplar (Populion albae Br.-Bl. 1931) and white alder forests (Alnion incanae Pawl. in Pawl. et al. 1928) Riparian alluvial willow and poplar forests (Salicion albae, Populion albae) E.1.1.1. – Salicetum albae-fragilis Soó (1930) 1958 E.1.1.2. – Salicetum albae Isller 1926 E.1.1.3. – Salici-Populetum nigrae (R. Tx. 1931) Meyer Drees 1936 E.1.2.1. – Populetum albae (Br.-Bl.) Tchou 1947 E.1.2.2. – Populetum nigro-albae Slavnić 1952 Alluvial white alder forests (Alnion incanae) E.1.3.1. – Equiseto hyemali-Alnetum incanae M. Moor 1958 E.1.3.2. – Lamio orvalae-Alnetum incanae Dakskobler 2010E.2. Floodplain forests of pedunculate oak, black alder and narrow-leaved ash (Alnion glutinosae Malcuit 1929, Alnion incanae) Swamp and floodplain forests of black alder narrow-leaved ash (Alnion glutinosae) E.2.1.4. – Frangulo-Alnetum glutinosae Rauš (1971) 1973 E.2.1.6. – Carici elongatae-Alnetum glutinosae W. Koch 1926 ex Tx. 1931 E.2.1.7. – Leucojo-Fraxinetum angustifoliae Glavač 1959 E.2.1.9. – Carici acutiformis-Alnetum glutinosae Scamoni 1935 Alluvial and wetland forests of black alder, elms, narrow-leaved and common ash (Alnion incanae) E.2.1.1. – Fraxino angustifoliae-Ulmetum laevis Slavnić 1952 E.2.1.2. – Carici remotae-Fraxinetum excelsioris W. Koch 1926 ex Faber 1936 E.2.1.3. – Carici brizoidis-Alnetum glutinosae Horvat 1938 E.2.1.5. – Pruno-Fraxinetum angustifoliae Glavač 1960 E.2.1.8. – Stellario nemorum-Alnetum glutinosae Lohmayer 1957 The article contains a description, area of distribution in Croatia, and diagnostic indicators for each type. For each type related types are listed, the corresponding code according to EUNIS-classification, and literature in which is described in more detail. This article has practical importance because it helps in the identification and mapping of forest habitat types, and these tasks are currently being implemented in the Croatian forestry.

The paper presents the first results of monitoring Natura 2000 habitat type 91E0*in the Plitvice Lakes National Park (Croatia). This type is represented in black alder forests (Alnus glutinosa /L./ Gaertn.) on an area of 44 ha. There, following the Braun-Blanquet method (1964), 25 plots were set up and relevés made, with 175 species of higher plant species recorded. Their environmental and sociological features suggest wetland and periodically flooded habitats with high ground water levels throughout the year, hence hygrophytes are decisive for the community structure. In addition, there is a moderate share of mesophilic species that are not present in the wetland black alder forests along the Sava and Drava rivers in the lowland part of northern Croatia. A comparison of black alder forests of the Plitvice Lakes NP with other black alder syntaxa in Croatia (Figure 2, Table 3) demonstrates that, together with other alder stands in the Dinaric region of Croatia, they belong to the group of wetland forests of the alliance Alnion glutinosae. Their differentiating species with regard to other syntaxa of the alliances Alnion glutinosae and Alnion incanae in Croatia are Fraxinus excelsior, Daphne mezereum, Viburnum lantana, Cirsium oleraceum, Crepis paludosa, Equisetum arvense, Paris quadrifolia, Thalictrum aquilegifolium, Valeriana dioica, Veratrum album, Acer pseudoplatanus, Chaerophyllum hirsutum, Lonicera xylosteum, Filipendula ulmaria, Knautia drymeia, Cruciata glabra. In addition, the researched stands in the Plitvice Lakes NP demonstrate individuality with regard to other stands of the Croatian Dinarides through the differentiating species of Phalaris arundinacea, Dactylorhiza maculata, Cirsium arvense, Primula vulgaris, Listera ovata, Carex acutiformis, C. paniculata, Succisa pratensis, Gentiana asclepiadea. Black alder forests in the Plitvice Lakes NP were created by successive processes in non-forest areas after their fall out of use (Figure 1). They grow by watercourses in karst depressions with occasionally stagnant surface water. Here the river courses are slowed down and distanced from the slopes and surrounding massifs, hence zonal forests do not have a dominant influence on the floral composition. The researched forests are classified in the class Alnetea glutinosae Br.-Bl. et Tx. 1943, order Alnetalia glutinosae Tx. 1937, and alliance Alnion glutinosae Malcuit 1929. They exhibit greatest similarity to the Central European association Carici acutiformis-Alnetum glutinosae. However, these results should not be generalized for the entire Dinaric region of Croatia. Detailed studies of black alder forests in the Dinarides are pending and their results will determine their nomenclature and syntaxonomic character.

We studied the morphological variation and its correlation to the environment in a boreal tree species, Alnus incana (L.) Moench subsp. incana, across the Croatian continental and Alpine-Dinaric biogeographical regions. A total of seven grey alder populations from environmentally divergent habitats were included in the study. We combined descriptive and multivariate statistical methods by using morphological leaf traits and environmental features to examine the diversity and structure of grey alder populations. High phenotypic variation, and two distinct morphotypes were found: small-leaf in the Alpine-Dinaric region, and large-leaf in the continental region. We identified a biogeographical structuring of populations with a high level of among-tree variation within the populations. Multivariate phenotypic and environmental analysis confirmed the existence of small- and large-leaf ecotypes. Additionally, a lack of significant among-population variation within biogeographical regions was observed. Furthermore, we found that phenotypic divergence of the studied grey alder populations can be explained as a result of a significant level of isolation both by distance and by environment., Bijela, odnosno siva joha, Alnus incana (L.) Moench subsp. incana, listopadna je, jednodomna i anemofilna drvenasta vrsta iz porodice Betulaceae. Prirodno je rasprostranjena u sjevernoj, srednjoj i mjestimično južnoj Europi, zapadnom Sibiru i Turskoj, od nizinskoga pojasa do preko 1800 m nadmorske visine u alpskom području. Bijela joha je mezofilna do higrofilna vrsta koja dobro podnosi oštru planinsku i kontinentalnu klimu, a raste na karbonatnim, ali i silikatnim, pjeskovitim, šljunčanim, slabo humusnim tlima. Najčešća je u planinskim dolinama, uz potoke i rijeke gdje na vlažnim staništima s mnogim higrofilnim vrstama tvori guste, fragmentarne sastojine, često obnovljene iz panja. To su povremeno plavljeni lokaliteti uz vodotoke ili okolne padine kroz koje se postrano procjeđuje voda prema glavnom vodotoku.Prisutnost bijele johe u Hrvatskoj vezana je za dva oštro ograničena područja: sjeveroistočno, u nizinskom dijelu Hrvatske (110 do 190 m nadmorske visine) uz tok rijeke Drave; i sjeverozapadno, u alpsko-dinarskom području uz rijeku Kupu i njene pritoke (220 do 550 m nadmorske visine).U sjeveroistočnom području rasprostiru se sastojine definirane kao Equiseto hyemali-Alnetum incanae Moor 1958 (Trinajstić 1964; Franjić et al. 1999), u kojima se u odnosu na sastojine bijele johe u gorskome području kao razlikovne vrste izdvajaju: Ulmus laevis Pall., U. minor Mill., Prunus padus L., Equisetum hyemale L. i druge. Ove sastojine danas su rjeđe nego nekada, manje se koriste, a zbog nekadašnjeg načina sječe vrlo su često panjače. Nekadašnje šumske površine koje je Trinajstić istraživao (1964) danas više nisu pod šumom. Poplavne i vlažne šume u blizini urbanih središta isušuju se, a na njihovim su staništima izgrađena naselja i komunalna infrastruktura tako da su danas šume sive johe uz tok rijeke Drave u velikoj regresiji.U alpsko-dinarskom području istraživane sastojine svrstane su u šumsku zajednicu Lamio orvalae-Alnetum incanae Dakskobler 2010, a opisane su kao geografska varijanta Helleborus dumetorum (Vukelić et al. 2012, 2017). Ona se ističe mnogim vrstama iz dinarske vegetacijske zone, poput Fraxinus excelsior L., Ulmus glabra Huds., Fagus sylvatica L., Acer pseudoplatanus L., Lamium orvala L., Lunaria rediviva L., Scopolia carniolica Jacq., Helleborus dumetorum Waldst. et Kit., Knautia drymeia Heuff. subsp. drymeia i druge. Siva joha ovdje raste u kanjonu Kupe i na obalnim terasama koje su uglavnom antropogenizirane, a nekoć su bile korištene u poljoprivrednoj proizvodnji.Glavni ciljevi rada bili su utvrditi morfološku raznolikost i strukturiranost populacija bijele johe u Hrvatskoj te istražiti na koji način ekološki i geografski čimbenici utječu na varijabilnost populacija.Materijal za morfometrijsku analizu sakupljen je iz sedam prirodnih populacija – tri iz kontinentalne i četiri iz alpsko-dinarske regije (slika 1). Svaka populacija predstavljena je s 20 stabala, a svako stablo s 20 zdravih i neoštećenih listova s kratkih fertilnih izbojaka iz vanjskog, osvijetljenog dijela krošnje. Listovi su sakupljeni početkom srpnja 2016. godine, odnosno sredinom vegetacijskog razdoblja, kada su s obzirom na dimenzije i oblik u potpunosti razvijeni. Listovi su skenirani i izmjereni pomoću programa WinFolia. Ukupno je izmjereno devet lisnih značajki (slika 2).Deskriptivnim statističkim metodama utvrđena je visoka varijabilnost listova bijele johe, kao i jasan trend divergencije između kontinentalnih i alpsko-dinarskih populacija (slika 3). Najvarijabilnijim su se pokazale značajke: površina plojke, širina lista mjerena na 90 % dužine plojke i dužina peteljke. Za razliku od toga, najmanji stupanj varijabilnosti zabilježen je za varijable koje opisuju osnovu lisne plojke. Iako je trend variranja pojedinih značajki po populacijama bio sličan, u populacijama alpsko-dinarske regije zabilježena je nešto viša unutar-populacijska raznolikost. Kontinentalne populacije su imale veće vrijednosti svih mjerenih značajki lista u odnosu na populacije iz alpsko-dinarske regije.Analizom varijance, utvrđene su statistički značajne razlike između istraživanih regija te između stabla unutar populacija, dok su se populacije unutar regija razlikovale samo za četiri istraživane značajke (tablica 1). Unutarpopulacijska varijabilnost veća je od međupopulacijske varijabilnosti, što je odlika mnogih vrsta drveća. Multivarijatne analize potvrđuju postojanje jasne razlike između kontinentalnih i alpsko-dinarskih populacija bijele johe (slika 1, slika 4, tablica 3), što upućuje na mogućnost da istraživane populacije predstavljaju dva različita ekotipa.Morfološka udaljenost između populacija bila je korelirana s geografskom i ekološkom udaljenošću, što potvrđuje uzorak „isolation by distance“ i „isolation by environmental distance“. Drugim riječima, utvrđeno je da geografska udaljenost i ekološka divergencija imaju važan utjecaj na oblikovanje morfološke strukture populacija te da je ona posljedica njihove moguće lokalne prilagodbe na okolišne uvjete i njihove geografske udaljenosti (tablica 2).Dobivene spoznaje o varijabilnosti populacija mogu doprinijeti razvoju učinkovitijih planova očuvanja i gospodarenja sivom johom u Hrvatskoj. Kako bi se potvrdili dobiveni zaključci o varijabilnosti populacija sive johe dobiveni morfometrijskim metodama, istraživanja je svakako potrebno proširiti i na molekularno-biološke metode.

Background and Purpose: The paper presents the forest vegetation of periodically flooded and wet forests of hardwood tree species along the Mirna River (Istria, Croatia). The main objective was to study the older and less influential stands, and to compare them among themselves and with related syntaxa of the Mediterranean and continental area. Materials and Methods: The research was conducted on the basis of 33 new phytocoenological relevés and 12 from previous studies, according to the principles of the standard Central European Phytocoenological School. Results and Conclusions: Based on 45 phytocoenological relevés two main vegetation types were found. In the lowest and periodically flooded habitats grow forests dominated by Fraxinus angustifolia and numerous hygrophilous species. In somewhat higher and drier localities, but with a high level of ground waters, grow mixed forests of Quercus robur, Fraxinus angustifolia, Ulmus minor and Carpinus betulus, with a greater presence of mesophilous species. The paper analyzes their mutual relationship, phytocoenological affiliation, as well as their position with regard to the related syntaxa of the Mediterranean and continental area. The results suggest isolation and a transitional character of the studied forests, which is a consequence of the biogeographical position in the north Mediterranean, of the ecological conditions, and to a lesser extent of anthropogenic influence.

Bijela, odnosno siva joha, Alnus incana (L.) Moench subsp. incana, listopadna je, jednodomna i anemofilna drvenasta vrsta iz porodice Betulaceae. Prirodno je rasprostranjena u sjevernoj, srednjoj i mjestimično južnoj Europi, zapadnom Sibiru i Turskoj, od nizinskoga pojasa do preko 1800 m nadmorske visine u alpskom području. Bijela joha je mezofilna do higrofilna vrsta koja dobro podnosi oštru planinsku i kontinentalnu klimu, a raste na karbonatnim, ali i silikatnim, pjeskovitim, šljunčanim, slabo humusnim tlima. Najčešća je u planinskim dolinama, uz potoke i rijeke gdje na vlažnim staništima s mnogim higrofilnim vrstama tvori guste, fragmentarne sastojine, često obnovljene iz panja. To su povremeno plavljeni lokaliteti uz vodotoke ili okolne padine kroz koje se postrano procjeđuje voda prema glavnom vodotoku. Prisutnost bijele johe u Hrvatskoj vezana je za dva oštro ograničena područja: sjeveroistočno, u nizinskom dijelu Hrvatske (110 do 190 m nadmorske visine) uz tok rijeke Drave; i sjeverozapadno, u alpsko-dinarskom području uz rijeku Kupu i njene pritoke (220 do 550 m nadmorske visine). U sjeveroistočnom području rasprostiru se sastojine definirane kao Equiseto hyemali-Alnetum incanae Moor 1958 (Trinajstić 1964; Franjić et al. 1999), u kojima se u odnosu na sastojine bijele johe u gorskome području kao razlikovne vrste izdvajaju: Ulmus laevis Pall., U. minor Mill., Prunus padus L., Equisetum hyemale L. i druge. Ove sastojine danas su rjeđe nego nekada, manje se koriste, a zbog nekadašnjeg načina sječe vrlo su često panjače. Nekadašnje šumske površine koje je Trinajstić istraživao (1964) danas više nisu pod šumom. Poplavne i vlažne šume u blizini urbanih središta isušuju se, a na njihovim su staništima izgrađena naselja i komunalna infrastruktura tako da su danas šume sive johe uz tok rijeke Drave u velikoj regresiji. U alpsko-dinarskom području istraživane sastojine svrstane su u šumsku zajednicu Lamio orvalae-Alnetum incanae Dakskobler 2010, a opisane su kao geografska varijanta Helleborus dumetorum (Vukelić et al. 2012, 2017). Ona se ističe mnogim vrstama iz dinarske vegetacijske zone, poput Fraxinus excelsior L., Ulmus glabra Huds., Fagus sylvatica L., Acer pseudoplatanus L., Lamium orvala L., Lunaria rediviva L., Scopolia carniolica Jacq., Helleborus dumetorum Waldst. et Kit., Knautia drymeia Heuff. subsp. drymeia i druge. Siva joha ovdje raste u kanjonu Kupe i na obalnim terasama koje su uglavnom antropogenizirane, a nekoć su bile korištene u poljoprivrednoj proizvodnji. Glavni ciljevi rada bili su utvrditi morfološku raznolikost i strukturiranost populacija bijele johe u Hrvatskoj te istražiti na koji način ekološki i geografski čimbenici utječu na varijabilnost populacija. Materijal za morfometrijsku analizu sakupljen je iz sedam prirodnih populacija – tri iz kontinentalne i četiri iz alpsko-dinarske regije (slika 1). Svaka populacija predstavljena je s 20 stabala, a svako stablo s 20 zdravih i neoštećenih listova s kratkih fertilnih izbojaka iz vanjskog, osvijetljenog dijela krošnje. Listovi su sakupljeni početkom srpnja 2016. godine, odnosno sredinom vegetacijskog razdoblja, kada su s obzirom na dimenzije i oblik u potpunosti razvijeni. Listovi su skenirani i izmjereni pomoću programa WinFolia. Ukupno je izmjereno devet lisnih značajki (slika 2). Deskriptivnim statističkim metodama utvrđena je visoka varijabilnost listova bijele johe, kao i jasan trend divergencije između kontinentalnih i alpsko-dinarskih populacija (slika 3). Najvarijabilnijim su se pokazale značajke: površina plojke, širina lista mjerena na 90 % dužine plojke i dužina peteljke. Za razliku od toga, najmanji stupanj varijabilnosti zabilježen je za varijable koje opisuju osnovu lisne plojke. Iako je trend variranja pojedinih značajki po populacijama bio sličan, u populacijama alpsko-dinarske regije zabilježena je nešto viša unutar-populacijska raznolikost. Kontinentalne populacije su imale veće vrijednosti svih mjerenih značajki lista u odnosu na populacije iz alpsko-dinarske regije. Analizom varijance, utvrđene su statistički značajne razlike između istraživanih regija te između stabla unutar populacija, dok su se populacije unutar regija razlikovale samo za četiri istraživane značajke (tablica 1). Unutarpopulacijska varijabilnost veća je od međupopulacijske varijabilnosti, što je odlika mnogih vrsta drveća. Multivarijatne analize potvrđuju postojanje jasne razlike između kontinentalnih i alpsko-dinarskih populacija bijele johe (slika 1, slika 4, tablica 3), što upućuje na mogućnost da istraživane populacije predstavljaju dva različita ekotipa. Morfološka udaljenost između populacija bila je korelirana s geografskom i ekološkom udaljenošću, što potvrđuje uzorak „isolation by distance“ i „isolation by environmental distance“. Drugim riječima, utvrđeno je da geografska udaljenost i ekološka divergencija imaju važan utjecaj na oblikovanje morfološke strukture populacija te da je ona posljedica njihove moguće lokalne prilagodbe na okolišne uvjete i njihove geografske udaljenosti (tablica 2). Dobivene spoznaje o varijabilnosti populacija mogu doprinijeti razvoju učinkovitijih planova očuvanja i gospodarenja sivom johom u Hrvatskoj. Kako bi se potvrdili dobiveni zaključci o varijabilnosti populacija sive johe dobiveni morfometrijskim metodama, istraživanja je svakako potrebno proširiti i na molekularno-biološke metode.

Bryological fi eld surveys in Plitvicka jezera National Park and adjacent areas (Slunjcica river and Vrhovinsko polje karst fi eld) carried out in 2012 and 2013 resulted in a list of 207 species (39 liverworts and 168 mosses). Two species are reported for the fi rst time from Croatia (Ephemerum minutissimum and Pohlia annotina). Six species are included in the Red data book of European bryophytes (Buxbaumia viridis, Dicranum viride, Hamatocaulis vernicosus, Anomodon rostratus,Rhynchostegiella tenuicaulis and Taxiphyllum densifolium). The first three are listed in the Bern Convention and the EU Habitats and Species Directive as well; in addition, other species, especially Sphagnum spp. rare in SE Europe were also located in the area.

Morfološka varijabilnost listova bijele (Alnus incana /L./ Moench) i crne johe (A. glutinosa /L./ Gaertn.) istražena je u pet prirodnih populacija na području Podravine i Međimurja, uz rijeke Dravu i Muru. Unutarpopulacijska i međupopulacijska varijabilnost utvrđena je na osnovi deset morfoloških značajki listova i četiri izvedena omjera, pri čemu su korištene deskriptivne i multivarijatne statističke metode. Provedenim istraživanjem utvrđena je visoka varijabilnost istraživanih populacija. Unutarpopulacijska varijabilnost veća je od međupopulacijske varijabilnosti kod obje vrste. Stabla unutar populacija signifikantno se razlikuju za sva analizirana svojstva. Klasterskom i kanoničkom diskriminantnom analizom dobiveno je jasno razdvajanje populacija bijele i crne johe, a na području Podravine utvrđena je prisutnost jedinki s prijelaznim značajkama koje odgovaraju hibridima među tim vrstama. U odnosu na roditeljske vrste, hibridi pokazuju intermedijarna svojstva za većinu istraživanih značajki. Populacije crne johe međusobno se signifikantno razlikuju u četiri istraživane značajke, dok se populacije bijele johe signifikantno ne razlikuju., White and black alder are our indigenous noble broad-leaved species. In Croatian forestry, black alder has an important place, while the white alder does not have economic importance and it is becoming increasingly neglected. White alder appears on shingle, active material in mainstream, on river banks and terraces which are periodically or at least sporadically flooded. It very rarely occurs on its own on drifts and it does not appear in swamp habitats which are characteristics of black alder. The farther the area is from the mainstream watercourse, the higher is the probability of black alder supervention. Finally, in swampy, peaty areas, black alder forms its stands.Stands of white and black alder are relatively clearly distinguished in the researched area, although somewhere is common their joint supervention on the same stands. In the areas where white and black alder habitats are overlapped, their spontaneous hybridisation is possible. White and black alder crosses have been so far noticed only in NW Croatia.Variability of a species is one of the most important preconditions for its adaptive potential in variable environment conditions, and in a long term, for survival of the species. That is, variability insures adaptability of populations towards environment changes through generations. The optimal variability of white and black alder in the area of riparian forest ecosystems is disturbed by negative anthropogenic activities.This paper researches the intra-population and inter-population variability of white and black alder in five natural populations along rivers Drava and Mura on the basis of morphological leaf traits.Material for the morphometric analysis was collected in five natural populations in the areas of Podravina and Međimurje, along rivers Drava and Mura (Figure 1). Three populations of white alder and two populations of black alder were included in the research. Each population was represented by 20 trees and each tree by 20 healthy and undamaged leaves, collected from short fertile shoots of the outer, light-exposed part of tree top. The leaves were scanned and measured by the WinFolia programme. Ten foliar traits were defined and measured altogether (Figure 2). From the measured traits, the following ratios were derived: MPW/BL, PW1/BL, PMPW/BL, PL/BL.The measured morphological traits were shown through descriptive statistical parameters. For determining the intra-population and inter-population variability, the univariate analysis of variance was used. For determining similarities or differences of analyzed populations on the basis of measured morphological leaf traits, multivariate statistical methods were used – cluster and discriminant analysis. These statistical analyses were conducted using the statistical programme STATISTICA 8.0.The results of the descriptive statistical analysis are presented in Table 1, by population. For both species, the trees within populations differ significantly on all analysed traits (Tables 2 and 3). Populations of white alder do not differ significantly between themselves on any trait, while the differentiation of populations of black alder is at significant level 0,01 inherent for variables BL, PMPW, LA1 and LA2. For each species individually, smaller variability among populations has been determined, while the remaining component regarding variability of the leaves within the tree takes up the largest proportion of the total variance (Tables 4 and 5).It can be seen from the dendrogram that the inter-population variability of black alder is greater than the inter-population variability of white alder (Figure 3).In order to determine which traits best discriminate researched populations and to additionally clarify the trend of their differentiation, discriminant analysis was conducted (Tables 6 and 7, Figure 4). For the populations of white alder, it was determined that canonical projections of trees within populations are weakly connected, in the sense that the populations are almost completely overlapping. The weak differentiation between populations and great variability within populations can be explained by similar ecological conditions of their supervention and by intensive flow of genes between populations. Although the canonical value projections for individual trees are partly overlapping, the trend of differentiation between populations of black alder is clearly perceived. Considering that the researched species belong to different river and forest systems, we can assume that the obtained differences in variability are caused by hydrological and ecological influences.Although the trees of white and black alder clearly differ between themselves, it can be seen that individual trees from white alder population Varaždinsko jezero cross to the right side of the diagram (Figure 4). Considering that the mentioned trees are intermediary in relation to researched species, we can conclude that it is the case of hybrid individuals. Through subsequent analysis, intermediary traits on most researched variables were identified for the crosses (Table 8).Genetic diversity is one of the basic preconditions for adaptability of a certain species to particular habitat conditions. Through this research, the knowledge of the intra-population and inter-population variability of white and black alder on Podravina – Međimurje area was gained. This knowledge represents the basis for further research that needs to be conducted in order to obtain guidelines for improvement and preservation of genetic resources of the alder species in Croatia.

Global climate changes, regardless to the origin (natural condition or anthropogenic effect) are actual appearance in Earth. Models predicting global climate changes contain large entropy because they do not include all those factors and their mutual interaction that have direct or indirect effect on climate. According to Hays (1976) global climate changes are effected by regular cycles (so called Milanković cycles) in Earth orbit which appear in almost regular amplitudes at 100000 years. Due to it is observed shift of cold and warm periods in Earth history. Warm periods (interglaciations) repeat every 100000 years, and last approximately 10000 years (Berger, 1981). Precisely shift of warm and cold periods in Earth history significantly effects on composition and quantity of vegetation on Earth (Willis et al., 1999). Due to global changes some tree species show regressive changes (decrease of spatial distribution) of ecological niche, while others show positive direction of changes observed as increase of ecological niche spatial distribution. Climate factors, such as maximum temperature of the hottest month and minimum temperature of the coldest month, as well as precipitation of the driest and the wettest month represent limiting values of climate factors that effect on accrurence of species. Results of the paleobotanic researches point out significant suppression of one tree species when others are spreading. According to research of Reille (1995), common beech (Fagus sylvatica) has during Holocen suppressed common hornbeam (Carpinus betulus) dominating species of the temperate zone European forests in Emiana period (130000 years ago) when forest vegetation was distributed up to toadys boreal areas with dominating tundra vegetation. Also, according to West (1980) in Pastonian period (early to middle Pelistocen) species Picea omorika was distributed up to today’s south of England, and today species population has extremely relict character. When talking about relation between vegetation and climate it should be considered that vegetation indirectly effects and changes climate conditions in certain area, through processes of assimilation and storaging atmosphere CO2 (Laubhann et al., 2008). Therefore changes of climate that is climate factors cause changes of certain part species ecological niche. Whereat it is difficult to distinguish and completely explain only effect of climate factors on species ecological niche and by that spatial distribution of the same. Example for that is species pedunculate oak (Quercus robur) for which accurence especial importance has underground and flood water. But total pedunculate oak (Quercus robur) population from all other species in this research has shown the narrowest range of values according to used climate factors. According to average maximum temperatures of the hottest month pedunculate oak accrue in range at only 2,0 ºC that is 2,3 ºC for average minimum temperature of the coldest month (climate data in period 1950-2000). In contrary to pedunculate oak, common beech (Fagus sylvatica) shows much higher range of average maximum temperatures of the hottest month at 13,6 ºC and 8,9 ºC for average minimum temperature of the coldest month. Exactly this kind of relations point out wideness of certain tree species ecological niche, so that according to extreme temperature values, common beech (Fagus sylvatica) is species of wide ecological

U široj okolici Zavižana na sjevernom Velebitu, S. Bertović je (1975) opisao smrekovu asocijaciju sa šarenkastom šašuljicom (Calamagro­stio variae-Piceetum dinaricum Bertović 1975). Naziv je asocijacije nelegiti­man (čl. 31. i 34a, Međunarodni kodeks fitocenološke nomenklature /ICPN/, Weber, Moravec i Theurillat 2000) pa je u radu naziv promijenjen u Hyperico grisebachii-Piceetum abietis (Bertović 1975) nom. nov. hoc loco i tako nomen­katurno revidiran. Osim toga, fitocenoza je istražena na širem području Dina­rida u Hrvatskoj te uspoređena sa srodnim smrekovim zajednicama subalpskoga pojasa, uz određivanje dijagnostički važnih vrsta., Common beech (Fagus sylvatica) forms a strong vegetation belt in the sub-alpine region of the Croatian Dinaric range, with natural forests of com­mon spruce (Picea abies) occurring as azonal communities in some specific locali­ties of this belt. The association Laserpitio krapfii-Piceetum Vukelić, Alegro etŠegota 2010 inhabits sinkholes and northern, colder and shadier slopes from 1,100 to 1,400 m above the sea, while shady and open ridges and peaks above 1,400 m are occupied by the spruce forest described by S. Bertović (1975) under the name of Calamagrostio variae-Piceetum dinaricum Bertović 1975. Bertović’s name of the association is illegitimate (articles 31 and 34a, International Code of Phytocoeno­logical Nomenclature - ICPN, Weber, Moravec and Theurillat 2000) since the name was already used by Schweingruber in 1972 for an association in the Randalpen in Switzerland. One of the objectives of this research was to revise the nomenclature and propose a new name for the phytocoenosis (Hyperico grisebachii-Piceetum), as well as define the diagnostic species and other features. We used a method of the Zurich-Montpellier Phytocoenological School with a six-degree scale. The floral composition was classified according to the social affiliation of the species. The plant nomenclature was adjusted to the Flora Croatia database (Nikolić 2010), while mosses were adjusted according to Koperski et al. (2000). The association Hyperico grisebachii-Piceetum is distributed above an altitude of 1,400 m (slightly lower on Samarske Stijene). It grows on distinctly rocky peaks, ridges, hooks, karrens, and upper, steep and sun-exposed slopes. The sites of this association are basically characterized by the rockiness of the terrain, which al­most always exceeds 40 %. This contributes significantly to the broken tree canopy layer and to the composition of shrubs and ground vegetation (Figure 1). The soils mostly consist of different subtypes of calcomelanosol, from organogenic, over or­ganomineral to browned soils, and less frequently of shallow calcocambisol (Ba­kšić et al. 2010). According to the macroclimatic features of the Zavižan set, the average annual temperature is 3.5 oC and the average annual precipitation amount is 1,898 mm (Vučjak meteorological station on Northern Velebit – 1,594 m, period 1061 – 1990). The ecological amplitude of the occurrence of the community is very narrow, whereas the specific relief, pedological and climatic conditions are unfa­vourable for the successful growth of forest vegetation. Ten phytocoenological relevés (Table 1, relevés 1– 6, Zavižan area; 7 and 8, Smrčeve Doline area; 9 and 10, Samarske Stijene area) contain 153 species of hig­her plants and 31 moss species. The interrupted tree layer is completely dominated by spruce, while the shrub layer, in addition to the species from the tree layer, con­tains further 18 species. Lonicera caerulea inc. subsp. borbasiana, Clematis alpina, Vaccinium myrtillus, Rosa pendulina, Salix appendiculata, Rubus idaeus, Sambu­cus racemosa and Juniperus communis subsp. alpina feature in more than two thirds of the relevés. From the sociological standpoint, there is a prevalence of so-called “picetal” (spruce) species, characteristic for spruce forests of the major part of Europe. Together with mosses, there are 38 such species in all. They are de­cisive for the sin-systematic position of the association and their participation is higher than in the marginal phytocoenosis Laserpitio krapfii-Piceetum. The species Calamagrostis varia, Cirsium erysithales, and even Carex ornithopoda, which be­long to the order Erico-Pinetalia, deserve special mention in terms of participation and cover. Of other higher categories, the order Fagetalia Pawl. 1928 and lower categories consist of 31 species, of which 7 occur in over 40 % of the relevés. The alliance Adenostylion Br.-Bl. 1925 and the order Adenostyletalia G. & J. Br.-Bl. 1931 are represented by 17 species, with 5 species occurring in over 40 % of the re­levés. The species of these syntaxa occur in a considerably lesser amount than is the case with the phytocoenosis Laserpitio krapfii-Piceetum mentioned above. The comparison of the newly-nominated phytocoenosis Hyperico grisebachii-Pi­ceetum with Shwaingruber’s Calamagrostio variae-Piceetum shows big differences, as well as their absolute independence. Over thirty species from the Dinaric Alps (e.g. Salix appendiculata, Sambucus racemosa, Lonicera caerulea subsp. borbasiana, Festuca bosniaca, Hypericum richeri subsp. grisebachii, Cardus acanthoides, Gera­nium macrorrhizum, Achillea clavene, Gentiana lutea subsp. symphyandra, Ribes alpinum and many others) are missing from stands of spruce forest with small-reed in the Austrian Alps (Willner and Grabherr 2007, columns 7 and 8, Table 34). On the other hand, these stands contain more than 100 species which were not recorded in the Dinaric association. Of these species, Larix decidua, Pinus sylvestris, Polygala chamaebuxus, Sesleria albicans, Homogyne alpina, Carex alba, Hepatica nobilis, Erica carnea, Campanula cochleariifolia, Ranunculus nemorosus and others are particularly prominent in terms of occurrence or participation. The investigated spruce association differs from subalpine spruce forests growing in Slovenia (Zupan­čič 1999) and in other Dinaric regions (Vukelić, Alegro and Šegota 2010). To select diagnostic species of the association, we compared ten relevés from Table 1 and used the results of research into the forest vegetation of south-eastern Europe, primarily that of Fukarek (1964), Stefanović (1970), Zupančič (1980, 1999),Zupančič and Acceto (1994), Vukelić, Alegro and Šegota (2010) and other phytocoe­nologists. Special mention should be made of a broader group of differentiating spe­cies which characterize the subalpine, open-canopy rocky sites and which either do not occur in other spruce communities or are present to a much lesser degree. These include in the first place Juniperus communis subsp. alpina, Salix apendicullata, Sambucus racemosa, Hypericum richeri subsp. grisebachii, Achillea clavenae, Gen­tiana lutea subsp. symphyandra, than Festuca bosniaca, Cardus acanthoides, Car­lina acaulis subsp. caulescens, Asplenium fissum, Melampyrum velebiticum and others. Not all of them are primarily forest species; the sites of this spruce forest are frequently interspersed with mountain clearings and massive blocks whose cracks are inhabited by these species. In relation to other spruce forests in Croatia and wider, there is also a group of forest species with high participation and cover that includes Calamagrostis varia, Polystychum lonchitis, Adenostyles alpina and Vacci­nium vitis-idaea. These species play an important role in the identification and diffe­rentiation of this association, although they cannot be determined as differentiating since they are also present in other Dinaric phytocoenoses. St John’s wort, Hypericum richeri Vill. subsp. grisebachii (Boiss.) Nyman, pro­ved to be the most suitable species for nominating the association. Its participation and amounts are much higher than in the related phytocoenoses, while its eco-indi­cator properties are ideally suited to the site conditions of the association. Moreo­ver, it has not been used in the nomination of common spruce communities. In forest communities of Croatia, Hypericum richeri subsp. grisebachii is found in mugo pine stands and in the investigated spruce association. Regardless of the same sin-systematic affiliation, these two associations differ profoundly. Based on the above, the valid name of the analyzed association is Hyperico gri-sebachii-Piceetum abietis (Bertović 1975) nom. nov. hoc loco. We propose Berto­vić’s relevé No 5 in Table 17 (Bertović 1975, p. 34) to be the nomenclatural type (lectotypus hoc loco), This will solve the problem of the name and independent sta­tus of the association. In the syntaxonomic sense, it belongs to the alliance Vacci­nio-Piceion, order Vaccinio-Piceetalia and class Vaccinio-Piceetea. The phytocoenosis does not have any commercial importance, but is of high pro­tective and natural-scientific significance. The most important stands are found in North Velebit National Park, but the association also occurs sporadically in Sa­marske Stijene on Bjelolasica and in the Smrekovac area in the Risnjak massif. The composition of the phytocoenosis is not uniform across the entire distribution range. The high ridges on which it grows are relatively distant enclaves with their specific geobotanical and horological features.

Phytocoenological traits of forests of sessile oak in the area of Zrinska Gora were investigated in 2009. Phytocoenological research was conducted using a method of the Zurich-Montpellier School. A comparison was made with acido-thermophilic forests of sessile oak from central and north-western Croatia, then from Slovenia and the Mescek Mountains in Hungary. A statistical comparison was made by entering all the phytocoenological relevés into the Turboveg database. This was followed by a classical synthetic analysis of the phytocoenological relevés and a multivariate analysis using Syntax 2000 software. Average Ellenberg’s values were calculated for each relevé with JUICE 6.3 software . The obtained data were processed with STATISTICA 8.0. Taking into consideration all the facts it can be concluded that the newly established association Potentillo micranthae-Quercetum petraeae shows a high degree of independence and differentiation from other similar associations described to date. In relation to others, it is poorer in species, both in terms of systematic categories to which it belongs and the number of elements from the orders of Fagetalia and Quercetalia pubescentis. Of the species occurring in acidophilic forests of sessile oak, Genista tinctoria, Chamaecytisus hirsutus and Dicranella heteromalla can be considered characteristic species, whereas Galium sylvaticum, Cephalanthera longifolia, Dianthus armeria and Viola alba can be termed differentiating species. The species Potentilla micrantha, Festuca drymeia and Luzula forsteri are very important for the structure, physiognomy and syndynamics of the association. It is subordinated to the alliance Quercion robori-petraeae, the order Quercetalia robori-petraeae and the class Querco-Fagetea.

The paper presents vegetation research of grey alder stands (Alnus incana /L./ Moench) along the beds of the rivers Kupa, Kupica, Čabranka and Belica in Gorski kotar. The standard Central European phytosociological method was used to record and analyze eight phytosociological relevés from 2010. Research results revealed that it was the association of grey alder with deadnettle, Lamio orvalae-Alnetum incanae, recently recorded in the west of Slovenia (DAKSKOBLER, 2007, 2010). Growing under similar ecological conditions and containing common diagnostic species as the Slovenian stands, the stands in Gorski kotar are characterized by the abundant presence of Helleborus dumetorum. For this reason, they have been classified as a new geographic variant of the above mentioned association., U radu su prikazana vegetacijska istraživanja sastojina bijele johe (Alnus incana /L./ Moench) uz korita rijeka Kupe, Kupice, Čabranke i Belice u Gorskome kotaru. Pri tome je korištena standardna srednjoeuropska fitocenološka metoda kojom je snimljeno i analizirano osam fitocenoloških snimki iz 2010. godine. Rezultati istraživanja pokazali su da se radi o asocijaciji bijele johe s mrtvom koprivom Lamio orvalae-Alnetum incanae, nedavno ustanovljenoj u zapadnoj Sloveniji (DAKSKOBLER, 2007, 2010). Uz slične ekološke uvjete i zajedničke dijagnostičke vrste, sastojine iz Gorskog kotara odlikuju se obilnom nazočnošću vrste Helleborus dumetorum, pa su izdvojene kao nova geografska varijanta spomenute asocijacije.

Obična jela jedna je od najvažnijih gospodarskih vrsta drveća u Hrvatskoj. Rasprostranjena je na području Dinarida i na panonskom gorju. Globalne klimatske promjene izazivaju opravdanu bojazan u mogućnost sma njenja ekološke niše obične jele u Hrvatskoj. U ovom su istraživanju analizirani određeni ekološki čimbenici koji izgrađuju ekološku nišu unutar područja pridolaska jele. Korišteni globalni klimatski model podrazumijeva dvostruko povećanje koncentracije stakleničkih plinova (CO2, CH4, N2O, CFC-11 i CFC-12) unutar da našnjega areala obične jele u razdoblju 2000 – 2100. godine, iz čega proizi la zi povećanje prosječne godišnje temperature za ~ 2,5 °C i smanjenje prosječ ne godišnje količine oborina za ~ 152 mm/god. u odnosu na razdoblje 1950 – 2000. godine. Istraživanje je pokazalo kako bi ove promjene mogle pro uzročiti smanjenje ekološke niše obične jele u Hrvatskoj (p>0,9) za gotovo 85 % u odnosu na današnje stanje., The aim of this research is to determine the following: the fundamental ecological niche or potential distribution range of silver fir in Croatia on the basis of selected climatic factors, differences between parts of fir distribution range with reference to the selected climatic factors and changes in the ecological niche in terms of the climate change model for the period 2000 – 2100. Climatic data for the period 1950 – 2000 used in this work were taken from the Worldclime database (Hijmans et al. 2005). Eight climatic variables and relief factors were employed to construct the prognostic model, such as altitute (m), slope (°) and others. Highly correlated variables were rejected. To predict climate changes for the period 2000 – 2100, a CCM3 model (Climate Change Model) was used, which is based on double the current level of greenhouse gases (CO, CH 4, N2O, CFC-11 and CFC-12) (Govindasamy et al. 2003). All climatic data in grid form were 2entered in 30-second resolution (~ 1 km2). Data on fir occurrence in Croatia were taken from the latest research on the distribution of forest sites (Vukelić et al. 2008), ICP plots, phytocoenological relevé database of the Republic of Croatia and management plans. In each plot fir occurrence was graded with binary variables – 1 (present) and 0 (absent). Independent variables used to construct the logistic model and prediction included elevation – Elev (m), slope – Slope (°), mean annual temperature – MeanAnnT (°C), mean annual temperature range – MeanAnnTR (°C), obtained as the difference between the mean temperature of the warmest and the coldest month, then the ratio between the mean monthly temperature range and the mean annual temperature range – IsoTherm (°C), mean temperature of the driest quarter - MeanTDQ (°C), mean temperature of the coldest quarter – Mean TCM (°C), mean annual precipitation quantity – MeanAnnP (mm), mean annual precipitation in the warmest quarter – MeanPWQ (mm) and coefficient of seasonal precipitation variation – PreS (mm). The distribution range of fir was divided into three parts: DIN – the Dinaric part of fir range within the community Omphalodo-Fagetum /Tregubov 1957/ Marinček et al. 1993, ACD – the Dinaric part of acidophilic fir communities (Blechno-Abietetum Horvat /1938/ 1950) and PAN – the Pannonian part encompassing fir range within the community Festuco drymeiae-Abietetum (Vukelić et Baričević 2007). Discriminant analysis (DA) was used to analyze and visualize ecological niches within the range. The prognostic model of ecological niches for the current distribution range of fir and that for the period until 2100 with regard to climate change model was made by means of logistic regression (LOGREG), expressions: p(y)= exp(LP)/(1+exp(LP)), where LP represents linear combination of independent variables (Flantua et al. 2007). According to the research, the current range of silver fir in Croatia does not differ dramatically (p . 0.9) from the potential one. This suggests that longlasting forest management did not contribute to its reduction. However, the selected climatic factors could have a signficant effect on the occurrence of silver fir in Croatia. The prognostic model shows that in conditions of global climate changes its potential range (p = . 0.9) in Croatia could decrease by ~ 85% in the period 2000 – 2100.

Bukovo-jelove šume u gorju jugozapadnoga dijela Panonije u Hrvatskoj fitocenološki su nedovoljno istražene. U novije vrijeme nije bilo njihove podrobne nomenklaturno-sintaksonomske analize koja bi u potpunosti bila sukladna međunarodnim nomenklaturnim pravilima (Barkman i dr. 1986, Weber i dr. 2000). Zbog toga smo nakon njihova odvajanja od dinarskih bukovo-jelovih šuma (Vukelić i Baričević 1996) pristupili 2007. godine njihovu istraživanju, imenovanju i određivanju prema ostalim šumskim zajednicama ovoga dijela Europe. U glavnom arealu bukovo-jelovih šuma na Maclju, Medvednici i Papuku fitocenološki smo istražili i snimili četrdeset ploha, a u ovom radu prikazujemo ih 25. Prilično su bogata flornoga sastava s ukupno 135 vrsta. Prevladavaju vrste reda Fagetalia i njegovih nižih jedinica, od kojih su posebno značajne vrste sveze Aremonio-Fagion. Florni sastav, ekološki uvjeti, fizionomija ovih sastojina i način gospodarenja njima opravdavaju izdvajanje zasebne asocijacije. Označili smo ju imenom Festuco drymeiae-Abietetum (bukovo-jelova šuma s brdskom vlasuljom) prema najproširenijoj i sociološki važnoj vrsti Festuca drymeia i edifikatoru jeli (Abies alba). Time se jasno odvaja i prepoznaje među ostalim bukovim i bukovo-jelovim asocijacijama unutar sveze Aremonio-Fagion i podsveze Lamio orvalae-Fagenion kojima je podređena. Tipološki smo ju raščlanili na dvije subasocijacije (lunarietosum redivivae i festucetosum drymeiae) koje se ekološki i po flori jasno razlikuju. Sastojine u sjeverozapadnom dijelu Hrvatske, na Maclju i Medvednici po flornom sastavu su raznovrsnije i bogatije od sastojina na Papuku, poglavito vrstama sveze Aremonio-Fagion, no statistička analiza nije pokazala opravdanost njihova razdvajanja. U radu su ukratko raspravljene i fitogeografske razlike unutar areala asocijacije u Hrvatskoj i odnos prema srodnim zajednicama na istraživanom području i na susjednim područjima., Forests of beech and fir in the mountains of north-western part of the Pannonian valley in Croatia represent zonal communities of the mountainous belt. They have a relatively rich floral composition in which species of the order Fagetalia and its lower units have distinct prominence. Covering about fifteen thousand hectares, they grow in humid-perhumid conditions of temperate warm climate with a favourable precipitation pattern. The geological-lythological structure is predominantly made up of silicate rocks (sandstones, slates) with a dominant soil type of dystric cambisol with acid reaction. In northern expositions they take up altitudes between 600 and 1,000 m, while in southern expositions they climb down to as low as 300 m. Phytocoenological research and relevés of 40 plots were made in the main distribution range of beech-fir forests on Macelj, Medvednica and Papuk, 25 of which will be presented in this paper. They have a relatively rich floristic composition containing a total of 135 species. There is a prevalence of species of the order Fagetalia and its lower units, of which species of the alliance Aremonio-Fagion are particularly important (Table 1). The floristic composition, ecological conditions, physiognomy and method of managing these stands justify their classification into a separate association. It was named Festuco-drymeiae-Abietetum (forest of beech and fir with fescue) according to the most widely represented and sociologically important species Festuca drymeia and the edifier fir (Abies alba). This clearly distinguishes it from other beech and beech-fir associations within the alliance Aremonio-Fagion and suballiance Lamio orvalae-Fagenion, to which it is subordinated. Abies alba, Fraxinus excelsior, Cardamine trifolia, Lunaria rediviva, Geranium robertianum, Galeopsis tetrahit, Cephalanthera damasonium and Glechoma hirsuta are differentiating species of the association. It has been typologically divided into two subassociations: at steeper, drier terrains and plateaux it is festucetosum drymeiae, while at more humous, less acid, fresher and shadier positions it is lunarietosum redivivae. Comparative analyses have shown an independent nature of the association in relation to other ones that occur in the montane beech belt of the Pannonian part of Croatia and adjacent areas (Table 2). Stands in the north-western part of Croatia, on Macelj and Medvednica, are floristically richer and more diverse than those on Papuk – particularly in species of the alliance Aremonio-Fagion. However, statistical analysis did not justify their separation.

Crna joha (Alnus glutinosa) raste u okolici Đurđevca u Podravini u čistim i mješovitim sastojinama na približno 2000 ha i važna je gospodarska vrsta drveća. Podravske sastojine nadaleko su poznate po bujnom uzrastu, visokovrijednom drvu, a s fitocenološkoga stajališta po prirodnom, raznovrsnom i bogatom sastavu. U svojoj disertaciji Glavač (1960) je detaljno istražio i opisao dvije asocijacije u kojima prevladava crna joha: na staništima koja su poplavljena stajaćom vodom utvrđena je fitocenoza crne johe s dugoklasim šašem (Carici elongatae-Alnetum glutinosae), a na nju se sukcesivno nadovezuje mnogo suša zajednica crne johe i poljskoga jasena sa sremzom (Pruno-Fraxinetum). Obje su asocijacije bile prije toga istražene i opisane u Europi. Glavač je fitocenoze prikazao u sintetskim tablicama s 28 snimaka, utvrdio je njihov florni sastav, sistematsku pripadnost, sindinamiku, raščlanjenost i ostale značajke. Od Glavačevih istraživanja u proteklih pedesetak godina izgrađene su hidrocentrale na rijeci Dravi, promijenjeni ostali ekološki uvjeti i obnovljena većina crnojohovih šuma. To nas je ponukalo da recentnim fitocenološkim istraživanjima pokušamo utvrditi posljedice promjena na građu, dinamiku i strukturu sastojina u dvjema spomenutim asocijacijama. Na temelju 26 fitocenoloških snimaka i ostalih relevantnih podataka općenito smo utvrdili promjene u flornom sastavu u smjeru nestajanja hidrofita i higrofita i proširenju vrsta suših staništa, sukladno tomu znatnu promjenu odnosa površina istraživanih zajednica, njihova sindinamskoga razvoja i raščlanjenosti. U članku se govori i o problematici i potrebama detaljne fitocenološke razrade ostalih crnojohovih šuma u Hrvatskoj koje su istraživane relativno ekstenzivno i opisane u četiri asocijacije. U tom smislu obrazlaže se potreba šire analize i nastavka istraživanja., Forests of common alder in Croatia cover approximately 8000 ha (Prpić and Milković 2005). The most valuable stands are found in the management unit Đurđevačke nizinske šume in Podravina. In this area common alder forms pure or mixed stand extending over about 2000 ha. The stands manifest distinctly regular growth of good quality. From a phytocoenological aspect they are characterized by a natural, diverse and rich composition. The two associations dominated by common alder were studied and described in detail by M. Glavač in his dissertation of 1960. These associations include the phytocoenosis of common alder and elongated sedge (Carici elongatae-Alnetum glutinosae) growing in floodplain sites with stagnant water and micro-depressions, and a much drier community of common alder and narrow-leaved ash with birdcherry (Pruno-Fraxinetum) continuing onto the former community. There have been many changes in the past fifty years elapsing since the research by Glavač, including the construction of hydropower stations on the river Drava, drastic ecological transformations and regeneration of the majority of common alder forests. We have undertaken phytocoenological research in order to assess the consequences of the changes on the structure, dynamics and composition of these two associations. The planned field research was carried out in the vegetation period of 2006 using the standard method of the Braun-Blanquet school. In doing so, we were able to analyze and compare the findings, since former research was also conducted using the same method. Stands with a stable floral composition aged 50 and over were used for relevés. The relevés were sized 20 × 20 m on average. A total of 28 relevés were made: 7 in the forest of common alder with elongated sedge and the rest in the association Pruno-Fraxinetum. Mosses were not considered. The forest of common alder with elongated sedge (Carici elongatae-Alnetum glutinosae W. Koch 1926) in Podravina grows on peat and base-rich, humus gleyic soils saturated with water, which separate this community from the adjacent ones. The basic factor in the development of this community is the dynamics of groundwater oscillations. Here, alder is in its optimal stage of development. Preserved here since the glacial period, it has a relict character. It is classified into three subassociations: iridetosum pseudacori occurring in the wettest sites, where alder forms high cones surrounded with water almost throughout the year, polygonetosum hydropiperis growing in wet soils with a highly developed humus layer, and cornetosum sanguineae growing in relatively drier soils in progression. The floral composition of the community is given in Table 1, which contains 7 of our own relevés and 13 relevés by Glavač from 1960 showing a degree of participation. According to the research, the range of the forest Carici elongatae-Alnetum glutinosae has decreased manifoldly. Only some fragments have remained in water-covered depressions smaller than half a hectare from which water cannot escape. A comparison of the community’s floral composition some fifty years ago and today (Table 1) reveals changes not only in the size of the area but also in the composition of the plant species. There are fewer hygrophytes and species of swampy depressions with long-lasting stagnant water, such as Carex elongata, Poa palustris, Lythrum salicaria, Valeriana dioica, Rorippa amphibia, Calystegia sepium, Mentha aquatica, Carex vesicaria, and Glyceria fluitans, whereas some species, e.g. Spiraea salicifolia, have already disappeared. The natural syndynamic development has also stopped, so that only a subassociation with Iris pseudacorus can currently be identified. The other stands have already been converted to Pruno-Fraxinetum. The forest of common alder and narrow-leaved ash with birdcherry (Pruno-Fraxinetum Oberdorfer 1953) is formed by the succession from the previous association. It grows on drier and elevated terrains. It belongs to the order Fagetalia due to the lack of hygrophytes and the prevalence of mezophilic species. The floral composition of the community is given in Table 2. The first column shows 15 relevés by Glavač and the second 19 relevés from this research. A comparison of the phytocoenological relevés shows an increased proportion of mezophilic species and an absence or a reduced number of the species that indicate swampy and very wet forests. The species occurring less frequently are Galium palustre, Ranunculus repens, Lycopus europaeus, Poa trivialis, Valeriana dioica, and Potentilla reptans, while on the other hand Sambucus nigra, Corylus avellana, Prunus padus, Mercurialis perennis, Paris quadrifolia, Anemone nemorosa, Leucojum vernum, Galeobdolon luteum and Lamium purpureum have grown in number. Some particular sites currently feature Acer pseudoplatanus and Daphne mezereum, species that are not typical for the lowland area of Croatia. In the past fifty years, the area under these associations has increased considerably. The name and the description of the association originate in Central Europe, where these stands contain Fraxinus excelsior instead of Fraxinus angustifolia. For reasons of this and other differences, this community must be analyzed in detailed and compared with the Central European community. Its position in the phytocoenological nomenclature and systematics must also be determined. Changes in the stands of common alder occurring in the past fifty years are primarily the consequence of the synergy of altered ecological factors and anthropogenic factors, i.e. stand management. Although the groundwater levels in the forest stands being investigated are still relatively favourable (Fig. 3), the newly built hydropower stations in Slovenia and Croatia have generally altered the water regime. The main problem facing the remaining wet areas of the river Drava in Slovenia and Croatia is the low water level amounting to only 2.4 % of the average water flow. Additional problems include significant oscillations of the river and the erosion of the riverbed. In the past 100 years the water surface area has decreased by 65 %, whereas open sites such as river islands and pebbly and sandy shoals have decreased by as much as 92 % (Schneider-Jackoby 2006). Another important factor in the analysis of the condition and changes in the forests of the study area is the type of management, or more accurately, the regeneration method applied on the stands of common alder. Stands over 80 years old are cut in a single treatment and the site is cleared and regenerated with seedlings of common alder in the same year. Although such an approach is highly efficient, cheap and good from a silvicultural standpoint, it does not take sufficient account of the ecological, vegetational and other specific features and differences. This results in the uniformity of the stands and sites and a decrease or disappearance of some species – primarily hydrophytes and hygrophytes. Moreover, the natural onset, participation and growth of other species, such as the narrow-leaved ash and even pedunculate oak, are slowed down. Changes caused by the construction of roads and the adjacent canals, as well as a direct human impact, constitute another important factor.

U radu se fitocenološki analiziraju mješovite sastojine jele i crnoga graba (Ostryo-Abietetum/Fukarek 1963/Trinajstić 1983) u vinodolskom zaleđu. Iako su već istraživane (Rac 1995) u fitocenološkom smislu je izostala cjelovita analiza i usporedba s ostalim područjima Hrvatske. Zajednica je predstavljena s deset snimaka načinjenih u očuvanijim i suvislijim kompleksima na približno 250 ha njezina rasprostranjenja i nadmorskim visinama od 700 do 900 m. Ukupno su registrirane 84 vrste, prosječno po snimci 41, a njihova sociološka pripadnost relativno je složena, što su pokazala i prijašnja istraživanja na Biokovu (Trinajstić 1983, 1987). U odnosu na biokovske sastojine zabilježene su 54 nove vrste, a izostaje 46, među njima Pulmonaria visianii i Lonicera alpigena izdvojene kao svojstvene vrste asocijacije. U sloju drveća dominira Abies alba, podstojno i Ostrya carpinifolia, a u sloju grmlja pridolaze 34 vrste, bujnošću dominiraju one termofilne svojstvene za red Quercetalia pubescentis. U sloju prizemnog rašća prevladavaju mezofilne vrste reda Fagetalia i sveze Aremonio-Fagion i termofilna vrsta Sesleria autumnalis. Također je za vinodolske sastojine specifičan pridolazak hrasta kitnjaka i nekih drugih vrsta slabije izražene socijalne pripadnosti i mezofilnoga karaktera. Sastojine zajednice Ostryo-Abietetum su uglavnom zaštitne panjače trajno otvorenog sklopa i obrasta uglavnom oko 50 %., In Croatia, the forest community Ostryo-Abietetum (Fukarek 1963) Trinajstić 1983 was found on Mt. Biokovo (Trinajstić 1983, 1987) and on Kapela (Rac et Lovrić 1987, Rac 1995). Only five relevés have been published in scientific literature. Since the floral composition has not been analyzed and compared in more detail, the studied phytocoenosis is insufficiently known. Phytocoenological research was conducted following the classical principles of the Braun-Blanquet School (1964). Forests of fir with hop hornbeam were presented on the basis of ten relevés from the Vinodol area and five from Biokovo. Plant nomenclature was adjusted according to Ehrendorfer (1973), while plant-sociological affiliation and biological form of the species were based on the work generally used for this purpose. Phytocoenological research into the stands of the community Ostryo-Abietetum in Vinodol showed syntaxonomic affiliation in the sense of Marinček et al. (1993) in accordance with international syntaxonomic rules (Weber et al. 2000). A total of 84 species were registered in ten phytocoenological relevés. On average, there were 41 species per relevé. Abies alba prevails in the dominant layer, Ostrya carpinifolia in the intermediate layer and thermophilic species of the order Quercetalia pubescentis in the shrub layer. The layer of herbaceous vegetation is dominated by the species of the order Fagetalia and the alliance Aremonio-Fagion and by the thermophilic species Sesleria autumnalis. The forest phytocoenosis of fir with hop hornbeam occurs over approximately 250 ha in the study area (Racić 2001). Compared to past phytocoenological relevés of this community in Croatia, 54 new species have been registered. Those of mesophilic character and beech forests prevail, which completes the knowledge of the phytocoenosis Ostryo-Abietetum. In relation to the stands on Biokovo, 46 species of predominantly thermophilic character are absent, including Lonicera alpigena and Pulmonaria visianii, which were initially classified as characteristic species of the association. The species Hepatica nobilis, with frequent presence of sessile oak in the tree layer, occurs abundantly in Vinodol stands. Stands of the community Ostryo-Abietetum are mainly protective coppices with a permanently open canopy and density of about 50 %.

The willow-like meadowsweet (Spiraea salicifolia L.) is an extremely rare shrub in the forest associations of Croatia. After investigating the forest vegetations of Croatia for many years, and analyzing numbers of phytocoenological surveys of other authors, we have so far established only three forest locations where this species grows: Drežničko Polje in the wider Ogulin area; the area of Česma near Vrbovec and the Đurđevac lowland forests near the Podravina village of Kalinovac (Fig. 1). On the first location, it grows in the association of Genisto elatae-Quercetum roboris Horv. 38; on the second, Frangulo-Alnetum glutinosae Rauš 69, and the third, in the phytocoenoses of Pruno-Fraxinetum Oberd. 53 and Carici elongatae-Alnetum glutinosae Koch 26. The habitats of these associations are of higher or lesser depression and are occasionally flooded. Spiraea salicifolia has not been clearly defined sociologically, and Central European authors classify it as a characteristic species of the alliance Pruno- Rubion fruticosi Doing 62. Two localities in the forest associations in which these species appears have therefore been proclaimed special forest vegetation reserves, whereas the Česma locality has recently been recommended for such protection., Vrbolika suručica (Spiraea salicifolia L.) vrlo je rijedak grm u šumskim zajednicama Hrvatske. Dugogodišnjim vlastitim istraživanjima šumske vegetacije Hrvatske i analizom velikog broja fitocenoloških snimaka ostalih autora ustanovili smo zasad samo tri šumska lokaliteta na kojima ta vrsta raste: u Drežničkom polju na širem području Ogulina, u predjelu Česma kod Vrbovca i u đurđevačkim nizinskim šumama kod podravskog sela Kalinovca (si. 1). Spiraea salicifolia (si. 2) na prvom je lokalitetu rasprostranjena u zajednici Genisto elatae-Quercetum roboris Horv. 38 (si. 3), na drugom u Frangulo-Alnetum glutinosae Rauš 69, a na trećem u fitocenozama Pruno-Fraxinetum Oberd. 53 i Carici elongatae-Alnetum glutinosae Koch 26. Staništa su tih zajednica manje ili veće depresije i povremeno su plavljene. Spiraea salicifolia nije u sociološkom smislu jasno definirana i srednjoeuropski autori je svrstavaju kao svojstvenu vrstu za svezu Pruno-Rubion fruticosi Doing 62. Dva od tri opisana nalazišta suručice zaštićena su kao specijalni rezervati šumske vegetacije, dok je predjel Česme upravo predložen da bude zaštićen.